GB795172A - Improvements in and relating to the preparation of basic polyvalent metal salts of organic acids - Google Patents

Abstract

Polyvalent metal basic salts of organic acids are prepared from (a) an oil solution of a neutral or basic polyvalent metal salt of an organic acid, the term "oil" denoting any inert water-immiscible liquid; (b) an aqueous solution of an alkali-metal carbonate; and (c) an aqueous solution of a water-soluble polyvalent metal salt, by a process comprising mixing solution (a) with solution (b) or (c) to form a water-in-oil dispersion, subsequently mixing solution (c) or (b) respectively with the dispersion to form a polyvalent metal carbonate in situ and then removing the water and any undissolved solid material from the oil phase. In a modification, the starting material (a) is an oil solution of an organic acid or a salt thereof other than a polyvalent metal neutral or basic salt, e.g. an alkali metal, ammonium or organic base salt, and the water-soluble salt of a polyvalent metal is used in such proportion as to convert the organic acid or salt thereof to the corresponding polyvalent metal neutral salt as well as to form the polyvalent metal carbonate. The product may be used again in the process as solution (a) to obtain a product of greater basicity. The process may be effected at between 60 DEG and 120 DEG C., elevated pressure being used at the higher temperatures to maintain a liquid reaction mixture. The two aqueous solutions may be added to the oil solution one after the other, or simultaneously in such a way that they do not contact one another before being dispersed in the oil. The alkali metal carbonate and water-soluble polyvalent metal salts may be reacted in an equal number of equivalents, say 1 to 20, with the polyvalent metal neutral or basic salt of the organic acid; preferably, however, a small excess of the water-soluble polyvalent metal salt is used. The subsequent separation of the oil and any aqueous phases may be facilitated by addition of an oxygen-containing organic solvent or with the aid of a surface-active agent. The products, which may be isolated from their solutions by removal of the oil, may have a basicity of up to 1500 per cent or more and contain the excess polyvalent metal in the form of its carbonate; a modified form of product in which the excess metal is present both as carbonate and hydroxide is obtained by adding some alkali metal hydroxide to solution (b) containing the alkali metal carbonate. The oil for solution (a) may be a hydrocarbon oil, e.g. a kerosine, gas oil, diesel oil, lubricating oil or a residual fuel oil, polymerized olefines, alkylated aromatic hydrocarbons, liquid polysiloxanes and fluorocarbons, fatty oils such as castor oil, synthetic-ester lubricating oils such as trioctyl phosphate and di-(2-ethyl hexyl) sebacate or adipate, benzene, xylene, cyclohexane, iso-octane, decyl alcohol and diamyl ether. The organic acids may be carboxylic acids including among others specified, palmitic, oleic, hydroxy and chlorostearic acids, nitrolauric acids, stearyl benzoic acids, paraffin wax-substituted naphthoic acids, alkyl-substituted salicylic acids, petroleum naphthenic acids, di-octyl cyclo-pentane carboxylic acids and di-lauryl decahydronaphthalene carboxylic acids; sulphonic acids such as petroleum sulphonic acids and various alkylated aromatic and cyclo-aliphatic sulphonic acids, e.g. cetyl chlorbenzene, dilauryl-beta-naphthol and cetyl phenol mono- and di-sulphide sulphonic acids; partial esters of phosphorus oxy- or thio-acids, e.g. di-capryl dithiophosphoric acid and di (methyl cyclohexyl) dithiophosphorous acid; and sulphamic, sulphinic or thiosulphonic acids and acid esters of sulphuric acid. The polyvalent metal salts used in aqueous solution (c) may be the chlorides, nitrates, sulphates, acetates or formates. The polyvalent metals present in solutions (a) and (c) may be, for example, alkaline earth metals, magnesium, zinc, copper, iron, nickel, cobalt, chromium, manganese or lead. The basic products may be used as additives for lubricating or fuel oils (see Group III). In typical examples: (1) a 10 per cent solution