Process for the preparation of esters of carbonic acid

Abstract

A process is described whereby carbonic acid esters, i.e., alkyl, aryl and cycloalkyl carbonates, are prepared by reacting an alcohol with oxygen and carbon monoxide in the presence of a catalyst selected from copper complexed with an organic molecule.

What we claim is: 
     
       1. A process for the preparation of esters of carbonic acid having the general formula: ##STR2## wherein R is a hydrocarbon radical selected from the class consisting of alkyl, aryl or cycloalkyl radicals characterized in that an alcohol represented by the formula ROH in which R has the aforesaid meaning is reacted with carbon monoxide and oxygen in the presence of a catalyst consisting of cuprous chloride complexed with an organic ligand selected from the group consisting of pyridine, dipyridyl, imidazole, phenanthroline alkyl or aryl, phosphines, dimethylsulfoxide, dimethylformamide, quinuclidine, CH 3  CN, C 6  H 5  CN, malonitrile, succinodinitrile and adiponitrile. 
     
     
       2. A process according to claim 1 characterized in that the reaction is carried out in a solvent adapted to produce azeotropic mixtures with water and selected from: a. the same alcohol as that from which the ester is prepared;   b. an organic compound adapted to be complexed by the employed catalyst;   c. an inert solvent; or a mixture of the said solvents.   
     
     
       3. A process according to claim 2 characterized in that the solvent is the reactant alcohol and the catalyst is put in as a complex. 
     
     
       4. A process according to claim 1 characterized in that the temperature is preferably selected in the range from -20° C. to +110° C. 
     
     
       5. A process according to claim 4 characterized in that the pressure is sufficient to ensure that the employed solvent will be kept in the liquid state at the process temperature. .Iadd. 
     
     
       6.  A process for the preparation of esters of carbonic acid having the general formula: ##STR3## wherein R is a hydrocarbon radical selected from the class consisting of alkyl, aryl or cycloalkyl radicals characterized in that an alcohol represented by the formula ROH in which R has the aforesaid meaning is reacted with carbon monoxide and oxygen in the presence of a catalyst consisting of cuprous chloride complexed with an organic ligand selected from the group consisting of pyridine, dipyridyl, imidazole, phenanthroline alkyl or aryl, phosphines, dimethylsulfoxide, dimethylformamide, quinuclidine, CO, CH 3  CN, C 6  H 5  CH, malonitrile, succinodinitrile and adiponitrile..Iaddend.