US2802787A - Methylene ether esters as synthetic lubricants - Google Patents

Description

eating compositions having outstanding lubricating properties atboth high and low temperatures and which have the advantage of leaving substantially no combustion chamber deposits inthe cylinders of reciprocating engines.

More particularly the invention relates to new and imtied SWSPe m proved synthetic lubricatin'gfoils which comprise methylene ether esters which have the general formula:

R(OCH2OOCR) where x is a number having a value of 1 ormoreand R and R are hydrocarbon radicals, R-preferably derived from a monohydriclor dihydric compound. a

In recent efforts to obtain superiorlubri-cating compositions which have unusual and specific properties, there have been developedentirely new synthetic materials with lubricating properties. In general these new synthetic lubricants are characterized by viscosity properties that are outstanding at both high and low temperatures, especially when compared to mineral oils. These outstanding low and high temperature properties are especially desirable for use in equipment designed to operate-over a great temperature differential, such as jet engines for aircraft use, combustion engines for aircraft, and the like. It has been found that mineral lubricating oils are generally undesirable for'the lubrication of these engines because of their high and low temperature viscosity limitations.

It has also been found that synthetic lubricants may be desirable for the lubricating of standard automotive engines. In addition to the versatility of their viscosities, the use of some types of the synthetic lubricants investigated have been found to result in very low rates of combustion chamber deposit formation, particularly When used for long periods of time. Low rates of formation of combustion chamber deposits result in increased power factor from fuel, less increase in the octane requirement of the engine, less pre-ignition tendency, and a general overall improvement in engine operation. Also, these lubricants may serve to reduce or remove combustion chamber deposits from an engine already heavily loaded with such deposits.

The present invention relates to a 'newtype of synthetic lubricating composition which comprises methylene ether esters prepared from a wide range of organic compounds which contain at least one free hydroxyl group which is alcoholic in nature. These methylene ether esters may be depicted by the formula:

In the formula R and R represent the radicals of organic compounds. These radicals may be alike or different and may contain from 1 to 60 carbon atoms. R and R are selected such that the total number of carbon atoms in the compound of this invention is between about and 130, with compounds containingifrom about to 100 carbon atoms being preferred. In the formula x has the value of one to four with values of l to 2 being preferred. The organic hydroxy compounds which serve as a source for the radicals R and R will be defined more in detail below.

For use in reciprocating engines, particularly as a lu bricant for automotive engines, a lubricating composi- 2,892,787 Patented Aug. 13, 1957 2 tion must meet several requirements. In order to form an effective lubricating film and to maintain that film at low and high temperatures it must have certain viscosity characteristics. At low temperaturesthe lubricant must be sufficiently labile to flow through the circulatory system of the equipment and allow movement of lubricated surfaces without an undue power requirement. A lubricant having an ASTM pour point belowabout +35 ice F. has sufficient low temperature liability to make it satis- I factory in these respects for general use. At high temperatures a lubricant must have sufiicient body or 'thickness to furnish and maintain a satisfactory lubricating, film. It has been foundlthat alubricant that is satisfactory in this respect will have a viscosity at 210 F. of between about 2 and 60 centistokes or-about 32 and 280 Saybolt Seconds Universal. To prevent undue lubricant loss due to volatility and to insure against explosion-hazards at high temperatures sometimes encountered, a lubricating composition should have a flash point in excess of about 300 F. These requisites are inherent in the term lubricating compositions, as used'in this specification, and the methylene ether esters of this invention are limited to those within these operable ranges; In general the preferred materials, as contemplated herein and as described in the preferred embodiment hereof, will have an ASTM pour point below about 15 F., a flash point above about 375 F., and will have a viscosity within the range of 2,6 to 13 centistokes or 35 to 7O Saybolt Seconds Universal at 210 F.

In general it has been found that the above listed properties are a function both of molecular structure and of molecular weight. This fact makes it possible, within certain limits, to prepare compositions having similar low and high temperature properties in a variety of ways and also enables the manufacturer to tailer'a composition to fit a certain set of specifications Within rather general limits. The large number of organic materials available for preparing the compositions-ofthis invention make it possible to prepare a wide range of lubricants.

R is preferably derived from an organic hydroxy compound containing at least one free hydroxyl group which is alcoholic in character. The compounds may be selected from the following partial list. Others, of course, may be used.

