US2320228A - Lubricant - Google Patents

Description

Patented May 25, 1943 Delton R. Frey, East Cleveland,,.0hio, assignor to The Lubri-Zol Corporation, Wickliife, Ohio, a

' corporation of Ohio No Drawing. Application July 18, 1940,

v Serial No. 346,219

14 Claims.

This invention relates as indicated to lubricating compositions and more particularly to lubrieating compositions which are designed for use as crank case lubricants, and especiallywhere high temperatures and conditions otherwise severe are encountered.

It has been recognized for quite some time that the properties of a lubricating composition for use in internal combustion engines, such as for example the Diesel type, may be improved bythe addition thereto otminor amounts of certain types of metallo organic compounds since the same have a .detergent'efiect in keeping down the deposit of sludge and the like which ordinarily builds up in places such as behind the piston rings and otherwise interferes with the proper operation ofthe engine.

It has also been recognized that aromatic compounds are generally preferred as addition agents and consequently many of the commercially successful addition agents for lubricants of this character have been of the aromatic type. The desirability of using an aryl metal oxide, i. e., an aromatic compound in which the oxygen of the metallic oxide group is directly attached to the eral lubricating oilbasc of minor amounts of aromatic nucleus, has also been recognized.

Such compounds, unless further modified, however, are only very slightly, if at all, oil-soluble. It becomes necessary, therefore, to modify such aryl metal oxides in some way so that they may be dissolved in the mineral oil.

Reiif in U. S. Patent No. 2,197,833 modified these aryl metal oxides by replacing one or more of the nuclear hydrogens with a hydrocarbon side chain, i. e., Reiff suggested alkylation of these compounds for the purpose of rendering them oil-soluble.

The compounds proposed by Reiff are, however,

overt-hose available in the prior art, but which may b manufactured at a relatively low cost.

Other objects of this invention will appear as the description proceeds.

discovery that an improved lubricating composition may be prepared by the addition to a minoil-soluble metal oxides of aromatic esters which oxides are of the type in which theyoxygen of the metal oxide group is directly attached to an aromatic ring.

While it is believed that the foregoing definition of the broad class of addition agents whose use is contemplated by the present invention is thus accurately defined, nevertheless, for a more specific identification of the particular compounds which are representatives of such class, reference may desirably be had to the mode of preparation of the same, since, in this way, the

particular type of compound can perhaps be more accurately identified than in any other way. A specific example will first be given, and then an indication will be given of the similar materials which may be prepared in the same way.

Such specific example may be-referred to as magnesium lauryl salicylate, although it is preferred to identify the same as the organic mag-- nesium oxide obtained by replacing the hydroxyl hydrogenof lauryl salicylate with magnesium. This specific example may be prepared in the following manner:

The first step in the preparation of the material is to prepare the ester, i. e., lauryl salicylate. This method in general consists of refluxing a a slight excess of lauryl alcohol with salicylic acid To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and-particularly pointed out in the claims, the following description setting. forth in detail certain illust at ve embo iments of the invention, these being indicative, however, of but a few of the various ways in which theprinciple of the inusing xylene, for example, as a water carrier.

The material was refluxed for about twenty hours, after which it was made neutral to phenol.- phthalein with dilute caustic, and washed free of soap with warm water. The excess alcohol and solvent were then removed by vacuum distillation. Final traces of alcohol, solvent and moisture are removed by heating to 250 C. under a vacuum of about 28". An oil bath was used as a heating medium. The following table gives precise values for the various factors of the reaction: a

Table I Weight of alcohol recovered (gms) None Moles alcohol recovered None Weight of acid recovered (in H20 sol.

as salt) 52 gms. Moles acid recovered .4 Weight of NaOH used in neutralizatiom 14 gms. Co. of aqueous caustic us'ed 800 Co. of H20 used in washing (in 3 equal portions) 2,400 Time of reflux in hours 20 Temp. of reflux, C.:

Bath temperature 1'75 Vapor temperature 145 After the ester is thus prepared, the metallic derivative of the same may be prepared by reacting the ester in an alcohol solution with the necessary amount of metal. When the material identified for purposes of convenience as magnesium lauryi salicylate was prepared, the following procedure was employed:

