NO169904B - SMOEREMIDDELPREPARAT - Google Patents

Description

The present invention relates to a sulphur-containing lubricant preparation comprising a main quantity of an oil with lubricant partial viscosity and a smaller quantity of an oil-soluble preparation.

More particularly, the invention relates to preparations as mentioned with little or no phosphorus.

Various preparations produced by sulphurisation of organic compounds and more particularly olefins and olefin-containing compounds are known in this technique, in the same way as lubricants containing these products. Typical sulfurized preparations prepared by reacting olefins such as isobutene, diisobutene and triisobutene with sulfur under various conditions are described, for example, in "Chemical Review", 65, 237 (1965). Other references describe the reaction of such olefins with hydrogen sulphide and elemental sulfur to thereby form mainly mercaptans in which sulphides, disulphides and higher polysulphides are also formed as by-products, here reference should be made to "J. Am. Chem. Soc", 60, 2452 (1938 ), as well as US-PS 3,221,056, 3,419,614 and 4,191,659. TJS-PS 3,419,614 describes a method for increasing the yield of mercaptan by carrying out the reactions between olefin and hydrogen sulphide and sulfur at high temperature in the presence of various basic substances. US-PS 4,191,659 describes the preparation of sulfurized preparations by reaction at superatmospheric pressure of olefins with a mixture of sulfur and hydrogen sulfide in the presence of a catalyst followed by treatment with an alkali metal sulfide. The use of sulphurised natural and synthetic oils as additives in lubricating mixtures is proposed in the prior art, for example in TJS-PS 2,999,813 and 4,360,438.

It is also known that Diels-Alder adducts can be sulfurized to form sulfur-containing preparations which are particularly useful as extreme pressure and antiwear additives in various lubricating oils. TJS-PS 3,632,566 and TJS-Reissue 27,331 describe such sulfurated Diels-Ålder adducts and lubricants containing said adducts. In these patents, the ratio of sulfur to Diels-Alder adduct is described at a molar ratio of from 0.5:1.0 to 10.0:1.0. The patents suggest that it is usually desirable to incorporate as much stable sulfur into the compound as possible, and therefore a molar excess of sulfur is usually used. The described lubricating mixtures may contain other additives which are usually used to improve the properties of the lubricating mixtures such as dispersants, detergents, extreme pressure agents and further oxidation and corrosion inhibiting agents. For certain lubricant applications, however, the sulfur-containing compositions described above are not fully satisfactory as multi-purpose additives.

Organophosphorus and metal organophosphorus compounds are used extensively in lubricating oils as extreme pressure agents and antiwear agents. Examples of silk compounds are: phosphosulphured hydrocarbons such as the reaction product between phosphorus sulphide and turpentine; phosphoric esters including dihydrocarbon and trihydrocarbon phosphites; and metal phosphorodithioates such as zinc dialkyl phosphorodithioates. Due to the toxicological problems in connection with the use of organophosphorus compounds and especially with metal dialkylphosphorus and dithioates, there is a need to develop lubricating oil mixtures containing low levels of phosphorus but still with acceptable oxidation inhibition and antiwear properties. Lubricants containing low levels of phosphorus are also desirable based on phosphorus' tendency to poison catalytic converters used to control emissions from petrol engines.

Polyvalent salts of dithiocarbamic acids are known and have been described as useful oil additives because they serve a dual function, namely sequestering unwanted metal components in the oil and because they act as antioxidants. Lubricating oil blends comprising combinations of various polyvalent metal dithiocarbamates with other chemical additives have been described which exhibit desirable property-enhancing characteristics when added to the lubricating oil in combination with the dithiocarbamates. For example, US-PS 2,999,813 describes a lubricating composition comprising a sulfurized mineral oil and a polyvalent metal dithiocarbamate. Preferably, the mixture also comprises a lead soap of a naphthenic fatty acid. The production of lubricating mixtures comprising mineral oil, metal salts of dithiocarbamic acids and coupling agents such as alcohols, esters, ketones and other stable oxygen-containing substances is described in US-PS 2,265,851. US-PS 2,394,536 describes lubricating oil compositions containing the combination of organic sulfides and salts of dithiocarbamic acids. Organic sulfides are generally represented by the formula R^(S)nR2 where Ri and R2 are aliphatic groups and n equals 1, 2 or 3.

US-PS 2,805,996 describes the use of amine-dithiocarbamate complexes in lubricating oil mixtures and US-PS 2,947,695 describes the advantages of using mixtures of polyvalent metal dithiocarbamates in the production of oil-soluble additive preparations that can be used in the production of lubricating oils.

The present invention aims to improve the known technique and thus relates to oil-soluble lubricant preparations of the type mentioned at the outset, and these preparations are characterized by the fact that they contain:

(A) at least one metal salt of at least one dithiocarbamic acid of the formula

where R 1 and R 2 are independently hydrocarbon groups in which the total number of carbon atoms in R 1 and R 2 is sufficient to make the metal salt oil-soluble; and

(B) at least one oil-soluble sulfurized olefin comprising the reaction product of sulfur and a Diels-Ålder adduct in

a mole ratio less than 1.7:1, where the weight ratio (A):(B)

lies within the range of 1:10 to 50:1; and

(C) at least one auxiliary corrosion inhibitor in the form of an oil-soluble derivative of a dimercaptothiadiazole, wherein

the weight ratio (C):(A)+(B) is 0.001:1 to 0.5:1;

and the lubricant composition contains less than 0.1 wt-£ phosphorus.

These preparations are produced by combining a larger quantity of an oil with lubricant viscosity with a smaller quantity of an oil-soluble preparation as described under points (A), (B) and (C) above.

The sulfurized organic compounds are generally selected from among aromatic, alkyl or alkenyl sulfides or polysulfides, sulfurized olefins, sulfurized carboxylic acid esters, sulfurized ester olefins, sulfurized oils or mixtures thereof. Special examples of the additional corrosion inhibitor are the oil-soluble derivatives of dimercaptothiadiazoles. The preparations according to the invention can also contain at least one oil-soluble dispersant or a detergent. The oil-soluble preparations according to the invention are usable especially in lubricating oil formulations which contain little or no phosphorus.

Component (A) in that the oil-soluble preparation according to the invention is at least one metal salt of at least one dithiocarbamic acid with the formula where Ri and Rg are each independently hydrocarbyl groups in which the total number of carbon atoms in R^ and Rg is sufficient to make the metal salt oil-soluble. The hydrocarbyl groups R 1 and R 8 can be alkyl, cycloalkyl, aryl, alkaryl or aralkyl groups. Rj and Rg taken together may represent the group consisting of polymethylene- and alkyl-substituted polymethylene groups which thereby form a cyclic compound with the nitrogen. In general, the alkyl group will contain at least two carbon atoms. The metal in the metal salt can be a monovalent or a polyvalent metal, although polyvalent metals are preferred because it is generally difficult to prepare oil solutions containing the desired amounts of alkali metal salts. Suitable polyvalent metals are, for example, the alkaline earth metals, zinc, cadmium, magnesium, tin, molybdenum, iron, copper, nickel, cobalt, chromium, lead and so on. Group II metals are preferred.

When choosing the metal salt of a dithiocarbamic acid to be used in the oil-soluble preparations according to the invention, R^, Rg and the metal can be varied as long as the metal salt is sufficiently oil-soluble. The nature and utility of the mineral base oil and the intended use of the treated lubricating oil have an important modifying influence on the choice of metal salt.

