Kinetics of vanillin hydrodeoxygenation reaction in an organic solvent using a Pd/C catalyst

In this work, the kinetics of vanillin (VL) hydrodeoxygenation (HDO) reaction to creosol (CR) over a 10% Pd/C catalyst were studied in a batch autoclave operated at 318 - 338K, 1-3MPa H2 gas partial pressure, 35-65mM initial VL concentration (CVL,0) and 0.13-0.27kg/m3 catalyst loading. Experiments were carried out under negligible mass transfer interference which was verified by estimating the observable modulus, minimum stirring speed and maximum particle size. Additionally, the extent to which the products and acetic acid influences the reaction was examined. Two plausible Langmuir-Hinshelwood-Hougen-Watson (LHHW) models, competitive (Model I) and non-competitive (Model II) dissociative H2 adsorption were discriminated using criteria that R2 value greater than 99% indicates adequate fit to the experimental data. Model I emerged as the best fit with an R2 value greater than 99%. The estimated activation energy was 50.6 kJ/mol, enthalpy of adsorption for H2 28.9 kJ/mol and VL 32.5 kJ/mol.