Boosting the methanolysis of polycarbonate by the synergy between ultrasound irradiation and task specific ionic liquids

Abstract

In an attempt to perform polycarbonate chemical recycling in a more sustainable way, we took into consideration the combined use of ultrasound irradiation and task specific ionic liquids. Towards this aim, the methanolysis of polycarbonate, into dimethylcarbonate and bisphenol A, was carried out in the presence of cholinium-based ionic liquids featuring anions derived from amino acids and other eco-friendly species. The target process was optimized in terms of both energy and material amounts as well as in terms of the nature of the catalysts used. The proposed protocol allowed high conversion and yields of bisphenol A to be obtained, under milder conditions compared to the ones so far reported in the literature, perfectly fulfilling green chemistry principles. The best performing catalyst can be reused without significant loss in performance and the methodology can be successfully applied to post-consumer polycarbonate samples.