Mixtures of metal salts of dithiocarbamic acids are also considered usable according to the invention. Such mixtures can be prepared by first preparing mixtures of dithiocarbamic acids and then converting these acidic mixtures to metal salts, or alternatively, metal salts of various dithiocarbamic acids can be prepared and then mixed to give the desired product. Thus, the mixtures that can be incorporated into the preparations according to the invention can be either the physical mixture of different metallic dithiocarbamine compounds or different dithiocarbarnate groupings bound to the same polyvalent metal atom. Examples of alkyl groups are ethyl, propyl, butyl, amyl, hexyl, octyl, decyl, dodecyl, tridecyl, pentadecyl and hexadecyl, including isomeric forms thereof. Examples of cycloalkyl groups are cyclohexyl and cycloheptyl and examples of aralkyl groups are benzyl and phenylethyl. Examples of polymethylene groups are penta- and hexamethylene groups and examples of alkyl-substituted polymethylene groups are methylpentamethylene, dimethylpentamethylene and so on.

Specific examples of metal dithiocarbamates that can be used as component (A) in the preparations according to the invention are zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc di(2-ethylhexyl)dithiocarbamate, cadmium dibutyldithiocarbamate, cadmium dioctyldithiocarbamate, cadmium octylbutyldithiocarbamate, magnesium dibutyldithiocarbamate, magnesium dioctyldithiocarbamate, cadmium dicetyldithiocarbamate, sodium diamyldithiocarbamate, sodium diisopropyldithiocarbamate etc.

The various metal salts of dithiocarbamic acids used in the preparations according to the invention are well known in this technique and can be prepared by known techniques.

Component (B) of the oil-soluble preparations according to the invention comprises at least one oil-soluble sulphurous organic compound. A wide range of sulphurised organic compounds can be used as component (B) in the preparations according to the invention and these compounds can generally be represented by the formula

where S means sulphur, x is an integer having a value from 1 to 10, and R and Ri can be the same or different organic groups. The organic groups may be hydrocarbon groups or substituted hydrocarbon groups containing alkyl, aryl, aralkyl, alkaryl, alkanoate, thiazole, imidazole, phosphorus thionate, ε-ketoalkyl and so on. The essentially hydro-

carbon groups may contain other substituents such as halogen, amino, hydroxyl, mercapto, alkoxy, aryloxy, thio, nitro, sulfonic acid, carboxylic acid, carboxylic acid ester and so on.

Specific examples of the type of sulfurized preparations that are usable as component (B) in the preparations according to the invention are aromatic, alkyl or alkenyl sulfides and polysulfides, sulfurized olefins, sulfurized carboxylic acid esters, sulfurized ester olefins, sulfurized oil and mixtures thereof. The production of such oil-soluble sulphurised preparations is described in the known technique.

The sulfurized organic compounds used according to the compound can be aromatic and alkyl sulfides such as dibenzyl sulfide, dixylyl sulfide, dicetyl sulfide, diparaffin wax sulfide and polysulfide, cracked voxoleum sulfides and so on. A method for producing the aromatic and alkyl sulphites includes the condensation of a chlorinated hydrocarbon with an organic sulphide whereby the chlorine atom from each of two molecules is displaced and the free valence from each molecule is combined into a divalent sulfur atom. Generally, the reaction is carried out in the presence of elemental sulphur.

Examples of dialkenyl sulphides which are usable in the preparations according to the invention are described in TJS-PS 2,446,072. These sulphides can be prepared by reacting an olefinic ^2-12~ hydrocarbon with elemental sulfur in the presence of zinc or a similar metal, generally in the form of an acid salt. Examples of sulfides of this type are 6,6'-dithiobis(5-methyl-4-nonene), 2-butenyl monosulfide and -disulfide, and 2-methyl-2-butenyl monosulfide and -disulfide.

The sulfurized olefins which are usable as component (B) in the preparations according to the invention include sulfurized olefins prepared by reacting an olefin, preferably a Cg_£-olefin or a low molecular weight polyolefin derived therefrom, with a sulfur-containing compound such as sulfur, sulfur monochloride and/or sulfur dichloride, hydrogen sulfide and so on.

The sulphurised organic compounds used in the preparations according to the invention can be sulphurised oils which can be produced by treating natural or synthetic oils including mineral oil, lard oil, carboxylic acid esters derived from aliphatic alcohols and fatty acids or aliphatic carboxylic acids (for example myristyl oleate and oleyl oleate) sperm whale oil and synthetic sperm whale oil substitutes and synthetic unsaturated esters or glycerides. Stable sulfurized mineral lubricating oils can be obtained by heating a suitable mineral lubricating oil with from 1 to 5% sulfur at a temperature above 175°C and preferably at 200 to 260°C for several hours to obtain a reaction product which is substantially non-corrosive against copper. The mineral lubricating oil sulfurized in this way may be distillate or residual oils obtained from paraffinic, naphthenic, or mixed base raw materials. Similarly, sulfurized fatty oils such as sulfurized lard oil may be obtained by heating lard oil with 10 to 1556 sulfur at a temperature of about 150 ° C for a period of time sufficient to give a homogeneous product.

The sulphurised fatty acid esters which can be used in the preparations according to the invention can be prepared by reacting sulphur, sulfur monochloride and/or sulfur dichloride with an unsaturated fatty ester at elevated temperatures. Typical esters are C₁₂₀ alkyl esters of C₂₋₄₄ unsaturated fatty acids such as palmitoleic, oleic, ricinol, petroselic, vaccinic, linoleic, linolenic, oleostearic, licanic acid and so on. Sulfurized fatty acid esters prepared from mixed unsaturated fatty acid esters as obtained from animal fats and vegetable oils such as tallow, linseed, olive, castor, peanut, canola, fish, sperm oil and so on can also be used. Specific examples of the fatty acid esters that can be sulfurized are lauryl thalate, methyl oleate, ethyl oleate, lauryl oleate, cetyl oleate, cetyllinoleate, lauryl ricinolate, oleolinolate, oleostearate and alkyl glycerides.

Another class of organic sulfur-containing compounds which can be used as component (B) in the preparations according to the invention are sulphurised aliphatic esters of an olefinic mono-dicarboxylic acid. For example, aliphatic C.j_30 alcohols can be used to esterify monocarboxylic acids such as acrylic acid, methacrylic acid, 2,4-pentadienoic acid and so on or fumaric, maleic, muconic acid and so on. Sulfurization of these esters is carried out with elemental sulphur, sulfur monochloride and/or sulfur dichloride.

Another class of sulphonated organic compounds which can be used in the preparations according to the invention are the diester sulphides which are characterized by the general formula

where x is from 2 to 5; y is from 1 to 6, preferably 1 to 3; and R is a C 1-6 alkyl group. The R group can be straight-chain or branched which is large enough to maintain the solubility of the preparation according to the invention in oil. Typical diesters are butyl, amyl, hexyl, heptyl, octyl, nonyl, decyl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl, lauryl and eicosyl diesters of thiodialkanoic acids such as propion -, butanoic, pentanoic and hexane acids. Of the diester sulfides, a particular example is dilauryl-3,3'-thiodipropionate.

In a preferred embodiment, the sulphurised organic compound used in the preparations according to the invention comprises sulphurised olefins. For example, organic polysulfides can be prepared by sulfochlorination of olefins containing 4 or more carbon atoms and further treatment with inorganic higher polysulfides according to US-PS 2,708,199.

