US2308502A - Compounded oil - Google Patents

Description

attests This invention relates to new and useful compositions of matter and involves a composition comprising a hydrocarbon oil such as a mineral oil containing a polyvalent metal salt of co types of acids, either alone'or in admixture with other compounding agents of the same or diflerent type.

The production of improved hydrocarbon oils, and particularly of lubricating oils having tiesired characteristics, has been the subject of extensive research and invmtigation. Generally speaking, the compounding of lubricating oils to obtain desired characteristics involves empirical phenomena. The present invention pro= vides a compounded lubricating oil having one 26 time to high temperatures and pressures in the presence of metals, air or oxygen or hydrocaricon in: combustion products. Deterioration of the'character referred to manifests itself in diverse edects, depending upon the nature and 30 x ylate. The ailsyl hydroflvg'roup is preferably no degree oi refinement oi the hydrocarbon oil and upon the environment to which it is subjected. in Diesel engines, the edect is manifested by piston ring sticking. In these engines. the er:-

of a lubricating oil to such temperatures v 5,

as its total)" F. in the presence of 1- combustion gases at or lldd lhs. mr square inch causes't e deposition of oil degradation pructs of such a cementitious character as to actively tahe piston v as out of service. in automobile engines the deposition of sludge in the crankcase oils and the fo 11:. of ish" on the cylinder walls of the engine are observed to be the result or ion d i a: 1. WW5

(Cl. t52 32) I V occurring in the degradation process. The corroslon of hard metal bearing surfaces of the type represented by cadmium-silver and copper-lead alloys also is a dimculty encountered from the deterioration of lubricating oils in internal combustion engines or other services. The adverse eflect of deterioration of hydrocarbon-client elevated temperatures is ag ravated by the fact that improvements in the mechanical arts have brought about increasing severity in the conditions to which the oils are subjected. It has also been the practice in the lubrica t oil art to improve other properties of lubrits by adding ingredients to mineral oil fractions for ecing the oiliness characteristics, the wear reducing action, the fllm strength, the color stability, and the viscosity index of lubricating oils.

It is an obiect of the present invention to improve one or more of the above discussed prorties of lubricating oils (1. e:, stability agt piston ring sticking, "varnish formation, slut.

corrosivity to metal bearing surfaces, oiliness, wear reduction, strength, color stability, or viscosity index) by incorporating in hydrocarbon oils a polyvalent metal salt of certain types of organic acids.

The lubricating oils of this invention are characterized by the presence therein of a poiyvalet metal carboirylate having an alias hydro stituent near a carbonyl group of the whoa:-

carbonyl group oi the compcun it is intended 4.0 to .desate compounds having at least one lay drosyi group in at least one or the positions alpha, beta or as with respect to a carboml group of the cpopnd. ltsemplary com.- pounding acts of t invention are polyvaosidation and/or polymerization phenomena as lent metal salts of acids characterised by the pres ence therein of chemical groups such as the following:

-cc-on t:b--c-on E H t -b--o-on -b-b--( :--o-on in a on ta tn 9) The various unsatisfied valences shown on the carbon atoms in the formulae may be attached to hydrogen, a carbon atom, or to an acyclic organic radical.

The addition to a lubricating oil of a small amount of polyvalent metal carboxylates ha an alkyl hydroxy subetituent near a carboxyl group edects an improved stability in the .oil when the same is subjected to high temperatures and/or pressures in the presence of oxygen and metals. This appears to be true when the hydroxy radical is in the delta or even epsilon position, as well as when it is in the alpha, beta or gamma position, with respect to a carbonyl group. However, improvements in the properties oi lubricating oil are obtained when a hydroml group is in an alpha, beta or gamma position, which are not obtainable with the hydroxyl group more than about three carbon atoms removed from the carbonyl group. The edectlveness of the OH constituent decreases in the order of the positions recited.

Examples of hydroxy carbowlic acids from which the oil-improving agents of this invention may formed are: alpha hydroxy propionic acid (lactic acid), beta hydroxy propionic acid; alphahydroxy butyric acid, beta hydroxy butyric acid, gamma hydrom butyric acid; alpha hydroxy valerlc acid, beta hydroxy valeric acid, gamma hydroxy valeric acid; alpha hydroxy caproic acid, beta hydroxy caproic acid, gamma hydroxy caproic acid; alpha hydroxy enanthic acid, beta hydroxyenanthic acid, gamma hydroxy enanthic acid; alpha hydroxy capryllc acid, beta hydroxy capryllc acid, gamma hydrorw caprylic acid; alpha hydroxy capric acid, beta hydroxy capric acid, gamma hydroxy capric acid; alpha hydroxy lauric acid, beta hydroxy lauric acid, gamma hydroxy lauric acid; alpha hydroxy myristic acid, beta hydroxy myristic acid, g hydroxymyristic acid; alpha hydroxy pslmitic acid, beta hydroxy palmitic acid, gamma hydrow palmitic acid; alpha hydroxy stearic acid, beta hydrom stearlc acid, gamma hydrow stearic acid; alpha hydrow arachidic acid, beta hydroxy arachidic acid, gamma hyoo draw arachidic acid; tartronic or hydroxy malonic acid and the several alkylic tartronic acids,

such as methyl tartronic or isomallc acid, ethyl tartronic, propyl and isopropyl tartronic; the gamma hydrowalkyllc malonic acids; malic acid and its homologues, for example, alpha hydroxypyrotartarlc acid, beta methyl malic acid, alpha beta methyl ethyl malic acid, isopropyl malic acid and the paraconlc acids; alpha hydroxygiutaric acid, beta hydroxyglutaric acid; alpha hydroxy adipic acid; alpha hydroxy sebacic acid; tartaric acid' and its isomers; citric acid, dlhydroxytartaric acid; mucic acid; and hydroxy acids produced by the oxidation of petroleum hydrocarbons, such as parafiin wax, petrolatum,

313.11g!!! asoatoa naphthenic base lubricating oils, selective sol; vent extracted naphthenic base lubricating oils; mixed base (e. g., Mid-Continent) lubricating oils, solvent extracted mixed base lubricating oils, paramnic base (e. g., Pennsylvania) lubricating oils, solvent extracted paramnic lubrlcating oils, where the oxidation process is controlled so as to produce at least one hydroxyl group near the carboxyl group of said acids.

