US2317666A - Lubrication composition - Google Patents

Description

April 1943- A. w. BURW ELL ETAL 2,317,666

LUBRICATION COMPOSITION Filed May 8, 1940 3mm IPV of the latter in liquid phase.

Patented Apr, 27, 1943 mnmroA'rroN coMrosrrIoN 1 Arthur W. Burwell and James Allan Cameltord,

Niagara Falls, N. Y., assignor to Alox Corporation, New York, N. Y., a corporation of ,ltlew York Application May s, 1946, Serial No. 334,036

- 4 Claims. 111252-39) high molecular weights) derived from mineral hydrocarbonaceous mixtures (e. g., petroleum oils and/or waxes) by the controlled partial oxidation The invention \is concerned with processes for .the production, of such thio-alkyls, with the thio-alkyls per segand with lubricating compositions containing such 1 thio-alkyls.

It is known that some highly refined lubricating oils, more particularly parafiinic oils refined by selective solvent methods of refining, tend in use to form sludge and/or to acquire corrosive properties toward, for example, bearing metals with which they are in contact. Thus, it is known that some crankcase oils, initially free from corrosive constituents, in course of use develop corrosive propertiestowards copper-lead, cadmium-silver, and other bearing alloys, and form objectionable sludge in the presence 'of some metals. In the case of relatively high-speed Diesel engines it heretofore had been considered necessary to use only babbitt at the bearing alloy,

aliphatic carboxylic acids, said mixture being obtainable by the controlled, liquid-phase, partial oxidation of a mixture of hydrocarbons of mineral origin (e. g., petroleum wax or/and oil). Said patent discloses that the described oxidation procedure yields oxygen-containing compoundsclassifiable as saponifiables (typified by free saturated aliphatic carboxylic acids, and lactones and esters thereof) and unsaponifiables (typified by alcohols, alcohol-ketones and ketones), and thatthe ,addition material may consist exclusively of the saponifiablesf portion or may be composed of saponifiables in admixture with unsaponifiables. U; S. Patent No. 2,128,523 to Arthur W Burwell discloses the prevention. oi corrosion of metal surfaces by filming them with a composition containing the aforesaid unsaponifi'ables, and his PatentNo. 2,110,078 dis closes as an oiliness agent for lubricating. Diesel engines a mixture or non-acidic, partially oxidized saturated aliphatic chain hydrocarbons of more than 5 carbonatoms each, including alcohols, alcohol-ketones, ketones, lactones and csbecause babbitt is less sensitive-than, say, copper-lead bearing alloy-to the corrosive action of the low molecular weight acids formed in the oil by oxidation of the latter in the crankcase, al d from other decomposition products.

It is an object of the present invention-to provide a thio-alkyl "additive which, when added in 7 ing alloys sensitive to corrosion.

U. s. Patent No. 1,863,004 to Arthur W. Burwell discloses improving the oiliness of crankcase oils by'the incorporation therein-of an oil-soluble addition material consisting essentially of a mix-.,

ture of high-molecular-weight aliphatic oxygencontaining compounds including free saturated ters, produced by the Burwell oxidation process.

We have found that thio-alkyl products-compatible with refined mineral lubricating oilshaving bothisludge-inhiblting and corrosion-inhibiting properties, may be produced by treating with phosphorus hepta sulphide (P487), at an elevated temperature of the order of 250 to 300 F., the oxygenated hydrocarbons mixtures produced by the process described in the aforesaid Burwell Patents Nos. 1,863,004,v 2;110,078 and 2,128,523. That is to say, we have found that these oxygenated hydrocarbonswhich heretofore had been known to inhibit corrosion and/or to enhance oilinessmay have sludging-inhibiting properties conferred upon them by reacting them with phosphorus hepta sulphide, under conditions to form thio-alkyls of the same, and

that the resulting reaction products, when freed from components soluble in Water, are trebly valuable additives for refined lubricating oils. The

said additives are, in general mixtures of a plur'ality of sulphur-containing aliphatic compounds each or relatively high molecular weight (i.- e.,

containing 6 or more carbon atoms-to the molecule); thesecompounds may be broadly designated as thio-alkyls, which term -is here employedto embrace thio-ether's, thio-esters, thio-.