In one embodiment, sulfurized olefins are prepared by (1) reacting sulfur monochloride with a stoichiometric excess of a low carbon olefin, (2) treating the resulting product with an alkali metal sulfide in the presence of free sulfur in a molar ratio of not less than 2:1 in a alcohol-water solvent, and (3) reacting this product with an inorganic base. This procedure is described in US-PS 3,471,404 and reference should be made to this when discussing the procedure for producing sulfurized olefins and in the sulfurized olefins thus produced. Generally, the olefin reactant contains from 2 to 5 carbon atoms and examples are ethylene, propylene, butylene, isobutylene, amylene and so on. In general, in the first step, sulfur monochloride is reacted with from one to two moles of olefin per moles of sulfur monochloride and the reaction is carried out by mixing the reactants at a temperature of 20 to 80° C. In the second step, the product from the first step is reacted with an alkali metal, preferably sodium sulfide, and sulphur. The mixture consists of up to 2.2 mol of metal sulphide per gram atom of sulphur, and the molar ratio of alkali metal sulphide:product from the first step is 8.0 to 1.2 mol of metal sulphide per mol step (1) product. In general, the second step is carried out in the presence of an alcohol or in an alcohol-water solvent under reflux conditions. The third step in the process is the reaction of the phosphosulfurized olefin containing from 1 to 356 chlorine with an inorganic base in an aqueous solution. Alkali metal hydroxide such as sodium hydroxide can be used. The reaction is carried out until the chlorine content is reduced to below 556 and this reaction is carried out under reflux conditions for a period of 1 to 24 hours.

The sulphurised olefins which can be used in the preparations according to the invention can also be produced by reaction under superatmospheric pressure of olefinic compounds with a mixture of sulfur and hydrogen sulphide in the presence of a catalyst, followed by the removal of low-boiling substances. This procedure for the production of sulphurised preparations which can be used is described in US-PS 4^,191,659. An eventual final step described in the patent is the removal of active sulfur with, for example, treatment with an alkali metal sulphide. The olefinic compounds which can be sulfurized by this method and used in the preparations according to the invention are of different types. They contain at least one olefinic double bond which is defined as a non-aromatic double bond, that is, one that joins two aliphatic carbon atoms. In the broadest sense, the olefin can be defined by the formula

where each of R<1>, R<2>, R<3> and R<4> is hydrogen or an organic group. In general, the R's in the above formulas which are not hydrogen can be satisfied by such groups as -C(R<5>)3, -COOR5,-CON(R<5>)2, -COON(R<5>) 4, -COOM, -CN, -X, -YR<5 >or -Ar, wherein: each R<5> is independently hydrogen, alkyl, alkenyl, aryl, substituted alkyl, substituted alkenyl or substituted aryl, provided that any any of two R<5> groups may be alkylene or substituted alkylene forming a ring of up to 12 carbon atoms;

M is one equivalent of a metal cation (preferably group I or II, eg sodium, potassium, barium, calcium);

X is halogen (eg chlorine, bromine or iodine);

Y is oxygen or divalent sulfur;

Ar is an aryl or substituted aryl group with up to approx.

12 carbon atoms.

Any two of R<1>, R<2>, R<3> and R<4> may also together form an alkylene or substituted alkylene group; for example, the olefinic compound may be alicyclic. The nature of the substituent in the substituted moieties described above is usually not critical and any such substituent is useful as long as it is or can be made compatible with the lubrication environment and does not interfere under the intended reaction conditions. Thus, substituted compounds which are so unstable that they decompose injuriously under the reaction conditions employed are not intended. However, certain substituents such as keto-

and aldehyde group undergo sulphurisation in the desired manner. The choice of suitable substituents is within the scope of the expert or can be determined by routine testing. Typical such substituents are any of those listed above as well as hydroxy, amidine, amino, sulfonyl, sulfinyl, sulfonate, nitro, phosphate, phosphite, alkali metal mercapto and the like.

The olefinic compound is usually one in which each R which is not hydrogen is independently alkyl, alkenyl or aryl, or (somewhat less commonly) a similarly substituted group. Monoolefinic and diolefinic compounds, especially the former, are preferred, and especially terminal monoolefinic hydrocarbons, that is, those compounds where R<3> and R<4> are hydrogen and R<1> and R<2> are alkyl or aryl , especially alkyl (that is, the olefin is aliphatic). Olefinic compounds having 3 to 30 and preferably from 3 to 16 (most often less than 9) carbon atoms are particularly desirable.

Isobutene, propylene and their dimers, trimers and tetramers, as well as mixtures thereof, are particularly preferred olefinic compounds. Of these compounds, isobutylene and diisobutylene are particularly desirable because of their availability and the particularly high sulfur content preparations that can be prepared therefrom.

Commercial sources of sulfur and hydrogen sulphide are usually used for the purpose of the present sulphurisation reaction and the impurities usually associated therewith may be present without adverse results. Thus, commercial diisobutene is believed to contain essentially two isomeric forms and this mixture is intended for use according to the present invention.

The amounts of sulfur and hydrogen sulphide per moles of olefinic compound are respectively 0.3-3.0 gram atoms and 0.1-1.5 moles. The preferred ranges are 0.5 to 2.0 gram atoms and 0.4 to 1.55 moles respectively. In batch operation, the reactants are introduced at levels that give these ranges. In semi-continuous and continuous operation they can be mixed in any ratio but on a mass balance basis, they are present so that they are consumed in quantities within these ratios. If, for example, the reaction vessel is initially charged with sulfur alone, olefinic compound and hydrogen sulphide are added in increments at a rate such that the desired ratio is achieved.

The temperature range in which the sulphurisation reaction is carried out is usually 50 to 350°C. The preferred range is 100 to 200°C with 125 to 180°C being particularly suitable. The reaction is carried out under superatmospheric pressure, this can be and usually is an autogenous pressure (that is the pressure naturally developed during the course of the reaction), but may also be an externally imposed pressure. The exact pressure developed during the reaction depends on such factors as the design and operation of the system, reaction temperature and vapor pressure of the reactants and products and may vary during the reaction.

It is often advantageous to incorporate substances which can be used as sulphurisation catalysts in the reaction mixture. These substances can be acidic, basic or neutral. Useful neutral or acidic substances include acidified clays such as "Super Filtrol", p-toluenesulfonic acid, dialkylphosphorodithio acids and phosphorus sulfides such as phosphorus pentasulfide.

The preferred catalysts are basic substances. These can be inorganic oxides and salts such as sodium hydroxide, calcium oxide and sodium sulphide. However, the most desirable basic catalysts are nitrogen bases including ammonia and amines. The amines include primary, secondary and tertiary hydrocarbylamines where the hydrocarbyl residues are alkyl, aryl, aralkyl, alkaryl or the like and contain 1-20 carbon atoms. Suitable amines are aniline, benzylamine, dibenzylamine, dodecylamine, naphthylamine, tallamines, N-ethyldipropylamine, N-phenylbenzylamine, N,N-diethylbutylamine, m-toluidine and 2,3-xylidine. Also useful are heterocyclic amines such as pyrrolidine, N-methylpyrrolidine, piperidine, pyridine and quinoline.

The preferred basic catalysts are ammonia and primary, secondary or tertiary alkylamines with 1-8 carbon atoms in the alkyl residues. Representative amines of this type are methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, di-n-butylamine, tri-n-butylamine, tri-sec-hexylamine and tri-n-octylamine. Mixtures of these amines can be used as well as mixtures of ammonia and amines.

The amount of catalytic material used is generally 0.05-2.0% by weight of the olefinic compound. In the case of the preferred ammonia and amine catalysts, 0.0005-0.5 mol per mol olefin preferred and 0.001-0.1 mol particularly desirable.

