US2436272A - Mineral oil composition - Google Patents

Description

Patented Feb. 11, i948 2.43am mm on. COMPOSITION George IL- S. Snyder, Woodbury, Ralph V. White, Pitman, John 1!. Bishop, Wenonah, and John Socoloisky, Woodbnry, N. 1., assignors to Snoo y-Vacuum Oil Company,

corporation of New York Application February 27, 1945, Serial No. 580,074

. No Drawing.

1 Claims. This invention has to do with lubricants and. more particularly, has to do with lubricants for ferrous metal surfaces in an environment where such surfaces are-also subject to contact with water and in consequence are likely to rust.

As is well known to those familiar with the art. difnculties have been experienced during the operation of steam turbines and particularly during the initial operation of new steam turbines because of therusting of the ferrous metal parts. The combination of fresh (not previously used) oil, clean new metal surfaces, and moist OOIldl-r tions of operation of new steam turbines appears to be particularly conducive to rusting difllculties. Particles of rust depositedon or carried to bearing surfaces of small clearance such as the governor, for example, tend to cause sticking which renders them inoperative. In cases of severerusting bearings may be. injured.

The aforesaid rusting phenomenon is evidently the result of improper or. inadequateflwetting" of we metal'surfaces with oil thus permitting apreferential contact of the" surfaces with the water which is present. 'Numerous materials have been proposed for use in suchoils to counteract the inadequate "wetting" effect: unfortunately, however, such materials have generally Incorporated, a

from six to eight carbon atoms substituted for the carboxylic hydrogen atoms of malic acid and being present in the mixture in a molar quantity of from about 40% to about 80%, and another of 'said esters having two long-chain aliphatic lar proportions ofa short-chain aliphatic group and of a long-chain aliphatic group of the type given rise to otherrundesirable phenomena. For

example,'many organic esters which have been suggested for use in turbine oils and-the like to correct the rusting action normally characteris tic thereof,have proven to be undesirable inasmuch as they formemulsions' withlthe oiland are used. As'iis well known. 'emulsionss'eriously reduce or impair the high 1 degree of lubricating water present in theenvironment in which they efficiency required-in turbine operation andare to be religiously avoided. Typical of the organic esters which inhibit ther'ustin'g action of turbine oilsand the like but whichgive rise to emulsions are those obtained by reaction of alcohols and oxy-polycarboxylic acids; representative of such esters is dioleyl malate.

The present invention is directed to an outstanding mineral oil. which is substantially free from the aforesaid rusting'and emulsion diflicul defined above; and those oils which contain a:

mixture ofmalic estersin'which one of the said esters has two short-chain aliphatic groups and another of said esters has two. long-chain aliphatic groups of the type defined above, the

esters being presentin the mixture in .equimolecular proportions. It will be apparent, therefore, that chemical and physicaimixtures of such esters, characterized as described above. are co tem lated by the presentinvention.

The short-chain aliphatic groups which contain from six to eight carbon atoms may be wholly saturated or partially saturated and may be either straightor branched-chain or cyclic in structure, although a wholly saturated branchedchain group such as 2-ethyl hexylisjpreferred. Specific examples of such groupsyaren-hexyl, cyclohexyl, n-heptyl, n-'-octyl and the preferred 2-ethyl hexyl group. Correspondin y, long-' chain aliphatic groups which contain at least twelve carbon atoms, and preferably from twelve to eighteen carbon atoms," may bewholly saturated or partially saturated and may be either straightor branched-chain in structure and, of

such groups the normal, partially saturated group oleyl is preferred. Illustrative of such.

groups are lauryl, '7-ethyl-2-methyl undecyl, cetyl, oleyl and stearyl. It will be apparent to those familiar with the art that the foregoing aliphatic groupsmay be introduced into the malic esters contemplated herein by reacting the corresponding alcohols with malic acid. It is to be understood, however, thatsuch groups may be ties. The outstanding mineral oil of this invention comprisesja yisc'ous mineral oil having in.

