Patent ID: 7329776
Filing Date: 2008-02-12
Classification: C07C

Abstract:
1. A process for the continuous preparation of a cycloaliphatic diisocyanate, comprising: reacting one or more cycloaliphatic diamines with one or more carbonic acid derivatives and one or more alcohols to form a reaction mixture comprising one or more cycloaliphatic diurethanes, subsequently separating the cycloaliphatic diurethanes from low and medium boilers present in the reaction mixture and thermally cleaving the diurethanes to form one or more cycloaliphatic diisocyanates, while continuously discharging a portion of a cleavage residue formed by the separating, removing high boiler components from the discharged cleavage residue, reurethanizing the purified discharge with alcohol, and recycling the reurethanized discharge into the process.