NO167659B - GROUP-II METAL-OVERALCALIZED SULFURED ALKYL PHENOL WITH LOW VISCOSITY AND HIGH TOTAL BASIC NUMBER AND USE OF IT IN A LUBRICAN OIL MIXTURE OR A LUBRICAN OIL CONCENTRATE. - Google Patents

Description

The present invention relates to an oil-soluble, sulphurised alkylphenol which is strongly over-alkalised with metal of group II, and its use in lubricating oil mixtures and lubricating oil concentrates.

Group-II metal overalkalised sulfurized alkylphenols are useful lubricating oil additives that impart cleaning and dispersing properties to lubricating oil blends and provide an alkalinity reserve in the oil. An alkalinity reserve is necessary to neutralize acids formed during engine operation. Without this alkalinity reserve, the acids that are formed will result in harmful engine corrosion.

A method for the production of group-II metal-overalkalized sulfurized alkylphenols is described in US Patent No. 3,178,368, where an alkylphenol, a sulfonate, a high molecular weight alcohol, lubricating oil and sulfur are brought together and heated with stirring. Hydrated lime is then added, after which the system is heated and ethylene glycol is added. Water of reaction is removed, the mixture is cooled, and carbon dioxide is added. Unbound CC>2 is removed, and the reaction vessel is heated to remove ethylene glycol, water and the high molecular weight alcohol. The product is overalkalized by adding slaked lime and carbon dioxide.

Such previously known methods give group-II metal-over-alkalized sulfurized alkylphenols with a total base number TBN (TBN = Total Base Number) of approx. 250. Prior art Group II metal overalkalised sulfurized alkylphenols with a TBN greater than 275 are too viscous and require inefficiently large amounts of diluent to be handled in a practical manner, see US Patent No. 3,367,867. To overcome the problem of extremely high viscosities associated with Group II metal overalkalized sulfurized alkylphenols with high TBN, it is proposed according to US Patent No. 3,367,867 to use as alkyl groups in the alkylphenol mixtures of straight-chain and branched alkyl, whereby the products with suitable viscosity and with suitable anti-foaming properties are obtained. Commercial products among those disclosed in US Patent No. 3,367,867 have

usually a TBN of approx. 250.

Although the method described in US patent no.

3,367,867 is applicable for the production of products with TBN of 250 and acceptable viscosity, attempts have been made to adapt this technology for the production of group-II metal-overalkalised sulfurized alkylphenols with extremely high TBN of 300 and higher resulting in increased viscosity and increasing hydrolytic instability of the products. Consequently, there is a need to develop group-II metal-overalkalized sulfurized alkylphenols with ext. loud; TBN and suitable viscosity. There would also be a f.ord'el about such group.e-II metal-overalkalized sulfurized alkylphenols with high TBN

and suitable viscosity also were hydrolytically stable.

With the invention, the new oil-soluble group II metal over-alkalised sulfurized alkylphenols are now provided which have a total base number TBN of at least 300 and a viscosity of no more than 800 cSt at 100°C. They are characteristic in that they have a content of unsulfurized group II metal alkylphenol in the active ingredients that is less than 10 mol%.

The new oil-soluble, group-II metal-overalkalised sulfurized alkylphenols are surprisingly hydrolytically stable.

The group-II metal-overalkalized sulfurized alkylphenols according to the invention are conveniently produced by using a suitable alkylphenol and a "sulfurization catalyst" in the production of these additives. A particularly preferred catalyst is 2-mercaptobenzothiazole (MBT) and derivatives thereof.

As far as the inventor has been able to clarify, the use of a sulphurisation catalyst in the production of group-II metal over-alkalised sulphurised alkylphenols has not been previously described in the art. The previously known publications in the area include US Patent No.

4 100 085, where the use of ammonia or ammonium hydroxide as an activator in the production of over-alkalised sulphurised alkylphenols is explained. US Patent No. 4,212,752 also describes the use of certain amino activators, such as primary and secondary alkylamines, polyalkyleneamines, amino acids, etc., in the production of over-alkaline sulfurized alkylphenols.

The alkyl group in the alkyl phenol contains a sufficient number of carbon atoms to render the Group II metal over-alkalised sulfurized alkyl phenol oil soluble. In a preferred embodiment, the alkyl group in the alkylphenol contains from 25 to 100 mol% predominantly straight-chain alkyl groups with from 15 to 35 carbon atoms, while from 75 to 0 mol% of the alkyl groups are made up of polypropenyl groups with from 9 to 18 carbon atoms. More preferably, the alkyl group in the alkylphenol contains from 35 to 100 mol% predominantly straight chain alkyl groups with from 15 to 35 carbon atoms and from 65 to 0 mol% alkyl groups which are polypropenyl groups with from 9 to 18 carbon atoms. In yet another preferred embodiment, the alkyl group in the alkylphenol contains from 40 to 70 mol% predominantly straight chain alkyl groups with from 15 to 35 carbon atoms and from 60 to 30 mol% alkyl groups which are polypropenyl groups with from 9 to 18 carbon atoms. Most preferably, the alkyl group in the alkylphenol contains approx. 50 mol% predominantly straight-chain alkyl groups with 15 to 35 carbon atoms and approx.

50 mol% alkyl groups which are polypropenyl groups with from 9

to 18 carbon atoms.

Preferably, the group II metal-overalkalized sulfurized alkylphenols according to the invention have a total base number (TBN) of from 300 to 400, more preferably from 315 to 400, even more preferably from 315 to 360 and most preferably from 325 to 360.

Preferably, the group II metal is selected from among calcium, magnesium, barium and mixtures thereof. The most preferred group II metal is calcium.

As mentioned, the invention also relates to an application of

the above-described oil-soluble Group II metal over-alkalised sulfurized alkylphenol as a component of a lubricating oil blend or a lubricating oil concentrate.

The oil-soluble, group-II metal-over-alkalised sulfurized alkylphenol according to the invention imparts cleansing and dispersing properties to the lubricating oil and provides an alkalinity reserve in the oil. For this application, the amount of the oil-soluble Group II metal over-alkalised sulfurized alkylphenol ranges from 0.5 to 40% by weight of the total lubricant composition, although preferably it is from 1 to 25% by weight of the total lubricant composition.

The lubricating oil blends with the addition of the oil-soluble, Group II metal over-alkalised sulfurized alkylphenol are useful in diesel engines, gasoline engines and engines for marine use. When the lubricating oil mixtures are used in engines for marine use, the oil-soluble, group-II-metal-over-alkalised sulfurized alkylphenols are often used together with an oil-soluble, group-II-metal-over-alkalised, naturally occurring or synthetic hydrocarbyl sulphonate. A lubricating oil mixture containing an oil with lubricating oil viscosity and (a) from 0.5 to 40% by weight of an oil-soluble, group-II metal-overalkalised sulfurized alkylphenol according to the invention and (b) from 0.5 to 40% by weight of an oil-soluble, Group II metal over-alkaline, naturally occurring or synthetic hydrocarbyl sulfonate.

As used herein, the term "total base number" or "TBN" refers to the amount of base equivalent to the number of milligrams of KOH in 1 gram of sample. Thus, higher TBN numbers reflect more alkaline products and consequently a greater alkalinity reserve.

With the expression "hydrolytically stable", as used

in connection with group-II metal-overalkalised sulphurised alkylphenols, it is believed that mixtures containing these products will have the total base number reduced by less than approx. 25% by a modified ASTM D 2619 test. With this modified test, the hydrolytic stability of a product is measured by measuring its base loss when it is exposed to moisture. Greater base loss reflects poorer hydrolytic stability. The hydrolytic stability of the group-II metal-overalkalized sulfurized alkylphenols is an extremely important property, especially for use in crankcases in engines for marine use, where contact with water is common, see van der

Horst, Lubricant Engineering, "Development of Modern Lubricants for Medium-Speed Marine Diesel Engines" (1977); Thomas et al., "Modern Marine Diesel Engine Lubricants and their Development", Second International Lubricant Symposium, Cairo, Egypt (1979).

In the process for the production of overalkalised sulphurised alkylphenols, only the sulphurised group II metal alkylphenol can be overalkalised. Accordingly, it is desirable to keep the amount of sulphurized group II metal alkylphenol as high as possible in the reaction process. On the other hand, unsulfurized alkylphenol can form a group II metal salt, but this salt cannot be over-alkalised through the addition of Ca(OH)2 (related materials) and carbon dioxide. Accordingly, it is desirable to reduce the amount of unsulfurized group II metal alkylphenol in the reaction process.

The term "active ingredients" used in connection with the lubricating oil mixtures described here refers to the group II metal alkylphenol and the sulfurized group II metal alkylphenol, while the term "inactive ingredients" refers to unreacted alkylphenol as well as any diluent oil which had to be contained in the mixture.

The amount of sulfurized group II metal alkylphenol and likewise the amount of group II metal alkylphenol contained in the active ingredients can be determined using standard analytical methods. One method involves using dialysis combined with 3 H-NMR.

As the expression "predominantly straight-chain alkyl" is used here, it is to be understood as a predominantly linear alkyl group which may contain a certain amount of branching in the molecular structure.

