Patent GB-806915-A (GB)
Title: Complex metal salts of oxidised petroleum oils
IPC: C10M159/20
Filed: 1955-06-14
Abstract: Mineral lubricating oils comprise as detergent additives minor amounts of oil solutions of complex metal salts obtained by (1) forming a mixture of a petroleum oil having an average molecular weight of about 300-1000 and about 2-25 per cent, based on the weight of oil, of an hydroxide of a Group II metal; (2) oxidizing the oil in the mixture with a free-oxygen-containing gas at about 250-600 DEG F., the reaction time being sufficient to effect reaction of about 5-85 per cent by weight of the metal hydroxide with the oxidized oil; (3) providing a mixture comprising unchanged petroleum oil solution of oxidized oil-metal hydroxide reaction product formed in step 2, a Group II metal hydroxide to the extent of at least about 2 per cent up to about 40 per cent by weight of the oil used to prepare in step 2 the oil solution used in this step, and water at a temperature below the boiling-point of water; (4) substantially completely dehydrating the resulting mixture; and (5) filtering the dehydrated mixture to separate the oil solution of complex metal salt (see Group IV (b)).  The detergent solutions described in the examples are prepared from refined Mid-Continent bright stocks (average M.W. 720 or 880) or an East Texas heavy waxy distillate stock (M.W. 470); in most cases calcium hydroxide is used in both steps 1 and 3, being sometimes the unchanged hydroxide present at the end of the oxidation, but in one case calcium hydroxide is used in step 1 and barium hydroxide in step 3.  These solutions, which as exemplified, contain from 1.7 to 7.2 per cent by weight of Group II metal, may be used in amounts of from about 1-10 per cent by weight of the lubricating oil, if desired in conjunction with other additives such as anti-oxidants, pour-point depressants, V.I. improvers, defoamants and rust preventatives.  Comparisons are made between the lubricating properties of an SAE20 base oil containing a pinene-P2S5 reaction product as an antioxidant and either one of the detergent oil solutions mentioned above or the corresponding intermediate oil solution obtained at the end of the oxidation step and filtered.ALSO:Oil solutions of complex metal salts of oxidized petroleum oil are prepared by (1) forming a mixture comprising a petroleum oil having an average M.W. of from about 300 to about 1000 and about 2 to about 25 per cent, based on the weight of oil, of an hydroxide of a metal of Group II; (2) contacting the mixture with a free-oxygen containing gas at a temperature of from about 250 DEG  to about 600 DEG  F., to effect oxidation of the oil, the reaction time being sufficient to effect reaction of from about 5 to about 85 per cent by weight of the metal oxide with the oxidized oil; (3) providing a mixture comprising oxidized oil-metal hydroxide reaction product in unchanged petroleum oil produced in step 2, a hydroxide of a Group II metal to the extent of at least 2 per cent up to about 40 per cent, based on the weight of oil used to prepare the amount of oil solution of reaction product which is used in this step, and water at a temperature below the boiling-point of water; (4) substantially completely dehydrating the mixture formed in step 3; and (5) subjecting the dehydrated mixture to filtration to separate the resulting oil solution of the complex metal salt product, a diluent solvent being used, if desired, to facilitate the filtration. The oxidation may be effected with air or oxygen, preferably at about 350-450 DEG  F., and a catalyst may be present.  In forming the mixture in step (3), the required metal hydroxide may comprise unchanged metal hydroxide present at the end of the oxidation or may be added after filtration of oxidation product.  The water generally amounts to about 2 to 50 per cent by weight of the oxidation product, 2 to 10 per cent being preferred.  The dehydration may be effected by heating whilst passing nitrogen through the mixture or by azeotropic distillation, e.g. with benzene.  The products are utilizable as detergents in mineral lubricating oils (see Group III) and also as components in coating compositions, paint driers, detergent soaps, dispersants and rust-preventive compositions. In typical examples: (1) a refined Mid-Continent bright stock (M.W. 720) admixed with 7.2 per cent calcium hydroxide is airoxidized at 375 DEG  F. and the product is cooled and filtered when about half the metal hydroxide has reacted; 400 gms. of the filtrate are mixed with 135 mols. of 10 per cent aqueous Ca(OH)2 and the mixture is dehydrated at 420 DEG  F. and filtered, the filtrate then containing 2.24 per cent Ca; (3) a similar bright stock (M.W. 880) admixed with 11 per cent Ca(OH)2 is air-oxidized in like manner with about 30 per cent of the hydroxide being consumed; the unfiltered reacted mixture is then cooled, water is added and subsequently is stripped off at 400 DEG  F., yielding after filtration an oil solution containing 2.43 per cent Ca; a comparative experiment is given showing the lower Ca content obtained when the air-oxidation is effected in the absence of the metal hydroxide, the oxidation product then being diluted with toluene, mixed with water and about 20 per cent Ca(OH)2 and thereafter dehydrated and filtered; (5) the bright stock of (3) in admixture with about 22 per cent Ca(OH)2 is similarly oxidized and the product is filtered, diluted with toluene, admixed with water and barium hydroxide and then dried and filtered yielding an oil solution containing 0.73 per cent Ca and 6.5 per cent Ba.  Magnesium, strontium and zinc hydroxides are other specified metal hydroxides. An additional example uses an East Texas heavy, waxy distillate stock of M.W. 470.