GB622935A - A process for the production of insoluble macro-molecular azo compounds - Google Patents

Abstract

Macro-molecular azo-compounds insoluble in water, dilute acids and dilute bases are prepared by coupling components, one of which is derived from polystyrene, the degree of polymerization of which is not less than 1000. The other component may be monomeric, e.g. diazotized aniline, or polymeric, e.g. ligno sulphonic acid from sulphite waste liquor. The azo-compounds may be halogenated, nitrated or sulphonated. Polystyrene is nitrated by dissolving it in 90 per cent nitric acid while stirring and cooling. The temperature is maintained below 10 DEG C. for 17 hours and the solution poured into cold water. The polymeric nitrostyrene is treated in an autoclave with aqueous sodium disulphide, whereby 50 per cent of the nitro-groups are reduced to amino groups. The polymeric aminostyrene is diazotized by adding water and concentrated hydrochloric acid with agitation and cooling to 10 DEG C. and sodium nitrite added dropwise. Examples describe coupling polystyrene diazonium chloride with (1) salicylic acid; (3) p-phenol-sulphonic acid; (4) 2-hydroxy-naphthalene-sulphonic acid-3,6; (5) m-phenylamine-diamine. In example (2) the product of (1) is nitrated with a mixture of concentrated sulphuric and nitric acids at - 10 DEG C. In example (6), polystyrene diazonium chloride is heated with dilute sulphuric acid to form polyhydroxystyrene, which is coupled with diazotized aniline, which is (7) sulphonated with oleum. The products may be used as ion exchangers, as pigments or as pH indicators. Specification 545,529 is referred to.ALSO:Macro-molecular azo-compounds insoluble in water, dilute acids and dilute bases are prepared by coupling components, one of which is derived from polystyrene, the degree of polymerization of which is not less than 1000. The other component may be monomeric, e.g. diazotized aniline, or polymeric, e.g. ligno sulphonic acid from sulphite waste liquor. The azo compounds may be halogenated, nitrated or sulphonated. Polystyrene is nitrated by dissolving it in 90 per cent nitric acid while stirring and cooling. The temperature is maintained below 10 DEG C. for 17 hours and the solution poured into cold water. The polymeric nitrostyrene is treated in an autoclave with aqueous sodium disulphide, whereby 50 per cent of the nitro-groups are reduced to amino groups. The polymeric aminostyrene is diazotized by adding water and concentrated hydrochloric acid with agitation and cooling to 10 DEG C. and sodium nitrite added dropwise. Examples describe coupling polystyrene diazonium chloride with (1) salicylic acid; (3) p - phenol-sulphon acid; (4) 2 - hydroxy - naphthalene - sulphonic acid-3,6; (5) m-phenylene-diamine. In example (2) the product of (1) is nitrated with a mixture of concentrated sulphuric and nitric acids at -10 DEG C. In example (6) polystyrene diazonium chloride is heated with dilute sulphuric acid to form polyhydroxystyrene, which is coupled with diazotized aniline, which is (6) sulphonated with oleum. The products may be used as ion exchangers, as pigments or as pH indicators. Specification 545,529 is referred to.