Carbamates are raw materials for the manufacture of polyurethane and usually produced by phosgene process. But, this process has two shortcomings. One is toxicity of phosgene and the other is the production of highly corrosive hydrochloric acid. Alter...
Carbamates are raw materials for the manufacture of polyurethane and usually produced by phosgene process. But, this process has two shortcomings. One is toxicity of phosgene and the other is the production of highly corrosive hydrochloric acid. Alternatively direct synthesis from CO2 is nontoxic and environment-friendly process. CO2 is converted to carbamate by reacting with amine and alcohol catalyzed by dialkyltin compound. Dibutyltin oxide(DBTO) was found to be an effective catalyst which gives a moderate to good yield. The addition of acetonitrile as a dehydrating agent under high pressure CO2 can further promote the reaction.