NL8601966A - PROCESS FOR PREPARING EP ADDITIVES. - Google Patents

Description

é · NL 33650-dJ / cs i

Process for the preparation of EP additives.

The present invention relates to a process for the preparation of a high-sulfur EP additive which is suitable for the preparation of lubricating and hydraulic oils, lubricating greases as well as lubricating and cooling fluids usable in metalworking, from chloromethylated alkyl aromatic connections. The abbreviation EP here stands for Extreme Pressure or extreme pressure.

Lubricants suitable for vehicles, power equipment, industrial plants, hydraulic systems and metalworking are used for the protection of tools and equipment, for the reduction of wear and in the interest of an economic operation, often by 0.1-20% EP additive prepared. These generally sulfur, chlorine, phosphorus and nitrogen-containing compounds form a chemical reaction with the metals, whereby a protective layer is formed on the surface, which prevents the formation of local micro-welded connections between the metal surfaces that move against each other. Such micro welding connections are caused by the high temperature heat flashes occurring under high load; if they break, pitting or grooves are formed on the surface. In addition to the protective effect against abrasion, other important properties, such as the lubricating power, heat stability, protection against oxidation and corrosion must also be taken into account. These properties are achieved in part by compounds with a combined action, in part by additive compositions.

Numerous processes for the preparation of EP additives have been described in the literature on lubricants, in particular the patents, which can be divided into three easily distinguishable groups.

1) Conversion of alkanols, esters, alkylphenol derivatives, olefins and / or sulfur, chlorine, nitrogen as hetero-atoms containing hydrocarbons with phosphorus-sulfur compounds, for example with 1% (e.g. the DDR) U.S. Pat. Nos. 117 248, 101 695, and 79 093, U.S. 860186, U.S. Patent 4,058,468, and Hungarian Patent No. 180,272). Although a sulfur and phosphorus-containing additive prepared in this way is only slightly effective as an EP additive, it has favorable additional properties, for example a protection against oxidation and corrosion.

2) One or more unsaturated bonds containing olefins, aromatic and / or alkyl aromatic hydrocarbons, sulfur, chlorine, nitrogen, phosphorus hetero atoms containing 10 hydrocarbons, esters with the chlorine compounds of sulfur (SC ^, S2CI2, SOCI2 or RS-Cl) converted. In many cases, the reaction product is post-treated with sodium hydroxide, sodium capaptide or sodium sulfide to remove the residual chlorine content. Such methods are described in U.S. Pat. Nos. 4 198 305, 4 097 387, 3 925 414, 3 844 964 and 3 873 454 and in French Pat. 2 404 042. The end products are generally medium or high sulfur content EP additives, which usually also contain other heteroatoms.

3) One or more unsaturated bonds containing olefins, esters, heteroatoms containing hydrocarbons are reacted with elemental sulfur or elemental sulfur and hydrogen sulfide, optionally in the presence of a catalyst. Most commonly used is the direct sulfurization of isobutylene or Cg-Cg olefins. Such methods are described in French Pat. No. 2,443,864, U.S. Pat. Nos. 3 926 822, 3 899 475, 4 119 550 and 4 119 545 as well as in German patent 2 838 981. Using these methods, highly effective EP additives containing 5-50% sulfur can be prepared. The disadvantage of this is that it is necessary to work under a comparatively high pressure (100 bar) and at high temperatures (150-200 ° C) and that environmentally harmful substances are formed as a by-product. significant amount of.

In studies conducted in the preparation of EP additives, it has now been found that highly effective EP additives of the general formula (R1 V-Ar ^) (Sx) ^ are substantially simpler and less expensive can be prepared. The subject of the 8601966 9 - 3 -

The invention is therefore a process for the preparation of EP additives of the general formula <R1'V-Arb> c (Vd wherein

I II V

5 R, R ... R independently represent hydrogen, straight or branched chain or cyclic, saturated or unsaturated hydrocarbon groups having 1 to 40 carbon atoms or derivatives thereof, and the groups 10 Ar independently of one or more ring aromatic hydrocarbons or represent derivatives of such groups, b is a number 1-5, c is a number 2-10, d is a number 1-9, and x is a number 1-6.

