CA1067479A

CA1067479A - Sulfur-containing carboxylates as ep agents

Info

Publication number: CA1067479A
Application number: CA234,800A
Authority: CA
Inventors: Bruce W. Hotten
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1974-09-05
Filing date: 1975-09-04
Publication date: 1979-12-04
Also published as: AU502805B2; JPS5152402A; AU8441175A; JPS5829839B2; IT1042253B

Abstract

ABSTRACT OF THE DISCLOSURE
SULFUR-CONTAINING CARBOXYLATES AS EP AGENTS
Compositions are provided which are sulfurized esters of olefinic mono- or dicarboxylic acids which do not contain any allylic hydrogen atoms. Synergistic mixtures of esters sulfurized with sulfur and with sulfur monochloride and sulfur dicloride are provided. Also provided are lubrica-ting oil compositions comprising (A) a major amount of an oil of lubricating viscosity, and (B) an amount effective to impart extreme-pressure lubricating properties to said oil of these sulfurized esters.

Description

\` 10~747~

Thls invention relates to sulfurized esters o~
olefinic carbox~lic acids and to lubricating oil co~positions contain~ng thesè sulfurized esters as extreme-pressure agents.
Such compositions exhibit extreme-pressure lubricating proper-ties and are useful in cutting oils and for lubricating relatively moving parts such as in power transmission assemblies, gear trains and engines, particularly internal combustion engines.
Metal-cutting oils should be light-colored for good visibility of the work piece. Pleasant, or at least mild~
odors are required for the health and comfort Or the machine operator. In addi.tion, the cutting oils must provide extreme-pressure lubrication for the work tool in order to pro~ide the longest possible tool life before resharpening or replacement.
In other lubricating applications where the operator is not exposed to vapors from the oil and visibility of the lubricated part is not crucial, color and odor of the oil may not be as important as extreme-pressure lubrication and antioxidant protection. However, odor and appearanceare important to those who must prepare the lubricating oil additives, compound the oils and handle the oils as they are being used.
The reaction products Or sulfur and olefinic compounds such as cracked wax, lard oil and sperm whale oil are dark brown or black even when diluted to the final use levels with oil. In addition, these compounds are malodorous, smelling of hydrogen sulfide and mercaptan by-products.
Previously, light-colored, mild-smelling sulfur compounds for use in cutting oils have been made by chlorination or sulfo-chlorination ~llowed by treatment with sodium polysulfide.

~06747~

This m~lti-step indixect pracess i~s expen~s~Ve and, accordingly~ the cutt~
ing oils prepared therefrom are expensive.
What is needed are light-colored, mild-smelling lubricating oil compositions which can be prepared ~rom lnexpensive materials by an ine~pensive, preferably one-step, process. mis invehtion fulfills this need rather nicely.
Smith, United States Patent 2,683,119, describes compositions for imparting oiliness and film strength to lubricating oils. The compositions have at least two esterified carboxylic acid groups and at least one sulfur atom in a thiolinkage. All of the illustrated examples of suitable acids contain allylic hydrogen atoms.
Hutichinson et al, United States Patent 3,740,333, disclose compositions useful as substitutes for sperm oil. m e compositions are blends of triglycerides and wax esters. The wax esters are derived from unsaturated fatty acids containing 18, 20 or 22 carbon atoms. m e tri-glycerides are of the same fatty acids. The blend of the wax ester and ; triglycerides is sulfurized by conventional means.
Sulfurized esters of olefinic mono- or dicarboxylic acids which do not contain any allylic hydrogen atoms have been discovered which are excellent additives for lubricating oils and metal working and cutting oils. In a preferred embodiment, mixtures of sulfurized and sulfochlorinated materials are provided, the mixtures displaying a synergistic improvement in drilling torque lowering.
According to the present inventlon there is provided a -lubricating cut~n~ or metal wo~ing oil co~,position comprising: (a) a major amount of an oil of lubricating viscosity, and (b) an amount effective to impart extreme-pressure and/or antiwear lubricating properties to said oil of a sulfurized ester of an olefinic mono- or dicarboxylic acid, said ester being free of allylic hydrogen atoms and of phosphorus.

~" .