I. Unsubstituted alcohols:

A. Monohydric 1. Aliphatic (a; Methyl alcohol (b Ethyl alcohol (c) Propyl alcohol (d) Iso-propyl alcohol (e) n-Butyl alcohol (7) Iso-butyl alcohol (g) Sec.-butyl alcohol (It) Tert.-butyl alcohol (2) n-Amyl alcohol (9') Iso-amyl alcohol (k) n-Hexyl alcohol (I) Iso-hexyl alcohol (111) Z-ethyl-l-butanol (1t; 2ethyl-1-hexanol (o Octyl alcohol (1;) Iso-octyl alcohol (q) 2-octyl alcohol (r; Iso-nonyl alcohol (8 Decyl alcohol (t) Lauryl alcohol (u) 2-butyl-1-octanol (v) Tetradecyl alcohol (to) Pentadecyl alcohol (at) Octadecyl alcohol (1!) Allyl alcohol (2) Crotyl alcohol (aa) Oleyl alcohol (bb) The terplneols (cc) C3 to C20 oxo alcohols (dd) Alcohols derived from the Synol process (ee) Altcohols derived from the oxidation ofv petroleum fracions (17) Alcohols derived from Guerbet's reaction (gg) Alcohols derived fromthe hydration of olefins (hit) Alcohols derived from the oxyl synthesis (11) Mixtures of the above (jj) Mercaptans '(klt) Glycol monothioethers 2. Aromatic (a) Benzyl alcohol ((2) Phenethyl alcohol (1:) 3-phenyl-1-propanol (d) a-Naphthyl carbinol (e) Cinnamyl alcohol (I) Diphenyl carbinol (g) Furfuryl alcohol (h) Oumic alcohol (1') Vanillyl alcohol (7') Piperonyl alcohol B..Polyhydric 1. G cols y (a) Ethylene glycol (b) 1,2-propaned1ol (c) 1,3-propanedio1 (d) l,3butanediol (e) l,4-butanedio1 (j) 1,5-pentanediol (g) The various polyalkylene glycols, e. g.

(1) Polyethylene glycols a) Diethylene glycol (b) Triethylcne glycol (c) Tetraethylcne glycol (2) Polypropylene glycols (a) Dipropylene glycol (12) Tripropylene glycol (h) 1,2-cyclohexanoldiol (2) Decanediol-1,10 (j) Sulfur glycols (1) Dithioglycol (2) Thiodiglycol (3) Mercaptoethanol (4) Dithiodiglycol 2. Other Polyhydric Alcohols (a) Glycerol (b) Pentaerythritol (c) Z-hydroxymethyl-Z-methyl-propanediol-l,3 (d) Sorbitol (e) Dipentaerythrltol (f) Dulcitol (a) Trimethylol propane (h) Tetrarnethylol cyclohexanol (2) Benzotrimethylol II. Substituted alcohols:

A. Monohydric 1. Aliphatic (a) Halogenated Alcohols (1) Ethylene chlorohydrin (2) Trifluoro ethanol 4 (3) Propylene chlorohydnn (4) The variou s chloro-substituted monoethers of polyalkylene glycols (b) Ethanolamine (c) 2-amino propanol (d) Z-nitroethanol (e) 2-nitropropano1 (f) 2-nitrobutanol (g) The various glycol monoesters, e. g. (1) Ethylene glycol monoacetate (2) Propylene glycol monobutyrate (3) Butylene glycol monolaurate (4) Polyethylene glycol monoesters (5) Polypropylene glycol monoesters (6) Polybutylene glycol monoesters The various glycol monoethers, e. g. (1) Ethylene glycol mono-methyl ether (2) Propylene glycol mono-butyl ether (3) Butylene glycol monlauryl ether (4) Polyethylene glycol monoethers Polypropylene glycol moncethers (6) Polybutylene glycol monoethers (7) Polytrimethylene glycol monoethers (i) The various glycol mono-formals, e. g., the mixed formals of glycols and alcohols (j) Hydroxy alkyl cyanldes (l) Ethylene cyanohydrm (2) a-Hydroxy isobutyronltrlle (k) Ethanol morpholine 1ii m b 1 1 h 1 a e oxy enzy ace 0 (b) The various chlorobenzyl alcohols (c) The various nitrobenzyl alcohols (d) 2-Anllino ethanol B. Polyhydric 1. Glycols (a) Halogenated glycols, e. g.

