Patent ID: 9181392
Filing Date: 2015-11-10
Classification: C08G

Abstract:
1. A method for producing a polycarbonate polyol, the method comprising: charging a vessel with butanediol (BDO); charging the vessel with a polymerization catalyst; and adding to the vessel dimethyl carbonate (DMC) at a rate of at least 2.4 g of DMC per minute per kg of BDO to produce polycarbonate polyol at a polycarbonate polyol yield of at least 80% of a theoretical yield, wherein: at least the BDO is heated to between about 120 degrees Celsius and 240 degrees Celsius before the DMC is added to the vessel, and a transesterification polymerization reaction is performed by reacting the BDO and the DMC at a temperature between about 120 degrees Celsius and 240 degrees Celsius to form the polycarbonate polyol having a number average molecular weight of between about 1500 and 2500 g/mol.