JPH0245617B

1. Process for the preparation of N-substituted urethanes of the general formula R**1 (NH-CO-OR**2 )n in which R**1 represents a saturated, unsubstituted, aliphatic hydrocarbon radical with 4 to 18 carbon atoms, a saturated cycloaliphatic hydrocarbon radical which has a total of 6 to 25 carbon atoms and is optionally alkyl-substituted and/or contains methylene bridges, or an aromatic hydrocarbon radical which has a total of 6 to 25 carbon atoms and is optionally alkyl-substituted and/or halogen-substituted and/or contains methylene bridges, R**2 denotes an aliphatic hydrocarbon radical which has a total of 6 to 18 carbon atoms and optionally contains inert substituents and/or ether groups, a cycloaliphatic hydrocarbon radical which has a total of 6 to 15 carbon atoms and optionally contains inert substituents, or an araliphatic hydrocarbon radical which has a total of 7 to 18 carbon atoms and optionally contains inert substituents, and n represents 1, 2 or 3, characterised in that a) primary amines of the general formula RX**1 (NH2 )n in which R**1 and n have the stated meaning, are reacted with b) ureas of the general formula R**3 -NH-CO-NH-R**3 in which R**3 denotes an aromatic hydrocarbon radical which has a total of 6 to 14 carbon atoms, optionally contains inert substituents and constitutes the basis of a primary aromatic monoamine which optionally contains inert substituents and has a boiling point at normal pressure at least 10 degrees C below the boiling point of the amine R**1 (NH2 )n , and c) primary or secondary alcohols which have at normal pressure a boiling point at least 5 degrees C higher than the amine R**3 -NH2 and which correspond to the general formula R**2 -OH in which R**2 has the stated meaning, at temperatures between 150 and 300 degrees C and the amine R**3 -NH2 formed, optionally in admixture with alcohol R**2 -OH, is removed, by distillation, from the reaction mixture during the reaction.