Patent ID: 9428627
Filing Date: 2016-08-30
CPC Classification: C07C,C08G,C08J,C08K,C08L,Y02W

Claim Text:
1. A method for recovering a dihydroxy aromatic compound and a dialkyl carbonate from a composition comprising a polycarbonate and a phosphorus-containing flame retardant, the method comprising heating the polycarbonate-containing composition in the presence of an alcohol and a transesterification catalyst, having non-neutralizable groups, selected from the group consisting of a tin compound, a zinc compound, a titanium compound, an aluminum compound, or a combination thereof, at a temperature of 70° C. to 200° C. and a pressure of 50 mbar to 40 bar for a time sufficient to depolymerize the polycarbonate to provide a dihydroxy aromatic compound and a dialkyl carbonate; wherein the catalyst is present in an amount from 0.01 wt. % to 1 wt. % based upon the total weight of the polycarbonate-containing composition and the alcohol.