Application of global analysis to linseed oil autoxidation

While the autoxidation of linseed oil has been extensively studied, the role of metal driers in catalyzing this process remains poorly understood. Previous studies have demonstrated that Fourier Transform Infrared spectroscopy (FT-IR) can be used to monitor the progress of autoxidation during linseed oil drying. Typically, studies have focused on a single absorption at 3010 cm-1 to determine the rate of autoxidation. In this study, FT-IR spectra of linseed oil during autoxidation were measured between 3800 and 700 cm-1 and fit to kinetic models using global analysis, which provides more robust fitting than prior methods. This study revealed that the drier catalyzed autoxidation process can be best modeled as an A → B → C type reaction, with B corresponding to a cis-trans conjugated intermediate previously identified in model complex studies. These kinetic models further revealed that for three Co driers the rate constants for the A → B and B → C reactions are identical within experimental error, suggesting both reactions share a rate limiting step.