Patent GB-790473-A (GB)
Title: Preparation of highly basic alkaline earth metal salts of organic acids
Inventor: WINSOR PHILIP ALAN
IPC: C10L1/14
Filed: 1955-04-29
Abstract: An oil-soluble alkaline earth metal (including magnesium) basic salt of an organic acid is prepared by mixing a colloidal dispersion of a preformed alkaline earth metal carbonate in an alkanol containing less than 6 carbon atoms in the molecule with an organic acid having at least 8 carbon atoms in the molecule or a salt thereof and removing the alkanol from the resulting mixture.  The organic acid or its salt may be added in the form of an oil solution to obtain an oil solution of the required basic salt.  Alternatively the organic acid or salt may be used in solution in an alkanol, ketone or ether, and an oil may then be added to the reactants before, during or after mixing to produce an oil solution of the basic salt.  The salts of organic acids employed may be derived from carboxylic acids, such as fatty acids having at least 12 carbon atoms in the molecule, or the hydroxy, chloroor nitro-substituted fatty acids, the aromatic carboxylic acids containing an oil-solubilizing radical, the petroleum naphthenic acids and the naphthenic acids and alkyl salicylic acids described in Specification 586,461, [Group IV], the sulphonic acids including the petroleum sulphonic acids, alkylaryl sulphonic acids, alkyl cycloaliphatic sulphonic acids and alkyl-heterocyclic sulphonic acids, cetyl chlorobenzene sulphonic acids, cetyl phenol sulphonic acids, octyl phenol monosulphide sulphonic acids; sulphamic, sulphinic, thiosulphuric, phosphonic sulphamic, sulphinic, thiosulphuric, phosphonic and phosphinic acids; or partial esters of phosphorus oxyacids or thioacids.  The salt used is preferably an alkali metal or alkaline earth metal salt but other salts such as ammonium or organic base salts, or polyvalent metal salts such as copper, iron, nickel, cobalt, chromium, manganese, lead and zinc salts may also be used.  If the free acid is used, sufficient of the alkaline earth metal carbonate must be used to convert the free acid to the salt as well as to provide the excess alkaline earth metal to give the desired basicity.  Colloidal dispersions of the alkaline earth metal carbonates in alkanols such as methanol, ethanol or proponol, may be made by passing carbon dioxide into a solution or suspension of an alkaline earth metal oxide or hydroxide in the alkanol.  Thus if lime is dispersed in methanol and carbon dioxide bubbled through, a slurry of calcium methyl carbonate is obtained which, on stirring, is hydrolysed by water (present or added) to a clear sol. of calcium carbonate. Magnesia, or barium or strontium oxide may also be used.  The mixing of the colloidal dispersion of the alkali metal carbonate with the organic acid or salt may take place batch wise or continuously and at any suitable temperature, preferably between ambient temperature and 80 DEG  C.  The alkanol is removed, for example by settling and removing as a separate phase or by distillation during or after mixing.  The salt of an organic acid which is used may itself be a basic salt.  Thus an oil solution of an alkaline earth metal, basic salt produced by the process of Specification 790,471 or 786,167 may be treated to produce a still more basic salt.  When an oil solution of the basic salt is to be produced, the oil used may be a hydrocarbon oil, such as a kerosine, gas oil, diesel oil, mineral lubricating oil or fuel oil, or synthetic lubricating oils such as polymerized olefins, alkylated aromatic hydrocarbons, liquid polysiloxanes and fluorohydrocarbons, esters such as di(2-ethylhexyl) sebacate or adipate and fatty oils such as castor oil may also be used. Waterimmiscible liquids such as benzene, xylene, toluene, cyclohexane, iso-octane, decane, decyl alcohol and diamyl ether may also be used.  When such volatile oils are used, the basic salts may be isolated from the oil solutions by removing the oil, for example by distillation.  The oil solutions of the basic salts are suitable as additives for lubricating oils.  In examples, oil solutions of highly basic (1) calcium naphthenate; (2) barium naphthasulphonate; (3) calcium naphthasulphonate, calcium/barium and calcium/magnesium naphthasulphonate, (4) barium/lithium naphthasulphonate; (5) barium/sodium and barium/zinc naphthasulphonate; and (6) calcium/potassium naphthasulphonate; and (7) magnesium/barium napthasulphonate are prepared by mixing a colloidal dispersion of an alkaline earth metal carbonate in methanol with an oil solution of an appropriate salt of an organic acid and removing the methanol.  In Example (8) a dispersion of alkyl salicylic acids in methanol; and in (9) a solution of naphthenic acid in methanol, is added to a methanolic sol. of calcium carbonate and the slurry of basic salt so produced is mixed with spindle oil, resulting in solutions of basic calcium naphthenate, respectively, in spindle oil.ALSO:Highly basic alkaline earth metal salts of organic acids having at least 8 carbon atoms in the molecule are prepared (see Group IV (b)) in solution in oils such as hydrocarbon oils, e.g. kerosine, gas oil, diesel fuel, mineral lubricating oils or residual fuel oil derived from petroleum; synthetic lubricating oils, e.g. polymerized olefines, alkylated aromatic hydrocarbons, liquid polysiloxanes and fluorocarbons; ester-type lubricating oils, e.g. di(2-ethylhexyl) sebacate or adipate, trioctyl phosphate or castor oil; or water immiscible liquids such as benzene, xylene, toluene, cyclohexane, iso-octane, decane and diamyl ether.  The oil solutions may be diluted with further quantities of oil to give oil compositions containing the said salts as additives fulfilling some function, such as that of a detergent additive in lubricating oils, or an anti-corrosion additive in residual fuel oils or an additive to prevent screen clogging in cracked fuel oils.  The oil used to prepare the solution of basic salt may be the same as or different from that to which the solution is added. The basic salt is prepared from preformed calcium, magnesium, barium or strontium carbonate and an organic acid having at least 8 carbon atoms in the molecule or a salt thereof.  The acids employed may be carboxylic, thiocarboxylic, sulphonic, sulphamic, sulphinic, thiosulphonic, phosphonic and phosphinic acids or partial esters of sulphuric acid or of phosphorus oxyacids or of phosphorus thioacids.  Many suitable acids are mentioned and in particular, additives for lubricating oils or fuel oils may be obtained from the naphthenic acids and alkyl salicylic acids described in Specification 586,461, and from oil-soluble petroleum sulphonic acids.  Oil solutions of alkaline earth metal basic salts of organic acids described in Specification 790,471 or 786,167 may be made still more basic by the process.  When preparing a highly basic calcium naphtha sulphonate it is convenient to start from a lubricating oil solution containing 5 to 50 per cent by weight, preferably 10 to 45 per cent by weight, of calcium naphthasulphonates.  Examples describe the preparation of (1) basic calcium naphthenate in xylene; mineral lubricating oil solutions of (2) basic barium naphthasulphonate; (3) basic calcium naphthasulphonate, basic calcium/barium naphtha sulphonate and basic calcium/magnesium naphthasulphonate; (4) basic barium/lithium naphthasulphonate; (5) basic barium/sodium and basic barium/zinc naphthasulphonates; (6) basic calcium/potassium naphthasulphonate; and (7) basic magnesium/barium naphthasulphonate; (8) basic calcium alkyl salicylates in spindle oil; (9) basic calcium naphthenate in spindle oil.