US2381912A - Compounded mineral oil - Google Patents

Description

Patented Aug. 14, f

COMPOUNDED MINERAL OIL I Frank W. Kavanagh, Bruce B. Farrington, and James 0.'Clayton, Berkeley, Calif., assignors, by

mesne assignments, to California Research Corporation, San Francisco, Calif., a corporation of Delaware No Drawing. Application March 29, 1943,

Serial No. 481,004

Claims.

and particularly of lubricating oils having desired characteristics, has been the subject of extensive research and investigation in recent years. Generally speaking, the compounding of hydrocarbon oils to obtain desired characteristics involves empirical phenomena. and the action of untested combinations of difl'erent types of compounding agents cannot be predicted.

A characteristic which has been the subject of extensive investigation is the tendency of hydrocarbon oils to deteriorate or partially decompose and oxidize when subjected to high temperatures.

This deterioration is evidenced by the deposition of adhesive deposits on hot metal surfaces over which the hydrocarbon oil may flow. Itis important that resistance to such deterioration be imparted to hydrocarbon oils, particularly to lubricating oils, in order that-such compositions may be relatively free from the tendency to form such deposits even under high temperaturesand severe operating conditions. A direct result of this type of deterioration during lubrication of internal combustion engines, such as engines of of operation of engines without the necessity of major overhauls heretofore occasioned by stuck pistons, wear of pistons and cylinder walls, or corrosion of bearing metal alloys.

The broader aspects of the invention involve the discovery that sulfur anti-oxidants of the character hereinabove defined and metal phenates cooperate to give new results inhydrocarbon oil compositions. Hydrocarbon oils containing this combination of ingredients have greater stability under various operating conditions than do oils containing either of these types of ingredients alone. For example, the same stability is not obtainable with 1% of a metal salt of a phenol or with 1% of the sulfur anti-oxidant in a lubricating oil as is obtained with oi the metal phenate and of the anti-oxidant in the same lubricating oil.

Metal phenates, which may be added to hydrocarbon oils such as mineral lubricating oils to provide one component of the new composition of matter herein claimed, comprise the alkali, alkaline earth and other metal phenates. Ex-

amples of such metal phenates are sodium phenates, potassium phenates, beryllium phenates, calcium phenates, strontium phenates, barium phenates, magnesium phenates, zinc phenates, cadmium phenates and aluminum phenates.

The metal phenates are preferably formed from high molecular weight phenols of the type formula:

the Diesel type, is the tendency of the oil to cause or permit the sticking of piston rings.

The crankcase lubricant in internal combustion engines is subjected to extremely severe operating conditions, andin engines of the Diesel type the lubricant encounters in the piston ring zone temperatures of from approximately 425 to 650 F. ;and pressures from the oxidizing combustion gases as high as 750 to 1150 unds per square inch. .In its more specific aspects the present invention is directed to .the improvement of hydrocarbon lubricatlng oils by imparting thereto increased resistance to deterioration by heat at high temperature levels on the order of those above mentioned. a

We have discovered that organic sulfides, when used in combination with metal phenates, impart to hydrocarbon oils a number of highly desirable properties and improve the lubrication and operation of internal combustion engines. More particularly, it has been discovered that a lubricating oil containing both a metal phenate and such a sulfur compound permits longer periods 56 ll I! in which u, v, w, a: and y are selected from the group consisting of hydrogen, hydrocarbon, oxy and hydroxy radicals. The phenol preferably contains at least one alkyl group having at least four carbon atoms. The term hydrocarbon radicals used in the above connection is intended to include alkyl, aryl, alkaryl, aralkyl and cyclic non-benzenoid groups; and the term oxy radicals refers to a group in which the hydrogen of a hydroxy radical has been replaced by esterification, neutralization, or the like. Although phenols containing at least one alkyl substituent are preferred, the invention does not preclude compounds containing no alkyl groups and embodies the substitution of aryl, alkaryl, aralkyl and cyclic non-benzenoid groups as well as com jugated rings in the aromatic nucleus to which the phenolic hydroxy group is directly attached- Examples of specific metal phenates which may be utilized comprise sodium lauryl phenate, sodium cetyl phenate; calcium lauryl phenate, calcium cetyl phenate, calcium di-amyl phenate, calcium heptyl phenate, calcium p-tertiary amyl phenate,