The group-II metal-overalkalized sulfurized alkylphenols according to the invention are produced according to methods that correspond to the methods that have previously been described in the subject, except that a sulfurization catalyst is also used. In previously known methods for the production of group-II metal-overalkalized sulfurized alkylphenols, products can be obtained with a total base number as high as 300 or higher, one part of which has acceptable viscosity, while part of these products are hydrolytically unstable. The reason why hydrolytically stable overalkalized sulfurized alkylphenols with high TBN are not always obtained with the previously known methods is not immediately clear.

Based on a thorough investigation of this problem, it seems - without wishing to limit oneself to any particular theory - that the hydrolytic instability of products with high TBN is partly due to the fact that the active ingredients contain large amounts of unsulfurized group II metal alkylphenol . It seems that this incomplete incorporation of sulfur is more pronounced when high molar ratios between slaked lime and alkylphenol are used, namely molar ratios greater than 2. This means that slaked lime, sulfur and alkylphenol are introduced in the process for producing an over-alkalised, sulfurized alkylphenol in a reaction system. A sufficiently large amount of sulfur is used to transfer all the alkylphenol to sulfurized alkylphenol. When using a molar ratio between slaked lime and alkylphenol of 2 or less, the alkylphenol is usually transferred to sulphurised calcium alkylphenol, while with a molar ratio greater than 2 a product containing larger amounts of unsulphurised calcium alkylphenol is obtained. On the other hand, molar ratios of slaked lime to alkylphenol higher than 2 are usually required to achieve products with TBN numbers of 300+. Thereby the problem is clearly seen. When all other factors are kept equal, such as the amount of sulfur added, the amount of CC^ added, etc., to obtain products with a TBN of 300+, one must use a molar ratio of slaked lime to alkylphenol higher than 2, which always results in large amounts of unsulfurized calcium alkylphenol, which in its

in turn reduces the TBN incorporation, because it does not allow itself to be over-alkalised and tends to increase the viscosity of the product. The incomplete sulphurisation of the alkylphenol at high molar ratios between slaked lime and alkylphenol, i.e. molar ratios higher than 2, has so far not been recognised.

It has now been shown that by using a sulphurisation catalyst in the processes where more than 2 equivalents of slaked lime or other group II metal oxide or hydroxide are used, a strong increase in the amount of sulphurised group II metal is achieved alkylphenol in the active ingredients and a large reduction in the amount of unsulfurized group-II metal-alkylph enol in the active ingredients. The products with a high TBN according to the invention are characterized by the fact that they contain at least 90 mol% and preferably at least 95 mol% sulphurised group-II me-ethyl-alkylphenols in the active ingredients. Conversely, the products according to the invention will necessarily contain at most 10 mol% and preferably at most 5 mol% of the unsulfurized group II metal alkylphenols in the active ingredients. Due to the reduced amount of unsulfurized group-II metal alkylphenol in the active ingredients, it becomes possible to obtain products with a higher TBN. Moreover, these products will exhibit improved hydrolytic stability and likewise lower viscosity.

It has been shown that the new oil-soluble, group-II metal-over-alkalised sulphurised alkylphenols can be prepared by adding suitable amounts of a sulphurisation catalyst, sulphur, alkylphenol and a group-II metal oxide, hydroxide or -C to lubricating oil ^-C^-alkoxide and then carbonation with CC^. The reaction system will also contain a C2-C4 alkylene glycol (such as 1,3-propylene glycol, 1,4-butylene glycol, ethylene glycol, etc., the C2-C4 alkylene glycol being preferably ethylene glycol), a Group II metal overalkali , naturally occurring or synthetic hydrocarbyl sulfonate and a high molecular weight alcohol. The products obtained by this reaction are referred to in the art as group-II metal-overalkalized sulfurized alkylphenols. The group-II metal-overalkalized sulfurized alkylphenols according to the invention are characterized by having a total base number TBN of 300 or more and a viscosity of no more than 800 cSt at 100°C and contain no more than 10 mol% unsulfurized group-II metal alkylphenol.

The sulfurization catalyst catalyzes the binding of the sulfur to the alkylphenol. Suitable sulfurization catalysts include 2-mercaptobenzothiazole (MBT) and derivatives thereof, such as bis-(2,2'-benzothiazolyl) disulfide; 2(3H)-benzothiazolethione zinc salt; 2-benzothiazolyl-N,N'-diethylthiocarbamyl sulfide; 4-morpholinyl-2-benzothiazole disulfide, etc. Another suitable class of sulfurization catalysts includes dithiophosphates, such as zinc/diisopropyldithiophosphate; zinc di-n-butyl dithiophosphate, etc. Other suitable classes of sulfurization catalysts include thioureas, thiuramers, calcium polysulfide and the like. Specific such catalysts are N,N'-dibutylthiourea; ethylenethiourea; trimethylthiourea, dipentamethylenethiuram disulfide, dipentamethylenethioureatetrasulfide, dipentamethylenethioureahexasulfide, etc.

The sulfurization catalyst is usually used in an amount of from 0.5 to 10% by weight of the alkylphenol in the reaction system, preferably in an amount of from 1 to 2% by weight. According to a preferred embodiment, the sulfurization catalyst is added to the reaction mixture as a liquid. This can be done by dissolving the sulphurisation catalyst in molten sulfur or in the alkylphenol, so that a mixture is formed which is then added to the reaction.

Sulfur is usually used in an amount of from 2 to

4 moles per moles of the alkylphenol in the reaction system, preferably in an amount of from 2 to 3 moles per moles of alkylphenol. All allotropic forms of sulfur can be used. Alternatively, sulfur monochloride can be used instead of sulphur. For this purpose, sulfur monochloride shall be regarded as equivalent to sulphur. The sulfur can be used either in molten form or in solid form. The Group II metal oxide, hydroxide or C 1 -C 8 alkoxide used for the preparation of the Group II metal alkyl alkyl enol includes the oxides, hydroxides and alkoxides of calcium, strontium, barium and magnesium. However, calcium, barium and magnesium are preferred, with calcium being particularly preferred. The Group II metal oxide, hydroxide or C 1 -C 6 alkoxide is used in an amount relative to the amount of alkylphenol corresponding to a molar ratio greater than 2 and up to 4, although it is more preferred to use a molar ratio higher than 2 and up to 3.

Carbon dioxide is added to the reaction system in conjunction with the group II metal oxide, hydroxide or C 2 -C 8 alkoxide to form over-alkaline products and is usually used in an amount of from 1 to 3 mol per moles of alkylphenol, although it is preferred to add from 2 to 3 moles per mol alkylfe-

noi which is added to the reaction system.

The alkylphenol used is represented by the formula:

where R is an alkyl group containing a sufficiently large number of carbon atoms that the resulting Group II metal overalkalised sulfurized alkylphenol becomes oil soluble.

Preferably, R is alkyl where from 25 to 100 mol% of the alkyl group consists predominantly of straight chain alkyl with from 15 to 35 carbon atoms and from 75 to 0 mol% of the alkyl group consists of polypropylene with from 9 to 18 carbon atoms, although it is more preferred that R is alkyl where from 35 to 100 mol% of the alkyl group consists predominantly of straight chain alkyl with from 15 to 35 carbon atoms and from 65 to 0 mol%

of the alkyl group is made up of polypropenyl with from 9 to 18 carbon atoms. Use of increasing amounts of predominantly straight chain alkyl results in high TBN products which are typically characterized by lower viscosity. On the other hand, although polypropenylphenols are generally more economically advantageous than predominantly straight-chain alkylphenols, the use of more than 75 mol% polypropenylphenol in the preparation of Group II metal-overalkalised sulfurized alkylphenol will usually result in products having unacceptably high viscosity. However, using a mixture of from 75 mol% or less polypropenylphenol having 9 to 18 carbon atoms and from 25 mol% or more predominantly straight chain alkylphenol having from 15 to 35 carbon atoms will give more economical products of acceptable viscosity.

The alkylphenols of the above formula I are prepared by reacting the suitable olefin or the suitable olefin mixture with phenol in the presence of an alkylation catalyst at a temperature of from 60 to 200°C, preferably from 125 to 180°C, either without the use of a solvent or in a substantially inert solvent, at atmospheric pressure. A preferred alkylation catalyst is a sulfonic acid catalyst, such as Amberlys® 15, available from Rohm and Haas, Philadelphia, Pennsylvania. Molar ratios between the reactants can be used. Alternatively, a molar excess of phenol can be used, namely 2-2.5 equivalents of phenol for each equivalent of olefin, whereby unreacted phenol is recycled. The latter process gives maximum formation of monoalkyl phenol. Examples of inert solvents are benzene, toluene, chlorobenzene and diluent No. 250, which is a mixture of aromatics, paraffins and naphthenes.

