Patent GB-742369-A (GB)
Title: Improvements in or relating to manufacture of lubricating greases
IPC: C10M169/00
Filed: 1953-04-09
Abstract: High molecular weight fatty acids are made by fusing a C10-C30 primary aliphatic alcohol or a mixture containing a major proportion of such alcohols, with caustic alkali, at 450-650 DEG , preferably 500-560 DEG  F.  Preferably the fusion is effected in the presence of a mineral lubricating oil. Caustic soda and potash are specified.  A preferred starting alcohol is one obtained as a product or by-product, e.g. the bottoms, in the oxo-synthesis using e.g. polymerized olefines, Fischer-Tropsch olefines or olefines from cracked waxes or petrolatums.  When using oxo-synthesis bottoms non-reactive ingredients such as hydrocarbons, acetals and ethers may be distilled off during fusion or the fusion effected under pressure so that these compounds remain in the final product.  Esters and acids present in the bottoms are saponified and neutralized respectively during fusion.  Settling of alkali in the oil-alcohol mixture during fusion is prevented by the addition of solid suspending agents such as a soap of a high molecular weight fatty acid, silica gel, carbon black, bentones, Attapulgus clay modifications and reaction products of Montmorillanite clay and long-chain aliphatic ammonium salts.  Soaps, especially sodium, of high molecular weight fatty acids are preferred although since they usually melt at below 400 DEG  F. they are preferably used as a complex with an alkali metal salt of a low molecular weight fatty acid.  The soap complexes are preferably made by neutralization of the corresponding acids in the alcohol-oil mixture with aqueous caustic alkali before fusion at higher temperature after driving off the water.  High molecular weight acids specified for soap formation are hydrogenated fish oil acids and C12-C22 naturally occurring animal or vegetable acids and they may be present in amounts of 2-30 weight per cent based on finished product.  Low molecular weight acids specified for salt formation are acetic, furoic and acrylic acids and they are used in quantities of 1-10 weight per cent based on finished product.  In these cases the finished product is a grease comprising a lubricating oil, the high molecular weight acids of the invention and the above soap-salt complex c.f. Group III.  For complex formation instead of acids the corresponding esters may be used as starting materials alkali fusion then being required to convert their alcoholic residues into acids.  When esters of low molecular weight alcohols are present pressure is required to prevent volatilization of the alcohols.  Alternatively esters of non-volatile low molecular weight alcohols may be used, e.g. sorbitol and glycol acetates.  High molecular weight acids or esters used in complex formation may be obtained from oxo processes.  A portion of the product of the alkali fusion process of the invention may be recycled to the fusion stage to act as a complex forming agent.  After fusion in a mineral oil medium the acid may be recovered as its alkali metal salt by water extraction, isolated after acidification of the aqueous extract and purified by vacuum distillation.  In examples (1) a C13 oxo alcohol is added to a mixture of sodium and potassium hydroxides in white oil at 460-530 DEG  F., the product poured into water, extracted with heptane and the C13 acid recovered on acidification of the aqueous residue and purified by distillation; in (2) a mixture of a C13 oxo alcohol and hydrogenated fish oil acids in a naphthenic lubricating oil is heated to 150 DEG  F., acetic acid added together with a 40 per cent aqueous caustic soda solution and the mass heated at 300 DEG  F. to convert the acids to soaps and salts and to drive off water, more lubricating oil is then added and fusion effected by heating the mixture at 550-560 DEG  F.; in (3) and (4) instead of the C13 alcohol of (2) a C16 oxo-synthesis alcohol and stearyl alcohol are used respectively.ALSO:A lubricating grease is made by fusing a C10-C30 primary aliphatic alcohol, or a mixture containing a major proportion of such alcohols, with caustic alkali, at 450-650 DEG F, preferably 500-560 DEG F., and dispersing the alkali metal soap thus formed in a lubricating oil so that a grease is obtained.  Caustic soda and potash are specified.  Mineral lubricating oils are preferred.  Preferably the fusion is effected in the presence of the lubricating oil so that a grease results.  A preferred starting alcohol is one obtained as a product or byproduct e.g. the bottoms in the oxo-synthesis using e.g. polymerized olefins, Fischer-Tropsch olefines or olefines from cracked waxes or petrolatums.  When using oxo-synthesis bottoms non-reactive ingredients such as hydrocarbons, acetals and ethers may be distilled off during fusion or the fusion may be conducted under pressure so that these compounds remain in the final product as modifiers.  