GB417340A - Improvements in the manufacture and production of sols and highly dispersed suspensions containing oxidic metal compounds - Google Patents

Abstract

Colloidal sols or highly dispersed suspensions of oxidic metal compounds are obtained by reacting alkylene oxides on solutions of salts of heavy metals or earth metals and removing the glycol ester formed together with unreacted alkylene oxide before substantial formation of an irreversible precipitate sets in. The reaction may be carried out between zero and 150 DEG C., but preferably between 15 and 30 DEG C. The metal salts may be dissolved in water and in organic solvents such as ethyl alcohol or glycerol which should preferably contain water. The salts of tri- and tetra-valent metals form oxide sols where as salts of divalent metals usually form suspensions of oxidic compounds such as oxychlorides, for example, cupric chloride gives copper oxychloride and if other metal salts are present, the metal hydroxide sols thus formed act as peptising agents for the copper oxychloride. The alkylene oxides used must be soluble to some extent in the solvent used for the reaction, and in aqueous media those containing 2--4 carbon atoms are preferred. Alpha-olefine oxides such as ethylene oxide are suitable. The glycol ester and unchanged alkylene oxide may be removed by extraction with organic solvents immiscible with water e.g. ether, benzene, chloroform, carbon tetrachloride or ethylene dichloride, or by distillation, preferably under reduced pressure, the temperature being about 100 DEG C. and not exceeding 150 DEG C. In the latter case, the products are preferably evaporated to dryness and then taken up in water or other suitable liquid. Numerous examples describe the preparation of sols or dispersions of aluminium oxide; mixed oxides or hydroxides of iron and aluminium; tin dioxide containing basic tin chloride; zirconium oxide; chromium oxide; thorium dioxide which is reversibly soluble; copper oxychloride; copper oxychloride and aluminium oxide; zinc oxychloride or mixture with zine oxide; and palladium oxide.