Transesterification for electronic-grade propylene glycol methyl ether acetate: Catalysis, deactivation & purification

Base-catalyzed transesterification was studied for PGMEA synthesis avoiding acid and water. • EtONa was identified as the catalyst and its deactivation mechanism was EA Claisen condensation. • In situ formation of sodium PGME can partially suppress catalyst deactivation at low loadings. • 99.90% PGMEA with negligible metal and moisture was achieved by customized rectification. • Process simulation of two-stage distillation shows that electronic-grade PGMEA is achievable. Propylene glycol methyl ether acetate (PGMEA) is an essential electronic-grade solvent in semiconductor manufacturing. However, the conventional esterification route introduces acid and water, requiring extensive purification to meet ultra-stringent quality standards. Herein, an alternative transesterification process with base catalysts that inherently avoids acid and water formation was systematically investigated. Sodium ethoxide (EtONa) exhibited the highest catalytic activity among the bases examined. Catalyst deactivation was traced to EtONa-catalyzed Claisen condensation of ethyl acetate (EA), while the formation of sodium PGME (PGMENa) partially suppressed this effect at low catalyst loadings. Using a customized rectification process, PGMEA with 99.90% purity and negligible metal content was obtained, and process simulation results indicate that electronic-grade purity (99.9999%) is achievable. This work demonstrates a practical and industrially viable route for the production of ultra-high-purity PGMEA.