One mole of magnesium was reacted with 2 moles of lauryl salicylate in a flask equipped with a reflux condenser and a mechanical stirrer. The flask was heated on a water bath. Two moles of the ester were dissolved in an equal volume of 99.95% methyl alcohol and magnesium turnings added. The reflux condenser was then attached and the water bath heated to 80 C.- the reaction mixture refluxed at about 70 C. The magnesium all dissolved after refluxing for 2% hours. The refluxing was continued for 2 /2 hours after the solution of the magnesium was completed. The reflux condenser was then; re-' moved and the alcohol distilled oil at atmospheric temperature. The residue was dissolved in twice its weight ofbenzene and filtered through paper to remove a slight cloud. The benzol was removed by distillation under a vacuum of about 28".

A typical batch sheet in the production of the material thus identified as magnesium lauryl salicylate is as follows:

Table II Grams lauryl salicylate 220 Moles lauryl salicylate .72 Grams magnesium 8.7 Moles magnesium .36 Co. of 99.95% methyl alcohol 250 Cc. of benzoL. 500 Grams of product recovered 225 Time of reaction; 5 hours Temperature of reaction, "0.:

Ba h 80 Reflux 70 In addition to the foregoing description of the mode of manufacture of the material identified as magnesium lauryl salicylate, it is believed that it may be helpful to give'below the procedure followed in the preparation of two other similar metal oxides, i. e., materials which may, for convenience, be identified as calcium lauryl salicylate and magnesium iso-amyl salicylate. The following procedure was followed:

Two moles of lauryl salicylate in methyl alcohol solution are reacted with one mole of calcium. The reaction is conducted in a flask equipped with a reflux condenser and a mechanical stirrer. The laurel ester was dissolved in an equal volume of 99.95% 'methyl alcohol. To this solution was added the required amount of metallic calcium. The calcium was cut into small pieces before adding it to the solution. The reaction vessel was then placed in a water bath and heated until the reaction started. The temperature at which the reaction starts was 70 C. (the reflux temperature). The reac- ,tion is exothermic, therefore, the bath should be removed as soon as the reaction starts. If the reaction becomes too violent, the flaskrmay be immersed in a water bath until the reaction subsides. In about one hour, all of the calciumwas dissolved. At this point, the water bath was; heated to 80 C. and this temperature maintained for an additional two hours. The reflux cone denser was then removed and the .methyl alcohol distilled off at atmospheric pressure. The residue was dissolved in twice its weight of hen 201. The solution was then filtered through paper to remove theslightly cloudy appearance.

The filtrate was returned to the flask and the benzol distilled on at a pressureof 6 cm. of Hg.

' there for minutes to insure the-complete removal of the benzol.

A typical batch sheet in the production of calcium lauryl salicylate is as follows:

Table 111 Grams lauryl salicylate 100 Moles lauryl salicylate' .33 Grams calcium 6.1 Moles calcium .15

Co. of 99.95% methyl alcohol; 100

C0. of benzene 200 Grams product 98 Time of reaction .3 hours Reflux temp. of

Temperature of reaction 70 C. Bath temperature C.

In the preparation of magnesium 'iso-amyl salicylate, the same general procedure as outlined above was followed. However, the reaction between the magnesium and the. iso-amyb salicylate' is more violent than the reaction be- -tween magnesium and lauryl salicylate, therefore, the procedure used is the same as that given for the preparation of calcium lauryl salicylate, except that more .benzol is required to dissolve the product.

A typical batch sheet in the preparation of magnesium iso-amyl salicylate is given in the following table:

, Table IV Grams of iso-amyi salicylate 208 Moles of iso-amyl salicylat--. 1.00 Grams of magnesium 12 Moles of magnesium .50

Cc. of 99.95% methyl alcohoL- 300 C0. ofbenzene 400 Grams of product 215 Time of reaction 4 hours Temperature of reaction Reflux temp. of

the solution.