(1) 2'chloro-1,3-propaned ol (2) 3-chloro-1,2-propanediol (b) Nitroglycols, e. g.

(1) 2-nitro-1,2-propaned1ol (2) 2-nitro-2-methyl-propanediol-l,3 (3) Trimethylol nitromethane (c) Amino glycols (1) 2-amino-L3-propanediol (2) 2-amino-2methyl-1,3-propanediol (3) Diethanol amine (4) Trimethylol aminomethane 0. Other hydrcxy compounds 1. Esters of hydroxy acids (a) The various lactate esters (b) The various glycolate esters (c) The various hydroxy stearate esters 2. Carbonyl substituted alcohols (a) Hydroxy ketones, e. g.

(1) Hydroxy acetone ((2) Hydroxy aldehydes, e. g.

(1) a-Hydroxy adipaldehyde (2) fi-Hydroxypropionaldehyde Particularly desirable organic hydroxy compounds for use in this invention are those highly branched chain aliphatic alcohols prepared by the 0x0 synthesis. This 0x0 synthesis may be described as being the catalytic reaction of an olefin with carbon monoxide and hydrogen. The reaction occurs at temperatures in the order of 300- 400 F., at pressures in the range of about 1000 to 3000 s. p. i., in the presence of a suitable catalyst, ordinarily a heavy metal carbonyl such as cobalt carbonyl. The resulting aldehyde is subsequently hydrogenated to a primary alcohol. This process is described in U. S. Patent 2,327,066 issued to Roelen in 1943.

It has been found that particularly desirable alcohols for the formation of the methylene ether esters of this invention can be prepared by the application of the 0x0 synthesis to polymers and copolymers of C3 and C4 monoolefins. These monoolefins are readily available in petroleum refinery streams and processes for their conversion toliquid copolymers have been worked out by the art. One such process, known as U. 0. P. polymerization, consists of passing the olefin-containing stream in liquid phase in contact with an acid catalyst comprising phosphoric acid impregnated on kieselguhr. Other acidic catalysts, such as phosphoric acid or copper phosphate impregnated on silica gel, sulfuric acid, Friedel-Crafts catalysts, activated clays, silica-alumina, copper pyrophosphate, etc., may be used. Suitable feed stocks, for example, may contain from 15 to 60 mol percent propylenes, from 0.5 to 15 mol percent butylenes, and from 0.1 to 10 mol percent isobutylene, the remaining being saturated hydrocarbons. Other suitable feed stocks are the dimer and trimerof isobutylene.

The preferred Oxo alcohols employed are those having from 8 to 20 carbon atoms derived from olefin copolymers having from 7 to 19 carbon atoms. In preparing these 0X0 alcohols the desired olefin fraction is segregated from the crude olefin polymer product by fractionation.

The following table, for example, shows the structure and percent composition of Ca 0X0 alcohols prepared from a C7 olefin stream which had been fractionated from the products obtained by the phosphoric acid polymerization of refinery gas streams containing propylene and mixed nand isobutylenes.

Structure of C8 Oxo Alcohols Prepared from 03-0 Percent Copolymcr Heptenes a-alkyl-alkannls 4. 3 Others 5 thesis. These alcohols are briefly described below.

5, DIMERIZAT ION OF ALCOHQLS BY GUERBET REACTION Higher molecular weight alcohols are produced from primary or secondary alcohols by an alkaline condensation known as the Guerbet reaction. This requires the presence of a methylene group adjacent to the carbinol (hydroxylated carbon) group. The sodium alcoholate of the reacting alcohol is generally used as a catalyst. However, metallic sodium has also been used, the sodium being converted to the alcoholate at the beginning of the reaction. Other alkaline agents such as sodium soaps, sodium borate, sodium allyl borate, etc. may also be used but are less satisfactory.

When relatively low concentrations of sodium alcoholate are used for the Guerbet reaction (e. g., 10 to 20 mols of alcohol per mol of alcoholate) water is eliminated according to the following equation:

The reaction is not so easily described when high concentrations of sodium alcoholate are used. Furthermore, the higher alcoholate concentrations produce higher yields of sodium salts of the acid. By use of hydrogenating catalysts such as copper, zinc, nickel, etc., however, there is a tendency to reduce the amount of salts produced while maintaining or improving the conversion to higher alcohols.

