Environmentally benign methanolysis of polycarbonate to recover bisphenol A and dimethyl carbonate in ionic liquids.

An environmentally friendly strategy for methanolysis of polycarbonate (PC) to recover bisphenol A (BPA) and dimethyl carbonate (DMC) was developed in which PC could be methanolyzed in an ionic liquid without any acid or base catalyst under moderate conditions. The effects of ionic liquid kinds, temperature, time, and methanol dosage on methanolysis results of PC were examined. It was showed that the methanolysis conversion of PC was almost 100% and the yields of both BPA and DMC were over 95% in presence of ionic liquid 1-n-butyl-3-methylimidazolium chloride ([Bmim][Cl]) and under the conditions of m(PC):m(CH(3)OH):m([Bmim][Cl])=2:3:2, reaction temperature 105 degrees C and time 2.5h. After easily separated from the product, the ionic liquid could be reused 8 times without obvious decrease in the conversion of PC and yields of BPA and DMC.