US2462616A - Lubricating oil containing an antioxidant - Google Patents

Description

i atentecl Feb. 22 i945;

UNITED STATES ATENT OFFICE LUBRICATING OIL CONTAINING AN ANTIOXIDAN T ware No Drawing. Application December 5, 1944, Serial No. 566,772

4 Claims.

This invention relates to lubricants and other organic materials subject to deterioration in the presence of oxygen, and it relates more particularly to mineral lubricating oil compositions for use as crankcase lubricants for internal combustion engines containing addition agents suitable for retarding the deterioration of such oils and for lowering the pour point of the same.

In accordance with the present invention a new class of organic derivatives of boric acid are described which are particularly useful as additives for mineral lubricating oils used in internal combustion engines, in which they act as inhibitors of oxidation and deposition of varnish on hot metal surfaces and as agents for substantially reducing the pour point of the base oil. They are particularly useful in inhibiting the normal corrosiveness of the oil when in contact with copper-lead, cadmium-silver and other similar bearings now widely used in automotive engines. these compounds are likewise suitable as antioxidants in organic materials generally where the organic material is known to be susceptible to deterioration in the presence of oxygen.

It has been proposed in the art to use various esters of boric acid, such as tributyl borate, triamyl borate, trilauryl borate, triphenyl borate and the likes as additives for inhibiting the corrosiveness of lubricating oils toward hard metal alloy bearings. It has been found, however, that when alkyl borates or aryl borates with only short alkyl side chains are used as additives for oils, the ester is hydrolyzed by means of moist air, with the result that boric acid is precipitated in considerable quantities from the solution as a solid precipitate. By comparison, the additives of the present invention are [practically free from a tendency to hydrolize in this manner.

The new class of antioxidant compounds are long chain alkylated aryl borates, and those which are especially effective are the wax-alkylated phenyl borates. The new class of additives may be defined more precisely by the general formula (RAT) mHnBOB where Ar is any aryl nucleus, e. g., a benzene, biphenyl or naphthalene nucleus, R represents at least one open chain alkyl radical, all of such radicals containing a total of at least 16 carbon atoms, m is an integer from 1 to 3, n is 0, 1 or 2, and m+n equals 3. The above formula is intended to include also compounds in which various substituent atoms or groups may be attached to the aromatic nucleus or to the side chain, such as alkyl, aryl, carboxyl, hydroxyl, alkoxy, aroxy, sulfhydryl, nitro, ester, keto, thicether, amino or aldehydo groups, halogen atoms, etc.

A highly preferred class of compounds are the wax-alkylated phenyl borates, which may be readily obtained by first preparing a wax-alkyl- 'ated phenol, as by reacting phenol with a chlorinated wax, and then reactingthe wax-alkylated phenol with boric acid. Compounds of this type which contain two or more wax chains on the phenyl nucleus are preferred, Various ratios of wax-alkylated phenol to boric acid may be used in the preparation, ranging from 1:2 to 3:1. It should be understood that more than one phenyl group may be attached to a single wax chain, as when a wax containing chlorine atoms at a number of points in the chain is reacted with phenol to produce a wax chain containing several phenol substituent groups, and that compounds so produced are intended to be included within the scope of the above general formula.

Alkyl phenols whose borate esters may be employed in the present invention include: Wax alkylated phenol, wax alkylated naphthol, wax alkylated cresol, cetyl phenol, octadecyl phenol (stearyl phenol), di-tert.-octyl phenol, isohexadecyl phenol, and Cm-Czo branched chain alkyl phenols obtained by alkylating phenol or a cresol with a refinery butene polymer oil. Borates of the corresponding alkyl phenol sulfides may also be employed.

Generally, the additives of the present invention are most advantageously blended with lubricating oil base stocks in concentrations between the approximate limits of 0.02% and 5.0% and preferably from 0.5% 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 operating conditions of the engine in which the lubricant is to be used.

A number of examples of the preparation of the new compounds of the present invention and of the intermediates used in the preparation of such compounds will be described in detail, and data PRODUCTION OF CI-EORINATED WAX EXAMPLE 1 1 kg. of refined paraffin wax (M. P. 122 F.) was placed in a reaction flask and the wax melted over a hot plate. When the temperature of the melted wax reached 240 F. the hot plate was removed and the flask placed on a balance and chlorine gas passed into the wax at such a rate that the temperature remained about 200 F. throughout the entire chlorination process. When the weight had increased by a little more than 198 g. the flow of chlorine was stopped and dry nitrogen was passed in to remove the excess chlorine and H01. This was continued for about 2 hrs. The resulting product (product I) was found to contain 17.46% chlorine.