From the above it is to be understood that in its broader aspects the invention embraces metal monocarboxylates having only one alkyl hydroxy substituent near the carbonyl group of the compound or having a plurality of alkyl hydroxy substituents, some or all of which are near the carbonyl group of the compound, and that the invention also embraces metal polycarboxylates having only one alkyl hydroxy substituent near a carbonyl group of the compound or having a plurality of allryl hydroxy substituents, some or all of which are near a carbonyl group of the compound. In the metal polycarboxylate compounds all or only part of the carboxyl groups may be neutralized'with metal, and when only part is so neutralized the remaining ones may be neutralized by esteriflcation, by amino groups or the like.

The compounds utilized in this invention may be prepared by methods known in the art; for example, by direct reaction of a suitable polyvalent metal compound with the corresponding free acid or by double decomposition of the sodium or potassium carboxylates with a suitable compound of the polyvalent metal. Also, the compounds may be prepared by first forming a metal carboxylate of an unsubstituted acid and then introducing an hydroxyl group in an alkyl portion of the molecule at a point near a carbonyl group thereof. Suitable methods of introducing hydroxy groups into alkyl chains are known in the art.

The metals whose alkyl hydroxy substituted carboxylates are useful for the purposes of this invention preferably have valences from two to four inclusive, and the salts of calcium, barium,

magnesium, aluminum, chromium, cobalt, lead, manganese, tin and zinc are of particular utility. Although the alkali metals, sodium and potassium, are not precluded from the broadest aspects of the invention the carboxylates of these latter metals tend to cause the compounded oil to form emulsions with water and, where the lubricating service to he encountered is the lubrication of internal combustion engines, such a tendency is undesirable. Further, the alkali metal carboxylates are frequently more corrosive to bearing metals than one would desire.

Among the compounds which may be incorporated in lubricating oils according to the principles of this invention are the following: calcium, barium, magnesium, aluminum, chromium, cobalt, lead, manganese, tin and zinc salts of alpha, beta, and gamma hydroxy substituted lactic, butyric, valeric, caproic, heptanoic, caprylic, capric, lauric, myrlstic, palmitic, stearic, and arachidic acids; also salts of the foregoing metals and tartronic, methyl tartronic, ethyl tarj suhstituent near a carbonyl group ,soasoa neutral carbomlates may be utilised. lBy basic carhomiates is meant counds in which the carboryiio acid groups are at m an amount w i cientto wholly satisfy the normal valence valence which may be attached to an hydroxyl group; By a neutral sal is meant compounds i the metal, thereby leaving an unsat metal terifled thiophosphorous acids:

= which th carboxylic acid groups and the metal are present in stoichiometrical proportions so that the normal valence of each is fully satisfied. The invention likewise does not preclude carboxylates containing unsaturated carbon-to-carbon bonds, but compounds which do not polymerize are preierred.

This invention also embraces lubricating oils" contalning, in combination with poiyvalent metal carboxylates having an alkyl hydrow substituent near a carbonyl group of the compound, that is, in combination with each and every one oi the salts hereinbeiore disclosed, one or more of the iollowing types of compounds:

l. Carboiwlate esters having an allryi hydroxy of the comund;

2. Metal salts of organic acids, such as (a) Polyvalent metal salts of higher iatty or aliphatic acids;

(b) Metal salts of naphthenic acids; (c) Metal salts oi oil-soluble substituted phenols; (01) Metal salts of carbomlic acids containing an aryl substituent; d. Corrosion inhibitors and anti-oxidants ch as-'- (a) Polyhydroxy phenols, conde ring phenols, alkyl substituted phenols, and

naturallyi 1 it inhibitors which y be extracted from late d petroleum oils;

(b) Nitrogen communds comprising aryl mm? (diaes, diaryl amines), nitroso amines, cycle-aliphatic and condtion products of aldehydes or ketonw with aromatic lt cu: 1|

.(c) genated organic compounds com-.

prising aryl ethers, aryl he and m hetones:

(d) oi polycarbouylic ids having two carbonyl groups no more 1 1; two carimn ato art, and esters of carbomlic acids having an t carbon-to-carbon bond conjugated with the carbowl group:

(e) Oil-soluble organo-metaiiic compounds of metals selected irom Groups II,

IILIV and V of Mendel's Periodic Table;

(i) Sulfur, selenium and tellurium compounds-such as aryl mercap, aryl sulfides, aryl disulfides, aryl polysuiildes, aryl thioesters, a1 w rs, allryl mercaptans, moncsulfldm,

5. Polyvalent metal oxides having an alkyl or cyclo-alkyl group directly attached to the oxygen thereof.

Among the carboxylate esters having an alkyl hydroxy substituent near a carbonyl group of the compound which may be utilized in combination with each and every one oi the foregoing metal carboxylates are: the methyl, ethyl, propyl, butyl,

amyl, hexyl, heptyl, octyl, nonyl, lauryl, dodecyl,

tetradecyl, cetyl, and octadecyl esters of alpha or beta hydroxy propionic' acid, and the corresponding esters of alpha, beta, and gamma hydroxy butyric, valeric, caproic, enanthic, caprylic, capric, lauric, myristic, palmitic, stearic, and arachidic, as well as the corresponding esters of tartronic, tartaric and citric acids.

