US2465902A - Stabilized liquid petroleum hydrocarbon - Google Patents

Description

Patented 29, 194? STABILIZED LIQUID PETROLEUM HYDROCARBON John G. McNab, Rogers, Summ Cranford, and Dilworth '1. it, N. J assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application June 9, 1945, Serial No. 598,640

11 Claims. (01. zsz-sa'z) This invention relates to stabilized liquid pee troleum products, especially against the deteriorating efiect of oxygen, and it relates more particularly to lubricating oil compositions for use as crankcase lubricants for internal combustion engines, improved as to stability and other properties by the addition of stabilizing agent of the present invention.

The new class of stabilizing agents not only v have the property of inhibiting oxidation and other deteriorating tendencies in petroleum products, but when they are incorporated in mineral lubricating oils they have the additional advantage of imparting detergent properties to such oils, promoting general engine cleanliness when they are used as crankcase lubricants'for internal combustion engines, also improving film strength, and reducing ring sticking, piston skirt varnish formation and the like. These agents are likewise free from the corroding tendencies which have been observed when such well-known addition agents as metal derivatives of fatty acids, naphthenic acids, sulfonic acids, alcohols, phenols and the like have been used.

The new class of products which have now been found to be highly satisfactory as stabilizing agents for petroleum products are the products obtained by the reaction of the elements sulfur and phosphorus with metal salts of sulfonated phenols having at least one alkyl group to impart oil solubility. The elements sulfur and phosphorus are introduced either by reacting these elements in elementary form, either separatelyor in succession, or by the use of a sulfide of phosphorus. The metal salts which may be used are those in which the hydrogen of both the hydroxy and sulfo groups is replaced by a metal. The reaction for the preparation of the additives may generally be brought about in a solution of lubricating oil or other petroleum oil, whereby concentrates may be prepared which may be conveniently stored or shipped and added to the lubrieating oil or other petroleum oil when required.

The exact structure of the compounds obtained by the reaction of phosphorus and sulfur with metal phenol sulfonates is not fully understood, but it is possible that compounds are formed in which the sulfur and phosphorusatoms are attached directly to the metal atoms.

The metal which is present in the salt which is sirable.

reacted with sulfur and phosphorus in accordance with the present invention may be any metal, but a highly preferred group of salts are those containing divalent metals of group II of the periodic table, especially the alkaline ear h metal salts, that is, those of calcium, barium, strontium and magnesium. The salts of zinc, aluminum, tin, cobalt and nickel are also particularly de- Broadly stated, the new class of additives used for stabilizing petroleum oil products in accordance with the present invention may be defined as the products obtained by reaction of the elements sulfur and phosphorus with an oil-soluble metal salt of a compound of the formula where Ar is an aromatic nucleus, R is an alkyl group, and m, n and p are integers, in which the hydrogen of all of the -OH and SOsH groups is replaced by metals. The aromatic nucleus of the compound may be a single ring nucleus such as the benzene nucleus, or a double ring structure, such is biphenyl, or it may be a condensed nucleus, such as the naphthalene nucleus, or other similar structure. The alkyl radical or radicals may be short or long, straight chain or branched, provided only that the hydrocarbon chain or chains are of sufllcient length to impart the necessary oil solubility. Long straight chain groups derived from petroleum waxes may be used, and for certain purposes long branched chain groups are preferred. It is intended that the above formula include aromatic groups in which other substituents than those specified may also be present, such as aralkyl, carboxyl, hydroxyl, alkoxy, aroxy, mercapto, nitro, ester, keto, amino, aldehydo, chloromethyl, aminomethyl, and similar groups, as well as halogen atoms, etc. Diflerent types of atoms or groups may be attached to the same aromatic nucleus, and metal atoms may be substituted for hydrogen atoms in the hydroxyl, carboxyl or like groups.

' The metal phenol sulfonate salts which are employed in the present invention are of the type in which both the sulfonic acid hydrogen and the hydroxyl hydrogen have been replaced by metal. which the sulfonic acid hydrogen has been replaced by one metal, such as zinc, and the hy- Mixed metal salts may also be used in p droxyl hydrogen by a different metal, such as barium. These types of salts are illustrated by the formulas below, examples being given of both alkyl phenol sulfonates and of alkyl phenol sulfide sulfonates:

Among the more preferred starting materials in the preparation of the preferred addition agents are phenol, cresol, tert.-butyl phenol, tertoctyl phenol, petroleum phenols, naphthols, and the like. Beside the phenols themselves, another preferred group of related materials are the alkylated phenol sulfides and thiophenol sulfides.