Furthermore, water can also be present in the reaction mixture, either as a catalyst or as a diluent for one or more of the above-named catalysts. The amount of water shown to be present is usually 1-25 wt-56 of the olefinic compound. However, the presence of water is not essential and when certain types of reaction equipment are used it may be advantageous to carry out the reaction under essentially water-free conditions.

The method is usually carried out in the absence of solvents and diluents other than water. However, it may sometimes be desirable to use a substantially inert, usually liquid organic diluent in the reaction. The nature of suitable diluents will be apparent to those skilled in the art. The time required for the reaction to be completed will vary depending on reagents, the ratio between them, reaction temperature, presence or absence of catalyst, reagent purity and so on.

The course of the reaction is conveniently followed by monitoring the pressure in the reaction vessel; the reaction can be considered finished when the pressure equalizes to a constant value.

After the preparation of the sulfurized mixture by the procedure described above, essentially all low-boiling substances are removed. The nature of these low-boiling substances varies according to the amount and type of reactants used and the reaction conditions. It will also vary to a certain extent depending on the use for which the sulphurised products are intended, as well as factors such as odor and flammability considerations, recycling needs for reactants and by-products and the like. In most cases, the product should have a flash point above 30°C, preferably 70°C and preferably above 120°C, as determined by ASTM Procedure D93. Reference should also be made to ASTM Procedure D56 and D1310.

In addition to the starting materials such as the olefinic compound, the low-boiling materials will often include mercaptans and monosulfides, especially when the starting olefin contains less than 9 carbon atoms, and under these circumstances it is preferred that the product not contain more than 5 wt-# of such starting materials, with mercaptans and monosulphides. If these materials are gaseous at ambient temperature and

-pressure, they can be easily removed by venting the reaction vessel, and they can be recycled if desired. If less volatile starting materials are present it may be

necessary to resort to techniques such as distillation at atmospheric pressure or vacuum distillation or stripping. Other useful methods are passing an inert gas such as nitrogen through the mixture at a suitable temperature and a suitable pressure. Large-scale gas chromatography and molecular distillation can also be used.

Any solids present in the reaction mixture can be conveniently removed, in most cases by simply pouring off the liquid product. If further removal of solids is desired, conventional techniques such as filtration or centrifugation can be used.

A further possible step in the method of the invention is treatment of the sulphurised product, obtained as described above, to reduce active sulphur. By "active sulphur" is meant sulfur in a form that can cause stress on copper and similar materials. When active sulfur is to be reduced, any of several known methods in this technique can be used, an illustrative method is treatment with an alkali metal sulphite as described in US-PS 3,498,915.

Other possible treatments can be applied to improve such properties as smell, color and staining properties of the sulphurised compounds. These may include treatment with acid clays such as superfiltrol and filtration through Fuller's earth, activated carbon, alumina clays and the like. Such treatments are often not necessary when a basic catalyst is used.

The exact chemical nature of the sulphuretted preparations which are prepared in this way is not known with certainty, and it is most convenient to describe them in terms of their method of manufacture. It appears, however, that when prepared from olefins containing less than 9 and especially less than 7 carbon atoms, they principally comprise disulfides, trisulfides and tetrasulfides. The sulfur content of these sulphurised preparations is usually from 2-60 weight-56, preferably 25-60 and most preferably from 40-5056.

The method for producing the sulfurized olefins in this way is illustrated by the following examples. Unless otherwise stated, in these and other examples and in other parts of the description and claims, all parts and percentages are by weight.

Example I

Sulfur (526 parts, 16.4 mol) is charged to a jacketed high-pressure reactor which is equipped with agitators and internal cooling coils. Coolant brine is circulated through the windings to cool the reactor prior to introduction of gaseous reactants. After sealing the reactor, evacuation to approx. 2 torr and cooling, 920 parts corresponding to 16.4 mol isobutene and 279 parts corresponding to 8.2 mol hydrogen sulphide are charged to the reactor. The reactor is heated by using steam in the outer jacket to a temperature of approx. 182°C for approx. 1.5 hours. A maximum pressure of 9.308*1O3 kPa is achieved at approx. 168° C during this heating. Before reaching the peak reaction temperature, the pressure begins to drop and continues to drop steadily as gaseous reactants are consumed. After approx. 10 hours at a reaction temperature of approx. 182 °C, the pressure is 2.137-IO<3> to 2.344'IO<3> kPa and the rate of pressure change is approx. 34,475'10<3> to 68.95-10<3> Pa per hour. Unreacted hydrogen sulphide and isobutene are vented to a recovery system. After the pressure in the reactor has dropped to atmospheric, the sulfurized mixture is recovered as a liquid.

The mixture is blown with nitrogen at approx. 100°C to remove low-boiling substances including unreacted isobutene, mercaptans and monosulphides. The residue after nitrogen blowing is stirred with 556 "Super Filtrol" and filtered, using a diatomaceous earth filter aid. The filtrate is the desired sulphurised preparation containing 42.556 sulphur.

Example II

151 parts of sulfur are charged to a reactor similar to that in example I. The sulfur is heated to 160°C and the reactor is sealed and evacuated. 72 parts of hydrogen sulphide are added slowly to the reactor during approx. 4.5 hours. Then 1.6 parts of the catalyst n-butylamine are added to the reactor after approx. 3.8 parts of hydrogen sulphide have been added. 157 parts isobutylene is added slowly to the reactor containing sulphur, catalyst and approx. 10 divide hydrogen sulphide in such a way that the rate of addition of isobutylene and hydrogen sulphide is such that a 1056 molar excess of hydrogen sulphide is maintained until all the hydrogen sulphide has been added. The addition of the rest of the isobutylene is continued until all 157 parts have been added. The temperature is kept within the range of 160-171 °C during the preceding addition and reaction with occasional cooling if necessary. The reaction mixture is kept at 171°C for 5 hours, after which unreacted hydrogen sulphide and isobutylene are vented to a recovery system until the pressure in the container is reduced to atmospheric. Separation of low-boiling substances from the reaction raw products is carried out by nitrogen blowing and then vacuum stripping. The rest is then filtered. The filtrate is then the desired sulphurised preparation containing 47 wt-56 sulphur.

In another preferred embodiment, the sulfurized organic compound, component (B), is derived from a special type of cyclic or bicyclic olefin which is a Diels-Alder adduct of at least one dienophile with at least one aliphatic conjugated diene. The sulphurised Diels-Alder adducts can be prepared by reacting various sulphurising agents with the Diels-Alder adducts as described in more detail below. Preferably, the sulfurizing agent is sulfur. The Diels-Alder adducts are a well-known class of compounds produced by the diene synthesis or Diels-Alder reaction. A summary of the prior art relating to this class of compounds can be found in the Russian monograph "Dienovyi Sintes", Izdatelstwo Akademii Nauk SSSR. 1963 by A.S. Onischenko. (Translated into English by L. Mandel as A.S. Onischenko, "Diene Synthesis", N.Y. , Daniel Davey and Co., Inc., 1964).

In principle, the diene synthesis or the Diels-Alder reaction involves the reaction of at least one conjugated diene, >C=C-C=C<, with at least one ethylenic or acetylenically unsaturated compound,

>C=C< or -C=C-, these latter compounds are known as dienophiles. The reaction can be represented as follows:

The products A and B are generally called Diels-Alder adducts. It is these adducts that are used as starting materials for the production of the sulphurised Diels-Alder adducts that are used according to the invention.

