Patent GB-1378007-A (GB)
Title: Ion-exchange resin and ion-separation method using the same
IPC: B01J43/00
Filed: 1971-12-29
Abstract: 1378007 Ion exchangers having surface shield groups TOKUYAMA SODA KK 29 Dec 1971 [29 Dec 1970] 60528/71 Heading C3P  An ion-exchange resin comprises a threedimensional solvent insoluble organic high molecular weight granular polymer having a core and a substantial surface contiguous with the core, the core having ion exchange groups chemically attached thereto by covalent or co-ordination bonds uniformly throughout, the said substantial surface possessing shield groups chemically attached thereto by covalent or co-ordination bonds, the shield groups having or being capable of having a charge opposite to that of the said ion exchange groups, the core being substantially free of the shield groups. The degree of dissociation of the shield groups in water is preferably at least 0À001, and they are preferably of high molecular weight. The substantial surface is defined as being the surface of each granule and the region immediately below the surface of each granule. Methods for forming the resin are: (i) an acid cation exchanger containing an -SO 2 Cl, -CO 2 Cl, phosphonic acid halide group or carboxylic acid anhydride group has its surface reacted with a compound having at least one primary or secondary amino group to produce shield groups attached via an acid amide linkage. Remaining acid halide groups are converted to acid groups; (ii) the surface of the resin granules is chloromethylated and then aminated with a compound having at least two primary, secondary or tertiary amino groups, and then a cation exchange group (e.g. -SO 3 H) is introduced into the core of the resin; (iii) the resin is chloromethylated throughout and then reacted at the surface with a compound containing an amino group and an acid group (e.g. an aminocarboxylic acid or amino phenol). Thereafter the remaining chloromethyl groups in the core are aminated to produce an anion exchanger; (iv) a weakly basic anion exchanger containing primary, secondary or tertiary amino groups is reacted at the surface with a compound containing acid groups (e.g. a polymer such as polystyrene sulphonic acid) so that some of said acid groups become attached via an acid amide linkage. The rest of the unreacted acid groups form the oppositely charged shield groups; (v) a resin as in (iv) is reacted with an acid compound such as phenol sulphonic acid by using an aldehyde to form a linkage between the amino group and the phenol group, leaving the acid group free (the shield group). In the examples: (1) a styrene/divinylbenzene copolymer (st/dvb) is chlorosulphonated throughout and reacted with polyethylene imine at the surface and the ClSO 3 - groups in the core are converted to sodium sulphonate groups; (3) st/dvb is chloromethylated throughout and the surface reacted with Na-1-amino-8-naphthol-3,6-disulphonate to produce acid shield groups (amino reacted with -CH 2 Cl); the core is then aminated with trimethylamine; (4) st/dvb is chloromethylated and then reacted with monomethyl amine throughout; the surface is then reacted with polystyrene chlorosulphonate to give acid shield groups attached via acid amide links; (5) st/dvb is chloromethylated throughout and the surface reacted with polyvinylpyrrolidone and the core with chlorosulphonic acid; the surface groups are quaternized and the core groups converted to sodium sulphonate groups; (6) st/dvb is surface chlorosulphonated to produce (ultimately) sodium sulphonate groups and the remainder is then chloromethylated and reacted with trimethylamine; (7) the surface of a conventional cation exchanger ("Amberlite", Trade Mark) is reacted with 2-methyl-5-vinyl pyridine under irradiation, and quaternized; and (8) the surface of poly-2- methyl-5-vinyl pyridine is reacted with chloromethylated polystyrene to introduce polystyrene groups via -CH 2 - links; the surface polystyrene groups are then chlorosulphonated and the pyridine groups quaternized throughout.