The alkylphenols used are either ortho-alkylphenols

with the formula:

or para-alkylphenols with the formula:

Preferably, R is predominantly in the para position, with no more than 50 mol% of the alkyl group R being in the ortho position. More preferably, no more than 35 mol% of the alkyl group is in the ortho position. It is assumed that the p-alkylphenols (III) facilitate the production of highly overalkaline sulfurized group II metal alkylphenols. Consequently, it is desired to use an olefin which results in as high a content of para-alkylphenol in the alkylphenol as possible. While polypropylene usually binds to the para position, in this respect olefins that contain no branching will bind to both the ortho and para positions. A method to improve the para content of the alkylphenol produced from straight-chain olefins is to use a fraction with predominantly straight-chain olefin which contains some branching in the molecular structure at the double bond, such as structures VI and V:

ortho-alkylation and thereby results in improved para-substitution. Suitable predominantly straight-chain olefins are those in which 75-100% by number, preferably 85-100% by number,

of the olefin's individual carbon atoms are either primary (CH^-) or secondary (-CH2~) carbon atoms. Included within the terms primary and secondary olefins are α-olefins (-CH=CH2) and internal olefins (-CH=CH-). Conversely, such predominantly straight-chain olefins may contain 0-25 percent by number, although preferably 0-15 percent by number, of tertiary carbon atoms. Included among tertiary groups are trisubstituted vinyl groups (^rC=CH-) and vinylidine (^C=CH2).

Fractions with predominantly straight chain olefins are commercial products such as C₂₂-C₂₂ olefins, which are available from Ethyl Corporation, Baton Rouge, Louisiana. These olefins

are predominantly straight chain, with from 80 to 100 numerical percent of the carbon atoms in the olefins being either primary or secondary carbon atoms. About. 40 mol% of the olefins contained in the olefin fraction are branched olefins. This means that 40 mol% of the olefins are branched in that they have a trisubstituted-vinyl structure or a vinylidine structure, although they are otherwise predominantly straight-chain. Similarly, C24~<C>2g olefin fractions, obtainable from Chevron Chemical Corporation, San Francisco, USA, are also predominantly straight chain,

but they contain approx. 40 mol% or more branched olefin, containing predominantly vinylidine olefin. Straight chain olefins containing less than 5 mole percent branched olefins are available from Shell Chemical Company, Houston, Texas.

This should be the right time to distinguish between "predominantly straight-chain olefins containing 80-100 numerical percent of either primary or secondary carbon atoms in the olefin" and a fraction with predominantly straight-chain olefins where approx. 40 mol% of the olefins are branched". In the first case, the olefin is viewed on a molecular basis, and it is required that at least 80 percent by number of the carbon atoms must be primary or secondary. In this case, a branched olefin, such as trisubstituted vinyl or vinylidine, will nevertheless be predominantly straight chain, if a sufficient number of the remaining carbon atoms are primary or secondary, so that at least 80 percent by number of the carbon atoms in this olefin are primary or secondary.

A fraction with predominantly straight-chain olefins where approx. 40 mol% of the olefins are branched, seen on the other hand from a compositional point of view. This means that the fraction with predominantly straight-chain olefins may contain olefins such as α-olefins, internal olefins, trisubstituted vinyl and vinylidine. When the entire fraction of predominantly straight-chain olefins is considered, 40 mol% of the olefins are branched, i.e. made up of either trisubstituted vinyl or vinylidine, while the rest is made up of either α-olefins or internal olefins.

An alkylene glycol, such as ethylene glycol, a high molecular weight alcohol (usually decyl alcohol) and a group II metal overalkalised, naturally occurring or synthetic hydrocarbyl sulphonate are also used in the reaction for the production of the group II metal overalkalised sulfurized alkylphenols according to the invention.

The ethylene glycol is usually used in an amount corresponding to a molar ratio between ethylene glycol and the alkylphenol of from 1 to 4, although a molar ratio of from 2 to 3 is preferred. Alternatively, 2-ethylhexanol can be used together with ethylene glycol in weight ratios such as 80% by weight of 2-ethylhexanol and 20% by weight ethylene glycol.

The preferred high molecular alcohol is decyl alcohol, which is used in an amount corresponding to a molar ratio between decyl alcohol and the alkylphenol of from 0.5 to 4, preferably from 1 to 2.

The group-II metal over-alkalised naturally occurring or synthetic hydrocarbyl sulfonates can be either petroleum sulfonate, synthetically alkylated aromatic sulfonates, or aliphatic sulfonates such as those derived from polyisobutylene. These sulfonates are well known in the art. The hydrocar-butyl group must have a sufficient number of carbon atoms to make the sulfonate molecule oil-soluble. Preferably, the hydrocarbyl moiety has at least 20 carbon atoms and may be aromatic or aliphatic but is usually alkylaromatic. Most preferred are calcium, magnesium or barium sulphonates which have an aromatic character.

Certain sulfonates are typically produced by sulfonating a petroleum fraction that has aromatic groups, usually mono- or dialkylbenzene groups, and subsequent formation of the metal salt of the sulfonic acid material. Other starting materials for the preparation of these sulphonates include synthetically alkylated benzenes and aliphatic hydrocarbons prepared by polymerization of a mono- or diolefin, e.g. a polyisobutenyl group produced by polymerization of isobutene. The metal salts are formed directly or by reaction using well-known procedures.

The sulfonates are then overbased to form products with a total base number of up to 400 or more through the addition of carbon dioxide and a Group II metal hydroxide or oxide. Calcium hydroxide or calcium oxide is the most commonly used material for the formation of the most important overalkaline sulphonates. These materials are well known in the art.

In the case of group-II metal overalkaline, naturally occurring or synthetic hydrocarbylsulfonate, an amount of from 1 to 20% by weight of the alkylphenol is used, although it is preferred to use from 1 to 10% by weight. The above-described group-II metal-overalkalized, naturally occurring or synthetic hydrocarbyl sulfonate is also used in lubricating oil mixtures together with the group-II metal-overalkalized sulfurized alkylphenols, especially in mixtures for use in the crankcase in engines for marine use.

Instead of a group II metal over-alkalised, naturally occurring or synthetic hydrocarbyl sulphonate, an alkenyl succinimide can alternatively be used. Alkenylsuccini mites are well known in the art. The alkenyl succinimides are the reaction products of a polyolefin polymer substituted succinic anhydride with an amine, preferably a polyalkylene polyamine. The polyolefin polymer-substituted succinic anhydrides are obtained by reacting a polyolefin polymer or a derivative thereof with maleic anhydride. The succinic anhydride thus obtained is reacted with the amine compound. The preparation of the alkenyl succinimides has been described many times in the art, see e.g. US Patent Nos. 3,390,082, 3,219,666 and 3,172,892. By reducing the alkenyl-substituted succinic anhydride, the corresponding alkyl derivative is obtained. The alkylsuccinimides are to be understood as included within the scope of the term "alkenylsuccinimide".

A product which is predominantly made up of mono- or bis-succinimide can be prepared by regulating the molar ratio between the reactants. If e.g. 1 mol of amine is reacted with 1 mol of the alkenyl- or alkyl-substituted succinic anhydride, a product consisting predominantly of mono-succinimide will be obtained. If 2 mol of the succinic anhydride is reacted with 1 mol of polyamine, a bis-succinimide will be obtained.

The polyisobutene from which the polyisobutene-substituted succinic anhydride is obtained by polymerization of isobutene,

can vary greatly with regard to composition. The average number of carbon atoms can be from 30 or less to 250 or more, with a resulting number average molecular weight of from 400 or less to 3000 or more. Preferably, the average number of carbon atoms per polyisobutene molecules be from 50 to 100, while the polyisobutenes will have a number in the middle

molecular weight of from 600 to 1500. More preferably, the average number of carbon atoms in the polyisobutene molecule is in the range from 60 to 90, while the number average molecular weight is in the range from 800 to 1300. The polyisobutene is reacted with maleic anhydride according to well-known procedures for forming the polyisobutene-substituted succinic anhydrides.

To prepare the alkenyl succinimide, the substituted succinic anhydride is reacted with a polyalkylene polyamine to form the corresponding succinimide. Each alkylene radical in the polyalkylene polyamine usually has up to 8 carbon atoms. The number of alkylene radicals can be up to 8. Examples of the alkylene radical are ethylene, propylene, butylene, tri-methylene, tetramethylene, pentamethylene, hexamethylene, octa-methylene, etc. The number of amino groups is usually, but not necessarily, one more than the number of alkylene radicals present in the amine, which means that if a polyalkylene polyamine contains 3 alkylene radicals, it will usually contain 4 amino radicals. The number of amino radicals can be up to 9. Preferably, the alkylene radicals will contain from 2 to 4 carbon atoms and all amino groups will be primary or secondary. In this case, the number of amino groups exceeds the number of alkylene groups by 1. Preferably, the polyalkylene polyamine contains from 3 to 5 amino groups. Specific examples of the polyalkylene polyamines are ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, tripropylenetetramine, tetraethylenepentamine, trimethylenediamine, pentaethylenehexamine, di-(trimethylene)triamine, tri-(hexamethylene)tetramine, etc.

When used, the amount of alkenyl succinimide is from 1 to 20% by weight relative to the alkylphenol, although preferably from 1 to 10% by weight is used.

The reaction for the production of group-II metal-overalkalized sulfurized alkylphenols according to the invention is carried out by adding the alkylphenol, the group-II metal-overalkalized, naturally occurring or synthetic hydrocarbyl sulfonate, the high-molecular alcohol and the sulfurization catalyst in the appropriate proportions . The reaction is usually carried out in an inert diluent, such as a lubricating oil. Suitable lubricating oils for use as a diluent include solvent refined 100N, namely "Cit Con 100N", and hydrotreated 100N, namely "RLOP 100N". After combining the above-mentioned components, the system is heated to between 90 and 155°C with stirring, and sulfur and the group II metal oxide, hydroxide or C 1 -C 8 alkoxide are added, after which the ethylene glycol is added. Water of reaction is removed, the mixture is heated to approx. 175°C and carbon dioxide is added. Any unbound carbon dioxide is then removed, and the reaction system is heated to remove ethylene glycol, water and the high molecular weight alcohol, whereby a material is obtained which is referred to in the art as a group II metal over-alkalised sulphurised alkylphenol.

