HU197936A - Process for producing ashless detergent-dispergent additive of alkenyl-succinimide type - Google Patents

Abstract

In the preparation of the alkenyl succinimide additive of the present invention, maleic anhydride with polyolefin at a pressure of from 60 to 1500 kPa, preferably from 60 to 600 kPa, maleic anhydride, the molar ratio of unmodified polyolefin of maleic anhydride present in the reaction mixture to the addition is up to 20 mole, preferably 6 mole. - 0.001 to 2.0% by weight, based on the total weight of maleic anhydride and polyolefin, in the presence of poly (alkylphenol) or known amine-type oxidation inhibitors and / or halogenated paraffins, decomposing at the reaction temperature and / or reacting the reaction; polyolefin using Mn poly (iofefin-410 + (- ^) ^ (- ^ 2) 1 ^ -related average molecular weight polyolefin, which may have a molecular weight different from the calculated ± 35O, in the context of which n is the polyethylene used in the acylation reaction in a molecule of polyamine and N is the numerical average molecular weight of the base ψζ or other hydrocarbon mixture in which the additive is used. t -1-

Description

The present invention provides an ashless detergent of the alkenylsuccinimide type. a dispersant additive which is advantageously used to improve the properties of lubricating oil compositions.

Ash-free alkenylsuccinimide type _s additives are widely used to improve the detergent-dispersant (DD) properties of modern motor oils. Through their anti-soaking, acid neutralizing, dispersion stabilizing, anti-sedimenting action, they prevent oil-insoluble soiling from contaminants (dust, soot, etc.) and engine-generated sludge, varnish and carbon black materials, etc. from outside the engine oil. They can increase the shelf life of lubricating oils and make engines safer.

Alkenylsuccinimides are used in compositions, in particular, with other known sulfonate, phenate, salicylate, etc., containing metallic DD additives. In their preparation, alkenyl succinic anhydrides are first synthesized by the addition of olefinic polymers and maleic anhydride to form amides, imides and mixtures thereof with amines or amine-containing compounds. Such processes are described in U.S. Patent Nos. 3,018,291, 3,024,237, and 3,405,065.

Alpha-olefins such as ethylene, propylene, 1-butene, isobutene, 1-hexene, or substituted alpha-olefins such as styrene, p-methylstyrene, or diolefins such as butadiene, isoprene may be used to form the oil-soluble alkenyl group. , homopolymers and copolymers thereof.

For succinimide type additives, polyalkylene polyamines such as ethylenediamine, diethylenetriamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, propylene diamine, 1,4-bis (often used to form basic surfactant groups) are often used. aminoethyl) piperazine or alkyl and / or arylamines such as diethylamine, n-butylamine * isopropylamine, aniline, benzylamine or amino alcohols such as ethanolamine, diethanol as well as triethanolamine. Compounds of this type are disclosed in U.S. Patent Nos. 3,287,271 and 3,172,892.

By altering the structure of the polar group, other advantageous succinimides have also been synthesized. The basic group of succinimides has been modified such that sulfur, hydroxyl, keto, carboxyl, skin or chlorine groups are usually attached to the covalent nitrogen atoms. In addition to DD, these products have antioxidant, anti-corrosion, anti-wear and anti-friction properties. Their preparation processes are described, inter alia, in U.S. Patent Nos. 3,574,101 and 3,755,433, European Patent Nos. 61,329 and 1,667,975, and German Patent Nos. 3,406,257. Although this type of structure modification may be advantageous due to the appearance of side effects, it results in lower DD efficiency products due to the reduction of the basic nitrogen content and hence the acid neutralization and adsorption capacity of the new molecular structure.

Another frequently followed way to increase DD activity is to increase the active ingredient content of the additive. This is achieved by the fact that the conversion of the thermally initiated addition reaction of polyolefins and malic anhydride is only 50-70%. Conversion can be increased by increasing the temperature and the molar ratio of maleic anhydride to olefin, but such conditions already favor the formation of coke-tar-by-products. The removal of such oil-insoluble or partially oil-soluble by-products is only possible at a significant cost increase. Therefore, another possible way to increase the conversion is to use alkenyl succinic anhydride using the chlorine catalyst. During this addition, chlorine gas is bubbled through the reaction mixture, which, according to a mechanism not yet known ⁷ , inhibits side reactions leading to gelling and tar formation and catalyzes the addition reaction. Such processes are described in German Patent Nos. 219,792 and French Patent Nos. 2,312,510, with the disadvantage that the chlorine added to the additive by double bonding under the conditions of use of the additive molecule causes on metal surfaces, on the other hand, when added to the basic part of the additive, it binds part of the acid neutralizing capacity.

