LOW TEMPERATURE BRINE SEPARATION OF WATER AND ISOCYANATE

摘要

Isocyanates produced by vapor-phase catalytic oxidative dehydrogenation of corresponding N-substituted formamides are readily separated from by-product water by contacting the reaction mixture, in the vapor phase, with a cold brine mixture comprising water and about 25% to about 35% by weight of a salt or salts selected from the group consisting of NaCl, CaCl2, and MgCl2, the brine mixture having been maintained at a temperature between about 0 DEG C. and its freezing point prior to contact with the reaction mixture containing isocyanates.