| 摘要 |
The invention relates to a process for purifying mixtures comprising 4,4'-methylene diphenyl diisocyanate, comprising the distillative purification of a mixture I comprising 4,4'-methylene diphenyl diisocyanate having a content of hydrolysable chlorine to ASTM D4663-10 of more than 100 ppm by means of a column K1, wherein the gaseous stream consisting of mixture I is contacted in column K1 with at least one liquid compound A which has a boiling point which is the same as or higher than 4,4'-methylene diphenyl diisocyanate and which has a content of hydrolysable chlorine to ASTM D4663-10 of at most 100 ppm, and wherein the gaseous stream O which is obtained at the top of the column and comprises 4,4'-methylene diphenyl diisocyanate has a content of hydrolysable chlorine to ASTM D4663-10 of at most 100 ppm. |
