Kinetic Study for Chemoselective Hydrogenation of Benzoic Acid to Benzyl Alcohol in a Batch Slurry Reactor using Ru-Sn/Al2O3 Catalyst

Abstract

Chemoselective hydrogenation of benzoic acid was carried out using Ru-Sn/Al₂O₃ catalyst at temperature and hydrogen pressure range of 473-513 K and 3.8-8.8 MPa, respectively. The Sn/Ru ratio in Ru-Sn/Al₂O₃ catalyst was 5. The initial rates for multiphasic hydrogenation reaction were observed to be first order with respect to catalyst loading, hydrogen partial pressure and benzoic acid. The initial rate data obtained were fitted to different rate equations based on Langmuir-Hinshelwood (L-H) type model and a rate model was obtained which predicted the rate of reaction with an error less than ± 5%. Rate model suggests two different type of active site on Ru-Sn/Al₂O₃ catalyst for hydrogenation of benzoic acid. The activation energy for hydrogenation of benzoic acid to benzyl alcohol using Ru-Sn/Al₂O₃ was found to be 81.64 kJ/mol.