US2929784A - Lubricating compositions containing oxime derivatives - Google Patents

Description

LUBRICATING COMPQSITIONS CONTAINING OXIME DERIVATIVES Arnold J. Morway, Clark, and Jeifrey H. Bartlett, Wes-tfield, N..l., assignors to Esso Research and Engineering Company, a corporation of Delaware Application November 1, 1955 Serial No. 544,342

11 Claims. (Cl. 25240.7)

No Drawing.

This invention relates to novel lubricating compositions having outstanding high temperature and extreme pressure characteristics. More particularly, the invention pertains to utilization of oximes in the preparation of lubricants. The invention also relates to novel metal organic compounds and to their method of preparation.

In brief, the invention pertains to compositions consisting of or containing compounds consisting of a metal salt of acetic acid, a metal salt of an intermediate molecular weight carboxylic acid or a metal soap of a high molecular weight carboxylic acid, and a metal salt of an oxime such as an aldoxime or a ketoxime. The compositions of the invention include lubricating greases, lubricating oils, gear oils, filter oils, etc.

The use of complexes as grease thickeners is well known in the art. The complexes used heretofore consisted of combinations of metal soaps of high molecular Weight carboxylic acids having from about 12 to 30 car bon atoms per molecule and metal salts of low molecular weight carboxylic acids such as acetic acid, propionic acid, etc. It has recently been suggested that such complexes may also be prepared from a combination of a low molecular weight carboxylic acid, an intermediate molecular weight carboxylic acid having from about 7 to carbon atoms per molecule and a high molecular weight carboxylic acid. Another suggestion involved the preparation of mixed salt complexes prepared from low molecular weight carboxylic acids and intermediate molecular weight carboxylic acids.

It has now been found that metal salts of oximes having the general formula C=NOH wherein R is a straight or branched chain, saturated or unsaturated, aliphatic hydrocarbon radical having from 6 to 9 carbon atoms, and R is either R or H; can be employed with acetic acid and intermediate or high molecular weight carboxylic acids to prepare complexes. The metal salts may be either used directly or prepared in situ in the manufacture of the novel complexes or lubricant compositions containing the same.

The preferred oximes for the purposes of this invention are the aldoximes corresponding to the general formula RCH=NOH wherein R is a straight or branched chain, saturated or unsaturated, aliphatic hydrocarbon radical having from about 6 to 18, preferably about 6 to 9, carbon atoms. Some of the aldoxirncs contemplated in this invention icnlude:

n-Heptanaldoxime C OX0 aldoxime n-Octanaldoxime C Oxo aldoxime n-Nonanaldoxime Cg Oxo aldoxime n-Decanaldoxime 4 plex.

2,929,184 Patented Mar. 22, 196:0

C Oxo aldoxime Dodecanaldoxime Tetradecanaldoxime Hexadecanaldoxime 0ctadecanaldoxime, etc.

Straight or branched chain saturated alkyl aldoximes-ar'e preferred in preparing the complexes and lubricating compositions of this invention.

.These aldoximes are prepared by reacting the corresponding aldehydes with hydroxylamine in accordance with the following reaction For example, C Oxo aldoxime was prepared by charging 695 grams of hydroxyl amine hydrochloride and 1200 cc. of water to a 5 liter, 4 necked flask equipped with a stirrer, condenser, thermometer and dropping funnel. Then 1024 grams of C oxo aldehyde'was added over a period of about 5 minutes at about 15 C. This was followed by the addition of 530 grams of sodium carbonate in one liter of water over a period of about 15 minutes at about 15 to 25 C. The resulting mixture was stirred for; about two hoursat a temperature of about 18 to 22 C. The crude aldoxime was then separated, water washed and distilled in a short path still using a 4" packed column. A yield of about 973 grams of C oxo aldoxime was obtained having a boiling point of 62-64 C. at 0.5 mm. pressure. Aldoxirnes and their methodsyofpreparation are described indetail in Sidgwicks Organic Chemistry of Nitrogen by Taylor and Baker, Oxford University Press (1937), pages 169 to 193. Ketoximes having the following general formula preparing the complexes and lubricating compositions of the invention. Suitable ketoximes include:

