GB845363A - Polymers of hydrolysis products of hydrocyanic acid and compositions containing the same - Google Patents

Abstract

Water-insoluble polymerized hydrocyanic acid is partially or completely hydrolysed with an aqueous solution of a non-oxidising acid or of an alkali at 25-200 DEG C. The hydrolysis may be represented: - <FORM:0845363/III/1> where X is H or a salt forming cation, preferably alkali metal or ammonium. The hydrolysis product is a mixture of the two substances with the second predominating. Liquid HCN at least 95%, preferably anhydrous, is polymerized at 20-30 DEG C. at atmospheric pressure under reflux in the presence of an alkaline reacting catalyst, say 0.1-10%, of e.g. methylamine, trimethylamine, ethylamine, triethylamine, tri-n-butylamine, n-propylamine, aniline, toluidine, benzylamine, naphthylamine, hydrazine, potassium or sodium hydroxide or carbonate, or ammonium hydroxide. Excess HCN evaporates and the solid polymer is dried. The polymer is hydrolysed by refluxing at 25-200 DEG C. with sulphuric or hydrochloric acid, or alkali metal or ammonium hydroxide. The hydrolysed polymer is recovered as an aqueous solution from which solid is recovered by evaporation. A minor amount of the hydrolysed polymer or the metal or ammonium salt thereof may be used as a dispersing or deflocculating agent for dispersions of finely divided solid e.g. pigments, clays, adhesives, or cement, in aqueous media. 0.5-5% of the hydrolysed polymer or salt may be added to pigment dispersions in paint processing and may be incorporated as an aqueous solution or solid and may be added during milling or simultaneous mixing and dispersion. Pigments referred to are :- ferric oxide, iron blues, red lead, basic lead carbonate or sulphate, lead chromate, zinc oxide, chromate, or sulphide, lithopone, chromium oxide, titanium oxide (anatase and rutile), antimony oxide, cadmium sulphide, lead titanate, titania coated barium sulphate or calcium carbonate, zinc sulphide coated magnesium carbonate, or mixtures of lead chromate and oxide (chrome orange), or of iron blue and lead chromate (chrome green). Examples III, IV, V and VIII refer to aqueous dispersions of titanium dioxide, zinc oxide, kaolin, and soot respectively. 1-4 lbs. of the hydrolysed polymer may be added to a 42 gal. barrel of drilling mud consisting of a dispersion of clay, e.g. bentonite or mediumyield clays, in fresh or salt water, or in an oil in water emulsion, which may also contain weighting materials, e.g. barytes, iron oxide, calcium carbonate, or silica, and other additions, e.g. caustic alkali, quebracho, lime, cement, or gypsum. Examples VI and VII refer to drilling muds containing Tennessee Ball clay, bentonite, and Dixie Bond clay dispersed in fresh and salt water respectively. Specification 456,151 is referred to.