Among the metal salts of organic acids which may be utilized in combination with each and every one of the foregoing metal carboxylates having an alkyl hydroxy 'substituent near a carboxyl group of the compound are: aluminum laurate, aluminum oleate, aluminum stearate, aluminum ricinoleate; zinc laurate, zinc oleate, zinc stearate, zinc ricinoleate; tin laurate, tin oleate, tin stearate, tin ricinoleate; magnesium lam-ate, magnesium oleate, magnesium stearate, magnesium ricinoleate; calcium laurate, calcium oleate, calcium stearate, calcium ricinoleate; chromium laurate, chromium oleate, chromium stearate, chromium ricinoleate; aluminum naphthenate, zinc naphthenate, magnesium naphthenate, cobalt naphthenate, cadmium naphthenate, tin naphthenate, manganese naphthenate; aluminum, zinc, tin, magnesium, calcium and chromium salts of substituted phenols oi the type formula:

in which u, v, to. sand y are selected from the group consisting oi hydrogen, alkyl, aryl alkaryl. aralkyl and cyclic non-benzenoid radicals which y or may not be pure hydrocarbon substituents; aluminum phenyl stearate, zinc phenyi rate, calcium phenyl steal-ate, chromium p enyl stearate; aluminum naphthyl stearate,

zinc naphthyl stearate, tin naphthyl stearate,

-- to, chromium naphthyl stearate: aluminum enyl laurate, zinc phenyl laurate, tin phenyllaurate, magnesium phenyl stearate, chromium alpha benzal stearate; aluminum alpha benzal laurate, zinc alpha benzal laurate, tin alpha benzal laurate, magnesium alte, tin phenyl stearate, magnesium phenyi' t esium naphthyl stearate, calcium naphthyl pha benaal laurate, calcium alpha benzal laurate, chromium rlpha benaal laarate.

Among the polyvalent metal salts of acids of phosphorus containing an organic substituent which may be utilized in combination with each and every one of the foregoing metal carboxylates are the aluminum, calcium, barium, strontium, chromium, and magnesium salts oi substituted acids of pentavalent phosphorus oi the following formulae:

where R and R may be alkyl, aryl, alkaryl, aralkyl or cyclic non-benzenoid radicals which may or may not be pure hydrocarbon constituents.

Among the polyvalent metal oxides having an alkyl or cyclo-alkyl group directly attached to the oxygen thereof which may be utilized in combination with each and every one of the foregoing metal alkyl hydroxy carboxylates are: calcium amylate. calcium hexylate, calcium heptylate, calcium octylate, calcium decylate, calcium dodecylate, calcium tetradecylate, calcium cetylate; magnesium amylate, magnesium hexylate, magnesium heptylate, magnesium octylate, magnesium decylate, magnesium dodecylate, magnesium tetradecylate, magnesium cetylate; aluminum amylate, aluminum hexylate, aluminum heptyl ate, aluminum octylate, aluminum decylate, aluminum dodecylate, aluminum tetradecylate, aluminum cetylate; barium amylate, barium hexylate, barium heptylate, barium octylate, barium decylate, barium dodecylate, barium tetradecylate, barium cetylate; zinc amylate, zinc hexylate, zinc heptylate, zinc octylate, zinc decylate, zinc dodecylate, zinc tetradecylate, zinc cetylate.

Among the beneficial efiects which flow from the incorporation of a metal salt or a mixture of metal salts of the above described alkyl hydroxy acids in a hydrocarbon oil of the lubricating oil class is the prevention of piston ring sticking, or its marked postponement, undervery severe motor conditions, as for example, in Diesel engine or in aircraft spark or compression ignition engine operations.

In the tests whose results are summarized in Table I, a single cylinder Lauson gasoline sparkignition engine, 2% inch bore and 2 inch stroke, loaded with fan dynamometers, was operated under extremely severe conditions, designed to develop fully the tendency of the crankcase lubricant to deteriorate with gum formation and piston ring sticking: operation was at 1600 R. P. M.; engine jacket temperature was maintained at 375 F.; crankcase oil temperature was maintained at 220 F'.; at periods of hours the operations were interrupted and the condition oi the piston rings determined. In Table I, the base oil referred to as "Western 30" was an acid-refined lube stock of California origin; A. P. I. gravity 21.4; viscosities at 100 and 210, 662 seconds and 50.6 seconds, respectively, Saybolt Universal. To this base oil were added the various salts in the amounts indicated, by weight. The base or uncompounded oil referred to as Pennsylvania 30 was a solvent refined stock of Pennsylvania origin, A. P. I. gravity 28.6"; viscosities at 100 and 210 F. of 519 and 66 seconds, respectively,

Baybolt Universal.

aacatua Tame I Prevention or postponement of piston ring sticking Home to Relative Relative Oil (smearing ringslot piston oticldng cleanliness Wcstemliii 00 Poor Poor. w potassimn cetyl 00+ Good Good. +0.02%rriagneeium oetyl 60+ Feir rat.

tartrate. w almmiuum oetyl 60+ Poor Poor. +0.50% calcium oatyl 120+ Verygood... Very good.

+0.20% calcium cetyl 60+ Poor Poor.

mucatc. +0.34% potassium oetyl 120 Good Fair.

citrate. fififimagnesium cetyl 00+ I auz. Poor. +g 5 2 aluminum cetyl 00+ Good Fair. +gi6t2Z2 calcium dioetyl 120+ do 000a. +0.63% mlcium ulpha- 60+ ram-urm.

eicosyltertrate.

calcium oetyl 105+ Goodm. Do in a +0.50% calcium oetyl 00+ Very good Very good.

phenom-+0.50% calcium oetyl tartrate. +0.50% calcium oetyl 60+... .do Du.

phonic-+0.50% calcium dicet lcitrate. +0.50 calcium cetyl ..do Do.

phenate+0.25%calcium dicot lcitrate. +0.50 0 calcium oetyl l20+. do. Du.

phenete+0.50% calcium alpha-eioosyltartrete. +003% calcium alpha 60+ Fa1r Fair.

hydroxy steal-ate. Pe lvania30 30 Poor Poor.