Stearophenone oxime Methyl dodecylketoxime Methyl octenyl ketoxime Stearone ketoxime Palmitone ketoxime The oxo aldehydes employed in forming the oximes are prepared by carbonylating olefins with carbon monoxide and hydrogen in the presence of a cobalt catalyst at a temperature of 300 to 400 F. and a pressure of about 2500 to 4000 p.s.i.g. The mono-olefinic carbonylation feed can comprise C to C olefins derived from cracked gases, from -Fischer-Tropseh products or from polymers of ethylene, propylene and butenes. The oxo process as well as the products obtained therein are described in detail in U.S. Patent No. 2,593,428-and Patent No. 2,695,315. The oxo aldehydes contemplated in this invention are mixtures of branched chain saturated, aliphatic aldehydes and ketones. g

In general, the amount of aldoximes and ketoximes employed in this invention will be within the range of about 1 to 10 wt. percent, preferably about 2 to '6 wt. percent,. of the total lubricating composition, or about 10 to 20 wt. percent, based on the weight of the com- The metal salts of the aldoximes and ketoximes are employed in amounts of about 2 to 15 wt. percent, preferably about 4 to 8 wt. percent, based on the tem;

lubricating composition, or about 10 to 20 wt. percent, based on the weight of the complex.

The acetic acid employed in the present invention can be either glacial acetic acid or an aqueous solution of acetic acid. When the latter is employed, the concentration of the acetic acid in the aqueous solution may vary from about 60 to 99.9 wt. percent. The presence of a metal salt of acetic acid in the metallo-organic complex is an essential element of the present invention, but the use of a substituted acetic acid having two carbon atoms per molecule is not excluded, where such modification maybe desirable. For example, chloro-acetic acid, gly- "colic acid, thioglycolic acid, glycine or oxalic acid may be used to modify the structure of lubricating compositions made in accordance with this invention. Compositions within the'scope of the invention will contain about 10 to 30 wt. percent, preferably about 7 to 20 wt. percent, based on total lubricating composition, or 25 to 75 wt. percent, based on the weight of the complex, of the acetic acid. The metalsalts of acetic acid will generally be employed in an amount within the range of about 10 to 30 wt. percent, preferably about 8 to 20 wt. percent, based on the total lubricating composition, or about 30 to 75 wt. percent, basedon the weight of the complex.

The intermediate molecular weight acids are those aliphatic monocarboxylic acids containing from about 7 to 10 carbon atoms per molecule. Either saturated or unsaturated fatty acids may be utilized, though the saturated fatty acids are preferred. Single or mixed intermediate molecular weight carboxylic acids having an average saponification value of from about 310 to 440, especially about 320 to 420, are preferred. Suitable acids include:

-methyl-2-hexanoic acid Heptanoic acid Octanoic acid 2-ethyl hexanoic acid C Oxo acid Nonanoic acid Decanoic acid C Oxo acid, etc.

The Oxo acids are those formed by oxidizing the products of the Oxo process as described above and in U.S. Patent No. 2,593,428. The intermediate molecular weight carboxylic acids will be employed in amounts within the range of about 1 to wt. percent, preferably about 2 to 6 wt. percent, based on the total lubricating composition, or about 10 to 20 wt. percent, based on the complex. The metal salts of the intermediate molecular weight acids will constitute about 2 to wt. percent, preferably about 4 to 8 wt. percent, based on the total lubricating composition, or about 10 to wt. percent, based on the complex.

