GB2193958A

GB2193958A - Preparing an extreme pressure (EP) additive for lubricants

Info

Publication number: GB2193958A
Application number: GB08619835A
Authority: GB
Inventors: Rezso Csikos; Sandor Borzsonyi; Peter L Farkas; Katalin Belafi; Zoltan Decsy; Gyorgy Barmos; Walter Szirmai; Janos Moger
Original assignee: Magyar Asvanyolaj es Foldgaz Kiserleti Intezet
Current assignee: Magyar Asvanyolaj es Foldgaz Kiserleti Intezet
Priority date: 1986-07-28
Filing date: 1986-08-14
Publication date: 1988-02-24
Anticipated expiration: 2006-08-14
Also published as: BE905181A; GB8619835D0; NL8601965A; GB2193958B; FR2602785B1; FR2602785A1; CH675121A5

Description

1 GB2193958A 1

SPECIFICATION

Process for preparing an extreme pressure (EP) additive This invention relates to a process for the preparation of an extreme pressure (EP) additive with 5 a high sulfur content, useful for the production of auxiliary materials for lubricating and hydraulic oils, lubricating greases as well as for metal-working coolant and lubricating fluids.

For preserving vehicles, engines, industrial equipment, hydraulic systems as well as tools and equipment in metal-working processes, for diminishing the wear and for a more economical operating, lubricating materials are at present prepared with an EP additive of 0. 1 to 20% by 10 mass. These compounds containing in general sulfur, chlorine, phosphorus or nitrogen go into chemical reactions with the metals resulting in a superficial protective layer which inhibits the formation of local welded microbonds caused by heat flashes of high temperature appearing as a consequence of high loads between metal surfaces moving on each other. The splitting of these microbonds gives rise to the development of superficial pitting or striation. In addition to the 15 wear-resistant properties, other important characteristics such as lubricating capacity, heat stabil ity as well as protective action against oxidation and corrosion of the lubricating materials should also be considered. These are taken into account by adding compounds with a combined effect, on the one hand, and additive compositions, on the other hand.

A high number of processes for preparing EP additives have been reported in the literature, 20 especially in the patent specifications involving EP additives. These processes can be divided to three well-distinguishable groups.

1) The reaction of alkanols, esters, alkylphenol derivatives, olefines and/or hydrocarbons con- taining sulfur, chlorine or nitrogen as heteroatoms with the sulfur compounds of phosphorus, e.g.

with PAO: 25 Processes of such type are described e.g. in the East-German patent specifications Nos.

117,248, 101,695 and 79,093, in the United States patent specification No. 4,058,468 as well as in the Hungarian patent specification No. 180,272. Though the EP effect of the thus-prepared additives containing mainly sulfur and phosphorus is weak, their additional action is yet advan tageous with a preferable antioxidant and corrosion-inhibiting effect. 30 2) The reaction of alkenes containing one or more unsaturated bonds, aromatic and/or alkylar- ornatic hydrocarbons, hydrocarbons containing sulfur, chlorine, nitrogen or phosphorus as hetero atoms and esters with the chlorine compounds of sulfur (e.g. with SC121 S2021 SOC12 or R-S-C 1): - In some cases, the reaction product is subjected to a post-treatment with an alkali metal 35 hydroxide, sodium mercaptide or sodium sulfide in order to eliminate the residual chlorine content.

Processes of such type have been described in the United States patent specifications Nos.

4,198,305, 4,097,387, 3,925,414, 3,844,964 and 3,873,454 as well as in the French patent specification No. 2,404,042. These processes are used for the preparation of EP additives with 40 medium or high sulfur content and containing in general also other heteroatoms.