The following aretypical representatives of metal salts of phenol sulfonic acids which may be reacted with sulfur and phosphorus to produce useful additives for petroleum oils in accordance with the present invention:

Mixed barium-zinc salt of wax alkylated phenol sulfonic acid Tin double salt of cetyl Barium double salt of isododecyl phenol sulfide sulfonic acid Phenol sulfonic acids to be used in the present invention may be prepared by reacting a phenol, naphthol, phenol sulfide, or the like with. an olefin or olefin polymer in a hydrocarbon oil solution, while gradually adding sulfuric acid under controlled temperature conditions. In this method of preparationthe sulfuric acid serves both as an alkylation catalyst and as a sulfonating agent. An alternative procedure is first to alkylate the phenol in the presence of a different catalyst and then sulfonate the alkylated phenol with sulfuric acid. Thus, phenol can be alkylated with diisobutylene (the dimer of isobutylene) in the presence of stannic ride,- or with a mixed butene polymer of 16 to 20 carbon atoms, using an AlCla-HCl catalyst. The alkyl phenol is then sulfonated as described above.

The method usually most convenient for preparing polyvalent metal sulfonates is that of converting a sodium sulfonate by double decomposition. For example, a calcium alkyl phenol sulfonate may be prepared by reacting an isopropyl alcohol solution of calcium chloride with an alcoholic-naphtha solution of sodium alkyl phenol sulfonate.

In addition to the normal metal salts of phenol sulfonic acids it is also contemplated to employ in the present invention basic salts of polyvalent cresol sulfonic acid metals in which at least one hydroxyl group is attached to the metal atom. It is also contemplated to employ the so-called complexes or coordination compounds which metal sulfonates form with other metal salts, particularly inorganic salts, under certain reaction conditions. To prepare these coordination compounds an oil solution of a metal alkyl phenol sulfonate'may be emulsified with an aqueous solution of an inorganic salt such as calcium chloride and then heated to remove water. The resulting complex is oil-soluble and remains in solution when the product is filaceaeoa tered to remove any excess inorganic salt over that required to form the complex, Examples of complexes which may be prepared by this procedure include:

Calcium double salt of cetyl phenol sulfonic acid-calcium chloride complex Barium double salt of isohexadecyl phenol sulfonic acid-Stannic chloride complex Zinc double salt of lauryl phenol sulfonic acidzinc nitrate complex Calcium double salt of octadecyl phenol sulfonic acid calcium chloride calcium hydroxide complex In accordance with the present invention, the metallic salt of a phenol sulfonic acid or related compound is caused to react with the elements sulfur and phosphorus. This may be accomplished by adding a mixture of the substances in elemental form, or first one element and then the other, to the heated metallic compound, or by adding a sulfide of phosphorus, such as Pass,

P483, P431, etc., or the like, or by treating with both sulfur and/or phosphorus and a sulfide of phosphorus, or by treating with any other substances containing ssentially only the elements sulfur and phosphorus. The phosphorus may be used either in the white (yellow) or red allotropic form, and sulfur may likewise be used. in any of its allotropic forms.

It is ordinarily most convenient to use a sulfide of phosphorus. In carrying out the reactions described above the proportions of phosphorus sulfide and metal salt of phenol sulfonic acid are so chosen that from 0.05 to 2 atoms of phosphorus are reacted with 1 atom of polyvalent metal, the preferred ratio being within the limits of about 0.2 to 1.2 atoms of phosphorus per atom of metal.

Although the reaction can be brought about by fusing the metal phenol sulfonate with phosphorus and sulfur, or with a phosphorus sulfide, it is more convenient to carry out the reaction with the aid of a solvent, preferably a high boiling hydrocarbon solvent, such as xylol or a pe- After the reaction is complete, the product is filtered and the solvent. is removed by evaporation. The completion of the reaction may be determined by immersing a copper strip into the solution, the failure to form a dark stain within a few seconds being an indication of completion. A particularly preferred reaction medium is a lubrieating oil fraction, since the final reaction products can thus be obtained as a mineral oil concentrate of the desired additive, which may be conveniently shipped or stored as such and then readily blended with a lubricating oil base stock inthe desired concentration to form a finished lubricating oil blend.