In the process according to the invention, hydrocarbons of the general formula R1 V-Arb with a formaldehyde solution and / or paraformaldehyde and aqueous hydrochloric acid and / or hydrogen chloride gas are optionally chlorinated in the presence of a catalyst and the resulting alkylaryl chloride is treated with sodium polysulfide converted.

As has been demonstrated by extensive technological studies and performance analyzes, the quality parameters of the organic polysulfides, for example solubility in lubricating oils and organic solvents, compatibility with other additives, tribological properties depend decisively on the composition of the chloromethylation obtained product. Namely, no univocal substance is formed in this step, but immediately after the reaction has started, di- and optionally poly-substituted compounds are formed in addition to the monosubstituted compound. This process is shown in reaction schemes A) and B).

Due to the laws of the reactions of alkyl aromatic hydrocarbons and as a result of the reaction inhibiting effect of the 8601966 - 4 - -OE-Cl group attached to the aromatic ring, the reaction rate is slower when a further methyl chloride group enters and the probability of entering a third methyl chloride group is negligible in a large proportion of all cases.

The invention will now be further elucidated with reference to the annexed drawings.

Fig. 1 shows the composition of the product obtained by the chloromethylation of a xylene isomer mixture as a function of the total chlorine content of the product (for 35 ° C and 50 ° C).

Fig. 2 shows the composition of the organic polysulfide as a function of the ratio between mono and dichlorinated compounds.

In Fig. 1 the total chlorine content is plotted on the abscissa in weight percent, while the left ordinate gives the content of mono and di- and polychlorine products in weight% and on the right ordinate the ratio between mono-chlorine and dichlorine product is indicated.

It is clear from the diagram that with an increasing chlorine content in addition to the monochloro compounds (graphs I), the amount of the dichloro compounds, ie of the products containing the two methyl chloride groups, increases significantly (graphs II). As the chlorine content increases, the ratio of monochloro compounds to dichloro compounds decreases (Graphs III).

The value of this ratio is lower at higher temperatures.

In the first reaction step of the preparation, it is possible to set the appropriate ratio between monochloro-30 and dichloro compounds by an appropriate choice of temperature, of the xylene-hydrochloric-formaldehyde molar ratio and of the chlorine content.

In the polysulfide-forming step, as a result of the bonding via the S groups, dimers, trimers and optionally

a

35 tetramer forms, making the product a mixture. This process is illustrated by the reaction schemes C), D) and E).

The reaction according to reaction scheme E) only proceeds to an appreciable extent in the case of a high content of 8601966 t * - 5 - dichloro compounds. However, in the preparation of additives, the amount of monochloro compounds is a multiple of the amount of dichloro compounds, and therefore the amount of tetramers and other oligomers formed in the polysulfide forming step is negligibly small. Also negligibly small is the amount of extremely complicated compounds formed from tri- and polychlorinated compounds.

In Fig. 2, the ratio of monochloro-10 compounds to dichloro compounds is plotted on the basis, while the ordinate shows the respective content of dimer or trimer in parts by weight.

The values indicated for the starting material xylene were calculated.

It can be seen from the Fig. That as the ratio of monochloro compounds: dichloro compounds decreases, the amount of dimers decreases sharply (I), while the amount of trimers increases sharply (II). At a monochloro derivative: dichloro derivative ratio of 20: 1, the product still contains approximately 12% trimers, while at a ratio of 4: 1 50% trimers are already present.

