Development of selective catalysts for hydroprocessing of phenol production by-products — hydroquinone and catechol

Development of selective catalysts for hydroprocessing of phenol production by-products — hydroquinone and catechol | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Development of selective catalysts for hydroprocessing of phenol production by-products — hydroquinone and catechol Mariyam Mukhtarova, Maria A. Golubeva, Kirill I. Chernyshev, Alexander L. Vasiliev, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7609053/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract The development of a selective catalyst for hydroprocessing of phenol production by-products (hydroquinone and catechol) is an important task for increasing the yield of the target product. In this study, the use of in situ generated catalysts based on molybdenum and tungsten compounds (MoP, WP, MoO x , and WO x ) was proposed for this goal. The performance of the catalysts was investigated in the hydroprocessing of each individual substrate (hydroquinone and catechol), as well as their mixture. It was shown that MoP and WP catalysts were more selective in the partial HDO of hydroquinone and catechol into phenol compared to their oxides, as a result, the selectivity for phenol was higher. The hydroprocessing of a mixture of phenol, hydroquinone, and catechol (the molar ratio of phenol/hydroquinone/catechol = 7/2/1) was also explored using in situ formed MoP, WP, MoO x , and WO x catalysts. The phenol content in the product mixture after the reaction changed in the following order: WP (88%) > MoP (75%) > WO x (55%) > > MoO x (26%). Thus, in situ formed MoP and WP can be considered as the suitable catalysts for the selective HDO of hydroquinone and catechol towards phenol. phenol catechol hydroquinone transition metal oxide transition metal phosphide Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Phenol is one of the most important industrial chemicals, which is widely used for the synthesis of phenol resins, bisphenol A, epoxy resins, etc. The conventional methods for phenol production, primarily the cumene process, have several limitations, such as high energy consumption, low yield of phenol, equimolar amounts of a by-product (acetone), potential environmental concerns [1 − 4]. Currently, the development of green and efficient approaches for chemical synthesis, including for the production of phenol, is one of the crucial tasks of the scientific community. Direct transformation of arenes to phenol via hydroxylation reaction using various oxidants (H 2 O 2 , O 2 , N 2 O) is a one-step alternative method for environmentally friendly synthesis of phenol [1, 3 − 5]. However, the formation of by-products (hydroquinone and catechol) during the oxidation of phenol is the major disadvantage of this process [3, 6 − 9]. Additionally, hydroquinone, catechol and other phenol derivatives can also be formed by lignin depolymerization [10 − 13]. The selective hydroprocessing of hydroquinone and catechol towards phenol, in turn, can significantly increase the yield of the target product. However, most of the catalysts proposed in the literature promote the direct hydrogenation of dihydroxybenzenes (hydroquinone and catechol) to dihydroxycyclohexanes, and the selectivity for phenol was low [11, 14 − 16]. For instance, Li et al. studied the performance of the series of Ru-based catalysts modified by alkaline earth metals in the hydrogenation of hydroquinone [ 14 ]. The major reaction product was 1,4-dihydroxycyclohexane, the selectivity for which reached up to 99.6% (150°C, 5 MPa, 3 h). Moreover, the use of Ni-based catalysts promoted the hydrogenation reaction as dominant in the hydroprocessing of hydroquinone. The highest selectivity for 1,4-dihydroxycyclohexane was 96.7% over a Ni–Sr/γ-Al 2 O 3 catalyst at 99.2% conversion [ 15 ]. Song et al. explored the activity of Ni-containing unsupported and supported on HZSM-5 catalysts in the conversion of phenol, catechol, and guaiacol in the aqueous phase [ 16 ]. For catechol, it was shown that initially the deoxygenation of the aryl C-O bond and hydrogenation of the aromatic ring occurred in parallel. However, then the hydrogenation reaction dominated, and, as a result, 1,2-dihydroxycyclohexane was formed with around 85% yield after 120 min over Ni/HZSM-5 (200°C, 30 bar of H 2 ). In our previous studies, transition metal compound (oxide, phosphide) based catalysts were extensively studied in the hydroprocessing of various oxygen-containing substrates [17 − 19]. The objective of this work is to explore the possibility of the selective transformation of hydroquinone and catechol to phenol using in situ formed transition metal phosphides and oxides (MoP, WP, MoO x , and WO x ) in the autoclave reactor. These catalysts are characterized by high catalytic activity in hydrodeoxygenation (HDO) reactions, as well as lower cost compared to traditional hydroprocessing catalysts (noble metal containing catalysts). The proposed in situ method for the synthesis of transition metal phosphides and oxides is not accompanied by the release of harmful substances into the atmosphere. Moreover, such approach can significantly simplify the process due to the absence of a separate stage of catalyst synthesis. Furthermore, in situ formed transition metal oxides and phosphides have been shown to be reused without significant loss of activity. 2. Experimental section 2.1. Materials The chemicals used for in situ catalyst synthesis are molybdenum hexacarbonyl (LLC «Redkino experimental plant», Redkino, Russia, 36.5–37.5 wt% of Mo), tungsten hexacarbonyl (LLC «Redkino experimental plant», Redkino, Russia, 51–52% wt% of W), trioctylphosphine (Sigma-Aldrich, USA, 97%). Phenol (Reachem, Russia, pure), catechol (Alfa Aesar, United Kingdom, 99%), and hydroquinone (Reachem, Russia, pure) were employed as substrates, dodecane (Component-reaktiv, Russia, > 99%) was used as a solvent. Ethyl acetate (Component-reaktiv, Russia, 99.7%) was used to remove unreacted substrates. Acetone (Component-reaktiv, Russia, > 99.5%) and petroleum ether 40/70 (Component-reaktiv, Russia, tech.) were used for catalyst washing. 2.2. Catalytic tests It should be noted that all catalysts were formed in situ in the reaction medium without an additional stage. Generally, a mixture of 0.1 g of substrate, 1.5 g of solvent, and precursors was placed into the autoclave reactor. Mo(CO) 6 and W(CO) 6 were used as precursors for in situ synthesis of MoO x and WO x catalysts. In the case of MoP and WP, a mixture of metal carbonyls and tryoctylphosphine was used (the molar ratio of M/P = 1). The molar ratio of substrate/metal was 5. All the experiments were conducted at a constant stirring speed of 900 rpm. The experiments were carried out at 300 and 350°C, 5 MPa H 2 , for 4 h. After cooling the reactor to the ambient temperature, ethyl acetate was added to dissolve unreacted substrates, and the liquid reaction products were separated by centrifugation. The catalyst samples were washed with various solvents (acetone and petroleum ether 40/70) and dried in an Ar atmosphere. 2.3. Products analysis The liquid products were identified using a gas chromatography–mass spectrometer (Thermo Scientific ISQ 7000 GC-MS) equipped with a capillary column (Restek 5XI-17SIL MS CAP, 30 m × 0.25 mm × 0.25 µm). A gas chromatograph (Crystallux 4000 M) equipped with a flame ionization detector and capillary column (Optima-1, 25 m × 0.32 mm × 0.35 µm) was used for quantitative analysis of the reaction products. The conversion of substrates and product selectivity were calculated using the following equations: $$\:\text{C}\text{o}\text{n}\text{v}\text{e}\text{r}\text{s}\text{i}\text{o}\text{n}\:\left(\text{%}\right)=\:\frac{\text{m}\text{o}\text{l}\text{e}\:\text{o}\text{f}\:\text{s}\text{u}\text{b}\text{s}\text{t}\text{r}\text{a}\text{t}\text{e}\:\text{c}\text{o}\text{n}\text{s}\text{u}\text{m}\text{e}\text{d}}{\text{i}\text{n}\text{i}\text{t}\text{i}\text{a}\text{l}\:\text{m}\text{o}\text{l}\text{e}\:\text{o}\text{f}\:\text{s}\text{u}\text{b}\text{s}\text{t}\text{r}\text{a}\text{t}\text{e}}\times\:100\%$$ $$\:\mathbf{S}\mathbf{e}\mathbf{l}\mathbf{e}\mathbf{c}\mathbf{t}\mathbf{i}\mathbf{v}\mathbf{i}\mathbf{t}\mathbf{y}\:\left(\mathbf{\%}\right)=\:\frac{\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{e}\:\mathbf{o}\mathbf{f}\:\mathbf{p}\mathbf{r}\mathbf{o}\mathbf{d}\mathbf{u}\mathbf{c}\mathbf{t}}{\sum\:\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{e}\mathbf{s}\:\mathbf{o}\mathbf{f}\:\mathbf{a}\mathbf{l}\mathbf{l}\:\mathbf{p}\mathbf{r}\mathbf{o}\mathbf{d}\mathbf{u}\mathbf{c}\mathbf{t}\mathbf{s}}\times\:100\varvec{\%}$$ 2.4. Catalyst characterization The powder X-ray diffraction (XRD) was performed with a Rigaku Miniflex-600 diffractometer (Rigaku Corporation, Tokyo, Japan). XRD data were recorded using Cu-Kα radiation (40 kV, 15 mA, Ni-Kβ filter) in the 2θ range 10–80° at a scan rate of 0.5°/min. The PDF-2 ICDD database was used for phase identification with the help of integrated X-ray powder diffraction software (PDXL: Rigaku Diffraction Software). X-ray photoelectron spectroscopy (XPS) profiles were collected by a PREVAC EA15 electron spectrometer with AlK ɑ radiation (hν = 1486.74 eV, 150 W) and deconvoluted using the CasaXPS program. The specimens for the transmission and scanning transmission electron microscopy (TEM and STEM, correspondingly) were prepared by deposition of catalytic particles on copper grid coated with ultra-thin carbon film TEM/STEM were performed in a Osiris TEM/STEM (Thermo Fisher Scientific, USA) equipped with an energy dispersive X-ray (EDX) Super X spectrometer (ChemiSTEM, Bruker, USA) and high angle annular dark field (HAADF) detector (Fischione, USA) operating at an acceleration voltage of 200 kV. 3. Results and discussion 3.1. Catalyst characterization The catalysts (MoP, WP, MoO x , and WO x ) formed in situ during the hydroprocessing of a mixture of phenol, hydroquinone, and catechol (300°C, 5 MPa H 2 , 4 h) were studied using various physico-chemical methods. Metal carbonyls (Mo(CO) 6 and W(CO) 6 ) were used as precursors for the in situ synthesis of MoO x and WO x catalysts. In situ MoP and WP were prepared using metal carbonyls and trioctylphosphine. The possible pathways for the formation of transition metal (Mo, W) oxides and phosphides were discussed in detail in our previous study [ 19 ]. Figure S1 shows the XRD patterns of the MoP, WP, MoO x , and WO x . In situ MoP and MoO x are amorphous; that was also observed in the previous work. In situ WO x is crystalline and contains the W 18 O 49 phase (PDF #71 − 2450). The diffraction peaks at the 2θ of 23.5° and 48.1° are attributed to the (010) and (020) lattice planes in W 18 O 49 . The broad diffraction reflection related to the W 18 O 49 phase was also observed in the diffractogram of the in situ WP catalyst. One of the possible routes of molybdenum and tungsten phosphide formation can proceed through the formation of oxides and their subsequent phosphidation to metal phosphides [ 20 ]. According to the above discussion, in situ formed WP catalyst is a mixture of amorphous WP and some amounts of W 18 O 49 . The XPS method was applied to investigate the surface composition of the catalysts studied. The full XPS data, including the values of binding energy for all catalysts, is presented in Table S1 (MoP, WP) and Table S2 (MoO x , WO x ). The deconvoluted spectra of MoP and WP in Mo 3d and W 4f regions, respectively, include three doublets related to the following oxidation states: M δ+, M 4+ , and M 6+ (M = Mo or W). The M δ+ (M = Mo or W) peaks are attributed to molybdenum and tungsten phosphides, while the peaks of M 4+ and M 6+ can be assigned to their oxides and phosphates [ 21 , 22 ]. The P 2p spectra of MoP and WP catalysts are presented by two doublets related to P δ− in the corresponding phosphides and P 5+ in phosphates. The estimated surface content of M δ+ was 5% for MoP and 8% for WP, while the content of P δ− was 10% for MoP and 13% for WP. The presence of P 5+ is due to the surface oxidation of the samples. The metal sites (M δ+) , as well as Brønsted (P-OH) and Lewis (M n+ ) acid sites, are the crucial characteristics in the catalytic performance of transition metal phosphides. The doublets of M n+ (n = 4, 5, 6) in the Mo 3d and W 4f regions in the spectra of MoO x and WO x are associated with their oxides. The presence of Mo 5+ and W 5+ directly indicates the formation of oxygen vacancies (OVs), which are produced via the partial reduction of metal oxides in a hydrogen atmosphere [ 23 , 24 ]. Moreover, for MoO x , the content of Mo 5+ (16%) is higher compared to the content of W 5+ (10%) in WO x . The O 1s spectra for molybdenum and tungsten oxides were deconvoluted into three peaks corresponding to their oxides (M-O), OVs, and M-OH groups. M-OH are formed by the adsorption of water generated during HDO reactions. According to the XPS results in the O 1s region, the content of OVs for MoO x (17%) is also higher than for WO x (11%). The content of OVs in transition metal oxides primarily influences the catalytic performance in HDO reactions. The morphology and crystal structure of in situ obtained MoP, WP, MoO x , and WO x catalysts was characterized by TEM including high resolution (HR) TEM (Fig. 2 ). Similar to the XRD results, in situ MoP and WP samples are amorphous, but a number of particles and their agglomerates reveal crystalline structure and that was observed on HRTEM images. As shown in Fig. 2 a, the observed lattice spacing of 0.204 nm corresponds to the (101) interplane distance of MoP (PDF #24–771), and the lattice spacing of 0.292 nm belongs to the (011) of WP (PDF #29-1364). The difference between XRD and HRTEM results may be attributed to the small dimension of crystalline particles. As displayed in Fig. S2, the metal (Mo or W), P, and O were uniformly distributed in the particles of MoP and WP samples. The presence of oxygen atoms may be attributed to the partial oxidation of phosphides to phosphates or to the existence of metal oxides that were not fully converted to phosphides during the phosphidation process. In situ MoO x catalyst represents agglomerates of particles (Fig. 2 b). According to the HRTEM image of in situ MoO x , the two lattice spacings of 0.218 and 0.286 nm are attributed to the (101) of MoO 2 (PDF #50–739) and to the (212) of Mo 4 O 11 (PDF #73-1538). In situ WO x contains agglomerates of particles surrounded by nanorods. The lattice spacing of 0.378 nm was found in the nanorods, which match to the (010) of W 18 O 49 (PDF #71-2450). Additionally, the lattice spacing of 0.236 nm was observed, which fits to the (002) crystal plane of WO 2 (PDF #71–614). As shown in the [ 17 , 25 ], the in situ transformations of metal carbonyls (Mo(CO) 6 and W(CO) 6 ) during HDO reactions undergo through following stages: Mo(CO) 6 → MoO 3 → Mo 4 O 11 → MoO 2 and W(CO) 6 → WO 3 → W 18 O 49 → WO 2 , respectively. In the present study, the reaction conditions were moderate (300°C, 5 MPa H 2 , 4 h), and the complete reduction into MoO 2 and WO 2 was not achieved. The uniform distribution of metal and oxygen atoms can be observed in the elemental maps of in situ MoO x and WO x samples (Fig. S3). 