| 摘要 |
Insoluble cation-exchange resins consist of sulphonated hydrolyzed cross-linked copolymers containing 3 to 15 per cent., on a molar basis, of a polyvinyl aromatic hydrocarbon which contains a plurality of vinylidene groups, an ester, preferably a lower alkanol ester, of acrylic or methacrylic acid, and optionally styrene, vinyl toluene or ethyl styrene as a third copolymerized constituent. Polyvinyl aromatic hydrocarbons specified are divinyl and trivinyl benzenes and naphthalenes, and polyvinyl anthracenes. Esters specified are methyl, ethyl, propyl, butyl and aliphatic polyhydric alcohol acrylates and methacrylates. Sulphonation, which may be carried out before or after hydrolysis, is preferably effected by swelling the copolymer with a liquid such as acetone, toluene, ethylene dichloride, trichloroethylene, and perchloroethylene, and then sulphonating with concentrated or fuming sulphuric acid, or chlorsulphonic acid. Hydrolysis may be effected by water if the copolymer has already been sulphonated, but may also be effected with aqueous hydrochloric or sulphuric acid, or aqueous sodium or potassium hydroxide. The copolymers may be prepared in bulk, solution, or, preferably, aqueous emulsion with the aid of a mixture of gelatin and a dispersing agent to produce the copolymers in bead form. Copolymerization may be carried out with the aid of catalysts such as ozone, ozonides, benzoyl, acetyl, lauroyl, stearoyl, di-tert.-butyl and hydrogen peroxides, tert.-butyl hydroperoxide, and the salts of perboric, persulphuric, and perchloric acids. |