As a result of today's engine design improvements, engines of smaller size and higher specific power are being manufactured, which, at higher temperatures and pressures, are more demanding than ever for lubricating oils. Therefore, the requirements can only be met by overdosing conventional additives. At the same time, new types of lubricating oils have increased demand for high-base and nitrogen-containing succinimide types with higher active ingredient and higher OD efficiency.

The aim is to develop a technology for polyalkylene-polyamine-based mono- and poly-alkylene-polyamine based high performance detergent dispersants in high performance engines without additive

-2197936 an additive having the structure of bis-succinimide can be prepared.

Studying the relationship between technological parameters, additive composition and efficacy, we came to the realization that such a system of technological parameters is possible. the use of a co-additive and / or additives, whereby the addition of polyolefin and maleic anhydride takes place at a higher degree of conversion than the conventional thermally initiated reaction and at the same time suppresses the adverse side reactions.

It has further been found that the properties of the doped motor oil are better when there is a proper relationship between the average molecular weight of the polyolefin used in the addition reaction and the average molecular weight of the base oil into which the oil additive is prepared.

It has now been found that by satisfying the following conditions, a product may be obtained which is more effective than known in the art, and which eliminates the disadvantages of known additives due to over-distribution.

Addition of the intermediate alkenyl succinic anhydride (MSA) to the polyolefin during the manufacture of the additive by the addition of maleic anhydride (MSA) in one or more steps at a temperature of from 160 to 260 ° C, preferably from 180 to 100 ° C. At a pressure of 600 kPa, the maleic anhydride / olefin molar ratio is 0.6 to 2.0, preferably. The reaction is carried out at a reaction time of from about 0.9 to about 1.5 hours, preferably from about 0.001 to about 8.0% by weight, over a reaction time of from 1 to 24 hours, preferably from 4 to 16 hours, and / or catalyzing the addition. The formation of harmful by-products can be suppressed under the additional condition that the addition of MSA is carried out such that the molar ratio of MSA to unreacted polyolefin in the reaction is not more than 20 moles, preferably 6 moles per mole.

The reaction mixture is cooled to 80-160 ° C, optionally mixed with 0-65% by weight of a lubricating oil refiner, having a kinematic viscosity of 10-50 mm ² / see at 40 ° C and a flash point above 130 ° C, and 0.2-10 hours. % filtration aids such as perlite or bentonite are clarified and filtered.

It has now been found that compounds which decompose at the reaction temperature and / or catalyze the maleic anhydride-polyolefin coupling reaction have an inhibitory effect on the formation of side reactions, i.e. the formation of tar-like substances. For example

Compounds containing from 8 to 65% by weight of halogens, such as chloro-paraffins, or polyacetylphenols or other known commercially available b. additive inhibitors.

The olefinic starting materials used are homo- and / or copolymers of ethylene, propylene, butylene or other olefins having an alpha-double bond in the range of M átlagos = 200-30000, preferably M _ft = 500-3500.

It has been found that it is also possible to increase the efficiency of DD by adjusting the ratio of the polar apolar moiety of the alkenylsuccinimide additive to the properties of the parent oil in which the additive is to be used.

Alkenyl succinic anhydride and polyalkylene polyamines have different molar ratios, so-called. The acylation reaction produces mono-, bis-, and multiple-bonded polysuccimides. Their solubility, nitrogen content, base number and efficiency of DD depend on the average molecular weight and molar ratio of the acid anhydride and polyalkylene polyamine starting materials used. It has been shown that, depending on the numerical average molecular weight of the base oil used later and the average number of basic nitrogen atoms in the polyethylene polyamine used, the structural variations of the additives which are particularly favorable for the DD effect have a preferred range of numerical average molecular weight:

potioleftn-10 + '(- ^ -) ³ + F where: pc / io / ef ,,: numerical average molecular weight of the polyolefin to be used in the synthesis of the succinimide additive, which may be ± 350 units of molecular weight. M _'o of the base oil or other hydrocarbon mixture of number average molecular weight, wherein the additive is to be applied. n is the number of basic nitrogen atoms in the average molecule of polyalkylene polyamine used in the synthesis of the succinimide additive.

