GB562403A - Process of preparing ion exchange compounds and compounds obtained thereby - Google Patents

Abstract

Anion exchange compounds are prepared by co-condensing guanyl area or a salt thereof and urea and/or an aminotriazine with formaldehyde forming a gel of the resulting product, grinding, drying and curing resulting gel. The term urea is defined as including thiourea and alkyl ureas, and the term aminotriazine as including melamine and similar compounds, e.g. 2,4,6-triethyl and triphenyl triamino-1,3,5-triazine, and guanamines, e.g. formoguanamine, and lauroguanamine and 2-amino-1,3,5-triazine or commercial mixtures of the various aminotriazines, for example, the product obtained by heating dicyandiamide sufficiently to obtain some melamine together with other reactive aminotriazines. The guanyl urea may be used as sulphate, nitrate, acetate, formate, phthalate, benzoate and chloride. The molal ratio of guanyl urea to urea or aminotriazine should preferably be between 1 : 1 and 1 : 4. Examples 1 to 6 describe the preparation of ion exchange compounds by refluxing on a steam bath mixtures containing urea, guanyl urea salts, formalin and sodium carbonate and forming a gel by addition of acid. The gel is ground, dried, washed and cured by heating. Example 8 describes a similar preparation using melamine in place of urea and example 9 describes the preparation of ion exchange compounds from urea, guanyl urea and formalin. The products are useful for water softening, removal of acid from water or alcoholic solutions and purification of sugar juices. One cubic foot of resin can extract acid equivalent to 4,000 to 10,000 grains of calcium carbonate from fluid media. The resins may also be used for the extraction of acid from vapours. Exhausted beds of the resin may be regenerated by the action of alkaline solutions followed by washing. Specifications 561,896 and 562,402 are referred to. The Specification as open to inspection under Sect. 91 describes also the use with the urea or resin of acetaldehyde, propionaldehyde, cinnamyl aldehyde, or furfural in place of formaldehyde. Phenol or cresol formaldehyde condensation products may be used in place of the urea aldehyde or aminotriazine aldehyde resins and phenol, aniline, phenylene diamine, dicyandiamide, guanidine and its salts or derivatives may be used together with the guanyl urea. This subject-matter does not appear in the Specification as accepted.