Reaction engineering of the hydrogenolysis of liquid n-Alkanes: Comparison of flow and batch reaction systems

Currently there is much interest in developing catalysts for the hydrogenolysis of long-chain alkanes for use in the recycling and upcycling of waste polyolefins. Understanding how reactor configurations affect reactivity and product distributions for this class of reactions is equally important. To aid in this effort, here we report a study of the hydrogenolysis of the alkane, n-hexatriacontane (C₃₆H₇₄), over a Ru/SiO₂ catalyst in both batch and flow reactor configurations. For similar catalyst contact times and H₂ pressures, the C₃₆ hydrogenolysis rate was found to be significantly higher in the batch reactor compared to the flow reactor which can be attributed to H₂ bubbles forming inactive dry zones on the catalyst surface in the flow reactor which are less prevalent in the batch reactor. In both reactor systems the hydrogenolysis rate was found to be negative order in H₂ and that transport of the H₂ through the liquid phase to the catalyst surface was not rate limiting.