3.2. Catalytic tests Hydroprocessing of hydroquinone and catechol Hydroprocessing of hydroquinone and catechol was studied at 300 and 350°C (5 MPa, 4 h) using in situ formed metal (Mo or W) oxides and phosphides. Figure 3 shows the proposed scheme of catechol and hydroquinone transformations using catalysts studied. Initially, phenol is formed via direct deoxygenation (DDO) of both dihydroxybenzenes. The further conversion of phenol can proceed by its hydrogenation (HYD) into cyclohexanol or DDO to benzene [ 26 , 27 ]. Cyclohexene and cyclohexanol were not detected among the reaction products; however, these compounds can be intermediates in the stepwise pathway leading to the formation of cyclohexane [16, 28 − 30]. Hydrogenation of cyclohexene produced cyclohexane and methylcyclopentane, which can be converted into each other via isomerization [ 27 , 31 ]. The full conversion of both substrates was achieved in the presence of in situ MoO x and WO x . In the case of in situ MoP and WP, the conversion of hydroquinone and catechol was 92 − 98% (Fig. 4 ). The hydroprocessing of hydroquinone using MoO x at 300°C produces a mixture of benzene, cyclohexane, and phenol. As the temperature increased from 300 to 350°C the selectivity for phenol decreased from 30 to 1%, and the selectivity for benzene increased from 23 to 40%, which is associated with the occurrence of phenol DDO to benzene (Fig. 4 ). The selectivity for methylcyclopentane rose from 1 to 22%, and the selectivity for cyclohexane decreased from 46 to 36% with an increase in the reaction temperature from 300 to 350°C. This result can be due to isomerization of cyclohexane to methylcyclopentane. For MoP, an increase in reaction temperature from 300 to 350°C resulted in a decrease in phenol selectivity from 83% to 62%. Increasing the reaction temperature promoted DDO of phenol to benzene and further formation of cyclohexane. In the case of hydroquinone hydroprocessing using WO x , with an increase in temperature from 300 to 350°C, the selectivity for phenol significantly decreased from 75 to 31%, which is due to its conversion to benzene (selectivity 42%) and to methylcyclopentane (selectivity 23%). For WP, the selectivity for phenol maintained high selectivity for phenol even with an increase in temperature and was 80% at 300°C and 95% at 350°C (Fig. 4 ). Furthermore, hydroprocessing of catechol was studied at 300 and 350°C. Phenol was the major reaction product of catechol conversion over WO x (59%), WP (90%), and MoP (64%) catalysts at 300°C. For WP and MoP, the selectivity for phenol decreased to 76% and 43% at 350°C, respectively. However, in the case of WO x , as the reaction temperature increased to 350°C, the selectivity for products such as benzene, cyclohexane, and methylcyclopentane significantly increased, and the selectivity for phenol decreased to 25%. The use of MoO x as a catalyst in the hydroprocessing of catechol resulted in the formation of cyclohexane (68%) and benzene (30%). When the reaction temperature increased from 300 to 350°C, the selectivity for cyclohexane decreased to 45% due to its conversion to methylcyclopentane. As shown for another oxygen-containing substrate, guaiacol, the high selectivity in the partial HDO of guaiacol to phenol was retained at the temperatures below 300°C using in situ MoO x and WO x [ 17 ]. Generally, the elimination of the OH-group in the ortho-position with phenol formation occurred faster than in the para-position [ 28 , 32 ]. Some authors also noted the higher adsorbability of catechol compared to hydroquinone [ 33 , 34 ]. Figure 5 shows the schematic illustration of hydroquinone and catechol HDO over different active sites of in situ formed metal (Mo or W) phosphides and oxides. In the case of MoO x and WO x , DDO reactions occur over OVs and acid sites (M n+ and M n+ -OH). Moreover, OVs are also considered as active sites involved in HYD [ 35 ]. In the case of MoP and WP, metal sites (M δ+ ) are active in HYD reactions and Brønsted/Lewis acid sites (M n+ , M n+ -OH and P-OH) in DDO [ 19 ]. Thus, MoP and WP are more selective in the partial deoxygenation of catechol and hydroquinone to phenol. The use of MoO x in the conversion of catechol and hydroquinone promoted the formation of methylcyclopentane, benzene, and cyclohexane. Their selectivity changed depending on the reaction temperature. WO x maintains the phenol selectivity of 59 − 75% at low temperature, but at 350°C selectivity for benzene, cyclohexane, and methylcyclopentane significantly increased. Hydroprocessing of the hydroquinone and catechol mixture In situ MoO x , WO x , MoP, and WP were also tested in the hydroprocessing of a hydroquinone and catechol mixture at their different molar ratio (Cat/Hydr = 1 and 2). The results are presented in Table 1 . An increase of the Cat/Hydr molar ratio from 1 to 2 had an insignificant effect on conversion in the case of MoO x , WO x , and MoP catalysts. For WP, the conversion of substrates was 89% at the molar ratio of Cat/Hydr = 2 and 70% at the Cat/Hydr = 1. As was shown in the previous studies, the conversion of other oxygen-containing compounds (terephthalic acid, benzoic acid, p-methylbenzoic acid, guaiacol) using in situ WP was lower compared to MoO x , WO x , MoP [17 − 19]. An increase in the molar ratio of catechol/hydroquinone also affected the selectivity for phenol. In the case of MoO x and MoP, the selectivity for phenol was 60% (MoO x ) and 80% (MoP) at a Cat/Hydr = 1, and decreased to 54% (MoO x ) and 65% (MoP) at a Cat/Hydr = 2. As shown for hydroprocessing of the individual compounds, DDO of catechol to phenol and the subsequent transformations to other products (benzene, cyclohexane, and methylcyclopentane) occurred faster than for hydroquinone. As a result, the selectivity for phenol was lower as the molar ratio of Cat/Hydr increased. The similar results were observed for tungsten-containing catalysts (Table 1 ). For example, the selectivity for phenol was 91% at a Cat/Hydr = 1 and 85% at a Cat/Hydr = 2 using WP as a catalyst. Table 1 Influence of the catechol/hydroquinone molar ratio on the conversion of substrates and selectivity for phenol. Cat/Hydr = 1 Catalyst MoO x WO x MoP WP Selectivity for phenol, % 60 72 80 91 Conversion, % 87 88 86 70 Cat/Hydr = 2 Catalyst MoO x WO x MoP WP Selectivity for phenol, % 54 58 65 85 Conversion, % 86 89 88 89 Hydroprocessing of the phenol, hydroquinone, and catechol mixture As was noted above, catechol and hydroquinone are by-products of the phenol production by oxidative method. Therefore, the selective conversion of the resulting by-products into phenol can increase the yield of the target product. Depending on the type of catalyst and the reaction conditions, the molar ratio of catechol/hydroquinone can vary in the range of 1 − 3 [36 − 39]. To study the possibility of increasing the yield of phenol, the activity of in situ formed transition metal phosphide and oxide based catalysts was explored in the hydroprocessing of a mixture of phenol, hydroquinone, and catechol (Fig. 6 ). The molar ratio of phenol/hydroquinone/catechol was 7/2/1. The phenol content in the product mixture after the reaction changed following WP (88%) > MoP (75%) > WO x (55%) > > MoO x (26%). MoO x is highly active in DDO reaction due to the fact that the main reaction was DDO of phenol to benzene (45%) and cyclohexane (16%). Because of less content of OVs in WO x compare to MoO x , the selectivity for full-deoxygenated products (benzene, cyclohexane, methylcyclopentane) was lower for WO x . In the case of MoP and WP, the hydroprocessing of catechol and hydroquinone towards phenol was predominant. Thus, it was shown that by-products (hydroquinone and catechol) formed during the production of phenol by the oxidative method can be selectively transformed into the target product – phenol, using in situ MoP and WP catalysts. 4. Conclusions For the first time, in situ formed MoP, WP, MoO x and WO x catalysts were tested in the hydroprocessing of hydroquinone, catechol, and their mixture. The formation of metal (Mo or W) phosphides and oxides was confirmed using various physico-chemical techniques (XRD, XPS, HRTEM). According to the HRTEM, in situ formed molybdenum and tungsten phosphides are presented by MoP and WP phases. While in situ obtained MoO x and WO x catalysts are the mixtures of their various oxides: MoO 2 and Mo 4 O 11 in MoO x , W 18 O 49 and WO 2 in WO x . The differences between active sites over MoP, WP, MoO x , and WO x catalysts were shown by the XPS method. Regarding the results of the catalytic tests, MoP and WP are more selective catalysts in the partial HDO of catechol and hydroquinone into phenol than MoO x and WO x . The highest selectivity for phenol was 83% and 95% over MoP and WP, respectively. Due to the high content of OVs, MoO x contributed to the full HDO of catechol and hydroquinone with the production of methylcyclopentane, benzene, and cyclohexane. Phenol was formed with 59 − 75% selectivity using WO x catalysts in HDO of both substrates. However, as temperature increased, the selectivity for phenol significantly decreased due to its transformation to benzene, cyclohexane, and methylcyclopentane. Moreover, the HDO of catechol occurred faster compared to hydroquinone. In addition, the hydroprocessing of a mixture of phenol, hydroquinone, and pyrocatechol (by-products of phenol production), was investigated in order to study the possibility of increasing the yield of the target product. The phenol content in the product mixture after the reaction changed as follows: WP (88%) > MoP (75%) > WO x (55%) > > MoO x (26%). Thus, in situ formed MoP and WP can be considered as the suitable catalysts for the selective HDO of hydroquinone and pyrocatechol towards phenol. Abbreviations HDO hydrodeoxygenation; XRD powder X-ray diffraction; XPS X-ray photoelectron spectroscopy; HRTEM high-resolution transmission electron spectroscopy; STEM scanning transmission electron microscopy; EDX energy-dispersive X-ray spectroscopy; HAADF high angle annular dark field; OVs oxygen vacancies; DDO direct deoxygenation; HYD hydrogenation. Declarations Ethics and Consent to Participate The authors are dedicated to maintaining the integrity of the scientific record and fully adhering to the Committee on Publication Ethics (COPE) guidelines during the preparation and submission of this paper. Consent for Publication All authors have read and approved the final manuscript and consent to its publication in this journal. Competing Interest The authors declare no competing interests. Funding This research was funded by a grant from the Ministry of Science and Higher Education of the Russian Federation, grant number 075-15-2024-646. Author Contribution Mariyam Mukhtarova: Writing – original draft, Writing – review & editing, Validation, Formal analysis, Visualization, Investigation, Conceptualization. Maria A. Golubeva: Writing – review & editing, Validation, Project administration, Supervision. Kirill I. Chernyshev: Formal analysis, Investigation. Alexander L. Vasiliev: Resources. Dzhamalutdin N. Ramazanov: Formal analysis. Oleg G. Sinyashin: Project administration, Funding acquisition. Anton L. Maximov: Conceptualization, Project administration, Supervision, Funding acquisition. Acknowledgement The authors thank Dr. Andrey L. Golovin from A.V. Shubnikov Institute of Crystallography RAS for the XRD analysis and Alexey A. Sadovnikov from TIPS RAS for the XPS analysis.This work was performed using the equipment of the Shared Research Center Analytical Center of Deep Oil Processing and Petrochemistry of A.V. Topchiev Institute of Petrochemical Synthesis RAS.Electron microscopic study was carried out within the framework of the state assignment of the National Research Center "Kurchatov Institute". Data Availability No data was used for the research described in the article. References Wang H, Wang C, Zhao M, Yang Y, Fang L, Wang Y (2018) H 5 PMo 10 V 2 O 40 anchor by OH of the Titania nanotubes: Highly efficient heterogeneous catalyst for the direct hydroxylation of benzene. Chem Eng Sci 177:399–409. https://doi.org/10.1016/j.ces.2017.11.023 Dai X, Zhou W, Yang S, Sun F A, Qian J, He M, Chen Q (2019) Microchannel process for phenol production via the cleavage of cumene hydroperoxide. Chem Eng Sci 199:398–404. https://doi.org/10.1016/j.ces.2019.01.031 Naranov E, Ramazanov D, Agliullin M, Sinyashin O, Maximov A (2024) Recent Advances in Aromatic Hydroxylation to Phenol and Hydroquinone Using H 2 O 2 . Catalysts 14 (12):930. https://doi.org/10.3390/catal14120930 Wang W, Tang H, Jiang X, Huang F E, Ma Y (2019) Quinone–amine polymers as metal–free and reductant–free catalysts for hydroxylation of benzene to phenol with molecular oxygen. Chem Commun 55 (54):7772–7775. https://doi.org/10.1039/C9CC03623G Wen G, Wu S, Li B, Dai C, Su DS (2015) Active sites and mechanisms for direct oxidation of benzene to phenol over carbon catalysts. Ang Chem Int Ed 54(13):4105–4109. https://doi.org/10.1002/anie.201410093 Yang JH, Sun G, Gao Y, Zhao H, Tang P, Tan J, Ma D (2013) Direct catalytic oxidation of benzene to phenol over metal–free graphene–based catalyst. Energy Environ Sci 6(3):793–798. https://doi:10.1039/c3ee23623d