With regard to the preparation of EP additives, the ratio of dimers to trimers in the composition of the organic polysulfides is of decisive significance. The dimers are more soluble in non-polar solvents, lubricating oils since their hydrocarbon content is higher, therefore, with an increasing dimer content of the polysulfides, the solubility of the product increases and. compatibility with other additives improves. The polysulfides with a high trimer (optionally tetramer) content are therefore not suitable for the preparation of EP additive compositions. This problem primarily arises when the thiophosphonates prepared from high molecular polyisobutylene are mixed with succinimides; such blends are important components of the EP additive compositions.

According to the invention, it has now been recognized that for the preparation of organic polysulfides, which are also suitable for the preparation of EP additives, it is an unavoidable requirement to use in the chloromethylated intermediates set the ratio between mono chlorinated and dichlorinated compound to at least 7: 1. When an isomer mixture of xylene is used, this condition is fulfilled if chlorine is methylated at a temperature of 35 ° C until a chlorine content of 14% is obtained. A lower chlorine content is not economical because of the large amount of unreacted xylene remaining in this case. At too low temperatures, the reaction time increases sharply.

A favorable composition can also be achieved by chlorinylation at higher temperatures, but thereby reducing the molar content of paraformaldehyde. For example, when xylene is chlorinated at 12 DEG-14% chlorine at 80 ° C to a chlorine content of 15, wherein the molar ratio between hydrochloric acid, paraformaldehyde and xylene is 4: 0.6: 1, a product is also formed which contains at least seven times as much mono-chlorinated compound as dichlorinated. Due to the higher temperature, the reaction time decreases substantially. Suitable EP additives for lubricating and hydraulic oils, greases and liquids for metalworking as well as for mixing with highly polar additives are organic polysulfides, which are prepared from a chloromethylated intermediate containing at least three times as much mono chlorinated product as dichlorinated . If an isomer mixture of xylene is used as starting material, this condition is fulfilled with certainty if methylation is carried out at a chlorine content of at least 50 ° C to a chlorine content of 17.5%.

When the content of monochloro compounds in the chloromethylated intermediate is not at least three times the content of dichloro compounds, the solubility of the polysulfide prepared therefrom is not satisfactory, the product is ambiguous and it is divided into several phases. At such a low mono-di ratio, oligomers and polymers with a higher molar mass are already formed.

The chloromethylation can be accelerated substantially by adding hydrogen chloride gas and the amount of 8661966 - 7 -

Q

The quantity of dilute hydrochloric acid remaining after the reaction is smaller, but the proportion of dichlorinated compounds in the product is substantially higher with the same chlorine content. A similar effect is also found in the use of Lewis acids as a catalyst.

The process according to the invention also extends to the re-use of the dilute hydrochloric acid, which remains after the chloromethylation. Namely, the amount thereof is considerable due to the quadruple molar excess. Since its HCl content is still relatively significant (generally 24-28%), it is possible to use it again. This recycle of the waste acid is preferably carried out such that the HCl content of the hydrochloric acid obtained in the last reaction is less than 15%. When the reaction time increases sharply, it can be compensated by a higher temperature or by using a Lewis acid as a catalyst, but consideration must always be given to maintaining the desired mono-di ratio.

The physicochemical properties of the EP additives prepared by the process according to the invention depend strongly on the composition and structure of the hydrocarbons used as starting compounds. First, the number of hydrocarbon atoms and the structure of the alkyl group bonded in the aromatic ring are significant because they determine the reactivity of the alkyl aromatic hydrocarbon group and also affect the properties and EP activity of the organic product.

The main property of the EP additives according to the invention is, in addition to other important properties, such as their suitable solubility and other applicability related physicochemical properties (viscosity, flash point, heat stability, foaming), the EP action, which was tested according to standardized regulations. These regulations can be read, for example, in DIN 51350, ASTM D 2266-67, ASTM D 2783-69 T standards.

The studies performed with the polysulfides show 8601 966% - 8 -

G

that the favorable EP action can be traced not only to the amount of sulfur introduced into the lubricant, but also to the organic groups bound to the sulfur.