3) The reaction of olefines containing one or more unsaturated bonds, esters, hydrocarbons containing heteroatoms with elementary sulfur or with the mixture of elementary sulfur and hydrogen sulfide in the presence of or without a catalyst:

The direct sulfuration of isobutylene or C,, olefines is most frequently used. Processes of 45 such type have been reported in the French patent specification No. 2,434, 864, in the United

States patent specifications Nos. 3,926,822, 3,899,475, 4,119,550 and 4, 119,545 as well as in the German patent specification No. 2,838,981. These processes are useful for the prepara tion of additives with a high EP effect containing 5 to 50% of sulfur. The drawbacks of this method of preparation consist in the relatively high pressure (100 bar), in the relatively high 50 temperatures (150 to 2000C) as well as in a high amount of harmful side- products causing environmental pollution.

In the course of our investigations concerning EP additives it has been recognized that EP additives of the general formula, 551? (RI-vArb)c(Sx)d wherein R1, 1311, R"', R'v and Rv are the same or different and each represents a hydrogen atom, a C,-,,) straight or branched chain or cyclic, saturated and/or unsaturated hydrocarbyl group and/or a derivative thereof; 60 Ar stands for a monocyclic and/or polycyclic aromatic hydrocarbyl group and/or a derivative thereof; b means an integer from 0 to 5; c means an integer from 2 to 10; d means an integer from 1 to 9; and 65 2 GB2193958A 2 x means an integer from 1 to 6,with a high sulfur content and higher effectivity can be prepared in a much simpler way and with lower expenditures than described in the above mentioned processes, by reacting an organic halogen compound of the general formula (RI-v-Ar,)-X,, 5 wherein RI, R", 13111, RIv, Rv, Ar and b are the same as defined above, X means a halogen atom and "a" stands for an integer from 1 to 5, with a compound of the general formula MA, 10 wherein M represents an alkali metal and/or alkali earth metal and n means an integer from 1 to 2, in a mixture of alcohol, water and a weakly polar solvent, and after termination of the reaction separating the phase containing the product and purifying it by removing the solvent and by clarification. 15 The quality of the thus-prepared product, such as the composition, the total and so-called active sulfur content, solubility, heat stability, and tribological properties thereof, is ensured according to the individual fields of utilization by the suitable selection of the composition of the starting organic halogen compound as well as of the n:x ratio in the MnSx metal sulfide partici pating in the reaction and by the purifying operations. 20 According to the process of the invention, the dialkyl and/or bis- and/or tris-(alkylaryl)-sulfides and/or polysulfides having an advantageous wear-diminishing effect are prepared in such a way that the alkali metal sulfide and/or alkali earth metal sulfide, preferably sodium sulfide, together with elementary sulfur, establishing the S. group to be built-in into the organic molecule, are dissolved in a solvent mixture containing 0 to 100 parts by mass of an alkanol, preferably 50 to 25 parts by mass of ethanol, 0 to 50 parts by mass, preferably 10 to 30 parts by mass, of water and 0 to 50 parts by mass of a weakly polar solvent, preferably 0 to 20 parts by mass of toluene and/or xylene at a temperature below the boiling point of the alcohol, suitably at a temperature from 65'C to 75'C. Thereupon, an alkyl and/or alkylaryl halide is portionwise added to the reaction mixture in an amount calculated for an excess of Na-I suitably of at least 10%, 30 then the reaction mixture is stirred at 50 to 60'C until the reaction becomes complete. Then, the mixture is cooled to the temperature of the cooling water (15 to 25'C), whereupon the mixture separates to two liquid phases and a solid one.

On establishing the composition of the solvent mixture used for dissolving the sodium sulfide, three important view-points should be considered: 35 -the sodium sulfide should readily be dissolved in the solvent mixture; -the reaction should proceed with an appropriate rate; -after the termination of the reaction, the product should be obtained in a separate phase to be easily separated from the alcoholic phase and from the impurities dissolved therein.

The above three view-points are accomplished as follows: 40 -the solubility of sodium sulfide is increased by introducing an appropriate amount of water; -the desired rate of the reaction proceeding on the phase limit is achieved by a suitable selection of the ratio of water, alcohol and the weakly polar solvent; -the good separability of the product in a separate phase after proceeding of the reaction is A improved to a high extent by introducing a weakly polar solvent. 45 As the weakly polar solvent has first of all to be introduced for the last reason, it is obvious that this solvent has not to be added by all means to the solvent mixture used for dissolving. the sodium sulfide, but it can be introduced simultaneously with the alkyl and/or alkylaryl halide, possibly dissolved in these compounds and/or after the conclusion of the reaction.