High molecular weight monocarboxylic acids contain- ,ing from about 12 to 30, preferably from about 18 to 22. carbon atoms per molecule are useful for the purposes of :this invention. These acids may be derived from saturated or unsaturated naturally occurring or synthetic fatty material. The fatty acids normally used in the manufacture of conventional greases are preferred, particularly the more saturated acids. Examples of such acids include lauric, myristic, palmitic, stearic, monoand polyhydroxy stearic and arachidic acids as well as hydrogenated fish oil and tallow acids, which comprise acids corre sponding to commercial stearic acid in degree of saturation. However, unsaturated fatty acids such as, oleic, ricinoleic and similar acids may also be used. The compositions of this invention will contain about 1 to 10 wt. percent, preferably about 4 to 8 wt. percent, based on the total lubricating composition, or about 4 to 8 wt. pcrcent, based on the weight of the complex, of high molecular weight carboxylic acids. Metal salts of these acids vare generally in amounts of about 4 to 15 wt. percent, preferably 5 to 10 wt. percent, based on the total lubri 'cating composition, or about 10 to 30 wt. percent, based on theweight of the complex.

The metal component of the complexes of the invention is employed in a form which can combine chemically with carboxylic acids and oximes to form salts or soaps. Ordinarily, the metal hydroxide is used. The choice of metal component depends to a certain extent on the use to which the multiple salt and soap complex of the invention is to be put. In general, the alkaline earth metals: calcium, barium, magnesium and strontium; and the alkali metals: sodium, potassium and lithium are employed in the form of hydroxides or carbonates. Calcium hydroxide is especially preferred.

In accordance with one feature of the present invention, the complexes described above may be incorporated in a wide variety of liquid and semi-liquid materials of natural or synthetic origin. In one particular embodiment, these high metal content complexes are incorporated in mineral and/or synthetic lubricating oils in grease-making proportions of from about 5 to wt. percent, preferably from about 10 to 30 wt. percent, to produce lubricating compositions having excellent high temperature and extreme pressure characteristics as well as other desirable grease characteristics. In general, the mineral or synthetic lubricating oil should have a viscos: ity within the range of about 50 to 2000 S.U.S. at 100 F. and about 30 to 150 S.U.S. at 210 R, an ASTM pour point of about +20 to 75 F., a flash point of about 350 to 650 F., and a viscosity index of about 0 to 60. although lubricating oils having a viscosity index of 100 or higher can also be employed. As mentioned above, synthetic as well as minerallubricating oils can be employed as part or all of the lubricant base.- Synthetic lubricating oils of the hydrocarbon, hydrocarbon polymer, diester, complex ester, formal, mercaptal, polyalkylene oxide, silicone and similar types can be effectively utilized. Some of the preferred synthetic oils include di-2-ethylhexyl sebacate, di-C Oxo azelate and complex esters prepared from glycols, di-

carboxylic acids and monohydric alcohols or monocarboxylic acids.

In addition to the above constituents, the lubricating compositions of the invention may contain any of the conventional lubricating oil or lubricating grease additives well known to the art. The usual proportions of the additives are employed, and examples of such additives include oxidation inhibitors, metal deactivators, corrosion inhibitors, extreme pressure agents, tackiness or stringiness agents, etc.

The metallo-organic complexes of the invention may be prepared by coneutralization of a mixture of the acetic acid, the oxime, and the intermediate or high molecular weight carboxylic acids with suitable bases. The mixture of coneutralized material is then heated to a complex forming temperature of about 350 to 550 F., preferably about 400 to 500 F. The coneutralization step may be carried out in situ in the liquid menstruum to which the complex is to be applied in actual use. For example, the materials may be coneutralized in a portion or all of the lubricating oil which then forms the dis persant of the metallo-organic complex.

The coneutralization method of preparation is not necessary as long as the metal salts and soaps are present when heating to the complex forming temperature. Thus, the complexes of the invention may also be prepared by separately preforming at least a portion of the acetic acid salt, the oxime salt and either. the high molecular weight carboxylic acid soap or the intermediate molecular weight salt, intimately mixing the preformed materials and then heating the resulting mixture under complex forming conditions.

The complexes of the invention when prepared in a liquid dispersant may beisolated from their dispersion by solvent extraction of the dispersing medium in a solvent, in which the complexes are insoluble. Suitable solvents include most of the hydrocarbon solvents, acetone, etc.; the proper choiceidepending on the solubility characteristics of the liquid menstruum used to disperse the complexes.