Molinari R, Poerio T (2010) Remarks on studies for direct production of phenol in conventional and membrane reactors. Asia–Pac J Chem 5 (1):191–206. https://doi.org/10.1002/apj.369 Centi G, Perathoner S (2009) One–step H 2 O 2 and phenol syntheses: examples of challenges for new sustainable selective oxidation processes. Catal Today 143(1–2):145–150. https://doi.org/10.1016/j.cattod.2008.09.032 Makatsa TJ, Baloyi J, Ntho T, Masuku CM (2021) Catalytic wet air oxidation of phenol: Review of the reaction mechanism, kinetics, and CFD modeling. Crit Rev Environ Sci Technol 51(17):1891–1923. https://doi.org/10.1080/10643389.2020.1771886 Wang Q, Shamzhy M, Heuson E, Trentesaux M., Marinova M, Addad A, Ordomsky VV (2024) Isomerization of dihydroxybenzenes over metal–zeolite catalysts through the carbonaceous deposits. Chem Eng J 491:151956. https://doi.org/10.1016/j.cej.2024.151956 Wang Y, Han C, Fu Z, Xiang M, Liu T, Zhang X, Wang Y (2025) Ultra–small Ru nanoparticles supported on MgO modified Al 2 O 3 for efficient selective hydrogenation of hydroquinone to 1,4-cyclohexanediol. Appl Catal O: Open 206:207058. https://doi.org/10.1016/j.apcato.2025.207058 Pan Z, Puente-Urbina A, Bodi A, van Bokhoven JA, Hemberger P (2021) Isomer–dependent catalytic pyrolysis mechanism of the lignin model compounds catechol, resorcinol and hydroquinone. Chem Sci 12(9):3161–3169. https://doi.org/10.1039/D1SC00654A Zhao C, He J, Lemonidou AA, Li X, Lercher JA (2011) Aqueous–phase hydrodeoxygenation of bio–derived phenols to cycloalkanes. J Catal 280(1):8–16. http://dx.doi.org/10.1016/j.jcat.2011.02.001 Li H, Ji D, Li Y, Liang Y, Li GX (2015) Effect of alkaline earth metals on the liquid–phase hydrogenation of hydroquinone over Ru–based catalysts. Solid State Sci 50: 85–90. https://doi.org/10.1016/j.solidstatesciences.2015.10.014 Bai G, Li F, Fan X, Wang Y, Qiu M, Ma Z, Niu L (2012) Continuous hydrogenation of hydroquinone to 1,4-cyclohexanediol over alkaline earth metal modified nickel–based catalysts. Catal Commun 17:126–130. https://doi.org/10.1016/j.catcom.2011.10.026 Song W, Liu Y, Baráth E, Zhao C, Lercher JA (2015) Synergistic effects of Ni and acid sites for hydrogenation and C–O bond cleavage of substituted phenols. Green Chem 17(2):1204–1218. https://doi.org/10.1039/c4gc01798f Mukhtarova M, Golubeva M, Sadovnikov A, Maximov A (2023) Guaiacol to aromatics: Efficient transformation over in situ -generated molybdenum and tungsten oxides. Catalysts 13(2):263. https://doi.org/10.3390/catal13020263 Golubeva MA, Mukhtarova M, Bugaev AL, Naranov ER (2022) In Situ Generated Dispersed Catalysts Based on Molybdenum and Tungsten Phosphides in Hydroprocessing of Guaiacol. Pet Chem 62(11):1300–1307. https://doi.org/10.1134/S0965544122110019 Mukhtarova M, Golubeva MA, Maximov A L (2025) Comparison of In Situ Formed Metal (Mo, W) Phosphides and Oxides in the Hydroprocessing of Used PET Bottles. ACS Sustainable Chem Eng 13(17):6307–6317. https://doi.org/10.1021/acssuschemeng.5c00986 Chen F, Zhao B, Sun M, Liu C, Shi Y, Yu Y, Zhang B (2022) Mechanistic insight into the controlled synthesis of metal phosphide catalysts from annealing of metal oxides with sodium hypophosphite. Nano Res 15(12):10134–10141. https://doi.org/10.1007/s12274–022–4489–x Long B, Ma J, Song T, Song S, Tong Y, Wang X (2021) Intercalation–type MoP and WP nanodots with abundant phase interface embedded in carbon microflower for enhanced Li storage and reaction kinetics. Electrochim Acta 365:137354. https://doi.org/10.1016/j.electacta.2020.137354 Peng S, Fu Q, Chen E, Li Y (2024) Coupling amorphous WO 3 with WP as a cocatalyst for efficient dye–sensitizated photocatalytic hydrogen evolution. Int J of Hydrogen Energy 64:791–797. https://doi.org/10.1016/j.ijhydene.2024.03.276 Ciftyurek E, Li Z, Schierbaum K (2022) Adsorbed oxygen ions and oxygenies: their concentration and distribution in metal oxide chemical sensors and influencing role in sensitivity and sensing mechanisms. Sensors 23(1):29. https://doi.org/10.3390/s23010029 Cao S, Zeng Y, Li Y, Da K, Chen W, Yang J, Fan X (2025) The presence of Mo and O double vacancies in Bi 2 W 0.25 Mo 0.75 O 6 solid solution promotes photogenerated charge separation and molecular oxygen activation for efficient removal of gaseous toluene under visible light. Sep Purif Technol 354:128958. https://doi.org/10.1016/j.seppur.2024.128958 Mukhtarova M, Golubeva MA, Sadovnikov AA, Maximov AL (2024) Selective hydroprocessing of diphenyl ether into benzene over in situ generated MoO x and WO x . Appl Catal B 351:123999. https://doi.org/10.1016/j.apcatb.2024.123999 Mu W, Ben H, Ragauskas A, Deng Y (2013) Lignin pyrolysis components and upgrading—technology review. Bioenergy Res 6(4):1183–1204. http://dx.doi.org/10.1007/s12155–013–9314–7 Ranga C, Lødeng R, Alexiadis VI, Rajkhowa T, Bjørkan H, Chytil S, Thybaut JW (2018) Effect of composition and preparation of supported MoO 3 catalysts for anisole hydrodeoxygenation. Chem Eng J 335:120–132. https://doi.org/10.1016/j.cej.2017.10.090 Kirkwood K, Jackson SD (2021) Competitive hydrogenation and hydrodeoxygenation of oxygen-substituted aromatics over Rh/silica: catechol, resorcinol and hydroquinone. Top Catal 64(17):934–944. https://doi.org/10.1007/s11244–021–01422–3 Xia H, Tan H, Cui H, Song F, Zhang Y, Zhao R, Li Z (2021) Tunable selectivity of phenol hydrogenation to cyclohexane or cyclohexanol by a solvent–driven effect over a bifunctional Pd/NaY catalyst. Catal Sci Technol 11(5):1881–1887. https://doi.org/10.1039/d0cy02188a Mao J, Zhao B, Zhou J, Zhang L, Yang F, Guo X, Zhang ZC (2019) Identification and characteristics of catalytic quad–functions on Au/Anatase TiO 2 . ACS Catal 9(9):7900–7911. http://dx.doi.org/10.1021/acscatal.9b02090 Xu H, Li Z, Meng S, Jarvis J, Song H (2021) Highly selective skeletal isomerization of cyclohexene over zeolite-based catalysts for high–purity methylcyclopentene production. Commun Chem 4(1):34. https://doi.org/10.1038/s42004–021–00472–8 Kirkwood K, Jackson SD (2020) Hydrogenation and hydrodeoxygenation of oxygen–substituted aromatics over Rh/silica: Catechol, resorcinol and hydroquinone. Catalysts 10(5):584. https://doi.org/10.3390/catal10050584 Suresh S, Srivastava VC, Mishra IM (2012) Adsorption of catechol, resorcinol, hydroquinone, and their derivatives: a review. Int J Energy Environ Eng 3(1):32. https://doi.org/10.1186/2251–6832–3–32 Saiz‐Poseu J, Mancebo‐Aracil J, Nador F. Busqué F, Ruiz‐Molina D (2019) The chemistry behind catechol‐based adhesion. Angew Chem Int Ed 58(3):696–714. https://doi.org/10.1002/anie.201801063 Jin F, Yang X, Yang J, Lei Y, Xu W, Jiang W, Li X (2024) Unraveling the influence of oxygen vacancies in MoO x catalysts on CO 2 hydrogenation. Chem Eng J 495:153333. https://doi.org/10.1016/j.cej.2024.153333 Hocking MB, Intihar DJ (1985) Oxidation of phenol by aqueous hydrogen peroxide catalysed by ferric ion‐catechol complexes. J Chem Technol Biotechnol 35(7):365–381. https://doi.org/10.1002/jctb.5040350706 Villa AL, Caro CA, de Correa CM (2005) Cu–and Fe–ZSM–5 as catalysts for phenol hydroxylation. J Mol Catal A Chem 228(1–2):233–240. https://doi.org/10.1016/j.molcata.2004.09.035 Wu C, Kong Y, Gao F, Wu Y. Lu, Y, Wang J, Dong L (2008) Synthesis, characterization and catalytic performance for phenol hydroxylation of Fe–MCM41 with high iron content. Microporous and Mesoporous Mater 113(1–3):163–170. https://doi.org/10.1016/j.micromeso.2007.11.013 Atoguchi T, Kanougi T, Yamamoto T, Yao S (2004) Phenol oxidation into catechol and hydroquinone over H–MFI, H–MOR, H–USY and H–BEA in the presence of ketone. J Mol Catal A Chem 220(2):183–187. https://doi.org/10.1016/j.molcata.2003.10.026 Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.docx Graphicalabstract.jpg Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 13 Oct, 2025 Reviews received at journal 11 Oct, 2025 Reviews received at journal 05 Oct, 2025 Reviewers agreed at journal 01 Oct, 2025 Reviewers agreed at journal 29 Sep, 2025 Reviewers invited by journal 29 Sep, 2025 Editor assigned by journal 26 Sep, 2025 Submission checks completed at journal 26 Sep, 2025 First submitted to journal 13 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7609053","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":528162748,"identity":"3c8adafb-71ec-4c36-b08c-93102f690ed3","order_by":0,"name":"Mariyam Mukhtarova","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0klEQVRIiWNgGAWjYFACNjYog/nAAeK1QJSyJZCshceAOA26M9LSHn+ouSdncPzMx8MFfxjk+Rt4n0ng02J2I+24wYFjxcYGZ3I3HJ7ZxmA44wC7GQEt6W0SB9gSEmc2ALXwNjAwbgA6lQgt/4Ba+t88OMzzh8GeCC1pxyQOtiUk9kvkMBzmYWNIJKzlzLM0ibN9Ccb8Es8MgH6RSJ5xmI3ZAq+W42lmEhXfEuTY+JMffy74Y2Pb397GeAOfFhTAzMAgASaJByQpHgWjYBSMgpEDAFuVSDIM3un7AAAAAElFTkSuQmCC","orcid":"","institution":"Russian Academy of Sciences","correspondingAuthor":true,"prefix":"","firstName":"Mariyam","middleName":"","lastName":"Mukhtarova","suffix":""},{"id":528162750,"identity":"d250ef5e-0af4-4fca-8102-05ae22bc2610","order_by":1,"name":"Maria A. Golubeva","email":"","orcid":"","institution":"Russian Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Maria","middleName":"A.","lastName":"Golubeva","suffix":""},{"id":528162751,"identity":"e01ed18e-db58-4f3d-902c-b59154306103","order_by":2,"name":"Kirill I. Chernyshev","email":"","orcid":"","institution":"National Research Center “Kurchatov Institute”","correspondingAuthor":false,"prefix":"","firstName":"Kirill","middleName":"I.","lastName":"Chernyshev","suffix":""},{"id":528162752,"identity":"21344de1-98df-47f3-a1c5-d0af6b96e096","order_by":3,"name":"Alexander L. Vasiliev","email":"","orcid":"","institution":"National Research Center “Kurchatov Institute”","correspondingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"L.","lastName":"Vasiliev","suffix":""},{"id":528162753,"identity":"3d942889-883b-47d6-ba34-57758a8797ab","order_by":4,"name":"Dzhamalutdin N. Ramazanov","email":"","orcid":"","institution":"Russian Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Dzhamalutdin","middleName":"N.","lastName":"Ramazanov","suffix":""},{"id":528162754,"identity":"00cfd3ad-3c44-4bf9-a51a-e19de5266bbe","order_by":5,"name":"Oleg G. Sinyashin","email":"","orcid":"","institution":"Kazan Scientific Center RAS","correspondingAuthor":false,"prefix":"","firstName":"Oleg","middleName":"G.","lastName":"Sinyashin","suffix":""},{"id":528162755,"identity":"acead598-24b6-4a5d-8c4b-179ee0d8b99c","order_by":6,"name":"Anton L. Maximov","email":"","orcid":"","institution":"Russian Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Anton","middleName":"L.","lastName":"Maximov","suffix":""}],"badges":[],"createdAt":"2025-09-13 18:38:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7609053/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7609053/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":93459833,"identity":"ba305ecc-2e6f-4c8c-adf2-f368b5d1e190","added_by":"auto","created_at":"2025-10-14 06:02:07","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2791605,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/f2377385ef2592ab9de0b447.docx"},{"id":93459114,"identity":"e5851eeb-5e20-46fe-85ad-662aaf54397a","added_by":"auto","created_at":"2025-10-14 05:54:05","extension":"tif","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1852684,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/11b3a543cbac0076a06b0c39.tif"},{"id":93459179,"identity":"c8af4c61-2558-49b5-86e6-2e9a4cce541f","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"tif","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1615698,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/9f8e69f80ef50bce9af447ad.tif"},{"id":93459144,"identity":"5dbe51da-fa98-473d-8153-d973eaf22ecf","added_by":"auto","created_at":"2025-10-14 05:54:09","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":13026,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/c23174c6f76182864ed18144.docx"},{"id":93459130,"identity":"e03c2de7-d3ec-4218-81d8-145c01529970","added_by":"auto","created_at":"2025-10-14 05:54:07","extension":"tif","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7996404,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/87bf99f32953bcbce62ec7a3.tif"},{"id":93459113,"identity":"f0890801-7e1f-48be-930c-feac981c06f0","added_by":"auto","created_at":"2025-10-14 05:54:05","extension":"tif","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":542044,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/68582019a83e13e4f08434df.tif"},{"id":93459125,"identity":"4ebe3109-b90f-448b-974e-a953fa671cf9","added_by":"auto","created_at":"2025-10-14 05:54:06","extension":"tif","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":535658,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/48c2a292bc00be3fde79b0ac.tif"},{"id":93459137,"identity":"f16a4eea-7c62-4b2b-9907-fc68c155cea4","added_by":"auto","created_at":"2025-10-14 05:54:08","extension":"tif","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1151894,"visible":true,"origin":"","legend":"","description":"","filename":"Figure4.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/399007dcec64db2df2e54cbe.tif"},{"id":93459167,"identity":"b1c03687-0c97-4e0b-9157-188638a0e557","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"tif","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1374426,"visible":true,"origin":"","legend":"","description":"","filename":"Figure4b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/33f4dedcbccb6b4f9d3fc2da.tif"},{"id":93459159,"identity":"f4d3d27c-1791-4cad-84e5-93eedbf654c9","added_by":"auto","created_at":"2025-10-14 05:54:09","extension":"tif","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1095328,"visible":true,"origin":"","legend":"","description":"","filename":"Figure5.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/33c728f6de5e7c93631a44e8.tif"},{"id":93459851,"identity":"3e49ac52-4636-4a93-8704-8b4c331a2eee","added_by":"auto","created_at":"2025-10-14 06:02:10","extension":"tif","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1052150,"visible":true,"origin":"","legend":"","description":"","filename":"Figure5b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/f50daded2b3966a7d742a35c.tif"},{"id":93459856,"identity":"93c212ed-c488-440c-976f-11741d2dd815","added_by":"auto","created_at":"2025-10-14 06:02:11","extension":"tif","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":497454,"visible":true,"origin":"","legend":"","description":"","filename":"Figure6.