Structural and Vibrational Study of Molecular Interaction in a Ternary Liquid Mixture of Benzylamine, Ethanol and Benzene

Abstract The structural study of the non-covalent interactions in the ternary mixture of benzylamine (BA), ethanol and benzene have been attempted through Density Functional Theory (DFT) calculation. The optimized structure of monomers (BA, ethanol and benzene), BA dimer and their complexes (BA-benzene, BA-ethanol, BA-ethanol-benzene) and their interaction energy is used to describe the intermolecular interaction between the molecules. In addition to conventional H-bonding, the stability of the system is found to depend on several other interactions such as CH/π, NH/π, OH/π interaction. The Fourier Transform InfraRed (FTIR) spectroscopy technique is also used to study molecular interaction. An interpretation of the IR stretching bands based on the interactions is also provided. The variation in IR band position and intensity of spectra with change in concentration of the mixture shows that different kinds of interactions are presented in the mixture. The strength of these interactions varies with concentration. At lower concentration (x1=0.0), weak OH/π interaction between benzene and ethanol takes place while at other mole fraction N-H-----O, O-H------N, NH/π interaction is present between molecules.