| 摘要 |
Resins having anion-exchange properties are obtained by reacting a polyalkylene-polyamine, formaldehyde (or its polymers) and a ketone, nitroalkane, or acetaldehyde until an irreversible gel is formed, the reactants being employed in the proportions of 0.7-5 mols. of the polyamine and at least 2 mols. aldehyde to each mol. of the ketone or like compound. Where a nitroalkane is used, the gel is treated with a reducing agent to reduce the nitro to amino groups. The gel is dried at temperatures partly above and below 100 DEG C. and is granulated by placing in water at a temperature dependent on the grain size required. Ketones specified are acetone, cyclohexanone, mesityl oxide. The aldehyde and ketone may be first condensed and the polyamine then added. In examples: (1) 97 pts. 37 per cent formaldehyde are mixed with 11.6 pts. acetone with cooling; 55 pts. tetraethylene pentamine are then added, gelation occurring as the last of the base is added. The gel is broken up and dried for 24 hours at 60 DEG C. and for 24 hours at 100 DEG C. and then washed free of alkali. The gel has an acid removal capacity of 885 milliequivalents per litre. U.S.A. Specification 2,259,169 is referred to. The Specification as open to inspection under Sect. 91 also described the formation of a gel by reacting (a) 110 pts. glucose, 5.8 pts. acetone and 5.8 pts. tetraethylene pentamine in presence of aqueous hydrochloric acid; (b) as above, but substituting furfural for formaldehyde. This subject-matter does not appear in the Specification as accepted. |
