US2396487A - Chloraralkyl esters of thio acids - Google Patents

Description

' l atented Mar. 12,1946 I I I 't'ions.

. posed only of a petroleum fraction is incapable E. P. agents may be derived include carbothiolic subjected to unusually heavyloads per unit area carbodithloic a s -C H r. d n

. is composed of a suitable carryingagent, such as UNITED STATES PATENT. OFFICE CHLORARALKYL ns'raas 0F r1110 ACIDS Edward s. Blake, Nitro, W. Va, assignor to' Monsanto Chemical Company, .St; Louis, Mm, a corporation of Delaware No Drawing. Original application June 17, 1944,

Serial No. 540,891. Divided and this applica- I tion June 28, 1944, Serial No. 542,607

Claims. ((31.260-455) This invention relates to lubricating composiagents. The addition to hydrocarbon or fatty tions and to methods of preparing the same and lubricating oils of small amounts of chloraralkyl more particularly to lubricating compositions cstersof thio acids provides lubricating compoadapted for use under extreme pressure condisitions which not only satisfy all of the primary requirements of extreme pressure lubricants but,

Various types of modern machinery such as 'in addition donot tend to form sum. 19111 Or the hypoid gears in motor vehicles'develop enorcorrode metal surfaces nor separate into their mous' pressures between engaged surfaces. The onstit nt par in 10118 n inu 11 a ordinary type -of hydrocarbon lubricant comples of suitable thio acids from which the new of satisfying the severe requirements demanded acids (R-GOSH), carbothionic acids in the proper lubrication of hypoid. gears, bear- (MS 9H) ing surfaces, metal cutting toolsand the like,

of surface. This fact has led to the development 15 t t lo'carbenlc acids of the so-called extreme pressure lubricant which v Y (Mix mineral oil, and another ingredient which imparts tothe lubricating composition the property Where Y is xyen at least one Y being of maintaining between the engaged surfaces a 205 n tmocalblnic acids countered.

. Among the various E. P. bases which have been lubricating film under the high pressures en-. a

' u-cssn) prepared and which have met with varying degrees of success are organic materials which con- 2 In Keneml derivatives 0 thiocfll'bomc acids tain sulfur or both sulfur and chlorine. The pres- P rr ha is to Say products of the structure a ent invention relates to the general type of or- I Y I ganic materials which containboth sulfur and 11 chlorine. The presence of chlorine frequently increases the effectiveness of organic sulfur comwhere R is a chloraralkyl radicle, Y is sulfur or Pounds but this increased effectiveness is accomoxygen atleast one of them being sulfur and panied by increased corrosiveness and decreased R represents alkyl, aryl, aralkyl or alkyaryl.

stability. However, the new adjuvants while con- The amounts of chloraralkyl esters required to siderably more effective than the corresponding be added to hydrocarbon or fatty lubricating oils chlorine free sulfur compounds actually appear for the preparation of compositions of this invento be more stable and are not corrosive. tion vary somewhat, depending .upon the char- A primary object of this invention is to proactor of the lubricating stock used as a base, and I vide a new and novel sulfur-and-chlorine-conthe severity of the rvic for which they are I taining material capable of imparting extreme designed; however, the active agent is always pressure lubricant properties to a lubricating oil present in minor amounts with respect to the oil composition otherwise incapable of withstanding base and in general varies between about 1% and extreme pressure conditions. A further object about 10% of the oil base by weightalthough is to provide a mineral oil adjuvant which is not amounts outside of this range canbe used where corrosive and yet is a very effective extreme presconvenient or desirable. Since most of the presure addition agent. Still further objects are to ferred adiuvants are freely soluble in lubricating provide extreme pressure addition agents which oils, 9. wide range of homogeneous compositions are cheap and easily prepared, can be prepared. Where desired concentrates can In accordance with thisinvention it has been be prepared containing relatively large amounts, discovered that chloraralkyl esters of thio acids as for example of chloraralkyl esters of a are very effective extreme pressure lubricant 5 thio acid. Such concentrates may be stored or transported in this form and diluted to the desired concentration before actual use. Complete.

solution is not always necessary and incorporation the less soluble active agents in-suspended form is suillcient to allow them to function in decreasing film strength in actual use.

