Selective Oxidation of Glycerol to Dihydroxyacetone over a Pt–Bi/AC Commercial Catalyst: Reaction Kinetics and Modeling

The selective oxidation of glycerol to dihydroxyacetone (DHA) using a carbon-supported platinum–bismuth commercial catalyst (Pt–Bi/AC) is a promising route for glycerol valorization; however, the reaction network is complex. Kinetic studies were carried out in a batch reactor under base-free conditions. To improve kinetic parameter estimation, the network was decomposed into subnetworks by feeding reaction intermediates as reactants. A Langmuir–Hinshelwood–Hougen–Watson kinetic model was developed and successfully validated over the tested operating conditions (80–100 °C; 2.0–7.5 bar; 0.1–2.0 M glycerol; GLY/Pt = 250–1000 mol/mol), providing a valuable tool for process design, optimization, and scale-up. Glycerol oxidation to DHA exhibited a low activation energy (21 kJ mol−1) compared to DHA further oxidation (86 kJ mol−1). Glycerol and DHA exhibited weak adsorption on the catalyst surface, which favors high activity and selectivity. In contrast, the strong adsorption of glycolic and oxalic acids may hinder active sites, promoting overoxidation and catalyst deactivation.