of sodium naphthasulphonates in mineral lubricating oil and a 20 per cent aqueous sodium carbonate solution are passed continuously at 95 DEG C. through a pipe and then a globe valve, to ensure dispersion of the aqueous phase in the oil phase; a heated 20 per cent aqueous solution of calcium chloride is continuously fed into the issuing dispersion which is then passed through another globe valve into a series of settlers; the separated oil phase of basic calcium petroleum sulphonates is removed and, if desired after being washed with aqueous calcium chloride solution to remove residual alkali metal, is dried and filtered; (2) a mineral lubricating oil solution of naphtha sulphonic acids is mixed with an aqueous calcium chloride solution containing sufficient suspended lime to neutralize the acids; aqueous sodium carbonate solution is then stirred into the resulting water-in-oil dispersion and thereafter the mixture is settled and the oil layer separated, dried and filtered; (3) an aqueous solution of sodium naphthenates is added to a marine diesel oil, at 80-90 DEG C., whereby the naphthenates transfer to the oil phase; an aqueous solution of sodium carbonate and hydroxide is stirred in to form a water-in-oil dispersion to which an aqueous solution of magnesium chloride is added slowly with stirring followed by some "Teepol" (Registered Trade Mark); the mixture is settled and the oil phase containing basic magnesium naphthenates worked up as in (2); (4) a xylene solution of mono- and di-lauryl hydrogen phosphates is neutralized with aqueous caustic soda, an aqueous solution of sodium carbonate is dispered in the oil and then an aqueous ferric chloride solution is added; an oil-solution of basic ferric lauryl phosphates is recovered as in (2). Specifications 586,461 and 790,471 are referred to.ALSO:Lubricating oils and fuel oils comprise, as detergent additives and corrosion inhibitors respectively, polyvalent metal basic salts of organic acids prepared from (a) an oil solution of a neutral or basic polyvalent metal salt of an organic acid, the term "oil" denoting any inert water-immiscible liquid; (b) an aqueous solution of an alkali metal carbonate; and (c) an aqueous solution of a water-soluble salt of a polyvalent metal by mixing solution (a) with solution (b) or (c) to form a water-in-oil dispersion, subsequently mixing solution (c) or (b) respectively with the dispersion to form a polyvalent metal carbonate in situ and then removing the water and any undissolved solid material from the oil phase (see Group IV (b)). The salt in oil solution (a) may be formed in situ from the free acid or a salt other than a neutral or basic polyvalent metal salt thereof. The excess of polyvalent metal in the basic salt product is normally present as metal carbonate; if some alkali metal hydroxide is added to solution (b) the basic final product contains the excess of polyvalent metal as hydroxide and carbonate. The basic salts are normally added to the lubricating or fuel oils without being isolated from the oil in which they are formed. This oil is generally the same as that in which the additive is to be used but may also be another hydrocarbon such as polymerized olefines, alkylated aromatic hydrocarbons, benzene, cyclohexane or iso octane or a fatty oil, e.g. castor oil, a liquid polysiloxane or fluoro carbon, diamyl ether or a synthetic ester-type lubricating oil. The additives may be alkaline earth metal zinc, magnesium, copper, iron, nickel, cobalt, chromium, manganese or lead basic salts of carboxylic acids including fatty acids, substituted fatty acids, naphthenic acids and alkyl substituted aromatic or cyclo aliphatic carboxylic acids, e.g. alkylated salicylic acids, petroleum sulphonic acids, alkylated aromatic and cycloaliphatic sulphonic acids and acid esters of sulphuric acid and oxy- and thiophosphorus acids. Examples describe mineral lubricating oil solutions of basic calcium naphtha sulphonates, a marine diesel oil solution of basic magnesium naphthenates and xylene solutions of basic calcium naphthenates or basic ferric mono- and di-lauryl phosphates. Specifications 586,461 and 790,471 are referred to.