The EP activity of the aromatic hydrocarbon groups keeps the polysulfides generally better, but their solubility is poorer. The latter property can be improved in chloromethylation by increasing the monochloro-dichloro ratio as well as by increasing the number and molar mass of the alkyl substituents bound to the aromatic ring.

When conducting the tests for the EP action, it was also found that the effectiveness depends decisively on the preparation technology of the organic polysulfide. The pure and more homogeneous product which can be prepared according to the invention is more effective than, for example, a product obtained by directly sulfurizing isobutylene, as could be determined by the method using the four-ball device and the FZG device.

The invention is explained in more detail below with reference to examples.

EXAMPLE I

A heatable and coolable round bottom flask with grinding stopper equipped with a stirrer and thermometer was charged with 483.5 g of 35% hydrochloric acid and 41.7 g of powdered paraformaldehyde. The mixture was heated to 50 ° C and stirred until dissolved (approx. 1 hour). The mixture was then cooled to 35 ° C and mixed with 123 g of xylene isomer mixture, which corresponds to a HCl-xylene-30 molar ratio of 4: 1. The mixture was stirred vigorously and chloromethylated until a chlorine content of 14% (approx. 20-25 hours) was reached. The stirrer was then turned off, the mixture cooled to room temperature, transferred to a separatory funnel, the chloromethylated xylene constituting the upper phase separated and freed from residual hydrochloric acid by blowing nitrogen. The composition was determined by gas chromatography.

8601966 * - 9 -

Unreacted xylene 38.9% monochloro derivatives 57.6% dichloro derivatives 3.1% mono di ratio 18.6 The chloromethylated xylene freed from the hydrochloric acid was reacted with a sodium polysulfide of Na2S2 composition. After distilling off the unreacted xylene, the sulfur content of the product was 28.2%. The organic polysulfide has unlimited solubility in xylene, gas oil, pure petrol and lubricating oils.

a) The organic polysulfide prepared according to Example 1 was stirred in a ratio of 1: 1 with a mixture consisting of an oxidation stabilizer, dispersant and anti-corrosion agents. The EP additive obtained in this way is clear and transparent at room temperature, the opalization point being at -3 ° C. The EP additive was added in an amount of 6.5% to a base oil of viscosity grade SAE-80 W-90. The welding force of the oil provided with this additive 20 measured according to DIN 51350 is 6000 N. In the FZG test (type: A / 16, 6/90/10) of the same oil carried out according to DIN 51354, the degree of damage was> 12 . The specific mass change: 0.032 mg / MJ.

b) The following study was carried out for comparison.

In the manner described in example I it was.

xylene isomer mixture is chloromethylated, but at a temperature of 50 ° C and up to a chlorine content of 17.5%.

The chloromethylated xylene (determined by gas chromatography) had the following composition: 30 unreacted xylene 29.0% monochloro derivatives 60.0% dichloro derivatives 12.0% mono di ratio 5.0.

This chloromethylated xylene was reacted for the preparation of the organic polysulfide with sodium sulfide of the composition Na 2 S 4. An EP additive was prepared from the 38.3% sulfur-containing product as described in Example I. This is cloudy at room temperature and falls after 8601966

V

- 10 - having stood for one day, divided into two stages. Opalization point: 38 ° C. The product has unlimited solubility in xylene and gas oil, in pure petrol and in oils with a low aromatics content.

C) The organic polysulphide prepared according to Example Ib was added in an amount of 3% to a lubricating grease. As a result, its welding force increased from 2000 N to 5000 N.

d) The organic poly-10 sulfide prepared according to Example 1b was added in an amount of 3% to a cooling and lubricating liquid which can be used in the metalworking. As a result, the welding force increased from 1600 N to 5000 N.

EXAMPLE II

The procedure is as described in Example 1, but the starting material is not the xylene isomer mixture, but pure m-xylene. After a chloromethylation for 15 hours to a chlorine content of 14%, the following composition was determined by gas chromatography: 20 unconverted m-xylene 36.2% monochloro derivatives 61.0% dichloro derivatives 2.7% mono-di ratio 22.6.

