The chemical hydrogenolysis of glycerol to produce propanediols is a promising strategy for the valorization of biomass. However, significant challenges remain due to the demanding reaction conditions and diverging requirements for the individual reaction steps.
The collaborative study between the Institute of Technical and Macromolecular Chemistry at the University of Hamburg, the Institute for Thermal Separation Processes, and the Institute of Process Systems Engineering (both at Hamburg University of Technology) investigates the kinetics of glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO) using a Ru–Cu/CNT catalyst. The results show no mass or heat transfer limitations. Experimental and kinetic modeling determined reaction orders of n (glycerol) = 1.1 and n (H2) = 0.12 up to 25 bar, with an activation energy of 150 kJ/mol for 1,2-PDO formation, while the undesired ethylene glycol pathway showed zero order and 65 kJ/mol activation energy. A two-step process, glycerol dehydration to acetol at 220 °C under nitrogen, followed by hydrogenation at 145 °C, achieves over 99% selectivity for both steps, showing great potential for the separate approach. Moreover, a kinetic model of the glycerol hydrogenolysis based on the experimentally derived reaction rates reliably reproduces the observed reaction behavior and parameters.
Piet Hassenstein, Daniel Niehaus, Nazanin Taherkhani, Jan-Dominik H. Krueger, Dorothea Voß, Dominique Lumpp, Baldur Schroeter, Leandros Paschalidis, Irina Smirnova, Mirko Skiborowski, Jakob Albert (2026). Boosting the Chemical Hydrogenolysis of Glycerol to 1,2-Propanediol to Almost Perfect Selectivity Using a Multifunctional Ru–Cu Carbon-Nanotube-Supported Catalyst. ACS Sustainable Chem. Eng. (in press).
