Improvements in or relating to methods for reducing the surface tension of liquids

摘要

A process for reducing the surface tension of liquids comprises adding to the liquid a perchlorofluorocarboxylic acid of formula Z(CF2-CFCl)n - 1 CF2COOH wherein Z is chlorine or a perhalomethyl radical having a molecular weight not above 146.5 and n is 2-16, or an ammonium or metal (e.g. sodium, potassium, copper, aluminium or ferric) salt thereof. In Example (12) an emulsion polish is obtained by mixing and heating carnauba wax with a solution of Cl(CF2-CFCl)3CF2COONH4 in water until a homogeneous mixture is obtained. In Example (13), a paste polish comprises a mixture of carnauba wax, beeswax paraffin, mineral spirit and Cl(CF2CFCl)3CF2COONH4 Specifications 784,727 and 827,378 are referred to.ALSO:A process for reducing the surface tension of organic sulphonating, oxidizing, or nitrating liquids comprises adding to the liquid a perchlorofluorocarboxylic acid, which may be of formula Z(CF2-CFCl)n-1CF2COOH wherein Z is chlorine or a perhalomethyl radical having a molecular weight not above 146.5, and n is 2-16, or an ammonium or metal (e.g. sodium, potassium, copper, aluminium or ferric) salt thereof. In Example (9), benzene is nitrated with sulphuric and nitric acids in the presence of Cl(CF2CFCl)3CF2COOH under reflux. The lower acid layer is eventually removed and the nitrobenzene washed with water and dilute sodium hydroxide. In Example (10), tert.-butylbenzene is sulphonated with oleum in the presence of Cl(CF2CFCl)3CF2COOH, the mixture poured into water, neutralized with sodium bicarbonate, salted out and washed with salt solution to obtain sodium p-tert.-butylbenzene sulphonate. In Example (11) benzoin is oxidized under reflux to benzil by means of nitric acid in the presence of Cl(CF2-CFCl)3-CF2COOH. The reaction mixture is poured into water and the yellow solid melted with dilute sodium carbonate solution to purify it. Specifications 784,727 and 827,378 are referred to.ALSO:A process for reducing the surface tension of metal electroplating, pickling and etching baths, ore flotation baths and organic sulphonating, oxidizing, or nitrating liquids comprises adding to the liquid a perchlorofluorocarboxylic acid which may be of the formula Z(CF2-CFCl)n-1CF2COOH wherein Z is chlorine or a perhalomethyl radical having a molecular weight not above 146.5 and n is 2-16, or an ammonium or metal (e.g. sodium, potassium, copper, aluminium or ferric) salt thereof. Specifications 784,727 and 827,378 are referred to.ALSO:A process for reducing the surface tension of pickling and etching baths and ore flotation baths comprises adding to the liquid a perchlorofluorocarboxylic acid, which may be of the formula: Z(CF2-CFCl)m-1CF2COOH where in Z is chlorine or a perhalomethyl radical having a molecular weight not above 146.5 and n is 2-16, or an ammonium or metal (e.g. sodium, potassium, copper, aluminium or ferric) salt thereof. The free acid may be used in sulphuric, hydrochloric or hydrofluoric acid pickling baths for iron or steel, and in scaling dip and bright dip baths for brass containing aqueous mixtures of hydrochloric, sulphuric and nitric acids. In bright dips for cadmium coatings the acid may be added to an aqueous mixture of chromic and sulphuric acids. Before being copper-plated, aluminium may be pretreated in dipping baths containing free acid, sodium hydroxide, zinc oxide, potassium cuprocyanide, and sodium sulphite. In Example (7), etching solutions for various metals are as follows: (a) for zinc, Cl(CF2CFCl)nCF2COONa and either copper sulphate and sodium bisulphate, or ferric chloride, acetic acid, nitric acid, and chromium trioxide; (b) for iron and steel, nitric and acetic acids and Cl(CF2-CFCl)nCF2COONa; (c) for copper and brasses, ammonia, hydrogen peroxide, and Cl(CF2-CFCl)nCF2COONH4; (d) for aluminium and aluminium alloys, hydrochloric, nitric and hydrofluoric acids and Cl(CF2-CFCl)nCF2COONa; (e) for nickel and nickle alloys, nitric and acetic acids and Cl(CF2-CFCl)nCF2COONH4; and (f) for gold, silver, platinum and other noble metals, nitric and hydrochloric acids and Cl(CF2-CFCl)CF2COONH4. In all cases n=2.5. Salts of the perchlorofluorocarboxylic acids are selective ore flotation agents and may be used in conjunction with collectors such as xanthates, mercaptans, organic sulphides, thiophosphates, thiocarbonates, thiourea, thiocarbanilide, azo- and diazo-compounds, with activating and conditioning agents such as copper sulphate and other salts of copper, lead and zinc, alkali metal sulphides and silicates, lime and sodium hydroxide, carbonate, and cyanide, inhibitors such as glue, starch, gelatin and tannin, and frothers such as pine oil, cresylic acid, and alcohols. In Example (8), copper sulphide ore is ground with lime and water, and conditioned with sodium sulphide. Water is added together with Cl(CF2-CFCl)3CF2COONa, cresylic acid and sodium dithiophosphate and air is drawn through the pulp, the concentrate being scraped off. Specifications 784,727 and 827,378 are referred to.