Biomass-based production of trimellitic and trimesic acids

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 is tackled by a matched combination of temperature and deep eutectic solvent ChCl/HCO2H. Crotonaldehyde can also participate in the reaction, followed by Pd/C-catalyzed decarbonylation/dehydrogenation and oxidation to provide trimesic acid in 54% overall yield. Life cycle assessment implies that compared to conventional fossil process, our biomass-based routes present a potential in reducing carbon emissions. The manufacture of industrial chemicals with renewable biomass feedstock holds potential to aid the world in pursuing a carbon-neutral society. Trimellitic and trimesic acids are key chemicals in industry that are conventionally made by the oxidation of petroleum-derived trimethylbenzene. To reduce the reliance on the limited oil source, we develop a potential sustainable process for the production of trimellitic acid (60% overall yield) and trimesic acid (54% overall yield) with biomass-based 2-methyl-2,4-pentandiol, acrylate and crotonaldehyde as starting materials. [Display omitted] •An alternative process was developed to access trimellitic and trimesic acids with renewable feedstocks.•The process includes domino dehydration/D-A reaction flow aromatization over Pd/C and catalytic aerobic oxidation.•The regioselectivity issue of D-A reaction was tackled by a matched combination of temperature and solvent ChCl/HCO2H.