The side chain range thus determined can be advantageously used when the synthesized additives have a base to nitrogen (TBN / N) ratio of 5 to 35.

The alkenylsuccinimide type additive as described above is prepared in one or more steps, wherein the alkali ml succinic anhydride (AKBKA) and the polyethylene polyamine (PEPA) are in the range of 80-230 ° C, preferably 140-200 ° C, The AKBKA / PEPA molar ratio of 0.6-3.0, preferably 0.8-2.2, optionally in a solution of hydrocarbon and / or other petroleum products, is reacted with continuous boiling of the reaction water. During this acylation, any unreacted amines are removed, if necessary, by vacuum and / or nitrogen bubbling. If necessary, the reaction product may be prepared with 3 or with oil or other hydrocarbons

The solution of -3197936 is filtered with or without filter aids to remove any mechanical impurities, with or without prior clarification.

The following examples illustrate the process of the present invention. In Examples A, B and E, alkenyl succinic anhydride was prepared according to the invention, and in Examples C and D, a different procedure was used.

1-6. Examples 9 and 9 for the preparation of the additive according to the invention according to Examples 7-8. and in counter-examples a different procedure was used.

"A" Example

950 g (1.00 mole) of polyisobutylene, having a numerical average molecular weight of 950 g and 113.4 g (1.15 mole) of maleic anhydride, was evacuated, pressure-resistant, and autoclaved with a stirrer and inserted into the reaction mixture for measuring temperature. 35% by weight of a commercially available oxidation inhibitor of 2,6-ditert-butyl-p-cresol. The autoclave creates an inert atmosphere by introducing nitrogen gas. The reaction mixture was heated to 226 ° C with stirring for 100 minutes and maintained at 220-230 ° C with vigorous stirring for 8 hours. During this time, the pressure in the autoclave is 60-600 kPa. The molar ratio of maleic anhydride to unconverted polyisobutylene is less than 1.5 mol / mol throughout the operation. The product mixture, while still being stirred, was cooled to -205 ± 5 ° C and at this temperature and 25 kPa absolute pressure, the unreacted maleic anhydride was removed. The TPN (Total PIBBA Number) of the product mixture filtered after clarification is 77 mg KOH / g (theoretical: 107), water soluble acid content:

1.1 mg KOH / g.

Example "B"

In the autoclave of Example A, 1260 g (1.20 moles) of polyisobutylene having a numerical average molecular weight of 1050 and 147.9 g (1.50 moles) of maleic anhydride and 0.45% by weight (based on the starting materials) The diphenylamine antioxidant additive was weighed in. In an autoclave, an inert atmosphere was introduced by introducing nylogen gas and an absolute pressure of less than 100 kPa was maintained under constant stirring at 220-228 ° C for 8 hours. and the molar ratio of unconverted PTB to not more than 2 moles / mole The product mixture was cooled to 205 ± 5 ° C while still stirring, then at this pressure and at an absolute pressure of less than 50 kPa, under nitrogen the unreacted maleic anhydride is removed to give a mixture of the product obtained with a suitable hydrocarbon diluent having the following characteristics:

VK400 (kinetic viscosity): 23 mm ² / sec; VI (viscosity index, 76 flash point: 196 ° C) is mixed so that the product has an oil content of 30% by weight. After filtration with or without excipients, the product has a TPN of 48 mg KOfl / g (theoretical: 68, 4) water soluble acid content: 0.6 mg KOH / g.

Example "C"

A mixture of polyisobutenyl succinic anhydride is prepared as in Example A but without the use of an antioxidant additive. The product had a TPN of 46.3 mg KOH / g (theory: 107) and a water-soluble acid content of 8.7 mg KOH / g. The product thus obtained can be filtered under the same filtration conditions three times as long as the product obtained in Example A.