Generally the additives of the present invention are most advantageously blended with lubrieating oil base stocks in concentrations between the approximate limits of 0.02% and 5% and preferably from 0.1% to 2.0%, although larger amounts may be used for some purposes. The exact amount of addition agent required for maximum improvement depends to a certain extent on the particular products used, the nature of the lubricating oil base stock and the general operation conditions of the engine in which the lubricating oil is to be employed. This same general range of concentration will also be effective when the additives are to be used in greases Memo:

the latter instance greater amounts may also be I employed, e. g., up to It is often convenient to prepare concentrates of the additives in oil, containing, say, 25 to 75% of the effective addition agent, the concentrate later being added to a suitable lubricating oil base stock to give a finished blend containing the desired percentage of additive. Thus, when using a 40% concentrate, 2.5% of this material may be blended with a suitable base stock to give a finished oil containing 1% of effective addition agent.

In the following examples are described the steps in the preparation of a product in accordance with the present invention and the results obtained on testing the same in a lubricating oil blend. It is to be understood that these examples are given for illustrative purposes only and are not to be construed as limiting the scope of the invention in any way.

EXAMPLE 1 I Preparation of alkylated phenol Branched chain C1eC2o alkyl phenol was prepared in the following manner, using boron fluoride catalyst. 1340 grams of BFa was injected into 13.2 kg. of phenol which was placed in a glass lined reactor. During a two-hour period 31.4 kg. of butene polymers of 400-600 F. boiling range (obtained from naphtha rerun tower bottoms) was added, the temperature being held at 115 F. maximum during this period and allowed to rise tov 120 F. for an additional 4 hour period. the total reaction time being 6 hours. The reaction mixture was then washed 5 times with hot water 170-185 F), 12 liters of water being used each time. The crude product was then steamdistilled up to 400 F. bottoms temperature, the desired alkylated phenols being obtained in 30.7 kg.

- yield as the bottoms from this distillation. An-

alysis of the distillate and of the water from the above washing step indicated that 77% of the phenol and 76% of the butene polymer had reacted.

EXAMPLE 2 Sulfonatz'on of alkylated phenol and conversion to calcium salts (a) 996 grams of alkylated phenol from Example 1 was dissolved in 640 grams of petroleum naphtha (boiling range 160 to 240 F.) and placed in a reaction flask. Then over a period of 2 hours 462 grams of sulfuric acid was added dropwise with stirring; the temperature being maintained at 25 to 35 C. The mixture was stirred for an additional 7 hour period and then allowed to settle overnight. The acid layer was withdrawn and centrifuged. The top layer from this step (volume 52 cc.) was recharged to the reaction mixture along with an additional 36 grams of petroleum naphtha. Then an additional 158 grams of sulfuric acid was added dropwise and stirring was continued for another 8-hour period. After the mixture had been allowed to settle, the acid layer was withdrawn and centrifuged and the top layer of this step again added to the naphtha solution of phenol sulfonic acids.

(b) A solution of sodium methoxide was prepared by adding 93 grams of sodium to 1 liter of methanol. This solution was slowly added to 1116 grams or the naphtha solution of alkylated phenol sulfonic acids from part (a), the addition taking /2 hour. The mixture was stirred for an additional 3-hour period and was then cooled to 80 F. To this was then added-a so lution of 225 grams of calcium chloride in 2 liters of isopropyl alcohol. There was no appreciable change in temperature. This mixture was then stirred for 2 hours and finally filtered. The filter residue was washed several times with isopropyl alcohol, giving a total filtrate volume of approximately 9 liters. The solvent Was removed from the filtrate by evaporation, leaving 550 grams of powdery residue. This residue was redissolved in petroleum naphtha and the solution filtered 'andthe solvent removed from the filtrate by evaporation, giving a final yield of 440 gram of the di-calcium salt of the high molecular weight alkyl phenol sulfonic acids. Analysis of the product: C=59.89%, H=8.72%, S=5.88%, Ca=8.54%.

EXAMPLE 3 Treatment of calcium salt of alkyl phenol suljonate with phosphorus pentasulflde and filtered and the solvent removed by evaporation and the residue then pulverized. Analysis of the product: Ca=8.10%, P=3.14%, S=8.91%.

EXAMPLE 4 Corrosion test Blends of the additives prepared in Examples 2 and 3 were made in an extracted Coastal oil of 60 seconds Saybolt viscosity at 210 F. in 1% concentration and submitted to a 16 hour corrosion test conducted as follows:

500 cc. of the oil to be tested was placed in a glass oxidation tube (13" long and 2% diam eter) fitted at the bottom with a A" bore air inlet tube perforated to facilitate air distribution. The oxidation tube was then immersed in a heated bath so that the oil temperature was maintained at 325 F. during the test. Two quarter sections of automotive bearings of copperlead alloy of known weight having a total area of 25 sq. cm. were attached to opposite sides of a stainless steel rod which was then immersed in the oil and rotated at 600 R. P. M., thus providing sufiicient agitation of the sample during the test. Air was then blown through the oil at the rate of 2 cu. ft. per hour. The hearings were washed and weighed at the end of a 16 hour period. The results are in the following table:

on Bearing Weight Loss (Mg/25 sq. cm.)

