| 摘要 |
Cation exchange resins are obtained from insoluble cross-linked copolymers of monovinyl and divinyl aromatic compounds by reacting with phosphorus thiochloride and hydrolysing the thiophosphonyl dichloride groups so formed to thiophosphonate groups, i.e. the group -PS(OH)2 and salts thereof, e.g. the sodium, potassium, calcium, magnesium or ammonium salts. The copolymer is derived from 80 to 99.5 per cent of one or more monovinyl aromatic hydrocarbons, e.g. styrene, vinyltoluene, vinylxylene, ethylvinylbenzene or isopropylvinylbenzene, and from 20 to 0.5 per cent of a divinyl aromatic hydrocarbon, e.g. divinyl benzene, toluene, xylene or ethylbenzene by bulk, emulsion or suspension polymerization in the presence of a catalyst such as benzoyl peroxide, lauroyl peroxide, di-tertiarybutyl peroxide, ditertiarybutyl di-perphthalate or cumene hydroperoxide. Suspension polymerization in water or brine yielding small beads is preferred. The reaction with phosphorus thiochloride is carried out in the presence of a Friedel-Crafts catalyst, e.g. aluminium chloride, ferric chloride, stannic chloride or zinc chloride, at from 25 DEG to 125 DEG C. until the copolymer contains an average of at least one thiophosphonyl dichloride group per ten aromatic nuclei and these groups are then hydrolysed by heating with water, or aqueous acid or alkali. In the example a terpolymer of styrene, ethylvinylbenzene and divinylbenzene is phosphonated.
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