74~79 Lubrlcating o~l co~mpositlons co:ntaining these sulfurized esters are relatlvely quite light'in eolor and are mild smelling.
Thelr sulfur content provides excellent extreme-pressure lubricating properties. In addition, almost no hydrogen sulfide is evolved during preparation o~ the sulfurized esters;
thus, an air-polluting by-product is avoided.
Compositions suitable for use as additives to lubricating oils and metal-working and eutting oils eomprise sulf'urized esters of olefinie mono- or dicarboxylie aeids whieh do not contain any all~ic hydrogen atoms.
The lubricating oil eompositions of this invention comprise (a) a major amount of an oil of lubricating viscosity, and (b) an amount effeetive to impart a benefieial effeet, such as extreme-pressure and antiwear properties to the oil of these sulf~rized esters.
The esters f~om which the sulfurized esters are prepared are esters of' olef'inic mono- or diearboxylie acids and low-to-medium molecular weight aleohols, neither of whieh eontain any allylie hydrogen atoms.
l'he Carboxylic Acids As mentioned above, the esters are prepared from mono- and dicarboxylie aeids which do not contain allylic hydrogen atoms. Examples include aeids eontaining from 3 to 200 earbon atoms. Allylie hydrogen atoms are well known to those skilled in the art. They are hydrogen atoms bonded to saturated carbon atoms whieh are alpha to a double bond. An example of this is shown in the following Formula I.

-C = C - C - H*
I

~067~79 Ih Formula I the hydrogen narked with an asterisk is an allylic hydrogen. An example of a carboxylic acid which contains no allylic hydrogens is acrylic acid (CH2=CH-COOH).
~n example of a carboxylic acid which contains allylic hydrogens is methacrylic acid (CH2=C(CH3)-COO~I). In methacyrlic acid, the methyl group bonded to the alpha carbon atom is a saturated carbon atom to w~lich are bonded hydrogen atoms. Thissaturated carbon atom is alpha to the double bond of acrylic acid; therefore, the hydrogen atoms on the methyl group are allylic hydrogen atoms.
Examples of suitable monocarboxylic acids for use in this invention include acrylic acid, 2,4-pentadienoic acid (beta-vinyl acrylic acid), 4,4-dimethylpenta-2-enoic acid and other s~milar compounds. Preferred examples of monocarboxylic acids suitable for use in this invention, including those mentioned above can be represented by the general formula II
z (c = f ~X - COOH

Z
wherein x represents 1, 2 or 3, preferably 1, and Z represents hydrogen or a hydrocarbyl radical bonded to the remainder of the carboxylic acid through a tertiary carbon atom. Examples of suitable hydrocarbyl radicals include t-butyl, t-pentyl, t-hexyl, t-octyl, t-dodecyl, t-hexadecyl~ t-octadecyl and the like ~enerally, the monocarboxylic acids will contain 30 or less carbon atoms. Preferably, not more than one Z substituent per molecule represents a hydrocarbyl radical and more preferably, all Z substituents represent hydrogen.
Suitable dicarboxylic acids include fumaric acid (trans-butendioic acid), maleic acid (cis-butenedioic acid), muconic acid (hexadiendioic acid), 2-t-butyl-fumaric acid, 2-t-butyl maleic acid, 2-t-butyl muconic acid and the like.

;747~

Preferred examples of suitc~ble dicarboxylic acids useful in thlS

inventlon~ including those mentioned above, can be represented by the ~ollowing formula:

III
HOOC - (f ~ C~x - COO~I
Z Z
wherein x and Z have the same meaning as defined above for Formula II. Generally, the dicarboxylic acids will contain 30 or less carbon atoms.
Of course, for purposes of preparing the esters to be sulfurized, the anhydrides and acid halides of the above-described mono- and dicarboxylic acids can be used, and this invention contemplates their use. The anhydrides can be simple or mixed anhydrides and include external anhydrides such as ac~ylic anhydride and intem al a~u~rides such as maleic anhydride.

The Alcohols Suitable alcohols which may be combined with the car-boxylic acids described above to ~orm the esters which are then sulfurized to form the compositions of this invention include lower- to medium-chain-length alcohols. Suikable alcohols include lower- to medium~molecular-weight aliphatic alcohols such as ~he lower- to medium-molecular-weight alkanols.
Examples include those contalning from 1-30 carbon atoms. The aliphatic portion of the alkanol may contain minor, sometimes adventitious, amounts of atoms other than carbon and hydrogen such as oxygen, halogen, nitrogen and ~lfur. Ihe aliphatic portion of the alcohols can be straight- or branched chain and may contain a sm~ll number of sites of unsaturation.
Generally, the alcohol contains not more than one olefinic site per alcohol molecule and preferably is completely saturated.