Example "D"

The autoclave of Example A contained 600 g (1.00 moles) of polyisobutylene having a number average molecular weight of 600 and 392.4 g (4.0 moles) of maleic anhydride and 0.45% w / w of the starting materials. An anti-oxidant additive of the ditert-butyl-p-cresol type is added. The addition reaction was carried out in the same manner as in Example A, except that the ratio of maleic anhydride to polyisobutylene was max. 25 mol / mol. After the addition reaction, the excess maleic anhydride is removed as described in Example A. After clarification, the product mixture was filtered with a TPN of 146.6 mg KOH / g (theoretical TPN = 162.9 mg KOH / g) and a water-soluble acid content of 18.2 mg KOH / g. Further processing of the very poorly filterable intermediate with limited oil solubility is neglected.

Example "E"

In the autoclave of Example A, 1300 g (1.00 moles) of polypropylene amines had a numerical average molecular weight of 1300 g and 122.5 g of maleic anhydride and 0.45% by weight of the starting material, an antioxidant and dioctyldiphenylamine. 8% by weight of chloro-paraffin (40% by weight of chlorine) catalyst is added. By introducing a constant nitrogen gas in the autoclave, an inert atmosphere and an absolute pressure of less than 100 kPa are created.

The mixture was stirred at 220-228 ° C for 8 hours with constant stirring. The spatial mékelegyet ^c - 205 ° C ± 5 ° C and at this temperature, and less than 50 kPa in absolute pressure, nitrogen inlet through the reaction mixture, the unreacted maleic hydride removed - additional stirring '. The product mixture thus obtained contains a diluent having the following characteristics: kinematic viscosity: 23 mm ² / sec at 40 ° C;

-4197936 viscosity index: 76; Flash point: 196 [deg.] C. - Mixed to give an oil content of 30% by weight. After filtration with or without auxiliaries, the product mixture has a TPN of 50.5 mg KOH / g and a water-soluble acid content of 0.8 mg KOH / g.

Example 1

To 510 g of the polyisobutenyl succinic anhydride prepared in Example ^{1 in} an inert atmosphere autoclave is added 65 g of tetraethylene pentamine under stirring at <100 ° C for 5 minutes. The reaction mixture was maintained at or near atmospheric pressure for 3 hours at 17 ° C and then at an absolute pressure of less than 50 kPa for 2 hours at 205 ° C. The N-content of the additive thus obtained is 4.2% by weight, TBN / N ratio; 30. The additive thus obtained was stirred at an amount of 3% by weight for further use M _'p = number average molecular weight 400, U marked base oil.

Example 2. ⁰

In an inert atmosphere an autoclave were charged 600 g _W "obtained in Example borosiyánkő polyisobutenylsuccinic anhydride. 39.1 g of triethylene tetramine are added to the material heated to 100 [deg.] C. with stirring for 15 minutes. This reaction mixture was heated at 125 ° C and 145 ° C for 2 hours, then at 185 ° C for 3 hours at 185 ° C and then for 2 hours at an absolute pressure of 195 ± 5 ° C. we. The additive has an N content of 2.3% by weight and a TBN / N ratio of 18. The additive thus prepared is further mixed with 3% by weight of base oil, denoted by Wn, of a number average molecular weight of _Wn = 500.

*

Example 3

1300 g of the polyisobutenyl succinic anhydride prepared in Example B is charged to an inert atmosphere autoclave which is heated to 120 ° C with stirring. To this is added diethylenetriamine (28.7 g) over 15 minutes with stirring and the reaction mixture is kept at 180 [deg.] C. for 2 hours at absolute pressure above 60 kPa and then for 2 hours. Additive N content: 0.88 wt%, TBN / N ratio of 10. The additive thus obtained was stirred at an amount of 3% by weight for further use 5vt _no == 51Q number average molecular weight of W marked base oil.

Example 4

1210 g of the polyisobutenyl succinic anhydride prepared according to Example B are weighed into an inert atmosphere autoclave. This was heated to -70 ° C with stirring and 69.9 g of a polyethylene-polyamine mixture having a number average molecular weight of 150 were added over 5 minutes. and the. number of basic nitrogen8 atoms: 4.1. The reaction mixture was then maintained under stirring at 175 ° C for 3 hours at absolute pressure above 80 kPa and then below 205 ° C for 1 hour. The additive has an N content of 2.1% by weight and a TBN / N ratio of 26. The additive thus obtained is mixed with 3% by weight of base oil "X" for further use, M "" = 440.

