Biomass-Based Production of Trimellitic and Trimesic Acids

Abstract

The production of industrial chemicals with renewable biomass feedstock holds potential to aid the world in pursuing a carbon-neutral society. Trimellitic and trimesic acids are important commodity chemicals in industry that are prepared by the oxidation of petroleum-derived trimethylbenzene. To reduce the dependence on the limited oil source, we develop a potential sustainable alternative towards trimellitic and trimesic acids using biomass-based 2-methyl-2,4-pentandiol (MPD), acrylate and crotonaldehyde as starting materials. The process for trimellitic acid includes dehydration/D-A reaction of MPD and acrylate, flow aromatization over Pd/C catalyst, hydrolysis and catalytic aerobic oxidation (60% overall yield). The challenging regioselectivity issue of D-A reaction was tackled by a matched combination of temperature and deep eutectic solvent ChCl/HCO2H. Crotonaldehyde could also participate in the reaction, followed by Pd/C-catalyzed decarbonylation/dehydrogenation and oxidation to provide trimesic acid in 54% overall yield.

Keywords: biomass, trimellitic acid, trimesic acid, deep eutectic solvent, dehydration/D-A reaction