After termination of the reaction, the product as dissolved in the weakly polar solvent can in 5Q general be found in the lower phase, whereas little amounts of the dark- coloured, harmful side products arising from the decomposition and polymerisation reactions and the unreacted M,,S., are contained in the upper aqueous-alcoholic phase. The separation of these layers is essential concerning the quality of the product, since the product reacts with the above substances at 120 to 140C used in the course of the further operations of purification and removal of the 55 solvents, whereby the colour of the product becomes darker with deterioration of the quality.

The aqueous-alcoholic phase recovered from the upper phase may be reutilized as a solvent mixture for a following production process after supplementing the losses.

Thus, the separation of the product-containing phase from the aqueousalcoholic phase should be considered as an essential step of the purification, which is made more effective by the 60 selection of a suitable amount of the weakly polar solvent as well as by cooling.-Then, the solid sodium chloride formed in the reaction is removed by filtration. Subsequently, a little amount of an alcoholic phase generally appears which is repeatedly and carefully separated.

As the final step of the purifying operation, the product is made ftee from the solvents by distillation, then clarified by adding a little amount of a clearing aid (preferably bleaching earth or 65 3 GB2193958A 3 filter-perlite) and then freep from the sediments by filtering.

The quality such as the oil-solubility, heat stability, corrosion properties and EP effect of the thus-prepared organic polysulfide are defined in the composition of the product by the structure of the hydrocarbyl group and by the average value of x in the S. group bound to the hydrocar byl group. 5 The solubility and heat stability of the additive increases in parallel with the increase of the molecular mass of the hydrocarbyl group. The oil-solubility of organic polysulfides containing an aromatic group is generally lower, but this can be improved by increasing the number and molecular mass of the alkyl substituents bound to the aromatic ring.

The heat stability of the organic polysulfides containing an alkylaromatic group, which is 10 determined by a derivatographic examination under air atmosphere, has been proved to be higher than that of the alkyl polysulfides, and this heat stability increases with the increase in the molecular mass of the hydrocarbyl group. The heat stability of the additive of the invention is higher as a consequence of the more uniform composition and higher purity of the product.

In the course of working out the process of preparing the above-described organic polysulfides 15 it has also been recognized that, in the S,, group introduced to the molecules of the product, the proportion of the so-called active sulfur content within the total sulfur content in increased with the increase in the value of x. The active sulfur content means the sulfur quantity which is able to react with copper metal. This value can quantitatively be determined according to the pres criptions of the standard ASTIVI D-1662. 20 The active sulfur content of the EP additive is important from the view- point of corrosion properties of the product, as polysulfides having a higher active sulfur content are more corro sive mainly against copper. The extent of the corrosion of copper is qualified according to the standard ASTM D-130.

In case of several products such as particularly in case of EP additives of auxiliary materials of 25 metal-working coolant-lubricating fluids, a high active sulfur content is pronouncedly advan tageous in view of the wear-diminishing effect, whereas the corrosion properties are less impor tant from the view-point of the nature of the use.

As the value of x in the S,, group introduced into the product can be altered as desired by selection of the composition of the M,Sx metal polysulfide, a possibility exists to vary also the 30 active sulfur content of the product to an optional extent. On the basis of investigations on the corrosion and on the EP effect, it has been stated that such organic polysulfides can only be used for preparing lubricating and hydraulic oils, the active sulfur content of which is not higher than 50% of the total sulfur content. This condition can be satisfied by a value of x from 1 to 4, whereas in the EP additives of auxiliary materials of the metal- working coolant-lubricating 35 fluids, at least 40% of the total sulfur content should be present in the form of an active sulfur content. This latter condition can be accomplished when the value of x is at least 3.