Example 5

To the polyisobutenyl succinic anhydride prepared in Example B (885 g) in an inert autoclave was added 17.1 g of ethylenediamine under stirring at 55 ° C over 2 minutes. This reaction mixture was stirred for 4 hours at 165 ° C, absolute pressure above 90 kPa, and then held at 185 ± 5 ° C for a further 1.5 hours under reduced pressure. The additive thus obtained has an N content of 0.88% by weight and a TBN / N ratio of 21. The additive thus prepared is mixed with 3% by weight of base oil Y having a number average molecular weight of 700%.

Example 6

In an inert atmosphere an autoclave were charged 700 g of polyisobutenyl succinic anhydride, prepared transfer reaction as in Example "B" and maleic anhydride 30/70 chromatographically molekulafömegű an average and an average molecular weight _of 1 050 550 polyisobutylene. To do this, while stirring at 110 ° C for 5 minutes, 41 g of a polyethylene / polyamine mixture having a number average molecular weight of 150 and the number of basic nitrogen atoms were:

4.1 - We give. This reaction mixture was stirred first at an absolute pressure of greater than 70 kPa for 5.5 hours at 155 ± 5 ° C and then at an absolute pressure of less than 70 kPa,? for 180 hours at 180 ° C. The N-content of the additive thus obtained is:

2.2 wt%, TBN / N ratio of 18. The additive is thus obtained an additional use for the purpose _o = 510 number average molekulaJőmegű W jeíű aiapolajhoz. mix in 3 volumes.

Example 7

850 g of the polyisobutenyl succinic anhydride prepared in Example C are weighed into an inert atmosphere autoclave. This was heated to 95 ° C with stirring and 45.6 g of tetraethylene pentamine was added over 10 minutes. This reaction mixture was maintained at 185 ° C for 6 hours at absolute pressure above 50 kPa and then for 1 hour. The additive had an N content of 1.88 wt% TBN / N at 16.5. The additive thus obtained was stirred at an amount of 3% by weight for further use M _'o = 430 number average molecular weight of base oil X marked.

-5197936

Example 8

640 g of polyisobutenyl succinic anhydride prepared by the reaction of polyisobutylene (average molecular weight: 350) and maleic anhydride (Example A) are charged into an inoculated autoclave. To this was added 190 g of tetraethylene pentamine with stirring at 50 ° C for 2 minutes, then the reaction mixture was pressurized with absolute pressure greater than 50 kPa for 4 hours at 170 ° C and then for 2 hours at 205 ± 5 ° C. It is maintained at a temperature of C and an absolute pressure of less than 50 kPa. The additive thus obtained has an N content of 6.3% by weight, and a TBN / N ratio of 38. The additive thus prepared is mixed with 3% by weight of a base oil Z of numerically 600 for further use.

Example 9

1000 g of the polypropenyl succinic anhydride prepared in Example E are weighed into an inert autolane which is heated to 160 ° C with stirring. To this was added 42.6 g of tetraethylene pentamine (ΤΕΡΑ), with a number average molecular weight of 181, under stirring for 30 minutes. This reaction mixture was heated to 1775 ± 5 ° C for 4 hours, above 5 kPa and then for 1 hour. below absolute pressure. The additive obtained N content: 1.48%, TBN / N ratio of 15. The additive thus prepared for further use _Μ Λ "= ₁₅ molekulatömegíí average number of 43, marked X stirred 3 wt% base oil.

"A", "B", "C", "D", "E" and 1-9. The detergent-dispersant activity of the Examples 1 to 5 and the reference additives is given in Table 1.

First

Succinimide additives

Spreadsheet

DD Impact Assessment Data

base Oil sign Additive designation Dl,% (up to 100%) Deposition on disk mg U Pure base oil 0 215 V Pure base oil 2 220 X Pure base oil 1 245 Y Pure base oil 5 200 z Pure base oil 4 197 w Pure base oil 3 210 u Example 1 60 6 w Example 2 63 14 w 3. example 65 12 X Example A 72 8 Y Example 5 60 5 V Example 6 64 4 V Example 7 60 32 z Example 8 50 19 X Example 9 71 13 V K-l trading 61 14 X K-2 commercial 58 10

In the table, D1 is a detergent index

-6197936

"A", "B" and "E" as well as items 1-6. and

In the preparation of the additives of Examples 9, the average molecular weight polyisobutylenes, including polypropenyl, and the production parameter ranges were calculated using the equation used in the process of the invention. "C" and "D", and Figures 7-8. Examples 1 to 9 The processes for the preparation of the succinimides according to the invention differ in some respects from the most advantageous process according to the invention. Thus, the conditions for the preparation and purity requirements of alkenyl amber anhydride in Example C and the corresponding Example 7 are not met. In Example D, the molar ratio of maleic anhydride to polyisobutylene is greater than 20 mol / mol during the reaction. In Example 8, the average molecular weight of the polyisobutylene used is outside the calculated range.