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/40774d6d2b04a1a731292910.tif"},{"id":93459169,"identity":"8d264d9a-9de4-449b-a2fa-7ac726981364","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"tif","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":569208,"visible":true,"origin":"","legend":"","description":"","filename":"Figure6b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/1f87029572f727cebbd497b4.tif"},{"id":93459848,"identity":"ba90a250-c12f-4b5d-a1a4-81ff68c8aba9","added_by":"auto","created_at":"2025-10-14 06:02:10","extension":"docx","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":13071,"visible":true,"origin":"","legend":"","description":"","filename":"Figurecaptions.docx","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/f9c4fae66e1da07c7c97c8bc.docx"},{"id":93459177,"identity":"a00e535d-7a96-4e92-81a9-106b931c6b15","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"json","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":8610,"visible":true,"origin":"","legend":"","description":"","filename":"9d33cb2839f742bc9106f2177818f436.json","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/7db06f8b1eb2196a2dce36c5.json"},{"id":93459845,"identity":"33af55bc-90d4-4d64-b48a-9985c9a500cb","added_by":"auto","created_at":"2025-10-14 06:02:09","extension":"docx","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":3355180,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/eadbe9ee46a5e37fa625084f.docx"},{"id":93459115,"identity":"038f3837-d3d0-4715-a5b3-72fca48fa629","added_by":"auto","created_at":"2025-10-14 05:54:05","extension":"xml","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":128850,"visible":true,"origin":"","legend":"","description":"","filename":"9d33cb2839f742bc9106f2177818f4361enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/5a9975e2cd3d13ced2540c93.xml"},{"id":93459185,"identity":"e75a43fa-d706-4b2c-8c2d-a3b44c59eb14","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"tif","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1852684,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/f4ef219aa47d6efef65e9e66.tif"},{"id":93459157,"identity":"fda3bb17-36af-4dcd-a043-08f254927750","added_by":"auto","created_at":"2025-10-14 05:54:09","extension":"tif","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1615698,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/e961498b4d7b8fd1533c3466.tif"},{"id":93460534,"identity":"f67db104-c50a-40cc-9c82-9ce475bee380","added_by":"auto","created_at":"2025-10-14 06:10:10","extension":"tif","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7996404,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/a6b9eaa7c4260be8faae253b.tif"},{"id":93459847,"identity":"7b51d958-39c4-428c-98c5-3e0af8fafd30","added_by":"auto","created_at":"2025-10-14 06:02:10","extension":"tif","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":542044,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/10124ca375ed2ff975327eeb.tif"},{"id":93460533,"identity":"6c7fa13a-2c30-48c2-8d9b-e367fcb49b14","added_by":"auto","created_at":"2025-10-14 06:10:09","extension":"tif","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":535658,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/b5b15525752097fef3b84d2d.tif"},{"id":93459849,"identity":"818d967b-f189-449d-bca0-3a31adae7f05","added_by":"auto","created_at":"2025-10-14 06:02:10","extension":"tif","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1151894,"visible":true,"origin":"","legend":"","description":"","filename":"Figure4.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/192f7248f3a80252b84fa4fd.tif"},{"id":93459136,"identity":"5338a2f4-88cc-416b-93f3-b97da6e23e07","added_by":"auto","created_at":"2025-10-14 05:54:07","extension":"tif","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1374426,"visible":true,"origin":"","legend":"","description":"","filename":"Figure4b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/2119a44cf1d5493b52f71da8.tif"},{"id":93459128,"identity":"d493537d-c711-4912-81ea-b0b93054308c","added_by":"auto","created_at":"2025-10-14 05:54:07","extension":"tif","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1095328,"visible":true,"origin":"","legend":"","description":"","filename":"Figure5.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/27fcf062fa4633ba71b8e7a4.tif"},{"id":93459129,"identity":"af126e96-a10e-4c7c-b26b-a709752868c6","added_by":"auto","created_at":"2025-10-14 05:54:07","extension":"tif","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1052150,"visible":true,"origin":"","legend":"","description":"","filename":"Figure5b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/a5c9a8cd339b237ef013c10a.tif"},{"id":93459173,"identity":"d5eda5c5-7d67-4c14-b940-f1d61a232966","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"tif","order_by":27,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":497454,"visible":true,"origin":"","legend":"","description":"","filename":"Figure6.tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/a48d9dd792858447c91bb7bd.tif"},{"id":93459182,"identity":"ebb88ad2-7230-4879-99db-d80bd83eefb0","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"tif","order_by":28,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":569208,"visible":true,"origin":"","legend":"","description":"","filename":"Figure6b.w..tif","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/81569d70dacaf1cdc220c2ba.tif"},{"id":93459186,"identity":"7d977867-bf84-4eca-acf4-8539a1a6abc6","added_by":"auto","created_at":"2025-10-14 05:54:11","extension":"jpg","order_by":29,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":721437,"visible":true,"origin":"","legend":"","description":"","filename":"Graphicalabstract.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/18ae8a78f566bef2fea5c037.jpg"},{"id":93459846,"identity":"a366ddd8-75d1-491c-9d74-86ddd9a6b3ea","added_by":"auto","created_at":"2025-10-14 06:02:10","extension":"jpeg","order_by":30,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":500548,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/f5f68dbde3be92417d1df000.jpeg"},{"id":93459116,"identity":"124697de-16b6-4291-8ccb-84e5113f6f4e","added_by":"auto","created_at":"2025-10-14 05:54:05","extension":"jpeg","order_by":31,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1391408,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/bd7279d0c9de3fd98c5fd324.jpeg"},{"id":93459174,"identity":"65afff2d-6d8f-454d-ab1e-dec975387042","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"jpeg","order_by":32,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":117898,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/aa756053750378816bfbf1e4.jpeg"},{"id":93459147,"identity":"684aa9d5-ced9-4640-b7f5-34da3151d2fe","added_by":"auto","created_at":"2025-10-14 05:54:09","extension":"jpeg","order_by":33,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":315170,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/678ce31c3ac8c7c534c8e9ce.jpeg"},{"id":93459150,"identity":"8936300d-e2a1-47ca-b29c-5d3824afc372","added_by":"auto","created_at":"2025-10-14 05:54:09","extension":"jpeg","order_by":34,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":280540,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/04073447e14e8a1046e6cafb.jpeg"},{"id":93459123,"identity":"ed7c23cf-e889-400a-92d7-c4458de92725","added_by":"auto","created_at":"2025-10-14 05:54:06","extension":"jpeg","order_by":35,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":110010,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/41aa8ff454c6edf41b51fce8.jpeg"},{"id":93459171,"identity":"c92cf54d-be16-4cf6-8ab5-6b0c4907d857","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"png","order_by":36,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":300113,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/3f6a3d61cfdf1755d6ece191.png"},{"id":93459844,"identity":"a7c090ae-2b05-4c76-bade-4913ed408e74","added_by":"auto","created_at":"2025-10-14 06:02:09","extension":"png","order_by":37,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":273444,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure1b.w..png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/4f26474b9c723aa936932e17.png"},{"id":93459118,"identity":"aef5e518-4ab5-42b7-b063-f4a16529cf41","added_by":"auto","created_at":"2025-10-14 05:54:05","extension":"png","order_by":38,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":847016,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/a6937943869281cee72b1f6b.png"},{"id":93459133,"identity":"7d6316ba-1d56-4f09-8e42-7ff5cf279997","added_by":"auto","created_at":"2025-10-14 05:54:07","extension":"png","order_by":39,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":61795,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/fbc90f5c087435267edc819b.png"},{"id":93459176,"identity":"3f13cd52-65b2-4ca4-b9d5-3cb2f020ae10","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"png","order_by":40,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":61672,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure3b.w..png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/733be8690bb8b0b35053a669.png"},{"id":93459124,"identity":"a3dc8794-7462-4291-b252-f09c60aec451","added_by":"auto","created_at":"2025-10-14 05:54:06","extension":"png","order_by":41,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":140951,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/cf8e534390b1db298e5fad98.png"},{"id":93459829,"identity":"e1aef424-5dba-4963-9ce8-0fc0d49c4906","added_by":"auto","created_at":"2025-10-14 06:02:05","extension":"png","order_by":42,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":154683,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure4b.w..png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/75f1fb261517850219cc3e43.png"},{"id":93460532,"identity":"99f95b5a-2711-4d73-b677-c53506a34a20","added_by":"auto","created_at":"2025-10-14 06:10:05","extension":"png","order_by":43,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":156776,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/e63bd0d2b148707be539cb74.png"},{"id":93459187,"identity":"5856db74-1fbd-4cce-b94d-afd11e587365","added_by":"auto","created_at":"2025-10-14 05:54:11","extension":"png","order_by":44,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":146428,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure5b.w..png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/7a88e0c0954cc2b90e9111bb.png"},{"id":93459183,"identity":"86ec4548-6be4-4260-bdb6-5ce4160588e5","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"png","order_by":45,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":53510,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure6.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/a8bfd37414b7262384c26bb0.png"},{"id":93459122,"identity":"37a64647-153d-4567-9fe5-ebe00957a293","added_by":"auto","created_at":"2025-10-14 05:54:06","extension":"png","order_by":46,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":55632,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure6b.w..png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/e717dc9c18e65a2b1762b0b5.png"},{"id":93459841,"identity":"720bb01e-68a9-4175-9fe5-1a11224a4f57","added_by":"auto","created_at":"2025-10-14 06:02:09","extension":"png","order_by":47,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":253664,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineGraphicalabstract.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/9668c31d4aff63b03eeb28c2.png"},{"id":93459119,"identity":"ac282583-7505-4f8c-b30b-05c86ad3479c","added_by":"auto","created_at":"2025-10-14 05:54:05","extension":"png","order_by":48,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":84118,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/2d8cad9181c7ce06e23c4f2d.png"},{"id":93459834,"identity":"066adbe2-368f-4e44-af05-e186d18ad238","added_by":"auto","created_at":"2025-10-14 06:02:08","extension":"png","order_by":49,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":156799,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/7080067d7bc82535902a3519.png"},{"id":93459142,"identity":"42fab448-1987-4f3a-bf68-cd3640517a87","added_by":"auto","created_at":"2025-10-14 05:54:08","extension":"png","order_by":50,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":18083,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/000bbfb931022ca833ce3519.png"},{"id":93459139,"identity":"75666ce9-6eac-497c-b258-762a9bfddd39","added_by":"auto","created_at":"2025-10-14 05:54:08","extension":"png","order_by":51,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":36485,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/08c1f752506951920a5921ca.png"},{"id":93459132,"identity":"3c939a18-105d-48f4-8bf2-b3e2f8eff3c4","added_by":"auto","created_at":"2025-10-14 05:54:07","extension":"png","order_by":52,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":46150,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/b33306d97b46d8cd61fc2df6.png"},{"id":93460535,"identity":"ce740468-6834-4ff3-881f-48d88bcbb2ee","added_by":"auto","created_at":"2025-10-14 06:10:10","extension":"png","order_by":53,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":13701,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/7c71c8eb662f0e3a063f3c54.png"},{"id":93459149,"identity":"284fcd39-3be9-4de6-b664-c2f10a7d38b8","added_by":"auto","created_at":"2025-10-14 05:54:09","extension":"xml","order_by":54,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":128081,"visible":true,"origin":"","legend":"","description":"","filename":"9d33cb2839f742bc9106f2177818f4361structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/1a242b68b0e2aa5ef756ed9f.xml"},{"id":93459831,"identity":"ed1bc1bd-06b7-4280-8cb7-d25b642bb489","added_by":"auto","created_at":"2025-10-14 06:02:06","extension":"html","order_by":55,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":141797,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/b5666b900e1c7d0c914d8fb9.html"},{"id":93459152,"identity":"5ab5e2b6-8e09-466e-897e-bfb5188f3f4a","added_by":"auto","created_at":"2025-10-14 05:54:09","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2209581,"visible":true,"origin":"","legend":"\u003cp\u003eThe XPS profiles of the in situ obtained MoP (Mo 3d, P 2p), MoO\u003csub\u003ex\u003c/sub\u003e (Mo 3d, O 1s), WP (W 4f, P 2p), and WO\u003csub\u003ex\u003c/sub\u003e (W 4f, O 1s) catalysts. The catalysts were obtained \u003cem\u003ein situ\u003c/em\u003e during the hydroprocessing of a mixture of phenol, hydroquinone, and catechol at 300\u0026nbsp;°C, 5 MPa H\u003csub\u003e2\u003c/sub\u003e, 4 h.