Several methods are known which are useful for qualifying the EP effect of the additive, some of which are to be found in the standards DIN 51, 350, ASTIVI D 2266-67 and ASTIVI D 2783-69 T. 40 It has been proved by qualifying tests carried out on organic polysulfides that the preferable EP effect is provided not only by the quantity of the sulfur introduced to the lubricating material but the organic group bound to the sulfur also plays an important role in this effect. Accordingl, it can be established that the EP effect of polysulfides containing an aromatic hydrocarbyl group is in general higher. 45 It has also been proved by the examination of the EP effect that the effectivity of the product is also influenced by the manufacturing technology of the organic polysulfide. Based on the results of the four-ball and FZG tests, the effectivity of the more uniform product with a higher purity prepared according to the process of the invention is higher than that e.g. of the product obtained by the direct sulfuration of isobutylene. 50 The invention is further illustrated by the aid of the following non- limiting Examples.

Example 1

1476.2 g (65 parts by mass) of ethanol, 492.1 g (22 parts by mass) of water and 300 g (13 parts by mass) of xylene are introduced into a heatable and coolable round-bottom flask fitted 55 with a stirrer, thermometer and reflux condenser. The stirring is started and a solvent mixture is prepared by homogenizing the system. Then the solvent mixture is heated to 75'C, and 340 g of an industrial grade sodium sulfide of 70.5% purity are portionwise added to the system and dissolved by stirring for one hour. The thus-obtained sodium sulfide solution having a concentra tion of about 10.7% is cooled to 50'C and 900 g of dimethylbenzyl chloride are added in 60 several portions through a feeding funnel under pressure during one hour while the heat released is dissipated by cooling. Thereafter, the mixture is stirred for 2 hours, then cooled to the temperature of the cooling water (18oC) and the stirring is stopped. After standing for one hour, the mixture separated to two liquid phases. The upper alcoholic phase is drained off, whereas the lower phase containing the product is made free from the solid sodium chloride by filtering. 65 4- GB2193958A 4 The xylene solution of the product is subjected to distillation under reduced pressure for removing the solvent, then 4 g of bleaching earth are added to the residue, and after clarification the product is purified by filtering through a filter paper to give the product in a yield of 746 g with a sulfur content of 11.6%. The number of the sulfur atoms in the molecule, i.e. the value of x is about 1. 5 Example 2

The process described in Example 1 is followed, except that the mixture of ethanol, water and xylene containing 10.7% of sodium sulfide is cooled to 60'C and then 98.5 g of powdered elementary sulfur are added to the mixture which is then stirred until complete dissolution (about 10 one hour). Thereafter 900 g of dimethylbenzyl chloride are portionwise added and then the process described in Example 1 is followed. The product is obtained in a yield of 835.6 g with a sulfur content of 21.0%. The average number of the sulfur atoms in the molecule, i.e. the value of x is about 2.

15 Example 3

The process described in Example 2 is followed, except that 295.4 g of sulfur powder are used. The product is obtained in a yield of 1012 g with a sulfur content of 34.5%. The average number of the sulfur atoms in the molecule, i.e. the value of x is about 4.

20 Example 4

The process described in Example 2 is followed, except that 492.4 g of sulfur powder are used. The product JS obtained in a yield of 113.2 g with a sulfur content of 42.3%. The average number of the sulfur atoms in the molecule, i.e. the value of x is 5.7.

25 Example 5

The process described in Example 3 is followed, except that, instead of dimethylbenzyl chloride, an equivalent amount of ethylbenzyl chloride is added to the Na2S4 solution. The product is obtained in a yield of 1008 g with a sulfur content of 34.9%. The average number of the sulfur atoms in the molecule, i.e. the value of x is about 4. 30 Example 6

The process described in Example 3 is followed, except that, instead of dimethylbenzyl chloride, 900 g of an isomeric mixture consisting of dimethylbenzyl chloride and ethylbenzyl chloride are added to the solution of Na2S4. The product is obtained in a yield of 1002 g with a 35 sulfur content of 34.1%. The average number of the sulfur atoms in the molecule, i.e. the value of x is about 4.