In general, lubricating compositions containing the metallo-organic complexes of the invention are prepared by intimately mixing together the desired amount of mineral and/or synthetic lubricating oil and the lime, then adding a blend of the acetic acid and the intermediate molecular weight carboxylic acid to the above mixture with continued stirring. When high molecular weight fatty acids are employed, they are added separately and prior to the acetic acid. Immediately following the addition of the acids, the oxime, eg. aldoxime, is charged to the grease kettle. The grease mixture is then heated to a temperature of about 400 to 500 F. for about /2 to 1 hour. At this time, heating is discontinued, and the grease batch is cooled to a temperature of about 200 to 250 F. Conventional additives may then be added. The resulting grease is further cooled to about 150 to 180 F., and it is then homogenized in a Gaulin homogenizer, Morehouse mill or in any one of the conventional homogenizers suitable for this purpose.

The invention will be more fully understood by reference to the following specific examples illustrating various modifications oi?v the invention.

EXAMPLE I A lubricating grease composition according to this invention was prepared from the following constituents:

Formulation Percent Weight Glacial acetic acid 12. Commercial capric acid 1 3. 0 Ca 0x0 aldoxime 3L 0 Hydrated lime 10. 0 Phenyl alpha-naphthylarnine 0. 5 Mineral lubricating oil, 55 SUS 210 F- 71. 5

1 Composition:

Caprylie acid, 24.5%. Sap. No. 327. Gapric acid, 57.8%. Laurie acid, 17.6%.

Preparation EXAMPLE II Another lubricating grease was prepared from the following constituents:

Formulation Percent Weight Glacial acetic aeid 12.0 Hydrogenated fish oil acids 1 4. 0 Ca 0x0 aldoxime 2.0 Hydrated lim 9. 1 Ph enyl alpha-naphthylamine 0. 5 Mineral lubricating oil 72. 4

1 Corresponding to stearic acid in degree of saturation.

Preparation The same as set forth in Example I, except that hydrogenated fish oil acid was employed in place of the commercial capric acid. The hydrogenated fish oil was also added separately, just prior to the addition of the acetic acid.

The lubricating grease compositions of. Examples. i and II have the properties tabulated below:

Almen Test Gradual Loading Shock Loading Timkeu Test (40 lbs. load) Lubrication Lite Hours, 250 F.10,000

rpm. 4 Ball Wear Test Scar Diameter mm. 19,2;00 r.p.m.10 kg. Load-75 0., 1

15 wgts. carried, Ex. Pin.

Coud

1'5 wgts. carried, Ex. Pin.

Cond. Passed, narrow sear The above data shows that these greases'have excellent extreme pressure properties, water resistance,- high dropping points as well as other desirable grease char acteristics. When high percentages of the C Oxo ald oxime were employed in combination with aceticacid and intermediate molecular weightc'arboxylic acids as in Example I, the resulting lubricant showed thixotropic properties and tended tobe more solid with increasing temperatures. Such a product is obviously very easy to" disperse, and this feature constitutes a definite advantage for lubricant compositions encompassed by the invention. Thus, by employing the oximes described above, lubricant compositions having high metal contents without undue thickening or hardening efiects can be prepared.

It will be understood further that the invention isnot necessarily limited to the specific materials and conditions of the foregoing examples. These materials and conditions may be varied within the limits indicated in the general portions of the specification.

What is claimed is:

l. A lubricating composition comprising a major proportion of a lubricating oil and about 5 to 40 wt. percent of a complex consisting essentially of about 30 to 75 wt. percent of a metal salt of acetic acid, about 10 to 20 wt. percent a metal salt of an aldoxime having the general formula RCH=NOH wherein R is an aliphatic hydrocarbon radical having from 6 to 9 carbon atoms, and the remainder of said complex being a material selected from the group consisting of a metal salt of intermediate molecular Weight carboxylic acids having from 7 to 10 carbon atoms per molecule and a metal soap of high molecular weight carboxylic acids having from 12 to 30 carbon atoms per molecule, said metal being selectedfrom the group con sisting of alkali and alkaline earth metals.