Representative examples of the 1,3-dienes are aliphatic and alicyclic conjugated diolefins or dienes of the formula where R to R<5> are each independently selected from halogen, alkyl, alkoxy, alkenyl, alkenyloxy, carboxy, cyano, amino, alkylamino, dialkylamino, phenyl and phenyl which is substituted with 1 to 3 substituents corresponding to R to R<5> provided that a pair of R's next to each other carbon atoms do not form an additional double bond in the diene, or R, R<2>, R<3 > and R<5> are as defined and R<*> and R<4> are alkylene groups connected to form a ring together with the nitrogen atom. Preferably, no more than three of the R variables are different from hydrogen and at least one is hydrogen. Usually, the total number of carbon atoms in the diene will not exceed 20. In a preferred feature of the invention, adducts are used where both R<2> and R<3> are hydrogen and at least one of the remaining R variables is also hydrogen. Preferably, the carbon content of these R variables when different from hydrogen is 7 or less. In the most preferred class, those dienes in which R, R<1>, R<4> and R<5> are hydrogen, chlorine or lower alkyl are particularly useful. Specific examples of R variables are the following groups: methyl, ethyl, phenyl, H00C-, N=C-, CH3O-. CH3COO-, CH3CH20-, CH3C(0)-, HC(0)-, Cl, Br, tert-butyl, CF3, tolyl and so on. Piperylene, isoprene, methyl isoprene, chloroprene and 1,3 butadiene are among the preferred dienes for use in the preparation of the Diels-Alder adducts.

In addition to these linear 1,3-conjugated dienes, cyclic dienes are also useful as reactants in the formation of Diels-Alder adducts. Examples of these cyclic dienes are cyclopentadienes, fulvenes, 1,3-cyclohexadienes, 1,3-cycloheptadienes, 1,3,5-cycloheptatrienes, cyclooctatetraene and 1,3,5-cyclononatrienes. Various substituted derivatives of these compounds enter the diene synthesis.

The dienophiles suitable for reaction with the above-mentioned dienes to form adducts used as reactants can be represented by the formula

where the K variables are the same as the R variables in formula IV above provided that a pair of K's can form a further carbon-carbon bond, that is K-CEC-Kg, but does not necessarily do this.

A preferred class of dienophiles are those in which at least one of the K variables is selected from electron-accepting groups such as formyl, cyano, nitro, carboxy, carbohydrocarbyloxy, hydrocarbylcarbonyl, hydrocarbylsulfonyl, carbamyl, acrylcarbamyl, N-acyl-N-hydrocarbylcarbamyl, N-hydrocarbylcarbamyl and NfN, -dihydrocarbylcarbamyl. These K variables which are non-electron accepting groups are hydrogen, hydrocarbyl or substituted hydrocarbyl groups. Generally, hydrocarbyl and substituted hydrocarbyl groups will not contain more than 10 carbon atoms each.

The hydrocarbyl groups present as N-hydrocarbyl substituents are preferably alkyl of 1 to 30 carbon atoms and especially 1 to 10 carbon atoms. Representative of this class of dienophiles are the following: nitroalkenes, for example 1-nitrobutene-1, 1-nitropene-1, 3-methyl-1-nitrobutene-1, 1-nitroheptene-1, 1-nitrooctene-1, 4-ethoxy -1-nitrobutene-1; cx-, e-ethylenically unsaturated aliphatic carboxylic acid esters, for example alkyl acrylates and a-methyl alkyl acrylates (that is, alkyl methacrylates) such as butyl acrylate and butyl methacrylate, decyl acrylate and decyl methacrylate, di-(n-butyl) maleate, di-(t-butyl maleate) ); acrylonitrile, methacrylonitrile, e-nitrostyrene, methyl vinyl sulfone, acrolein, acrylic acid; α-, 3-ethylenically unsaturated aliphatic carboxylic acid amides, for example acrylamide, N,N-dibutylacrylamide, methacrylamide, N-dodecyl methacrylamide, N-pentylcrotonamide; crotonaldehyde, crotonic acid, <p>,3-dimethyldivinylketone, methylvinylketone, N-vinylpyrrolidone, alkenyl halides and the like.

A preferred class of dienophiles are those in which at least one but not more than two K variables are -C(0)0-Ro where RQ is the residue of a saturated aliphatic alcohol of up to 40 carbon atoms; for example at least one K is carbohydrocarbyloxy such as carboethoxy, carbobutoxy and so on, the aliphatic alcohol from which —RQ is derived may be a mono- or polyhydroalcohol such as alkylene glycols, alkanols, aminoalkanols, alkoxy-substituted alkanols, ethanol, ethoxyethanolpropanol, <p>— diethyl aminoethanol, dodecyl alcohol, diethylene glycol, tripropylene glycol, tetrabutylene glycol, hexanol, octanol, isooctyl alcohol and the like. In this particularly preferred class of dienophiles, no more than two K-variables will be -C(0)-0-Ro groups and the remaining K-variables will be hydrogen or lower alkyl, for example methyl, ethyl, propyl, isopropyl and the like.

Specific examples of dienophiles of the type discussed above are those in which at least one of the K variables is one of the following groups: hydrogen, methyl, ethyl, phenyl, E00C-, HC(0)-, CH2=CH-, HC =C-, CH3C(0)0-, C1CH2-, HOCHg-, a-<py>ridy1,

-NO2, Cl, Br, propyl, iso-butyl and so on.

In addition to the ethylenically unsaturated dienophiles, there are many usable acetylenically unsaturated dienophiles, for example propiolaldehyde, methylethynyl ketone, propylethynyl ketone, propenylethynyl ketone, propiolic acid, propiolic acid nitrile, ethyl propiolate, tetrolic acid, propargyl aldehyde, acetylenic dicarboxylic acid, dimethyl esters of acetylenic dicarboxylic acid, dibenzoylacetylene and the like.

Cyclic dienophiles include cyclopentenedione, coumarin, 3-cyanocoumarin, dimethylmaleic anhydride, 3,6-endomethylene-cyclohexenedicarboxylic acid and so on. With the exception of the unsaturated dicarboxylic anhydrides derived from linear dicarboxylic acids (e.g., maleic anhydride, methyl-maleic anhydride, chloromaleic anhydride), this class of cyclic dienophiles is limited in commercial utility due to its limited availability and other economic considerations.

The reaction products of these dienes and dienophiles correspond to the general formula

where R to R<5> and K to K3 are as indicated above. If the dienoparts entering the reaction are acetylenic rather than ethylenic, two of the K variables, one from each carbon atom, form an additional carbon-carbon double bond. Where the diene and/or dienophile is itself cyclic, the adduct will obviously become bicyclic, tricyclic, fused, and so on, as exemplified below:

Typically, the adducts involve the reaction of equimolecular amounts of diene and dienophile. If, however, the dienophile has more than one ethylenic bond, it is possible that additional diene may react if present in the reaction mixture.

The adducts and the methods for producing the adducts shall be exemplified by the following examples.

EXAMPLE A

A mixture comprising 400 parts toluene and 66.7 parts aluminum chloride is charged to a two-liter flask equipped with a stirrer, nitrogen inlet tube, and a solid carbon dioxide-cooled reflux condenser. A second mixture comprising 640 parts or 5 moles of butyl acrylate and 240.8 parts of toluene is added to the AICI 3 slurry while maintaining the temperature within the range of 37-58°C over a 0.25 hour period. Then 31 parts corresponding to 5.8 moles of butadiene are added to the slurry over a 2.75-hour period while maintaining the temperature in the reaction mass at 50-61°C by means of external cooling. The reaction mass is blown with nitrogen for approx. 0.33 hours and then transferred to a four-liter separatory funnel and washed with a solution of 150 parts concentrated hydrochloric acid in 1100 parts water. The product is then subjected to two additional water washes using 1,000 parts of water per washing. The washed reaction product is then distilled to remove unreacted butyl acrylate and toluene. The residue from this first distillation step is subjected to further distillation at a pressure of 9-10 mm Hg, after which 758 parts of the desired product are collected over the temperature range 105 to 115°C.