There are a variety of procedures suitable for the preparation or the new adjuvants and in general any of the methods suitable for the preparation of esters of thio acids can be used. A particularly convenient synthesis which has been found to give excellent yields is to react a chloraralkyl chloride with an alkali metal salt of the thio acids and separate the salt split out in the formation or the desired ester. examples describe in detail the synthesis of chloraralkyl esters typical of the new class of adjuvants but it is to be understood that the invention is not limited thereto.

PREPARATION OF TRlICHLOR BENZYL I Substantially 1500 parts by weight of dry toluene were charged into a chlorinator 0! suitable capacity. Substantially parts by weight 0! iron filings were added as catalyst carrier for ring chlorination and chlorine introduced atabout C. until the increase in weight corresponded to that calculated ior trichlor toluene. The temperature was increased to 70 C. during (the last part of the reaction and the flow of chlorine interrupted when the product analyzed 54.8 chlorine. The trichlor toluene was washed with 10% caustic and filtered through a bed of clay in order to remove the iron and chlorinated at 160 C. in the presence of ultra violet light until the gain in weight was that calculated tor trichlor benzyl chloride. Analysis of theproduct for chlorine at this point gave 61.8%.

Exmnl I Trichlor benzultrithiocarbonate Into a vessel of suitable capacity there was charged 316 parts by weight (substantially 1.32 molecular proportions) of Na:S.9HzO, 138 parts by weight (substantially 1.82 molecular proportions) of carbon disulfide and substantially 2500 parts by weight of methanol. The mass was stirred for about four and one-halihours and then 550 parts by weight (substantially 2.39

molecular proportions) oi! trichlor benzyl chloride added in a slow stream during which the temperature oi the reaction mixture was held at 2540 C.

After the addition was complete, the temperature was raised to refluxing temperature for about four hours and the solvent removed as for example, by distillation under a vacuum and the residue washed with water and dried. The prod- 'uct was a brownliquid which was readily soluble in mineral hydrocarbon oils.

EXAMPLE II Trichlor benzyl butyl trithiocarbonate A'mixture of 181.5 parts by weight (substantially 2.02 molecular proportions) of butyl mercaptan and substantially 1200 parts by weight of ethanol was added to 79 parts by weight or 96.5% caustic soda (substantially 1.90 molecular proportions). The mass was cooled to 15 C. and 200 parts by weight (substantially 2.63 molecular proportions) of carbon disulflde added thereto which caused thetemperature to rise to about 28 C. 400 parts by weight (substantially 1.74

The following asoe,4e7

molecular proportions) of trichlor benzyl chloride was added in a slow stream during which the temperature of the mass was kept at 30-40 C. The mixture was then heated to refluxing temperature for tour hours and-the solvent removed as. for example by distillation under a vacuum and the residue washed with water and dried. The product was a brown liquid very soluble in mineral hydrocarbon oils.

Exaxrn: III o-Chlor benzyl butyl trithiocarbonate Into a reaction vessel of suitable capacity there was charged 49.5 parts by weight (substantially 0.55 molecular proportion) of butylmercaptan and 20.7 parts by weight or 96.5% caustic soda (substantially 0.50 molecular proportion). The mixture was diluted somewhat with ethyl alcohol, cooled to 10 C. and 42.0 parts by weight (substantially 0.55 molecular proportion) 01 carbon disulilde added. The temperature rose to 28' C. The mixture was then stirred for about 12 hours without heating and 72.5 parts by weight (substantially 0.45 molecular proportion) of ortho chlor benzyl chloride added in a slow streamafter which the mixture was heated at refluxing temperature for about three hours. The alcohol was removed by distillation and the last traces stripped out by heating mildly under a vacuum. The residue was washed with water and dried leaving in good yield a reddish yellow liquid freely soluble in mineral hydrocarbon lubricating oils.