Example 7

The process described in Example 6 is followed, except that no xylene is added to the solvent 40 used for dissolving the sodium sulfide. The 300 g amount of xylene together with the solution containing 900 g of dimethylbenzyl chloride and ethylbenzyl chloride are added to the reaction mixture. The produdt is obtained in a yield of 1003 g with a sulfur content of 34.8%. The average number of the sulfur atoms in the molecule, i.e. the value of x is about 4.

45 Example 8

The process described in Example 6 is followed, except that no xylene is contained in the solvent used for dissolving the sodium sulfide. The 300 g amount of xylene are added to the reaction mixture after taking place of the reaction. The product is obtained in a yield of 1040 g with a sulfur content of 34.2%. The average number of the sulfur atoms in the molecule, i.e. the 50 value of x is about 4.

Example 9

The process described in Example 7 is followed, except that 1720.8 g of dodecylbenzyl chloride are used as an alkylaryl halide. Further on, the process described in Example 7 is 55 followed. The product is obtained in a yield of 1870 g with a sulfur content of 19.3%. The average number of the sulfur atoms in the molecule, i.e. the value of x is about 4.

Example 10

The process described in Example 7 is followed, except that 1267 g of a mixture obtained by 60 chloromethylating xylene and containing 32 parts by mass of xylene, 63 parts by mass of an ethylbenzyl chloride and dimethylbenzyl chloride mixture and 5 parts by mass of dimethyl bi s(chloromethyl) benzene are used as alkylaryl halide. The starting material also contains xylene, so no weakly polar solvent is separately added. An other difference of this process consists in that 197 g of elementary sulfur are introduced. Thereafter the process described in Example 7 is 65 GB2193958A 5 followed. The product is obtained in a yield of 907 g with a sulfur content of 28.2%. The average number of the sulfur atoms in the molecule, i.e. the value of x is 3. The colour of the product is yellow.

Example 11 5

The process described in Example 10 is followed, except that 393 g of elementary sulfur are used. The further steps of the process are the same as described in Example 10. The product is obtained in a yield of 1056 g with a sulfur content of 40.3%. The average number of the sulfur atoms in the molecule, i.e. the value of x is about 5. The colour of the product is yellow.

10 Example 12 (Example 1 for comparison) The process described in Example 11 is followed, except that after termination of the reaction the phases are not separated, but the mixture is made free from the solvents by distillation, then the residue is clarified with 5 g of bleaching earth and thereafter filtered. The product is obtained in a yield of 1083 g with a sulfur content of 41.7% and with a chlorine content of 0.8%. The 15 colour of the product is black with an unpleasant, intensive, stinging odour.

Example 13

The process described in Example 2 is followed, except that as a weakly polar solvent benzene is used instead of xylene and 538.5 g of tertiary-butyl chloride are added as halogen 20 compound. The other steps of the process are the same as described in Example 2. The product is obtained in a yield of 170.2 g with a sulfur content of 37%.

Example 14

The process described in Example 13 is followed, except that 700 g of allyl bromide are used 25 in the reaction. The product is obtained in a yield of 420 g with a sulfur content of 44%.

Example 15

The process described in Example 13 is followed, except that 1122.9 g of octyl bromide are added as halogen compound to the solution of Na,S,. The product is obtained in a yield of 400 30 g with a sulfur content of 22.8%.

Example 16

The process described in Example 3 is followed, except that instead of sodium sulfide 338.7 g of potassium sulfide of analytical purity are added to the solvent mixture. The other steps of 35 the process are the same as described in Example 3. The product is obtained in a yield of 1017 9 with a sulfur content of 34.7%.

Example 17 (Example 2 for comparison) For comparison, according to the German patent specification No. 2,838, 981, 526 g of sulfur 40 powder, 920 g of cooled liquid isobutylene and 269 g of cooled liquid hydrogen sulfide are introduced into a high-pressure reactor fitted with a stirrer, heating jacket and condenser coil.

