Catalytic synthesis of N-alkyl carbamates by methoxycarbonylation of alkylamines with dimethyl carbonate using Pb(NO3)2

Lead compounds such as Pb(NO3)(2) are efficient catalysts for the methoxycarbonylation of aliphatic amines (R-NH2: R = C3H7, C4H9, and C6H13) with dimethyl carbonate. Butylamine and hexylamine were almost quantitatively converted into methyl N-butyl carbamate and methyl N-hexyl carbamate, respectively, at 393 Kin 2 h, while 98% of propylamine was converted into methyl N-propyl carbamate with a 93% yield at 373 K in 2 It. By reduction of reaction temperature, butylamine was converted into methyl N-butyl carbamate with a 99% yield and a 98% selectivity at 313 K in 18 h. The effects of reaction variables were examined in the reaction of hexylamine with dimethyl carbonate. (C) 2002 Elsevier Science B.V. All rights reserved.