According to a preferred embodiment, it has been found that the addition of an emulsion breaking agent such as "Triton X-45" and "Triton X-100" can synergistically improve the hydrolytic stability of the Group II metal over-alkalized sulfurized alkylphenol. "Triton X-45" and "Triton X-100" are nonionic detergents useful as emulsion breakers available from Rohm and Haas, Philadelphia, PA. These emulsion breaking agents are ethoxylated p-octyl phenols. Another suitable emulsion breaking agent is e.g. "Igepal CO-610", available from GAF Corporation, New York, NY.

According to a preferred embodiment, the emulsion breaking agent and the sulfurization catalyst are combined, the aqueous solution containing calcium polysulphide and "Triton X-100". One such product is marketed by Chevron Chemical Company, San Francisco, CA under the trademark Orthorix<®>. Emulsion-breaking agents are preferably added in amounts of from 0.1 to 1% by weight, calculated on the amount of the alkylphenol, preferably in an amount of from 0.1 to 0.5% by weight.

In the lubricating oil mixtures added with the oil-soluble, group-II metal-over-alkalised sulphurised alkylphenol, a finished lubricating oil is used which can be a single-grade oil or a multi-grade oil (all-year oil). All-season lubricating oils are produced by adding viscosity index improvers (VI improvers; VI = Viscosity Index). Typical viscosity index improvers are polyalkyl methacrylates, ethylene-propylene copolymers, styrene-diene copolymers and the like. So-called "decorated" VI improvers, which have both viscosity index properties and dispersing properties, are also suitable for use in the lubricating oil blends.

The lubricating oil used in the lubricating oil mixture can be a mineral oil or synthetic oil with a viscosity suitable for use in the crankcase in engines with internal combustion, such as petrol engines and diesel engines, including engines for marine use. Crankcase lubricating oils typically have a viscosity of from 1300 cSt at -17.8°C to 24 cSt at 99°C. The lubricating oils may be derived from synthetic or naturally occurring sources. Mineral oil for use as a base oil in the blends includes paraffinic, naphthenic and other oils commonly used in lubricating oil blends. Synthetic oils include both synthetic hydrocarbon oils and synthetic esters. Suitable synthetic hydrocarbon oils include liquid polymers of α-olefins having suitable viscosity. Particularly useful are the hydrogenated, liquid oligomers of C 8 -C 8 -α-olefins, such as 1-decene trimer. Likewise, alkylbenzenes with suitable viscosity, such as didodecylbenzene, can be used. Suitable synthetic esters include the esters of monocarboxylic acids and polycarboxylic acids as well as monohydroxyalkanols and polyols. Typical examples are didodecyl adipate, pentaerythritoltet-racaproate, di-2-ethylhexyl adipate, dilauryl sebacate and the like. Complex esters produced from mixtures of mono- and dicarboxylic acids and mono- and dihydroxyalkanols can also be used.

Mixtures of hydrocarbon oils with synthetic oils

are also applicable. For example, mixtures of 10-25% by weight hydrogenated 1-decene trimer with 75-90% by weight 150 SUS (37.8°C) mineral oil provide an excellent lubricating oil base.

Also in lubricating oil additive concentrates, the oil-soluble, group-II metal-overalkalised sulphurised alkylphenol can be incorporated. The concentrate contains from 60 to 20% by weight of an oil with lubricating oil viscosity and from 40 to 80% by weight of an oil-soluble, hydrolytically stable group-II metal-over-alkaline sulfurized alkylphenol according to the invention.

Other additives which may be present in the composition include rust inhibitors, antifoam agents, corrosion inhibitors, metal deactivators, pour point depressants, antioxidants and a variety of other well known additives.

The following examples illustrate the invention.

It should be noted that two titrimeters were used to measure the TBN number in some of the examples. The TBN numbers listed were measured using one or the other of these titrimeters. The TBN numbers measured with these two titrimeters are no more than 3-5% apart. The TBN figures given are believed to be of an accuracy of - 5%. TBN numbers measured using both titrimeters are indicated in some of the examples.

First, however, the production of some starting materials used in the production of the new, oil-soluble, group-II metal-overalkalised sulfurized alkylphenols is illustrated.

Production 1

Preparation of a C^g-C^g- alkylphenol

To a 2-liter flask, which was equipped with a stirrer,

a Dean-Stark trap, a condenser and nitrogen inlet and outlet, 857 g of a mixture containing predominantly 0-C,n-olefins (olefin content: C,,-0.5%; C10-6.6%; C_n-26.2%;

loJU ib lo zU C22-27.7%; C24-18.2%; C26"9.0%; C2g-4.5%; C3Q-28%; higher

than C^q-4.5%), where at least 30 mol% of the olefins in the whole olefin fraction contain trisubstituted vinyl groups (available from Ethyl Corporation), 720 g of phenol and 55 g of a sulfonic acid cation exchange resin (polystyrene cross-linked with divinylbenzene) as catalyst ( Amberlyst ® 15 from Rohm and Haas, Philadelphia, Pennsylvania). The reaction mixture was heated at approx. 145°C for approx. 6 hours under stirring and under a nitrogen atmosphere. The reaction mixture was stripped by heating

under vacuum, and the resulting product was filtered hot over diatomaceous earth, whereby 947 g of a C^g-C^Q alkylphenol with a hydroxyl number of 118 and a para-alkylphenol content of 56% were obtained.

Manufacturing 2

Preparation of a C-,q-C,,g- alkylphenol

To a 2-liter flask, which was equipped with a stirrer,

a Dean-Stark trap, a condenser and nitrogen inlet and outlet, 674 g of a mixture of predominantly C20~C28~ olefins (olefin content: Clg-2%; C2Q- 28%; C22-19%; C24~13 %; C26-21%; C2g-11%; and higher than C3Q-6%), where at least 20 mol%

of the olefins in the entire olefin fraction contain vinylide groups (C-^-C, .-olefins and Cn .-C_ _-olefins can be obtained from Chev-

r 20 24 3 24 28

ron Chemical Company, San Francisco, CA and physically mixed with each other in equal molar amounts to form a ^2 0~C2 8~ olefin mixture), 211.5 g of phenol and 43 g of a sulfonic acid cation exchange resin (polystyrene cross-linked with divinylbenzene) as a catalyst (Amberlyst <®> 15 from Rohm and Haas, Philadelphia, PA). The reaction mixture was heated at 140°C for approx. 8 hours under stirring and under a nitrogen atmosphere. The reaction mixture was stripped by heating under vacuum, and the product was filtered hot over diatomaceous earth to give 574

g of a C2Q-C2g-alkylphenol with a hydroxyl number of 110 and a para-alkylphenol content of 56%.

Preparation 3

Preparation of tetrapropenylphenol

To a 2-liter flask, which was fitted with a stirrer,

a Dean-Stark trap, a condenser and nitrogen inlet and outlet, 567 g of tetrapropylene, 540 g of phenol and 72 g of a sulfonic acid cation exchange resin (polystyrene cross-linked

(R)

with divinylbenzene) as catalyst (Amberlyst ^15 from Rohm and Haas, Philadelphia, PA). The reaction mixture was heated at approx. 110°C for approx. 3 hours under stirring and under a nitrogen atmosphere. The reaction mixture was stripped by heating under vacuum, and the resulting product was filtered hot

over diatomaceous earth, whereby 626 g of tetrapropenylphenol with a hydroxyl number of 205 and a content of para-alkylphenol of 96% was obtained.

Manufacturing 4

Into a 0.5 liter three-necked flask, which was equipped with a stirrer, a Dean-Stark trap, a condenser and nitrogen inlet and outlet, 100 g of phenol was introduced. The system was heated to 55°C, after which 55 g of C 24 -C 2 g olefin, available from Chevron Chemical Company, San Francisco, CA, and 12.5 g of "Filtrol-13", which is an acid activated clay which can be obtained from Filtrol Corporation, Los Angeles, CA. 130.5 g of C18-C30 olefin were then added over the course of 1 hour,

which can be obtained from Ethyl Corp. Baton, Rouge, LA, while the system was heated at between 135°C and 145°C. The reaction was stopped, and filtration was carried out. The filtered product was transferred to a clean flask, placed under vacuum (approx. 50 mm Hg) and heated to 215°C with a light purge of nitrogen. The nitrogen supply was shut off, and the vacuum (about 50 mm Hg) was maintained at 215°C for 30 minutes, whereby an alkylphenol with a hydroxyl number of 106 was obtained.

