Patent GB-776221-A (GB)
Title: Improvements in or relating to lubricating oil composition
IPC: C10M153/00
Filed: 1955-06-28
Abstract: A lubricating composition (see Group III) comprises (a) a phosphosulphurized alkaline earth metal salt of an alkyl phenolsulphide having two or more C4-C24 alkyl groups in the molecule and (b) a zinc dialkyl dithiophosphate having 3-20 carbon atoms in each alkyl group.  The alkaline earth metal salt of an alkyl phenol sulphide, from which ingredient (a) is prepared may have the formula <FORM:0776221/IV(b)/1> wherein R is a C4-C24 alkyl group, preferably a secondary or tertiary alkyl group, M is an alkaline earth metal and x is an integer from 1 to 4, or may be derived from an alkyl phenol disulphide of formula <FORM:0776221/IV(b)/2> The alkyl phenol from which ingredient (a) is derived may be prepared by alkylation of phenol with an olefin, suitable olefins being butylenes, amylenes, olefin polymers (e.g. tripropylene, di- or tri-isobutylene, polymers of n-olefins, copolymers of n- and sec.- or tert.-olefins, copolymers of olefins and diolefins and polymers of petroleum refinery butylene fractions) and petroleum refinery gases containing propylene, butylenes and amylenes.  In the case of alkylation of phenol with di-isobutylene or tripropylene, two molecular equivalents of olefin per equivalent of phenol may be employed, thus producing di-tert.-octyl-phenol or a di-nonyl phenol respectively.  The alkyl phenol is reacted with sulphur dichloride to produce the phenol monosulphide, or with sulphur monochloride to produce the phenol disulphide, small amounts of polysulphides being produced in each case.  The alkyl phenol sulphide may be converted to its salt by reaction with an alkaline earth metal or with an alkaline earth metal oxide, hydroxide, sulphide, alkoxide, hydride or carbide. Alternatively, the alkaline earth metal salt may be prepared from an alkali metal salt by double decomposition. Phosphosulphurization of the alkaline earth metal salt may be effected by reaction with a mixture of phosphorus and sulphur, by reaction with first one element and then the other, or by reaction with a phosphorus sulphide (e.g. P2S5, P4S3 or P4S7 with or without phosphorus and/or sulphur.  The phosphorus may be used either in the white (yellow) or red form.  The alkaline earth metal phenol sulphide may be subjected to heat treatment (e.g. 8-10 hours at 150-180 DEG  C.), or to blowing with dry or moist carbon dioxide, before phosphosulphurization, while the phosphosulphurization may be carried out in the presence of a small proportion of an olefinic material (e.g. tetraisobutylene, cracked wax or an unsaturated alcohol).  Ingredient (a) may be after-treated before use.  Thus, it may be blown with dry or moist air or nitrogen or superheated steam, and/or it may be neutralized with barium or calcium hydroxide or calcium oxide.  In an example, barium tert.-octyl phenol sulphide is heated with P2S5 in mineral oil solution, then blown with nitrogen, filtered and finally air-blown. Ingredient (b) has the formula <FORM:0776221/IV(b)/3> where R is a C3-C20 alkyl group, and may be derived from hexyl, n- or iso-octyl, 2-ethylhexyl, n- or iso-decyl, dodecyl, tetradecyl, or octadecyl alcohol or C8, C10, C13 or C16 oxo alcohol.  The zinc salt may be prepared by reacting the alcohol with P2S5 and then neutralizing with zinc or zinc oxide.  Alternatively, the P2S5-treated alcohol may be neutralized with an alkali metal hydroxide or carbonate, and the alkali metal dithiophosphate thus obtained converted to the zinc salt by double decomposition.ALSO:A lubricating composition, suitable for use as a crankcase lubricant for internal combustion engines, comprises a major proportion of mineral lubricating oil, 0.5-2.5 per cent of a phosphosulphurized alkaline earth metal salt of an alkyl phenol sulphide having two or more C4-C24 alkyl groups in the molecule and 0.2-2.5 per cent of a zinc dialkyl dithiophosphate having 3-20 carbon atoms in each alkyl group, the percentages being based on the weight of the total composition.  The lubricating compositions may also contain about 0.25-1.0 per cent by weight, based on the total composition of an alkaline earth metal sulphonate which may be a petroleum sulphonate, alkylbenzene sulphonate or alkyl naphthalene sulphonate.  Other ingredients which may be present in the lubricating composition are dyes, pour depressors, heat-thickened fatty oils, sulphurized fatty oils, organo metallic compounds, metallic or other soaps, sludge dispersers, antioxidants, thickeners, viscosity index improvers, oiliness agents, resins, rubber, olefin polymers, voltolized fatty oils or fats, voltolized mineral oils and/or voltolized waxes, colloidal solids (e.g. graphite or zinc oxide), solvents and assisting agents (e.g. esters, ketones, alcohols, aldehydes, and halogenated or nitrated compounds).  In the examples, lubricating compositions are described consisting of mineral lubricating oil, polyisobutylene, and polymerized C8 - C12 alcohol esters of methacrylic acid together with (a) zinc diisohexyl dithiophosphate and (b) a blend of phosphosulphurized barium tert. - octyl phenol sulphide and calcium petroleum sulphonates.  For comparison purposes similar lubricating compositions are described in which ingredient (a) or (b) has been omitted, or in which ingredient (b) or ingredients (a) + (b) are replaced by (c) a blend of barium tert. - octyl phenol sulphide and calcium petroleum sulphonates or (d) a blend of calcium and barium tert. - octyl phenol sulphides, calcium petroleum sulphonates and P2S5 -treated terpene.