EXAMPLE 2 2 gallons of chlorinated wax, obtained by chlorinating semi-refined wax (M. P. 118 F.) at 200 F. by a process similar to that described in Example 1 and containing 13.5% chlorine when melted completely, was poured into a round bottomed flask. This was placed on a steam bath and nitrogen blown through for about 2 hours. The product was found to contain 12.83% chlorine (product HA).

1 gallon of product IIA after standing for about weeks was found to be mostly liquid at 131 C. The liquid portion was siphoned off into a separate vessel, This liquid portionwas found to contain 13.60% chlorine (product IIB).

PRODUCTION OF WAX PI-IENOLS EXAMPLE 3 50-0 grams of chlorinated wax prepared as in Example 1 (product I) was placed in a 3-necked flask with stirrer. reflux condenser and thermometer. 70.5 grams of phenol was added, and a smaller flask containing grams of AlCls was attached to one neck of the reaction flask by means of Gooch tubing. The phenol-chlorinated wax mixture was heated to 65 C. and maintained at this temperature during the addition of the AlCls over a 1 hour period. The mixture was then slowly heated to 150 C. over a period of 1 hours; During this heating HCl was evolved in large quantities. Heating was continued for 3 hours more at 150 C. and the mixture Was then cooled to about 30 C. and 1 liter of petroleum naphtha (B. P. mil-240 F.) was added. The solution was poured into water and acidified with HCl. The mixture was shaken thoroughly to remove the AlCls. It was necessary to add isopropyl alcohol to break the emulsion. The mixture was washed several times with water and the upper layer was then distilled to remove the solvent. The distillation Was begun at atmosphericpressure, then moderate vacuum was applied carefully when the vapor temperature rose above 100 C. After the bath temperature had risen to 250 C. the solution was distilled at about 1.5 mm. pressure until the temperature of the bath had reached 225 C. The residue weighed about 465 grams. (Product IIIA.)

312.3 grams of product IIIA was distilled to remove the unreacted chlorinated wax. The dis- 4 tillation was carried out at less than 1 mm. pressure and continued until the distillation temperature rose to 260 C. The residue weighed 276.8 grams. (Product HIB.)

EXAMPLE 4 500 grams of chlorinated wax (product IIA) was placed in a reaction flask with stirrer and return condenser and 56.4 grams of phenol was added. The mixture was heated to- 65 C. and then over a period of one hour 15 grams of AlCla was gradually added from an Erlenmeyer flask connected to a side neck with Gooch tubing. The mixture was slowly heated at C. and

maintained at that temperature for 3 hours, after which it was partly cooled and 1 liter of naphtha was added. The naphtha solution was washed three times with water and dried over anhydrous CaClz. The solvent was stripped ofi at atmospheric pressure. The temperature was raised to 250 0., moderate vacuum being first applied and then high vacuum (less than 1 mm.) to remove the unreacted chlorinated wax as a distillate until a temperature of 260 C. 'was reached. The residue weighed 342 grams. (Product IV.)

EXAMPLE 5 560 grams of chlorinated wax (product I) was placed in a reaction flask equipped with stirrer, return condenser, and thermometer and 67 grams of phenol was added. The mixture was heated to 65 C. and 15 grams of anhydrous AlCh was added gradually over a period of 1 hour, employing the same technique as in previous examples. The flask was gradually heated to 150 C. and held between 150 and C. for over 3 hours. The flask was allowed to cool partially and 1 liter of naphtha was added. The mixture was poured into a separatory funnel, allowed .to stand EXAMPLE 6 500 grams of chlorinated wax (productIIA) was placed in a reaction flask with stirrer, reflux condenser, and thermometer and 56.4 grams of phenol was added. The mixture was heated to 65 C. and 15 grams of anhydrous AlCla was.

added in small proportions over a 'period of 1 hour. The mixture was gradually heated to 150 C. and held at 150-160 C. for over 3 hours. The mixture was allowed to cool partially and 1 liter of naphtha added. The solution was poured into a separatory funnel, allowed to stand overnight and washed twice with water and dried over CaClz. The solvent and a small amount of water present were removed by distillationunder moderate vacuum until a bath temperature of 250 C. was attained. The residue was dissolved in naphtha and filtered through I-Iyflo. The solvent and unreacted materials were distilled off under lessthan 1 mm. pressure up to a distilling temperature of 230 C. The residue weighed 400 grams. (Product VI.)

