Patent GB-776438-A (GB)
Title: Improvements in or relating to lubricant additives having detergent and dispersant properties
Filed: 1953-07-31
Abstract: Oxidized hydrocarbons for use as detergents in lubricating oils are prepared by oxidation of a substantially saturated hydrocarbon polymer having a ratio of carbon atoms to olefinic bonds of not less than 16:1, a refractive index M20D of between 1.440 and 1.520, a viscosity of at least 50 S.U.S. at 210 DEG  F., a viscosity index when determinable of at least 50, an average carbon content of at least 40 and an average molecular weight of at least 550, not more than a minor portion thereof having a molecular weight below 450, by means of oxygen or an oxygen-containing material capable of releasing free oxygen under the oxidizing conditions of the reaction, the oxidation being carried out at a temperature from -40 DEG  to 800 DEG F. and at pressures from subto super-atmospheric, the temperature and pressure being adjusted according to the selected oxidizing agent (see Group IV (b)).  Suitable hydrocarbon polymers include substantially saturated dienic and C2 to C12 olefinic polymers, such as those from ethylene, propylene, isobutylene, butadiene and pentadiene, alkylated polystyrenes and styreneolefinic copolymers and especially a liquid or solid polybutadiene produced either with sodium catalyst or by emulsion polymerization and coagulation, the product being hydrogenated and then thermally depolymerized or a propylene polymer obtained by polymerization using a ZrCl4 or chromia-silica-alumina catalyst (see Examples XVII to XIX).  The oxidation may be effected with oxygen alone or in admixture with nitrogen, CO2, natural gas or methane, or with SO3, NO2, N2O3, N2O5, acidified chromium oxides and chromates, permanganates and peroxides, e.g. ozone, hydrogen peroxide and sodium peroxide.ALSO:Oxidized hydrocarbons for use as detergents in lubricating oils (see Group III) are prepared by oxidation of a substantially saturated hydrocarbon material having a ratio of carbon atoms to olefinic bonds of not less than 16 : 1, a refractive index M20D of between 1.440 and 1.520, a viscosity of at least 50 S.U.S. at 210 DEG  F., a viscosity index when determinable of at least 50, an average carbon content of at least 40 and an average molecular weight of at least 550, not more than a minor portion thereof having a molecular weight below 450, by means of oxygen or an oxygen-containing material capable of releasing free oxygen under the oxidizing conditions of the reaction, the oxidation being carried out at a temperature from -40 DEG  to 800 DEG F. and at pressures from subto super-atmospheric, the temperature and pressure being adjusted according to the selected oxidizing agent (see also Group IV (a)).  Suitable hydrocarbon starting materials include substantially saturated dienic and C2 to C12 olefinic polymers, such as polymers from ethylene, propylene, isobutylene, butadiene and pentadiene, alkylated polystyrenes and styrene-olefinic copolymers; and petroleum lubricating oils substantially free from aromatics and asphalt and preferably de-waxed.  Thus, the hydrocarbon materials may comprise a liquid or solid polybutadiene produced by emulsion polymerization and coagulation, which is hydrogenated and then thermally depolymerized; a propylene polymer obtained by polymerization using a ZrCl4 or chromia-silica-alumina catalyst; and hydrocarbon oils from a variety of crudes which are topped, then fractionated with liquid propane which may contain methane, ethane or butane, in one or more stages, the overhead portion being solvent-extracted for reduction of the aromatic content and dewaxed; this feed stock may be further refined by hydrogenation or by means of a selective adsorbent for aromatics, e.g. by passing the feed through a silica gel at 40-170 DEG  F. and collecting the effluent and that fraction which is obtained by desorbing the gel with pentane or other liquid saturated aliphatic hydrocarbon.  The oxidation may be effected with oxygen alone or in admixture with nitrogen, CO2, natural gas or methane or with SO3, NO2, N2O3, N2O5, acidifie chromium oxides and chromates, permanganates and peroxides, e.g. ozone, hydrogen peroxide and sodium peroxide. Air and like less active oxidizing agents are suitably used for 3 to 75 hours at 100-800 DEG  F. under 10-200 p.s.i.a. pressure, if desired in the presence of oxidation catalysts, including various metal soaps and reaction products of terpenes with phosphorus-sulphur containing compounds, e.g. P2S5, or oxidation inhibitors such as C16-C24 branched chain or normal aliphatic alcohols for better control of reaction time. More active oxidizing agents, e.g. SO3, may be used at -40 DEG  to 400 DEG  F.  Liquid SO3 is used with a diluent, including liquid sulphur dioxide, hexane, tetrachlorethylene, pyridine, nitrobenzene or dioxane; gaseous SO3 may be used alone or with a carrier gas.  The weight ratio of hydrocarbon oil to SO3 is normally between 3 : 1 to 18 : 1.  