Air was blown through the chloromethylated xylene to remove the hydrochloric acid residues. After reaction with sodium polysulfide of Na2S2 composition, the product had a sulfur content of 36.3%. It has unlimited solubility in xylene, gas oil, pure petrol and in lubricating oils.

The sulfur-containing product was added in an amount of 6.5% to a base oil with viscosity classification SAE-80 W-90. As a result, the welding force, determined with the four-ball device, increased to 6500 N (test according to DIN 51350).

EXAMPLE III

The procedure is as described in Example 1, with the proviso that the xylene isomer mixture 8601966-11. * at 80 ° C to a chlorine content of 20% chloromethylates. The following composition was determined by gas chromatography: unreacted xylene 22.3% 5-chloro derivatives 45.9% dichloro derivatives 27.0% other 4.8% mono-di ratio 1.7.

Chloromethylated xylene freed from hydrochloric acid residues by air purging was reacted with sodium sulfide of Na2S2 composition. After a short time, the product formed thereby can be divided into two phases. The upper phase constitutes 59% of the product, has a sulfur content of 42.1% and has unlimited solubility in xylene and gas oil, 15 in pure petrol and in lubricating oils. The bottom phase forms 41% of the product and contains 57% sulfur.

It is soluble in benzene and xylene in an amount of 10 g / 100 g of solvent, practically insoluble in pure petrol and in lubricating oils. This method is not suitable for the economic preparation of EP additives.

EXAMPLE IV

Chloromethylation is carried out in the manner described in Example I, but 220 g of octylbenzene is used as the starting material and chloromethylation is carried out to a chlorine content of 9.1% (approx. 40 hours). The following composition was determined by gas chromatography: unreacted octylbenzene 42.8% monochloro derivatives 54.5% dichloro derivatives 2.7% mono-di ratio 20.2.

Nitrogen was blown through the chloromethylated octylbenzene to remove hydrochloric acid residues. The reaction with sodium polysulfide of Na2S2 composition gave a product with a sulfur content of 24.8% which is soluble in xylene, gas oil, pure gasoline and lubricating oils.

The sulfur-containing product was added in an amount of 6.5% to a base oil with viscosity classification SAE-80 8601966

Si - 12 - W-90 added, of which the welding force, determined with the four-ball device, increased to 6000 (test according to DIN 51350).

EXAMPLE V

The procedure is as described in Example 1, with the proviso that 285.3 g of dodecylbenzene is used as the starting material and that it is methylated to a chlorine content of 7.5% (approx. 70 hours). The following composition was determined by gas chromatography: 10 unreacted dodecylbenzene 44.0% monochloro derivatives 53.5% dichloro derivatives 2.5% mono di ratio 21.4.

Nitrogen was passed through the chloromethylated dodecylbenzene to remove hydrochloric acid residues. After reaction with sodium polysulfide, a product with a sulfur content of 20.6% is formed. The product was added in an amount of 6.5% to a base oil with viscosity classification SAE-80 W-90, whereby the welding force, determined with the four-ball device, increased to 5500 N (test according to DIN 51350).

EXAMPLE VI

Chloromethylation is carried out in the manner described in Example 1, but using the hydrochloric acid which remains after the chloromethylation described in Example 1. This hydrochloric acid contains 24% HCl. Chloromethylation is carried out at 50 ° C to a chlorine content of 14.2% (approx. 40 hours). The following composition was determined by gas chromatography: unconverted xylene 39.6%, mono-chloro derivatives 55.1%, dichloro derivatives, 4.5% mono-di ratio 12.2.

The chloromethylated xylene was freed from hydrochloric acid traces by passing nitrogen and then reacted with sodium sulfide of composition.

