GB407379A - A process for improving the temperature-viscosity curves of lubricating oils - Google Patents

Abstract

Oily to solid polymerization or condensation products of m.w.500--10,000, S.G. about 0.86, viscosity 3--150 DEG Engler at 99 DEG C., viscosity index 120--150, and containing 16.0--16.3 parts of hydrogen per 100 parts of carbon, are obtained by treating paraffin waxy hydrocarbons and/or substances containing substantial amounts of such hydrocarbons with silent and preferably high frequency electric discharges, and removing unchanged wax and products of middle oil character from the products. The voltolization is carried out in known apparatus such as (1) Siemen's ozone tubes in which the foam produced is reconverted into the coherent liquid state and returned to the treatment zone; or (2) multiple alternating electrode and dielectric sheets over which thin layers of the material treated are caused to flow by pumps, scoops or sprayers, or by rotating the partially immersed sheets. Alternating currents of 4000--8000 volts and 50--50,000 or more cycles, and reduced pressures of 0.1--1.0 to 5--10 cm. of mercury may be used for as long as 100 hours. There may be present: (1) Gases or vapours, e.g. hydrogen, nitrogen, carbon monoxide, carbon dioxide, halogens, hydrogen halides, saturated or unsaturated gaseous hydrocarbons, coke-oven gas, natural gas, waste gases from destructive-hydrogenation processes, benzine vapours; these gases and vapours help to form foam and promote the condensation. (2) Foam-forming agents, e.g. saponine, sulphonic acids and their salts, oleic or other fatty acid of high m.w. (3) Substances promoting condensation, e.g. active carbon, active silica, Florida earth, metal powders, e.g. molybdenum, tungsten, vanadium, copper; oxides of zinc, cadmium, molybdenum, tungsten, chromium, vanadium, copper, or of other metal; iodides or other halogen compounds of sulphur, phosphorus, boron, copper, silver, magnesium, titanium, vanadium, molybdenum, tungsten, chromium nickel, cobalt, or other metal; organic halogen compounds, e.g. of benzene, toluene, xylene, naphthalene, and methyl, ethyl, methylene, or ethylene iodide, bromide, or chloride; or condensing agents such as aluminium chloride, zinc chloride or boron fluoride. (4) Solvents and diluents, e.g. di- or tetra-chlorethane, tetrachlorbenzene, aniline, hard or soft paraffin wax, paraffin oil, illuminating oil, aromatic hydrocarbons, e.g. naphthalene, tetra- or decahydronaphthalene, anthracene, phenanthrene; condensation or polymerization products of low m.w. unsaturated hydrocarbons; products obtained by condensing halogenated paraffin wax with naphthalene in presence of aluminium chloride. Where the diluent may polymerize or condense it is preferably not added until the last third of the treatment. The initial waxy materials are preferably paraffin wax hydrocarbons of m.w. above 330 or better over 350, or derivatives thereof, e.g. ceresine, ozokerite, neftgil, hatchettine, montan wax, mixed or not with paraffin wax or with hydrocarbon oils containing more than 13 or 14.5 parts of hydrogen per 100 parts of carbon, e.g. petrolatum, crude paraffin wax, petroleum jelly, crude lubricating oils containing paraffin wax, paraffin oil, spindle oil, machine oil, tar oil, cylinder oil, hydrogenated naphthalenes, montan wax, aromatic oils, high boiling oils from destructive hydrogenation. They may be prepared synthetically, e.g. by the electrolytic treatment of fatty acids, or by a destructive hydrogenation of waxy hydrocarbons followed by condensation in presence of aluminium chloride or like condensing agent, or by condensing halogenated paraffin wax with naphthalene in presence of aluminium chloride, or by polymerizing olefines or other unsaturated hydrocarbons of low m.w., or by treating low m.w. hydrocarbons with high frequency electric currents. They may be obtained by distillation from petroleum, extraction from brown coal, or by destructive hydrogenation. They may be improved by preliminary treatment consisting of one or more of the following, usually to remove the lower m.w. hydrocarbons and/or asphaltic and/or resinous impurities:--(1) Fractional distillation, advantageously with steam, hydrogen, nitrogen, carbon-dioxide, or benzine vapour. (2) Hydrogenation at elevated temperature and preferably pressure by hydrogen or gases containing it, usually in the presence of catalysts and so that little splitting occurs. The hydrogen content is raised and the colour improved. (3) Extraction with solvents to separate fractions rich in hydrogen from those poor, including asphaltic and resinous matters. Solvents specified are liquefied ethane and/or propane, liquefied sulphur dioxide, phenol, aniline, nitrobenzene, furfurol, ketones, ketonic acids, and mixtures of cyclohexane with methanol. (4) Treatment with refining agents, e.g. sulphuric acid, bleaching earths, boron fluoride, chromic acid. (5) Fractional precipitation from a solution, e.g. dissolving