' lubricant.

Determination of sludge formation at coinpletion of the Indiana test showed the following: Sample #1-199.8 mg. per gr. oil Sample #2-1ll.9 mg. per 10 gr. oil

The above test demonstrated that the thioalkvl mixture of Example 111 inhibited bearing corrosion in a bearing metal known to be very sensitive to corrosion and also materially retarded the rate of sludge formation. The neutralization value of Sample #2 at the end of the test was materially lower than that of the oil not containing the additive.

It should. be noted, in connection with the foregoing, that the thio-ketones prepared fromketones containing from about 6 to about 24 carbon atoms per molecule have a relatively high sulphur content: in general, they show very desirable stability from the standpoints of temperature and further oxidation. By further oxidation we refer to the normal oxidation of hydrocarbon oils in use in the crankcase, the progto condensation or polymerization to a cyclic trimer (representedin 3), which latter is even more stable than the thio-ketone. The trimer may be formed in one or another of a plurality of ways; e. g., when a crankcase lubricant containing an addition of the thio-ketone is subjected to the oxidizing conditions present in the crankcase during operation of the automotive engine. The trimer shares with the parent thioketone the properties of depressing sludge forma-- tion, preventing or retarding corrosion of bear-- ing-alloys, and increasing the oiliness of the ExAmPLr: IV

The starting material was a product produced by oxidizing Sharples wax, bythe Burwell process, to a saponification equivalent of between 100 andl30, subjecting a portion of the resulting oxidation mass, including both saponiflable and unsaponifiable oxygen-containing compounds, to esterification treatment with methyl alcohol through a very fine sieve, the strained material was washed with successive amounts of hot-water,

until no free phosphoric we remained in the material and the wash water was neutral to alkacid indicator paper, and the washed product was dried.

EXAMPLE V The procedure of Example IV was duplicated using, instead of the starting material described therein, the esterified product of the following:

A portion of the oxidation mass described in Example IV was treatedwith aqueous sodium hydroxide solution under conditions to insure saponification of the saponifiable constituents thereof. The resulting soaps were separated from the unsaponifiable constituents, the soseparated soaps were decomposed by treatment with a mineral acid whereby the organic acids of the soaps were freed, and the free organic acids were recovered. The recovered free organic acids were esterifled, in known manner,

with methyl alcohol, and the resulting esters were salted out in order to free them from any whereby to convert all the esterifiable com,

ponents of the mass to' methyl esters, andremoving all water-absorbing materials from the treated mass.

100 parts by weight of the starting material just described was intimately mixed with 10 parts by weight of phosphorus hepta sulphide. Theseproportions were selected because experience had shown that an excess of unreacted P487 would remain at the end of the reaction; and hence that the concentration was suitable for completion of substitution of sulphur in the starting material. The mixture was maintained at a temperature of 300 F. for 2 hours, with constant stirring.- By the end of the heating and stirring period all visible evidence of reaction had disappeared. The reaction mixture was strained residual free acid.

By the end of the two-hour treatment of the above mixture of esters with P487 all visible evidence of reaction had disappeared. The reaction mixture was then strained, neutralized by washing with dilute sodium carbonate solution,

washed with water, and dried as described in Example IV.

Indiana oxidation tests of lubricating oils containing small amounts (e. g., 1% by weight) of.

the sulphidized products of Examples IV and V demonstrated that the latter tend to inhibit corrosion of delicate bearing metals, andto retard formation of sludge, under the conditions of use of the oil in the engine crankcase. In these two connections, the'product of Example IV showed greater inhibiting action (both as to corrosion and as to sludge formation) than did the product of Example V. Moreover, friction tests demonstrated that the sulphidized products of Examples IV and V enhanced the oiliness of the oils to which they were added in small amounts.

