Esters of carbamic acid are usually prepared either by treating an alcohol with phosgene and adding ammonia to the chloroformic ester thus formed, or by treating the alcohal with cyanic acid. The reaction of urea with an alcohol has also been utilized'but the method has not been applied widely, probably because the lower alcohols, eg, methyl aad ethyl, require pressure. Butanol, however, reacts with urea at atmospheric pressure2 to give butyl ...
