Kinetics of Aqueous-Phase Hydrogenation of Model Bio-oil Compounds over a Ru/C Catalyst

Aqueous-phase processing (APP) shows a lot of potential for the effective utilization of bio-oil. Water extraction, low-temperature hydrogenation of the water-soluble portion of bio-oil, and reforming (to H 2 ) or dehydration/hydrogenation (to C 1 –C 6 alkanes) are the three constituent steps of APP. In this work, two compounds representing the bio-oil aqueous fraction, viz., xylenol and maltol, were selected. Hydrogenation of these compounds in the aqueous phase was investigated in the 318–348 K range in a slurry reactor using a Ru/C catalyst. Kinetic data for the reactions with xylenol and maltol were collected in the chemical control regime and modeled using Langmuir–Hinshelwood kinetics. The dependency of the initial reaction rates upon H 2 partial pressure in the 0.69–2.07 MPa range was linear. The surface reaction between the chemisorbed reactants, viz., atomic hydrogen and substrate, was considered as rate-determining.