Manufacturing 5

Production of calcium-overalkali-

sert hydrocarbyl sulfonate

A. Preparation of sodium hydrocarbyl sulfonate

Into a reaction vessel was introduced 646 g of a starting material (solvent-refined 500N lubricating oil, consisting of a mixture of alkyl aromatics, naphthenes and paraffins). At 23.9°C, 150.8 g of oleum (approx. 27.6% SO3) are introduced

1 the reaction vessel within 10 minutes. The reaction temperature is allowed to rise - usually to approx. 36.8°C. Next, 12.3 ml of water and 540 ml of "Chevron 2 65" diluent, which is a mixture of aromatics, naphthenes and paraffins, are added to the system. The system is maintained at 65.6°C

for 1 hour. At this point, 125 ml is added to the system

of an aqueous solution containing 25% by weight of sodium hydroxide. The reaction mixture is kept at 65.6°C for 1 hour. After the mixture has separated, the aqueous layer is removed and the organic solution is allowed to stand for at least 1 hour. After this time, further amounts of aqueous layer that may have separated are also removed. The system is stripped at 176.7°C and under atmospheric pressure, under sweep with a stream of air, whereby the sodium hydrocarbyl sulphonate is obtained, which is purified as follows: the sodium hydrocarbyl sulphonate is dissolved in 330

ml of aqueous secondary butyl alcohol. 160 ml of an aqueous solution containing 4% by weight sodium chloride is added to the system. The system is heated to 65.6°C and maintained at this temperature

for 2 hours. After the mixture has separated, the saline solution is removed. A further 80 ml of an aqueous solution containing 4% by weight of sodium chloride is then added to the system. The system is heated to 65.6°C and held at this temperature for 1 hour. After the mixture has separated, the saline solution is removed. 220 ml of water is added to the system, and the system is heated to 65.6°c. The system is kept at 65.6°C for 1 hour. Water and unsulphurised oil are then removed, whereby the aqueous solution of secondary butyl alcohol containing the sodium hydrocarbyl sulphonate is recovered.

B. Preparation of Calcium Hydrocarbylsulfonate

To the aqueous solution of secondary butyl alcohol containing the sodium hydrocarbyl sulphonate, which was prepared under point A. above, add 550 ml of a solution containing water, secondary butyl alcohol and calcium chloride (approx.

10% CaCl2). The system is heated to 65.6°C and held at this temperature for 1 hour. After the mixture has separated, the salt solution is removed. 340 ml of water and 170 ml of an aqueous solution containing 40% by weight calcium chloride are added to the system. The system is heated to 65.6°C and maintained at this temperature

for at least 1 hour. After the mixture has separated, the salt solution is removed. 340 ml of water and 170 ml of an aqueous solution containing 40% by weight calcium chloride are added to the system. The system is heated to 65.6°C and maintained at this temperature

for at least 1 hour. After the mixture has separated, the salt solution is removed. 340 ml of water is added to the system. The system is heated to 65.6°C and held at this temperature for 1 hour. After the mixture has separated, the aqueous layer is removed. Another 340; ml of water is then added to the system. The system is heated to 65.6°C and held at this temperature for 1 hour. After the mixture has separated, the aqueous layer is removed. The aqueous solution of secondary butyl alcohol is then stripped at elevated temperatures and reduced pressure, whereby calcium hydrocarbyl sulfonate is obtained.

C. Preparation of calcium overalkaline hydrocarbyl sulphonate

To a 500 ml 3-neck round flask equipped with a mechanical stirrer is added a sufficient amount of dilution oil to the calcium hydrocarbyl sulphonate prepared above to obtain 270 g of a mixture containing 1.65% by weight of calcium. 42.4 g of water and 10.8 g of calcium hydroxide are added to the system. A reflux condenser is attached to one side outlet, and a thermometer is attached to the other side outlet (neck) of the 3-neck round flask. The system is boiled with reflux cooling (approx. 98.9°C) and kept at this temperature for at least 1 hour. The reaction system is then distilled to a bottom temperature of 165.6°C/atmospheric pressure. The temperature is then increased to 204.4°C under vacuum (approx. 20 ml Hg). The system is then cooled to 148.9°C, and the vacuum is released. 20 g of diatomaceous earth is added to the product, and the product is filtered through a 6.35 ml pad of diatomaceous earth in a Buchner funnel, which is preheated before the filtration is carried out, whereby the desired compound is obtained, which usually has a total base number TBN of approx. 16.

Example 1

Production of calcium-overalkalized

sulfurized alkylphenol with a TBN of 340

Into a 2-litre 4-necked flask was introduced 196 g

tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 35<4> g <C>^g-C^Q<-a>lkylphenol, prepared in a similar manner as in Preparation 1, 410 g decyl alcohol, 20 g 2-mercap-

tobenzothiazole, 40 g of a calcium over-alkaline hydrocarbyl sulfonate, prepared in a similar manner as described in Preparation 5, and 200 g of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, at which time 296 g of CaOH)^ and 108 g of sulfur were added to the reaction system. The reaction system was then held at 90°C for 45 minutes. The reaction temperature was then increased over 15 minutes to 150°C. 206 g of ethylene glycol were then added over the course of 60 minutes through an addition funnel. After the addition of ethylene glycol was completed, the reaction temperature was increased to 160°C within 15 minutes, and this temperature was maintained for 1 hour. At this point, the stirring speed was increased to a moderate speed, and the reaction temperature was then increased at a rate of 5°C per minute. 20 minutes, until the reaction temperature had reached 175°C, after which 144 g of carbon dioxide was added to the reaction system through a flow meter during 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 mg Hg) for 30 minutes, yielding 1269 g of product which was purified by the addition of 3% by weight diatomaceous earth consisting of 50% "Hi-Flo "

and 50% "512 Celite", which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO, after which filtration was performed through a 6.35 ml pad of "Celite" on a Buchner funnel. The resulting product had a total base number TBN of 340 (324 as measured by the second titrimeter), a viscosity of 720 cSt at 100°C, a sulfur content of 4.4% by weight and a calcium content of 12.3% by weight.

Example 2

Preparation of a calcium-overalkaline

sulfurized alkylphenol with a TBN of 343

In a 37.8 liter stainless steel reactor, 3.53 kg of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 6.73 kg of C^g-C^Q-alkylphenol, prepared in a similar manner as in Preparation 1, 7 were introduced .6 kg of decyl alcohol, 380 g of 2-mercaptobenzothiazole, 760 g of calcium overbased hydrocarbyl sulfonate, prepared in a similar manner to Preparation 5, and 3.8 kg of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, at which time 5.62 kg of Ca(OH) 2 and 2.05 kg of sulfur were added to the reaction system. The reaction system was then held at 90°C for 45 minutes. The reaction temperature was then increased over the course of 15 minutes to 150°C, and 3.91 kg of ethylene glycol was then added over the course of 60 minutes via an addition flask. After the addition of ethylene glycol was completed, the reaction temperature was increased to 160°C and then held at this value for 1 hour. At this point, the stirring rate was increased, and the reaction temperature was then increased at a rate of 5°C per minute. 20 minutes, until the reaction temperature had reached 175°C, whereupon 2.74 kg of CO- was added to the reaction system over the course of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 ml Hg) for 30 minutes. The system was allowed to cool overnight, after which it was heated and stirred. The product was then purified by the addition of 3% by weight diatomaceous earth consisting of 50% "Hi-Flo" and 50% "512 Celite", which are commercial diatomaceous earth products obtained from Manville, Filtration and Minerals Division, Denver, CO. Filtration is then carried out, whereby a product is obtained with a total base number TBN of 343 (324 measured on the second titrimeter), a viscosity of 463 cSt at 100°C, a sulfur content of 4.4% by weight, a calcium content of 12, 4% by weight and an impure sediment of 1.6%.

Example 3

Into a 1 liter 4-necked flask were introduced 99 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 167 g of a C20-C2g alkylphenol, prepared in a similar manner as in Preparation 2, 210 g of decyl alcohol, 10 g of 2-mercaptobenzothiazole, 20 g of a calcium overbased hydrocarbyl sulfonate, prepared in a similar manner to Preparation 5, and 100 g of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, at which time 148 g of Ca(OH) 2 and 56 g of sublimed sulfur were added to the reaction system. The reaction mixture was then held at 90°C for 45 minutes. The reaction temperature was then increased over 15 minutes to 150°C, after which 103 g of ethylene glycol was added over 60 minutes. After the addition of the ethylene glycol was completed, the reaction temperature was increased to 160°C and held there for 1 hour. At this point, the reaction temperature was increased at a rate of 5°C per 20 minutes until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was added to the reaction system over the course of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 mm Hg) for 30 minutes. A deposit was removed and 800 ml of diluent "250", which is a mixture of aromatics, paraffins and naphthenes, was added to the system along with 3% by weight diatomaceous earth consisting of 50% "Hi-Flo" and 50% "512 Celite ", which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. The system was filtered through a 6.35 mm pad

of "Celite" placed in a Buchner funnel. Subsequently, the diluent was removed by stripping at elevated temperatures and reduced pressure, whereby 581 g of a calcium-overalkalised sulfurized alkylphenol with a total base number TBN of 328 (measured in the second titrimeter) was obtained,

a viscosity of 365 cSt at 100°C, a sulfur content of 3.96% by weight and a calcium content of 12.3% by weight.

