申请人:BOCK Michael
公开号:US20120142960A1
公开(公告)日:2012-06-07
The invention relates to a method for purifying mixtures comprising 4,4′-methylenediphenyl diisocyanate, which comprises purifying by distillation a mixture I comprising 4,4′-methylenediphenyl diisocyanate having a hydrolyzable chlorine content as specified in ASTM D4663-10 of greater than 100 ppm by means of a column K
1
, wherein the gaseous stream comprising the mixture I is brought into contact in the column K
1
with at least one liquid compound A which has the same or higher boiling point than 4,4′-methylenediphenyl diisocyanate and which has a hydrolyzable chlorine content as specified in ASTM D4663-10 of a maximum of 100 ppm, and wherein the gaseous stream O obtained at the top of the column comprises 4,4′-methylenediphenyl diisocyanate has a hydrolyzable chlorine content as specified in ASTM D4663-10 of a maximum of 100 ppm.