Kinetic Modeling of Sorbitol Hydrogenolysis over Bimetallic RuRe/C Catalyst

Abstract

Sorbitol hydrogenolysis kinetics using bimetallic RuRe catalyst is reported based on multiple experiments in parallel batch slurry reactors (H2 pressure: 1.0–6.5 MPa, temperature: 473–503 K) to obtain concentration–time profiles. It is observed that RuRe/C bimetallic catalysts with Ca(OH)2 as a base promoter show significantly higher activity and selectivity toward liquid phase products such as 1,2-propanediol, lactic acid, ethylene glycol, and linear alcohols compared with monometallic Ru/C catalysts and other base promoters. It is further found that sorbitol hydrogenolysis initiates with dehydrogenation and subsequent C–C cleavage via retro-aldolization to form smaller molecules (C2–C4). Those smaller intermediates undergo dehydration, reorganization, and C–O cleavage to form C2–C3 acids, glycols, and linear alcohols as products, which are very similar to glycerol conversion chemistry. For the kinetic modeling, experimental data on concentration–time profiles were obtained using RuRe/C catalysts with Ca...