The oxidation causes a scission of the large hydrocarbon molecules with a concomitant condensation reaction resulting in increase in the viscosity of the reaction mixture.  The oxidation is suitably effected for a time sufficient to increase the viscosity of the reaction mixture determined in the absence of reaction diluent at 210 DEG  F., from 0.5 to 50 fold above that of the unoxidized hydrocarbon feed stock.  The extent of the oxidation may also be determined by measuring the amount of water or propane-insoluble oxidized hydrocarbon material produced or the detergent activity of the reaction mixture.  The oxidation reaction mixture comprises the active detergent product dissolved in unchanged hydrocarbon oil and may be used as such as a lubricating oil additive.  Alternatively, the active ingredient may be isolated by selective extraction of the unchanged oil with, for example, phenol, dioxane, morpholine, propane alone or admixed with other low boiling hydrocarbons, isopropanol, tert.-butanol, methyl ethyl ketone, ethyl acetate and dimethyl formamide, and generally C3 to C8 organic polar solvents.  Preferably, the reaction mixture is extracted with propane at 50 DEG  to 250 DEG  F. under 200 to 500 p.s.i.g. pressure and may then be further extracted with a C3 to C8 polar solvent.  The product obtained by oxidation with SO3 may be subjected to catalytic hydrogenation or chemical reduction to improve the colour.  The isolated detergent product is a solid material soluble in pentane, benzene, diethyl ether and lubricating oils of the petroleum, polymer, and diester types, and has an acid number below about 50, a saponification number between 0 and about 100 and an oxygen content of about 1 to 15 per cent; it may comprise alcohols, esters, ethers, lactones, anhydrides, ketones and aldehydes.  The solid detergent products are preferably used in lubricating oils in amounts of 0.1 to 10 per cent by weight of the composition; other additives of the usual types may also be present.  The propane-soluble components of the oxidation product may be used as viscosity index improvers.  In typical examples: (1) a refined mid-continent oil of viscosity 203 S.U.S. at 210 DEG  F. and a V.I. of 93 is air-blown at 250 DEG  C. until the viscosity reaches 625 S.U.S. at 210 DEG  F., whereupon the mixture is extracted with propane yielding the desired propane-insoluble detergent, a portion of which is further extracted with isopropanol; lubricating oil compositions are prepared from the total oxidized mixture, the propane-insoluble material before and after the alcohol extraction, and the propane soluble component using a S.A.E. 30 base oil containing a minor amount of zinc dithio-phosphate or a terpene-P2S5 reaction product and their detensive powers are compared; (5) the same oil is similarly oxidized and propane-fractionated and the propane-soluble component is re-oxidized and then propane-fractionated; (12) a S.A.E. 250 bright stock is oxidized in the same manner as (1) and propane-fractionated; the oxidized-oil and the propane-soluble oxidized oil are each added to S.A.E. 30 base oil containing antioxidant; (13) S.A.E. 250 mid-continental oil is treated with silica gel and air-blown at 400-480 DEG  F. and the product worked up as in (1); (14) the refined oil of (1) is reacted with SO3 in ethylene dichloride at 61-99 DEG F. and then subjected to water, alcohol and dimethyl formamide-alcohol washes, neutralized with guanidine carbonate or ammonia, dissolved in hot methyl isobutyl ketone, filtered and then stripped of solvent; the purified product is tested as a detergent in a lubricating oil containing a terpene-P2S5 reaction product additive; (16) the oil of (1) is oxidized as in (14), extracted with propane, neutralized with NH3, dissolved in benzene, filtered and then stripped and the product containing nitrogen and sulphur is tested as in (14); (17) liquid polybutadiene, obtained by polymerization of the diene with a sodium catalyst, is hydrogenated using a nickel-kieselguhr catalyst and methyl cyclohexane as diluent and the product of M.W. 1030 is oxidized as in (1), extracted with acetone and the resulting detergent tested as in (14).ALSO:Lubricating oil compositions comprise, as detergents, oxidized hydrocarbons prepared by oxidation of a substantially saturated hydrocarbon material having a ratio of carbon atoms to olefinic bonds of not less than 16 : 1, a refractive index n 20/D of between 1.440 and 1.520, a viscosity of at least 50 S.U.S. at 210 DEG F., a viscosity index when determinable of at least 50, an average carbon content of at least 40 atoms per molecule and an average molecular weight of at least 550, not more than a minor portion thereof having a molecular weight below 450, by means of oxygen or an oxygen-containing material capable of releasing free oxygen under the oxidizing conditions of the reaction, the oxidation being carried out at a temperature from -40 DEG  to 800 DEG F. and at pressures from sub-to super-atmospheric, the temperature and