Abstract: Organic mono- or di-isocyanates are prepared by the decomposition of the corresponding urethanes, by means of a continuous process in which:(a) an urethane flow is continuously fed to a decomposition reactor containing a liquid mixture, composed of a high boiling inert organic solvent, of an unaltered urethane and isocyanate, kept at the boiling conditions of the solvent, at a temperature suitable to decompose the urethane and evaporate the alcohol which is the co-product of the reaction;(b) the liquid mixture is continuously withdrawn from the reactor in (a) and is fed to a flash equipment, at an operating temperature lower than the decomposition temperature of the urethane, where the isocyanate is partially evaporated and the residuous liquid mixture is recycled to the reactor in (a); and(c) the steam flow generated in (b) is distilled to separate the isocyanate in pure or substantially pure form.

Abstract: A process for preparing carbamates is disclosed, in which:a stoichiometric or higher-than-stoichiometric amount of an alkyl carbonate or a cycloalkyl carbonate is reacted with an aliphatic, cycloaliphatic or aromatic amine, in a first reaction step, by operating in the presence of a carbamation catalyst, in order to produce a mixture of a carbamate and an urea,the urea contained in the reaction product from the first process step is reacted with carbonate, in a second reaction step, in order to produce the corresponding carbamate, andthe reaction mixture coming from the second process step is submitted to treatments in order to recover the carbamate.The process makes it possible high yields and high values of selectivity to the useful reaction product to be obtained.