Kinetic modeling of Pt/C catalyzed aqueous phase glycerol conversion with in situ formed hydrogen

Detailed kinetic modeling of Pt/C catalyzed conversion of glycerol to lactic acid, glycols, and alcohols with in situ formed hydrogen is reported. Experimental concentration‐time profiles were obtained in a batch slurry reactor at different glycerol concentrations, nitrogen partial pressures, and NaOH concentrations in a temperature range of 130–160°C. Six different kinetic models were evaluated to describe the competing dehydrogenation, hydrogenolysis, dehydration, and CC cleavage reactions, and discriminated to fit the experimental data. It is found that a “dual‐similar‐site” mechanism involving alkali promoted dehydrogenation, on two adjacent Pt sites to affect CC and CO cleavage best describes the experimental data. The dehydrogenation reaction proceeds with a significantly lower activation barrier (E a  = 53 kJ/mol) compared with the noncatalytic hydrothermal conversion (E a  = 128 kJ/mol). The activation energy for glycerol hydrogenolysis on Pt/C catalyst without adding hydrogen is estimated to be 64 kJ/mol. © 2015 American Institute of Chemical Engineers AIChE J , 62: 1162–1173, 2016