Example 4

Into a 1 liter, 4-necked flask were introduced 99 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 167 g of a C20-C28 alkylphenol, prepared in a similar manner as in Preparation 2, 210 g of decyl alcohol, 10

q Orthor (a commercial calcium polysulfide product sold by Chevron Chemical Company, San Francisco, CA), 20 g of a calcium overalkaline hydrocarbyl sulfonate, prepared in a similar manner as described in Preparation 5, and 100

g "Cit-Con" 100N oil. The system was heated under heating to 90°C, at which time 148 g of Ca(OH) 2 and 56 g of sublimed sulfur were added to the reaction system. The reaction mixture was then held at 90°C for 45 minutes. The reaction temperature was then increased over 15 minutes to 150°C, after which

103 g of ethylene glycol was added over 60 minutes. After the addition of the ethylene glycol was completed, the reaction temperature was increased to 160°C and held there for 1 hour. From this point on, the reaction temperature was increased at a rate of 5°C

per 20 minutes, until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was added to the reaction system over a period of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 mm Hg) for 30 minutes. A precipitate was removed and 800 ml of Diluent No. 250, which is a mixture of aromatics, paraffins and naphthenes, was added to the system and likewise 3% by weight diatomaceous earth consisting of 50% "Hi-Flo",

a commercial diatomaceous earth product obtained from Manville, Filtration and Minerals Division, Denver, CO and 50% "512 Celite", a commercial diatomaceous earth product obtained from Manville, Filtration and Minerals Division, Denver CO. The system was filtered through a 6.35 mm pad of "Celite" placed in a Buchner funnel. The diluent was then removed by stripping at elevated temperatures and reduced pressures. 500 g of a calcium-overalkalised sulfurized alkylphenol with a total base number TBN of 344 (measured with the second titrimeter), a viscosity of 632 cSt at 100°C, a sulfur content of 3.31% by weight and a calcium content of 12.8% by weight.

Example 5 (Connection outside the definition in the requirements).

Into a 2 liter, 4-necked flask were introduced 99 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 167 g of a C2Q-C2g-alkylphenol, prepared in a similar manner as in Preparation 2, 210 g of decyl alcohol, 10

g of 2-mercaptobenzothiazole, 20 g of calcium-over-alkaline hydrocarbyl sulfonate, prepared in a similar manner to Preparation 5, and 100 g of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, and 138 g of calcined dolomite, Ca(OH)2, and 56 g of sublimed sulfur were then added to the reaction system. The reaction mixture was then held at 90°C for 45 minutes. The reaction temperature was then increased over a period of 15 minutes to 150°C, after which 103 g of ethylene glycol was added

over a period of 60 minutes. After the addition of the ethylene glycol was completed, the reaction temperature was increased to 160°C and held there for 1 hour. The reaction temperature was then increased at a rate of 5°C per 20 minutes, until the reaction temperature had reached 175°C, after which 74 g of carbon dioxide was added to the reaction system over a period of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 mm Hg) for 30 minutes. A precipitate was removed and 800 ml of "Chevron 250" diluent, which is a mixture of aromatics, paraffins and naphthenes, was added to the system and likewise 3% by weight diatomaceous earth consisting of 50% "Hi-Flo" and 50% "512 Celite", which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. The system was filtered through a 6.35 ml pad of "Celite" placed in a Buchner funnel. The diluent was then removed by stripping at elevated temperatures and reduced pressures. 2 80 g of a calcium-magnesium over-alkalised sulfurized alkylphenol with a total base number of 294 (measured with the second titrimeter), a viscosity of 154 cSt at 100°C, a sulfur content of 3.65% by weight, a calcium content of 7.62% by weight and a magnesium content of 2.14% by weight.