of the phenols, in the presence of sulfuric acid,

with an olefine or. an olefine polymer, such as ditri and tetra butylenes, or di, tri and tetra isobutylenes. The alkylated phenol may then be reacted with the proper metal or metal ion, or the sodium or potassium salts of the alkyl phenol may be reacted with the proper metal ion to obtain the desired salt. The preparation of the metal phenates comprises no part of this invention and may be effected by those skilled in the art without undue difliculties.

Among the sulfur compounds that may be used in accordance with the invention in combination with metal phenates are the aryl sulfides, disulfides, and polysulfides and the alkyl sulfides, disulfides and polysulfldes. In general, sulfur compounds having the grouping -o-(s),.o

when used in oils in combination with metal phenates, are embraced by the invention. In the above partial formula, 11. is a whole number at least equal to one.

Thus di-alkyl, di-aryl, di-aralkyl and mixed alkyl aryl, alkyl aralkyl and aryl aralkyl monosulfldes (thioethers), disulfides and polysulfides are comprehended by the invention. Also, organic thiocyanates are comprehended by the invention.

, Among the di-alkyl (including cycloalkyl) sulfur compounds may be mentioned dibutyl, diamyl, butyl ethyl, dihexyl, dicyclohexyl, dioctyl, didecyl, dilauryl, dicetyl and diparaffin monosulfides, disulfides and polysulfides. Among the di-aryl compounds may be mentioned diphenyl, di-cetylphenyl and diphenol monosulfides, disulfides and polysulfides. Among the diaralkyl compounds may be mentioned dibenzyl and di-phenylethyl monosulfides, disulfides and polysulfides. Among the alkyl aryl, alkyl aralkyl and aryl aralkyl compounds may be mentioned, respectively: cetyl phenyl monosulfide (C16H33SC6H5) and the corresponding disulfide and polysulfides, and also amyl hydroxyphenyl monosulfide and the corresponding disulfide and polysulfides; amyl benzylmonosulflde (C5H11-S--CH2.C6H5) and the corresponding disulfide and polysulfldes, and also cetyl benzy monosulfide and the corresponding disulfide and polysulfides and phenyl benzyl monosulfide and the corresponding disulfide and polysulfldes. Among the thio cyanates may be mentioned butyl,

octyl, lauryl, cetyl, phenyl, cetylphenyl and benzyl thiocyanates.

Polysulfides as used herein include the trisulfides, and higher polysulfides. Illustrative examples of these are dibutyl, diamyl, dibenzyl and diphenyl trisulfldes.

For purposes of the present invention those sulfur compounds are preferred which contain only aliphatic carbon atoms attached to the sulfide group, with mixed aliphatic aromatic sulfides (such as cetyl phenyl monosulfide) being next in order of-preference. Preferably di-aliphatic sulfides containing at least 8 carbon atoms in at least one aliphatic group are employed, examples being dioctyl, didecyl, dilauryl, dicetyl and cetyl ethyl monoand disulfides. The aliphatic groups of the preferred sulfur compounds may be straight or branched open chain or cyclic groups, and they may be saturated or unsaturated. Also, the said aliphatic groups may be substituted, as by phenyl, chloro, hydroxy and amino groups.

By diparaffin sulfides as used herein is meant substances of the character of those produced by condensing a chlorinated parafiin wax with sodium or potassium monoor polysulfide to replace part or all of the chlorine with sulfur. Paraffin thiocyanates may be similarly derived from chlorinated paraffin wax and an alkali metal thiocyanate.