EXAMPLE B

The adduct of isoprene and acrylonitrile is prepared by mixing 136 parts of isoprene, 106 parts of acrylonitrile and 0.5 parts of hydroquinone (polymerization inhibitor) in a cradle autoclave and then heating the whole for 16 hours to a temperature in the range of 130-140°C. The autoclave is vented and the contents decanted, giving 240 parts of a pale yellow liquid. This liquid is stripped at a temperature of 90° C. and a pressure of 100 mm Hg, which gives the desired liquid product as a residue.

EXAMPLE C

Using the procedure in Example B, 136 parts isoprene, 172 parts methyl acrylate and 0.9 parts hydroquinone are converted to isoprene methyl acrylate adduct.

EXAMPLE D

Following the procedure of Example B, 104 parts liquefied butadiene, 166 parts methyl acrylate and 1 part hydroquinone are charged to the cradle auto furnace and heated to 130-135°C for 14 hours. The product is then decanted and stripped and 237 parts of adduct are obtained.

EXAMPLE E

The adduct of isoprene and methyl methacrylate is prepared by reacting 745 parts of isoprene with 1095 parts of methyl methacrylate in the presence of 5.4 parts of hydroquinone in a cradle autoclave followed by the procedure in Example B above. 1490 parts of adduct are obtained.

EXAMPLE F

810 parts adduct of butadiene and dlbutyl maleate is prepared by reacting 915 parts dlbutyl maleate, 216 parts liquefied butadiene and 3.4 parts hydroquinone in the cradle car oven according to example B.

EXAMPLE G

A reaction mixture comprising 378 parts of butadiene, 778 parts of N-vinylpyrrolidone and 3.5 parts of hydroquinone is added to a cradle autoclave pre-cooled to -35°C. The autoclave is then heated to a temperature of 130-140°C for approx. 15 hours. After aeration, decantation and stripping of the reaction mass, 75 parts of the desired adduct are obtained.

EXAMPLE H

Following the technique of Example B, 270 liquefied butadiene, 1060 parts of isodecyl acrylate and 4 parts of hydroquinone are reacted in the cradle autoclave at a temperature of 130-140°C for approx. 11 hours. After decantation and stripping, 1136 parts of adduct are recovered.

EXAMPLE I

Following the same general procedure as in Example A, 132 parts or 2 moles of cyclopentadlene, 256 or 2 moles of butyl acrylate and 12.8 parts of aluminum chloride are reacted to produce the desired adduct. The butyl acrylate and aluminum chloride are first added to a two-liter flask equipped with a stirrer and reflux condenser. While heating the reaction mass to a temperature within the range of 59-52°C. cyclopentadlene is added to the flask over the course of half an hour. The reaction mass is then heated for approx. 7.5 hours at a temperature of 95-100°C. The product is washed with a solution containing 400 parts water and 100 parts concentrated hydrochloric acid and the aqueous layer is discarded. Then 1500 parts of benzene are added to the reaction mass and the benzene solution is washed with 300 parts of water and the aqueous phase is removed. The benzene is removed by distillation and the residue is stripped at 0.2 mm hg to recover the adduct as distillate.

EXAMPLE J

Following the technique of Example B, the adduct of butadiene and allyl chloride is prepared using two moles of each reactant.

EXAMPLE K

139 parts or 1 mol of adduct of butadiene and methyl acrylate is transesterified with 158 parts or 1 mol of decyl alcohol. The reactants are added to a reaction flask and 3 parts sodium methoxide are added. The reaction mixture is then heated to a temperature of 190-200°C over a period of 7 hours. The reaction mass is washed with a 1096 sodium hydroxide solution and then 250 parts of naphtha are added. The naphtha solution is washed with water. After complete washing, 150 parts of toluene are added and the reaction mass is stripped to 150<*>C under a pressure of 28 mm hg. A dark brown liquid product in an amount of 225 parts is recovered. This product is fractionated under reduced pressure, resulting in the recovery of 178 parts of the product boiling in the range of 130-133°C at a pressure of 0.45 to 0.6 parts Hg.

EXAMPLE L

The general procedure in Example A is repeated except that only 270 parts or 5 moles of butadiene are incorporated into the reaction mixture. The sulfur-containing compounds are easily prepared by heating a mixture of a sulfurizing agent such as sulfur and at least one of the Diels-Alder adducts of the type described above at a temperature in the range of 110°C to just below the decomposition temperature of the Diels-Alder adducts. Temperatures in the range of 110 to 200°C will usually be used. These reactions result in a mixture of products, some of which have been identified. In the compound of known structure, the sulfur reacts with the substituted unsaturated cycloaliphatic reactants on a double bond in the nucleus of the unsaturated reactant.

The molar ratio between sulfur and Diels-Alder adduct used in the preparation of the sulfur-containing preparation is from 0.5:1 to 10:1, although the molar ratio will generally be less than 4:1. In one embodiment of the invention, the molar ratio is less than 1.7:1 and most preferably less than 1:1.

The sulfurization reaction can be carried out in the presence of suitable inert organic solvents such as mineral oils, C, 1O<->alkanes and so on, although solvent is not generally required. After the reaction is complete, the reaction mass can be filtered and/or subjected to other conventional cleaning techniques. There is no need to separate the different sulfur-containing products as these can be used in the form of a reaction mixture comprising compounds of known and unknown structure.

As hydrogen sulphide is an unwanted pollutant, it is advantageous to use standard procedures to support the removal of HgS from the products. Blowing with steam, alcohols, air or nitrogen gas supports the removal of HgS in the same way as heating under reduced pressure with or without blowing.

It is sometimes advantageous to incorporate substances that can be used as sulphurisation catalysts in the reaction mixture. These substances can be acidic, basic or neutral. Useful neutral and basic substances are acidified clays such as "Super Filtrol", p-toluenesulfonic acid, dialkyl phosphorodithionic acids, phosphorus sulfides such as phosphorus pentasulfide and phosphites such as triaryl phosphites (eg triphenyl phosphite).

The basic substances can be inorganic oxides and salts such as sodium hydroxide, calcium oxide and sodium sulphide. However, the most desirable basic catalysts are nitrogen bases including ammonia and amines. The amines include primary, secondary and tertiary hydrocarbylamines in which the hydrocarbyl residues are alkyl, aryl, aralkyl, alkaryl or the like and contain 1-20 carbon atoms. Suitable amines are aniline, benzylamine, dibenzylamine, dodecylamine, naphthylamine, tallow amines, N-ethyldipropylamine, N-phenylbenzylamine, N,N-diethylbutylamine, m-toluidine and 2,3-xylidine. Also useful are heterocyclic amines such as pyrrolidine, N-methylpyrrolidine, piperidine, pyridine and quinoline.

The preferred basic catalysts are ammonia and primary, secondary or tertiary alkylamines with 1-8 carbon atoms in the alkyl residues. Representative amines of this type are methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, di-n-butylamine, tri-n-butylamine, tri-sec-hexylamine and tri-n-octylamine. Mixtures of these amines can be used in the same way as mixtures of ammonia and amines. When a catalyst is used, the amount is generally approx. 0.05-2.0 wt-56 of the adduct.

The following examples shall illustrate the preparation of the sulfur-containing compounds derived from the Diels-Alder adducts.

