GB700303A - Improvements in or relating to the preparation of hydrocarbon lubricating oil antioxidants and anticorrosion agents and to hydrocarbon lubricating oil compositions containing the same - Google Patents

Abstract

A hydrocarbon lubricating oil antioxidant and anti-corrosion agent is obtained by effecting simultaneous reaction at elevated temperature of a bicyclic terpene, phosphorus pentasulphide, and sulphur, the reactants being employed in the proportion of at least about 4 mols. of the bicyclic terpene and from about 0.5 to about 3 mols. of sulphur for each mol. of phosphorus pentasulphide. Specified bicyclic terpenes are alpha pinene, beta-pinene, camphene, bornylene, a -fenchene, thujene, sabinene and D 3-carene. Commercial grades of turpentine may also be used. A small excess of terpene may be employed, e.g. 6 mols. of terpene per mol. of phosphorus pentasulphide, so as to provide sufficient liquid vehicle to permit easy handling of the reaction product. Any common inert organic solvent can also be used as the liquid vehicle. The reaction temperature should preferably be below 160 DEG C. and is generally from 80 DEG to 90 DEG C. but when reflux equipment is used superatmospheric pressure and more elevated temperatures may be employed. In examples: (1) 0.5 mol. of P2S5 and 1 mol. of sulphur are added to 3 mols. of alpha-pinene and the mixture heated, a SAE 10 grade hydrocarbon lubricating oil and a diatomaceous earth filter aid are then added and the excess terpene stripped off, the oil concentrate is then filtered and an additional amount of the hydrocarbon lubricating oil added to yield a 50 per cent. concentrate of the product in oil; (2) as in (1) except that 0.25 mol. of sulphur is employed, the reaction product being diluted with light grade refined mineral lubricating oil to form a 50 per cent. concentrate; (3) as in (1) using 1.5 mol. of sulphur the reaction product being diluted with hydrocarbon lubricating oil to form a 50 per cent. concentrate; (4) alphapinene, P2S5 and sulphur are reacted as in (1) using various molar proportions of the reactants within the specified range and the products treated as in (1) to yield a 50 per cent. concentrate in lubricating oil; (5) camphene, P2S5 and sulphur are reacted and the product prepared as a 50 per cent. concentrate in oil as in (1); (6) beta-pinene, P2S5 and sulphur are reacted and a 50 per cent. concentrate in oil formed as in (1); (7) steam-distilled turpentine is reacted with P2S5 and sulphur and a 50 per cent. concentrate of the product in oil formed as in (1).ALSO:A hydrocarbon lubricating oil composition comprises a hydrocarbon lubricating oil having dissolved therein a minor proportion by weight of an antioxidant and anticorrosive agent obtained by simultaneously reacting at elevated temperature a bicyclic terpene, phosphorus pentasulphide and sulphur, the reactants being employed in the proportion of at least about 4 mols of the bicyclic terpene and from about 0.5 to about 3 mols of sulphur for each mol of phosphorus pentasulphide (see Group IV (b)). Specified terpenes are alpha-pinene, beta-pinene, camphene, bornylene, a -fenchene, thujene, sabinene and D 3-carene. Commercial grades of turpentine may also be used. A small excess of terpene may be employed, e.g. 6 mols of terpene per mol of phosphorus pentasulphide, so as to provide sufficient liquid vehicle to permit easy handling of the reaction product. Any common organic solvent can also be used as the liquid vehicle. Ordinarily about 0.5 per cent. to 1.25 per cent. of the additive, by weight, is added to the lubricating oil. The additive may be used alone or in conjunction with other hydrocarbon lubricating oil antioxidants or detergents, e.g. the antioxidants comprising the metal salts of esters of dithiophosphoric acids such as barium dioctyl dithiophosphate, zinc dihexyl dithiophosphate and barium didodecyl dithiophosphate. Suitable detergents include the metal salts of petroleum sulphonic acids such as calcium petroleum sulphonate, alkylated aromatic sulphonates such as calcium or barium dodecyl phenyl sulphonate, and metal salts of phenol sulphides and disulphides such as calcium, barium and zinc salts of dioctyl phenol sulphide, diamyl phenol sulphide, and barium and calcium meta-, ortho-, and paraoctyl phenol sulphides. In examples the antioxidant properties of a product obtained by reacting alpha-pinene, P2 S5 and sulphur are demonstrated by submitting a Mid-Continent base lubricating oil of SAE 30 grade containing 0.4 per cent. by weight of the product with or without 0.04 per cent. of iron naphthenate to the Underwood corrosion test using cadmium-silver alloy bearings as test material. Samples obtained by incorporating amounts of 0.75 per cent. to 1.0 per cent. by weight of additives, obtained by reacting alpha-pinene with various proportions of P2 S5 and sulphur within the specified range, in a Mid-Continent base lubricating oil of SAE grade 30, are also subjected to actual operating conditions in a Chevrolet automobile engine for a continuous run of 36 hours and results showing the bearing corrosion, viscosity increase and Neutralization Number are tabulated, a detergent consisting of a barium salt of an alkylated phenol sulphide being included in some of the samples tested. Bearing corrosion tests for a Mid-Continent base SAE 30 grade lubricating oil containing products obtained by reacting camphene, beta-pinene and steam-distilled turpentine respectively with P2S5 and sulphur are also described.