1-9. The DD active ingredient of the polyisobutenyl succinimides prepared according to Examples 1 to 5 was evaluated by the following assay methods. A photometric assay was used to determine the dispersion stabilizing effect of the additives (detergent index). (Faust: Lubr. Eng. 10 (6), (1954) ⁶

Testing the antifouling effect with a plate coke oven R.N. Joli's in the VI. Stoneware World Congress (1959), "La12 Boratorium Selection Test for Detergent-Dispersive Additives to Lubricating Oils", c. was performed according to the method described in his presentation. The additive DD was assayed using additive concentrations of 3% by weight in base oils of similar character, with different numerical average molecular weights. The process of the present invention achieves a degree of conversion of 60 to 98%, based on the quality of the starting polyolefin, based on the conversion of polio10 to lefin, substantially free of harmful byproducts with an active ingredient content of 5 to 45% higher than the conventional thermal process. 5, preferably less than 2 mg KOH / g).

Based on the DD efficacy data of the succinimide additives, taking into account all 20 evaluation indicators, it can be concluded that the 1-6 compounds according to the invention are produced. and Examples 9 and 9, both as reference K-I and K-2, and as prepared by methods other than those described in Examples 7-8. Examples 1 to 4 are more effective than additives of the invention.

Table 2 summarizes the engine oil test results for the engine oil compositions and reference product of Examples 1 and 7, prepared with the commercial additive K-1.

Table 2

Bench Tests Petter W, 144

Features Viscosity Bearing ⁴ unloading inc. 40 ° C loss, FIDE rating % mg Example 1 2.0¾ Detergent 1 of 3.0¾ Example 1 additives FALL 77 48.7 71.3 1.5% Zn OTP Example 7 2.0¾ Detergent 1 of 3.0% Example 7; additives FALL 111 72.7 57.0 1,5'-M 201 Reference- 2.0¾ Detergent 1 additives 3.0¾ K-l SZI 99 42.0 69.0 0.5% M 201

Claims (2)

A process for preparing an ashless detergent dispersant additive of the alkenylsuccinimide type comprising adding maleic anhydride to the polyolefin in one or more steps in an inert atmosphere, in the presence of anhydrous 6-2.0, preferably 0.9-1.5 molar ratio, for a reaction time of 1-24 hours, preferably 4-16 hours, then the reaction mixture is cooled to 80-160 ° C, optionally 0-65 t petroleum compound, having a kinematic viscosity of 10-50 mm ² / s at 40 ^D C and a flash point above 10 ° C, and clarified and filtered using 0.2-10 l% of filtration aid to give the alkenyl succinic anhydride60- 230 ° C, preferably 140 ° C to 200 ° C, optionally in a solution of hydrocarbon and / or other petroleum products; under continuous boiling of this water, acylate the polyethylene polyamine with an average number of basic nitrogen atoms of 2 to 6 and a numerical average molecular weight of 60 to 210 with 1 Kenyl succinic acid / polyethylene polyamine 0.8- At a 2.2 molar ratio, the unreacted amine is removed, optionally by vacuum and / or bubbling in inert gas, and optionally using conventional purification procedures. maleic anhydride at a pressure of from 60 to 1500 kPa, preferably from 60 to 600 kPa; - in the presence of a known poly (alkylphenol) phenol or known amine-type antioxidant and / or halogenated paraffin based on the total weight of maleic anhydride and polyolefin, decomposed at a reaction temperature of 0.001 to 2.0% by weight, and / or 15 - reacting a polyolefin having an average molecular weight of ^{20 with a} molecular weight of ± 350, which is defined as a polyolefin, in which n is the number of basic nitrogen atoms per molecule of polyethylene polyamine used in the acylation reaction, and M _M is the numerical average molecular weight of the base oil or other hydrocarbon mixture in which the additive is used. Process according to claim 1, characterized in that the halogenated paraffin used as the antioxidant has a halogen content of from 8 to 65%.