After condensation the higher alcohols and unreacted alcohols may be distilled from the reaction mixture by distillation under reduced pressure or at atmospheric pressure for relatively low molecular weight alcohols. Steam distillation may also be used. In most cases, however, it is desirable to remove the salts of the fatty acids by extraction prior to distillation of the alcohols.

Satisfactory operation conditions for condensation of a primary alcohol by the Guerbet reaction may be described as follows:

(l) Alcohol/caustic (NaOI-I) mol ratio of 10:1, in which NaOH is first converted to the alcoh-olate.

(2) Dehydrogenation agent-l gram of copper powder per mol of alcohol charged.

(3) Temperature-200-2S0 C.

(4) Time-5 to hours.

Although the above conditions are favorable for the Guerbetization of OX0 alcohols in the rangeof C8 to C13, it is possible for these conditions to be altered considerably. The Oxo alcohols or other alcohols may be condensed in the presence of an entraining agent for removing water. Pressure is desirable for alcohols boiling below the condensation temperature. The temperature and time of reaction may be varied by using diiferent concentrations of caustic.

An example of the Guerbet reaction is as follows:

Guerbetization of Ca OX0 alcohols was carried out in a one gallon nickel reactor. A large bore 30-inch condenser was attached to the reactor, which was charged with 2340 g. (18 m.) Cs Oxo alcohol 72 g. (1.8 m.) flake NaOH 18 g. copper powder This mixture was heated with agitation and little or no cooling was applied to the large condenser. Formation of the sodium alcoholate took place with the liberation of 1.8 moles of water during about one-half hour with the pot temperature at l70-l88 C. Heating and agitation were continued for 13 hours during which time the pot temperature rose to 206 C. The water from the condensation reaction was collected and the hydrogen which was liberated by the caustic fusion reaction was measured. The reaction product was removed from the reactor while still hot by the use of vacuum. It was then poured into approximately 4 liters of water while hot, thus preventing the solidification of the alcoholate or of the sodium salts. After allowing to cool, the mixture was transferred to a 12 liter separatory funnel which was equipped with an agitator. Approximately 2 liters of water and 2 liters of petroleum ether were used in the transfer. After agitation, the aqueous layer was removed and the supernatent layer (alcohols and petroleum ether) was given a second wash with 2 liters of water.

The aqueous layers from the 2 washes were combined and extracted with 1 liter of petroleum ether. Then the total aqueous portion was acidified in the presence of V2 liter of petroleum ether and the acid extract was evaporated to obtain the yield of crude acids.

The two petroleum ether extracts of the alcohols were evaporated leaving crude alcohol being a mixture of the untreated alcohol and the dimerized alcohols. This crude alcohol was then fractionated in a short path still.

P R E P A R A T I O N OF HIGHER MOLECULAR WEIGHT ALCOHOLS BY THE ALDOL CONDEN- SATION REACTION Aldehydes possessing a methylene group adjacent to the carbonyl group readily condense in the presence of alcohol and acid to yield a beta-hydroxy aldehyde which is designated as an aldol product. This product may be readily dehydrated to the unsaturated aldehyde which in turn may be hydrogenated to yield a saturated primary alcohol having twice as many carbons as the aldehyde reacted. This reaction may be described as follows:

RCHOHO $11011 E alkali ROHOHzOH H CH2R Weight Percent; Yield Materials Initial to 225 F. (C: alcohol) 225230 F. (Intermediate). Acids 330360 F. (Cw alcohol) 360-540 F. (pot) (01o glycol).-. Bottoms Trap (Mostly light hydrocarbons) As was stated above the generic formula for the synthetic lubricating compositions of this invention may be written as follows:

wherein R and R represent the radicals derived from organic compounds, x having a valueof. one or more. x may vary from 1 to 4 and is preferably '1 to 2.

When x is 2 or more R is the central portion of aglycol such as the polyalkylene glycols (i. e., mono-, di-, tri-,. tetra-, etc. ethylene, propylene, butylene, etc., glycols or mixtures thereof). R may also be derived from the various polymethylene glycols such as butanediol-l t, pentanediol-l,5, 2,3-butylene glycol, l,3-butylene glycol, 2 alkoxymethyl 2,4i-dimethylpentane-diol-l,5, hexyleneglycol, 2,4-pentanediol, decanediol-I,l0, etc. Mixtures of escapee 7 any of the various polyalkylene and polymethylene glycols mentioned above may also be utilized as the source for R.

