Carbamates were prepared by one-pot synthesis from carbon dioxide, amine and alkyl chloride with N,N,N,N-tetramethyl guanidine (TMG) as catalyst, acetonitrile (ACT) as solvents at a pressure of 0.10 MPa and temperature of 70～80 ℃. Effects of the converting ratio and yield were investigated. The results showed that the optimum technological conditions should be that n(amine)∶n(alkyl chloride)＝3～4, the reaction temperature was 70～80 ℃, and reaction time was 2～3 h. The purity of the refined of carbamates was 99.9%, and the yield of carbamates was in the range of 68.7%～81.3%.

Key words: steric effect, carbon dioxide, nucleophile substitution, carbamate