admixture therewith a small amount'of an ester of malic acid obtained'by reacting one molar equivalent of malic acid with fromabout 0.8 to about 1.6 molar equivalents of. a short-chain alcohol havingfrom six to eightcarbon atoms and with from about 1.2 to about 0.4 molar equivalent of a long-chain alcohol "having atleast introduced by all other proceduresknown in the errand tnat'the invention is not to'be limited in zany sense by the method of preparation of the twnlve'carbon atoms. The. present invention is also predicated upon the discovery of an oil similarly characterized comprising a viscous mineral oil containing a small amount of a mixture of esters of malic acid, one of said esters having two short-chain aliphatic groups containing said esters. l

The following-example is presented in order to clearly'demonstrate a malic ester of the type contemplated herein.

Example 'Malic acid .(20.1 grams: 0.15 mole), occncl (40.2 grams;- 0.15 mole) predominantly oleyl alcohol and having a hydroxyl number, of 210, and 2-ethyl hexanol (23.5 grams;-- 0.18 mole) were. digested for 3% hours at -120 C. in afiask provided with-a reflux take-on. Inasmuch as some 2-ethyl hexanol distilled out of the reaction mixture into the reflux take-off during digestion, a 0.03 mole excess of 2-ethyl hexanol was used in order to maintain a reaction mixture having substantially equal amounts of the said alcohols. Thereafter. toluene was added to the reaction mixture and the resultant mixture was then reiluxed at Mil-145 C. for about 7 hours. During the latter period about 4.9 cc. of water was collected in the reflux take-off, evidencing the formation of the esterof malic acid. The reaction mixture was filtered. Toluene was removed from the filtrate obtained thereby. by heating under vacuum to a maximum liquid temperature oi 100 C. at 3 mm. pressure. The ester product oi malic acid thus obtained had a neutralization number (n. 11.) of 20 and is believed to be predominantly one'isomeric form or a mixture of both isomeri forms of 2-ethyl hexyl, oleyl malate. It is probable, however. that small amounts of dioleyl malate and dim-ethyl hexyl) malate are present in the product.- a I The number 01' carbon atoms in the aforesaid aliphatic groups and the proportions of the said groups in the malic acid esters of this invention are critical and, it not maintained, esters appreciably inferior to those desiredand contemplated are obtained. Esters oi. malic acid obtained by departing from the aforesald critical limitations have been found to either fail as rust inhibitors, such as dio tyl malate mentioned above, or cause substantial and deleterlpus -emulsions to form in an environment containing oil and water. This relationsh p is demonstrated hereinafter by rust and emulsion test results. a

To demonstrate the outstanding character of the oil compositions contemplated herein, typical rust and emulsiontests were carried out with a mineral oil, withblendsoi the mineral oild small amounts of malic esters of the typede" Ted hereinabove, and with blends of the mineral oil and small amounts of related, inferior malic esters. not contemplated herein. The malic esters so tested are identified by their acidity as measured by their neutralization numbers and by their composition interms of molar equivalents oi. short-chain aliphatic groups and of long-chain aliphatic groups. l h e esters described in the table below as malate mixtures are prepared in the manner shown in the-example above wherein definite molar quantities of a long-chain alcohol and of a short-chain alcohol are used to esterii'y malic acid; and the esters, described in the table as physical mixtures" are obtained by blending acid with definite proportions of a short-chain ester of thesame acid. The oil used is a blend oi solvent-refined, Mid-Continent residual stock with a 'fsolvent-reflned, Mid-Continent Rodessa distillate stock and has an A. P; I. gravity of 30.8, a flash point of 445 F. and an S. U. V. of 407.! seconds at 100 F.; and had in admixture therewith, 0.2% o! 2,6-ditertiary butyl--methyl phenol, a well known antioxidant. The oil is suitablefor use in turbines and the like, and the tests run on the oil and oil blends simulate conditions existing in turbine operation and analogous operations.