~L06t7479 If the aliphatic portion of the alcohol contains any sites of 266 unsaturation, it should not contain any allyLic hydrogens. 267 In ~eneral, suita~le alcohols useful in preparing the 268 compositions of this invention can be represen~ed by the 269 formula ~ 270 IV R-0~ 273 wherein R represents the remainder of the alcohol exçlusive of 277 the hyàroxyl group, suitably containing from 1 to 30 carbon 278 atoms, preferably contai~ning from l to 12 carbon~ atoms, and 279 more preferably containing from 4 to 8 carbon atoms. R ~280 generally is~aliphatic in nature and may c`ontain olefinic sites 281 of unsaturation as discussed above. , 282 Suitable low~ to medium-molecular weight alcohols 283 .
include methanol, ethanol,` propanol, isopropanol, butanol, 284 isobutanol, sec-butanol~, t-butanol,~pentanol, 2-ethylhexaDol, 285 octanol, decanol, hexadecanol, octadecanol, tripropylene oxo 286 alcoh~ol, tetrapropylene oxo alcohol, ethoxyethanol and the 287 1~1ke. 288 ~he EsteEs ~ ~ The esters a~re formed from the above-described car- 292 boxylic acids and the above-described alcohols. Methods of~ 295 preparing these est~ers are well known to those~skillea ln the 2~6 artO They include, for e~ample, direct combination of the acid 297 ~wmth the alcohol, sometimes using aineral acid catalysis to 299 h~sten the reaction. Water ~ay be removed to drive the 300 reaction to co~pletion. In other instances, acid halides or 3Q1 acid anhydrides can be reacted ~ith the alcohol. Preparing the 303 esters forms no part of this in~ention and need not be further 304 illustrated. ~ ~ 305 In general, suitable esters of monocarboxylic acids 306 useful in this invention can be represented by the following 307 formula ~ 308 .

~lO~i747g .
V ~) 312 Z ~ )X - C - O - ~ ~ 313 ~' .
and suitable esters of dicarboxylic~acids use~ul-in this 3i8 :~ invention can~be represented by the folloving formula~ 319 V I: ` ~ O ~ 3 2 3 R 0 C 11 - lCt X C -- O - R ~ ~324 : . Z Z . ~ 325 wherein ~, Z, and x have the same mèaning as defined~above. 330 : Pre~ajjratio~ f_th~ sulfurlz-ed-E-t-e-s ~ 332 :
~The esters:can~be sulfurized,~generall.y ~ithout 334 difficulty~,~simply;by combLnlng~the~above-describe~d ester and ~ 335 ele~enta~l sulfur,~sulfur~monocbloridé;~or sulfur ~dichloride.~ 338:
: Sulf:urization:can be conduct:ed:at any temperature:at:: 339 vhich~the reaction~takes place~below tbe~decompos~ition: ~ 3VO
temperature of the r~eactants or the:reaction proaucts.~ I:t is ~ ~3~4~ 2 generally preferable to conduct the reactio~ at an elé-ate~d ~343 temperature~to~increase the rate~of reaction. Pre~erabl~y, th~e~ 344:
r~eaction between the~sulfur and the~ester ~lS conduct~ed~bet~een~ 345:
about~lO0 and 20~C, preferab~ly 120-200C. Thls reaction is : 346 qenerally continued fro~a~bout 0.5-48.hours, more generally: 347 frbm about 2-24 hours.~ 348 The:reaction betveen the est;er and sul~ur ~ono-~ ~ 349 chloride or sulf~r dichloride typically goes easily at lower :351 temperatures than the~reaction bet~een the ester~and eleme~ntal 352 sulfur~ Typically, this reaction can~be carrled out betveen . 353 about 60 and 200C,.pre~erably between about 80 and 180C. The 355 reaction is generally continued for about 0.5-48 hours, ~ 356 pref~rably 2-36 hours. .: 357 ~747~