EXAMPLE III

To 225 parts or 1.65 mol of isoprene methacrylate adduct from example C, heated to a temperature of 110-120°C, 53 parts or 1.65 mol of sulfur flower are added during 45 minutes. The heating is continued for 4.5 hours at a temperature within the range of 130 to 160°C. After cooling to room temperature, the reaction mixture is filtered through a medium sintered glass funnel. The filtrate consists of 301 parts of the desired sulfur-containing products.

EXAMPLE IV

A reaction mixture comprising 1175 parts or 6 moles of Diels-Alder adduct of butyl acrylate and isoprene and 192 parts or 6 moles of sulfur flower is heated for 0.5 hours at 108-110°C and then to 155-165°C for 6 hours with simultaneous bubbling of nitrogen gas through the reaction mixture in an amount of 0.007 to 0.014 standard m<5> per hour. At the end of the heating period, the reaction mixture is allowed to cool and filtered at room temperature. Then the product is allowed to stand for 24 hours and the ref Utreres. The filtrate is the desired product.

EXAMPLE V

4.5 mol of sulfur and 4.5 mol of the adduct isoprene-methyl methacrylate are mixed at room temperature and heated for 1 hour to 110° C while blowing nitrogen through the reaction mass in an amount of 0.007-0.014 standard m<5> per hour. The temperature of the reaction mixture is then raised to 150-155°C for 6 hours while maintaining the nitrogen blowing. After heating, the reaction mixture is set aside and allowed to cool to room temperature for a few hours, after which filtration is carried out. The filtrate consists of 842 parts of the desired sulfur-containing product.

EXAMPLE VI

A one liter flask equipped with a stirrer, reflux condenser, condenser and nitrogen inlet pipe is charged with 256 parts or 1 mole of the adduct of butadiene and isodecyl acrylate and 51 g corresponding to 1.6 moles of sulfur and then heated for 12 hours to a temperature, placed in 21 hours and filtered at room temperature, whereby the desired product is obtained as the filtrate.

EXAMPLE VII

A mixture of 1703 parts or 9.4 moles of a butyl acrylate-butadiene adduct as prepared in Example L, 280 parts or 8.8 moles of sulfur and 17 parts of triphenyl phosphite is prepared in a reaction vessel and gradually heated over 2 hours to a temperature of about. 185°C while stirring and blowing with nitrogen. The reaction mixture is exothermic near 160-170°C and the mixture is kept at approx. 185°C for 3 hours. The mixture is cooled to 90°C within 2 hours and filtered using a filter aid. The filtrate is the desired product containing 14.056 sulfur.

EXAMPLE VIII

The procedure of Example 7 is repeated except that the triphenyl phosphite is omitted from the reaction mixture.

EXAMPLE IX

The procedure according to Example VII is repeated except that triphenylphosphite is replaced with 2.0 parts of triamylamine as sulphurisation catalyst.

EXAMPLE X

A mixture of 547 parts of a butyl acrylate-butadiene adduct prepared as in example L and 5.5 parts of triphenyl phosphite is prepared in a reaction vessel and heated with stirring to a temperature of approx. 50"C, after which 94 parts of sulfur are added over the course of 30 minutes. The mixture is heated to 150°C for 3 hours while being flushed with nitrogen. The mixture is then heated to approx. 185°C over the course of approx. 1 hour. The reaction is exothermic and the temperature is maintained at about 185°C using a cold water jacket for about 5 hours. At this point the contents of the reaction vessel are cooled to 85°C and 33 parts of mineral oil are added. The mixture is filtered at this temperature and the filtrate is the desired product where sulfur :adduct ratio is 0.98:1.

EXAMPLE XI

The general procedure of Example X is carried out except that triphenyl phosphite is not included in the reaction mixture.

EXAMPLE XII

A mixture of 500 parts or 2.7 mol of a butyl acrylate-butadiene adduct prepared as in Example L and 109 parts or 3.43 mol of sulphur, is prepared and heated to 180°C and held at a temperature of 180-190°C for approx. .6.5 hours. The mixture is cooled under a nitrogen gas purge to remove hydrogen sulfide odor. The reaction mixture is filtered and the filtrate is the desired product containing 15.856 sulfur.

EXAMPLE XIII

A mixture of 728 parts or 4.0 moles of a butyl acrylate-butadiene adduct prepared as in Example L, 218 parts or 6.8 moles of sulfur and 7 parts of triphenyl phosphite is prepared and heated with stirring to a temperature of about 181°C in 1.3 hours. The mixture is kept under nitrogen purging at a temperature of 181-187°C for 3 hours. After the material has cooled to approx. 85°C during 1.4 hours, the mixture is filtered using a filter aid and the filtrate is the desired product containing 23.196 sulfur.

EXAMPLE XIV

A mixture of 910 parts or 5 moles of a butyl acrylate-butadiene adduct prepared as in Example L, 208 parts or 6.5 moles of sulfur and 9 parts of triphenyl phosphite, is prepared and heated with stirring and nitrogen blowing to a temperature of approx. 140°C for 1.3 hours. Heating is continued to raise the temperature to 187°C over 1.5 hours, and the material is held at 183-187°C for 3.2 hours. After cooling the mixture to 89°C, it is filtered with a filter aid and the filtrate is the desired product containing 18.256 sulfur.

EXAMPLE XV

A mixture of 910 parts or 5 moles of a butyl acrylate-butadiene adduct prepared as in Example L, 128 parts or 4 moles of sulfur and 9 parts of triphenyl phosphite is prepared and heated with stirring while purging with nitrogen to a temperature of 142°C for about. 1 hour. The heating is continued to raise the temperature to 185-186°C during approx. 2 hours and the mixture is kept at 185-187°C for 3.2 hours. After the reaction mixture has cooled to 96°C, it is filtered with a filter aid and the filtrate is the desired product containing 12.0 sulphur.

EXAMPLE XVI

The general procedure of Example XV is repeated except that the mixture contains 259 parts or 8.09 moles of sulfur. The product obtained in this way contains 21.756 sulfur.

EXAMPLE XVII

A reaction mixture comprising 1175 grams or 6 moles of Diels-Alder adduct of butyl acrylate and isoprene and 384 grams or 12 moles of sulfur dioxide is heated for half an hour at 1.08-110"C and then to 155-165"C for 6 hours with bubbling of nitrogen gas through the reaction mixture in an amount of 0.007 to 0.014 standard m<5> per hour. At the end of the heating, the reaction mixture is allowed to cool and filter at room temperature. The product is then left for 24 hours and filtered again. The filtrate with a weight of 1278 g is the desired product.

EXAMPLES XVIII-XXII

Examples XVIII to XXII illustrate the preparation of other sulfur-containing compounds which can be used according to the invention. In each case, the adduct and sulfur are mixed in a reaction flask and then heated to a temperature in the range of 150-160°C for a period of 7 to 10 hours while bubbling nitrogen through the reaction mixture. The sulfurized products are then allowed to cool to room temperature and allowed to stand. for several hours.The reaction mass is then filtered, the filtrate forming the desired sulphur-containing products.

It has been found that, if these sulfur-containing products are treated with an aqueous solution of sodium sulfide containing from 5 to 75 wt.-56 Na 2 S, the treated product may show less tendency to darken freshly polished copper metal.