The rust test used involves soaking a small disc of polishedsteel having a slightly concave surfacein the oil under test at 90 F. for minutes, and thereafter placing a drop 01 distilled water below 'the surface of the oil 'and upon the surface of 'the steel disc. The test is then continued for 24 hours at 90F. At the end of the-latter periodthe steel disrshould nothave' rust formed thereon in order that the oil pass" the test; it rust has formed on the-disc during' this period, the'oil'under observation fails the" test.

The emulsion test -used herein is the emulsion test for lubricatingoils (Method 320.13) described in the Federal Stock Catalog.'sectio1 1 IV. part 5, Federal Specifications VV-L-IQlb, February, 19; 1942. In this test, 401:0.101'011' under observation and 40 cc. of emulsant;-either distilled water or a 1% salt (NaCl) solutionaare stirred with a paddle at 1500 R. P. M. for Sminutes in a cc. cylinder at the prescribed-temperature of F. Separation of the emulsion formed therein is observed while the cylinder is kept at the prescribed temperature for a specified time interval. Figures given in the chart provided in the catalog identi-'- fled above are the actual minutes at which there is no continuous layeroi the emulsion remaining betweenthe oil and water; With an oil having a viscosity similar to: that of the oil used in this test, specifications require that no continuous layer of emulsion remain at the interface after a 30 minute period. Results of the aforesaid rust and emulsiontests are set 101111111 the table below. For' convenience an asterisk I) has been'used throughout the table tov indicate' those oil blends which have failed to pass one or both of the said tests and has alsobeen used to designate those oil blends not contemplated by the present 'inven-' tion. I

A. Chemical Mixtures ,Emnlsion'lest oi2-cthylhuyholeyl l 1' filled 17 N 01 I 9 n a gg, @255 mm Teat Wa'te'rf Solution gglg' Molesof m.- 101- (Minutes 101- complete c310! separation) Fail'....... 2 1 1 a0 0 20.0 0.0 .do 14 10 1.0 .4 220 0.2 23 .11. 1.4 0.0 220 .02. as. 15.. 1.2 0.8 21.0 0.2 20 17' 1.0 1.0 200 I 0.2- -22' 1a- 0.0 1.1 1&0 a2 10 2 0.8 1.2 20.0 0.2 20 2s- 01 1.3 11.0 0.2 22' 27; a0 1.1 10.0 0.2 3a 30. -0.0 1.5 1110 02 =32 20 0.4 1.0 1&0 0.2 --a9 -za- '0 '20 14.0 0.2 '42. -40

a. Pa l Mixtures Emulslon 'leut N Com I Distilled 1%Na0l :Dbhmyl mole Ester percent Rust Test Water Solution hetlyl mizimfalo,

a mo 9 mo pet (Minutes for com plate percent cent separation) Fall-"ml 1 100 0 .25.0 0.2v .d0.' 14 70 30 22.4 0.2 Pass. 24 Z! 40 60 20.6 0.2 .do.... 27 30 G. (ilnmlcal mlxtilres Emulsion Test,

of 2-et11yl hexyl, octadecylmalate Di m d 0 at e 17 Na .1 l as z r 223;} Rust test water s lution Mole! 01 Males of p 2iethyil made: 1 (M1 my nutes lor c'ompleto alcohol 1 I .seporatlon);

- l 2 "1. 2.0 '0 25.0 0.2 14 10 I '1.8 0.2 24.0 0.2 21 1.0 0.4 22:0 0.2 l 30 14 1.4 0..6 21.0 2 28 17' 1.3. 0.7K I 22.0 0.2; 23 27 1.0 1.0. 21.0 0.2' 23 .18 0.0 1.1 16.0 0.2 30 8' 0. 8 1. 2 23. 0 0. 2 23 2Q 0.6 1.4 20.0 0. 2

"n be. ofolnulalon after 1 hr. "'15 cc. of emulsion after 1 hr. ""134 00. 01 emulsion after 1 hr.'..

w gl l w Emulsion Test mwhyl mocm fi' Con ci. mm Distilled 1% NaCl he! .decyl Ester per cent Test Water 1 Solution malalte, malalte, I

mo 9 mo 0 I (Minutes for comper cent. per cent plate s eparatlon) 70 an 22.4 o. 2 '22 25 60 40 21. 7 0. 2 20 Z; b0 21. 2 0. 2 28 30 30 1 20. 3 0. 2 27 30 '20 19. 8 0. 2 '58 21 '10 '90 19.4 0. 2 36 "1 cc. of emulsion after 1 hr. 134 on. o! amulaion after 1 hr.