It will be observed that the aromatic ester of the specific examples given above fromwhich a metal oxide was then prepared was, in each instance, an ester of salicylic acid with laurylalcohol.- The present invention is not limited to this particular ester as the base for the oxide.

Any aromatic ester containing a hydroxyl group.

attached to an aromatic ring may be used.

In the preparation of the aromatic hydroxy es-v ters in which the hydroxyl group is attached to an aromatic ring, and which are then used in the preparation of the metal oxide addition agents. of the present invention, ester formingconstituaw ents from classes combined.

I and J1 given below may acids solution about n. Alcohols and phenols (A) Phenolic alcohols v Monohydroxy bcnzyl alcohols Alkiliated hydroxybenzolc acids ydroxy toiuic acids Hydroxy x lic acids 'lrimethyl ydroxybenzoic acids Amyl hydroxybenzoic acids Octyl h droxybenzoic acids Lauryl ydroxybenzoic acids Cetyl hydroxybenzoic acids Cyclo alkyl substituted hydroxybenzoic acids:

Cyclohexyl hydroxybcnzoic acids Aryl hydroxybcnzoic acids Phenyl salicylic acids Hydroxyphenyl benzoic acids Hydroxy diphenic acids (B) Other acids Saligenin (salicyl alcohol) p-Hydroxybenzyl alcohol m-Hydroxybenzyl alcohol Polyhydroxy benzyl alcohols ihydroxy benzoic alcohols Hydroxyphenyl-ethyl alcohols o-Hydroxyphenyl-ethyl alcohol Hydroxyphenyl-cyclohexanols Hydrox-yphenyl-sterols Hydroxyphenyl-octyl alcohols Hydroxyphcnyl-lauryl alcohols Hydrox henyl-oetyl alcohols Hydroxy nzoyl alcohols Hydroxybenzoyl benzyl alcohols H ydroxybenzoyl ethyl alcohol Hydroxybenzoyl lauryl alcohol Conifcryl alcohol (B) Other alcohols Aliphatic Methyl alcohol Ethyl alcohol Propyl alcohols Butyl alcohols Amyl alcohols Octyl alcohols Lauryl alcohols Cctyl alcohols Cyclo-aliphatic alcohols Cyclohexanol Methyl cyclohexancl Amy] cyclohexanol Cyciohexyl cyclohexanol Menthol 'Ierpineol Sterols Naphthcnyl alcohols 2. Aromatic Benzyl alcohol Alkylated and cyclo-alkylated benzyl alcohols (C) Phenols 1. Monohydric phenols Phenol Alk'ylated and cyclo-alkylatcd phenols Cresols Xylenols Carvacrol Thymoi Ethylphenols Propyl pllcnols Butyl p nols Amyl phenols I Octyl henols Laury henols Cetyllp cnols Cyclo ieiiyl phenols Aryl-substitutcd phenols phenyl phenols Naphthols Guaiacol 2. Polyhydric phenols ihydroxybenzcncs Catechol Resorcinol Hydroquinonc ,Alkylated and cyclo-alkylntcii ilihydroxybcnzcncs Orcinol Hexylresorcinol 'lrihydroxybenzcncs Pyrogallol Phloroglucinol Hydroxyquinol Dihydroxy diphenyls Diphenols.

Phenyl dihydroxybcnzcncs Dihydroxy naph thalcncs Naphtho-dihydroxybcnzcncs Dinaphthols Dihydroxybenzophononcs Benzoyl oatcchols Bcnzoyl resorcins Salicyl phenols Esters of dihydroxybcnzoic acid It will be observed, that in order for the ester to contain a hydroxyl group attached to an arov matic ring, the ester must be formed from either a phenolic acid and any alcohol, or from a phenolic alcohol and any acid. Thus such aromatic hydroxy esters may be prepared by combining any one of the phenolic acids of class IA above with any of the esterifying materials of class II above, or alternatively by combining any of the phenolic alcohols of class IIA above with any of the organic acids of class I above.