After closing the reactor, the mixture is heated to 170'C while stirring. The pressure rises to 92 bar. The reaction mixture is stirred for about 10 hours whilst the pressure gradually decreases below 20 bar. Then, the reactor is cooled to room temperature and the thus-obtained dark 45 reddish-brown liquid is poured into a distilling flask. After removing the unreacted materials by distillation and after clarification as well as other purifying operations, a product is obtained in a yield of 760 g with a sulfur content of 42.5%.

The data obtained in the quality and effectivity examinations of the EP additive samples prepared as described in the Examples are as follows. 50 A) The EP effectivity of the samples was qualified as mixed in a concentration of 6.5% to a drive base oil with a viscosity classified as SAE-80 W-90 by using a four- ball tester. The heat stability of the compounds was investigated by using derivatography under atmospheric condi tions. The total sulfur content (ST) of the prepared samples was determined by using Sch6niger's method, the active sulfur content (SA) was measured according to the prescriptions of the 55 standard ASTIVI D-1662, whereas the copper corrosion examinations were carried out according to the prescriptions of the standard ASTIVI D-130. The results are given in the following Table.

B) The EP additive prepared by using the process described in Example 10 was mixed in a half proportion to a mixture consisting of anti-oxidant, detergent, dispersing and corrosion inhibiting additives to give an EP additive composition. This composition was added in an 60 amount of 0 to 6.5% to a drive base oil with a viscosity classified as SAE-80 W-90 and the value of the welding load was determined by the four-ball test carried out according to the standard DIN 51,350. The results of the test are shown on curve I of the Figure enclosed. On the horizontal axis of the diagram, the concentration in % of the additive, whereas on the vertical axis the value of the total welding load in N were plotted. The quality level API-GL-5. 65 6 GB2193958A 6 defined in the international prescriptions can- be achieved by adding the additive in an amount of as low as 3% by mass. Here, the value of the welding load was 4000 N.

C) For comparison, an EP additive composition was prepared as described under B) by using the EP additive prepared as described in Example 17. By using this additive composition, drive oils containing various amounts of the composition were prepared. The results of the four-ball 5 test carried out in an identical manner are shown on curve 11 of the Figure. In this case, the welding load value of 4000 N could be achieved by using the additive composition in an amount of 6.5 %.

D) An FM test (type number A/16, 6/90/10) according to the standard DIN 51,354 was carried out on a drive oil prepared with an amount of 6.5% of the EP additive composition as 10 described under B). A deterioration grade number higher than 12 and a specific mass change of 0.032 mg/MJ were obtained.

E) The examination described above under D) was carried out on an EP additive composition prepared as described above under C). On using this additive composition in an amount of 6.5% 4 by mass, a deterioration grade number of 12 and a specific mass change of 0.122 mg/MJ were 15 observed.

F) The EP additive prepared as described in Example 11 was mixed in an amount of 3% to a coolant-lubricating fluid also containing wear-improving and corrosion- inhibiting additives. Thus, the value of the total welding load was increased from 1600 N to 5000 N.

Table

E N-ample o m p o u n d Sulfur content Colour Heat Four-ball test, Copper of the stability total weldin.- corrosion S T S, A S A -1c, T produCt load AS11.1 Start- Final ASIN ing temp. D-130.

Union temp.