The mol ratio of sul~ur or sulfur c,hloride to the 3~59 ester can vary ~idely. For this purpose it is usually 360 convenient to calculate the mols of sulfur or its equivalent 361 present in the sulfur chloride used per olefinic bond present 362 in the ester. Sulfur-to-olefinic bond ratios can range from 363 0.5-2:1, preferably 0.75-1.5:1. Mol ratios Q~ approximately 365 1:1 are preferred, since this generally leads to high sulfur 366 .
content ~ithout leaving excess free sulfur in the reaction 367 product ~hich may settle out upon standing. 368 ' Most of the lower-molecular-~eight esters are liquid 369 at room temperature or at least at elevated teaction 370 temperatures. Thus, a~react~on,solvent is not-necessary. 372 Generàlly, the ester and the sulfur or~sulfur chloride are 373 simply combined in the reaction vessel and the reaction mass is 374' heat~ed to the desired temperature~with agitation. Heatin~ aod 376 agitation are continued ,through~out the~reaction period,,after 377 which the product is allo~ed to cool~to ambient temperature.~ ~ 378 after~the reactio~n product has cooled to ambient 379 temperature, it may be desirable~to allo~ it to stand from 1 to 3ao 3 days to allo~ unreacted excess sulfur to settle out. The 382 product can then be fiItered to remove this sulfur. 383 The filtered product thus obtained is generally ~ ~ 384 suitable without further purification for adding to lubricating 386 oils, ~hich may be then used to,lubricate relatively moving 387 parts and as cutting oils in metal-~ork~ng operations. 33a For esters which are not liquids at room te~perature, 389 it is generally,preferable to use a reaction solvènt~ Suitable~ 391 reaction solvent,s include any solvent with ~hich the ester is 392 miscible or in which it is soluble and ~hich does not inter~ere 393 with the sulfurization reaction. Thus, solvents which contain 394 double bonds and particularly those which contain allylic 395 hydrogens should be avoided, since this will lead,both to 396 ~Ogj74'~9 hydr~gen sulfide evolution and to ~rk-colored product~. The 398 solvents can be lower-boiling petroleum fractions ~hich may be 399 readily removed after the sulfurization reaction if the 400 reaction product is a liquid at room temperature. If the 401 reaction product is not liquid at room temperature, the solvent ~402 is generally not completely removed. In this latter case, 403 higheroboiling petroleum fractions may be desirable, ~ 404 p~articularly fractions ~hich ha~e approximately the same 405 boiling range and viscosity range as lubricating oils to which 406 the sulfurized esters may be added. The diluent oil for the 407 sulfurized ester will then simply form a suitable part of the 408 ultimate lubricating oil composition. 409 ~ hen reaction solvents are used, whether they are 410 lo~er-boiling solvents which ~ill be removed after the reaction 412 is complete or the higher-boiling petroleum fractions which are- 413 not remo~ed, it lS genérally preferable to use the least amount 41~4 of solvent possible, as this increases the concentration of the 415 reactants. Higher concentrations of the reactants ~ay not only 416 improYe the reaction rate, but also increase~reactor capacity. 417 The sulfurized esters which are obtain~ed, particu- 418 larly those made from lower-molecular-weight carboxyllc acid 420 esters such as the alkyl acrylates are liquid at room 421 tempera~ure and have a lo~ enough viscosity to allow pumping 422 and easy handling at room temperature. Purthermore, these 423 .
sulfurized esters are readily miscible~ith lubricating oils. 424 They are also much lighter in color, especially after dilution 426 in oil to normal working levels, than ordinary sulurized 427 compounds made by direct~reaction of sulfur. In addition, 428 these~ sulfur~zed esters have a mild and pleasant odor. 429 ~IQ~iiP747g .
bri-atin~-and-cuttlnq-oals 432 While the sulfurized esters of thls invention which 434 are liguid at ambient temperatures can be used neat in metal- 435 cutting and working operati~ons, it is most practical and ~437 economical to dilute the sulfurized esters with an inexpensive 439 carrier oil. ~ 44 Suitable carriers are those ~hich are suitable for' 441 use in lubricating oils and cutting oils. The sulfurized 443 esters of this invention are~present in'the lubricating oils~ 444 and ~etal~orkinq and~cuttinq oils of this invention in an 445 a~mount effective to impart extreme-pressure lubricating 446 properties to the oil~ Generally, the effective amount of 447 these sulfurized esters in the oils ranges from~about~ O.l to 448 about 20%~, pre'ferably from a~bout 0.5,to about 15~w and~more ~ 449 prèferably from a~bout l to about 10%~. In cutting oil ~ 451 applications it is~common to blend the sulfurized este,r ~ith 452 the oil~to~obtaln a specific sulfur content. For cutting oil 453 ~applications, sulfur concentrations can range from about O.l- 454 lO~, preferably about 0.5-5%~ and more preferably about455 0~5-2~. 456 , The su,lfurized e~sters can be prepared'as con^457 centrates~ They are then'blended wlth a carrier oil prior~to 459 ultimate use. Those 'sulfurized esters which are liquid at room 46 temperature are generally prepàred without a reaction solvent 462 and, accordingly, the~concentrate contains 100% of the463 sulfurized ester. Adding diluent oils to these concentrates 464 ~ould simply increase the shipping costs, generally ~ithout 465 compensating benefits such as easier handling. Those467 sulfuri%ed esters ~hich are not liguid at room temperature or ,468 ~hich are very viscous liquids at room temperat~re can be 469 prepared as highly concentrated pac~ages. Again, to keep the 471 sbipping cost to a minimum, the quantity of diluent oil in 472 these concentrate packages is kept to a minimum Generally, 474 the sul~urized ester will coMprise about 20 to about 95%w and 475 preferably is at least 50X~ of tbe concentrate`package 476 The lubricating oil compositions prepared by the 477 invention contain an oil of lubricating viscosity ~This oil 479 ; ~ should be an oil of a viscosity suitable for the purpose for 480 which the final composition is intended They are generally 481 lubricating oil fractions of petroleum, either naphthenic or 482 paraffinic base, unrefinea, acid-refined, solv~nt-refined or 483 hydrocracked as required in the particular lubricating or 484 cutting need Also, synthetic oils meeting the necessary 485 - viscosity reguire~ents, either ~ith or ~ithout viscosity index 486 ` impro`vers or other additives, ~ay be used as the base stoc~ 488 The ~iscosity of~the lubricating or cutting oil ~ill 490 ary~greatly depenaing upon the use for whlch it ia intended ~ 491 It is-~ell vithin the skill of those in the art to tqilor the ~ 493 lubricati~g oil composition to the desired specification by 494 choosing the appropriate base stoc~, mixing various base oils, 495 and/or compounding these oils or mixtures thereof with various 496 viscosity index-i-pro~ing agents com~ercialIy ava1lable. 497 ; ~ In addition to~the sulfurlzed ester described in this 499 inYention,~the oils, particularly lubricating o1ls, can contain 50~0 a variety~of other compounding agents such as dispersants, 501 detergents, extre~e-pressure agents, viscosity i~de~-improvers, 502 and other materials kno~n to be useful in compounding~ 503 luhricating oils to ~eet the various exacting specifications 504 demanded b~ the particular use to which the lubricating oil is S05 ~to be put ~ ~ 506 -For~metal-~orking operations, the lubricant~ 507 compositions of ~his invention can be applied to ~the metal 508 prior to the working operation in any suitab}e ~anner-which 509 insures thorough contact of the surface of the metal For 511 `