\u003c/p\u003e","description":"","filename":"Figure1.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/bb82ae8bce75653a66e68dfc.jpg"},{"id":93459843,"identity":"e35358c9-9d35-40bd-a357-669ca22cea7d","added_by":"auto","created_at":"2025-10-14 06:02:09","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":3454728,"visible":true,"origin":"","legend":"\u003cp\u003eTEM images of the in situ MoP, MoO\u003csub\u003ex\u003c/sub\u003e, WP, and WO\u003csub\u003ex\u003c/sub\u003e. The catalysts were obtained \u003cem\u003ein situ\u003c/em\u003e during the hydroprocessing of a mixture of phenol, hydroquinone and catechol at 300\u0026nbsp;°C, 5 MPa H\u003csub\u003e2\u003c/sub\u003e, 4 h.\u003c/p\u003e","description":"","filename":"Figure2.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/cf3ec12b24745cdd04d7b4cc.jpg"},{"id":93459141,"identity":"141ffb23-61c3-4fa5-ad86-29b76dac3e04","added_by":"auto","created_at":"2025-10-14 05:54:08","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":678719,"visible":true,"origin":"","legend":"\u003cp\u003eThe proposed transformations of hydroquinone and catechol using in situ MoO\u003csub\u003ex\u003c/sub\u003e, WO\u003csub\u003ex\u003c/sub\u003e, MoP, and WP. DDO – direct deoxygenation; HYD – hydrogenation; I – isomerization.\u003c/p\u003e","description":"","filename":"Figure3.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/42b849f515f355f4f40f6d10.jpg"},{"id":93459840,"identity":"34caf957-8c45-4db8-a8f4-15b07c5f23b1","added_by":"auto","created_at":"2025-10-14 06:02:09","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1580171,"visible":true,"origin":"","legend":"\u003cp\u003eThe results of\u003cstrong\u003e \u003c/strong\u003ehydroquinone and catechol hydroprocessing using in situ formed MoO\u003csub\u003ex\u003c/sub\u003e, WO\u003csub\u003ex\u003c/sub\u003e, MoP, and WP catalysts.\u003c/p\u003e","description":"","filename":"Figure4.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/c90dc50c4d7a189a0265a826.jpg"},{"id":93459117,"identity":"e0385921-bc9a-4e2a-87b6-e457da43e4e0","added_by":"auto","created_at":"2025-10-14 05:54:05","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1590797,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic illustration of hydroquinone and catechol HDO over different active sites of molybdenum and tungsten phosphide and oxide based catalysts.\u003c/p\u003e","description":"","filename":"Figure5.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/70617c7a8c76283c22066bf1.jpg"},{"id":93459164,"identity":"8612713f-877d-4809-b62b-640bef8e8072","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":623168,"visible":true,"origin":"","legend":"\u003cp\u003eHydroprocessing of\u003cstrong\u003e \u003c/strong\u003ephenol, catechol, and hydroquinone mixture at 300 °C, 5 MPa, 4 h.\u003c/p\u003e","description":"","filename":"Figure6.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/14f0a44df7b3a6e7c3b98299.jpg"},{"id":93460864,"identity":"abc3d619-3e0a-4843-9f71-0fe3cde9e4d5","added_by":"auto","created_at":"2025-10-14 06:18:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":10865152,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/cb822271-1577-44a2-a8ff-2ea81fa0bfea.pdf"},{"id":93460863,"identity":"a1e60e95-c40f-497b-9a14-e4684d27aee0","added_by":"auto","created_at":"2025-10-14 06:18:10","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":3355180,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/9011a883f6bca8bf49eb0e1d.docx"},{"id":93459166,"identity":"1886e837-df06-497f-aa5a-6bcd9fdb12ee","added_by":"auto","created_at":"2025-10-14 05:54:10","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":721437,"visible":true,"origin":"","legend":"","description":"","filename":"Graphicalabstract.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7609053/v1/226a2c8faf926f2339ebd055.jpg"}],"financialInterests":"No competing interests reported.","formattedTitle":"Development of selective catalysts for hydroprocessing of phenol production by-products — hydroquinone and catechol","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePhenol is one of the most important industrial chemicals, which is widely used for the synthesis of phenol resins, bisphenol A, epoxy resins, etc. The conventional methods for phenol production, primarily the cumene process, have several limitations, such as high energy consumption, low yield of phenol, equimolar amounts of a by-product (acetone), potential environmental concerns [1\u0026thinsp;\u0026minus;\u0026thinsp;4]. Currently, the development of green and efficient approaches for chemical synthesis, including for the production of phenol, is one of the crucial tasks of the scientific community. Direct transformation of arenes to phenol \u003cem\u003evia\u003c/em\u003e hydroxylation reaction using various oxidants (H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, O\u003csub\u003e2\u003c/sub\u003e, N\u003csub\u003e2\u003c/sub\u003eO) is a one-step alternative method for environmentally friendly synthesis of phenol [1, 3\u0026thinsp;\u0026minus;\u0026thinsp;5]. However, the formation of by-products (hydroquinone and catechol) during the oxidation of phenol is the major disadvantage of this process [3, 6\u0026thinsp;\u0026minus;\u0026thinsp;9]. Additionally, hydroquinone, catechol and other phenol derivatives can also be formed by lignin depolymerization [10\u0026thinsp;\u0026minus;\u0026thinsp;13].\u003c/p\u003e\u003cp\u003eThe selective hydroprocessing of hydroquinone and catechol towards phenol, in turn, can significantly increase the yield of the target product. However, most of the catalysts proposed in the literature promote the direct hydrogenation of dihydroxybenzenes (hydroquinone and catechol) to dihydroxycyclohexanes, and the selectivity for phenol was low [11, 14\u0026thinsp;\u0026minus;\u0026thinsp;16]. For instance, Li et al. studied the performance of the series of Ru-based catalysts modified by alkaline earth metals in the hydrogenation of hydroquinone [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The major reaction product was 1,4-dihydroxycyclohexane, the selectivity for which reached up to 99.6% (150\u0026deg;C, 5 MPa, 3 h). Moreover, the use of Ni-based catalysts promoted the hydrogenation reaction as dominant in the hydroprocessing of hydroquinone. The highest selectivity for 1,4-dihydroxycyclohexane was 96.7% over a Ni\u0026ndash;Sr/γ-Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e catalyst at 99.2% conversion [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Song et al. explored the activity of Ni-containing unsupported and supported on HZSM-5 catalysts in the conversion of phenol, catechol, and guaiacol in the aqueous phase [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. For catechol, it was shown that initially the deoxygenation of the aryl C-O bond and hydrogenation of the aromatic ring occurred in parallel. However, then the hydrogenation reaction dominated, and, as a result, 1,2-dihydroxycyclohexane was formed with around 85% yield after 120 min over Ni/HZSM-5 (200\u0026deg;C, 30 bar of H\u003csub\u003e2\u003c/sub\u003e).\u003c/p\u003e\u003cp\u003eIn our previous studies, transition metal compound (oxide, phosphide) based catalysts were extensively studied in the hydroprocessing of various oxygen-containing substrates [17\u0026thinsp;\u0026minus;\u0026thinsp;19]. The objective of this work is to explore the possibility of the selective transformation of hydroquinone and catechol to phenol using \u003cem\u003ein situ\u003c/em\u003e formed transition metal phosphides and oxides (MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e, and WO\u003csub\u003ex\u003c/sub\u003e) in the autoclave reactor. These catalysts are characterized by high catalytic activity in hydrodeoxygenation (HDO) reactions, as well as lower cost compared to traditional hydroprocessing catalysts (noble metal containing catalysts). The proposed \u003cem\u003ein situ\u003c/em\u003e method for the synthesis of transition metal phosphides and oxides is not accompanied by the release of harmful substances into the atmosphere. Moreover, such approach can significantly simplify the process due to the absence of a separate stage of catalyst synthesis. Furthermore, \u003cem\u003ein situ\u003c/em\u003e formed transition metal oxides and phosphides have been shown to be reused without significant loss of activity.\u003c/p\u003e"},{"header":"2. Experimental section","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Materials\u003c/h2\u003e\u003cp\u003eThe chemicals used for \u003cem\u003ein situ\u003c/em\u003e catalyst synthesis are molybdenum hexacarbonyl (LLC \u0026laquo;Redkino experimental plant\u0026raquo;, Redkino, Russia, 36.5\u0026ndash;37.5 wt% of Mo), tungsten hexacarbonyl (LLC \u0026laquo;Redkino experimental plant\u0026raquo;, Redkino, Russia, 51\u0026ndash;52% wt% of W), trioctylphosphine (Sigma-Aldrich, USA, 97%). Phenol (Reachem, Russia, pure), catechol (Alfa Aesar, United Kingdom, 99%), and hydroquinone (Reachem, Russia, pure) were employed as substrates, dodecane (Component-reaktiv, Russia, \u0026gt;\u0026thinsp;99%) was used as a solvent. Ethyl acetate (Component-reaktiv, Russia, 99.7%) was used to remove unreacted substrates. Acetone (Component-reaktiv, Russia, \u0026gt;\u0026thinsp;99.5%) and petroleum ether 40/70 (Component-reaktiv, Russia, tech.) were used for catalyst washing.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Catalytic tests\u003c/h2\u003e\u003cp\u003eIt should be noted that all catalysts were formed \u003cem\u003ein situ\u003c/em\u003e in the reaction medium without an additional stage. Generally, a mixture of 0.1 g of substrate, 1.5 g of solvent, and precursors was placed into the autoclave reactor. Mo(CO)\u003csub\u003e6\u003c/sub\u003e and W(CO)\u003csub\u003e6\u003c/sub\u003e were used as precursors for \u003cem\u003ein situ\u003c/em\u003e synthesis of MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e catalysts. In the case of MoP and WP, a mixture of metal carbonyls and tryoctylphosphine was used (the molar ratio of M/P\u0026thinsp;=\u0026thinsp;1). The molar ratio of substrate/metal was 5. All the experiments were conducted at a constant stirring speed of 900 rpm. The experiments were carried out at 300 and 350\u0026deg;C, 5 MPa H\u003csub\u003e2\u003c/sub\u003e, for 4 h. After cooling the reactor to the ambient temperature, ethyl acetate was added to dissolve unreacted substrates, and the liquid reaction products were separated by centrifugation. The catalyst samples were washed with various solvents (acetone and petroleum ether 40/70) and dried in an Ar atmosphere.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Products analysis\u003c/h2\u003e\u003cp\u003eThe liquid products were identified using a gas chromatography\u0026ndash;mass spectrometer (Thermo Scientific ISQ 7000 GC-MS) equipped with a capillary column (Restek 5XI-17SIL MS CAP, 30 m \u0026times; 0.25 mm \u0026times; 0.25 \u0026micro;m). A gas chromatograph (Crystallux 4000 M) equipped with a flame ionization detector and capillary column (Optima-1, 25 m \u0026times; 0.32 mm \u0026times; 0.35 \u0026micro;m) was used for quantitative analysis of the reaction products.\u003c/p\u003e\u003cp\u003eThe conversion of substrates and product selectivity were calculated using the following equations:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:\\text{C}\\text{o}\\text{n}\\text{v}\\text{e}\\text{r}\\text{s}\\text{i}\\text{o}\\text{n}\\:\\left(\\text{%}\\right)=\\:\\frac{\\text{m}\\text{o}\\text{l}\\text{e}\\:\\text{o}\\text{f}\\:\\text{s}\\text{u}\\text{b}\\text{s}\\text{t}\\text{r}\\text{a}\\text{t}\\text{e}\\:\\text{c}\\text{o}\\text{n}\\text{s}\\text{u}\\text{m}\\text{e}\\text{d}}{\\text{i}\\text{n}\\text{i}\\text{t}\\text{i}\\text{a}\\text{l}\\:\\text{m}\\text{o}\\text{l}\\text{e}\\:\\text{o}\\text{f}\\:\\text{s}\\text{u}\\text{b}\\text{s}\\text{t}\\text{r}\\text{a}\\text{t}\\text{e}}\\times\\:100\\%$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$\\:\\mathbf{S}\\mathbf{e}\\mathbf{l}\\mathbf{e}\\mathbf{c}\\mathbf{t}\\mathbf{i}\\mathbf{v}\\mathbf{i}\\mathbf{t}\\mathbf{y}\\:\\left(\\mathbf{\\%}\\right)=\\:\\frac{\\mathbf{m}\\mathbf{o}\\mathbf{l}\\mathbf{e}\\:\\mathbf{o}\\mathbf{f}\\:\\mathbf{p}\\mathbf{r}\\mathbf{o}\\mathbf{d}\\mathbf{u}\\mathbf{c}\\mathbf{t}}{\\sum\\:\\mathbf{m}\\mathbf{o}\\mathbf{l}\\mathbf{e}\\mathbf{s}\\:\\mathbf{o}\\mathbf{f}\\:\\mathbf{a}\\mathbf{l}\\mathbf{l}\\:\\mathbf{p}\\mathbf{r}\\mathbf{o}\\mathbf{d}\\mathbf{u}\\mathbf{c}\\mathbf{t}\\mathbf{s}}\\times\\:100\\varvec{\\%}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4. Catalyst characterization\u003c/h2\u003e\u003cp\u003eThe powder X-ray diffraction (XRD) was performed with a Rigaku Miniflex-600 diffractometer (Rigaku Corporation, Tokyo, Japan). XRD data were recorded using Cu-Kα radiation (40 kV, 15 mA, Ni-Kβ filter) in the 2θ range 10\u0026ndash;80\u0026deg; at a scan rate of 0.5\u0026deg;/min. The PDF-2 ICDD database was used for phase identification with the help of integrated X-ray powder diffraction software (PDXL: Rigaku Diffraction Software).\u003c/p\u003e\u003cp\u003eX-ray photoelectron spectroscopy (XPS) profiles were collected by a PREVAC EA15 electron spectrometer with AlK\u003csub\u003eɑ\u003c/sub\u003e radiation (hν\u0026thinsp;=\u0026thinsp;1486.74 eV, 150 W) and deconvoluted using the CasaXPS program.\u003c/p\u003e\u003cp\u003eThe specimens for the transmission and scanning transmission electron microscopy (TEM and STEM, correspondingly) were prepared by deposition of catalytic particles on copper grid coated with ultra-thin carbon film TEM/STEM were performed in a Osiris TEM/STEM (Thermo Fisher Scientific, USA) equipped with an energy dispersive X-ray (EDX) Super X spectrometer (ChemiSTEM, Bruker, USA) and high angle annular dark field (HAADF) detector (Fischione, USA) operating at an acceleration voltage of 200 kV.