B. Chemical Mixtures ofone mole of Emulsion ms mallcacld nnd- Dis- 7 b? Conc., Rust tilled ggi f Ester percent Test Water Mole; of Short- Molea of bonfi-chaln Chain Alcohol Alooho (Mlnutealor'oom- V I plate aeparatlon) Falla. 1 i

1.0 n-he l 1 0 0 22. 0 0. 2 Pass 17 17 1.0 cycloexyL. .c 52.0 0.2 .do.. 18 30 1.0 n-ilepty 13.0 0. 2 .d0.. 13 14' 1.0 lnurgl. d 26.0 0.1 .do '48 '45 1.0 2-el: y Lododecy 22.0 0.2 .do.. 24 11 Do... 1.0 7-ethyl-2methyl 47.0 0.2 "do... 15 14 undecanol. Do... 1.0 hexa-decyl 20.0 0.2 .do... 20 22 The data in section A o! the table above for the oil and for the oil blends containing 0.2% the various chemical mixtures of 2-ethyl hexyl, oleyl malate eflectiveiy demonstrates the superiority oi the oil compositions contemplated herein. As shown in section A, the oil alone fails to pass the rust test, although the emulsion characterlstics thereof are satisfactory. An oil blend containing di(2-ethyl hexyl) malate also fails to pass the rust test, yet has desirable emulsion characteristics. when the ester product blended in the oil is obtained by reacting one molar equivalent of malic acid with irom about 0.7 to about 1.6 molar equivalents of z-ethyl hexyl alecho] and with from about 1.3 to about 0.4 molar equivalent of oleyl alcohol, the oil blends have desirable rust and emulsion characteristics inasmuch as they readily pass both tests. Yet, when the ester product is obtained by reacting one molar equivalent of malic acid with less than about 0.6 molar equivalent of 2-ethyl hexylalcohol and with more than about 1.4 molar equivalents of oleyl alcohol, oil blends containing the same fail to pass the emulsion test, although they pass the rust test.

Oil blends containing physical mixtures of the malic acids obtained by blending dioleyl malate and di(2-ethyl hexyl) malate are shownv in section 13 of the table. The results provided therein indicate that eflec'tive blends are obtained with 40 through 70 mole per cent of di(2-ethyl hexyl) malate and with 70 through 30 mole per cent of dloleyl malate.

The results shown in section C of the table are similar to those shown in section A. in that the results for chemical mixtures of z-ethyl hexyl, octadecyl malate have the same critical proportions, namely, trom about 0.8 to about 1.6

molar equivalents of the short-chain alcohol, such as 2-ethyl hexyl, and from about 1.2. to

about 0.4 molar equivalent of the long-chain al- Section D of the table carries results of the said tests with oil blends f containing small amounts otphysical mixtures;

cohol, such as octadecyl.

of dl'wtadecyl malate and M dim-ethyl fi i about; 0.4 molar equivalent of a long-chain alimalate. These results also indicate the eflective phatic alcohol having between twelve and about ness of the ester mixtur mum within the aforesaid critical limit or on compositions oontainiii g auo'aoid esters of the type contemplated herein along with an ester mixture not contemplated-lauryl, oleyl malate-are shown in section E-oi the table. These results demonstrate the critical nature of the mixture of the aliphatic groups: that is, that one such group shouldcontain from six to eight carbon atoms and another should containat least twelve carbon atoms. For example, lauryl, oleyl malate contains one aliphatic group having twelve carbon atoms and another having eighteen carbon atoms and when blended in the oil does not pass the emulsion test.