%tacalcium cetyl 60+ Good Do.

calcium oetyl 00+ Very good Very good. pbenate+0.50%calcium dioat lcitmte. +0.63%? calcium alpha 00+ Fair. Fair.

hydroxy stcarate.

Norm-A plus sign following a stated number of hours in the antepenultlmate column indicates free rings at the conclusion of a test of the stated hours duration.

An additional benefit to be derived from this invention is a decreased corrosivity toward bearing metals, particularly those of the cadmiumsilver and copper-lead type. This diminution in corrosivity is particularly marked if the corrosivity of oils compounded with unsubstituted polyvalent metal carboxylates is compared with the corrosivity oi the same oil compounded with the same amount of the corresponding polyvalent metal carboxylate having an alkyl hydroxy substituent therein according to the principles of this invention. This decrease in corrosivity is so extensive in many instances that the compounding agents of this invention not only are themselves non-corrosive in lubricating oils but actually reduce the corrosivity of uncompounded oils which normally become corrosive during use, e. g., highly paramnic lubricating oils or highly refined oils, such as selective solvent extracted lubricating oils. As has been previously indicated herein, where reduction in corrosivity is a significant factor the alkyl hydroxy substituent should preferably be in the alpha position with respect to a carboxyl group of the compound, less preferably in the beta position, and of decreasing desirability and effectiveness in the gamma, delta and epsiion positions in the order named.

In the corrosion tests whose results are summarized hereinafter, thin sheets of the indicated bearing metals were cut into strips (copper-lead, 1%" x 1%" x 33 cadmium-silver, /2" x 1%" x 1 and these strips were immersed in the exemplified oils carried in 2" x 20" glass test tubes;

twt tithes were carried in an oil bath maintmed at 000 0". 2 1 0. Each test tube contained new we 0:. 000 cc. oi oil. and air was bubbled thronah each tuhe at the rate or liters per hour. ht the end oi each of three 24-hour mrioda, the strips were removed from the oils, -1! with mtroletm ether and careiully wiped wlthaeoit cotton cloth; weight losses oi the ships were measured in connection with the welhht oi each individual strip. The duration of the 1 wm-th hours, and the weiaht losses tabulhted -i are 1 tw ioiind at the end of the '12- hour mriod, except as indicated.

To illustrate the pronounced reduction in corrosion edeet hr the compounds of this invention as compared with various unsubstituted carbonrlatee. the iollowinr data are elven:

Tatar H re mwa- Oil s Cu-Pb Cd-Ag Western oh 8. A. E. 30 (naphthenio base) 13. 0 0. 4 +00% omcium stem-ate 131. 9 180. 5 +1 aluminum dine hthenete 07 113 130 119 120 12. 1 l9. 0. 2. l 8. 5 0. 4 5. 5 0. 5 2. 6 l. 4 +0 5. 0 0. o

iecte 135. 2 222 Y .5 0 03.5 41.6 +0.75 calcium out? phenate 100.6 216.4 +0.5 miclum oaty tam-ate.-. 1.3 0. 2 +0.45% calcium oetyl citrate l8. 1 14. z

httention is directed to the fact that each of the salts in the above table having an alkyl hydrow eroun near a carbonyl group (i. e... the alpha hrdrory stearate. the citrates, and the tartratw) is hi oterited by extremely low corrosivity as compared with the unsubstituted carboxylates.

The lollowine additional data establish the relative non-corrosiveness and, in some instances. the actual corronon inhibiting properties oi the Wllnds oi this invention:

Tenth m hedhctioa oi cow-calcite to hearing metals .0 still iurther heneht derived from the addition oi the metal salts oi this invention to hydrocarhon oils is a marked lessening of color instnhllitr upon exposure of the compounded oils to heat in the absence oi metals.

in the tests whose results are smrized in lahle W, samples of the compounded oils were held in slate new" F. for six hours. The oils r' .0010! on increase ter 1+. +0.50% calcium cetyl phenate +0.50% calcium dicotyl citrat 2l+ +0.00% calcium cotyl phcuate +0.50% calcium cotyi 1 +0.25? calcium cot l hoe hate calcium camamm r v p 2% +0.25% calcium cetyl phosphate +0.50% calcium dice lclmm 1+ +0.25 0 calcium cetyl phmphate +0.60% calcium +8 cat 1 pheuate +0 2197 calcium cetyl 1 'n "hm +0.40% calcium cetyi tar-hm 2+ 0% calcium cat 1 pbeuate '+0.%% calcium cetyl h hate +0. 0 calcium dioetyl citrate 1% .533: calcium cctyl phone-ta +0.36% calcium catyl ghosphate +0.00% calcium eetyl male 1-- +c l l%wdi-iscamyl tartrate +0.50% calcium dicetyl 1 re +l.0% didsoemyl termite +0.18% calcium oetyl cm- 4 +10% di-isoamyltartmte +0.51% a lcium cetyl succinam 2%- +iilufi dtlsoamyl tartmte +0.60% calcium cstyl l m +1.0 0 :ii-lsoamyl tartmtc +0.50% calcium cetyl y mu m: a

+10% di-lsoamyl mum +0.10% calcium alpha 1 #1 di isoam l5EJ+6WYfifJ i '05" I sicoi en lsuccin i s "8--.. )5 +1. Jeoamyl tartrate +0.15% calcium cetyl 4;-

so +0.03% calcium elpha-hydroxy ntearate 1- In 1m. .5. :0 w rived from the incorporation oi the metal salts oi the invention in hydrocarbon oils. by reason of an enhanced oiliness" and/or an increased load carrying capacity of the oils so compounded.

in the tests whose results are summarized in Table V, the figures reported under Weeks wear" are those obtained in the operation of a Weeks wear testing machine, in which a inch steel ball is pressed against a 1% inch steel cylinder which is rotated at 000 R. P. M. and which dips into the oil being tested; the duration of the test is 16 hours and the body of oil is held at 300 F.; the results are reported in inches oi wear x 10, as measured on the cylinder. The firm-m rte-d under Film streneth" are those obtained in the operation of a modified 'llimhen machine similar to that described in the S. A. E. Journal. volume 20, page 53, 1028; the results are reported in pounds at failure. "their 0 Wear resistance and film strength Weeht Oil WW 70 83 too me e00. 100

cases still iurther benefits may he de- Still further, the ability of hydrocarbon oils to resist oxidation, i. e., absorption of oxygen when exposed thereto at superatmospherlc temperatures and pressures, is in many cases enhanced and oxygen absorption postponed bythe incorporation-in the oils of the metal salts of the invention.

