| 摘要 |
In a process for sulphonating a benzene-swellable copolymer of one or more monovinyl aromatic compounds, e.g. styrene, o-, m- or p-chlorostyrene and dichlorostyrene, and 3 to 20 per cent of one or more polyvinyl aromatic compounds, e.g. divinyl and methyl- or ethyldivinyl benzene, the copolymer is first swelled by an organic liquid such as benzene, toluene, xylene, ethyl-, isopropyl-, or chlorobenzene, tetrachlorethane and tetrachloroethylene. The copolymers may be made by heating in bulk, or in solution in an inert solvent, e.g. benzene, toluene, ethyl benzene or acetone, which may also act as swelling agents. The copolymer may be swelled as a continuous mass, rods, sheets or as granules, which may be obtained directly by polymerization in an aqueous suspension containing protective colloids or thickenging agents, e.g. starch, gum tragacanth, methyl cellulose, or the sodium salt of carboxymethyl cellulose. An example describes the preparation of a granular terpolymer of divinyl benzene, ethyl-vinyl benzene and styrene using benzoyl peroxide as a catalyst. Sulphonation may be effected by concentrated or fuming sulphuric acid or chlorosulphonic acid and the product may be obtained as the free sulphonic acid, or by the addition of a concentrated aqueous solution of an inorganic salt, e.g. sodium chloride, as a salt, the concentration of ionizable solutes in the aqueous liquor in contact with the product being gradually decreased by dilution. The products may be used as cation-exchange resins. U.S.A. Specifications 2,089,444 and 2,366,007 are referred to. |