The malic acid esters of this invention may be used in oils in amounts oi from about 0.1% to about 1.0% although preferred concentrations are of the order of 0.2% and 0.3%. They may also be used in larger concentrations, of the order of 1% and greater, in cutting oilsand the like.

These esters may also be used alone in oils and may also be used in oils containing one or more additives. For example, they may be used in oils, with oxidation inhibitors, film strength improving agents, oillness agents, etc. Typical of such additives are the well known phenols, amines, sulfides, organic compounds containins phosphorus, organic compounds containing haiogen, etc.

It is to be understood that although the invention has been illustrated hereinabove by certain preferred esters and oil blends of the same, it 'is not to be restricted thereto but is to be broadly construed in the light of the scope of the appended claims.

We claim:

1. A mineral oil composition comprising a viscous mineral oil having in admixture therewith a minor proportion, sufiicient to impart antirusting characteristics to said oil, of an ester product of malic acid selected from the group consistingpf: an ester product of malic acid obtained by reacting one molar equivalent oi malic acid with from about 0.8 to about 1.6 molar equivalents of a short-chain aliphatic alcohol having from six to eight carbon atoms and with from about 1.2 to about 0.4 molar equivalent of a long-chain aliphatic alcohol having between twelve and about eighteen carbon atoms; and a mixture of esters ofmalic acid. one of said esters having two short-chain aliphatic groups containing from six to eight carbon atoms substituted for the carboxylic hydrogen atoms of malic acid and said ester being present in the mixture in a molar quantity of from about forty to about eighty per cent, and another or said esters hav-. ing two long-chain aliphatic groups containing between twelve and about eighteen carbon atoms substituted for the carboxylic hydrogen atoms of malic acid and said ester being present in the mixture in a molar quantity of from about sixty to about twenty per cent.

2. A mineral oil composition comprising a viscousminerai oil having in admixture therewith a ing one molar equivalent of mallc acid with from a about 0.8 to about 1.6 molar equivalents of a short-chain aliphatic alcohol having from six to e ht carbon atoms and with from about 1.2 to

' eighteen'carbon atoms; and a mixture of esters 10 hydrogen atoms of malic acid and said ester being present in the mixture in a molar quantity of from about forty to about eighty percent, and another of said esters having two long-chain aliphatic groups containing between twelve and about eighteen carbon atoms substituted for the carboxylic hydrogen atoms of malic acid and said ester being present in the mixture in a molar quantity of from about sixty to about twenty per cent.

3. A mineral oil composition comprising a viscous mineral oil normally permitting rusting oi ferrous metal surfaces in the presence of water, having in admixture therewith a minor proportion, suillcient to retard said rusting, of an ester product of malic acid obtained by reacting one molar equivalent of malic acid with from about 0.8 to about 1.6 molar equivalents of a shortchain aliphatic alcohol having from six to eight carbon atoms and with from about 1.2 to about 0.4 molar equivalent of a long-chain aliphatic alcohol having from twelve to eighteen carbon atoms.

4. A mineral oil composition comprising a via tion, suflicient to retard said rusting, oi an ester .product of malic acid obtained by reacting one molar equivalent of mallc acid with one molar one molar equivalent oi a long chain aliphatic alcohol having from twelve to eighteen carbon atoms. 7 I I v 5. A mineral oil composition comprising a viscous mincraloil normally permitting rusting oi ferrous metal surfaces in the presence ofwater. having in admixture. th erewith, a minor proporr hydrogen atoms oi malic acid and said ester betion, sufllcienttor'etard ssis"orsnester= .""ing' present "in the mixture in'a 'molarquantity 4 p d ct. at a a ob a ne byresa ils on molar-equivalent oi. inallc' acidwith from about;

0.8 to about 1.6.molar equivalents of 2-ethyl hexyl' alcohol and withironi nbout lj to about 0.4 molar equivalent or oleylalcohol.

s. Amman ollf'co pbsition coinprlsing cous mineral oil normally permitting rusting'oi ferrous metal surfaces in the "presencool' Water. having in admixture therewith a minor proportion, sufilcientto retard said jrustin'mbian ester product] of malic acidobtainedby reacting one molar Iequivalentoi malic with from about 0.8 to about 1.6 molar equivalents oi Q-ethyl 0.4 molar equivalent or octadecyl alcohol.

having in admlxture'therewith 'a minor proportion, sufficient to retard said rusting, of an ester product of'malic acid, obtained by reacting one molar equivalent oi' mallc acid with from about 0.8 to about 1.'o 'molar-;equivalent o! fl-ethyi hexyl alcohol and with from about 1.2 to about 0.4 molar equivalentoi hexadecyl alcohol.