Base OiH-product of Example 2. It!) Base Oil+product of Example 3. 0

. bamates, metal xanthates and thioxanthates, and the like.

frii syrer e aniple, the audition agents of our invention may be used in minerallubricating 7 oil in -conjunction with one or more of the following representativematerials:

, Barium tert.-octyl phenol sulfide Cobalt tert.-amyl phenol sulfide Tin salt of wax alkylated phenol sulfide The lubricating oil base stocks used in the comositions of this invention may be straight mineral lubricating oils or distillates derived from paraflinic, naphthenic, asphaltic or mixed base crudes, or, if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed. The 0118 may be refined by conventional methods using acid, alkali and/or clay or other agents such as aluminum chloride, or they may be extracted oils produced, for example, by solvent extraction with solvents of the type of phenol, sulphur dioxide, furfural, dichloroethyl ether, nitrobenzene, crotonaldehyde, etc. Hydrogenated oils or white oils may be employed as well as synthetic oils prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products. In

certain instances cracking coil tar fractions and coal tar or shale oil distillates may also be used. Also, for special applications, animal, vegetable or fish oils or their hydrogenated or voltolized products may be employed, either alone or in admixture with mineral oils.

For the best results the base stock chosen should normally be that oil which without the new additives present gives the optimum performance in the service contemplated. However, since one advantage of the additives is that their use also makes feasible the employment of less 8 cosity at 210 1''. For the lubrication of certain low and medium speed Diesel engines the general practice has often been to use a lubricating oil base stock prepared from naphthenic or aromatic crudes and having a Saybolt viscosity at 210 F. of to seconds and a viscosity index of 0 to 50. However, in certain types of Diesel service, particularly with high speed Diesel engines, and in gasoline engines, including aviation engine service, oils of higher viscosity index are often preferred, for example, up to 75 to 00, or even higher, viscosity index.

In addition to the materials to be added according to the present invention, other agents may also be used, such as dyes, pour depressors, heat thickened fatty oils.. sulfurized fatty oils. organo-metallic compounds, metallic or other soaps, sludge dispersers, anti-oxidants, thick-, eners, viscosity index improvers. oiliness agents,

resins, rubber, olefin polymers, voltolized fats,

voltolized mineral oils, and/or voltolized waxes and colloidal solids such as graphite or zinc oxide, etc. Specific examples of such other agents include dibenzyl disulfide, 2,6-di-tert.-butyl-4- methyl phenol, sulfurized sperm oil, diamyi trisulflde, voltolized sperm oil, polyisobutylene, polymerized lauryl methacrylate, sulfurized wax oleflns, and the product of treating a sulfur monochloride diisobutylene reaction product with phenol. Solvents and assisting agents, such as esters, ketones, alcohols, aldehydes, halogenated or nitrated compounds, and the like, may also be employed.

Additives which are particularly desirable as plasticizers and defoaming agents are the higher alcohols having eight or more carbon atoms and preferably 12 to 20 carbon atoms. The alcohols may be saturated straight and branched chain aliphatic alcohols such as octyl alcohol (CaHnOH), lauryl alcohol (CmHisOH), cetyl alcohol (CroHsaOH) h e p t a d e c yl alcohol (CrzHasOH), stearyl alcohol, sometimes referred to as octadecyl alcohol, (ClBHIiGOH) and the like;

satisfactory mineral oils or other oils, no strict rule can be laid down for the choice of the base stock. Certain essentials must of course be observed. The oil must possess the viscosity and volatility characteristics known to be required for the service contemplated. The oil must be a satisfactory solvent for the additive, although in some cases auxiliary solvent agents may be used. The lubricating oils, however they may have been produced, may vary considerably in viscosity and other properties depending upon the particular use for which they are desired, but they usually range from about 40 to seconds Saybolt viathe corresponding olefinic alcohols such as oleylalcohol; cyclic alcohols, such as naphthenic alcohols; and aryl substituted alkyl alcohols, for instance, phenyl octyl alcohol, or octadecyl benzyl alcohol or mixtures of these various alcohols, which may be pure or substantially pure synthetic alcohols. One may also use mixed naturally occurring alcohols such as those found in wool fat .(which is known to contain a substantial percentage of alcohols having about 16 to 18 carbon atoms) and in sperm oil (which contains a high percentage of cetyl alcohol) and although it is preferable to isolate the alcohols from those materials, for some purposes, the wool'fat, sperm oil or other natural products rich in alcohols may be used per se. Products prepared synthetically by chemical processes may also be used such as alcohols prepared by the oxidation of petroleum hydrocarbons, e. g., parafiln wax, petrolatum, etc. These assisting agents serve to enhance the detergent and sludge dispersive qualities and aid the solubility of the metal-containing additives and at the same time impart oiliness properties to the lubricating oil compositions.

