[EN] PROCESS FOR PREPARING CARBAMATES<br/>[FR] PROCEDE DE PREPARATION DE CARBAMATES
申请人:COUNCIL SCIENT IND RES
公开号:WO2005063698A1
公开(公告)日:2005-07-14
A process for the preparation of carbamates from organic urea and organic carbonate in presence of a solid base catalyst is disclosed. The process works at the milder reaction conditions and utilizes inexpensive catalysts that can be recycled several times.
A process for the preparation of carbamates from organic urea and organic carbonate in presence of a solid base catalyst is disclosed. The process works at the milder reaction conditions and utilizes inexpensive catalysts that can be recycled several times.
The role of alcohol in the catalytic reductive carbonylation of nitrobenzenes to carbamates in the presence of Rh(CO)4− or Ru3(CO)12
作者:Charng-Hing Liu、Chien-Hong Cheng
DOI:10.1016/0022-328x(91)86451-u
日期:1991.11
The selectivity of N-phenylcarbamate from the reductive carbonylation of nitrobenzene using Rh(CO)4- or Ru3(CO)12-Et4N+ Cl- as the catalyst is much higher in t-butyl alcohol than in primary or secondary alcohols; the latter two alcohols are readily involved in the reduction of nitrobenzene to aniline leading to lower selectivity of the corresponding carbamates. For example, when 2-butanol was used as the solvent for the reductive carbonylation of nitrobenzene, 2-butanone and aniline were observed in a molar ratio of 1:1. Similarly, the reductive carbonylation of p-nitrotoluene to give the corresponding carbamate in t-butyl alcohol is also higher in yield than in 2-butanol or in butanol. However, for dinitroarenes the selectivity of carbamates is low using either (t)BuOH or other primary and secondary alcohols.
Pizzotti, Maddalena; Cenini, Sergio; Quici, Silvio, Journal of the Chemical Society. Perkin transactions II, 1994, # 4, p. 913 - 918