As has been previously pointed out, the present invention embraces the discovery that hydrocarbon oils containing both the metal salt of a phenol and a sulfur compound as characterized above have new and unpredictable advantages. The properties of hydrocarbon oils containing both a metal phenate and said sulfur compound are; illustrated by the following discussion and The Strip corrosion test" referred to in the table below was carried out as follows: Glass tubes 2 inches in diameter and 20 inches long were immersed in an oil bath, the temperature of which was automatically controlled to within plus or minus 1 F. of the test temperature, which was 300 F. Approximately 300 cc. of oil under test was placed in each tube and 'air was bubbled through it at the rate of 10 liters per hour. Strips of the different types of bearing metal were placed in the oils; in most cases the copperlead and cadmium-silver bearing alloys were tested simultaneously in the same sample of oil. The weight loss of each strip was recorded. Before weighing, each strip was washed in petroleum ether and carefully wiped with a soft cotton cloth. The duration of the test was 72' hours. At the conclusion of the test, the neutralization number of the oil was measured.

The base oils used were an SAE 30 solvent treated Pennsylvania (parafilnic) oil and a white oil. The calcium cetylphenate was the normal calcium salt of an alkylatecl phenol produced by alkylating phenol in the presence of sulfuric acid with a butylene polymer averaging C16 per molecule (three butylene units), separating the alkylated phenol and forming the calcium salt. The sulfurized calcium cetyl phenate was the product of reacting the foregoing calcium cetyl phenate in concentrated solution in mineral lubricating oil with gram atom of sulfur per gram mol of phenate at a temperature of 300-320 F. for one hour. The reaction mixture was then air-blown until it no longer discolored a copper strip. A sufiicient amount of the reaction mixture was then incorporated in the white oil to produce a finished oil containing 0.5% of sulfurized calcium cetyl phenate.

dition agents, blooming agents and compounds for Y Strip corrosion test Neutraliza- Base oil Additives Cu-Pb, hours Gd-Ag, hours tion number of used oil Penn. SAE 30 Ni] 1.9 6.0 22.0 0.0 0.2 0.2 1.39 D 0.5% (la cetyl phenate 12. 6 52. l 100. 1. 1 20. 1 103. 6 1. 80 1% cetyl ethyl monosulflde 7. 0 6. 8 19. 7 0. 5 0. 8 l. l l. 21 0.5% Ca cetyl phenate+1% cetyl ethyl monosulfide 9. 8 5. 8 9. l 0. 4 0. 2 0. 2 0. 79 1% dibenzyl disulfide +2. 5 39. 3 42. 5 0.1 +0. 1 +0. 1 1.42 0.5% Ca cetyl phenate+l% dibenzyl dlsulfide +1. 8 +4. 5 5. 6 0. 1 0. 1 0. 0 0. 70 l 0 n-butyl thiocyana 2. 0 2. 6 2. 3 0. 1 0. 2 0. 2 0. 39 D 0.57 Ga cetyl phenate+l% n-butyl thiocyanat 9. 4 10.3 10.6 0.1 0. 1 0. l 1. 28 White 011 5% s ized Ca cetyl phenate +1. 1 +0. 8 l0. 0 0. 0 0. l 0. 8 0.35 Do 0.5% suliurized Ca cetyl phenate+l% cetyl ethyl monosulfide. +0. 7 +0. 6 +0. 9 +0. 1 0. 0 0. 0 0. 05 Penn. SAE 30- 0.6% Ca cetyl phenate+0.25% diphenyl monosulflde l3. 3 36. 4 66. 3 +0. 4 16. 9 54. 6 0.83 Do 0.5% Ca cetyl phenate+0.25% cetyl phenyl monosulfide 3. 6 23. 0 47. 1 0. 1 4. 8 5. 0 0.29

( 1tHn-SC|Hi)- Besides the above indicated and other advantages possessed by the combination in hydrocarbon lubricating oils of metal salts of phenols and the sulfur compounds of the invention, a given amount of the combination also imparts to such oils a greater stability against oxidation than is imparted by an equal amount of either component alone.