Exams: IV

Di (o-chlor beam/l) trithiocarbonate To a solution of 80 parts by weight (substantially 0.33 molecular proportion) of NaaS.9H:0

in substantially 400 parts by weight of methanol was added 27.8 parts by weight (substantially 0.37 molecular proportion) of carbon disulnde keeping the temperature below 30 C. The cold solution was stirred for several hours after which 107.3 parts by weight (substantially 0.67 molecular o-Ethyl S-trichlor benzyl monothiocarbonate The potassium salt of thio ethyl carbonate commonly known as Bender's salt (24 parts by weight or substantially 0.167 molecular proportion) was dissolved in substantially 200 parts by weight of ethyl alcohol. ,To this solution 38.5 parts by weight (substantially 0.159 molecular proportion) 01 trichlor benzyl chloride was added in a slow stream while keeping the temperature o: the reaction mixture at 20-25' C. Stirring was continued for several hours and the mixture allowed to stand for about 12 hours after which it was poured into an excess 01 water and the oil extracted with ether or other suitable solvent.

,The solventwas removed and the residue dried by heating at C. under good vacuum. A dark brown liquid was obtained in good yield.

. 7 Exam VI Trichlor benzyl diethyl dithiocarbamate chloride. Without heating, the reaction mixture was stirred for about five hours and the solvent then removed .byheating up to 40 C. under a good vacuum. The residue was washed with water, then dilute hydrochloric acid and finally with water again until neutral to litmus. The

washing of the oil is facilitated by dilution with' a suitable water immiscible solvent such as ether. After removal-of solvent, drying and filtering through. a bed or clay, a good yield of a brown viscous oil was obtained.

Exams: VII

Dichlor diethyl phem/l ethyl, ethyl :cantha'te Freshly distilled triethyl benzene was chlorinated at 75 C. in the presence of ultra violet light until the increase. in weight corresponded to that calculated for the introduction ot'one chlorine atom into each side chain. The chlorinated prodnot contained 40.1% chlorine by analysis. 186.0 parts by weight (substantially 0.7 molecular proportion) of the trichlor ethyl benzene so prepared was dissolved in substantially 238 parts by weight of acetone and the solution heated to refluxing temperature. Over a period of two hours 122.5 parts by weight'of 91.5% potassium ethyl tion) was added to the refluxing solution. Heating was continued for four hours, then the solvent removed, the residue washed with'water, dried and filtered through a bed or clay. An oily product was obtained in excellent yield and was soluble in mineral hydrocarbon oils.

. Exams: V111 42,4 dichlor phenyl) ethyl trithiocarbonate Substantially 209.5.parts by weight (substantially 1.0 molecular proportion) of a-(2,4-dichlor phenyl) ethyl chloride was added in a slow stream to a solution of substantially 86 partsby weight (substantially. 0.5 molecular proportion) of NazCSa in substantially 800 parts by weight of methanol. The mixture was stirred without heating for about an houraiter the chloride had been added and then heated to refluxing temperature for about six hours after which the sol-' vent was removed, preferably by distillation and the residue dissolved in a suitable water immiscible solvent, as for example benzene, andwashed with water. The solvent was again removed and the residue dried leaving in excellent yield a thin orange liquid soluble in hydrocarbon mineral lubricating oils.

CHLORINATION OF DIE'I'HYL BENZENE Chlorine was introduced into substantially 721 parts by weight of diethyl benzene at 90-110" C.

in the presence of ultra violet light. Samples were withdrawn corresponding to the di, iii,

tetra and penta chlorinated products. i'or chlorine gave the following:

Per cent orina Found Dichloride. an a 'lrlchloride.---. 46. 1 44. Tetraohloride 53. 2 52. Pentaohl ri n 50. 0 67.

The fractions so obtained inaiter described.

