GB776455A - Additive compositions for lubricating oils and lubricating compositions containing them - Google Patents

Abstract

An additive composition suitable for use in lubricating oils comprises a product obtained by forming a mixture of an oil-soluble hydrocarbon sulphonic acid or an alkaline earth metal salt thereof and an alkyl phenol sulphide or alkyl thiophenol sulphide whose alkaline earth metal salts are oil soluble or an alkaline earth metal salt thereof, heating this mixture with a basic reacting inorganic alkaline earth metal compound in an amount in excess of that required to form the normal metal salt of the mixture and contacting the product so formed with an acidic reagent in an amount sufficient to neutralize at least a portion of the titratable basicity of the product. Preferred alkyl phenol sulphide or alkyl thiophenol sulphide starting materials are defined by the formula RAr(XH)-Sx-R1 and the alkaline earth metal salts thereof. Ar represents a benzene nucleus or a plurality of rings, e.g. in biphenyl or a condensed ring system, e.g. derived from alkyl naphthalene or anthracene, R is an alkyl group, X is sulphur or oxygen, x is an integer from 1 to 4 and R1 is an organic group, e.g. an aryl, alkyl, aralkyl or alkylaryl group which may contain substituent atoms or groups such as halogen, nitro, amino, hydroxy, alkoxy, aroxy, mercapto or carboxy. Especially suitable are compounds of the formula RAr(XH)-Sx-Ar(XH)R wherein R represents at least one alkyl radical attached to an aromatic nucleus Ar, the number of carbon atoms in all such radicals attached to each benzene nucleus being at least 5 where the metal complex is to be dissolved in hydrocarbon oils, X is oxygen or sulphur and x is an integer from 1 to 4. Nuclear substituents which may be present include alkyl, cycloalkyl, aralkyl, aryl, carboxyl, hydroxyl, alkoxy, aroxy, sulphydryl, nitro ester (organic and/or inorganic), keto, amino, aldehyde, chlormethyl, aminomethyl, alkyl thiomethyl, alkyl xanthomethyl. Alkaline earth metal compounds of the above may be employed. Lists of other general formul of suitable alkyl phenol- and thiophenol sulphides are furnished. Specific sulphide starting materials mentioned are tert.-octyl phenol sulphide, 2,4-di-tert.-amyl phenol sulphide, tert.-amyl phenol sulphide, 2 - hydroxy - 3,5 - di - tert. - amyl - 41 - diethyl - amino diphenyl sulphide, 2-stearoyl-4-amyl phenol sulphide, C16-C20-branched chain alkyl phenol sulphide and bis-(2,4 - diamyl phenol)-4-amyl phenol dithioether prepared from 2,4-di-tert.-amyl phenol and one mol. of p-tert.-amyl phenol, sulphurized with sulphur chloride. Oil-soluble hydrocarbon sulphonic acid starting materials are prepared by sulphonating alkyl benzenes, naphthalenes, anthracenes or picenes. Preferred sulphonate starting materials are obtained by sulphonating lubricating oils with sulphuric acids and the sulphonates may optionally be neutralized with a basic agent, e.g. sodium hydroxide or carbonate, extracted with aqueous alcohol and converted to an alkaline earth metal salt by double decomposition or the sulphonic acids may be neutralized with an oxide or hydroxide of the desired metal. Preferred sulphonates are those of calcium, strontium, barium and magnesium. The oxides, hydroxides and carbides are specified as basic reacting alkaline earth metal compounds. Acidic reagents mentioned include carbon dioxide, hydrogen halides, acidic nitrogen oxides or sulphur oxides. In examples, additives are produced when a mixture in mineral oil of alkaline calcium-barium sulphonate obtained by treating a calcium petroleum sulphonate with barium hydroxide, and tertiary octyl phenol sulphide, obtained by alkylating phenol with di-isobutylene and treating the product with sulphur dichloride in hexane, is heated with barium hydroxide and the product treated with carbon dioxide whilst heating (I); in similar processes mineral oil mixtures of neutral calcium petroleum sulphonate and an alkyl benzene sulphonate respectively with tert.-octyl phenol sulphide are similarly treated (II). The products are employed as antioxidants and stabilizers, e.g. in lubricating oils (see Group III) and natural and synthetic rubber and asphalts. Specification 744,534 is referred to.ALSO:A lubricating oil composition comprises a major proportion of a lubricating oil and a minor proportion of an additive obtained by forming a mixture of an oil-soluble hydrocarbon sulphonic acid or an alkaline earth metal salt thereof and an alkyl phenol sulphide or alkyl thiophenol sulphide whose alkaline earth metal salts are oil-soluble or an alkaline earth metal salt thereof, heating this mixture with a basic reacting inorganic alkaline earth metal compound in an amount in excess of that required to form the normal metal salt of the mixture and contacting the product so formed with an acidic reagent in an amount sufficient