8.- A mineral oil composition comprising a viscous mineral oil'riorinally permitting rusting of ferrous metalsuriacesj in the presence of water. having iii-admixture therewith a minor propor'- tion, sufiicient to retard said rusting, 0! a mix! ture of esters or malic'acid,uone of said esters having two short-chain aliphatic groups containing rromsixto-eightcarbon atoms substituted for the carboxylio hydrogen atoms oi malic acid and said esterbeing present in the mixture in a molar quantity or from about 'iortyto about eighty-2 per cent, and another of said esters having two long-chain aliphatic groups containing iromtwelve to eighteen carbon atoms substituted for the carboxylic hydrogen atoms of malic acid and said ester beingpresent intheinixture in a molar quantity or irom about sixty to about v twentynerce t,

ad'r'i'iixtfirtlierewith sis-minor.v propel-e.

.. minor'proportiom at least about 0;

more O I. mineral oil composition comprising 5Y1! taining from-six to eight carbon atoms substituted for the carboxylle hydrogen atoms of malic 1. acid and said ester being present in the mixture in a molar quantity of about fifty per cent, and

another of said esters having two long-chain aliphatic groups containing from twelve to eightof about iiity'per cent. o

10. A mineral oil composition comprising aviscous mineral oil having in admixture therewith a of an ester product of malic acids the group consisting'oi: an ester product-o! malic acid obtained by reacting one molar equivalent of. 'mallcacid with iromaboutuafto about 1.8 molar a equivalents of a short-chain aliphatic alcohol having from six to eight carbon atoms angi wlm.v i from about 1.2 to about 0.4 molar equivalent'ot a long-chain aliphatic alcohol having. between twelve and about eighteen carbon atoms; and a. a ,mixtureoi esters oi-malic acid, one or saidesters having two short-chain aliphatic groups contain :1. in! 1mm slx to'eight'carbonatoms substituted 7 tor the carboxylic' hydrogenatoms oi malic'acld 1 and said ester being present in the mixture in a as molar quantity of'irom about forty to about eighty per cent, and another of said "esters having two long-chain aliphatic groups containing between twelve .and about; eighteen carbon atoms substituted for the carboxylic hydrogen 40 atoms of malic acid and said ester being present i. in the mixture in a molar quantity of i'r'om about sixty to about twenty per cent. a GEORGE E. S. SNYDER.

RALPH V. WHITE.

r JOHN H. manor.

v Joann soconor'smr. REFERENCES err-an 'tmrrnn sums m'mm's Number Name Date.

1,993,186 Graves Mar. 12, 1935 2.101.221 wet-nu Dec. 1, mar 2,210,200 l 'arrington Feb.27,1946 ,zsvosoo Farrington Feb.2'l.1945 Blair, Jr. May a, 1m

neral "oil norma lyv Permittingjrustingf or ferrous .metal surfaces inithe presenceoi water.

can carbon atoms substituted for the carboxylio' Certificate of Correction Patent No. 2,436,272. Februery 17,1948.

GEORGE H. S. SNYDER ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 7, line 64, for 0.1% read 0.01%; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of May, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner 0 Patents.

Certificate of Correction Patent No. 2,436,272. February 17,1948;

GEORGE H. S. SNYDER ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 7, line 64, for 0.1% read 0.01%; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 4th day of May, A. D. 1948. 7

THOMAS F. MURPHY,

Assistant Gommz'sst'oner of Patents.