. g Exams: 1:: I Diichlor ethlll phenul emu! ti'ithiocdrbonate were reacted as here- Substantially 842 parts by weight (substantialiy 0.5 molecular proportion) of diethyl benzene dichloride was added slowly to a solution oi'isodium 'trithiocarbonate prepared by mixing '60 parts by weight or Na:S.9H:O (substantially 0.25

molecular proportion) and 38 parts byweight (substantially 0.50 molecular proportion) of carbon disulflde in substantially 200 parts by weight of methanol. The temperature rose to 34 C. dur- 'xanthate' (substantially 0.7 molecular propor-' ing the addition. Stirring was continued for four hours and the mass was then poured into'water and the oil dissolved in ether or other suitable solvent and dried. .4 red oil was obtained after removalof the solvent which was soluble in mineral hydrocarbon lubricating oils. Analysis for sulfur and chlorine indicated that the product was essentially di(chlor ethyl carbonate.

Exauru x Di(dichlor ethyl mm ethiilltrithiocarbonate Substantially 47.5 parts by weight (substantially 0.2 molecularproportion) of diethyl benzene trichloride'was added slowly to a solution of sodium trithiocarbonate prepared by mixing 24 parts by weight of Na:S.9HzO (substantially 0.1 molecular proportion) and 18.7 parts by weight (substantially 0.24 molecular proportion) of carbon disulflde in substantially 200 parts by I weight of methanol. Stirring was continued for four hours and the solvent removed as for ex-' I ample by distillation and the residue washed with -(substantially-0.24-molecular proportion) of carwater and dried. Substantially theoretical yield of a reddish oil was obtained which was freely soluble in mineral hydrocarbon lubricating oils.

- Analysis for sulfur and chlorine indicated the product was essentially di(dichlor ethyl phenyl ethyl) trithiocarbonate.

Exams: XI bfltrichlor ethyl pheni/l ethzlbtrithiocarbonate Substantially 54.5 parts by weight (substantially 0.2 molecular proportion) of diethyl benzene tetrachloride was added slowly to a solution of sodium trithiocarbonate prepared by. mixing 24 parts by weight oi 'NaaS.9HzO (substantially 0.1

molecular proportion) and 18.7 parts by weight bon disulfide in substantially 200 parts by weight oi. methanol. Stirring was continued for four hours and the solvent removed as for example by distillation and the residue washed with water and dried. Substantially theoretical'yield of a reddish oil was obtained which was moderately soluble in mineral hydrocarbon lubricating oils.

phenyl ethyDtrithio- Analysis product was essentially ethyl) trithiocarbonate.

Exmn:

for sulfur and chlorine indicated the di(trichlor ethyl phenyl by distillation'and the residue washed with water and dried. Substantially theoretical. yield of a reddish oil'was' obtained which was moderately I soluble in mineral hydrocarbon lubricating oils. v Exmrnr XIII Trichlor benzylester of bensothiolic acid Y The potassium salt of benzothiolic acid was.

prepared by saturating inthe cold an alcoholic solution of KOH with hydrogen sulfide and slowly adding benzoyl chloride to the cold solution containing an excess of KSH. The free acid was precipitated by the addition of hydrochloric acid and then purified by dissolving in aqueous KOH until alkaline to phenolphthalein and the solution evaporated. The salt was then dried at 100 C. Substantially 40 parts by weight of the salt so prepared (substantially 0.227 molecular-proportion) was suspended in substantially 237 parts by weight of alcohol and 47.1 parts by weight (substantially 0.205 molecular proportion) of trichlor benzyl chloride added in a slow stream. The

reaction was slightly exothermic. 7 After the addition of the trichlor benzyl chloride the mixture was heated to refluxing temperature for about three hours and the solvent removed. The residue was washed with water, preferably alter dissolving in a water immiscible solvent, then dried and the solvent removed leaving the desired ester as a residue. The product was soluble in mineral hydrocarbon oils. Analysis for sulfur and chlorine without further purification gave 9.2% sulfur and 33.8% chlorine as compared to calculated values of 9.7% sulfur and 32.1% chlorine.

weight approximated that calculated for trichlor V phenyl ethyl chloride.