One type of hydroxyaromatic ester from which the addition agents of this invention may be prepared by replacing the hydroxyl hydrogen with a metal, are those esters which may be made from polyhydroxyl phenols by esterifying only part of the 'hydroxyl groups so that the final ester has at least one unesterified hydroxyl group attached to an aromatic ring. A list of polyhydrlc phenols from which esters of this type may be prepared is given above under II C2. For example, a mono ester of resorcinol may be prepared by esterifying one of the hydroxyl groups with an acid such as naphthenic, stearic, phenylstearic, and chlorphenylstearic acids, and the hydrogen of the remaining phenolic hydroxy group replaced with a metal to form one type of the addition agents of this invention.

The thio esters will also be found-to be of particular utility as the base for the metal oxide addition agent of the present invention. Such thio esters may for example be convnientiy prepared in the well-known manner by reacting a phenolic aromatic acid with a thio alcohol (for example benzyl mercaptan).'

In addition to calcium and magnesium, other metals of the alkaline earth group may be used to replace the hydroxyl hydrogen of the phenolic esters employed in the preparation of the metal oxide, the use of which in lubricants is contemplated in the present invention. In addition, metals of other groups, for example aluminum, zinc. cobalt and nickel, may also be employed, but in this case a method of preparation different from that used in the above examples is usu-. ally required. This may consist of replacing the hydroxyl hydrogen with an alkali metal and then reacting the phenate thus formed with an alcohol-soluble salt with the desired metal in alcoholic solution. Alternatively the sodium derivative of the hydroxy ester may be formed and the latter reacted with an alcohol-soluble salt of the desired metal in alcoholic solution.

In addition to the metal oxide and ester groups which characterizes the addition agents of this invention, other substituents may also advantageously be present in the compound, attached either to an aromatic ring or at some other point. These may be any of the following:

I. The halogens Fiuonne Chlorine Bromine Iodine n-bearin radicles n l gse may bi classified according to the nature of the attachment of theoxygen to the molecule, viz: (A) Directly attached to one or more carbon atoms as in the case of:

(1' The ether rsdic1e, -O (2') The hydroxyl radicle, -8II H (3) The carbonyl radicle, Q

And other redicles contairung Carbonyl, e. g.

H Aldehyde, C H

II Ester, C-O R II Monothio-ester, C-S R H Monothio-salt, GSM

(4') Radicles in which oxygen forms part of a ring 0 structure, e. g.

Furyl and hydrofuryl (5) Inorganic radicles where the Oxygen is directly attached to 21 Carbon atom, e. g.

Arsenite Hypochlonte Phosphite Thiophosphote Thl0ph0SDhlt6 B-Hydroxylamlne III. Other substitucnt groups including: 7

mine, and substituted amino Imino Sulphide Polysulphide 'lhiocyanate Thiocatbonyl Thlo'emide Dithloomide Dithlo-carboxyl (including ester and salt groups derived thereirom) It will be noted that the substituent groups re- -ferred to above include those which contain ele-- ments other than carbon, hydrogen, and oxygen. The term inorganic substltuents is used in the appended claims in defining these. Examples of such inorganic substituents given above are those which consist of or which contain the halogens, sulphur, nitrogen, phosphorus, arsenic, boron, and the metals.

The base oil in which the addition agents of the present invention may be advantageously employed may be any lubricating oil commonly used for the purposes previously defined. It is one advantage of these addition agents that they are efiective in both naphthenic and parafiinic' base oils.

The addition agents of the present invention will generally be found to give best results if employed in concentrations of from 0.05% to 10% and usually from 0.1% to 5% in highly refined mineral lubricating oils. A concentration of about 1.5% will usually be found to give best results when used in a highly refined parafiinic or naphthenic base oil, and used for the purpose of lubricating a Diesel engine. It is conceivable that. among the various materials specifically identified above from which the metal oxide addition agents of the present invention may be prepared, certain metal oxides may be prepared which are not sumciently oil-soluble. They, of course, are not intended to be included in the definition of the addition agents in the appended claims, where, it will be observed, the limitation oil-soluble is used.

