Advancing the synthesis of trimethylene carbonate: a high-yield green synthesis route

Trimethylene carbonate (TMC) is an innovative modifier for polylactic acid and a promising biodegradable polymer monomer with broad application potential. However, industrial production of TMC faces challenges such as high catalyst costs, safety issues, and environmental impacts. Enzymatic catalysis offers a potential alternative, but its low product yields have hindered progress. In this study, we introduce a novel synthesis route for TMC using bio-based 1,3-propanediol (1,3-PDO) and dimethyl carbonate (DMC) as substrates. This process involves lipase-catalyzed formation of the intermediate 3-hydroxypropyl methyl carbonate (P1), which is then cyclized to produce TMC. Notably, the by-product, C,C'-1,3-propanediyl C,C'-dimethyl ester (P2), reacts with 1,3-PDO to regenerate P1, further enhancing the overall TMC yield. The mechanism exploration reveals that 1,3-PDO acts as both a reactant and an acid catalyst, initiating a nucleophilic substitution reaction on P2 to produce P1. Under optimized conditions, we achieved a total TMC yield of 88%, the highest reported to date.This study provides a novel green synthesis route for TMC that holds great promise for industrial application, given its safer conditions and competitive yields.