US2361805A - Lubricating composition - Google Patents

Description

- UNITED STATES PATENT OFFICE ruaarca'rnvc coMrosmoN Chester E. Wilson, San Pedro, CaliL, asslgnor to Union Oil Company of California, Los Angelcs, Cali!., a corporation of California No Drawing. Application April 11, 1942, Serial No. 438,649

20 Claims.

This invention relates to mineral lubricatin oils modified by the addition of constituents capable of imparting to the oils characteristics adapting them especially to severe service uses such as are encountered in Diesel engines, high output aviation engines and the like. This application is s. continuation in part of my earlier applications Ser. No. 305,496 filed November 21,

1939 and Ser. No. 345,844 filed July 16,1940.

In severe service internal combustion engines, the operating conditions tend to cause the deposition of resinous and varnish-like productsupon the pistons and around the rings to form lacquerlike coatings and deposits which tend to cause ring sticking and similar objectionable effects. In addition, there is a tendency to develop in the 011 during use conditions which are corrosive to highly corrosion-sensitive bearings of the copper-lead and cadmium-silver type.

The principle object of this invention is to produce a lubricating oil which will have suillcient detergent properties to avoid the deposition of said resinous and lacquer-like materials, whereby to overcome ring sticking, valve sticking and the like, andwhich will at the same time prevent or overcome the development of corrosive conditions in the oil during use in internal combustion engines of said severe service types whereby to avoid objectionable corrosion of bearings oi said copper-lead and cadmium-silver type.

Primarily the present invention resides in mineral lubricating oils which contain minor proportions of "oil-soluble" detergent soaps or salts, and minor proportions of "oil-soluble anti-corrosion" agents which will inhibit or control or overcome the development of conditions corrosive to said highly corrosion-sensitive bearings, said anti-corrosion agent being a condensatlon product of a phenol with an alcohol oi suiliciently high order to impart good 011- solubility to the condensation product. Said anti-corrosion agent also serves to activate or in some manner to increase materiallythe detergent properties of the detergent soap or. salt. The eflects oi the two agents used together are much greater than the additive effects oi the same two agents used separately, and the result is the practical elimination oi objectionable hearing corrosion described. The detergent soap or salt of this invention is a product of acidic materials obtained from petroleum, especially oil-soluble metal soaps or salts of synthetic acids derived from the oxidation petroleum fractions, particularly by'th'e oxidation othighly parafllnlc mineral lubricating oil fractions such as are described in the Bray Patent No. 2,270,620. Another form of detergent material may be a metal soap or salt of sulphonic acid derived from the well-known sulphuric acid treatment of mineral lubricating oil fractions such as those commonly known as mahogany acids" from which the salts are prepared. Similarly oilsoluble naphthenates may be used. v

A particular alcoholhenolic condensation product to be used as an anti-corrosion" agent is the product of condensation of steary'l alcohol with phenol in the presence of sulfuric acid as a catalyst. v

As the terms are used herein, "oil-soluble refers to a high state of colloidal dispersion of the soaps or salts in question, such that they main- .tain themselves permanently dispersed in the 'oil so as to approach a state of true solution.

The term anti-corrosion" refers to the properties of the materials to neutralize synthetic acidity developed in the lubricating oil during use, or to inhibit oxidation or catalytic activity or the like, or otherwise control conditions which would result in corrosive conditions. [The term detergent" refers to the property of an'additive either to remove deposits of resinous and kindred materials from rings and grooves of pistonand piston skirts, or to prevent such deposits, or to prevent formation and deposit in internal combustion engines.

The term viscosity index" (V. I.) is an indication of the type of oil. -A paraflin base oil is assigned the V. I. of and a certain Gulf Coast naphthenic oil has been assigned the V. I. of zero. High V. I. oils therefore are the socalled highly paraillnic" oils such as Pennsylvania oils and those highly refined with selective solvents.