EXAMPLE VI An oil containing the sulphidized product of Example IV was further tested,- for tangent drag, coefilcient of friction, and breakdown, as described below and with reference to the accompanying drawing, in which Fig. 1 is a graph representing breakdown characteristics of two oils;

Fig. 2 is a graph representing changes of coemcients of friction in the two oils; and Fig. 3 is a graph representing changes in tangent drag in the two oils.

The oil selected for the test was a standard lubricating oil known in the trade as Texas Ursa. 1% by weight of the sulphidized productf Example IV was incorporated in one portion of the Ursa oil to yield sample B.

was a comparison sample andconsisted of the- Sample A" Ursa oil without additive.

Breakdown tests on samples A and B The samples were tested 7 in a lubarometer equipped with bronze bearing elements; the journal speed was 500 ft./min. and the pressure was maintained constant at 1,000 lbs/sq. in. During the continuance of the test the temperature and power 'requirements'were observed at regular intervals. In each case the test was continued until the lubricating oil film between the rotating shaft and the bearings ruptured. From the beginning of the test to incipient breakdown or I Sample A at about 290 F. the power requirements of the two were closely similar. Sample A showed complete breakdown at 300 F. However, Sample B did not showincipient breakdown until a temperature of about 420 F. had been reached, with complete breakdown at 430 F.: between 290 F. and 420 F. the power requirements in the case of Sample B did not rise (with increasing temperature) but remained between 26 and 20 watts net.

' The breakdown test readings are represented in curves A and B of Fig. 1'of the accompany= ing drawing. I

Coelflcient of friction, and tangent drug, tests on Samples .4. and B calcium salts, of the free acids may be produced and the salts treated with P481) whereby to produce anti-corrosive lubricity-increasing additives for lubricating oils and anti-corrosive ingredients of greases. Thus, calcium soaps of the P481 treated free acids are valuable additives for lubri- "cating oils used .in high-speed Diesel engines:

Figs. 2 and 3 represent the determination of coefficient of friction, and tangent drag, respectively, tests of Samples A and B. For these tests, the lubarometer was .run at a journal speed of 500 it./min. and the temperature was maintainedconstant at 212 F., while' the bearing pressure was progressively increased through the range between100 and 1,000 lbs/sq. in. The observed co,v i5

eflicients of friction, by 100 pound increments in pressure, were as follows:

Pressure The tangent drag values in pounds per square It is to be understood that instead of the esteri-' their'presence in such oils inhibits the sticking of 1 the piston rings and the development of "varnish on cylinder and piston walls, and retards or limits formation of sludge in the oils. The production of calcium salts of the carboxylic acid thio-ethers above described is illustrated below:

' ExAirrLr: VII

The starting material was a product obtained by the oxidation of crude scale wax by the Burwell process.'- The total reaction product from the oxidation was utilized and consists of a mixture of carboxylic acids, alcohols, alcohol-ketones, lactones, esters and the like.

100 parts by weight of the start ng material just described was intimately mixed with 10 parts by weight of phosphorus heptasulphide. The mixture was heated to a, temperature of 300 F.

and maintained at that temperature with conj stant mechanical agitation for a period of 2 hours. .At theend of this time all visual evidence of reaction had ceased. The reaction product was then strained through a very fine mesh screen to remove solid aggregates, and thestrained materialwas washed with successive amounts of hot water until the wash water was neutral to a sen-' sitive indicator paper. s r

.The saponiflcationvalue of the starting ma- The product was then v terial was 107 mg. per gr. KOH and the saponification value of the dried reaction product was'92 mg. per gr. KOH. 100 parts by weight of this reaction product was then mixed with 412 parts of petroleum lubricating oil. 5 To this was added 8 parts by weight of calcium hydroxide which had previously been dispersed in 15 parts of water. The mixture was heated to about 205 F. and main- I tained at that temperature for about 3 hours,-

fication agent (methyl alcohol) described in Examples IV and V above there may be employed ethyl alcohol, propyl alcohol or other similar esterification agent 'for converting the esterifiable acidic bodies to alkyl esters. carbonate solution, described in Example V, we may reduce the acidity of the product (e. g., remove the phosphoric acid, which is one of the reaction products) by washing the Past-treated.

material with an aqueous solution of another mild alkali. It is to be understood, also, that thio-ether products, equivalent to that described in Exam-- ple V, may be produced by-treating a mixture of the free acids with P453? and thereafter esterifying the acidic groups of the resulting thio-ether compounds with a suitable esterifying agent (e. g., with methyl or ethyl alcohol).