Sodium ethyl xanthate was prepared by rearing below C. substantially'76 parts by weight (1.0 molecular proportion) of carbon disulflde, 36.6 parts by weight (substantially 0.88 molecular proportion) of sodium hydroxide and substantially 316 parts-by weight of ethyl alcohol. Substantially 1955 parts by weight (0.8 molecular proportion) of trichlor phenyl ethyl chloride was "added and the reaction mixture heated to refluxing temperature for about three hours. The excess alcohol was removed by distillation and the residue washed with water until neutral. Further purification, was eilected. by mildly heating under a vacuum and then filtering through a bed of clay. The trichlor phenyl ethyl ethyl xanthateso prepared was freely soluble in mineralhydrocarbon lubricating oils.

The effectiveness of the chloraralkyl esters of thio acids is demonstrated by the conventional tests on compositions comprised of these ingredients and a lubricating oil carrying agent. More specifically a minor amount or chloraralkyl ester was added to a high viscosity hydrocarbon lubricating oil (Saybolt Universal viscosity of 101 seconds at 210 F.) and samples or the blended lubricant subjected to the Almen Pin test described by Wolf and Mougey, Proc. A.'P. 1., 1932,

pages 118-130 and the S. A. E. test describedin S.- A. E. Journal 39, 23-4 (1936). These two tests are commonly accepted in the art as standards to determine the extreme pressure char-' acteristics of a lubricant.

In order for chlorine to eflectively improve the E. P. properties 01. organic sulfur compounds, it has generally been considered necessary that the chlorine be linked to an aliphatic radicle On the other hand, the results set forth in the table below demonstrate that in the case of the new adjuvants chlorine linked to the aromatic radicle markedly improves their eflectiveness. An admixture 01 benzyl butyl thiocarbonate and an Arochlor, which is the trade-marked name of chlorinated dlphenyl, was added to a mineral oil base and compared with the-same oil base containing trichlor benzyl butyl trithiocarbonate in amount such that the chlorine and sulfur content of the oil compositions were identical.

Team: I

Extreme pressure test.

1. failed Percent Percent Percent Product added I n S. A. E. (1000 in oil 8 oil l in oil R R M. 4:611 rubbing ratio; Almen 77-79 1 sJsec.

loading rate) Dibenryl trithioearbonate. 2. 85 Arochlur has; ass

Di(trichlorbenzyl) trithiocarbonate 7 .9 3.3 366 40 Benzyl diethyl dithioesrbamate 7 1.8 0.0 226 8 Trichlor benzyl diethyl dithiocarbamate 7 l. 3 2 2 328 40 EXAMPLIXIV Trichlor phenyl ethyl, ethyl :canthate Mono ethyl benzene was chlorinated at -80 C. in the presence of iron until th gain From the foregoing examples it will be seen that the chloraralkyl esters of this invention are highly efilcient extreme pressure lubricant bases and that the chlorine, although it may be linked in Weight .to the aryl group, markedly improves the eleccontaining the E. P. additive for 100 hours at 300 F, in open beakers. The viscosity of-the oil compositions was determined at 210 F. before and after heating and the increase in viscosity in percent calculated from the results obtained. A marked increase in viscosity indicates that viscous gummy constituents were formed as the result or oxidation and decomposition'of the "The foregoing examples bring out the fact that.

the presence or the chlorine actually seems to stabilize the oil compositions while at the same time improving the E. P. properties.

Other examples of the new lubricating oil compositions are set forth in Table III.