In the tests whose results are reported in Table VI the oils referred to were subjected to the "Oxidator test, particularly described in the Journal of Industrial and mgineering Chemistry, volume 28, page 26, 1936.v These tests were carried out at 340 E, which-condition may be noted as extremely severe. The results of the tests are reported in cubic centimeters of omgen absorbed per 100 grams of the respective oils at the periods of time indicated.

. Tasha VI Reduction of orgaenvabsorpiion Oxygen absorption Oil l'hr. 2 hrs. 2% hrs.

W WU 200 330 +038 135 235 230 +0. l 80 200 270 87 150 175 55 70 +0. 18 45 75 +0. 60 55 +0.28 magnesium cetyl citrate- 135 190 +0.52 aluminum eetyl citrate.. 24 65 03 +0.50 calcium dioetyl citmte 20 +0.63 calcium alpha-eicosyltartrate--. 105 122 +0.50 0 calcium cetyl malaise 22 d0 +0.5 0 calcium stem-ate... 400+ Too rapid to +0.35% calcium ricinoleato; 325 400+ +0.63% calcium alphahydroxy sieai-ate. 50 i225 the production of increased wear, and in many instances actually decrease wear on cylinder walls and piston rings as compared with uncompounded mineral oils, and non-corrosivity as respects the chemical action of the compounded oil on bearing metals such as copper-lead and cadmium-silver alloys, together with the ability oi certain compounds and combinations to actually decrease corrosivity oi normally corrosive uncompounded oils, represents an array of advantageous properties which is quite rare in single compounding agents or simple combinations thereof.

Attention is particularly directed to the unpredictable excellence oi the results obtained with an oil compounded with both a calcium 1 phenate and an alpha hydrom carboxylate, such as calcium allryl citrate, as shown by the following data:

Timur V11 8. A. E. 30 Western oil ate cal on ring slot clogging --I Copper-lead corrosion mgmam aaoatoa These two types oi compounding agents cooperate to give results obtainable with neither alone.

A discussion and data on the preparation oi exemplary compounds and lubricants oi this invention may serve to guide those skilled in the art in the practice thereof.

The compounds may be prepared by a number of alternative methods which may involve, ior'ex-.

ample, (1) neutralization of an alkyl hydroxy acid with an alkali metal hydroxide, and'addition of a water-soluble polyvalent metal salt to an aqueous solution of the neutralized acid whereby precipitation of the desired compound is obtained; 'or (2) hydrolysis and saponiflcation oi the neutral ester to form an alkali metal salt oi the acid of the ester, and precipitation of the polyvalent metal salt from the saponifled product. Where polycarboxylic acids are utilized as the salt-forming agent, an acid ester may first be formed or the neutral ester partially hydrolyzed and saponified to obtain compounds from which polyvalent metal alml hydroxy carboxylates are formed. Specific examples are as follows:

Example 1.--Preparation oi calcium alpha hydroxy stearate from stearic acid. Eight hundred and fifty-two grams of commercial triple-pressed stearic .acid (equivalent weight=273) which had been recrystallized from ethyl alcohol, were intimately mixed with 40 grams of acid-free red phosphorus. This mixture was heated on a water bath in a flask equipped with a dropping funnel and a reflux condenser, which was vented through an aqueous ammonia trap (to absorb iii) bromine) to a vacuum line. When the stearic acid and phosphorus mixture had been heated sumciently to melt the acid, 430 cc. of anhydrous liquid bromine were slowly dropped into the reaction flask. The addition of bromine was carried out over a period of, 3 /2 hours at a temperature varying from F, initially to at the completion of the addition. Heating was contlnued at 200 F. for six hours after all the bromine had been added. The product of this reaction, impure alpha bromostearyl bromide, was slowly poured into cold water and the whole then warmed on a hot plate for about an hour to efiect hydrolysis of the acid bromide to the acid. The equation describing these processes are:

3RCH COOH P 5 613! 3RCHBi'COBr SHBr HPOa RCHBrCOBr Horf=RcHBrcooH HBr Alpha-bromostearic acid The alpha-bromo acid was Washed well with water and then talten up in petroleum ether.' This solution was separated from the water layer, I

washed several times by shaking with water, and illtered. The bromo acid was crystallized from the petroleum ether in 73% yield and gave the following analysis:

Observed Percent bromine 2a 8 23. ii Neutralization value 100 iii! The analysis indicates the presence oi about 8% the hydroxy acid are as follows:

accuses other (i to 3 mixture) in 30% overall yield. This product had the following analysis:

Theoretical Observed Baponiflcation number 194 194 Percent bromine i) Bromine numberuur. 0 V D The equations representing the preparation of ncmrcoon A O RCHOHCOO Alpha-hydroxystearic acid aqueous caustic potash and then' precipitating,

the calcium salt by adding calcium chloride solution. The washed and dried salt was obtained in 73% overall yield. The salt had an ash of 8.8% and c% bromine content.