A variety of base oils may be employed for compoundingqwith the additives of this invention, e. g., paraflinic, naphthenic and mixed base oils. I

The proportion of sulfur. compound which may be added to mineral lubricating oils, according to the principles of the present invention, may vary widely depending upon the uses involved and the properties desired. As little as 0.05% by weight of various of the sulfur compounds gives measurable improvements, particularly as respects the color stability of the compounded oil. From approximately 0.1% to 2% of the compound may be added to lubricants containing metal phenates where stability at high temperature comprises the principal property desired. Solutions containing more than 2% of the compounds in mineral oils may be utilized for various purposes, e. g., for preparing lubricating greases and concentrates capable of dilution with lubricating oils and the like. Likewise, the proportion of metal phenates present in compounded lubricants may vary widely depending on the uses involved and the properties desired. As little as 0.1% by weight of the phenate gives measurable improvement, although from approximately 0.25% to approximately 2% phenate is preferred where the compounded oil is to be used as a crankcase lubricant forinternal combustion engines. As much as 50% or more by weight of various of the phenates may be dissolved in mineral oil for the purpose of preparing a concentrate capable of dilution with lubricating oils and the like. Concentrates containing high percentages oi the phenate and a sulfur compound comprises a convenient method of handling the ingredients and may be used as addition agents for lubricant in general as well as for other purposes.

Wherever in the claims an organic sulfide is referred to, it is intended to include mono-, di and polysulfides. v a

The combination of ingredients of this invention may be present in hydrocarbon oils containing other compounding agents-such as pour point enhancing the viscosity index of the hydrocarbon oil. The invention in its broader aspects embraces mineral hydrocarbon oils containing, in addition to the metal 'phenate and the sulfur compound, thickening agents and/or metal soaps in greaseforming proportions or in amounts insuflicient to form grease, as in the case of mineral castor machine oils or other compounded liquid lubricants.

While the character of the invention has been described in detail and numerous examples of the composition given, this has been done by way of illustration only and with the intention that no limitation should be imposed on the invention thereby. It will be apparent to those skilled in the art that numerous modifications and variations of the illustrative examples may be effected in the practice of the invention which is of the scope of the claims appended hereto.

We claim:

1. A lubricant comprising a major proportion of a petroleum oil of lubricating viscosity, about 0.1 to 2% by weight based on the oil of a polyvalent metal salt of an alkylated phenol and about 0.05 to 2% by weight based on the oil of an aliphatic sulfide.

2. A lubricant comprising a major proportion of a petroleum oil of lubricating viscosity, about 0.1 to 2% by weight based on the oil of an oilsoluble alkaline earth metal salt of an alkylated phenol and about 0.05 to 2% by weight based on the oil of a dicetyl sulfide.

3. A lubricant comprising a major proportion of a petroleum oil of lubricating viscosity, about 0.1 to 2% by weight based On the oil ofan oilsoluble alkaline earth metal salt of an alkylated phenol and about 0.05 to 2% by weight based on the oil of a diamyl sulfide.

. 4. A lubricant comprising a major proportion of a petroleum oil of lubricating viscosity, about 0.1 to 2% by weight based on the oil of an oilsoluble alkaline earth metal salt of an alkylated phenol and about 0.05 to 2% by weight based on the oil of a dibenzyl sulfide.

5. A lubricant comprising a major proportion of a hydrocarbon oil of lubricating viscosity, about 0.1 to 2% by weight based on the oil of a polyvalent metal salt of an alkylated phenol and about 0.05 to 2% by weight based on the oil of an allphatic sulfide.

FRANK 'W. KAVANAGH.

BRUCE B. FARRINGTON. JAMES O. CLAYTON.