METHOD FOR THE SEPARATION OF AN ISOCYANATE PRODUCED BY PHOSGENATION OF A PRIMARY AMINE IN THE GAS PHASE FROM THE GASEOUS RAW PRODUCT OF THE PHOSGENATION

摘要

The present invention relates to a process for separating an isocyanate prepared by reaction of a primary amine with an excess of phosgene in the gas phase from the gaseous crude product obtained in the reaction, wherein (i) the gaseous crude product is partially liquefied by contacting with a quenching liquid, (ii) the gas phase obtained in step (i) is partially condensed, (iii) the condensate obtained in step (ii) is used as the quenching liquid in step (i), (iv) the portions of the gas phase that were not condensed in step (ii) are at least partially liquefied, (v) the liquid phase obtained in step (iv) is likewise used as the quenching liquid in step (i), and (vi) the liquid phase obtained in step (i) is worked up to the pure isocyanate without previously being used as quenching liquid.