Examples 2, 3 and d.-Compounds Nos. 2, 3 and i in Table m below were prepared by sterihcation oi the corresponding acid, partial saponihcation, precipitation of the calcium salt, and purification oi the precipitated salt as follows:

Formation of the dlcetyl ester (or tricetyl ester) -o grams (see Table VIII, horizontal column a) ct cetyl alcohol of hydroxyl number k, and i drama oi dior tricarboxylio acid were mixed and heated in a suitable flash equipped with a stirrer and a trap for collecting the water produced in the esteriflcation. The reactants were heated at an average temperature of 7 degrees Fahrenheit for it hours. During the last several hours of heating, nitrogen gas was bubbled through the reaction mixture'in some cases to iaciiitate completion of the reaction and removal at any remaining water. The rapidity and dearee oi completeness of the reaction were followed by measuring the volume of water in the trap. The product was obtained in 1 grams yield and was checked for completeness of reaction and purity by determining a saponification numher at and a neutralization value a.

No catalyst was employed in this reaction, but hydrochloric or suliuric acids can he used ior such purposes.

Partial eapouiflcution of the dior tri-cetpl eater-o prams oi ester prepared as in the above erample were washed with water to remove any unused acid (where the acid was sumciently water-soluble) in aura-iota, ethyl alcohol, the solution stirred and heated to q decrees Fahrenheit, and p it oi caustic potash in an alcohol or alcohol-water solution slowly added, the rate oi addition beind resulated in such manner that at no time was there an appreciable excess oi caustic prment, as shown by phenolphthalein indicator added to the solution. The rate oi samnifleation varies tor the diderent esters; the total time required is aiven in Table WI, horizontal column r.

The washed ester was dissolved- Precipitation of the calcium sclt.-The alcoholic solution from the partial saponification,

containing potassium salt, unreacted ester, and

cetyl alcohol produced in the reaction. was diluted with approximately an equal volume of water, the temperature brought to ice-170 R, giving a creamy suspension; and s araim of calcium chloride in water solution added with stirring. There may or may not be curding'oi the calcium salt, depending on the particular compound and the conditions of the reaction. The precipitated solid material was washed with water to remove potassium chloride and any unused calcium chloride, and was then dried.

Purification of calcium salt-The dry calcium salt was freed oi cetyl alcohol (produced in the partial saponification) and any unreacted ester by extraction with etlwl ether or other suitable solvent, giving a final yield of t grams of the calcium-alhvl hydrow carbomlate. The cetyl alcohol extracted from the crude salt was recovered for rm.

g lull-:1 for a The following equations are for the preparation of calcium cetyl tartrate:

( EOE +KOH=( HOH): +CwHasOH OOCMHM 00K Formation of calcium salt C 00 Grants [(J'JHOH); 1| Ca+2KC1 a non), +cac1i= Example 5.-Calcium dicetyl citrate was also made by preparing a partial or acid ester directly and neutralizing as iollows:

Formation of the partial eaten-38a grams of citric acid were mixed with 100 grams of cetyl alcohol and heated at 320 F. in a flask equipped with a stirrer and trap for catching the water produced in the reaction. Additional cetyl alcohol, onto a total of 5i?! grams, was added to the reaction mixture in apprommately 100 grams increments at one hour intervals. The total time required ior'the reaction was eight hours. The yield was 76? grams of crude acid ester. This product was washed with water to remove excess citric acid and a dried sample had a saponification number voi mo and neutralization numher of '75. These figures correspond to approximately t5% dicetyl citric acid.

Formation of calcium salt-The washed 85% dicetyl citric acid was suspended in water at a temperature oi 170 F. and slowly neutralized in the presence of an indicator with 80 grams of potassium hydromde in aqueous solution. The calcium salt was then precipitated by adding excess aqueous calcium chloride. The salt was washed iree oi potassium chloride and excess calcium chloride and dried. calcium salt was 383 grams, or dh% of theoretical, calculated on the basis of calcium dlcetyl citrate. The salt had an ash of 6.35%.

representative preparation The yield of dry a -we:

solution in oil Example Example Example Example 2 3 i ii alcium Calcium Calcium Calcium dioetyl cetyi oetyl dicatyl citrate tartrotc to citrate direct method g min 1641 547 h 205 205 no, i 2K8 384 38 i 1' 320 M 320 k 19 6 8 1 Yield of crude ster ;m 1273 1780 707 1 Yield of of theoretical based on I, m 03 81 51 {Sapom no. of ester 188 170 161 220 Theoretical value 188 193 ms 195 n Neutraliz. value of ester .c. l2 8 0 76 PARTIAL SAPONIFIOATION PROCESS AND MLAKING OF SALT Ester oi saponiilcation' "gm" 400 KOH ior saponiflcation "gm" 35 Avg. temp. oiss n F. 160

Time for saponiilcotiom. 30 min. C801] to make salt. ..gm 36 of salt "gm- M8 Yield in of theoretical 00 'Yield in overall of theoretical. 50

Teriiiip. during solution of salt concentrate in 400 0 0 Time of heating during solution in oil. minutes.

210 a 42 ll 80 1E0 180 min. 2 hrs.

d2 11 lid 75 5B 383 27 i6 00 $0 37 81 till) 260 250 5 5 5 r Preparation of compounded oil containinu the calcium salt-The dry calcium salt was made may contain as much as or more of the salt dissolved in the solvent. When oil is the solvent,

stirring and heating to a temperature of from 300 to 400 F. is desirable. The concentrate was then added to sumcient mineral lubricating oil to dilute to the desired final concentration and the whole was heated-at a" F. for 1) minutes (Table VIII) In the case of calcium cetyl tartrate particularly, it was necessary that the temperature u be high in order to destroy a false viscosity or thickening of the oilwhich resulted if a lower temperature was employed. For compounds of low solubility it is also necessary to aid solution by stirring at relatively high temperatures and for longer periods of time. The oil was finally filtered through a press preceded by centrifuging where necessary.