` :1067479 .
exa~ple, the lubricant can be brushed or sprayed on the ~etal, 512 or the metal can be immersed in a bath of the lubricant. 513 The following examples are included for further 514 .
understanding of the invention. 515 Exa~ 1 520 To a 2-liter resin flask equipped ~ith a stirrer, 522 nitrogen inlet, condenser, thermometer and an Iscarite-filled 523 gas absorption tube was added 842 grams ~4.576 mols) of 2- 525 ethylhexyl acrylate and 146 grams (4~576~mols) of elemental 526 sulfur. ~ith agitation, the reaction mass was heated to 160C 527 under a nitrogen blanket for 21 hours ~at which time the 528 reaction mass was c~oled to ambient temperature and filtered 529 through Celite 545. ~955 grams`of filtrat~e ~ere recovered ~hich 530 had~a sulfur~content of 14.0%~ 531 Exam~le_2 ~ ~ 534 `
To a l-liter~g1ass resin flask equipped as ln~Example S36 as~added 184-grams (l mol) of ;2-ethylheIyl acrylate and 32 537 gra-s (l mol) of ele~ental sulfur. ~ith agitation~, the 540 reaction ~ass ~as~heated to 160C under a nitrogen blan~et and 5~41 maintained~bet~een 160C and l70C for 14 hours.~ The reaction 543 mass~was cooleà and filtered to yield 206 gra~s of prQduct 544 ~ontaining l3.5X~ suIfur. ~ 545 ,j, . .
By a si~i1ar pracedure, sulfurized butyl acrylate was 547 prepared from butyI acrylate and elemental sulfur. The 548 .
reaction~product obtained contained 20%~sulfur. ~ 549 Si`milarly, sulfurized di-n-butyl fu~arate was 550 obtained from di-n-butyl fumarate and elemental sulfur. The 552 product contained lO.9~ sulfur. In a similar manner, di-n- 553 butyl maleate ~as reacted ~ith elemental sulfur. ~MR analysis 555 s~o~ed the maleate isomerlzed to the fumarate. 556 .
~ ~ale~ 13 -, ~,, 7479 !
~y a similar procedure, ~ellosolve acrylate (ethoxy- 557 ethyl acrylate) ~as sul~urlzed with elemental sulfur to yield a 559 product containing 17.7%w sulfur. 560 Ex_mPle_3 563 ., To a l-liter glass resin flask equipped as ln Example 565 ~ as charged 368 grams ~2 mols) of 2-ethylhexyl acrylate. 566 ,~ ~ Nlth stirring~ 135 gra=s (1 mol)~of sulfur monochloride vas~ 568 àdded from a dropping funnel over a 20-minute period. No 570 exotherm was observed. Th= reaction mass was heated with 571 ~agitation under a nitrogen blank=t to 12QC and maintained at 572 this te~perature, plus or minus 5C, for 22 hours. At the end 574 of the react~ion period the reaction mass was cooled to roo- 575 temperature and filtered with the aid of a Yacuum to yield 453 576 grams of filtrate containing 10.99%w chlorine and 7.67%w~=ulfur 577 -: , ~
~;and 27 grams of filter residue which contained 97.1~ sulfur ~ 578 and less than 0.2%~chlorine. The filter residue had l~melting 579 polnt of 113-114C. ~ ~ ~ 580;
L_~ ~ s83 S ~A. In order to in=ure that co-=ercial sulf~r ~ ~C585 ~ was pur~, a portlon o~ the ~aterial was chlorinated as follo~s ~86 " ^.
S352 g o~ com~erclal sulfur dlchlorid= erom S-auf~ec Che-icll ~S~B
Company ~as placed in a large vesse~ and cooled to 10C. 363 g 590 of chlorine wa= added to the =a;terial over a period of 3 hours, 591 while the temperature was maintained at 8-10C~ 593 B. a 20,000-g portion of 2-ethylhexyl acrylate was 594 placed in a large vessel equipped ~ith stirrinq and beating 595 means. A 5605-g poFtion of the product of "A" was added with 596 stirring over a period of 15 minutes~ Durinq thi= ti~e the ~ 598 te=perature was 23.9C~ After 15 minutes, the temperature had 600 increased to 76.7C. After an additional 13 =inutes, the 601 te~perature had increased to 111.1C a~nd after an additional 7 603 minutes had dropped to 108.9C. The mixture ~IS then heated to 604 _ 1L~ _ ~