1 The term soap indicates those metal salts oi high molecular weight acidic materials possess.- lng enough carbon atoms, probably at least about ten carbon atoms, per molecule to impart gooddispersibility or solubflity" in the mineral lubricating oil employed. I

In practicing the invention, the particular type 01' detergent soap mentioned as being the metal salt oi synthetic acids produced by the oxidation of mineral oil iractions may be obtained by the oxidation of said mineral oil fractions by procedures now well known. A preferable starting material is mineral lubricating oil oi the.

with or without the modern selective solvent treatment, and that obtained from Western or other mixed-base stocks containing paraflln basematerials by the more modern'highly selective solvent treatment with solvents such as phenol,

dichlorethyl ether and the like. The oxidation is carried on to yield synthetic petroleum acids which are carboxylic acids, any preferred procedure for the production of these acids being employed.

The metal salts or soaps may, be produced either by recovery of the aoidics from the oils in any known or preferred manner or form, 101- lowed by production oi the desired salt with an appropriate'base, e. g. lime to produce calcium salts, or by the neutralization of the entire" from the acid sludge containing the so-called green acids" which are oil-insoluble. The sulphonic acid salts may be produced from the oil solution of sulphonic acids either by production 'furfural, liquid sulfur dioxide-benzene mixtures.

naphthenates i'rom lubricating oil treatment as v distinguished from those from gas oil.

The anti-corrosion agent hereoi is the con- -densation product oi. phenolwith an alcohol of sufllciently high carbon content to insure that the phenolic product possesses good solubility in the oil employed. Thus, alcohols extending from about octyl alcohol or methyl cyclohexanol up through the scale including oleyi and stearyl alcohols and higher may be employed. A particular alcohol employed hasbeen stearyl alcohol. The method for the production of a phenol-' stearyl alcohol condensation product is typical of the other phenol-aliphatic alcohol condensation products. In condensing, phenol and stearyl alcohol, sulphuric acid has been employed as a catalyst to yield a compound believed to be parastearyl-phenol. The same catalyst may be used with any other alcohol indicated. In this method suitable mol proportions of the phenol and the .stearyl alcohol or other alcohol are employed or the desired salt in situ in the oil as by direct addition of the desired base, for example lime, or;

by conventional methods for recovering a sodium salt which may then be converted to other desired salts by metathesis. Again the sodium salt or such sulphonic acids is commonly obtainable on the market. However another 'form oi sul phonate may be used which is prepared by sulphonating the oil to the desired extent, and then neutralizing the entire sulphonated batch with an appropriate base whereby-green acid soaps formed are solubilized by the mahogany acid soaps with the result that both the green acid and the mahogany acid soaps go into solution in the oil to yield an'acceptable oil concentrate of mixed green andmahogany sulphonates.

Ordinarily an alkaline earth metal will be used both for the sulphonates and for the oxidation acid salts, calcium salts being usually preferred. But heavy metal salts may sometimes be used.

- especially where the respective metal salts do not rosive conditions. However where there are only with several volumes of concentrated sulphuric acid. These materials are allowed to react. The reaction temperature should be controlled in order to avoid undesired reactions which might, for'example, yield oleilns rather than the desired condensation product.

One method which has been used to produce the stearyl alcohol-phenol product follows. One hundred grams of stearyl alcohol plus 100 grams of phenol were added to 1000 grams of 80% H1504 at 180 F. with stirring. The temperature rose to 192 F. Stirring was continued for five minutes after which the mixture was poured into water and the solid material filtered oil. Shaking this withether and NaOH solution caused the slightly soluble sodium salt to crystallize out (80 grams). Forty-eight grams 01 this salt was heated with hydrochloric acid.

Naphtha was added and the mixture boiled to remove water and HCl. The naphtha solution was filtered to remove the precipitated sodium chloride, and the product was allowed to crystallize from the filtrate. The crystals were illtered oi! and washed with petroleum ether and dried. They weighed 36 grams. In order to remove any traces of strong acids the product was heated with dilute ammonium hydroxide, filtered on, and recrystallized from naphtha. This material melts at 143 F. to 146 F.