Esters and acids present in the bottoms are saponified and neutralized respectively during fusion.  Settling of alkali in the oil-alcohol mixture during fusion may be prevented by the presence of a solid suspending agent desirably one which is a grease thickener e.g. a soap of a high molecular weight fatty acid, silica gel, carbon black, Attapulgus clay modifications and reaction products of Montmorillanite clay and long-chain aliphatic ammonium salts.  Soaps, especially sodium, of high molecular weight, fatty acids are preferred although since they usually melt below 400 DEG F. they are preferably used as a complex with an alkali metal salt of a low molecular weight fatty acid.  The soap complexes are preferably made by neutralisation of the corresponding acids in the alcohol-oil mixture with aqueous caustic alkali before fusion at higher temperature after driving off water.  High molecular weight acids specified for soap formation are hydrogenated fish oil acids and C12-C22 naturally occurring animal or vegetable acids and they may be present in amounts of 2-30 weight per cent based on finished product. Low molecular weight acids specified for salt formation are acetic, furoic and acrylic acids and they are used in quantities of 1-10 weight per cent based on finished product.  For soap complex formation instead of acids the corresponding esters may be used as starting materials, alkali fusion then being required to convert their alcoholic residues into acids.  When esters of low molecular weight alcohols are present pressure is required to prevent volatilization of the alcohols. Alternatively, esters of nonvolatile low molecular weight alcohols may be used e.g. sorbitol and glycol acetates.  High molecular weight acids or esters used in complex formation may be obtained from an oxo-synthesis.  A portion of the product of the alkali fusion process of the invention may be recycled to the fusion stage to act as a complex forming agent.  Soaps of high molecular fatty acids and/or the soap complexes described above may be included in the final grease composition even when not used as suspending agents.  Other conventional additives may be present.  The consistency of greases prepared for mineral lubricating oils may be adjusted by the addition of synthetic oils such as di-2-ethyl hexyl sebacate and adipate, polyglycol type oils, esters of dibasic acids and polyhydric alcohols, alkyl silicates, carbonates, formals and acetals.  The oil base preferably comprises 5-95 per cent of the total weight of the finished grease.  After fusion in a mineral oil medium the acid may be recovered by water extraction and purified prior to grease formation by addition to a lubricating-oil together with other high or low molecular weight fatty acids and grease additives followed by treatment with caustic alkali under conventional grease-forming conditions.  The soap derived from the alcohol by alkali fusion comprises at least 20, preferably about 30-50, weight per cent of the grease thickener or 2.0-20 weight per cent of the finished grease.  The proportion of soap derived from alcohol to soaps and salts of other acids may be 1 : 4 to 4 : 1 and is preferably about 1:1.  In Example (1) a C13 oxo alcohol is added to a mixture of sodium and potassium hydroxides in white oil at 460-530 DEG F., the product poured into water, extracted with heptane and the C13 acid recovered on acidification of the aqueous residue is purified by distillation before incorporation in a grease.  The grease is made by heating a mixture of the acid and hydrogenated fish oil acids in a naphthenic lubricating oil to 150 DEG F., adding acetic acid and 40 per cent aqueous sodium hydroxide solution and after soap formation and dehydration at gradually increasing temperature further quantities of oil are added at 480 DEG F. together with phenyl alpha naphthylamine to yield on cooling a short-fibre grease the consistency of which is changed after the addition of more naphthenic lubricating oil at 400 DEG F.  In Example (2) a mixture of a C13 oxo alcohol and hydrogenated fish oil acids in a naphthenic lubricating oil is heated to 150 DEG F., acetic acid added together with 40 per cent aqueous sodium hydroxide solution and the mass heated at 300 DEG F. to convert acids to soaps and salts and to drive off water.  More lubricating oil is then added and fusion effected by heating the mixture at 550-560 DEG F., the product being cooled to 300 DEG F. for the addition of phenyl alpha naphthylamine and to yield a grease after further cooling to 200 DEG F. which may be rendered softer by the addition of an oil.  Examples (3) and (4) are similar to Example (5) except that the alcohols used are respectively a C16 oxo synthesis alcohol and stearyl alcohol.