The proportion of the metal allay] hydrory carborylates added to mineral lubricatins oils may vary widely, depending upon the uses involved and the properties desired. fis little as 0.1% by weight of the metal alkyl hydrory carboxylate aives measurable improvements, althoush from approximately 0.25% to approximately 2% is preferred where the compounded oil is to be used as a crankcase lubricant for internal combustion engines. Similarly, the proportion of the carboxylate esters having an alkyl hydroily substituent near a carbonyl group of the ester may vary. widely but in general from 0.1% to 5% of the ester is utilized in combination with the metal alkyl hydroxy carboxylatea, and. more usually to 2% thereof is found desirable. More than 10% is regarded as unnecessary, crcept when a concentrate is being prepared for subsequent dilution with mineral oil to produce the finished lubricant. The proportion of metal salts of other organic acids, such as the aliphatic acids,

.naphthenic acids, phenolic acids, and aryl carboxyllc, likewise may vary from 0.1% to 5% and, more usually, from 0.5% to 2% when utilized in combination with metal alkyl hydroxy carboxylates. The corrosion inhibitors and anti-oxidants represented by the various types listed above under the heading "3 Corrosion inhibitors and anti-oxidants such as" may be present with the metal aliryl hydroxy carboxylates in an amount of from about 0.05% to 2%, or more. The polyvalent metal salts of acids of phosphorus containing an organic substituent when utilized in comblnation with the polyvalent metal alisyl hydrory carbonylatcs may be added in amounts from 0.0 to about 2%, or more. Usually 1% or low is found adequate. The polyvalent metal oxides having, an alhyl or cycloallryl group attached to the oxygen thereof may be added in amounts of from 0.05%. or less, to 5% and preferably 0.1% to 3% when used in combination with the metal allryl hydroiw carboxylates. In each of the above mtancca the proportions of insredients may be very materially increased when a concentrate is being prepared for subsequent dilution with lubricating oil. Proportions are given throughout this specification in per cent by weight based on the oil unless otherwise indicated.

In ncneral, metal alltyl hydrory carhonylatcs containin z. at least about ten carbon atoms are preferred. Where the organic allryl hydrory-pure esters are utilised in combination with the metal carbonylatcs and reduced corrosion is desired,'t he ester should preferably contain less than ten carbon atoms; where reduced friction at low rubbiny speeds is a paramount factor. more than ten carbon atoms in the ester are preferred; cooperation with the metal alkyl hydroxy carboxylateo to give increased stability against oxidation may be lubricating oils from Mid-Continent stocks. as

her organic solution containing relatively large oportions of the additive agents. The solvent 1y be hydrocarbon oils or the lubricating or less icous type or, if more suitable, an admixture th oil of certain other agents, such as aromatic 'drocarbons, alcohols, esters, ketones or ethers, rich are generally of low molecular weight and the aliphatic series. These latter blending ents may serve to improve the solubility rela- )nships or thelike or the compounds. Admixres of the addition agents and lubricating oils other solvents or carriers containing 50% or ore of the essential agents by weight may be us prepared and distributed for later blending .th the particular lubricating oil media to be it to use as occasion demands. In the prepara- Jn of either the finished oils of the invention or the bases or concentrates referred to, complete clear and homogeneous solution is not always icessary. Stabilizing or blending agents may be nployed to prevent sedimentation of the more i-lnsoluble addition agents. The possible detriental efiect of the presence of filterable insolue materials of this character, if they be present, determined largely by the particular conditions tending the contemplated use and their presice is not in all cases deleterious to the functiong oi the composition in its intended manner.

The compounded lubricant herein disclosed ,ay have one or more advantages depending upon 1e particular compounds selected, the proporons utilized, and the environment which the lbricating oil is to encounter. It should be obarved, for example, that even though a comounded oil may not be entirely non-corrosive to pper-lead or cadmium-silver alloys, other bearig metals may be little if at all affected by such JI'IOSiVe action. Hence, compounding agents or ambinations thereof which may not be particuirly desirable for one service, where corrosion at lgh temperatures becomes a factor of imporance, may nevertheless be highly useful and exremely advantageous in other services. Likerise, a compounding agent which may not be ufllciently powerful to adequately stabilize a parlcular oil stock against deterioration under the most severe conditions may be highly advanageous in such an 011 where the environment to e encountered is not so severe, as for example in urbine oils, cable oils, electric switch oils, transormer oils and the like. Further, the same comvounding agent may cooperate with other agents, iS disclosed hereinbefore, to adequately stabilize he oil even for the most severe service. The iresent invention in its broader aspects is thereore not limited to the particular compounding ngredients having the greatest stability or havng all of the advantages of the preferred agents )1 combinations of agents. The invention em- :races various of the less advantageous com- :ounding agents or combinations thereof which my find utility in particular applications where 111 possible improvements in properties of the oil may not be required or where the standard of performance may not be so high.

The compounding ingredients of this invention are not limited in their applicability to any particular base oil stock. The advantages herein disclosed may be obtained with various oil stocks, the selection of which will be determined by condition and services which the compounded lubricant is'to encounter. The compounding ingradients are useful not only in Pennsylvania oils or highly refined naphthenic base oils, but also in moderately refined naphthenic base oils or in 70, than about three carbon atoms removed from 9.

wall as in synthetic hydrocarbon oils, such as hydrogenated polymers of olefin hydrocarbons, orcondensation products of chlorinated alkyl hydrocarbons with aryl compounds.

The compounding ingredients of this invention may be utilized in hydrocarbon oils, con-- taining other compounding agents, such as pure point depressants, extreme pressure addition agents, blooming agents and the like. Also the compounds are useful in greases, e. g. a grease comprising a mineral oil and a sodium soap.

