Patent GB-737924-A (GB)
Title: Improvements in or relating to polymeric compounds with anion-exchange properties
IPC: B01J41/12
Filed: 1952-07-21
Abstract: A strongly basic anion exchange material consists of an insoluble, infusible macromolecular organic resin containing a plurality of tertiary sulphonium groups each of which includes at least two alkoxyaryl groups attached to sulphur.  The resins may be prepared by reacting a tertiary sulphonium salt containing at least two alkoxyaryl groups, or a mixture of a tertiary sulphonium salt containing one alkoxyaryl group and an alkoxyaryl compound, with formaldehyde in presence of acid, or by reacting a dialkoxyaryl sulphide with formaldehyde in presence of acid and heating the product with a dialkyl sulphate or by condensing a dialkoxyaryl sulphoxide with formaldehyde in presence of acid and treating the product with concentrated sulphuric acid and an alkoxyaryl compound. The products are particularly valuable for removing silicic acid ions from solutions, being regenerated with alkali.  They may be comminuted, granulated, or flaked or prepared as beads by dispersing the reacting substances in an inert liquid. Alternatively the reaction mixture may be shaped by extrusion or spraying before it is completely gelled.  Films, sheets or plates of the resins may be suitably reinforced.  They are particularly valuable for electrolysis or electrodialysis being practically impermeable to cations.  In the examples: (1) trianisyl sulphonium chloride and sulphuric acid at 0 DEG  C. were mixed with paraformaldehyde and sulphuric acid also at 0 DEG  C. with stirring. Cooling kept the reaction temperature below 80 DEG  C.  The gel was allowed to stand to harden, then broken up, screened and washed with soda lye to remove sulphate ions.  The hardness of the product may be influenced by addition to the reaction mixture of trifunctional ingredients such as anisol, phenetol or diphenyl ether; (2) triphenetyl sulphonium chloride was similarly condensed with formaldehyde.  In example (3) trianisyl sulphonium chloride was condensed with formaldehyde in suspension in carbon tetrachloride yielding a granular product; (4) dianisyl methyl sulphonium sulphate was condensed with formaldehyde; (5) dianisyl sulphoxide was condensed with formaldehyde and the flaked product was reacted with anisol in presence of sulphuric acid; (6) a mixture of dimethyl anisyl sulphonium sulphate with anisol or with trianisyl sulphonium chloride was reacted with formaldehyde; (7) dianisyl sulphide was condensed with formaldehyde and the product reacted with dimethyl sulphate; (8) trianisyl sulphonium chloride is mixed with sulphuric acid and paraformaldehyde and the solution of reactants formed into a foil on a heated drum.  The foil is soaked loose from the drum and freed from acid by rinsing.ALSO:Trianisyl sulphonium chloride is prepared by reacting anisol with thionyl chloride in presence of AlCl3.  Triphenetyl sulphonium chloride is prepared by reacting diphenetyl sulphonide with phenetol in presence of AlCl3. Dianisyl sulphide (B. Pt. 196 DEG  C. at 1 mm. pressure) is prepared by reacting sulphur dichloride with anisol at 40-70 DEG  C. and distilling in vacuo.  It was heated at 80 DEG  C. with dimethyl sulphate to yield a solution of dianisyl methyl sulphonium sulphate in sulphuric acid.  Dimethyl anisyl sulphonium sulphate was prepared by mixing anisol and dimethyl sulphoxide in conc.-sulphuric acid with cooling and stirring.ALSO:Synthetic resins containing a plurality of tertiary sulphonium groups each with at least two alkoxyaryl groups attached to the sulphur atom (see Group IV (a)) are strongly basic anion exchange materials particularly useful for removal of silicic acid ions from solutions containing them.  Regeneration is effected with alkali.  The resins may be formed as flakes, beads, films, sheets or plates.  Mechanical reinforcement may be provided, e.g. in the form of threads of synthetic resin.  Tests are described on specific resins to indicate their strong basicity and power of retaining silicic acid ions without leakage up to the point of "break through."