(62-63 C.) and apparently is p-octadecyl phenol.

moderate tendencies of the metal salts .to in- 1 crease corrosive conditions in any given lubricat ing oil base, these may be adequately overcome by the presence of the anti-corrosion agent added according to this invention. This appears to be true of metals oi salts oi the oxidation acids and of the sulfonic acids.

Naphthenates may sometimes be employed, and when used the soaps or salts of those metals as above indicated will be employed which produce materials adequately soluble in the particular oil composition in the proportion required.

e. g. 1% of aluminum or calcium naphthenate.-

Ordinarily the higher molecular weight acids produce soaps of greater oil-solubility, e. g.

In some instances it is satisfactory to employ this condensation product itselfas the anticorro'sion agent. In other instances it may be preferable to employ salts of this phenolic prodnot, for example the calcium salt. I

Thus, the calcium salt of the steal-y] alcoholphenol condensation product may be prepared by agitating an oil solution oi the condensation product with an equal mol proportion oi hydrated lime at suiiiciently elevated temperatures to cause reaction and formation of the desired calcium salt. Appropriate vtemperatures would bein the order of 200 F. or between aboutl'i5 F. and 225 F., for example. After reaction, the batch may be heated to around 300 I". for dehydration and then filtered or centrifuged to eliminate any solids. Apparently'the formation oi the salt may be facilitated by adding an approximately equal quantity of ethyl alcohol after I the reaction is well under way, and continuing hours. Where alcohol is thus used there appears to be less hydrolysis and the calcium content rosion agent to increase the ash content.

is increased. In removing solids and thelike, a

filter aid such as a ground diatomaceous earth may be employed. In the latter instance the batch will be heated, for example to 300 F., and filtered at that temperature while the viscosity of the liquid material is low.

In addition to lime salts or. soaps of these phenolic condensation products, the other alkaline earth metal salts may be used. For some pur- I poses it may also be satisfactory to employ salts of the heavy metals such as zinc, aluminum,

, nickel, copper, manganese, cobalt, iron, and the like. tion of the metal is that the product shall be adequately oil-soluble, and that under the existing conditions, and with the particular lubricat-.

The principal consideration in the selecing oil selected, the metal salts in the lubricating oil composition shall not act to increase the corrosion producing tendencies of the composition during use.

In selecting a lubricating oil, this may be a naphthenic base oil 01 any appropriate S. A. E. grade, or it'may be an appropriate paraflinic base oil of high viscosity index where the aderal lubricating oil fractions, will be employed in an amount approximating 1%, iorexample 1.3%. The practical limits probably will be between about 0.4% or 0.5% and 2.5% or 3%. Thesame will be true of the sulphonates, and of naphthenates. The amounts used should be such as not to increase materially the viscosity of the base oil.

With respect to the phenol-alcohol condensation product, here also the percentage may be in the order of 1%, but commonly 'a somewhat smaller proportion may be employed, for example around 0.5% to 0.7%. Here the limits probably would range from about 0.1% to 2% or 3%. Commonly larger percentages do not greatly increase the eflects derived from the materials and serve only to increase the cost, although sometimes it is found that greater proportions of the detergent salt, e. g. 2.5%, are desirable where there is no metal constituent in the anti-cor- For example, where the detergent soap might be conilned to 1.5%, it about 1% of an anti-corrosion agent is employed which contains a metal constituent, about 2.5% of the detergent salt has been satisfactorily used with an .,anti-corrosion agent containing no metal. This has been particularly true in employing sulphonates such as calcium sulphonate with a metal-free anti-corrosion agent.