in ether, chloroform, or chlorinated ethylene, and precipitating by adding acetone or alcohol, with or without cooling. (6) Fractional crystallization by cooling a solution in stages. (7) Strongly cooling a solution, e.g. to -40 DEG C., and fractionally sweating the precipitate; or by direct fractional sweating if the initial material be sufficiently pure. (8) Mildly cracking, advantageously in presence of hydrogen under pressure and of dehydrogenating catalysts, and then cooling, maybe fractionally, to 10 DEG C. or even to - 40 DEG C. the product or its solution, and centrifuging or filtering. (9) Petrolatum and similar products may be mixed with light benzine, cooled to low temperatures, e.g. - 25 DEG C., and filtered or centrifuged, if desired in stages, to obtain high quality solid paraffin wax; the wax may then be freed from gums or asphalts as by distillation in vacuo up to 400 DEG C. while employing scavenging gases. The unchanged wax and middle oil-like substances are separated from the crude voltolized product by one or more of the following methods:--(1) Distillation up to 280 DEG C., preferably under reduced pressure and with water or benzine vapours, or hydrogen, nitrogen, carbon dioxide, coke oven gases, or waste gases from destructive hydrogenation. Bleaching or Florida earth or other adsorbent may be present. (2) Extraction, preferably by liquefied gaseous hydrocarbons, e.g. methane, ethane, propane, butane, ethylene, propylene, or mixtures thereof. (3) Dissolving the crude product in e.g. gasoline, kerosene, benzine, trichlorethane or other halogenated hydrocarbon, cooling to between - 8 and - 30 C., filtering or centrifuging to remove the precipitated wax, and then distilling off the solvent and the lower boiling voltolization products. (4) Dissolving the crude product, e.g. in kerosene, trichlorethane, or ether, and precipitating out the pure product, maybe in stages, as by acetone or alcohol. The wax may be precipitated afterwards from the solution by lowering the temperature. The crude product may also be purified and the iodine no. reduced, before or after the removal of unchanged wax, by catalytic hydrogenation without splitting, e.g. by treatment with hydrogen at 100--450 C. at 20--1000 atmos. pressure in presence of nickel or cobalt and maybe of a diluent. Distillation, or solution and precipitation, may follow. In all cases the purified and/or wax-free product may be treated with Florida earth or other adsorbent; and it may be submitted to condensation in presence of aluminium chloride or similar condensing agent whereby the viscosity is increased, e.g. from 25--30 DEG to 100 DEG Engler at 99 DEG C. The products mixed or not with water or with pour point depressants, e.g. the product of halogenated paraffin wax condensed with naphthalene in presence of aluminium chloride, are used as lubricants. They are also used as additions:--to hydrocarbon oils for coating protecting, or impregnating, especially tar oils containing paraffin wax or products obtained by extracting tars with alcohol or other solvent; to hydrocarbon oils containing naphthalene, anthracene, carbazole, or other cyclic hydrocarbons to prevent crystallizing out at low temperatures; to mineral oils, tars, and extraction and destructive-hydrogenation products to facilitate the separation therefrom of paraffin wax by chilling processes; to paraffin wax to increase the viscosity of the melt and to prevent cracks and white crystal centres and so render the wax suitable for candles; to benzine, gas oil, illuminating oil, and other liquid hydrocarbons to increase viscosity, facilitate pumping, and reduce consumption; to motor fuels to lubricate the valves and seal the piston rings; to paraffinum liquidum or other white oil for pharmaceutical or cosmetic purposes, preferably after stirring with water or after purification; and alone or mixed with lubricating oils of high viscosity index to lubricants to improve the viscosity, viscosity index, pour point, and colour, and impart fluorescence. There may also be added to the lubricants:--metal soaps, e.g. lead, sodium, ammonium, oleates or stearates; condensation products of high m.w. organic acids; oxidized oil distillates of high B.P.; paraffin wax; pour-point depressants; hydrocarbons of m.w. above 1000 or 2000, e.g. hydrogenated rubber or balata or guttapercha, hydrogenated oxygen-free resins soluble in oil, hydrogenated polymerization products of butadiene or other diolefine, cyclocaoutchouc, polymerized styrene or indene, hydrogenated polymerized styrene, oil-soluble polymerization products of isobutylene or other olefine; and oil-soluble cellulose derivatives, e.g. cellulose laurate, and their hydrogenated products. In examples:--(1) Ceresin M.P. 73 DEG C. is treated at 80--100 DEG C. in a Siemen's ozone tube at 5--10 m.m. with discharges of 7000 volts and 1000 cycles for 25--30 hours, an equal weight of paraffin wax M.P. 50 DEG C. being added after 20--22 p hours; the product