Where an exceptionally high film strength oil is desired, i. e., a finished lubricant which has improved detergent as well as film strength properties, the addition agents of the present invention may be employed in conjunction with a separate extreme pressure addition agent such as a, sulphur or halogen compound, and optionally a halogen such as chlorine may be included in the addition agents themselves, so that both high detergency and high film strength may be 4 the property possessed; by the same molecule.

Throughout the foregoing description of the addition agents, the use of which in lubricants is contemplated by this invention, they have been generally referred to as metal oxides of aromatic esters with the oxygen of the metal oxide group directly attached to an aromatic ring. The class of materials which may be thus described, and of which representative examples have been given, have been prepared in such a way that it is logical to assume that in the reaction between the metal and the ester, the metal, during the ensuing reaction, replaces the hydroxyl hydrogen. No reason is apparent why the reaction does not take place as thus assumed. It is to be understood, however, that irrespective of the precise reaction which takes place in the preparation of the materials as above identified, the present invention contemplates the use of end products of the character of those which may beprepared by one of the methods described herein, irrespective of whether the reaction between the metal and the ester in the formation of the addition agent is precisely that which has been assumed. For convenience in designation, however, the terminology above given, 1. e., organic metal oxide of aromatic esters in which the oxygen of the metal oxide group is attached to an aromatic at 1200 R.'P. M. and then the speed was increased to 1600 R. P. M. The following conditions were maintained constant duringthe remainder of the test:

Coolant temperature F 345 Oil temperature F 225 Air fuel ratio 12.7:1

The engine was stopped at 30 hour periods for inspection of piston, piston skirt, piston rings, connecting rod bearings, etc. The engine was equipped with removable connecting-rod bearings consisting of lead-bronze with a steel backing. These hearings were weighed at the begin- Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the composition and method herein disclosed, pro

vided the ingredients or steps stated by any of the following claims or the equivalent of such stated ingredients or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A lubricating composition comprising a majorproportion of mineral lubricating oil and a minor proportion of an oil-soluble metal oxide of an ester of an aromatic acid with an aliphatic alcohol, which oxide is of the type in which the oxygen of the metal oxide tached to an aromatic ring.

2. A lubricating composition comprising a major proportiomof mineral lubricating oil and a minor proportion of an oil-soluble metal oxide of an ester of an aromatic acid with a long dh'ain aliphatic alcohol, which oxide is of the type in which the oxygen of the metal oxide group is directly attached to an aromatic ring.

3. A lubricating composition comprising a magroup is directly atjor proportion of mineral lubricating oil and a minor proportion of an oil-soluble metal oxide of an ester of salicylic acid, which oxide is of the type in which the oxygen of the metal oxide group is directly attached to an aromatic ring.

4. A lubricating composition comprising a major proportion of mineral lubricating oil and a minor proportion of an oil-soluble metal oxide of an ester of salicylic acid and an aliphatic alcohol, which oxide is of thetype in which the oxygen of the metal oxide group is directly attached to an aromatic ring.

5. A lubricating composition comprising a ma.- jor proportion of mineral lubricating oil and a minor proportion of an oil-soluble metal oxide of an ester of salicylic acid and lauryl alcohol which oxide is of the type in which the oxygen of the metal oxide group is directly attached to an aromatic ring.

6. A lubricating composition comprising a major proportion of mineral lubricating oil and Example No. I Example No. Ii

' e of oil N aphthenic Naphthenic M Paramnic Mg. Aggition ent No e Lfluryl Sahel/late N Lanryl salicylate, Percent ad ed. 1. LOQ Per cent ash .063. Acid number Basic 0.03. Conradson carbon. per cen o Viscosity at 210 F Viscosity at F sac:

A. P. I. gravity Flash pom Fire point- Pour point N. P. A. color 180 s Number of rings stuck at- Loss in weight of bearings, mgs. at

60 hrs 90 hrs hrs-- hrs. hrs" Not run.

a minor proportion of an oil-soluble alkalinecarth metal oxide of an ester of salicylic acid and lauryl alcohol, which oxide is of the type in which the oxygen of the metal oxide group is directly attached to an aromatic ring.