EXAMPLE 7 500 grams of chlorinated wax (product 11B) was placed in a reaction flask with stirrer, return condenser, and thermometer, 60 grams of phenol was added and the whole heated to 65 C. To this solution 15 grams of anhydrous AlCla was added over a period of hour. The mixture was gradually heated to 150 C. and held at that temperature for 4 hours, after which 1 liter of naphtha was added. The solution was decanted to a separate flask and NH3 gas passed in for A.; hour to decompose any A1013 present. Air wa blown in to remove the excess of NH3. The solution was filtered and the volume of the filtrate then reduced by vacuum distillation until 605.8 grams of residual naphtha solution remained.

The residual naphtha solution was Washed with dilute HCl and three times with Water, and then dried by refluxing with a water trap. The solvent was removed by distilling in vacuum over a boiling water bath, the residue weighing 534 grams. (Product VII.)

PREPARATION OF WAX PHENYL BORATES In Examples 8 to 15 will be described several preparations of wax phenyl borates, by reacting the wax phenols prepared as described above with boric acid in various proportions and under varying conditions of procedure.

EXAMPLE 8 95.5 grams of wax phenol (product IIIA) was placed in a reaction flask and 500 cc. of xylene added. A stirrer, thermometer, and return condenser with trap were attached and the mixture refluxed several hours to remove any water which may have been present. The refluxing was stopped and '7 grams of powdered H3BO3 was added while the mixture was still hot. There was considerable reaction immediately with liberation of water. The mixture was refluxed overnight, then cooled and filtered. The solvent was removed from the filtrate by moderate vacuum and heated to 250 C. in a metal bath. The residue weighed 105 grams. (Product VIII.) This product was an amorphous, dark colored solid, somewhat gelatinous when cooled.

EXAMPLE 9 100 grams of wax phenol (product IV) was dissolved in 500 cc. of toluene and placed in a reaction flask equipped with stirrer, return condenser and water trap. The solution was refluxed to remove any water which may have been present. 10 g. of HsBOs was added and the mixture refluxed overnight. The solution was filtered from excess H3303 and the solvent distilled from the product at a pressure of 1 mm. until the bath temperature reached 190 C. The residue weighed 103.6 g. (Product IX.)

EXAMPLE 10 100 g. of wax phenol (product 1113) was dissolved in 500 cc. of toluene and placed in a reaction flask equipped with stirrer, return condenser and water trap. The solution was refluxed to remove any water which may have been present. 3.56 g. of HsBOa was added and the mixture refluxed for 6 hours, water formed during the reaction being removed through the trap. All of the H3BO3 dissolved with the exception of a few crystals on the bottom of the flask. The solution was placed in a Claisen flask and the solvent removed by distillation under moderate vacuum up to an oil bath temperature of 190 C. The residue weighed 101.1 g. (Product X.)

EXAMPLE 11 In the same manner as in Example 9,

200 grams of wax phenol (product V) was dissolved in 750 cc. of mineral spirits having a boiling range of 300 to 410 F. and placed in a reaction vessel equipped with stirrer, thermometer, return condenser, and water trap. 14.3 grams of H3303 was added. The mixture was heated to 155 F. and held at this temperature overnight. The solution was filtered with the aid of Hyflo and the solvent partially removed by distillation under vacuum, then 800 grams of a refined paraflinic type mineral lubricating oil of S. A. E. 20 viscosity grade was added and the remainder of the mineral spirits removed by further distillation under house vacuum (150-200 mm. pressure) using a maximum bath temperature of 290 C. A maximum vapor temperature of 142 C.was reached. The residual oil solution was further treated by heating it for 4 /2 hours at 150 C. with 15 grams of boric acid, a stream of nitrogen being blown through the mixture at the same time to facilitate removal of water. A filter aid (Hyflo) was added and the mixture filtered to give a clear oil concentrate containing about 20% of wax phenyl borate. (Product XII.)