Example 6

Into a 1 liter 3-necked flask were introduced 104 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 187 g of a mixture of C1g-C30-alkylphenol and C-^-C-n-alkylphenol, prepared in a similar manner as in Preparation 4, 105 g of decyl alcohol, 10 g of 2-mercaptobenzothiazole, 20 g of calcium overalkaline hydrocarbyl sulfonate, prepared in a similar manner to Preparation 5, and 100 g of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, after which 148 g of Ca(OH) 2 and 56 g of sublimed sulfur were added to the reaction system. The reaction mixture was then held at 90°C for 45 minutes. The reaction temperature was then increased over a period of 15 minutes to 150°C, and 103 g of ethylene glycol was then added over a period of 60 minutes. After completion of the addition of the ethylene glycol, the reaction temperature was increased to 160°C and held there for 1 hour. The reaction temperature was then increased at a rate of 5°C per 20 minutes until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was added to the reaction system over a period of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 mm Hg) over a period of 30 minutes. A precipitate was removed and 800 ml of "Chevron 250" diluent which is a mixture of aromatics, paraffins and naphthenes was added to the system and likewise 3% by weight diatomaceous earth consisting of 50% "Hi-Flo" and 50% "512 Celite" , which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. The system was filtered through a 6.35 mm pad of "Celite" placed in a Buchner funnel. The diluent was then removed by stripping at elevated temperatures and reduced pressure to give 601 g of a calcium-over-alkali sulfurized alkylphenol with a total base number of 349 (a TBN of 324 as measured by the second titrimeter), a viscosity of 441 cSt at 100 °C, a sulfur content of 4.27% by weight and a calcium content of 12.4% by weight. ;Example 7 (Connection outside the definition in the requirements). ;Into a 1 liter, 3-necked flask were introduced 102 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 187 g of a mixture of C^g-C^Q-alkylphenol and C24-C2g-alkylphenol, prepared in a similar manner as in Preparation 4, 105 g of decyl alcohol, 20 g of 2-mercaptobenzothiazole, 20 g of a polyisobutenyl succinimide dispersant [prepared by reacting 1 mol of polyisobutenyl succinic anhydride, where the polyisobutenyl group has a number average molecular weight of approx. 950, with 0.87 mol of tetraethylene pentaamine and subsequent dilution to approx. 50% active ingredients with diluent oil - contains 2.1% nitrogen] and 100 g "Cit-Con" 100N. The system was heated with stirring to 90°C, after which 148 g of Ca(OH)2 and 56 g of sublimed sulfur were added to the reaction system. The reaction mixture was then held at 90°C for 45 minutes. The reaction temperature was then increased over a period of 15 minutes to 150°C. 103 g of ethylene glycol was then added over a period of 60 minutes. After the addition of the ethylene glycol was completed, the reaction temperature was increased to 160°C and held there for 1 hour. The reaction temperature was then increased at a rate of 5°C per 20 minutes, until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was added to the reaction system over a period of 3 hours. The reaction temperature was then increased to 195°C and the system was stripped under vacuum (about 10 mm Hg) over a period of 30 minutes. A precipitate was removed and 800 ml of "Chevron 250" diluent, which is a mixture of aromatics, paraffins and naphthenes, was added to the system and likewise 3% by weight of diatomaceous earth consisting of 50% "Hi-Flo" and 50% "Celite" , which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. The system was filtered through a 6.35 mm pad of "Celite" placed in a Buchner funnel. The diluent was then removed by stripping at elevated temperatures and reduced pressures to give a calcium-over-alkali sulfurized alkylphenol with a total base number of 352 (as measured by the first titrimeter), a viscosity of 893 cSt at 100°C, a sulfur content of 4 .02% by weight and a calcium content of 11.3% by weight. ;Example 8 ;In a mixer equipped with a hatch, a vent line, a top system connected to a vacuum line (jet vacuum) and a hot well line, the mixer is first ventilated over the top and into the hot well. The valve in the steam line is closed, and the mixer is then purged with a weak stream of nitrogen. ;With the heat sources switched off, 1351 liters of a tetrapropenylphenol, prepared in a similar manner as in Preparation 3 above and heated to 82.2°C, are added, and 1204 liters of "Cit-Con" 100N oil, of temperature 21.1°C, are added. There are added 2385 liters of a C2Q-C2g-alkyphenol, prepared in a similar manner as in Preparation 2 above and heated to 65.6°C, 265.0 liters of a calcium overalkaline hydrocarbyl sulphonate, prepared in a similar manner as in Preparation 5 and heated to 93.3°C, and 3278 liters of decyl alcohol of 21.1°C. ;The stirring is started, and the temperature of the mixer is set to 65.6°C. After shutting off the nitrogen, the hatch is opened, and 124.7 kg of 2-mercaptobenzothiazole are added to the system. After closing the hatch, the system is heated at 93.3°C for 4 hours. ;After making sure that the mixer has ventilation circulation to the hot well line, cool the system to 79.4°C. While the system is being stirred, 1819 kg of slaked lime is added. The steam line is opened for ventilation through the condenser and water receiver to the jet nozzles. The line between the mixer and the heating well is closed, and the vacuum is set to 254 mm Hg. Heating is carried out to 126.7°C. 602 kg of sulfur is added, and heating is carried out to 121.1°C. It is then heated to 148.9°C over a period of 1 hour. At this point, 1037 1 ethylene glycol is added over a period of 60 minutes. The addition of ethylene glycol is started slowly, and after completion of the addition of ethylene glycol, the system is heated to 168.3°c over a period of 1 hour. ; 762 kg of carbon dioxide is then added over a period of 2 hours and 48 minutes. After the addition of carbon dioxide, the temperature is allowed to rise to 176.7°C. After the addition of carbon dioxide is complete, a full vacuum of at least 711 mm Hg is applied. Heating is carried out to 204.4°C. These conditions are maintained for 30 minutes, starting as soon as the temperature of 201.6°C is reached. Cooling is then carried out to 176.7°C, and the vacuum is broken with nitrogen, while the pressure is adjusted to an overpressure of 0.35 kg/cm 2. This results in a calcium-over-alkalised sulphurised alkylphenol with a total base number TBN of 327, a viscosity of 1375 cSt at 100°C and a content of 12.3% calcium, 3.70% sulfur and 0.8% impure precipitate. Filtration is carried out through diatomaceous earth and dilution with 5% by weight of 130 N oil, whereby a calcium-overalkalised sulphurised alkylphenol is obtained with a TBN of 312, a viscosity of 660 cSt at 100°C and a content of 11.6% calcium, 3.32% sulfur and 0.02% sediment. ;Comparative example A ;(Comparison with examples 3 and 4) ;Into a 1 liter 4-necked flask were introduced 99 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 167 g of a C2Q-C2g-alkylphenol, prepared in a similar manner manner as in Preparation 2, 210 g of decyl alcohol, 20 g of a calcium over-alkaline hydrocarbyl sulfonate, prepared in a similar manner to Preparation 5, and 100 g of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, at which time 148 g of Ca(OH) 2 and 56 g of sublimed sulfur were added to the reaction system. The reaction mixture was then held at 90°C for 45 minutes. The reaction temperature was then increased over a period of 15 minutes to 150°C, after which 103 g of ethylene glycol was added over a period of 60 minutes. After completion of the addition of the ethylene glycol, the reaction temperature was increased to 160°C and held there for 1 hour. The reaction temperature was then increased at a rate of 5°C per 20 minutes, until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was introduced into the reaction system over a period of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 ml Hg) over a period of 30 minutes. A precipitate was removed and 800 ml of Diluent No. 250, which is a mixture of aromatics, paraffins and naphthenes, was added to the system as well as 3% by weight diatomaceous earth consisting of 50% "Hi-Flo", a commercially available diatomaceous earth product from Manville, Filtration and Minerals Division, Denver, CO, and 50% "512 Celite", a commercial diatomaceous earth product available from Manville, Filtration and Minerals Division, Denver, CO. The system was filtered through a 6.35 mm pad of "Celite" placed in a Buchner funnel. The diluent was then removed by stripping at elevated temperatures and reduced pressures. 377 g of a calcium-over-alkalised sulfurized alkylphenol with a total base number of 296, a viscosity of 667 cSt at 100°C, a sulfur content of 3.28% by weight (average of two trials), and a calcium content of 11 .6% by weight. ;Comparative example B ;(Comparison with example 6) ;Into a 1 liter 3-necked flask were introduced 102 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 187 g of a mixture of C^g-C^Q-alkylphenol and < C>24<-C>2Q-alkylphenol prepared in a similar manner as in Preparation 4, 105 g of decyl alcohol, 20 g of calcium overalkaline hydrocarabyl sulfonate, prepared in a similar manner as in Preparation 5, and 100 g of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, after which 148 g of slaked lime, Ca(OH)2, and 56 g of sublimed sulfur were added to the reaction system. The reaction mixture was then held at 90°C for 45 minutes. The reaction temperature was then increased over 15 minutes to 150°C, after which 103 g of ethylene glycol was added over 60 minutes. After the addition of the ethylene glycol was completed, the reaction temperature was increased to 160°C and held there for 1 hour. The reaction temperature was then increased at a rate of 5°C per 20 minutes, until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was added to the reaction system over a period of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 mm Hg) over a period of 30 minutes. A precipitate was removed and 800 ml of "Chevron 250" diluent, which is a mixture of aromatics, paraffins and naphthenes, was added to the system and likewise 3% by weight diatomaceous earth consisting of 50% "Hi-Flo" and 50% "512 Celite", which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. The system was filtered through a 6.35 mm pad of "Celite" placed in a Buchner funnel. The diluent was then removed by stripping at elevated temperatures and reduced pressures. There was thereby obtained 525 g of a calcium-overalkalized sulfurized alkylphenol with a total base number of 329 (327 measured on a second titrimeter), a viscosity of 1190 cSt at 100°C, a sulfur content of 3.75% by weight, a calcium content of 12.2% by weight and a content of impure sediment of 5.2% by weight. ;Comparative example C ;(Comparison with example 7) ;Into a 1 liter 3-necked flask were introduced 102 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 187 g of a mixture of C1g-C30-alkylphenol and C24-C28 -alkylphenol, prepared in a similar way as in Preparation 4, 105 g of decyl alcohol, 20 g of a polyisobutenyl succinimide dispersant [prepared by reacting 1 mol of polyisobutenyl succinic anhydride, where the polyisobutenyl group has a number-average molecular weight of approx. 950, with 0.87 mol tetraethylenepentamine and subsequent dilution to approx. ;50% active ingredients in diluent oil; contains 2.1% nitrogen] and 100 g "Cit-Con" 100N oil. The system was heated with stirring to 90°C, after which 148 g of slaked lime, Ca(OH)2, and 56 g of sublimed sulfur were added to the reaction system. The reaction temperature was then maintained at 90°C for 45 minutes. The reaction temperature was then increased over 15 minutes to 150°C, after which 103 g of ethylene glycol was added over a period of 60 minutes. After the addition of the ethylene glycol was completed, the reaction temperature was increased to 160°C and held there for 1 hour. The reaction temperature was then increased at a rate of 5°C per 20 minutes, until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was introduced into the reaction system over a period of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (about 10 mm Hg) for 30 minutes. A precipitate was removed and 800 ml of "Chevron 250" diluent, which is a mixture of aromatics, paraffins and naphthenes, was added to the system and likewise 3% by weight diatomaceous earth consisting of 50% "Hi-Flo" 50% "512 Celite ", which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. The system was filtered through a 6.35 mm pad of "Celite" placed in a Buchner funnel. Then the diluent is removed by stripping at elevated temperatures and reduced pressure. A calcium-overalkalised sulfurized alkylphenol with a total base number of 331 (measured on the first titrimeter), a viscosity of 907 cSt at 100°C, a sulfur content of 3.94% by weight and a calcium content of 10 .3% by weight. ;Comparative example D ;(Comparison with example 1) ;Into a 1 liter 4-necked flask were introduced 104 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 178 g of C^g-C^g-alkylphenol, prepared in a similar manner as in Preparation 1, 105 g of decyl alcohol, 20 g of a calcium overbased hydrocarbyl sulfonate, prepared in a similar manner to Preparation 5, and 100 g of "Cit-Con" 100N oil. The system was heated with stirring to 90°C, after which 148 g of Ca(OH)2 and 56 g of sublimed sulfur were added to the reaction system. The reaction system was then held at 90°C for 45 minutes. The reaction temperature was then increased over 15 minutes to 150°C, after which 103 g of ethylene glycol was added over a period of 60 minutes through an addition funnel. After the addition of ethylene glycol was completed, the reaction temperature was increased to 160°C within 15 minutes and held there for 1 hour. Next, the rate at which the reaction mixture was stirred was increased to a moderate rate, and the reaction temperature was then increased at a rate of 5°C per minute. 20 minutes, until the reaction temperature had reached 175°C, after which 72 g of carbon dioxide was added to the reaction system through a flow meter over a period of 3 hours. The reaction temperature was then increased to 195°C, and the system was stripped under vacuum (10 mm Hg) for 30 minutes, yielding 608 g of product, which was purified by the addition of 3% by weight diatomaceous earth consisting of 50% "Hi-Flo" and 50% "Celite 512", which are commercial diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. Filtration was then carried out through a 6.35 mm pad of "Celite" placed in a Buchner funnel. The resulting product had a total base number of 336 (a TBN of 335 was measured on the second titrimeter), a viscosity of 1323 cSt at 100°C, a sulfur content of 3.95% and a calcium content of 12.5%. In the table I below, some of the examples are compared with the comparison examples. Table I shows that, under otherwise equal conditions, the use of a sulphurisation catalyst will usually result in a product with a higher TBN and lower viscosity as well as a lower content of impure sediment than is obtained without the use of any sulphurisation catalyst. In Tables II and III below examples 9-12 illustrate further products according to the invention with high TBN and low viscosity. These products were produced in a similar way as described in the above examples 1-8. ;The group II metal overalkalized sulfurized alkylphenols according to the invention are characterized by the fact that they contain at least 90% and preferably at least 95% sulfurized group II metal alkylphenols in the active ingredients and at most 10%, preferably at most 5%, unsulfurized group II metal alkylphenols in the active ingredients. Previously known group-II metal-overalkalized sulfurized alkylphenols with a TBN of 300+ contain substantially more than 10% unsulfurized group-II metal-alkylphenol in the active ingredients. Previously known mixtures can be prepared either according to a one-step method, such as in comparative examples A-D above, or according to a two-step method as shown in comparative example E below. ;Comparative Example E ;Step 1 - Preparation of the Calcium Salt of Sulfurized Alkyl Phenol. ;Into a 3 liter 3-necked flask were introduced 529 g of tetrapropenylphenol, prepared in a similar manner as in Preparation 3, 274 g of a <C>18-C30<-a>alkylphenol, prepared in a similar manner as in Preparation 1, and 250 g "Cit-Con" 100N. The system was heated to 90°C, and 50 g of Ca(OH)2 and 112.5 g of sublimed sulfur were added. The system was heated to 175°C, and 32.5 g of ethylene glycol was added over a period of 30 minutes. The system was held at 175°C for 1 hour, after which a vacuum (about 10 mm Hg) was applied for 4 hours to strip off the ethylene glycol. 127.5 g of C₁-C₂g-α-olefin derived from cracked wax was added at 135°C along with 122.5 g of "Cit-Con" 100N, and the system was heated for 8 hours under a nitrogen atmosphere. The product was filtered through a 50:50 mixture of "Hi-Flo" and "Celite 512" diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO, yielding 1351 g of product with a total base number of 63, and which contained 1.94 wt% calcium and 4.47 wt% sulphur. ;Step 2 - Preparation of the calcium salt of overalkaline sulfurized alkylphenol. Into a 1 liter 3-necked flask were introduced 380 g of the product prepared in step 1, 20 g of a polyisobutenyl-succinimide dispersant [prepared by reacting 1 mol of polyisobutenyl succinic anhydride, where the polyisobutenyl group has a number average molecular weight of 950, with 0.87 mol tetraethylenepentamine and subsequent dilution to approx. 50% active ingredients with diluent oil] and 48 g of decyl alcohol, and the system was heated to 90°C. 106 g of Ca(OH)2 was added while the system was heated to 150°C. 74.5 g of ethylene glycol was slowly added, and the system was heated to 175°C. 61 g of carbon dioxide was then added over a period of 4 hours. The product was stripped under vacuum (about 10 mm Hg) at 190°C and filtered through a 50:50 mixture of "Hi-Flo" and "Celite 512", which are diatomaceous earth products available from Manville, Filtration and Minerals Division, Denver, CO. 485 g of a calcium-overalkalized sulfurized alkylphenol with a total base number of 334, a viscosity of 2405 cSt at 100°C, a sulfur content of 2.7% by weight and a calcium content of 12.1% by weight were thereby obtained. ;The lubricating oil mixture added with the oil-soluble, group-II metal-overalkalised sulfurized alkylphenol according to the invention and likewise previously known mixtures were analyzed using the following dialysis and H-NMR technique (Example 13) to determine the content of sulfurized group-II -metal-alkylphenol and of unsulfurized group-II metal-alkylphenol. ;Example 13 ;The lubricating oil mixture added with the oil-soluble, group-II metal-over-alkalised sulfurized alkylphenol according to the invention and similarly previously known mixtures were analyzed in the following manner. 50 g of group II metal over-alkalised sulfurized alkyphenol additive is weighed into a dialysis bag (prophylactic bag Ramses No. 18) rinsed in acetone. The bag is suspended in a 2 liter beaker containing 1.5 liters of 60 vol% methyl ethyl ketone (MEK) and 40 vol% t-butanol. The solution is stirred with a magnetic stirrer at ambient temperature. The solution is replaced every 24 hours for 7 days. The pooled dialysate solutions are stripped using a rotary evaporator and finally at a vacuum of 1 mm Hg at 85°C, yielding a product which is weighed. This product contains diluent oil ("Cit-Con" 100N) and unsulfurized alkylphenol starting material, which is detected by H-NMR in hexamethylphosformamide (HMPA) as solvent. In this solvent, the unsulfurized alkylphenol exhibits peaks in ^ The H-NMR spectrum at 10.00-10.11 ppm relative to tetramethylsilane (TMS), which is added as an internal standard. The alkylphenols according to Preparations 1-4 exhibit this ``H-NMR peak and are therefore considered to be constituted by unsulfurized alkylphenol. ;The solid residue in the dialysis bag is weighed. This residue contains more than 95% of all the calcium (or other Group II metal) in the original Group II metal over-alkalized sulfurized alkylphenol products and is referred to as the "active ingredients". This residue or "active ingredient" contains the sulfurized, overalkaline calcium alkylphenol and optionally unsulphurized calcium alkylphenol. The composition of the "active ingredients" is determined by means of the following analysis. The "active ingredients" are dissolved in a mixture of hexanes and then treated with 100 ml of concentrated hydrochloric acid in 100% ethanol. After the addition of hydrochloric acid, the mixture is stirred for 1 hour at ambient temperature to achieve complete decalcification of the "active ingredients". The liberated sulphurised alkylphenol and in some cases the unsulfurised alkylphenol is obtained by washing the hexane solution with water, washing the hexane solution with 10 % aqueous sodium carbonate and subsequent stripping of the hexane solution at 120 mm Hg at 80-85°C , whereby the de-calcified "active ingredients" are obtained as a product, which product is analyzed by ^H-NMR in hexamethylphosphoramide (HMPA) as a solvent containing TMS as an internal standard. The unsulfurized alkylphenol exhibits a peak at 10.00-10.11, which is designated the Sg peak. The sulphurised alkylphenols show peaks at 10.40-10.50 for the alkylphenols with a monosulphide bridge, which peaks are called the S^-peak. The sulphurised alkylphenols also show peaks at 10.90-11.00 for the alkylphenols with a disulphide bridge, which peaks are called the S2 peak. The areas of these peaks are obtained by integration in a "Varian T60" or General Electric "QE" 300 MHz NMR spectrometer. The integrated areas are converted to mole percent by dividing the integrated peak areas for S, and S2 by 2 (assuming dimeric structures). As the term "active ingredients" is used here, it is an expression of the amount of unsulfurized group II metal alkylphenol and sulfurized group II metal alkylphenol contained in the mixture, which can be determined using this procedure and likewise by means of other standard analysis methods. ;;It will be seen from table V below that the content of unsulfurized group-II metal alkylphenol is disadvantageous in a group-II metal-over-alkalised sulfurized alkylphenol mixture. As can be seen from this table, in particular the calcium salt of the alkylphenol according to Preparation 3 is extremely viscous, and if this is present in significant quantities, it will therefore increase the viscosity of the Group II metal-based sulfurized alkylphenol mixture to a significant extent. Likewise, the calcium salt of the alkylphenol according to Preparation 4 does not contribute very much to the total base number of the mixture, although it is much less viscous than the calcium salt of the alkylphenol according to Preparation 3. If it is present in a significant amount, it will consequently reduce the total base number of the group II-metal-overalkalized sulfurized alkylphenol mixture to a significant extent. On the other hand, the group II metal over-alkalised sulfurized alkylphenols of the invention contain only small amounts of unsulfurized group II metal alkylphenols or none, and consequently have a high total base number and acceptable viscosity. The results for example 6 are included for illustration purposes. ;;Example 19 ;A pre-blended oil containing a Group-II metal-over-alkaline sulfurized alkylphenol according to the invention was tested using a "Sequence-V-D" test method (considered to be an ASTM standard). In this method, a Ford 2.3 liter four-cylinder engine from the make Pinto is used. The test method simulates a type of stressful driving which is characterized by a combination of city driving at low speed, at low temperatures and with a lot of stopping, and moderate driving on the motorway. The effectiveness of the additives in the oil is measured by the protection the additives provide against deposits of sludge and varnish on a scale from 0 to 10, where 0 indicates black deposits and 10 indicates the absence of varnish or sludge. The results are listed in Table VI. The "Sequence-V-D" test was performed using a product prepared in a similar manner as described in Examples 1 and 2. These products were compared to a commercial sulfurized calcium alkylphenol with TBN of 250 prepared from alkylphenol as described in Preparation 3. The composition of the premixed oils was: 5.25% of a bis-polyisobutenyl succinimide, 20 mmbl per kg of an over-alkaline hydrocarbyl sulphonate as described in Preparation 5, 20 mmol per kg of a hydrocarbyl sulphonate with ppm of 320.82 mmol per kilo of the product prepared as described in examples 1 and 2, 20 mmol per kilograms of a zinc dithiophosphate, 20% of a commercial viscosity index improver in 150N/600N Exxon base oil consisting of 85% by weight 150N and 15% by weight. %' 600N. The comparison mixture had the same composition as above, except that 82 mmol per kilo of a commercial fin* with. TBN of 2:5>0, prepared from the alkyphenol described in Preparation, 3 was used instead of the phenate with high TBN prepared as described in examples 1 and 2.