to neutralize at least a portion of the tetratable basicity of the product (see Group IV(b)). Preferred alkyl phenol sulphide or alkyl thiophenol sulphide starting materials are defined by the formula R Ar (XH) - Sx - R1 and the alkaline earth metal salts thereof. Ar in the formula may be a benzene nucleus or may consist of a plurality of rings, e.g. biphenyl, or maybe a condensed nucleus, e.g. derived from naphthalene or anthracene, R is an alkyl group, X is sulphur or oxygen, x is an integer from 1 to 4 and R1 is an organic group, e.g. an aryl, alkyl, aralkyl or alkylaryl group which may contain substituent atoms or groups such as halogen, nitro, amino, hydroxy, alkoxy, aroxy, mercapto or carboxy. Especially suitable are compounds of the formula R Ar (XH) - Sx - Ar (XH) R where R represents at least one alkyl radical attached to an aromatic nucleus Ar, the number of carbon atoms in all such radicals attached to each benzene nucleus being at least 5 where the metal complex is to be dissolved in hydrocarbon oils, X is oxygen or sulphur and x is an integer from 1 to 4. Nucleus substituents which may be present include alkyl, cycloalkyl, aralkyl, aryl, carboxyl, hydroxyl, alkoxy, aroxy, sulphydryl, nitro, ester (organic or inorganic), keto, amino, aldehyde, chlormethyl, aminomethyl, alkyl thiomethyl, and alkyl xanthomethyl. Alkaline earth metal salts of the above compounds may be employed. The starting materials may be alkyl phenol thioethers, alkyl phenol disulphides or polymers thereof. Lists of the general formulae of suitable alkyl phenol sulphides and alky thiophenol sulphides are furnished. In examples: A mixture of an oil-soluble calcium petroleum sulphonate, tertiary octyl phenol sulphide and mineral oil is heated with an excess of barium hydroxide and part of the product is blown with moist carbon dioxide whilst heating at elevated temperatures; water sensitivity and copper and silver corrosion tests are applied to both the carbon dioxide-treated and the untreated product; a similar product is prepared and compared with a product obtained by heating an alkyl benzene sulphonate and tertiary octyl phenol sulphide with barium hydroxide in mineral oil and treating the reacted mixture with moist carbon dioxide. Other specific acidic reagents mentioned include hydrogen halides, acidic nitrogen oxides and sulphur oxides. Base stocks include mineral oils, hydrogenated oils or white oils, synthetic oils prepared by the polymerization of olefines, e.g. polyisobutylenes, or by the reaction of carbon monoxide with hydrogen, or by the hydrogenation of coal, cracking coal tar fractions, coal tar or shale oil fractions, animal, vegetable or fish oils which may be hydrogenated or voltolized, alone or in admixture with mineral oils, and oils of the ester, polyester and polyester types, e.g. di - 2 - ethylhexyl sebacate, diabasic acid esters and polyalkylene oxides. The additives may also be incorporated in diesel fuels and kerosene. Additional additives which may be incorporated include detergents such as metal soaps, phenates, alcoholates, organophosphates, thiophosphates, phosphites, thiophosphites, salicylates, xanthates, thioxanthates, carbamates, amines and derivatives thereof, sulphurized and phospho-sulphurized metal phenates and metal phenol sulphonates, nickel oleate, barium stearate, calcium phenyl stearate, zinc diisopropyl salicylate, aluminium naphthenate, calcium cetyl phosphate, zinc methylcyclohexyl thiophosphate and calcium dichlorostearate dyes, pour depressors, heat-thickened fatty oils, sulphurized fatty oils, organometallic compounds, metallic or other soaps, sludge dispersers, antioxidants, thickeners, viscosity index improvers, oiliness agents, resins, rubber, voltolized mineral oils and/or waxes, colloidal solids e.g. graphite, zinc oxide, and assisting agents such as esters, ketones, aldehydes, halogenated or nitrated compounds and alcohols, e.g. alcohols having 8 or more, preferably 12 to 20 carbon atoms, which may be saturated branched chain alcohols such as octyl, lauryl, cetyl and stearyl alcohols. Specification 744,534 is referred to.ALSO:An antioxidant or stabilizing agent for asphalt and rubber is obtained by forming a mixture of an oil soluble hydrocarbon sulphonic acid or an alkaline earth metal salt thereof and an alkyl phenol sulphide or alkyl thiophenol sulphide whose alkaline earth metal salts are oil soluble or an alkaline earth metal salt thereof, heating this mixture with a basic reacting inorganic alkaline earth metal compound in an amount in excess of that required to form the normal metal salt of the mixture and contacting the product so formed with an acidic reagent in an amount sufficient to neutralise at least a portion of the titratable basicity of the product (see Group IV(b)). Lists of starting materials are furnished. Specification 744,534 [Group III] is referred to.