It is to be understood that the invention in its broader aspects does not preclude the use of substituted alkyl hydroxy carboxylates and that the term alkyl hydroxy is intended to define a compound in which the hydroxy group retains the essential characteristics of a hydroxyl group attached to a pure alkyl radical. However, substituents may be present in the polyvalent metal alkyl hydroxy carboxylates in a position which is so far removed from the hydroxy group asnot to substantially destroy the essential alkyl hydroxy characteristics of the hydroxy radical. The invention therefore includes polyvalent metal salts of substituted alkyl hydroxy carboxylic acids when the substituent present is not so close to the alpha, beta or gamma hydroxy radical as to substantially destroy its essential alkyl hydroxy characteristics. Thus functional groups, such as an aromatic ring positioned on an alkyl chain relatively remote (for example, ten or twelve carbon atoms removed) from the alpha, beta or gamma hydroxy radical, are regarded as falling within the scope of the invention in its broader aspects.

The term carbonyl group is usedthrough out the specification and claims to include an esteriiied or neutralized carboxyl group, i. e. the group where X may be either a metal or an organic radical.

Our copending application Serial bio. 322,946, filed March 8, 1940, is directed to those aspects of the present disclosure pertaining to salts of polycarboxylic acids.

While the character of the invention has been described in detail and numerous examples given, this has been done by way of illustration only and with the intention that no limitation should be imposed upon the invention .thereby. Numerous modifications and illustrations 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 composition comprising a major proportion of a hydrocarbon lubricating oil subject to deterioration, and from about 0.1% to 2% by weight of a metal alkyl monocarboxylate having an alkyl hydroxy' group no more than about three carbon atoms removed-from a carbonyl group of the carboxylate.

2. A composition comprising a major proportion or a hydrocarbon lubricating oil subject to deterioration, and from about 0.1% to 2% by weight of a polyvalent metal alkyl monocar boxylate having an alkyl hydroxy group no more carbonxyl group of the carboxylate.

3. A composition comprising a major proportion of a hydrocarbon lubricating oil subject to deterioration, and from about 0.1% to 2% by weight of an alkaline earth metal aliryl monocarbonylate having an aliryl hydrorry group no more than about three carbon atoms removed from a carbonyl group of the carboxylate.

4. A composition comprising a major proportion of a hydrocarbon lubricating oil subject to deterioration, and from about 0.1% to 2% by weight of a calcium alkyl monocarboxylate having an alkyl hydroiry group no more than about three carbon atoms removed from a carbonyl group of the carboxylate.

5. A composition comprising a major proportion of a hydrocarbon lubricating oil subject to deterioration, and from about 0.1% to 2% by weight of an aluminum allryl monocarborylate having an alkyl hydroxy group no more than about three carbon atoms removed i'rom a carbonyl group of the carborrylate.

6. A composition comprising a major proportion oi. a hydrocarbon lubricating oil subject to deterioration, and from about 0.1% to 2% by weight of a chromium allwl monocarbomrlate having an allwl hydroay group no more than about three carbon atoms removed from a carbonyl group oi the carborwlate.

7. A compounded lubricant subject to deterioration at elevated temperatures comprising a hydrocarbon oil and a small amount of a metal alhvl monocarboxylate sumcient substantially to inhibit said deterioration, said carbomlate being characterised by the presenceoi an'alkyl bydroxy group not more than about three carbon atoms from a carbonyl group of said carboryiate to reduce the corrosivity of said carbomlate to -where R is a radical of allryl structure, B is an a hydrocarbon oil and a small amout of a metal alkyl carboxylate suflicient substantially to inhibit said deterioration, said carbowlate being a polyvalent metal salt of an acid characterized by the presence of .the group .9. A compounded lubricant subject to deterioration at elevated temperatures comprimng 11. A composition comprising a hydrocarbon lubricating oil subject to deterioration, from about 0.1% to 2.0% by weight of a metal allnvl carboxylate having an allryl hydroxy substituentno more than about three carbon atoms removed from a carbonyl group of the metal carboxylate. and from about 0.1% to 5% by weight of an oil soluble metal phenate.

12. A composition comprising a hydrocarbon lubricating oil subject to deterioration, from about. 0.1% to 2.0% by weight of a metal aliryl carboxylate having an alkyl hydrony substituent no more than about three carbon atoms removed.

from a carbonyl group of the metal carboirylate, and from about 0.05% to 2.0% by weight of an alkyl thio ether.

13. A composition comprising a hydrocarbon lubricating oil subject to deterioration, from about 0.1% to 2.0% by weight oi a metal alley]. carbo ylate having an allLvl hydroxy substituent no more than about three carbon atoms removed from a carbonyl group of the metal carboirylate, and from about 0.05% to 2.0% by weight of a polyvalent metal salt of an acid of phosphorus containing an organic substituent.

14. A composition comprising a major proportion oi a hydrocarbon lubricating oil and from about 0.1% .to 2.0% by weight of a metal salt of an alkyl carboxylic acid characterized by the presence of the group I moms-coon allryl group of no more than three carbon atoms,

said acid containing at least ten carbon atoms.

15. A composition comprising a major proportion of a hydrocarbon lubricating oil and from about 0.1% to 2.0% by weight of a polyvalent metal salt of an alkyl carboxylic acid characterized by the presence or the group R(OH) B-COOIf where R is a radical oialkyl structure, B is an a hydrocarbon oil and a small amount of a metal alml monocarbomlate sumcient substantially to inhibit said deterioration, said carbomlate being a polyvalent metal salt oi an acid characterized by the presence of the group 10. A compounded lubricant subject to deterioration at elevated temperatures comprising I by the presence or the group and-.. a' i allryl' group of no more than three carbon atoms, said acid containing at least ten carbon atoms.

16. A compounding agent for lubricating oils which is miscible with hydrocarbon lubricating oii'and adapted to be diluted therewith comprising a concentrated solution in anorganic solvent of a polyvalent metal monocarboxylate having an. alkyl hydroxy group no more than about three carbon atoms from a carbonyl group of the carcarbowlate.

BRUCE B. FARRINGTON.

Him 0. CLAYTON. DORE H. mm.