Claims (7)

1. Oil-soluble, group-II metal-overalkalised sulfurized alkylphenol, with a total base number TBN of at least 300 and a viscosity of at most 800 cSt at 100°C, characterized in that it has a content of unsulfurized group-II metal alkylphenol in the active ingredients which is less than 10 mol%. 2. Alkylphenol according to claim 1, characterized in that the alkyl group consists of predominantly straight-chain alkyl with 15-35 carbon atoms for 25-100 mole percent and for 75-0 mole percent of polypropylene with from 9 to 18 carbon atoms. 3. Alkylphenol according to claim 2, characterized in that the alkyl group for 40-70 mole percent is made up of predominantly straight-chain alkyl with 15-35 carbon atoms and for 60-30 mole percent of polypropylene with 9-18 carbon atoms. 4. Alkylphenol according to claim 3, characterized in that the alkyl group consists of approx. 50 mol% predominantly straight-chain alkyl with 15-35 carbon atoms and approx. 50 mol% polypropylene with 9-18 carbon atoms. 5. Alkylphenol according to claims 1-4, characterized in that the group II metal is selected from among calcium, magnesium and barium. 6. Alkylphenol according to claim 5, characterized in that the group-II metal is calcium. 7. Use of an oil-soluble, group-II metal-overalkalised sulfurized alkylphenol according to claims 1-6 as a component of a lubricating oil mixture or a lubricating oil concentrate.