KINETICS OF SEMI-BATCH OXIDATION OF BENZYL ALCOHOL TO BENZALDEHYDE BY USING SULFATED FE-TIO2 CATALYST

Abstract

Liquid phase semi-batch oxidation of benzyl alcohol to benzaldehyde was carried out by using a novel sulfated Fe-TiO₂ (designated as ICaT-3) solid catalyst by using hydrogen peroxide as oxidant and cetyltrimethylammonium bromide (CTAB) as phase transfer co-catalyst. ICaT-3 was characterized by Fourier-transform infrared, X-ray diffraction, thermogravimetry differential thermal analysis, surface area measurements, ammonia temperature-programmed desorption, scanning electron microscopy, and energy dispersive X-ray analysis. Under optimized reaction conditions, ICaT-3 gave 55% of benzyl alcohol conversion and 96% benzaldehyde selectivity, whereas pure TiO₂ gave only 14% of benzyl alcohol conversion. Effects of various parameters, such as speed of agitation, catalyst loading, CTAB loading, temperature, and catalyst reusability, were studied on the conversion of benzyl alcohol. It was observed that, with increasing the CTAB concentration benzyl alcohol, conversion increased up to 65%; whereas, without a phase transfer catalyst, only 4% conversion was observed. The reaction follows the Ishii-Venturello-type reaction mechanism and is first order with respect to benzyl alcohol. The value of the apparent activation energy is found to be 7.31 kcal/mol. The ICT-3 catalyst was found to be reusable.