| 摘要 |
Cation exchange resins are made by introducing sulphonic acid groups into the benzene rings of a resin formed by reacting epichlorhydrin, a dihydric phenol and a phenol containing three or more hydroxy groups as a cross-linking agent. Specified dihydric phenols include resorcinol, catechol, hydroquinone and dihydric phenols derived from acetone or formaldehyde and phenols, e.g. diphenylol propane. The cross-linking agents specified are phloroglucinol, pyrocatechol and tetrahydric phenols derived from acetone and catechol, hydroquinone or resorcinol, e.g. bis-(2,4-dihydroxy phenyl)-dimethyl methane, whilst additional cross-linking agents, e.g. polyamines such as diethylene triamine, bifunctional compounds such as glyoxal, succinic acid, dichloromethyl ether, hexamethylene di-isocyanate and water soluble resins of the urea-, melamine- and phenol-formaldehyde types may be included. Sulphonic acid groups can be introduced into the cross-linked resin by sulphuric acid or oleum. In the example, a tetrahydric phenol prepared from resorcinol and acetone is mixed with diphenylol propane and epichlorhydrin and heated in caustic soda solution to solidification. The solid is dried, broken up and sulphonated with sulphuric acid. |