R is the organic radical of an organic nronobasic acid. The acid used may be selected from the following partial list:

Acetic Propionic Butyric 2-ethylbutyric Caprylic 2-ethylhexanoic Caproic Pelargonic Laurie Myristic Oleic Stearic Methoxy-propionic Ethoxyethoxyacetic Mono-Cs Oxo sebacate Mono-Z-ethylhexyl adipate C3-C30 OX acids including bottoms acids Acids derived from petroleum fractions by oxidation Acids derived from alcohols and/or by alkali fusion Glycolic Lactic Hydroxystearic It is also within the concept of this invention to utilize PREPARATION OF THE METHYLENE ETHER ESTERS OF INVENTION When x in the general formula given above is 1, the methylene ether esters of the invention are prepared by either of two simple procedures:

(a) The chloromethyl ether of a monohydric compound, preferably an alcohol, is prepared by reacting the alcohol with equivalent weight of formaldehyde in the presence of hydrogen chloride at a temperature of about 30 C. to 100 C., preferably 10 C. to about 10 C. The time of the reaction will depend upon the amount of reactants used, but will ordinarily vary from about A to about 10 hours, with 1 to 8 hours being normally re quired. The chloromethyl ether of the monohydric compound may also be prepared by the chlorination of the methyl ethers of the monohydric compounds, but is preferably prepared as outlined above.

(12) The chloromethyl ether so formed is then reacted with the organic monocarboxylic acid or a metallic salt thereof.

These two reactions proceed in accordance with the following general equations:

(a) Reaction of the monohydric compound with one molar proportion of formaldehyde to prepare the hemiformal.

(b) Reaction of the hemi-formal of the monohydric compound with an organic monocarboxylic acid chloride.

These two reactions proceed in accordance with the following:

In order to more explicity define the instant invention, the following illustrative examples are given. It is to be realized, of course, that these examples are illustrative only, and are not to be considered as limiting in any way the inventive concept;

Example 1.Tridec0xymethyl stearate A 5 liter 4-necked flask which was equipped with a stirrer, a condenser, a thermometer and a hydrogen chloride inlet tube of porous glass was charged with 2,000 g. of C13 0x0 alcohol derived via the 0x0 process from a mixture of olefins containing primarily tetrapropylene, and 315 g. of trioxymethylene.

The mixture was cooled to 0 C. and then anhydrous hydrogen chloride gas was injected. The rate was adjusted so that the temperature was maintained at 5 C. to 5 C. In about 3 /2 hours all the trioxymethylene was brought into the reaction and the hydrogen chloride was evolved from the condenser. The reaction product was transferred to a separatory funnel where the aqueous layer was removed. The product was then dried with CaClz and simultaneously blown with nitrogen to remove excess hydrogen chloride gas. The crude chloromethyl ether was then filtered through Hyflo, a filter aid, and distilled in a short path still in which the fraction boiling at 99 C. to C. at 0.6 mm. of Hg (82% yield) was taken as a heart cut. Most of the chloromethyl ether distilled at 99 C. to 100 C. at 0.6 mm. of Hg.

The C13 OX0 chloromethyl ether so obtained was reacted with an equirnolar proportion of stearic acid in the following manner.

Equimolar proportions of the chloromethyl ether (124 gms.) as prepared above and stearic acid (142 gms.) were added to a round bottomed flask equipped with a stirrer, thermometer and a reflux condenser. The flask was heated, with stirring, to a temperature of about C. to C. and maintained at that temperature for about 4 hours. At the end of this period the reaction mixture was blown with nitrogen to expel evolved hydrogen chloride. The reaction product was then washed with aqueous sodium carbonate solution followed by two Water washing steps. The reaction product, so washed, was then distilled at a temperature of 245 C. at a pressure of 1 mm. Hg. 132 gms. of the product was obtained.

The product so obtained was submitted to the standard inspections with results as set out below. For comparative purposes inspection data for the C13 Oxo alcohol ester of stearic acid is included in the table.