In addition to being employed in crankcase I lubricants the additives of the present invention may also be used in extreme pressure lubricants, engine flushing oils, industrial oils, process oils, general machinery oils, greases and rust preventive compositions. Also their use in motor fuels, Diesel fuels and kerosene is contemplated. A particular application in this regard is their 9 use in motor fuels containing tetraethyl lead or other anti-knock agents.

The present invention is not to be considered as limited by any of the examples described herein which are given by way of illustration only, but it is to be limited solely by the terms of the appended claims.

We claim:

1. A liquid petroleum hydrocarbon product containing dissolved therein an amount sufficient to substantially stabilize said hydrocarbon product of a product obtained by reacting a sulfide of phosphorus with a polyvalent metal salt of a com pound of the formula Ar(OH) (SQ-,H) (R) group of suilicient chain length to impart oil solubility to said reaction product, said salt having'the hydrogen of the OH and SOsH groups replaced by a metal, the proportions of said sulmetal, and the reaction being conducted by heating the reactants together at an elevated temperature for a period of time sumcient to produce a reaction product which is substantially noncorrosive to copper.

2. A composition according to claim 1 in which Ar of the formula represents a benzene nucleus. 3. A composition according to claim 1 in which Ar of the formula represents a benzene nucleus, in which R represents an alkyl group of 16 to 20 carbon atoms, in which the sulfide of phosphorus is phosphorus pentasulfide, in which the metal of is calcium. and in which the atomic ratio of phosphorus and calcium in the reaction with the phosphorus sulfide is from 0.2 to 1.2. s 4. A mineral lubricating oil containing dissolved therein 0.1 to 2.0% of a product obtained by reacting about one-fourth molecular proportion of phosphorus pentasulfide with one molecular proportion of a compound of the formula where R is an alkyl group of 16 to 20 carbon atoms, the reaction being carried out by dissolving the calcium alkylated phenatesulfonate in xylene and refluxing the solution thus formed in the presence of the phosphorus pentasulfide for a period of about 3% hours.

5. A composition according to claim 4 in which the concentration of the additive in the lubricating oil is about 1%.

6. A petroleum hydrocarbon oil con dissolved therein an amount sumcient to substantially stabilize said oil of a product obtained by reacting a sulfide of phosphorus with a polyvalent metal salt of a sulfonated phenol having atleastonealkylgroupofchainlengthlumcient tion of phosphorus lar l0 to impart oil solubility to said reaction product, said salt having the hydrogen of the OH and SOaH groups replaced bya metal, the proportions of said sulfide of phosphorus and said metal salt being such that from 0.05 to 2 atomic proportions of phosphorus are present for each atomic proportion of metal, and the reaction being conductedby heating the reactants together at an elevated temperature for a period of time sufiicient to produce a reaction product which is substantially non-corrosive to copper.

7. A composition consisting essentially of a petroleum lubricating oil and a reaction product of a sulfide of phosphorus and a polyvalent metal salt as defined in claim 6, the amount of said reaction product in the composition being 25% to I 8. A composition consisting essentially of a petroleum lubricating oil and a product obtained by reacting about one-fourth molecular proporpentasulfide with one molecuproportion of a compound of the formula where R is an alkyl group of 16 to 20 carbon atoms, the reaction being carried out by dissolving the calcium alkylated phenatesulfonate in xylene and refluxing the solution thus formed in the presence of the phosphorus pentasulfide for a period of about 3 hours, the amount of said reaction product in the composition being,.25% to 75%.

9. A composition according to claim 1 in which the petroleum hydrocarbon product is a lubricating oil.

10. A composition according to claim 1 in which the sulfide of phosphorus is phosphorus pentasulflde and in which the metal of the metal salt is a divalent metal of group II of the periodic table.

11. A composition according to claim 1 in which the sulfide of phosphorus is phosphorus pentasulfide and in which the metal of the metal salt is calcium.

JOHN G. McNAB. DILWORTH T. ROGERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number