8601966 * - 13 -

The product obtained had a sulfur content of 29.6%. The product was added in an amount of 6.5% to a base oil with viscosity classification SAE-80 W-90, the welding force of which, determined with the four-ball device, therefore increased to 6000 N (test according to DIN 51350).

EXAMPLE VII

The procedure is as described in Example 1, except that 241.8 g of hydrochloric acid are used.

This corresponds to an HCl-xylene ratio of 2: 1 (not 10 4: 1, as before). Chloromethylation is carried out at 40 ° C to a chlorine content of 14% (approx. 40 hours). The following composition was determined by gas chromatography: unreacted xylene 40.1% monochloro derivatives 56.6% dichloro derivatives 4.0% mono-di ratio 14.2.

Nitrogen was passed through the chloromethylated xylene to remove hydrochloric acid traces. Then the reaction was carried out with sodium sulfide of Na2S3 composition. The product had a sulfur content of 28.4%. This product was added in an amount of 6.5% to a base oil with viscosity classification SAE-80 W-90, which increased the welding force determined by the four-ball device to 6000 N (test according to DIN 51350).

EXAMPLE VIII

A round bottom flask equipped according to example I, which additionally had a gas supply and gas discharge, was charged with 1800 g 28% hydrochloric acid and 339 g paraformaldehyde. The mixture was heated to 50 ° C and stirred until the total paraformaldehyde had dissolved (about 1 hour). The mixture was then cooled to 25 ° C and mixed with 1000 g of xylene isomer mixture. Hydrogen chloride gas was then introduced into the mixture. The chloromethylation was continued to a chlorine content of 14.1% (approx. 18 hours). The following composition was determined by gas chromatography: 8601966 * - 14 - unreacted xylene 45% monochloro derivatives 45% dichloro derivatives 10% mono-di ratio 4.5.

The chloromethylated xylene liberated from hydrochloric acid by passage of nitrogen was reacted with sodium polysulfide of composition. The resulting product had a sulfur content of 41.5%, and is unlimited soluble in benzene, xylene and gas oil, in pure gasoline and in lubricating oils to less than 10 g / 100 g of solvent.

a) The sulfur-containing product was added in an amount of 3% to a grease, the welding force of which increased from 2000 N to 5000 N.

b) The product was added in an amount of 3% to a metalworking coolant and lubricant, the welding power of which increased from 1600 N to 5000 N.

EXAMPLE IX

For comparison, according to German patent specification 2 838 981, a high pressure vessel equipped with a stirrer, heating jacket and cooling hose was filled with 526 g of powdered sulfur, 920 g of cooled liquid isobutylene and 269 g of also cooled liquid hydrogen sulphide. After closing the reactor, the mixture was heated to 170 ° C. The pressure thereby rose to 92 bar. The reaction mixture was stirred for 10 hours, the pressure slowly falling below 20 bar. The reactor was then cooled to room temperature and its contents, a dark reddish brown liquid, were poured into a distillation flask. After distilling off the 30 unconverted components, clarifying and purifying, 760 g of product with a sulfur content of 42.5% were obtained.

The sulfur-containing product was added in an amount of 6.5% to a lubricating oil of viscosity grade SAE-80 W-90, the welding power of which increased to 35 3800 N.

The 6.5% of the gear oil additive was subjected to the 8601966 - 15 - * FZG test (type: A / 16, 6/9/10) according to DIN 51354 regulations. The degree of damage was 12, the specific mass change 0.122 mg / MJ.

EXAMPLE X

The procedure is as described in Example 1 with the proviso that only 21 g of paraformaldehyde are used. The mixture was heated to 80 ° C and stirred for 12 hours after addition of the xylene. The analysis was as follows: chlorine content 13% 10 unconverted xylene 42.7% monochloro derivatives 52.8% dichloro derivatives 3.5% mono di ratio 15.1.

Air was passed through the chloromethylated xylene to remove hydrochloric acid residues. Then the reaction was carried out with sodium polysulfide of composition Na2S2. The product obtained had a sulfur content of 37.2% and was freely soluble in xylene, gas oil, pure gasoline and lubricating oils.