EXAMPLE 1.3

200 grams of wax phenol (product VI) was dissolved in 1 liter of mineral spirits having a boiling range of 300 to 410 F. and placed in a reaction flask containing 12 grams of HaBOa. A stirrer, thermometer, and return condenser with water trap were attached and the mixture refluxed to remove water. The mixture was maintained at 150 C. overnight without refluxing and then filtered with the aid of Hyflo. The mineral spirits was partially removed by vacuum distillation (150-200 mm.) 600 grams of S. A. E. 20 mineral lubricating oil was added and the vacuum distillation was continued. The distilling temperature rose to a maximum of C. with a bath temperature of 240 C.

The oil solution was further treated by heating it for 4 /2 hours at C. with 15 grams of boric acid, a stream of nitrogen being blown through the mixture at the same time to facilitate removal of water. A filter aid (Hyflo) was added and the mixture filtered to give a clear oil concentrate containing about 25% of wax phenyl borate. (Product XIII.)

EXAMPLE 14 300 grams of Wax phenol (product VIIB) was placed in a reaction flask equipped with stirrer,

. thermometer, and return condenser with water aeea eic EXAMPLE 15 '200 grams of waxphenol (product VIIB) and 1 liter of toluene'were placed in a reaction flask equipped with stirrer. thermometer, and return condenser with water trap.

10.3 grams of s Tabl ll Borate Ester Amount of Precipitation Ocigadlefiyl borate (Product A voluminous precipitate-small -HaB'O3 was added and the mixture stirred and l T rt.-Octylphenyl borate Volummo s r c it t o d refluxed over the week-end. All of the H3803 rioduct XVI). T 1p Mm M W had disappeared. The toluene was removed by 33333; r 3 -T g'gggg ggg gi moderate vacuum distillation over a water bath Product XI. No precipitate. and finally under high vacuum. The residue ggggggggkaghazy weighed 194.5 grams. (Product XV.) Product XIV Slight powdery precipitate. In t following table are summarized some Product XV i gl Solutwn and Slight fine p p a 0. t e more pertinent data relating to the WaX Tricthylborate Immediate voluminous precipitate. phenyl borate products whose preparation has Tmmylbmte been described above.

Table I Per cent Acetyl M01. Wt.

Per cent Wax Phenol/ Wax/Phenol 1 1n No. of from Product No. Cl 113x01 Ratio Wax Wax Acetyl Hzalg rb 1;(a)t1o 7 Phenol Phenol N o.

. EXAMPLE l6 POUR'POINT TESTS Tertiary octyl phenol was prepared by alkyla- 30 EXAMPLE 1 tion of phenol with diisobutylene. 206 grams of tertiary octyl phenol was dissolved in 824 grams of S; A. E. grade solvent refined paraffinic type mineral lubricating oil and treated with 61.8 grams of boric acid. The mixture was heated at 150 C. for 5 hours with stirring, nitrogen being blown through the mixture to facilitate water removal. The product was then filtered using Hyflo filter aid, to give a clear oil concentrate containing of tertiary octyl phenyl borate. (Product XVI.)

EXAMPLE 17 A solution of 27.0 grams (1 mol. proportion) of commercial stearyl alcohol (octadecyl alcohol) in 810 grams of S. A. E. 20 grade paraffinic type mineral lubricating oil was treated with 20.6 grams (3 mol. proportions) of boric acid. In essentially the same manner as in Example 16 the mixture was heated and stirred and blown with nitrogen for 5 hours at 150 C. and then filtered, giving a clear oil concentrate containing 25% of tri-octadecyl borate.

MOIST AIR TEST EXAMPLE 18 In the following series of tests, water-washed airwas passed through oil solutions containing 1% each of various borate ester products to determine the efiect of such .moist air in hydrolyzing the ester and precipitating the bOIic acid from the oil solution. For each test 1% of the ester was dissolved in a base oil consisting of a refined parafrlnic type lubricating oil of 20 viscosity grade, and 100 cc. of such solution was placed in a suitable vessel. Air was then bubbled through a bottle containing water and then through the oil solution at a rate of 4 to 7 cc. per second for a period of two days in each test, the apparatus being kept at room temperature. The results given in Table II show the amount of precipitate observed as the result of the hydrolysisof the ester. A number of alkyl and alkaryl esters of boric acid have'thus been compared with the waX-phenyl borates produced in the processes described above.