~067479 .
about 130C and maintained at that te~parature ~ith stirring 605 for 24 hours. The mixture was then cooled to 15.6C and 606 filtered through a 3-micron cartridge-type filter. 608 The yield of material was 23,7~0 g. The product 610 contained 6.41% by ~eight sulfur and 11.2~ by weight chlorine. 612 Exampl_ 5_=_ Dr 1~ Tor~ue_Tes_ 615 The compounds prepared above ~ere ~ested ~or their 617 properties as additives for cutting oils in the Drilling Torque 618 Test. In this test a drill press ~ith variable po~er feed and 621 ~ variable speed is used. A drilling torque measuring system 623 comprised of a rotating uork piece holder, a table, a torque 624 arm, a strain gauge, a load cell, and a recorder is used. The 626 drill bits are high speed, steel, jobbers-lengt;h drills, 3/8" 627 diameter, preground to 130~cutting edge. The drilling test 628 m~a~erial is type 304 stainless steel used in 6" x 6" x l-l/2" ~629 blocks. ~ ~ 630 The torque measuring system ~is calibrated to zero an~d 631 tbe final stopping point of llO inch-pounds of torque is 632 determined. 633 A precision ground drill is securely tightened in the 635 drill press ch~ck. The drill feed rate is set at 0.0l4" per 636 revolution. The drill press is adjusted for the desired rate 637 of revolution and the~oil pump is started. The drill is 639 manually lovered until it is almost touching the test block. 640 The automatic feed is then engaged and a hole is drill~d. Rhen 642 the hole is complete, the drill bit is raised, the ~ork block 643 is rotated and a new hole is drilled. This procedure is 644 continued at the constant BeleGted rate of revolution until the ~645 drilling to~rque exceeds the limit of llO inch-pounds or until 646 S0 holes have been drilled uith a single drill ~it. Table I 648 shows the results of testing several sulfurized compounds prepared according to t~his invention as ~ell as one com~er- 650 ~o~t7~7s , cially available cutting oil additiYe. In addi~cion, com~ina- 652 tions of the esters sulfurized with sulfur and with sulfur 654 monochloride and sulfur dichloride ~ere tested. 655 ' .

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~067479 .
From the aboYe data it can be seen that the 657 sulfuri~ed esters o~ this in~ention impart to lubricating oils 658 excellent properties for metal cutting operations. In 660 partic`ular, the sulfurized 2-ethylhexyl acrylates exhibited 661 properties far superior to the commercially available cutting 662 oil additive in the Drilling Torgue Test, and the combinations 664 of esters sulfurized ~ith sulfur alone~ and ~ith tbe sulfur 665 chlorides are superior to each employed by itself.~ This ` 667 Drilling Torque Test has been found fro~ experience ~o 668 :
correlate well with actual fLeld operations. 669 Exam~le 6 ~ 672 - .
SeYeral of-the above sulfurized carboxylates ~ere 674 tested to determine their~effectiveness as motor oil additi~es. 676 coPper-stri~-~orrosion Test , ~ 680 The Copper Strip Corrosion Test determ,ines cor- 682 ~'rosivity~of lobricating oils towards nonferrous -etals.~;In ~ 685 ~tbis test a copper strip~is~i~mersed~into~a lubricating~oil ~686 ~composltion containing,the,test additi-e.~ The lqbricati~g oil ~688 composition~is~maintainea~,at 250F (121C~ for 3 hours. The 690 degree~of discoloration of the copper strip i~s~obtained from a 691 comparison chart. ' A rating~of la in~dicates a very lo~ degree 692 of discoloration,a~nd consequently very slight corrosivity of , 694 the lubricating oil~co~positlon towards copper. Ratings of 695 bigher nu~bers such~as lb or 2a show higher reacti~ity, ~hich 696 ~: - , may~be;desirable for oils used under~he~avy loads. Purther ~697 details of this test ~ay be determinea ~y~reading ASTM Test ~ 698 : ~ Nethod D-130. ~he results of testing the compositions of this 699 ~ invention i~ the Copper strip Corrosion Test are set fortb in 700 .
Table II.~ ~ 701 QxidatoE Test The stability of an oil composition against oxidative 707 cba~ge is measured by the time required for the consumptio~ of 709 .