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1. Catalyst characterization\u003c/h2\u003e\u003cp\u003eThe catalysts (MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e, and WO\u003csub\u003ex\u003c/sub\u003e) formed \u003cem\u003ein situ\u003c/em\u003e during the hydroprocessing of a mixture of phenol, hydroquinone, and catechol (300\u0026deg;C, 5 MPa H\u003csub\u003e2\u003c/sub\u003e, 4 h) were studied using various physico-chemical methods. Metal carbonyls (Mo(CO)\u003csub\u003e6\u003c/sub\u003e and W(CO)\u003csub\u003e6\u003c/sub\u003e) were used as precursors for the \u003cem\u003ein situ\u003c/em\u003e synthesis of MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e catalysts. \u003cem\u003eIn situ\u003c/em\u003e MoP and WP were prepared using metal carbonyls and trioctylphosphine. The possible pathways for the formation of transition metal (Mo, W) oxides and phosphides were discussed in detail in our previous study [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e shows the XRD patterns of the MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e, and WO\u003csub\u003ex\u003c/sub\u003e. \u003cem\u003eIn situ\u003c/em\u003e MoP and MoO\u003csub\u003ex\u003c/sub\u003e are amorphous; that was also observed in the previous work. \u003cem\u003eIn situ\u003c/em\u003e WO\u003csub\u003ex\u003c/sub\u003e is crystalline and contains the W\u003csub\u003e18\u003c/sub\u003eO\u003csub\u003e49\u003c/sub\u003e phase (PDF #71\u0026thinsp;\u0026minus;\u0026thinsp;2450). The diffraction peaks at the 2θ of 23.5\u0026deg; and 48.1\u0026deg; are attributed to the (010) and (020) lattice planes in W\u003csub\u003e18\u003c/sub\u003eO\u003csub\u003e49\u003c/sub\u003e. The broad diffraction reflection related to the W\u003csub\u003e18\u003c/sub\u003eO\u003csub\u003e49\u003c/sub\u003e phase was also observed in the diffractogram of the \u003cem\u003ein situ\u003c/em\u003e WP catalyst. One of the possible routes of molybdenum and tungsten phosphide formation can proceed through the formation of oxides and their subsequent phosphidation to metal phosphides [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. According to the above discussion, \u003cem\u003ein situ\u003c/em\u003e formed WP catalyst is a mixture of amorphous WP and some amounts of W\u003csub\u003e18\u003c/sub\u003eO\u003csub\u003e49\u003c/sub\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe XPS method was applied to investigate the surface composition of the catalysts studied. The full XPS data, including the values of binding energy for all catalysts, is presented in Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e (MoP, WP) and Table S2 (MoO\u003csub\u003ex\u003c/sub\u003e, WO\u003csub\u003ex\u003c/sub\u003e). The deconvoluted spectra of MoP and WP in Mo 3d and W 4f regions, respectively, include three doublets related to the following oxidation states: M\u003csup\u003eδ+,\u003c/sup\u003e M\u003csup\u003e4+\u003c/sup\u003e, and M\u003csup\u003e6+\u003c/sup\u003e (M\u0026thinsp;=\u0026thinsp;Mo or W). The M\u003csup\u003eδ+\u003c/sup\u003e (M\u0026thinsp;=\u0026thinsp;Mo or W) peaks are attributed to molybdenum and tungsten phosphides, while the peaks of M\u003csup\u003e4+\u003c/sup\u003e and M\u003csup\u003e6+\u003c/sup\u003e can be assigned to their oxides and phosphates [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The P 2p spectra of MoP and WP catalysts are presented by two doublets related to P\u003csup\u003eδ\u0026minus;\u003c/sup\u003e in the corresponding phosphides and P\u003csup\u003e5+\u003c/sup\u003e in phosphates. The estimated surface content of M\u003csup\u003eδ+\u003c/sup\u003e was 5% for MoP and 8% for WP, while the content of P\u003csup\u003eδ\u0026minus;\u003c/sup\u003e was 10% for MoP and 13% for WP. The presence of P\u003csup\u003e5+\u003c/sup\u003e is due to the surface oxidation of the samples. The metal sites (M\u003csup\u003eδ+)\u003c/sup\u003e, as well as Br\u0026oslash;nsted (P-OH) and Lewis (M\u003csup\u003en+\u003c/sup\u003e) acid sites, are the crucial characteristics in the catalytic performance of transition metal phosphides. The doublets of M\u003csup\u003en+\u003c/sup\u003e (n\u0026thinsp;=\u0026thinsp;4, 5, 6) in the Mo 3d and W 4f regions in the spectra of MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e are associated with their oxides. The presence of Mo\u003csup\u003e5+\u003c/sup\u003e and W\u003csup\u003e5+\u003c/sup\u003e directly indicates the formation of oxygen vacancies (OVs), which are produced \u003cem\u003evia\u003c/em\u003e the partial reduction of metal oxides in a hydrogen atmosphere [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Moreover, for MoO\u003csub\u003ex\u003c/sub\u003e, the content of Mo\u003csup\u003e5+\u003c/sup\u003e (16%) is higher compared to the content of W\u003csup\u003e5+\u003c/sup\u003e (10%) in WO\u003csub\u003ex\u003c/sub\u003e. The O 1s spectra for molybdenum and tungsten oxides were deconvoluted into three peaks corresponding to their oxides (M-O), OVs, and M-OH groups. M-OH are formed by the adsorption of water generated during HDO reactions. According to the XPS results in the O 1s region, the content of OVs for MoO\u003csub\u003ex\u003c/sub\u003e (17%) is also higher than for WO\u003csub\u003ex\u003c/sub\u003e (11%). The content of OVs in transition metal oxides primarily influences the catalytic performance in HDO reactions.\u003c/p\u003e\u003cp\u003eThe morphology and crystal structure of \u003cem\u003ein situ\u003c/em\u003e obtained MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e, and WO\u003csub\u003ex\u003c/sub\u003e catalysts was characterized by TEM including high resolution (HR) TEM (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Similar to the XRD results, \u003cem\u003ein situ\u003c/em\u003e MoP and WP samples are amorphous, but a number of particles and their agglomerates reveal crystalline structure and that was observed on HRTEM images. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea, the observed lattice spacing of 0.204 nm corresponds to the (101) interplane distance of MoP (PDF #24\u0026ndash;771), and the lattice spacing of 0.292 nm belongs to the (011) of WP (PDF #29-1364). The difference between XRD and HRTEM results may be attributed to the small dimension of crystalline particles. As displayed in Fig. S2, the metal (Mo or W), P, and O were uniformly distributed in the particles of MoP and WP samples. The presence of oxygen atoms may be attributed to the partial oxidation of phosphides to phosphates or to the existence of metal oxides that were not fully converted to phosphides during the phosphidation process. \u003cem\u003eIn situ\u003c/em\u003e MoO\u003csub\u003ex\u003c/sub\u003e catalyst represents agglomerates of particles (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). According to the HRTEM image of \u003cem\u003ein situ\u003c/em\u003e MoO\u003csub\u003ex\u003c/sub\u003e, the two lattice spacings of 0.218 and 0.286 nm are attributed to the (101) of MoO\u003csub\u003e2\u003c/sub\u003e (PDF #50\u0026ndash;739) and to the (212) of Mo\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e11\u003c/sub\u003e (PDF #73-1538). \u003cem\u003eIn situ\u003c/em\u003e WO\u003csub\u003ex\u003c/sub\u003e contains agglomerates of particles surrounded by nanorods. The lattice spacing of 0.378 nm was found in the nanorods, which match to the (010) of W\u003csub\u003e18\u003c/sub\u003eO\u003csub\u003e49\u003c/sub\u003e (PDF #71-2450). Additionally, the lattice spacing of 0.236 nm was observed, which fits to the (002) crystal plane of WO\u003csub\u003e2\u003c/sub\u003e (PDF #71\u0026ndash;614). As shown in the [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], the \u003cem\u003ein situ\u003c/em\u003e transformations of metal carbonyls (Mo(CO)\u003csub\u003e6\u003c/sub\u003e and W(CO)\u003csub\u003e6\u003c/sub\u003e) during HDO reactions undergo through following stages: Mo(CO)\u003csub\u003e6\u003c/sub\u003e \u0026rarr; MoO\u003csub\u003e3\u003c/sub\u003e \u0026rarr; Mo\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e11\u003c/sub\u003e \u0026rarr; MoO\u003csub\u003e2\u003c/sub\u003e and W(CO)\u003csub\u003e6\u003c/sub\u003e \u0026rarr; WO\u003csub\u003e3\u003c/sub\u003e \u0026rarr; W\u003csub\u003e18\u003c/sub\u003eO\u003csub\u003e49\u003c/sub\u003e \u0026rarr; WO\u003csub\u003e2\u003c/sub\u003e, respectively. In the present study, the reaction conditions were moderate (300\u0026deg;C, 5 MPa H\u003csub\u003e2\u003c/sub\u003e, 4 h), and the complete reduction into MoO\u003csub\u003e2\u003c/sub\u003e and WO\u003csub\u003e2\u003c/sub\u003e was not achieved. The uniform distribution of metal and oxygen atoms can be observed in the elemental maps of \u003cem\u003ein situ\u003c/em\u003e MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e samples (Fig. S3).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.2. Catalytic tests\u003c/h2\u003e\u003cp\u003e\u003cem\u003eHydroprocessing of hydroquinone and catechol\u003c/em\u003e\u003c/p\u003e\u003cp\u003eHydroprocessing of hydroquinone and catechol was studied at 300 and 350\u0026deg;C (5 MPa, 4 h) using \u003cem\u003ein situ\u003c/em\u003e formed metal (Mo or W) oxides and phosphides. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the proposed scheme of catechol and hydroquinone transformations using catalysts studied. Initially, phenol is formed \u003cem\u003evia\u003c/em\u003e direct deoxygenation (DDO) of both dihydroxybenzenes. The further conversion of phenol can proceed by its hydrogenation (HYD) into cyclohexanol or DDO to benzene [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Cyclohexene and cyclohexanol were not detected among the reaction products; however, these compounds can be intermediates in the stepwise pathway leading to the formation of cyclohexane [16, 28\u0026thinsp;\u0026minus;\u0026thinsp;30]. Hydrogenation of cyclohexene produced cyclohexane and methylcyclopentane, which can be converted into each other \u003cem\u003evia\u003c/em\u003e isomerization [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe full conversion of both substrates was achieved in the presence of \u003cem\u003ein situ\u003c/em\u003e MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e. In the case of \u003cem\u003ein situ\u003c/em\u003e MoP and WP, the conversion of hydroquinone and catechol was 92\u0026thinsp;\u0026minus;\u0026thinsp;98% (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The hydroprocessing of hydroquinone using MoO\u003csub\u003ex\u003c/sub\u003e at 300\u0026deg;C produces a mixture of benzene, cyclohexane, and phenol. As the temperature increased from 300 to 350\u0026deg;C the selectivity for phenol decreased from 30 to 1%, and the selectivity for benzene increased from 23 to 40%, which is associated with the occurrence of phenol DDO to benzene (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The selectivity for methylcyclopentane rose from 1 to 22%, and the selectivity for cyclohexane decreased from 46 to 36% with an increase in the reaction temperature from 300 to 350\u0026deg;C. This result can be due to isomerization of cyclohexane to methylcyclopentane. For MoP, an increase in reaction temperature from 300 to 350\u0026deg;C resulted in a decrease in phenol selectivity from 83% to 62%. Increasing the reaction temperature promoted DDO of phenol to benzene and further formation of cyclohexane. In the case of hydroquinone hydroprocessing using WO\u003csub\u003ex\u003c/sub\u003e, with an increase in temperature from 300 to 350\u0026deg;C, the selectivity for phenol significantly decreased from 75 to 31%, which is due to its conversion to benzene (selectivity 42%) and to methylcyclopentane (selectivity 23%). For WP, the selectivity for phenol maintained high selectivity for phenol even with an increase in temperature and was 80% at 300\u0026deg;C and 95% at 350\u0026deg;C (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eFurthermore, hydroprocessing of catechol was studied at 300 and 350\u0026deg;C. Phenol was the major reaction product of catechol conversion over WO\u003csub\u003ex\u003c/sub\u003e (59%), WP (90%), and MoP (64%) catalysts at 300\u0026deg;C. For WP and MoP, the selectivity for phenol decreased to 76% and 43% at 350\u0026deg;C, respectively. However, in the case of WO\u003csub\u003ex\u003c/sub\u003e, as the reaction temperature increased to 350\u0026deg;C, the selectivity for products such as benzene, cyclohexane, and methylcyclopentane significantly increased, and the selectivity for phenol decreased to 25%. The use of MoO\u003csub\u003ex\u003c/sub\u003e as a catalyst in the hydroprocessing of catechol resulted in the formation of cyclohexane (68%) and benzene (30%). When the reaction temperature increased from 300 to 350\u0026deg;C, the selectivity for cyclohexane decreased to 45% due to its conversion to methylcyclopentane. As shown for another oxygen-containing substrate, guaiacol, the high selectivity in the partial HDO of guaiacol to phenol was retained at the temperatures below 300\u0026deg;C using \u003cem\u003ein situ\u003c/em\u003e MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Generally, the elimination of the OH-group in the ortho-position with phenol formation occurred faster than in the para-position [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Some authors also noted the higher adsorbability of catechol compared to hydroquinone [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the schematic illustration of hydroquinone and catechol HDO over different active sites of \u003cem\u003ein situ\u003c/em\u003e formed metal (Mo or W) phosphides and oxides. In the case of MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e, DDO reactions occur over OVs and acid sites (M\u003csup\u003en+\u003c/sup\u003e and M\u003csup\u003en+\u003c/sup\u003e-OH). Moreover, OVs are also considered as active sites involved in HYD [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. In the case of MoP and WP, metal sites (M\u003csup\u003eδ+\u003c/sup\u003e) are active in HYD reactions and Br\u0026oslash;nsted/Lewis acid sites (M\u003csup\u003en+\u003c/sup\u003e, M\u003csup\u003en+\u003c/sup\u003e-OH and P-OH) in DDO [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThus, MoP and WP are more selective in the partial deoxygenation of catechol and hydroquinone to phenol. The use of MoO\u003csub\u003ex\u003c/sub\u003e in the conversion of catechol and hydroquinone promoted the formation of methylcyclopentane, benzene, and cyclohexane. Their selectivity changed depending on the reaction temperature. WO\u003csub\u003ex\u003c/sub\u003e maintains the phenol selectivity of 59\u0026thinsp;\u0026minus;\u0026thinsp;75% at low temperature, but at 350\u0026deg;C selectivity for benzene, cyclohexane, and methylcyclopentane significantly increased.