7. A lubricating composition comprising 'a major proportion of mineral lubricating oil and a aszaaae of oxygen and sulphur, and R. is selected from minor proportion of an oil-soluble organic'magnesium compound of the type which may be produced by reacting metallic magnesium with an ester of salicylic acid .in the presence of an alcohol.

8. A lubricating composition comprising a major proportion of mineral lubricating .oil and a minor proportion of the organic magnesium'oxide obtained by replacing the hydroxyl hydrogen of lauryl salicylate with magneisum.

9. A lubricating composition comprising a major proportion of mineral oil and a -minor proportion of an oil-soluble metal oxide of. an aromatic ester in which the metal oxide group is directly attached to an aromatic ring, having the general formula MO- 11- o-xw where M is a metal, R is an aromatic radical, X is selected from the class consisting of sulphur and oxygen, X is selectedirom the class consisting of oxygen and sulphur, and R is selected from the class consisting of aromatic radicals, cycloaliphatic radicals, and aliphatic radicals.

10. A lubricating composition comprising a major proportion of mineral oil and, a minor proportion of an oil-soluble meta1 oxide of an aromatic ester in which the metal oxide groupis directly attached to an aromatic ring, having the general formula MR-C-'XR X where M is a metal, R is an aromatic radical, X

is selected from the class consisting of oxygen and sulphur, X is selected from the class consisting of oxygen and sulphur, and R is selected from the class consisting of aromatic radicals, cycloaliphatic radicals, and aliphatic radicals, which organic metal omde also contains an additional inorganic substituent in at least one of the radicals of the class consisting of R and .R' in the foregoing formula. I

11. A lubricating composition comprising a major proportion of mineral oil and a minor proportion oi an'oil-soluble metal oxide of an aromatic ester in which the metal oxide group is directly attached to an aromatic ring, having the general formula is selected from the class consisting of oxygen and sulphur, X is selected from the class consisting the class consisting of aromatic radicals, cycloaliphatic radicals, and aliphatic radicals, which. organic metal oxide also contains-an inorganic substituent selected from the class consisting of sulphide and polysulphide radicals in at least one of the radicals of the class consisting of R and R in the foregoing formula.

r 12.-A lubricating composition comprising a major proportion of mineral oil and a minor pro- ;portion of an oil-soluble metal oxide of an aromatic ester in which the metal oxide group is directly attached to an aromatic ring, having the i where M is a metal, R is an aromatic radical, X I

general formula MO-R-C-XR is selected rain the class consisting of oxygemand sulphur, X is'selected from the class consisting of oxygen and sulphur, and R is selected from the class consisting of aromatic radicals, cycioaliphatic radicals, and aliphatic radicals, which organic metal oxide also contains sulphur in at least one of the radicals of the class consisting of R and R' in the foregoing formula.

13. A1. lubricating composition comprising a I major proportion of mineral oil and a minor proportion of an oil-soluble metal oxide of an arcmatic ester in which the metal oxide group is directly attached to an aromatic ring, having the general formula M0R C-XR where M is a metal, R is an aromatic radical, X is selected from the class consisting of oxygen and sulphur, X is selected from the class consisting of oxygen and sulphur, and R is selected from the class consisting of aromatic radicals, cycloaliphatic radicals, and aliphatic radica-lawhlch organic metal oxide also contains a halogen in at least one of the radicals of the class consisting of R and R in the foregoing formula.

14. A lubricating composition comprising a major proportion of mineral oil and a minor"proportion of an oil-soluble metal oxide of an aromatic ester in which the metal oxide group is directly attached to an aromatic ring, having the general formula where M is a metal, R is an aromatic radical, X

is selected from the class consisting-of oxygen and sulphur, X'Iis selected'from the class consisting of oxygen and sulphur, and R. is selected from the class consisting of aromatic radicals,

' cycloaliphaticradicals, and aliphatic radicals,

which organic metal oxide also contains chlorine,

in at least one of.the radicals of the class consisting of R and R in the foregoing forinula.

DELTON R. FRE'Y.