Measurement was made of pour points of the various wax phenyl borate products in a clay finished Pennsylvania neutral distillate light lubricating oil stock with a normal pour point of +30 F. 0.5% and 1% solutions were thus tested. The results are shown in Table III.

Table III Pour Point of Solution in Oil Product No.

VIII. 35 -ss 1x. -35 5 -25 -35 +10 0 -35 -5 +15 -10 +15 INDIANA LIFE TESTS EXAMPLE 20 Blends .of lubricating oils containing additives prepared in accordance with the present invention were submitted to the standard Indiana oxidation test, described in S. A. E. Journal, vol. 34, page 167, (1934). 0.5% of borate ester was present in each oil blend. Theresults are shown in Table IV. The values given represent the number of milligrams of sludge formed from 10 g. of oil at the end of various periods during which the test was run. The base oil used in each case was well refined, solvent extracted paraflinic typemineral lubrieating oil of S. A. E. 20 grade. A

. During each test the varnish forming tendency of each oil blend was also determined in the following manner: In each oil sample tube a glass plate about 3" by 1" was placed. At the end of the 96 hour period'the plate was removed, washed with naphtha; airdried and then weighed to determine the amount'ofyarnish' deposited. The milligrams ofvarnish: obtained in each test are also given in Table- IV.

Table IV [Sludge (Mg/l gfof oil)]i on 24 4s 72 96 Indiana Mg.

Hours Hours Hours Hours Hour 1 Varnish Base Oil 0 0 16 55 63 3. 6 Base 0il+Product VIII 0 0 0 Trace 96 0.1 Base Oil-l-Product IX 0 Trace Trace 43 78 2. 3 Base OiH-Product X. 0 0 Trace 57. 8 76 0.8 Base Oi1+Product XL 0 Trace Trace 22. 4 83 1. 2 Base Oil+Product XIL 0 Trace 8. 1 68. 7 73 3.1 Base Oil-l-Product XIII. 0 0 Trace 48. 4 77 3. 3 Base Oil+Product XIV"... 0 Trace Trace 66. 0 76 2. Base 0il+Product XV 0 Trace Trace 35. 8 79 3.1

1 Hours to form 10 mg. of sludge (determined by interpolation).

BEARING CORROSION TESTS EXAMPLE 21 Blends of the wax phenyl borate products pre pared by the methods of the foregoing examples in a lubricating oil base consisting of a Well refined solvent extracted paraffinic type mineral lubricating oil of S. A. E. viscosity grade, the blends containing 0.5% and 1.0% of the additive, and a sample of the unblended base oil, were submitted to a corrosion test designed to measure the efiectiveness of the products in inhibiting the corrosiveness of a typical mineral lubricating oil toward the surface of copper-lead bearings. Th test was conducted as follows:

500 cc. of the oil was placed in a glass oxidation tube (13" long and 2 diameter) fitted at the bottom with a A bore air inlet tube perforated to facilitate air distribution. The oxidation tube was then immersed in a heating bath so that the oil temperature was mantained at 325 F. during the test. Two quarter sections of automotive bearings of copper-lead alloy of known weight having a total area of sq. cm. were attacked to opposite sides of a stainless steel rod which Was then immersed in the test 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. At the end of each four-hour period the bearings were removed and were washed with naphtha and weighed to determine the amount of loss by corrosion. The bearings were then repolished (to incrase the severity of the test) reweighed, and then subjected to the test for an additional four-hour period. The cumulative weight losses of all the bearings used in a given test at the end of the various four-hour periods are given in Table V.

Table V The lubricating oil base stocks employed in the blended lubricating oils of this invention may be straight mineral lubricating oils, or distillates derived from paraffinic, 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 oils may be refined by conventional methods using acid, alkali and/or clay or other agents such as aluminum chloride, or they may be extracted oil produced, for example, by solvent extraction with solvents of the type of phenol, sulfur dioxide, furfural, dichloro ethyl 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 application, 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 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 Cumulative Bearing Weight Loss (mg/25 sq. cm.

surface) Cone.