Oc 0 c 1 bis (Dimethylbenz-.%-l)sulfide 11.6 0.6 5.2 2 150 550 4000 1 b 2 bis (DimethvIbenz'N I)disulfide 21.0 3-3 15.- 2 16o 550 5000 1 b 3 bis(Dimeth-5-lbenzyl)tetrasulfide 34.5 19.8 57.4 3 Igo 550 6,;oo 4 a 4 bia(Dimeth)-lbenzyl)llexasulfide 42.3 31.0 73.3 3 Igo 550 7000 4 c bis(Ethylbenz3-I)tetrasulfide 34.9 ig.6 56.2 3 Igo 550 65oo 4 a 6 Mixture of bis(dimethylbenzyl) -tetrasulfide and bis(ethylbenzyl) -tetrasulfide isomers 34.1 20.2 59.2 3 190 550 6500 4 a 7 Mixture of bia(dimeth-vlbenzv.L) -tetrasulfide and bis(ethyLbenzyl) -tetrasulfide isomers 34.8 20.0 57.5 3 190 550 65oo 4 a 8 Mixture of b1s(dbmethv1benz-%1I)- G) -tetrasulfide and bis(ethvlbenz-vl) -tetrasulfide isomers 34.2 19.7 57.6 3, 190 550 6e;oo 4 a CD Ln 00 00 Table (contd.) Example C o m p o u n d Sulfur content 1,t Colour Heat Four-ball test, Copper No. of the stability total welding corrosion S T S A S A/ST product load ASTM Start- Final ASTM ing temp. N D-130 union temp.

0 C 0 C 9 bia(Dodecylbenzyl)-tetrasulfide 19.3 LO.2 52.6 4 220 550 5300 3 b Isomeric mixture of bis(alkyl- aryl)-trisulfides 28.2 12.8 45.4 4 Igo 550 6ooo 3 a Ll Isomeric mixture of bis(alkyl aryL)-pentasuLf idea 40.3 27.9 69.2 4 Igo 550 7000 4 c 12 Isomeric mixture of bis(alkyl a ryl)-pentasuLf ides 41.7 29.5 70.7 8 16o 550 65oo 4 0 13 di-tertiary-Butyl-disulfide 37.0 15-t 4o.7 2 70 2-10 420 1 b 14 Diallyl-disulfide 44.o 17.3 47.3 3 6o 250 4000 1 b L5 Dioctyl-disulfide 22.0 8.3 37-7 3 ISO 45o 4200 1 b 16 bia(Dimethylbenz)-L)-tetrasuLfide 34.7 20:1 57.9 3 Igo 550 7000 4 a 17 di-tertiary-But)-t-disulfide 42.5 17.6 41.3 5 -10 270 3800 2 b CD (A) (0 01 00 CO A;.

9 GB2193958A 9

Claims

1. 1. A process for the preparation of an extreme pressure (EP) additive of the general formula (R1-v-Arb)c(Sx)d 5 wherein R', R", 13111, R1v and Rv are the same or different and each represents a hydrogen atom, a C,-,, straight or branched chain or cyclic, saturated and/or unsaturated hydrocarbyl group and/or a derivative thereof; Ar stands for a monocyclic and/or polycyclic aromatic hydrocarbyl group and/or a derivative 10 thereof; b means an integer from 0 to 5; c means an integer from 2 to 10; d means an integer from 1 to 9; and x means an integer from 1 to 6; 15 by reacting an organic halogen compound of the general formula (R1-v-Arb)_Xa wherein R', R', 13111, R'v, Rv, Ar and b are the same as defined above, X means a halogen atom 20 and "a" stands for a number from 1 to 5, with a metal sulfide of the general formula, MnS wherein M represents an alkali metal and/or alkali earth metal and n means an integer from 1 25 to 2, together with elementary sulfur, which comprises first reacting the compound of the general formula MnS with elementary sulfur in a mixture consisting of 0 to 50 parts by mass of water, 0 to 10 parts by mass of alcohol and 0 to 50 parts by mass of a weakly polar solvent introduced into the reaction mixture before and/or after the polysulfide- forming reaction, then reacting the solution of M,,S,, with the organic halogen compound of the general formula (R,-- 30 v-Arb)_Xa and adjusting the value of x in the S. group to a value from 1 to 4 by varying the composition Of MA and thus adjusting the value of the active sulfur content to not more than 50% by mass, then separating the thus-obtained product from the unreacted MA and from the impurities arising from side-reactions being present in a separate phase after the reaction, then making free the thus-obtained product from the sediments, optionally making free it from the 35 solvents and purifying it.

