Carbamates, exothermic synthesis

Scheme 61 An example of the reaction protocol employed for the exothermic synthesis of carbamates.

The first step is to react ammonia with carbon dioxide to form ammonium carbamate. The reaction is highly exothermic. The second step is the endothermic dehydration reaction of ammonium carbamate. The overall synthesis reaction is still highly exothermic. 

Carbamate synthesis Methyl carbamates 91% Control over exothermic conditions 2004/[54]... 

Synthesis o-f carbamates. The reaction o-f methanol with phenylisocyanate is exothermic [232] ... 

Reactions of ammonia and carbon dioxide forming ammonium carbamate constituted the first step, which is exothermic in nature. This is followed by the endothermic decomposition of ammonium carbamate, through dehydration, in the second step to form urea. Recently, Xiang et al. [280] reported urea synthesis at atmosphere pressure and ambient temperature. 

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