Synthesis of earth abundant, non toxic mixed metal oxide catalysts for conversion of renewable carbon sources to drop-in fuels

Abstract

A 2-stage catalytic process for converting bio-oil oxygenates to higher value compounds for drop-in fuels was proposed. Ketonization using iron oxide catalysts prepared from red mud was implemented in a packed bed reactor system using model compounds. High levels of acetone (15-25 g/L), 2-butanone (~5 g/L), and cyclic ketones (9-13 g/L) were observed. Time-on-stream studies (8 h) indicated no measurable decline in conversion of acetol, formic acid, and levoglucosan, and only a 4% decline in acetic acid conversion. The effect of reduction pretreatment temperature on activity and surface properties of red mud was studied. Hydrogenation of ketonization products was conducted in continuous reactions using iron oxides and Pd-C catalysts. The best results were achieved in reactions using Pd-ACM (monoliths) at 180°C and 300 psi (H2), which converted ketones to alcohols at ~60-80%. Pd-C monoliths achieved higher space time yields and conversions compared to Pd-C granules.