\u003c/p\u003e\u003cp\u003e\u003cem\u003eHydroprocessing of the hydroquinone and catechol mixture\u003c/em\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eIn situ\u003c/em\u003e MoO\u003csub\u003ex\u003c/sub\u003e, WO\u003csub\u003ex\u003c/sub\u003e, MoP, and WP were also tested in the hydroprocessing of a hydroquinone and catechol mixture at their different molar ratio (Cat/Hydr\u0026thinsp;=\u0026thinsp;1 and 2). The results are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. An increase of the Cat/Hydr molar ratio from 1 to 2 had an insignificant effect on conversion in the case of MoO\u003csub\u003ex\u003c/sub\u003e, WO\u003csub\u003ex\u003c/sub\u003e, and MoP catalysts. For WP, the conversion of substrates was 89% at the molar ratio of Cat/Hydr\u0026thinsp;=\u0026thinsp;2 and 70% at the Cat/Hydr\u0026thinsp;=\u0026thinsp;1. As was shown in the previous studies, the conversion of other oxygen-containing compounds (terephthalic acid, benzoic acid, p-methylbenzoic acid, guaiacol) using \u003cem\u003ein situ\u003c/em\u003e WP was lower compared to MoO\u003csub\u003ex\u003c/sub\u003e, WO\u003csub\u003ex\u003c/sub\u003e, MoP [17\u0026thinsp;\u0026minus;\u0026thinsp;19]. An increase in the molar ratio of catechol/hydroquinone also affected the selectivity for phenol. In the case of MoO\u003csub\u003ex\u003c/sub\u003e and MoP, the selectivity for phenol was 60% (MoO\u003csub\u003ex\u003c/sub\u003e) and 80% (MoP) at a Cat/Hydr\u0026thinsp;=\u0026thinsp;1, and decreased to 54% (MoO\u003csub\u003ex\u003c/sub\u003e) and 65% (MoP) at a Cat/Hydr\u0026thinsp;=\u0026thinsp;2. As shown for hydroprocessing of the individual compounds, DDO of catechol to phenol and the subsequent transformations to other products (benzene, cyclohexane, and methylcyclopentane) occurred faster than for hydroquinone. As a result, the selectivity for phenol was lower as the molar ratio of Cat/Hydr increased. The similar results were observed for tungsten-containing catalysts (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). For example, the selectivity for phenol was 91% at a Cat/Hydr\u0026thinsp;=\u0026thinsp;1 and 85% at a Cat/Hydr\u0026thinsp;=\u0026thinsp;2 using WP as a catalyst.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eInfluence of the catechol/hydroquinone molar ratio on the conversion of substrates and selectivity for phenol.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eCat/Hydr\u0026thinsp;=\u0026thinsp;1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e\u003cp\u003eCatalyst\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003eMoO\u003c/em\u003e\u003csub\u003e\u003cem\u003ex\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003eWO\u003c/em\u003e\u003csub\u003e\u003cem\u003ex\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eMoP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eWP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSelectivity for phenol, %\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e91\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eConversion, %\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003e87\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003e88\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003e86\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003e70\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eCat/Hydr\u0026thinsp;=\u0026thinsp;2\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e\u003cp\u003e\u003cb\u003eCatalyst\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eMoO\u003c/b\u003e\u003csub\u003e\u003cb\u003ex\u003c/b\u003e\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eWO\u003c/b\u003e\u003csub\u003e\u003cb\u003ex\u003c/b\u003e\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003eMoP\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003eWP\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSelectivity for phenol, %\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e85\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eConversion, %\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003e86\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003e89\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003e88\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003e89\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eHydroprocessing of the phenol, hydroquinone, and catechol mixture\u003c/em\u003e\u003c/p\u003e\u003cp\u003eAs was noted above, catechol and hydroquinone are by-products of the phenol production by oxidative method. Therefore, the selective conversion of the resulting by-products into phenol can increase the yield of the target product. Depending on the type of catalyst and the reaction conditions, the molar ratio of catechol/hydroquinone can vary in the range of 1\u0026thinsp;\u0026minus;\u0026thinsp;3 [36\u0026thinsp;\u0026minus;\u0026thinsp;39]. To study the possibility of increasing the yield of phenol, the activity of \u003cem\u003ein situ\u003c/em\u003e formed transition metal phosphide and oxide based catalysts was explored in the hydroprocessing of a mixture of phenol, hydroquinone, and catechol (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The molar ratio of phenol/hydroquinone/catechol was 7/2/1. The phenol content in the product mixture after the reaction changed following WP (88%)\u0026thinsp;\u0026gt;\u0026thinsp;MoP (75%)\u0026thinsp;\u0026gt;\u0026thinsp;WO\u003csub\u003ex\u003c/sub\u003e (55%)\u0026thinsp;\u0026gt;\u0026thinsp;\u0026gt;\u0026thinsp;MoO\u003csub\u003ex\u003c/sub\u003e (26%). MoO\u003csub\u003ex\u003c/sub\u003e is highly active in DDO reaction due to the fact that the main reaction was DDO of phenol to benzene (45%) and cyclohexane (16%). Because of less content of OVs in WO\u003csub\u003ex\u003c/sub\u003e compare to MoO\u003csub\u003ex\u003c/sub\u003e, the selectivity for full-deoxygenated products (benzene, cyclohexane, methylcyclopentane) was lower for WO\u003csub\u003ex\u003c/sub\u003e. In the case of MoP and WP, the hydroprocessing of catechol and hydroquinone towards phenol was predominant. Thus, it was shown that by-products (hydroquinone and catechol) formed during the production of phenol by the oxidative method can be selectively transformed into the target product \u0026ndash; phenol, using \u003cem\u003ein situ\u003c/em\u003e MoP and WP catalysts.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eFor the first time, \u003cem\u003ein situ\u003c/em\u003e formed MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e catalysts were tested in the hydroprocessing of hydroquinone, catechol, and their mixture. The formation of metal (Mo or W) phosphides and oxides was confirmed using various physico-chemical techniques (XRD, XPS, HRTEM). According to the HRTEM, \u003cem\u003ein situ\u003c/em\u003e formed molybdenum and tungsten phosphides are presented by MoP and WP phases. While \u003cem\u003ein situ\u003c/em\u003e obtained MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e catalysts are the mixtures of their various oxides: MoO\u003csub\u003e2\u003c/sub\u003e and Mo\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e11\u003c/sub\u003e in MoO\u003csub\u003ex\u003c/sub\u003e, W\u003csub\u003e18\u003c/sub\u003eO\u003csub\u003e49\u003c/sub\u003e and WO\u003csub\u003e2\u003c/sub\u003e in WO\u003csub\u003ex\u003c/sub\u003e. The differences between active sites over MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e, and WO\u003csub\u003ex\u003c/sub\u003e catalysts were shown by the XPS method.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eRegarding the results of the catalytic tests, MoP and WP are more selective catalysts in the partial HDO of catechol and hydroquinone into phenol than MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e. The highest selectivity for phenol was 83% and 95% over MoP and WP, respectively. Due to the high content of OVs, MoO\u003csub\u003ex\u003c/sub\u003e contributed to the full HDO of catechol and hydroquinone with the production of methylcyclopentane, benzene, and cyclohexane. Phenol was formed with 59\u0026thinsp;\u0026minus;\u0026thinsp;75% selectivity using WO\u003csub\u003ex\u003c/sub\u003e catalysts in HDO of both substrates. However, as temperature increased, the selectivity for phenol significantly decreased due to its transformation to benzene, cyclohexane, and methylcyclopentane. Moreover, the HDO of catechol occurred faster compared to hydroquinone.\u003c/p\u003e\u003cp\u003eIn addition, the hydroprocessing of a mixture of phenol, hydroquinone, and pyrocatechol (by-products of phenol production), was investigated in order to study the possibility of increasing the yield of the target product. The phenol content in the product mixture after the reaction changed as follows: WP (88%)\u0026thinsp;\u0026gt;\u0026thinsp;MoP (75%)\u0026thinsp;\u0026gt;\u0026thinsp;WO\u003csub\u003ex\u003c/sub\u003e (55%)\u0026thinsp;\u0026gt;\u0026thinsp;\u0026gt;\u0026thinsp;MoO\u003csub\u003ex\u003c/sub\u003e (26%). Thus, \u003cem\u003ein situ\u003c/em\u003e formed MoP and WP can be considered as the suitable catalysts for the selective HDO of hydroquinone and pyrocatechol towards phenol.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eHDO hydrodeoxygenation;\u003c/p\u003e\u003cp\u003eXRD powder X-ray diffraction;\u003c/p\u003e\u003cp\u003eXPS X-ray photoelectron spectroscopy;\u003c/p\u003e\u003cp\u003eHRTEM high-resolution transmission electron spectroscopy;\u003c/p\u003e\u003cp\u003eSTEM scanning transmission electron microscopy;\u003c/p\u003e\u003cp\u003eEDX energy-dispersive X-ray spectroscopy;\u003c/p\u003e\u003cp\u003eHAADF high angle annular dark field;\u003c/p\u003e\u003cp\u003eOVs oxygen vacancies;\u003c/p\u003e\u003cp\u003eDDO direct deoxygenation;\u003c/p\u003e\u003cp\u003eHYD hydrogenation.\u003c/p\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics and Consent to Participate\u003c/strong\u003e\u003cp\u003eThe authors are dedicated to maintaining the integrity of the scientific record and fully adhering to the Committee on Publication Ethics (COPE) guidelines during the preparation and submission of this paper.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eConsent for Publication\u003c/h2\u003e\u003cp\u003eAll authors have read and approved the final manuscript and consent to its publication in this journal.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCompeting Interest\u003c/strong\u003e\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThis research was funded by a grant from the Ministry of Science and Higher Education of the Russian Federation, grant number 075-15-2024-646.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eMariyam Mukhtarova: Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing, Validation, Formal analysis, Visualization, Investigation, Conceptualization. Maria A. Golubeva: Writing \u0026ndash; review \u0026amp; editing, Validation, Project administration, Supervision. Kirill I. Chernyshev: Formal analysis, Investigation. Alexander L. Vasiliev: Resources. Dzhamalutdin N. Ramazanov: Formal analysis. Oleg G. Sinyashin: Project administration, Funding acquisition. Anton L. Maximov: Conceptualization, Project administration, Supervision, Funding acquisition.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors thank Dr. Andrey L. Golovin from A.V. Shubnikov Institute of Crystallography RAS for the XRD analysis and Alexey A. Sadovnikov from TIPS RAS for the XPS analysis.This work was performed using the equipment of the Shared Research Center Analytical Center of Deep Oil Processing and Petrochemistry of A.V. Topchiev Institute of Petrochemical Synthesis RAS.Electron microscopic study was carried out within the framework of the state assignment of the National Research Center \"Kurchatov Institute\".