In addition to the indicated straight chain alcohols to be used in preparing a phenol condensation product, I may use other saturated alcohols such as the cyclo-aliphatic alcohols with or without an aliphatic chain substituent. For example ethyl cyclo-hexanol may be used. Also I may employ the alcohols produced from naphthenic acids which are here termed naphthenyl alcohols. The naphthenes are commonly under:

stood to consist of saturated five or six-carbon.

rings substituted with aliphatic chains of greater or lesser length. In addition I may use other alcohols containing rings where the phenol condensation products, or the salts thereof, are sutficiently oil-soluble, such as benzyl alcohol.

In the above descriptions, the commonly known phenol CeHsOH has been intended. However other phenolics may be employed. Alkyl substituted phenols may be desirable where low molecular weight or polyhydroxy alcohols are used, it being the intent to include in the molecule an adequate number of carbons to insure good oil-solubility. However where substituted phenols are employed, it is necessary that not all positions be substituted, whereby to leave a'rp least one reactive hydrogen for substitution of the alcohol constituent. Other phenols may include the plural ring compounds such as naphthols, pyrogallol and the .like together with various alkyl substituted derivatives thereof as above indicated.

While the alcohols previously mentioned are monohydroxy alcohols, it is not necessary that the alcohols be so limited. Polyhydroxy alcohols may be used so long as the condensation product contains enough carbon atoms (probably at least about twelve carbons per each phenolic group) so as to render the material oil-soluble, such as glycerol or ethylene glycol. To obtain sufficient carbons such an alcohol may be condensed with an alkylatedphenol, as may any other alcohol.

Metals for salts of these various condensation products will. be those .used for other salts as above described, Salts of all the phenolics described are, in general, deemed preferable to the phenolics themselves. Lubricating oils compounded-as described will possess viscosities not substantially higher than those of the base lubricating oils employed.

Various modifications in the scope of the appended claims will be apparent to those skilled in the art. y

I claim:

1. A lubricating oil comprising a mineral lubricating oil traction, a minor proportion of oilsoluble metal soap of acids derived from 'petro-' leum, and a minor proportion of oil-soluble compound irom the condensation of a phenol with an alcohol containing at least about eight carbon atoms per molecule.

2. An oil according to claim 1 wherein the alcohol is a monohydroxy alcohol.

3. An oil according to claim 1 alcohol is a straight chain alcohol.

4. An oil according to claim 1 alcohol is a polyhydroxy alcohol.

5. An oil according to claim 1 alcohol is aromatic,

6. An oil according to claim 1' alcohol is a cyclo-aliphatic. alcohol.

7. A lubricating oil comprising a. mineral lubricating oil traction, a minor proportion of oilwherein the wherein the wherein the soluble metal soap of synthetic acids produced by wherein the 11. A. lubricating 011 comprising a mineral lubricating fraction containing a minor proportion of oil-soluble metal petroleum suli'onate and a minor proportion of oil-soluble product from the condensation of a phenol with an alcohol containing. at. least about eight carbon atoms per molecule. 4 o

12. An oil according to claim 11 wherein the alcohol is a straight chain alcohol.

13. An. oil according to claim 11 wherein the alcohol containsaring. v 14. An oil according to claim '1 wherein the compound from the condensation is a metal salt of the condensation product.

15. An 011 according to claim 1 wherein the compound from the condensation is an alkaline earth metal salt 01- the condensation product.

16; An-oil' according to claim 1 wherein the compound from the condensation is the calcium.

salt of the condensation product.

asc'nsos o 1'1. An oil acoo'rdina to claim 1 wherein the P enol is an alwlated phenol.

18. An oil according to claim 1 wherein each additive is present in the oil in an amount in the order or 1%. I

19.'An oil according to claim 1 wherein the petroleum acid salt is present in the order of a little more than 1% and the condensation com- P und is present in the order of a little less than 20. .A lubricating oil comprising a mineral lubricating traction containing a minor moportion oi oil soluble metal soap or synthetic acids obtained fromthe oxidation oi highly paramnic lubricating oil fractions and a minor proportion oi an oil soluble compound from the condensation oi phenol with an alcohol containing at least about 8 carbon atoms per molecule.

cans-ma a. wnaort.