Instead of sodium We; have found, also, that the'aforesaid free acids may be treated with P481 as above described and salts, e. g., calcium salts, produced Iromthe resulting acidic thio-ethers' (or, that salts, e. g...

with constant stirring. At the end of this period the temperature was gradually increased until a temperature of about 270 F. was attained; at this point all the water had been expelled. The mass was then cooled. When a small portion of this final product was thoroughly mixed with previously neutralized ethyl alcohol a very deflnite alkaline reaction was observed. Analysis of the product showed an equivalent of 1.79% CaSOl in the mass.

The resulting calcium soap concentrate, which was roughly equivalent'to a 20% concentrate of the calcium soap of the sulphidized reaction product, was readily soluble in several types of hydrocarbon lubricating oils in amounts equivalent to 10% of the -.starting oxygenated-hydrocarbon material.

A lubricating oil composition particularly de-- sirable for use as a Diesel engine lubricant con-: sists essentially of a solution of the aforesaid calcium soap concentrate. in a petroleum hydrocarbon lubricating oil !(e. g., a high viscosity index petroleum hydrocarbon lubricating oil) thecalcium soap content of which T composition amounts to from about 0.5 to about 3.0% by The mineral lubricating fraction employed in preparing such a composition may-vary from a of oils within this range, it has been demonstrated that the addition of a calcium salt of the type above described eifected substantial decreases in sludge formation and corrosion of bearing alloys.

It is to be noted, relative to the above example descriptive of a normal calcium soap of the dicarboxylic salt of an aliphatic thio-ether, which calcium soap is believed to have the formula cniwnemc inxcmmcoo S Ca I omwmncn cne hco that it is equally possible, by suitable alteration in the relative amount of calcium hydroxide employed in the reaction, for two molecules of-the di-carboxylic acid compound so to react as to form an acid salt of the type. cn3.(cn,),.. :H. cH,)....coo-c aOOC.(CHa)m.(l3H.(CHz) on;

i i CHa.(OH2)mCH.(CH2)...COOH HOOC.(CH2)..CH.(CH:)-.OH;

It is to be observed from the foregoing that the reaction with P450 may be carried out either (a) with the total oxidation mass which includes acids, alcohols, alcohol-ketones, ketones, ester and lactones or (b) with any desired fraction of the total oxidation mass which may, by suitable known manipulation, be separated therefrom.

We claim: 1. A lubricating composition consisting essentially of a lubricating oil and an oil-soluble compound having the formula CHz.(CHz)-.C.(CH2) WC 0 OX wherein n and m are whole numbers whose sumwhere m and n are whole numbers whose sum is not less than 12 and not greater than 48.

3; A lubricating composition consisting essentially of a lubricating oil and an oil soluble compound of the formula cmwmncnrcmmcoo Ca cm. cn, ..cn. cm ..coo wherein n and m are whole numbers whose sum is not less than 12 and not greater than 48.

aliphatic hydrocarbons, including alcohols, ke-

tones, and carboxylic acid compounds, derived from a petroleum hydrocarbon mixture by controlled partial oxidation thereof, said thio-alkyl compounds including compounds of the formulae wherein n and m are whole numbers whose sum is not less than 12 and not greater than 48, and

q X stands for a substituent of the group consisting of hydrogen, an alkyl radical and a metallic salt-- forming group,

. R-S-R wherein R is an alkyl radical containing from 6 to 24 carbon atoms,

R J=s R,

wherein R and R are alkyl radicals each containing from 6 to 24 carbon atoms, and

wherein R and R are alkyl radicals each con-- taining from 6 to 24 carbon atoms.

ARTHUR W. BURWELL. JAMES ALLAN CAMEIFORD.

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