Methylene Ether stearic Acid Ester Ester Vis. F. SUS:

210 42.1 (4. 85 Gs.) 41. 6 (4. 69 Gs.) 102. 6 (21. 2 Cs.) 98. 3 (20.2 Os.) 163 165 F +50 Flash Point, F 485 475 Combustion Test, mgs.:

Total 2. 9 8. 6 1 Varnish 1.9 6.1

1 This combustion test is conducted as follows: A five gram sample of the oil to be tested is placed in a. tared beaker and the oil is burned. After combustion is completed and the beaker cooled to room temperature, the residue is calculated by weight differential and is reported as varnish and carbon. The carbon deposit is then carefully removed from gm llnlalkecr lgay mechanical means and the remainder of varnish deposit;

ea c a e Example 2.Tride.coxymethyl pelargon'ate 9 solution was stripped to remove the, wateryand heptane and then distilled at 0.14 mm. The main fraction boiling, from 150 to 197 C. (largely at 180-190 C.) had the. following properties which may be compared with those Example 3 310 gm. ethylene glycol was condensed with 300 gms. trioxymethylene in the presence of hydrogen chloride until 365 g. hydrogen chloride had been absorbed. The condensate obtained after 5 hours at 0 to C. was purified by distillation at a temperature of 75 80 C. at 8 mm. Hg. 475 g. of distilled material obtained. This corresponds to 70% of the theoretical yield.

The bis chloromethyl compound thus obtained was treated with 2 mol equivalents of C13 Oxo acids. The acids were prepared'by the alkali fusion of C13 0x0 alcohols. The mixture was then heated at 120-135 C. until no more hydrogen chloride was given off. The reaction product was washed, dried, and finally distilled under 1 mm. pressure. The entire product distilled at 220 C.245 C., and had a zero acid number. Physical properties of the condensate are given below:

Vis./100 F 139.1 Vis./210 F 43.0 Viscosity index 113.0 Pour point F -55 Flash point F 420 Combustion test:

Car.+Var. 0.7 mg. Var. 0.5 mg.

It will be seen that the methylene ether esters of this invention have viscosity characteristics at both low and high temperatures that make them especially desirable as synthetic lubricants. It will be noted that all of the highly stripped materials listed have flash points that are desirably high and pour points which are well below 15 F.

The materials of this invention in addition to being useful as synthetic lubricants have utility in many other industrial applications. They may be used as solubilizers and plasticizers of various materials. They may also be used as bright stocks for blending with other lubricating materials whether natural or synthetic. Very useful compositions are prepared, for example, by blending the ether esters of this invention with simple monoesters and with dibasic acid esters such as esters of adipic, sebacic, glutaric, and succinic acid. They may also be blended with complex ester type synthetic lubricants such as alcoholdibasic acid-glycol-dibasic acid-alcohol, and the like. As bright stocks they may be blended with lower viscosity synthetic lubricants to obtain desired viscosity lubricants. On the other hand, the materials of this invention may be thickened to higher viscosity levels by the addition of more viscous materials such as viscosity index improvers of the fumarate ester-vinyl ester polymer, or polymerized methacrylate ester type, or other synthetic materials including high viscosity compounds of this invention.

It has also been found that lubricating compositions prepared by thickening the methylene ether esters of this invention, or blends of these with other synthetic lubricants, with grease forming soaps have desirable properties which make them especially advantageous for the lubrication of moving metal parts where a liquid cannot be used. These grease compositions are simply and economically prepared using a thickening agent of any of the common grease forming soaps, such as lithium stearate, sodium hydroxy stearate, etc.

To summarize briefly, this invention relates to new compositions of matter which have outstanding utility as synthetic lubricating oils. The materials of this invention may be broadly described as being the methylene ether esters of organic materials The structure of the materials of this invention may be described as being one corresponding to the formula:

R (OCHaOOCR' x wherein R and R are organic radicals containing from 1 to 60 carbon atoms and are derived from organic materials. R and R may be alike or different, and the total number of carbon atoms in the molecule should be be-- tween 20 and 130, preferably between 25 and 100. x has a value of 1 or more, preferably 1 to 4. The compounds that are especially preferred are those materials that have a kinematic viscosity at 210 F. within the preferred range of 2.6 to 13 centistokes, an ASTM pour point of at least as low as 15 F., and a flash point of at least 350 F. The methylene ether esters of this inven.

