GB1291908A - Process for the production of methylene bridged polyphenyl polyamines - Google Patents

Abstract

1291908 Methylene-bridged polyphenyl polyamines UPJOHN CO 8 Sept 1970 [20 Oct 1969] 42969/70 Heading C2C Methylene-bridged polyphenyl polyamines containing di-(aminophenyl) methane having a 4,4<SP>1</SP>-isomer content of at least 98% are prepared in a continuous process comprising intimately intermixing at a temperature of 0‹ to 60‹ C. rapidly flowing fluid streams of aqueous aniline and aniline hydrochloride and aqueous formaldehyde in a molar proportion of 4:1 to 1À5:1 at the entry port of a continuous tubular reactor; causing said intermixed fluid streams to flow through the reactor at below 75‹ C. at such; a rate that substantially no backmixing occurs continuously passing the reaction mixture from the exit part of the reactor to a cooling zone in which the reaction mixture is continuously recycled so as to maintain the temperature of the reaction mixture below 60‹ C. but above the temperature at which solid material separates from the mixture; continuously removing the reaction mixture from the cooling zone at a rate corresponding to that at which it is fed in and passing the reaction mixture to a final reaction zone in which its temperature is in the range 60‹ to 120‹ C.; and continuously removing from said final reaction zone a mixture of methylene bridged polyphenyl polyamines at a rate corresponding to that at which the intermediate reaction mixture is passed to the final reaction zone. There may be interposed between the cooling zone and final reaction zone a holding zone where the reaction mixture is maintained at 40‹ to 70‹ C. for an average residence time of 30 to 240 minutes. The polyamine mixture may be phosgenated to the corresponding polyisocyanates.