Verification of propylene glycol preparation from glycerol via the acetol pathway by in situ hydrogenolysis

Abstract

Background: Propylene glycol (PG) is one value-added product that can be produced from glycerol through catalytic hydrogenolysis, which conventionally requires external supply of costly hydrogen. This study investigated PG preparation from glycerol through the acetol pathway by Raney nickel-catalyzed hydrogenolysis without an external hydrogen supply. Results: Experiments were designed to examine the glycerol conversion with specific reactant formulations. Thermodynamic analysis was also conducted on species at equilibrium to investigate the pathway from another angle. Conclusion: Acetol is the intermediate in glycerol conversion to PG and hydrogen is internally generated from reformation reactions. The reaction rate of acetol hydrogenolysis dictates the PG yield. PG would be further converted to ethanol through hydrogenolysis if the reaction time were extended.