One Pot Synthesis of Methyl N-Phenyl Carbamate from Aniline, Urea and Methanol

Abstract

Methyl N-phenyl carbamate (MPC) was synthesized from aniline, urea and methanol. The effects of catalysts, loading amounts, preparation condition of catalyst and reaction condition on the synthesis of MPC were investigated. It was shown that KNO 3 modified zeolite HY gave the best performance to MPC formation among the evaluated catalysts, over which 93.1% aniline conversion and 82.6% MPC selectivity were obtained under the optimum reaction condition. Additionally, a possible catalytic mechanism to the formation of MPC in this reaction was proposed.

Methyl N-phenyl carbamate synthesis over Zn/Al/Ce mixed oxide derived from hydrotalcite-like precursors

“…MPC could be synthesized via the reactions of phenylurea and dimethyl carbonate (DMC) 4 and/or methanol, 5 aniline and DMC 2,6-10 and/or methyl carbamate (MC), 3,11 and even aniline and C 1 source (e.g. CH 3 OH and CO 2 ), [12][13][14] etc. And some new synthetic paths have also been developed recently.…”

One-Pot Synthesis of Dialkyl Hexane-1,6-Dicarbamate from 1,6-Hexanediamine, Urea, and Alcohol over Zinc-Incorporated Berlinite (ZnAlPO4) Catalyst

“…The selectivity for 2 exhibited an inverse trend with Zn/AlPO 4 molar ratio, compared with that for 3 and 4, and achieved a maximum value at Zn/AlPO 4 = 0.04:1. The selectivity for butyl 6-aminohexyl-1-carbamate (1) first slightly increased and then decreased with Zn/AlPO 4 molar ratio from 0:1 to 0.04:1, with subsequent increase when Zn/AlPO 4 > 0.04:1 (entries [8][9][10][11]. In addition, the results show that AlPO 4 had no catalytic activity for the synthesis of dialkyl carbamates from diamines, urea, and alcohols (entries 1,2).…”

“…The reactor was a stainless steel V T = 500 mL autoclave with electric heating and dynamoelectric stirring. This apparatus was equipped with a back-pressure regulator (6), a sampling valve (13), a condenser (5), and a temperature and stirring speed controller (9). A filter was fixed at the end of the sample tube in the reactor, to prevent the heterogeneous catalyst from leaving the reactor during on-line sampling.…”

“…However, a number of drawbacks may occur in the route, including difficult handling of the toxic phosgene and the seriously corrosive side product HCl [2]. Several phosgene-free routes for organic carbamates synthesis have also been reported [4][5][6][7][8][9], among which the synthesis from amines, urea and alcohols by a one-pot reaction [9] has received considerable attention. This route appears to be promising because, on the one hand, ammonia is obtained as a main byproduct and, on the other hand, urea can be prepared on a large scale by the dehydration of ammonia and CO 2 [10].…”

“…It is interesting that the main byproducts mixture (1, 3-5) mentioned above can also be directly employed as the raw materials in the synthesis of the desired product 2 by Reactions (5), (6), (8) and (9) [15,16,19,20,26,28].…”