GB818323A - Process for the preparation of oil-soluble basic organic acid salts containing as cations two or more different metals - Google Patents

Abstract

Lubricants and liquid fuels comprise a major proportion of a lubricating oil or liquid fuel and a minor proportion by weight of an oil-soluble basic organic acid salt containing as cations two or more different metals. The latter is prepared by reacting an oil-soluble metal salt of an organic acid, dissolved in an oil (defined as an inert liquid with a dielectric constant of 10 or less), in the presence of water and/or a watermiscible oxygen-containing organic liquid, with an oil-insoluble compound of another metal, which is formed in situ in the reaction mixture (see Group IV (b). Suitable organic acids from which the oil-soluble salt may be derived include sulphonic acids derived from aliphatic, cycloaliphatic, aromatic or alkyl-aromatic hydrocarbons, the latter having preferably at least 12 carbon atoms in the alkyl group, and especially petroleum sulphonic acids; alkylated aromatic carboxylic acids, such as alkylsalicylic acids containing at least 12 carbon atoms in the alkyl chain, and cycloaliphatic carboxylic acids such as petroleum naphthenic acids; and phosphorus and thio-phosphorus acids derived from tri- and penta-valent phosphorus. Suitable solvent "oils" for the reaction include aliphatic and aromatic hydrocarbons. A lubricating oil, preferably of viscosity 100 to 400 S.S.U. at 38 DEG C., may be used, when it is not necessary to remove the solvent in preparing lubricating oil compositions. The basic salts may contain monovalent metals, such as sodium, potassium and lithium, polyvalent metals, such as the alkaline earth metals (especially calcium), magnesium, zinc, lead, aluminium, copper, tin, cobalt, nickel and manganese or ammonium. In examples: (1) a mixture of mono- and di-C14-18-alkylsalicylic acids containing the corresponding alkylphenols is dissolved in xylene, neutralized with methanolic NaOH, CoCl2 added to convert the resulting sodium salt to the cobalt salt, the methanol distilled off and the solution filtered; lime is added with more xylene and methanol and CO2 introduced into the solution at 60 DEG C.; the methanol is distilled off and the solution filtered; lubricating oil is added to the filtrate and the xylene removed in vacuo giving a lubricating oil solution containing a cobalt alkylsalicylate/calcium carbonate basic salt; (2) and (3) similar solutions of nickel alkyl-salicylate/calcium carbonate and calcium alkyl-salicylate/sodium carbonate are prepared. Specifications 785,196, 790,471 and 818,326 are referred to.ALSO:Oil-soluble basic organic acid salts containing as cations two or more different metals, are made by reacting an oil-soluble metal salt of an organic acid, dissolved in an oil as defined below, in the presence of water and/or a water-miscible oxygen-containing organic liquid, with an oilinsoluble compound of another metal, which is formed in situ in the reaction mixture. The products are of the type RpMeq.xMe1rZs, where Me and Me1 are different metals, RpMeq is an oil-soluble salt of an organic acid, R being an organic acid radical, Me1rZs is an oil-insoluble metal compound such as a metal oxide, hydroxide or carbonate, and x is an arbitrary number, not necessarily integral. More than one compound of the type Me1rZs may be present in a given basic salt. The oil-soluble metal salt may be derived from various classes of organic acids, such as sulphonic acids, carboxylic acids and phosphorus-containing acids. The sulphonic acids may be derived from aliphatic, alicyclic, aromatic or alkylaromatic hydrocarbons, this last class preferably containing at least 12 carbon atoms in the alkyl chain. A particular class of sulphonic acids is constituted by the petroleum sulphonic acids. Examples of suitable carboxylic acids are alkylated aromatic carboxylic acids containing a relatively long alkyl chain, such as the alkylsalicylic acids containing 12 or more carbon atoms in the alkyl substituent, and alicyclic carboxylic acids, such as petroleum naphthenic acids. Phosphorus-containing acids may be derived from tri- or pentavalent phosphorus; the corresponding thio acids also must be considered. The salt is not necessarily a neutral salt, but may be a basic salt prepared according to the invention or otherwise. Thus a salt may have its basicity increased by repeated treatments by the method of the invention. The oil-soluble organic acid salt used as the starting material may be first formed in situ in the reaction mixture by reacting the free organic acid or a salt thereof with a compound of the desired metal such as an oxide, hydroxide, carbonate or chloride. If desired the starting material may be a mixture of oil-soluble metal salts of organic acids. An oil is defined as an inert liquid having a dielectric constant of 10 or less, and includes in particular liquid hydrocarbons such as benzene, toluene, xylene, pentane, heptane and petroleum fractions from gasoline up to lubricating oil fractions, preferably with not too high a viscosity, for example 100 to 400 S.S.U. at 38 DEG C. The concentration of the starting material in the solution is generally from 10 to 70 per cent by weight. Specific classes of suitable oxygen-containing organic liquids are aliphatic alcohols, ethers, and esters. Water used alone should be at least 2 per cent and the oxygen-containing liquid used alone at least 5 per cent by weight, based on the solution of the oil-soluble metal salt. The reaction mixture may be homogeneous or in two separate phases. The formation of an oil-insoluble metal compound can be effected, for example, by adding Ca(OH)2 or NaOH (in the dry state or in aqueous or alcoholic solution or suspension) to the reaction mixture and passing CO2; or by reacting NaOH with CaCl2 or Ca(NO3)2. The reaction is generally carried out at a temperature between 20 DEG and 150 DEG C. and may be carried out at atmospheric pressure or higher. After reaction the water and/or water-miscible oxygen-containing liquid may be removed, followed by the solvent to obtain the basic organic salt in the free state. The basic salts may contain monovalent metals such as Na, K and Li, and including ammonium, and polyvalent metals such as the alkaline earth metals (especially Ca), Mg, Zn, Pb, Al, Cu, Sn, Co, Ni and Mn. The compounds may be used as detergent additives for lubricating oils and also in the preparation of biocides, in particular fungicides and wood preservatives; as well as for the preparation of paint driers, catalysts and the like. In examples: (1) a mixture of mono- and di-C14-18-alkylsalicylic acids containing the corresponding alkylphenols is dissolved in xylene, neutralized with methanolic NaOH, CoCl2 added to convert the resulting sodium salt to the cobalt salt, the methanol distilled off and the solution filtered; lime is added with more xylene and methanol, the solution is heated to 60 DEG C. and CO2 introduced with stirring; the methanol is distilled off and the solution filtered; lubricating oil is added to the filtrate and the xylene removed by vacuum distillation, giving a lubricating oil solution of a cobalt alkylsalicylate/calcium carbonate basic salt; (2) a nickel alkylsalicylate/calcium carbonate basic salt is prepared in a similar manner; (3) a calcium alkylsalicylate/sodium carbonate basic salt is prepared in a similar manner. Specifications 785,196, 790,471 and 818,326 are referred to.