- ~0~'~47~ 1 one ~l) liter of oxygen by l00 grams of a test oil at 340P 710 (171nC). For convenience, the actual test uses 25 grams of oil 711 and the results are corrected to a l00-gram ~;ample~ A catalyst 713 containing a mixture of soluble salts is added to the oil ~hich 714 provides 95 parts per million (ppm) copper, eo ppm iron, 4.8 715 pp~m manganese, ll00 ppm lead and 49 ppm tin. Table II reports 717 ~alues obtained from subjecting the lubricating oil compo- 118 sitions o~this invention to the Oxidator ~ q'est. 720 Four_Ball Wear Te_t 723 A~nti~ear proper*ies: of l~bricating oil additiYes ~ 729 under boundary lubrication conditio~s can be determined by 726 means of the uell-kno~n Four-Ball Test. In this test three 729 l/2~'-dlameter steel balls are clamped together and immersed in 730 the test lubricant. A fourth steel ball is rotated at about 731 1800 rpm in contact with three other~balls. A speciied load, 733 in this case 20 kilograms, is applied, forcing the rotating 734 ball against the three stationary balls. The test is~ run for 735 60 minutes and the sizes of the ~ear scars on the three 736 stationary balls are measured and the a-erage scar size in 737 mlllimeters is reported. The smaller the scar, the greater the~ 738 antiwear properties of the test lubricant. Por example, base 740 oils common1~ gi~e ~ear scars of 0.60 m-~or greater at 20-kg ~41 load. Generally lubricants which give a ~ear scar of less than 742 0. 5 mm at 20-kg load are considered acceptable antivear agents 743 and lubricants ~hich giYe ~ear scars~of less than 0.4 ~m at 20- 745 kg load are considerPd exceptionally qood antivear lubricants. 746 Table II sets ~forth the results of testing lubricating oil 747 compositions according to this invention in the Four Ball ~ear 748 Test.
Palex Extreme Pressure Test 752 .___ ___________ ~he capability of lubricating oil compositions to 754 lubricate under extreme pressures can be measured by this test~ 757 1067~79 The Falex ~achine is ~anufactured by the Faville-LeVally 75 Corporation o~ Chicago, Illinois. In this te~st t~o opposing 760 stationary V-blocks are pressed by a nutcracker arrangemPnt of 761 lever arms to~ardæ each other against an interposing rotating 762 steel shaft. The rotating shaft lS driven by a chuck through a 763 brass shear pin. The V-block and pin test specimens are 764 immersed in a ~essel of the test lubricant at a preselected 765 temperature. The machine is~operatea 290 rpm and the specimens 766 are broken in at 300 po~nds loading. During the test, loading 768 bet~een the V-blocks and t~e rotatiDg pin is increased 769 auto~atically until seizure occurs. This failure point is 77q indicated by sheering of the brass pin holding the rotating 773 shaft. The load at ~ailure in pounds is taken as a quanti- 774 tative easure of the extre~e-pressure properties of tbe oll ~776 compositions. ni~eral oils may fail at 600 to 900 pounds. 778 Oils vith moderate extreme-pressure additives ~ill fail at lOOO 780 to 2000 pounds~aDd~very effecti~e extre~e-pressure additives ~ 782 .
will permit loadings in excess of 3000 pounds.~ The limit of 783 the test machine i5 4500 pounds. The results of testing oil 785 composltions of this i~ention in this ~test are~ set forth in 7a6 Table II. ~ ~ ~ 787 Lubricating oil composi~ions according to this inven- 788 tion ~ere prepared fro~ sulfurized butyl acrylate contam ing 789 20g~ sul~ur and sulfuri~ed 2-ethylhexyl acrylate containing 790 19%~ sulfur. These sulfurized~additives were ad~ded to a base~ 792 oi} vhich was a neutral, solvent-refined lubri~cat~ing oil having 793 a viscosity of 480 S~S at 100F. This base oil contained 6%w 7g5 - .
of a polyisobutenyl succinimide produced by reacting succinic 797 .

anhydride substit~ted ~ith a polybutenyl group having a number 799 a~erage ~olecular ~eight of about 950 ~ith ~etraethylene penta- 801 mine at an a~ine ~o s~cci~ic a~hydride ~ol ratio of about 0.87. 802 The base oil also contained 0.1%w of terephthalic acid. The 804 e~r~ - 20 - ~

- ~06'~479 results of testing this base blend in the abo~e-described tests 805 are also set forth in Table II. ~ 806 :