tion are suitable as plasticizers, solubilizers, grease bases, raw materials for detergents, extreme pressure agents, fuel oil additives, polishing agents, insecticides, fumigants, and the like. These new compositions may be blended with lubricating oils of the mineral base type, either as concentrates or as finished blends. They may be blended with other synthetic lubricants such as dibasic acid esters, complex esters, polymerized hydrocarbons, and the like. They are compatible with improving agents, such as viscosity index improvers, pour point improvers, such as polybutene, detergents, oxidation inhibitors, rust inhibitors, and the like. For instance, from about 0.5% to about 10.0% by weight of a copolymer of acrylate or methacrylate esters having an ester chain length of from 8 to 18 carbon atoms may be blended into the synthetic lubricants of this invention and the blend has a viscosity index that is considerably higher than that of the lubricant alone. This is shown by the data below:

What is claimed is: 1. A methylene ether ester useful as a synthetic lubricant which has the formula wherein R and R are organic radicals containing from 1 to 60 carbon atoms, R being derived from an organic hydroxy compound containing at least one free hydroxyl group which is alcoholic in character, R being derived from a carboxylic acid, the total number of carbon atoms in the ester molecule being between 20 and 130, and wherein x is a number having a value of l to 2, said ester having an ASTM pour point below about 35 F, a flash point above about 300 F., and a kinematic viscosity at 210 F. within the range of from 2 to 60 centistokes.

2. A methylene ether ester useful as a synthetic'lubri cant having the formula 'R(OCH2OOCR' .1:

wherein R and R are hydrocarbon radicals containing from 1 to 60 carbon atoms, R being derived from a hydroxy compound containing at least one free hydroxyl group which is alcoholic in character, R being derived from a monocarboxylic acid, the total number of carbon atoms in the ester molecule being between 20 and 130, and wherein x is a number having a value of 1 to 2, said ester having an ASTM pour point below about 35 F., a flash point above about 300 F., and a viscosity at 210 F. within the range of 2 to 60 centistokes.

3. A methylene ether ester useful as a synthetic lubri cant having the formula ROCHzOOCR wherein R is an aliphatic hydrocarbon radical having from 8 to 20 carbon atomsand R is a hydrocarbon radical having from 1 to 60 carbon atoms, R being derived from an aliphatic monohydric alcohol and R being derived from a monocarboxylic acid, the total number of carbon atoms in the ester molecule being between 20 and 130, said ester having an ASTM pour point below about 15 F., a flash point above about 350 F., and a viscosity at 210 F. within the range of 2.6 to 13 centistokes.

4. A methylene ether ester in accordance with claim,

3 wherein R is a saturated branched-chain aliphatic hydrocarbon radical.

5. A methylene ether ester useful as a synthetic lubricant having the formula wherein R and R are hydrocarbon radicals containing from 1 to 60 carbon atoms, R being derived from a glycol and R being derived from a monocarboxylic acid, the total anmbe'r'or carbon atoms in the ester mole cule being between 25 and 100, said ester having an ASTM pour point below about 15 F., a flash point above about 350 'F., and a viscosity at 210 F. within the range of 2.6 to 13 centistokes.

6. A synthetic lubricant comprising a methylene ether ester defined by claim 2 as a synthetic lubricating oil and a minor, but pour point depressing amount, of a polymeric pour point depressant.

7. A synthetic lubricant comprising a methylene ether ester defined by claim 2 as a synthetic lubricating oil and a minor, but viscosity index improving amount, of a polymeric methacrylate ester containing from aboutS to 18 carbon atoms in the ester portion thereof.

8. A synthetic lubricant having an ASTM pour point below about F., a fiashpoint above about 300 F., and a kinematic viscosity at 210 F. within the range of from 2 to centisto'kes which comprises 'tridecoxy methyl pelargonate.

9. A synthetic lubricant according to claim 8 containing from 0.5% to 10.0% by weight of a polymer of methacrylate esters containing from 8 to 18 carbon atoms in the ester portion thereof.

10. As a new compound tridecoxy methyl pelargonate.

11. As a new compound tridecoxy methyl stearate.

12. As a new compound Synthetic Lubricant Fluids from Branched-Chain Diester, I. and E. Chem, vol. 39, No. 4, April 1947, pages 484 and 486 pertinent.

Claims (1)

1. A METHYLENE ETHER ESTER USEFUL AS A SYNTHSETIC LUBRICANT WHICH HAS THE FORMULA