\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eNo data was used for the research described in the article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eWang H, Wang C, Zhao M, Yang Y, Fang L, Wang Y (2018) H\u003csub\u003e5\u003c/sub\u003ePMo\u003csub\u003e10\u003c/sub\u003eV\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e40\u003c/sub\u003e anchor by OH of the Titania nanotubes: Highly efficient heterogeneous catalyst for the direct hydroxylation of benzene. Chem Eng Sci 177:399\u0026ndash;409. https://doi.org/10.1016/j.ces.2017.11.023\u003c/li\u003e\n\u003cli\u003eDai X, Zhou W, Yang S, Sun F A, Qian J, He M, Chen Q (2019) Microchannel process for phenol production via the cleavage of cumene hydroperoxide. Chem Eng Sci 199:398\u0026ndash;404. https://doi.org/10.1016/j.ces.2019.01.031 \u003c/li\u003e\n\u003cli\u003eNaranov E, Ramazanov D, Agliullin M, Sinyashin O, Maximov A (2024) Recent Advances in Aromatic Hydroxylation to Phenol and Hydroquinone Using H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e. Catalysts \u003cem\u003e14\u003c/em\u003e(12):930. https://doi.org/10.3390/catal14120930\u003c/li\u003e\n\u003cli\u003eWang W, Tang H, Jiang X, Huang F E, Ma Y (2019) Quinone\u0026ndash;amine polymers as metal\u0026ndash;free and reductant\u0026ndash;free catalysts for hydroxylation of benzene to phenol with molecular oxygen. Chem Commun \u003cem\u003e55\u003c/em\u003e(54):7772\u0026ndash;7775. https://doi.org/10.1039/C9CC03623G \u003c/li\u003e\n\u003cli\u003eWen G, Wu S, Li B, Dai C, Su DS (2015) Active sites and mechanisms for direct oxidation of benzene to phenol over carbon catalysts. Ang Chem Int Ed 54(13):4105\u0026ndash;4109. https://doi.org/10.1002/anie.201410093\u003c/li\u003e\n\u003cli\u003eYang JH, Sun G, Gao Y, Zhao H, Tang P, Tan J, Ma D (2013) Direct catalytic oxidation of benzene to phenol over metal\u0026ndash;free graphene\u0026ndash;based catalyst. Energy Environ Sci 6(3):793\u0026ndash;798. https://doi:10.1039/c3ee23623d \u003c/li\u003e\n\u003cli\u003eMolinari R, Poerio T (2010) Remarks on studies for direct production of phenol in conventional and membrane reactors. Asia\u0026ndash;Pac J Chem \u003cem\u003e5\u003c/em\u003e(1):191\u0026ndash;206. https://doi.org/10.1002/apj.369 \u003c/li\u003e\n\u003cli\u003eCenti G, Perathoner S (2009) One\u0026ndash;step H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e and phenol syntheses: examples of challenges for new sustainable selective oxidation processes. Catal Today 143(1\u0026ndash;2):145\u0026ndash;150. https://doi.org/10.1016/j.cattod.2008.09.032 \u003c/li\u003e\n\u003cli\u003eMakatsa TJ, Baloyi J, Ntho T, Masuku CM (2021) Catalytic wet air oxidation of phenol: Review of the reaction mechanism, kinetics, and CFD modeling. \u003cem\u003e \u003c/em\u003eCrit Rev Environ Sci Technol\u003cem\u003e \u003c/em\u003e51(17):1891\u0026ndash;1923. https://doi.org/10.1080/10643389.2020.1771886\u003c/li\u003e\n\u003cli\u003eWang Q, Shamzhy M, Heuson E, Trentesaux M., Marinova M, Addad A, Ordomsky VV (2024) Isomerization of dihydroxybenzenes over metal\u0026ndash;zeolite catalysts through the carbonaceous deposits. Chem Eng J 491:151956. https://doi.org/10.1016/j.cej.2024.151956\u003c/li\u003e\n\u003cli\u003eWang Y, Han C, Fu Z, Xiang M, Liu T, Zhang X, Wang Y (2025) Ultra\u0026ndash;small Ru nanoparticles supported on MgO modified Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e for efficient selective hydrogenation of hydroquinone to 1,4-cyclohexanediol. Appl Catal O: Open 206:207058. https://doi.org/10.1016/j.apcato.2025.207058\u003c/li\u003e\n\u003cli\u003ePan Z, Puente-Urbina A, Bodi A, van Bokhoven JA, Hemberger P (2021) Isomer\u0026ndash;dependent catalytic pyrolysis mechanism of the lignin model compounds catechol, resorcinol and hydroquinone. Chem Sci 12(9):3161\u0026ndash;3169. https://doi.org/10.1039/D1SC00654A\u003c/li\u003e\n\u003cli\u003eZhao C, He J, Lemonidou AA, Li X, Lercher JA (2011) Aqueous\u0026ndash;phase hydrodeoxygenation of bio\u0026ndash;derived phenols to cycloalkanes. J Catal 280(1):8\u0026ndash;16. http://dx.doi.org/10.1016/j.jcat.2011.02.001\u003c/li\u003e\n\u003cli\u003eLi H, Ji D, Li Y, Liang Y, Li GX (2015) Effect of alkaline earth metals on the liquid\u0026ndash;phase hydrogenation of hydroquinone over Ru\u0026ndash;based catalysts. Solid State Sci 50: 85\u0026ndash;90. https://doi.org/10.1016/j.solidstatesciences.2015.10.014\u003c/li\u003e\n\u003cli\u003eBai G, Li F, Fan X, Wang Y, Qiu M, Ma Z, Niu L (2012) Continuous hydrogenation of hydroquinone to 1,4-cyclohexanediol over alkaline earth metal modified nickel\u0026ndash;based catalysts. Catal Commun 17:126\u0026ndash;130. https://doi.org/10.1016/j.catcom.2011.10.026\u003c/li\u003e\n\u003cli\u003eSong W, Liu Y, Bar\u0026aacute;th E, Zhao C, Lercher JA (2015) Synergistic effects of Ni and acid sites for hydrogenation and C\u0026ndash;O bond cleavage of substituted phenols. Green Chem 17(2):1204\u0026ndash;1218. https://doi.org/10.1039/c4gc01798f \u003c/li\u003e\n\u003cli\u003eMukhtarova M, Golubeva M, Sadovnikov A, Maximov A (2023) Guaiacol to aromatics: Efficient transformation over \u003cem\u003ein situ\u003c/em\u003e-generated molybdenum and tungsten oxides. Catalysts 13(2):263. https://doi.org/10.3390/catal13020263\u003c/li\u003e\n\u003cli\u003eGolubeva MA, Mukhtarova M, Bugaev AL, Naranov ER (2022) \u003cem\u003eIn Situ\u003c/em\u003e Generated Dispersed Catalysts Based on Molybdenum and Tungsten Phosphides in Hydroprocessing of Guaiacol. Pet Chem 62(11):1300\u0026ndash;1307. https://doi.org/10.1134/S0965544122110019\u003c/li\u003e\n\u003cli\u003eMukhtarova M, Golubeva MA, Maximov A L (2025) Comparison of \u003cem\u003eIn Situ\u003c/em\u003e Formed Metal (Mo, W) Phosphides and Oxides in the Hydroprocessing of Used PET Bottles. ACS Sustainable Chem Eng\u003cem\u003e \u003c/em\u003e13(17):6307\u0026ndash;6317. https://doi.org/10.1021/acssuschemeng.5c00986\u003c/li\u003e\n\u003cli\u003eChen F, Zhao B, Sun M, Liu C, Shi Y, Yu Y, Zhang B (2022) Mechanistic insight into the controlled synthesis of metal phosphide catalysts from annealing of metal oxides with sodium hypophosphite. Nano Res 15(12):10134\u0026ndash;10141. https://doi.org/10.1007/s12274\u0026ndash;022\u0026ndash;4489\u0026ndash;x \u003c/li\u003e\n\u003cli\u003eLong B, Ma J, Song T, Song S, Tong Y, Wang X (2021) Intercalation\u0026ndash;type MoP and WP nanodots with abundant phase interface embedded in carbon microflower for enhanced Li storage and reaction kinetics. Electrochim Acta 365:137354. https://doi.org/10.1016/j.electacta.2020.137354\u003c/li\u003e\n\u003cli\u003ePeng S, Fu Q, Chen E, Li Y (2024) Coupling amorphous WO\u003csub\u003e3\u003c/sub\u003e with WP as a cocatalyst for efficient dye\u0026ndash;sensitizated photocatalytic hydrogen evolution. Int J of Hydrogen Energy 64:791\u0026ndash;797. https://doi.org/10.1016/j.ijhydene.2024.03.276\u003c/li\u003e\n\u003cli\u003eCiftyurek E, Li Z, Schierbaum K (2022) Adsorbed oxygen ions and oxygenies: their concentration and distribution in metal oxide chemical sensors and influencing role in sensitivity and sensing mechanisms. Sensors 23(1):29. https://doi.org/10.3390/s23010029 \u003c/li\u003e\n\u003cli\u003eCao S, Zeng Y, Li Y, Da K, Chen W, Yang J, Fan X (2025) The presence of Mo and O double vacancies in Bi\u003csub\u003e2\u003c/sub\u003eW\u003csub\u003e0.25\u003c/sub\u003eMo\u003csub\u003e0.75\u003c/sub\u003eO\u003csub\u003e6\u003c/sub\u003e solid solution promotes photogenerated charge separation and molecular oxygen activation for efficient removal of gaseous toluene under visible light. Sep Purif Technol 354:128958. https://doi.org/10.1016/j.seppur.2024.128958\u003c/li\u003e\n\u003cli\u003eMukhtarova M, Golubeva MA, Sadovnikov AA, Maximov AL (2024) Selective hydroprocessing of diphenyl ether into benzene over \u003cem\u003ein situ\u003c/em\u003e generated MoO\u003csub\u003ex\u003c/sub\u003e and WO\u003csub\u003ex\u003c/sub\u003e. Appl Catal B 351:123999. https://doi.org/10.1016/j.apcatb.2024.123999\u003c/li\u003e\n\u003cli\u003eMu W, Ben H, Ragauskas A, Deng Y (2013) Lignin pyrolysis components and upgrading\u0026mdash;technology review. Bioenergy Res 6(4):1183\u0026ndash;1204. http://dx.doi.org/10.1007/s12155\u0026ndash;013\u0026ndash;9314\u0026ndash;7\u003c/li\u003e\n\u003cli\u003eRanga C, L\u0026oslash;deng R, Alexiadis VI, Rajkhowa T, Bj\u0026oslash;rkan H, Chytil S, Thybaut JW (2018) Effect of composition and preparation of supported MoO\u003csub\u003e3\u003c/sub\u003e catalysts for anisole hydrodeoxygenation. Chem Eng J 335:120\u0026ndash;132. https://doi.org/10.1016/j.cej.2017.10.090\u003c/li\u003e\n\u003cli\u003eKirkwood K, Jackson SD (2021) Competitive hydrogenation and hydrodeoxygenation of oxygen-substituted aromatics over Rh/silica: catechol, resorcinol and hydroquinone. Top Catal 64(17):934\u0026ndash;944. https://doi.org/10.1007/s11244\u0026ndash;021\u0026ndash;01422\u0026ndash;3\u003c/li\u003e\n\u003cli\u003eXia H, Tan H, Cui H, Song F, Zhang Y, Zhao R, Li Z (2021) Tunable selectivity of phenol hydrogenation to cyclohexane or cyclohexanol by a solvent\u0026ndash;driven effect over a bifunctional Pd/NaY catalyst. Catal Sci Technol 11(5):1881\u0026ndash;1887. https://doi.org/10.1039/d0cy02188a\u003c/li\u003e\n\u003cli\u003eMao J, Zhao B, Zhou J, Zhang L, Yang F, Guo X, Zhang ZC (2019) Identification and characteristics of catalytic quad\u0026ndash;functions on Au/Anatase TiO\u003csub\u003e2\u003c/sub\u003e. ACS Catal 9(9):7900\u0026ndash;7911. http://dx.doi.org/10.1021/acscatal.9b02090\u003c/li\u003e\n\u003cli\u003eXu H, Li Z, Meng S, Jarvis J, Song H (2021) Highly selective skeletal isomerization of cyclohexene over zeolite-based catalysts for high\u0026ndash;purity methylcyclopentene production. Commun Chem 4(1):34. https://doi.org/10.1038/s42004\u0026ndash;021\u0026ndash;00472\u0026ndash;8\u003c/li\u003e\n\u003cli\u003eKirkwood K, Jackson SD (2020) Hydrogenation and hydrodeoxygenation of oxygen\u0026ndash;substituted aromatics over Rh/silica: Catechol, resorcinol and hydroquinone. Catalysts 10(5):584. https://doi.org/10.3390/catal10050584\u003c/li\u003e\n\u003cli\u003eSuresh S, Srivastava VC, Mishra IM (2012) Adsorption of catechol, resorcinol, hydroquinone, and their derivatives: a review. Int J Energy Environ Eng 3(1):32. https://doi.org/10.1186/2251\u0026ndash;6832\u0026ndash;3\u0026ndash;32\u003c/li\u003e\n\u003cli\u003eSaiz‐Poseu J, Mancebo‐Aracil J, Nador F. Busqu\u0026eacute; F, Ruiz‐Molina D (2019) The chemistry behind catechol‐based adhesion. Angew Chem Int Ed 58(3):696\u0026ndash;714. https://doi.org/10.1002/anie.201801063\u003c/li\u003e\n\u003cli\u003eJin F, Yang X, Yang J, Lei Y, Xu W, Jiang W, Li X (2024) Unraveling the influence of oxygen vacancies in MoO\u003csub\u003ex\u003c/sub\u003e catalysts on CO\u003csub\u003e2\u003c/sub\u003e hydrogenation. Chem Eng J 495:153333. https://doi.org/10.1016/j.cej.2024.153333\u003c/li\u003e\n\u003cli\u003eHocking MB, Intihar DJ (1985) Oxidation of phenol by aqueous hydrogen peroxide catalysed by ferric ion‐catechol complexes. \u003cem\u003e \u003c/em\u003eJ Chem Technol Biotechnol 35(7):365\u0026ndash;381. https://doi.org/10.1002/jctb.5040350706 \u003c/li\u003e\n\u003cli\u003eVilla AL, Caro CA, de Correa CM (2005) Cu\u0026ndash;and Fe\u0026ndash;ZSM\u0026ndash;5 as catalysts for phenol hydroxylation. J Mol Catal A Chem 228(1\u0026ndash;2):233\u0026ndash;240. https://doi.org/10.1016/j.molcata.2004.09.035\u003c/li\u003e\n\u003cli\u003eWu C, Kong Y, Gao F, Wu Y. Lu, Y, Wang J, Dong L (2008) Synthesis, characterization and catalytic performance for phenol hydroxylation of Fe\u0026ndash;MCM41 with high iron content. Microporous and Mesoporous Mater 113(1\u0026ndash;3):163\u0026ndash;170. https://doi.org/10.1016/j.micromeso.2007.11.013\u003c/li\u003e\n\u003cli\u003eAtoguchi T, Kanougi T, Yamamoto T, Yao S (2004) Phenol oxidation into catechol and hydroquinone over H\u0026ndash;MFI, H\u0026ndash;MOR, H\u0026ndash;USY and H\u0026ndash;BEA in the presence of ketone. J Mol Catal A Chem 220(2):183\u0026ndash;187. https://doi.org/10.1016/j.molcata.2003.10.026\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"catalysis-letters","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Catalysis Letters](https://link.springer.com/journal/10562)","snPcode":"10562","submissionUrl":"https://submission.springernature.com/new-submission/10562/3","title":"Catalysis Letters","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"phenol, catechol, hydroquinone, transition metal oxide, transition metal phosphide","lastPublishedDoi":"10.21203/rs.3.rs-7609053/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7609053/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe development of a selective catalyst for hydroprocessing of phenol production by-products (hydroquinone and catechol) is an important task for increasing the yield of the target product. In this study, the use of \u003cem\u003ein situ\u003c/em\u003e generated catalysts based on molybdenum and tungsten compounds (MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e, and WO\u003csub\u003ex\u003c/sub\u003e) was proposed for this goal. The performance of the catalysts was investigated in the hydroprocessing of each individual substrate (hydroquinone and catechol), as well as their mixture. It was shown that MoP and WP catalysts were more selective in the partial HDO of hydroquinone and catechol into phenol compared to their oxides, as a result, the selectivity for phenol was higher. The hydroprocessing of a mixture of phenol, hydroquinone, and catechol (the molar ratio of phenol/hydroquinone/catechol\u0026thinsp;=\u0026thinsp;7/2/1) was also explored using \u003cem\u003ein situ\u003c/em\u003e formed MoP, WP, MoO\u003csub\u003ex\u003c/sub\u003e, and WO\u003csub\u003ex\u003c/sub\u003e catalysts. The phenol content in the product mixture after the reaction changed in the following order: WP (88%)\u0026thinsp;\u0026gt;\u0026thinsp;MoP (75%)\u0026thinsp;\u0026gt;\u0026thinsp;WO\u003csub\u003ex\u003c/sub\u003e (55%)\u0026thinsp;\u0026gt;\u0026thinsp;\u0026gt;\u0026thinsp;MoO\u003csub\u003ex\u003c/sub\u003e (26%). Thus, \u003cem\u003ein situ\u003c/em\u003e formed MoP and WP can be considered as the suitable catalysts for the selective HDO of hydroquinone and catechol towards phenol.\u003c/p\u003e","manuscriptTitle":"Development of selective catalysts for hydroprocessing of phenol production by-products — hydroquinone and catechol","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-14 05:53:48","doi":"10.21203/rs.3.rs-7609053/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-13T20:12:16+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-11T18:31:38+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-05T19:14:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"225003686468604550156510501071243129928","date":"2025-10-01T16:00:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"15819178996248846516856527226663976626","date":"2025-09-29T20:45:58+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-29T20:21:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-26T04:11:59+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-26T04:11:06+00:00","index":"","fulltext":""},{"type":"submitted","content":"Catalysis Letters","date":"2025-09-13T18:29:08+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"catalysis-letters","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Catalysis Letters](https://link.springer.com/journal/10562)","snPcode":"10562","submissionUrl":"https://submission.springernature.com/new-submission/10562/3","title":"Catalysis Letters","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"29480851-c632-4574-86ad-293d42a93f02","owner":[],"postedDate":"October 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-11-28T00:08:17+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-14 05:53:48","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7609053","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7609053","identity":"rs-7609053","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}