2. The lubricating composition of claim 1 wherein said material is an intermediate molecular weight acid having from 7 to 10 carbon atoms per molecule.

3. The lubricating composition of claim 1 wherein said material is a high molecular weight carboxylic acid having from 12 to 30 carbon atoms per molecule.

4. The lubricating composition of claim 1 wherein said metal constituents are calcium.

5. A lubricating composition comprising a major amount of a lubricating oil and about 10 to 40 wt. per, cent of a calcium-organic complex prepared by concutralizing with a calcium base from about 8 to 20 wt. per- 7 cent of acetioacid, about 3 to 8 wt. percent of an aldoxime having the general formula Y RCH=NOH whereinR i s an alkyl g roup having from about 6 to 9 carbon atoms, and about 3 to 8 wt. percent of an intermediate molecular weight carboxylic acid having from 7 to, 10 carbon atoms per molecule.

6. The lubricating composition of claim 5 wherein said lubricating oil is a mineral lubricating oil.

7. The lubricating composition of claim 5 wherein said alkyl group is a branchedchain alkyl group having about 8 carbon atoms.

8. A lubricating grease composition comprising a major-amount of a lubricating oil thickened to grease consistency with a calcium-organic complex prepared by coneutralization with calcium hydroxide of about 8 to 20wt. percent of acetic acid, about 3 to 8 wt. percent of an aldoxime having the general formula RCH=NOH wherein R is an alkyl group having from about 6 to carbon atoms, and about 5 to 10 wt. percent of a high molecular weight carboxylic acid having from 12 to 30 carbon atoms per molecule.

9. The method of preparing a lubricating composition comprising a major proportion of a lubricating oil and about 10 to 40 wt. percent of metal-containing thickener, which comprises forming a mixture of a metal hydroxide selected from the group consisting of alkali and alkaline earth metal hydroxides and' a lubricating oil, adding to said mixture about 8 to 20 wt. percent of acetic acid, about. 3 to 8 wt. percent of an intermediate molecular. weight carboxylic acid having about7 to 10 carbon atoms per-molecule, then adding 3 to 8 wt. percent of an .aldoxime having the formula RCH=NOH wherein R is an alkyl group having from 6 to 9 carbon atoms, heating said mixture to a temperature of from 8 about'400" to 500 F., and then cooling to obtain said lubricating composition, wherein the amount of said metal hydroxide is sufficient to neutralize said acids and said aldoxirne. 10. The method of claim 9, wherein said lubricating oil is mineral lubricating oil and wherein said metal hydroxide is calcium hydroxide.

11. The method of preparing a lubricating grease composition comprising' a major amount of lubricating oil thickened to a grease consistency with a metal-containing thickener which comprises forming a mixture of metal hydroxide selected from the group consisting of alkali and alkaline earth metal hydroxides and a lubricating oil, adding to said mixture about 8 to 20 Wt. percent of acetic acid, about 5 to 10 Wt. percent of a high molec ular weight carboxylic acid containing 12 to 30 carbon atoms per molecule, then adding 3 to 8 wt. percent of analdoxime having the formula RCH=NOH wherein R is an alkyl group having from about 6 to 9 carbon atoms, to the resulting mixture, heating to a temperature of about 400 to 500 F., and then cooling toobtain said lubricating composition, wherein the amount of said metal hydroxide is sufiicient to neutralize said acids and said aldoxime. I

References Cited in the file of this patent Boner-Reinhold Pub. Corp. (1954), N.Y., p. 624.

Claims (1)

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A LUBRICATING OIL AND ABOUT 5 TO 40 WT. PERCENT OF A COMPLEX CONSISTING ESSENTIALLY OF ABOUT 30 TO 75 WT. PERCENT OF A METAL SALT OF ACETIC ACID, ABOUT 10 TO 20 WT. PERCENT A METAL SALT OF AN ALDOXIME HAVING THE GENERAL FORMULA