The product was added in an amount of 6.5% to a base oil with viscosity classification SAE-80 W-90, as a result of which the welding force, determined with the four-ball device, increased to 6000 N (test according to DIN 51350).

8601960

Claims (6)

A process for the preparation of an EP additive suitable for the preparation of lubricating and hydraulic oils, lubricating greases and lubricating and cooling fluids which can be used in metalworking, with the general formula 5 (Rl'V- * rb) c (Sx) d wherein R1, R11 ... RV independently represent hydrogen, straight or branched or cyclic, saturated or unsaturated hydrocarbon groups having 1-40 carbon atoms or derivatives thereof, and the groups Ar independently represent aromatic hydrocarbon groups having a or represent several rings or derivatives of such groups, b is a number 1-5, c is a number 2-10, d is a number 1-9, and x is a number 1-6, 20 by conversion of organic chlorine compounds of the general formula (RI-V-Ar,) -Cl ba in which a is a number 1-5, with metal sulfides of the general formula MS nx in which M stands for alkali metal and / or alkaline earth metal, n 1 or 2 and 30. is a number 1-6, characterized in that ko hydrocarbons of the X "V general formula R-Arr with a formaldehyde solution and / or 8601966 s-η paraformaldehyde and aqueous hydrochloric acid and / or hydrogen chloride gas, optionally in the presence of a catalyst, chloromethylates and - for the preparation of EP additive mixtures, set the ratio 5 of monochloro compounds to dichloro and polychloro compounds to at least 7: 1, - for the preparation of EP additives for lubricating and hydraulic oils, greases and additives for metalworking, the ratio between monochloro compounds and di - adjust 10 chlorine and polychlorine compounds to at least 3: 1, then convert the chloromethylated product with the metal sulphide of formula MnSx and purify the final product, if necessary. 2. Process according to claim 1, characterized in that for the preparation of sulfur compounds suitable as EP additives for lubricating oils, a xylene isomer mixture is used at a maximum of 40 ° C while maintaining a molar ratio between hydrochloric acid, paraformaldehyde and xylene of At least 4: 1.2: 1 until the chlorine content of 12-14% is chloromethylated, after which the chloromethylated xylene is reacted with sodium polysulfide and the product is purified, if necessary. 3. Process according to claim 1, characterized in that a xylene isomer mixture is maintained at 40-50 ° C while maintaining a molar ratio for the preparation of EP additives for lubricating and hydraulic oils, lubricating greases and auxiliaries for metalworking. of hydrochloric acid, paraformaldehyde and xylene of at least 4: 1.2: 1 to a chlorine content of 14-17.5% chloromethylation, after which the chloromethylated xylene is reacted with sodium polysulfide and the product is purified, if necessary. 4. Process according to any one of claims 1-3, characterized in that the hydrochloric acid remaining after the chloromethylation is reused at a lower concentration. 5. Process according to claim 1, characterized in that for the preparation of sulfur compounds suitable for the EP additive mixtures of lubricating oils 8601966 Jfi - 18 - »a xylene isomer mixture at a maximum of 100 ° C while maintaining an HCl paraformaldehyde -xylene molar ratio of up to 4: 0.8: 1 until a chlorine content of 10-14% is chloromethylated, then the chloromethylated xylene is reacted with sodium polysulfide and the product is purified, if necessary. 6. Process according to claim 1, characterized in that for the preparation of EP additives for lubricating and hydraulic oils, lubricating greases and auxiliary agents for metal processing, a xylene isomer mixture is maintained at 80-100 ° C while maintaining a HCl paraformaldehyde-xylene molar ratio of at most 4: 1: 1 to a chlorine content of 12-17.5% chloromethylate, after which the chloromethylated xylene is reacted with sodium polysulfide and the product is optionally purified. 6601966