MULTIPLE-STEP PROCESS FOR THE PREPARATION OF 3- ISOCYANATOMETHYL-3,5,5-TRIMETHYLCYCLOHEXYLISOCYANATE

摘要

MULTIPLE-STEP PROCESS FOR THE PREPARATION OF 3-ISOCYANATOMETHYL-3,5/5-TRIMETHYLCYCLOHEXYLISOCYANATE This invention discloses a non-phosgene process for the preparation of 3-isocyanatomethyl-3,5,5-trimethyl-cyclohexylisocyanate by the reaction of the precursor diamine with urea and an aliphatic alcohol in the presence of a dialkyl carbonate and an alkyl carbonate. The intermediate diurethane is separated from starting materials and by-products and thermally cleaved to alcohol and diisocyanate which are separated by fractional condensation of the products from the vapor state. This process gives high yields of the desired diisocyanate and lends itself particularly to continuous processing.