PROCESS FOR THE PRODUCTION OF ION EXCHANGERS WITH TERTIARY AMINO GROUPS

1,222,929. Ion exchange resins. CHEMIEKOMBINAT BITTERFIELD VEB. 25 Sept., 1969, No. 47258/69. Heading C3P. Weakly basic anion exchangers with tertiary amino groups are prepared by a process wherein an ion exchanger containing primary and/or secondary amino groups is pre-swollen in dilute formic acid and then treated with concentrated formic acid and with an aldehyde or ketone at an initial temperature of at least 0‹ C., the temperature being increased stepwise during the course of the reaction to reflux temperature. The resin may be prepared by copolymerizing styrene or methylstyrene with divinyl benzene, chloromethylating and aminating, or by copolymerizing an acrylic acid derivative with divinyl benzene and aminating. Specified aldehydes and ketones are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and acetophenone, which may be used in aqueous or alcoholic solutions. Many suitable amines are listed and examples describe the reaction of formic acid and formaldehyde with preswollen exchangers derived from chloromethylated (1) styrene/divinylbenzene copolymer; and (2) styrene/acrylonitrile/divinylbenzene copolymer and ethylene diamine; chloromethylated (3) styrene/divinylbenzene copolymer and diethylene triamine; (4) ethyl acrylate/divinylbenzene copolymer and diethylenetriamine; and (5) methyl acrylate/divinyl benzene copolymer and triethylene tetramine.