PROCESS FOR THE PRODUCTION OF N-AND O-SUBSTITUTED MONO-OR BIS-URETHANES AND THE USE THEREOF AS STARTING MATERIAL FOR THE PRODUCTION OF ALIPHATIC ISOCYANATES

摘要

1. A process for the production of N- and O-substituted mono- or bis-urethanes, characterized in that urethanes corresponding to the following formula R**1 -(NH-CO-O-R**2 )n in which R**1 represents an n-functional, aliphatic C1 -C6 -hydrocarbon radical optionally containing ether bridges or an n-functional cycloaliphatic C6 -C13 -hydrocarbon radical, R**2 represents a hydroxyalkyl group containing from 2 to 3 carbon atoms, 2 carbon atoms being present between the oxygen atom of the hydroxyl group and the oxygen atom of the urethane group, and n = 1 or 2, are subjected to a transesterification reaction with alcohols containing only primary hydroxyl groups and corresponding to the following formula R**3 -(OH)m in which R**3 represents a monofunctional (m = 1), linear or branched, saturated aliphatic C8 -C18 -hydrocarbon radical optionally containing ether bridges, a monofunctional (m = 1) araliphatic C8 -C15 -hydrocarbon radical or a difunctional (m = 2), linear or branched, saturated aliphatic C3 -C18 -hydrocarbon radical optionally containing ether bridges in which at least 3 carbon atoms are present between the two hydroxyl groups, and m = 1 or 2 with the proviso that m and n cannot both have the value 2, in the presence of catalysts selected from the group comprising (i) oxides, hydroxides, salts of organic acids, salts of weak organic acids and organic complex compounds of monovalent thallium, and (ii) organic acid salts of 2- and 4-valent tin and organic compounds of 4-valent tin containing organic radicals which are not bound like salts, with elimination of alcohols corresponding to the following formula R**2 -OH.