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~olf;7479 As can be seen from the abol~e data, the lubricating 808 oil compositions of this invention provide excellent anti- 809 oxidation properties, antiwear protection and extreme-pressure 810 protection. Ho~ever, copper corrosivity is relatively high but 812 no higher than that found in some sulfur-containing lubricating 813 oil used successfully as motor oils. ~ 814 Ex~mPle 7 --_a~lrin~_Wei~t Loss_Test 817 a lubricating oil composition of this invention ~as 819 tested ~in t~e L-38 Bearing~ Welght ~Loss Engine Test. In this 822 test the lubricating oil used contained 6~ of the same :823 polyisobutenyl succinimide described abo~re in Example 5, 0.1%w 824 terephthalic acid~ 0.8%w tetrapropenyl succinic acid,~ 1%~ of 825 sulfurized diparaffin polysu1fide ~17.5%~ sulfur), 1.5~ of 827 sulfurized 2-ethylhexyl acrylate containing approximately l9Xw ~28 sulfur and 0.l~6~ benzotriazole as a copper deactivator. In 830 ~thls test the test oll had a~ copper~corrosivity rating of 3a, a 831 ~; significant improve-eDt o~rer the 4c rating sho-dn in Ta~le II, ~832 a~d a bearing ~eight ~loss after 40 hours of 33 mg. In this 833 tes~ a bearing ~eight loss of less than 40 mg after 40 hours of 834 - :
operation is acceptable. ~ 835 ~ . :
: ~ E~am~_8 ~ : ~ . 838 The tests of Example 6 ~irere repeated on lubricating 840 oil compositions of this invention. In this series of tests 843 the base oil contained no additional additives. The base oil 845 .
~,ras a solvent-refined neutral lubricating oil ha-Jing a 846 viscosity of 480 S~S at 100P. The results of the test are set 84~
forth in Table III............................... : 848 , .

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10~7~7~ , As can be seen from the above data, the lubricat~llg 850 oil compositions of this invention possess excellent ~51 antioxidant, anti~ear and extreme-pressure lubricating 852 prope rtie s.
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A lubricating, cutting or metal working oil composition comprising (a) a major amount of an oil of lubricating viscosity, and (b) an amount effective to impart extreme-pressure and/or antiwear lubricating properties to said oil of a sulfurized ester of an olefinic mono- or dicarboxylic acid, said ester being free of allylic hydrogen atoms and of phosphorus.

2. A composition as in claim 1 wherein said acid has a carbon atom content in the range of from 3 to 200 and the alcohol of said ester has a carbon atom content in the range of from 1 to 30 carbon atoms.

3. A composition as in claim 2 wherein said sulfurized ester contains an amount of sulfur in the range of from 0.5 to 2 mols per ole-finic bond of said acid.

4. A composition as in claim 3 wherein said ester contains, by weight, an amount of sulfur in the range of from 0.1 to 10 percent.

5. A composition as in claim 1 in which prior to sulfurization said ester of an olefinic monocarboxylic acid has the formula or said ester of an olefinic dicarboxylic acid has the formula wherein (1) x represents 1, 2 or 3; (2) each Rindependently represents the remainder of an esterified alcohol having a carbon atom content in the range of from 1 to 30: and (3) each Z independently represents hydrogen or a hydrocarbyl group free of allylic hydrogen atoms.

6. A composition as in claim 5 wherein each R independently represents the remainder of an esterified alcohol having a carbon atom content in the range of from 1 to 12 and each Z independently represents hydrogen or a hydrocarbyl group having a carbon atom content in the range of from 4 to 30.

7. A composition as in claim 6 wherein said R has a carbon atom content in the range of from 4 to 8 and said Z represents hydrogen.

8. A composition as in claim 7 wherein said ester contains, by weight, an amount of sulfur in the range of from 0.2 to 5 percent.

9. A composition as in claim 1 wherein said sulfurized ester is the reaction product of sulfur, sulfur monochloride or sulfur dichloride with an ester of an olefinic mono- or dicarboxylic acid, said ester being free of allylic hydrogen atoms and of phosphorus.

10. A composition as in claim 9 wherein said acid has a carbon atom content in the range of from 3 to 200 and the remainder of the alcohol of said ester has a carbon atom content in the range of from 1 to 30

11. A composition as in claim 9 wherein said sulfurized ester product contains from 0.5 to 2 mols of sulfur per olefinic bond of said acid.

12. A composition as in claim 11 wherein said ester of an olefinic monocarboxylic acid has the formula or said ester of an olefinic dicarboxylic acid has the formula wherein (1) x represents 1 or 2; (2) each R independently represents the remainder of an esterified alcohol having a carbon atom content in the range of from 1 to 30, and (3) each Z independently represents hydrogen or a hydrocarbyl group free of allylic hydrogen atoms.

13. A composition as in claim 12 wherein said carbon atom content range for R is 1 to 12 and said hydrocarbyl group for Z has a carbon atom content in the range of from 4 to 30.

14. A composition as in claim 13 wherein said carbon atom content range for R is 4 to 8 and said Z is hydrogen.

15. A composition as in claim 9 wherein said reactants are said ester and sulfur dichloride.