Hydrothermal conversion of fructose to lactic acid and derivatives: Synergies of metal and acid/base catalysts

With increasing strict regulation on single-use plastics, lactic acid (LA) and alkyl lactates, as essential monomers for bio-degradable polylactic acid (PLA) plastic products, have gained worldwide attention in both academia and industry. While LA is still dominantly produced through fermentation processes from start, chemical synthesis from cellulosic biomass remains a grand challenge, owing to poor selectiv-ity in activating C-H and C-C bonds in sugar molecules. To our best knowledge, recent publications have been focused on hydrothermal conversion of glucose to LA, while this review summarizes the highlights on direct thermal conversion of fructose as starting material to LA and derivatives. In particular, the syn-ergies of metal/metal cations and acid/base catalysts will be critically revised on retro-aldol and dehydra-tion reactions. This work will provide insights into rational design of active and selective catalysts for the production of carboxylic acids from biomass feedstocks.(c) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.