Patent ID: 7589227
Filing Date: 2009-09-15
Classification: C07C

Abstract:
1. A method for the manufacture of organic carbonates, comprising converting urea, a substituted urea, a salt or ester of carbamic acid or one of its N-substituted derivatives in a first stage with a polymeric alcohol of the general formula I in which R stands for a straight chain or branched chain alkylene group having 2 to 12 carbon atoms and n is a number between 2 and 20, or with a complete or partially hydrolyzed polyvinylalcohol of the general formula II in which R′ stands for an alkyl, aryl or acyl group having 1-12 carbon atoms, p and q are numbers between 1 and 20, or dissolved in mixtures of these compounds, without or in the presence of an ammonia splitting catalyst, which converting is to a carbonate and carbamate containing mixture, and a thereby liberated ammonia or amine is removed by means of a stripping gas and/or steam and/or vacuum, and in a second stage a mixture containing the carbonate and carbamate is reacted with an alcohol or a phenol with formation of their carbonates and back formation of the polymeric alcohol or polyvinylalcohol of formulas I or II.