2. A process as claimed in claim 1, which. comprises dissolving sodium sulfide in a solvent mixture consisting of 50 to 80 parts by mass of ethanol, 10 to 30 parts by mass of water and 0 to 20 parts by mass of xylene and/or toluene and/or benzene.

3. A process as claimed in claim 1 or 2, which comprises adding the weakly polar solvent to 40 the reaction mixture together with the organic halogen compound of the general formula (R'- v-Arb)-Xa or after taking place of the reaction.

4. A process as claimed in any of claims 1 to 3, which comprises using benzyl chloride, o-, Z rn- or p-methylbenzyl chloride, o-, m- or p-ethylbenzyl chloride or an isomeric mixture prepared by chloromethylating xylene and containing xylene, climethylbenzyl chloride and dimethyl-bis(chlo- 45 romethyl)-benzene or dodecylbenzyl chloride, tertiary-butyl chloride, allyl bromide or octyl bro mide as a compound of the general formula (R'-Arb)_Xa

5. A process as claimed in any of claims 1 to 4, which comprises, after proceeding of the reaction, cooling down the mixture, separating the two phases obtained after standing, separat ing soldiurn chloride by filtration from the commonly lower phase containing the product and 5Q then repeatedly separating the alcoholic phase appearing in a little amount.

6. A process as claimed in any of claims 1 to 5, which comprises dissolving the sodium sulfide and thereafter dissolving the sulfur at 65 to 75'C, carrying out the reaction at 50 to 60'C and separating the phases at a temperature not higher than 25'C.

7. A process as claimed in any of claims 1 to 6 for the preparation of extreme pressure (EP) 55 additives for lubricating and hydraulic oils, which comprises introducing the sodium sulfide and elementary sulfur reactants in such a ratio for the polysulficle-forming reaction as to adjust the value of x to 2 to 4 in the Na2SX compound and thereby adjusting the active sulfur content to a value not exceeding 50% by mass of the total sulfur content in the product.

8. A process as claimed in any of claims 1 to 6 for the preparation of auxiliary materials for 60 metal-working coolant and lubricating fluids, which comprises introducing the sodium sulfide and elementary sulfur reactants in such a ratio for the polysulfide-forming reaction as to adjust the value of x to at least 3 in the Na2Sx compound and thereby adjusting the active sulfur content to a value of at least 40% by mass of the total sulfur content in the product.

9. A process as claimed in any of claims 1 to 8, which comprises removing the weakly 65 GB2193958A 10 polar solvent by distillation and purifying the crude product made free from solvents by clarifying with 0.2 to 1% of bleaching earth and by filtering.

10. A process as claimed in any of claims 2 to 8, which comprises, after supplementing the losses, re-utilizing the aqueous-alcoholic phase, commonly obtained in the upper phase on separating the phases after termination of the reaction and cooling down the reaction mixture, in 5 a following production process for dissolving the sodium sulfide.

11. A process of preparing an extreme pressure additive of the general formula (RI-v-Arb)c (SI 10 wherein RI to Rv, Ar, b, c, x and d are as defined in claim 1 which comprises reacting a compound of the general formula (RI-v-Ar,)-Xa 15 where R", Ar and b are as defined above with a stoichiometric or non- stoichiometric alkali metal or alkali earth metal sulfide of the general formula MnSx 20 where M stands for an alkali metal or an alkaline earth metal, n is 1 or 2 and x is as defined above in the presence of a solvent comprising 0-50 parts by weight of water, 0parts by weight 25 of an alcohol, 0-50 parts by weight of a weakly polar solvent, separating the thus-obtained product from unreacted MnSx, from the products (if any) of side reactions, and from sediments and optionally removing the solvent and optionally purifying the product.

12. A process of making an EP additive substantially as hereinbefore described in any one of Examples 1 to 11 and

13 to 16. 30 13. An EP additive obtained by a process as claimed in any one of claims 1 to 12.

14. Lubricating or hydraulic-oil, lubricating grease, metal working coolant or lubricating fluid or an additive therefor containing an EP additive as claimed in claim 13.

Published 1988 at The Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.

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