Tsar: III

, S. A. E. (1000 P t RIIPIhMJ 1:;611

ercen to re 0; m added inoil 17-101 ,lseo. loading rate), lbs. siled Di(chloro ethyl phenyl ethyl) trithiocarbona 9.3 360 Di(dichlor ethyl phenyl ethyl) trithiocar he 7.3 360 DKtrichlor ethyl phenyl ethyl) trithiocar n e a 6.4 310 Di(tetrachlor ethyl phenyl ethyl) trithim car he 6.9 360 Dichloro diethyl phenylvethyl. ethyl xanthate 10. 0 370 o-Etnyl S-trichlor benzyl monothiocarbonate l0. 0 313 Di(o-chlor benzyl) trithiccarbonate 7.0 340' iii-(2, dichlor phenyi) ethyl trithiocarbonate .10. O 354 Trichlor benzyl ester of benzothiolic acid 10.0 370 'Irichlor phenyl ethyl, ethyl xanthate-.. l0. 0 358 The above data show the high emclency of the new oil compositions; Obviously, other chlorar alkyl esters of thio acids can be used where convenient or desirable. Particular mention may be. made of (ll-(2,4 dichlor phenyl) ethyl, ethyl xanthate, di(methyl chlor benzyl) trithio'carbonate, dichlor phenyl ethyldiethyl dithiocarbamate,

trichlor phenyl ethyl methyl xanthate, trichlor phenyl ethyl amyl xanthate and the trichlor .phenyl ethyl ester of benzothiolic acid.

sure agent can be varied widely. Q The invention includes broadly the chloraralkyl esters of thio acids dissolved, dispersed or emulsified in any suitable carrying agent such as kerosene or other light petroleum hydrocarbons, benzene and other related hydrocarbons, alcohols, esters, ethers, fatty vegetable and animal oils as well as mineral hydrocarbon lubricating oils. This invention is limited solely by the claims attached hereto as part of the present specification, This applies.

tionds a division of co-pending ap lication Serial No. 540,891 filed June 17, 1944.

What is claimed is:

1. A chloraralkyl ester of a thio acid having a carbon atom of a chlor-aryl substituted alkyl chain not more than two carbon atoms in length linked to a member of a group consisting of sulfur and oxygen in turn linked to a member of the group consisting of-carbonyi and thiocarbonyl groups, the carbon atom-contained in said carbonyl group'being linkedjo at least one sulfur atom and the said chlor-aryl group containing less than five chlorine atoms.-

2. A chlor phenalkyl ester of a thio acid having a carbon atom of a chlor-phenyl substituted alkyl -'chain not more than two carbon atoms in length linked to a member of a. group consisting of sulfur-and oxygen in turn linked to a member of the group consisting of carbonyl and thiocarbonyl groups, the carbon atom contained in said carbonyl group being linked to at least one sulfur v atom and the said chlor-phenyl group containing l ss than five chlorine atoms. a

phenyl' group containing less than five chlorine atoms. 7

4. A chlor benzyl ester of a thio acid having at least one chlorbenzyl group containing less than five chlorine atoms linked to a member of a group consisting of sulfur and oxygen in turn linked to a member of a group consisting oi carbonyl and Again, the foregoing examples are to be taken thiocarbonyl groups, the carbon atom contained in said carbonyl group being linked to at least one sulfur atom.

5. A chlor benzyl thiocarbonate having at least one chlorbenzyl group containing less than five chlorine atoms linked to sulfur in turn linked to a member of a group consisting. of a carbonyl group and a thiocarbonyl group which is part of the said thiocarbonate group.

6. A chlor benzyl ester of a diallwl thiocarbamic acid having a chlorbenzyl group containing less than five chlorine atoms linked to a sulfur atom.

7. A chlor benzyl ester of a trithiocarbonic acid the chlorbenzyl group containing less than five chlorine atoms. 8. A compound of the type x t R-S- -x-n' where R is achlor substituted aralkyl radicle having an alkyl chain of not more than two carbon atoms and containing less than five chlorine atoms and R is an organic hydrocarbon group and X is a member of a group consisting of oxygen and sulfur.

9. A chlor benzyl ester a a dialkyl dithiocar- K 11. Acompound ct thetype 13. Trlchlor'benzyl 14. Trlchlor benzyl dlethyl dlthlccubamstc a chl dltlons ot'sl'de chain chlorlnatlon to introduce theequivalent of one stomp! chlorine. in the methyl group and reacting the product with en elkoll metal salt 01 e thlocarbonlc ecld.

EDWARD 8. mm 7