Oil Blend percent 4 8 12 Hours Hours Hours 24 Hours Hours Base Oil BasebOil-i-Product VIII. o

Base Oil+Product IX".

satisfactory"solvent for the additive, although in some cases auxiliary solvent agents may be used. The lubricating oils, however they 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 150 seconds Saybolt viscosity at 210 F. 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 45 to 90 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 engine service, oils of higher viscosity index are often required, for exampleup to 75 or 109, or even higher, viscosity indexi" In addition to-the materials to be added accordingito the present invention, other agents may also. be used such as dyes, pour depressors, heatgthickened fatty oils, sulfurized fatty oils, org-ano metallic compounds, metallic or other soaps, sludge dispersers, antioxidants, thickeners, viscositylndeximprovers, oiliness agents, resins, rubber, olefinzpolymers, voltolized fats, voltolized mineral oils, and/or voltolized waxes and colloidal solids such as graphite or zinc oxide, etc. Solvents and assisting agents, such as esters, ketones, alcohols, amides, nitriles, amines; aldehydes, halogenated or nitrated compounds and the like may also be employed.

Assisting agents which are particularly desirable for. reducing foam and for plasticizing concentrated oilsolutions of the additives are the higher alcohols having eight or more carbon atoms and preferably12to 20 carbon atoms. The alco hols may-be saturated straight and branched chain aliphatic alcohols such as octyl alcohol, CsI-InOH,--lauryl.alcohol, C12H25OH, cetyl alcohol, C1eH33OH, stearyl alcohol, sometimes referred to as octadecyl-alcohol, C18H37OH,-a-nd the like; the corresponding olefinicalcohols such as oleyl' alcohol; cyclic-alcohols, such as naphthenic alcohols; ,and aryl substituted alkyl alcohols, for instance phenyl octyl alcohol, or octadecy1 benzyl alcoholor. mixtures of these various alcohols, which may be pure or substantially pure synthetic alcohols. One may also use mixed-mate urally occurring alcohols such asthose found in- WOOL fat. (which is known to contain a substantial' percentageof'alcohols having'about 16 to 18 In addition to being employed in crankcase.

lubricants and in extreme pressure lubricants, the additives of the present invention may also be used in industrial lubricants, process oils, en'- 12 gine flushing oils, turbine oils, insulating and transformer oils, steam cylinder oils, slushing and rust preventive compositions, and greases. Also their use in motor fuels, Diesel fuels and kerosene is contemplated. Since these additives exhibit antioxidant properties and are believed also to possess ability to modify surface activity, they may be employed in asphalts, road oils, waxes, fatty oils of animal or vegetable origin, soaps, and plastics. Similarly, they may be used in natural and synthetic rubber compounding both as vulcanization assistants and as antioxidants, and

where Ar is an aryl nucleus, R represents at least one alkyl radical, the alkyl radicals containing a total of at least 16 carbon atoms, m is an integer from 1 to 3, n is 0, 1 or 2, and m-l-n equal 3.

2. A composition ofmatter consisting essentially of a mineral lubricating oil and an oxidation inhibiting proportion of a compound of the formula (RAY) mHnBO3 where Ar is an aryl nucleus, R represents at least one-alkyl radical, the alkyl radicals containing a total of at least 16 carbon atoms, m is an integer from 1 to 3, n is 0, 1 or 2, and m-i-n equal 3.

3. Acomposition of matter according to claim 2 in-which R of the formula is a wax radical and Ar is abenzene nucleus.

4.. A:composition of matter consisting essentially of a mineral; lubricating oil and an oxida tion inhibiting quantity of a wax alkylated phenyl borate.

LAWRENCE T. EBY. LOUIS A. MIKESKA.

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

UNITED STATES PATENTS Number Name Date 2,154,098 Loane et al Apr. 11, 1939 2,260,337 Prescott Oct. 28, 1941 2,260,338 Prescott Oct. 28, 1941 2,300,006 Prescott Oct. 27, 1942 2,312,208 Clayton Feb. 23, 1943 2,316,903 VanEss Apr. 20, 1943 2,326,496 ReiiT Aug. 10, 1943 2,333,871 Lincoln Nov. 9, 1943 2,346,157 Farrington Apr. 11, 1944 2,357,287 Reiff l Sept. 5, 1944 2,383,605 Lieber Aug. 28, 1945