The treatment involves mixing sulphurised reaction product and sodium sulphide solution for a period of time sufficient for all unreacted sulfur to be captured, usually a period of a few minutes to several hours, depending on the amount of unreacted sulphur, amount and concentration of sodium sulphide solution. The temperature is not critical, but will usually lie within the range of 20 to 100°C. After the treatment, the resulting aqueous phase is separated from the organic phase by conventional techniques, for example decantation and so on. Other alkali metal sulphides, M2sx where M is an alkali metal and x is 1, 2 or 3, can be used to capture unreacted sulphur, but those where c is greater than 1 are not nearly as effective. Sodium sulfide solutions are preferred because of economy and efficiency. This procedure is described in greater detail in US-PS 3,498,915.

It has also been determined that treating the reaction products with solid, insoluble acids such as acid clays or acid resins and then filtering the sulfurized reaction mass improves the product in terms of color and solubility characteristics. Such treatment comprises thorough mixing of the reaction mixture with from 0.1 to 10 wt-56 of solid acidic material at a temperature of 25-150°C with subsequent filtration of the product.

As previously mentioned, there is no need to separate the sulfur-containing products produced by the above-mentioned reactions. The reaction product is a mixture which includes compounds whose structure is confirmed but which also includes compounds whose structure is not known. Because it is not economically feasible to separate the components in the reaction mixture, they are used in combination as a mixture of sulfur-containing compounds.

In order to remove the last traces of impurities from the reaction mixture, especially when the adduct used was prepared using a Lewis acid catalyst, for example AICI3, it is sometimes desirable to add an organic inert solvent to the liquid reaction product, and, after thorough mixing , to refilter the material. The solvent is then stripped from the product. Suitable solvents are solvents of the type mentioned above, for example benzene, toluene and higher alkanes and so on. A particularly useful class of solvents is textile spirits.

In addition, other conventional cleaning techniques can be advantageously used for cleaning sulphurised products which are used according to the invention. For example, commercial filter aids can be added to the material prior to filtration to increase the efficiency of the filtration. Filtration through diatomaceous earth is particularly useful where the aim is to remove essentially all solids. However, this is well known to those skilled in the art and requires no special description.

The sulphurised preparation used according to the invention (component B) can be at least one sulphurised terpene compound or a preparation prepared by sulphurisation of a mixture comprising at least one terpene and at least one other olefinic compound.

The term "terpene compound" as used here in the description of claims is intended to include the various isomeric terpene hydrocarbons with empirical formula Cio^it, such as the compound found in turpentine, pine needle oil and dipentenes, and various synthetic and naturally occurring oxygenated derivatives.

Mixtures of these different compounds will generally be used, especially when natural products such as pine needle oil and turpentine are used. Pine oil is obtained, for example, by destructive distillation of waste pine wood with superheated steam and comprises a mixture of terpene derivatives such as a-terpineol, e-terpineol, a-fencol. camphor, borneol/isoborneol, fencone, estragole, dihydro oc-terpineol, anethole and other mono-terpene hydrocarbons. The specific ratios and quantities of the various components in a given oil will depend on the particular source and degree of purity. A group of pine needle oil derived products are commercially available from Hercules Incorporated. Furnace oil products generally known as terpene alcohols, available from Hercules Incorporated, have been found to be particularly useful in the preparation of the sulfurized products used in accordance with the invention. Examples of such products are a-Terpineol containing 95-9756 a-Terpineol, a highly pure tertiary terpene alcohol mixture which characteristically contains 96.356 tertiary alcohols; Terpineol 318 Prime which is a mixture of isomeric terpeniols obtained by dehydration of terpene hydrate and contains 60-65 weight-56 a-terpeniol and 15-2056 p<->terpeniol, as well as 18-2056 other tertiary terpene alcohols. Other blends and grades of usable pine needle oil products are also available from Hercules under the designations "Yarmor 302", "Herco pine oil", "Yarmor 302W", "Yarmor F" and "Yarmor 60".

The terpene compounds which can be used in the preparations according to the invention can be sulphurised terpene compounds, sulphurised mixtures of terpene compounds or mixtures of at least one terpene compound and at least one sulphurised terpene compound. Sulfurized terpene compounds can be produced by sulphurizing terpene compounds with sulphur, sulfur halides or mixtures of sulfur or sulfur dioxide with hydrogen sulphide as will be described in more detail below. Furthermore, sulfurization of various terpene compounds is described in the known technique, thus sulfurization of pine needle oil is described in US-PS 2,012,446.

The other olefinic compounds which may be combined with the terpene compound may be any of several olefinic compounds such as those previously described. For example, the olefins may be of the type illustrated in formula IV above.

The second olefin used in combination with the terpene can also be an unsaturated fatty acid, an unsaturated fatty acid ester, mixtures thereof or mixtures thereof with the olefins as described above. The term "fatty acid" as used here refers to acids which can be obtained by hydrolysis of naturally occurring vegetable or animal fats or oils. These fatty acids usually contain 16 to 20 carbon atoms and are mixtures of saturated and unsaturated fatty acids. The unsaturated fatty acids usually contained in the naturally occurring vegetable or animal fats and oils may contain one or more double bonds and such acids include palmitoleic acid, oleic acid, linoleic acid, linoleic acid and erucic acid.

The unsaturated fatty acids may include mixtures of acids such as those obtained from naturally occurring animal and vegetable oils such as tallow oil, tallow oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil or wheat germ oil. Tall oil is a mixture of rosin acids, mainly abietic acid, and unsaturated fatty acids, mainly oleic and linoleic acids. Tall oil is a by-product of the sulphate process for the production of wood pulp.

The most particularly preferred unsaturated fatty acid esters are fatty oils, i.e. naturally occurring esters of glycerol with fatty acids as described above, and synthetic esters of similar structure. Examples of naturally occurring unsaturated fats and oils containing them are animal fats such as Neaf's vegetable oil, lard oil, depot fat, beef tallow and so on. Examples of naturally occurring vegetable oils are cottonseed oil, corn oil, poppy seed oil, saffron oil, sesame oil, soya oil, sunflower seed oil and wheat germ oil. The fatty acid esters which are usable can also be prepared from aliphatic olefinic acids of the type described above such as oleic acid, linoleic acid, linolenic acid and behenic acid by reaction with alcohols and polyols. Examples of aliphatic alcohols which can be reacted with the above-mentioned acids are monohydroxy alcohols such as methanol, ethanol, n-propanol, isopropanol, butanols and so on; and polyhydroxy alcohols such as ethylene glycol, propylene glycol, trimethylene glycol, propylene glycol, trimethylene glycol, neopentyl glycol, glycerol and so on.

The second olefinic compound which is used together with the terpene compound in the preparation of the preparations according to the invention comprises sulphurised derivatives of said olefinic compounds. Thus, the olefin may be one or more of any of the above-mentioned olefinic compounds, their sulphurised derivatives or mixtures of said olefinic compounds and sulphurised derivatives. The sulphurised derivatives can be prepared by methods which are known per se by using sulphurisation reagents such as sulphur, sulfur halides or mixtures of sulfur or sulfur dioxide with hydrogen sulphide.

The amount of terpene compounds and other olefinic compounds contained in the mixture to be sulfurized can vary over a wide spectrum although a sufficient amount of the other olefinic compounds should be contained in the mixture to give a sulfurized mixture with the desired oil solubility. It has been observed that in the individual formulations sulfurized terpenes such as sulfurized pine oils do not show the desired oil solubility, and it is essential that mixtures to be sulfurized contain enough of the second olefinic compound to result in the formation of a sulfurized preparation with the desired oil solubility. Generally, the equivalent ratio between the terpene and the second olefin will be from 1:20 to 10:1 and more generally the range will be from 1:10 to 5:1. More particularly, the equivalent ratio between terpene and other olefin will be from 1:10 to 2:1. As mentioned above, the second olefinic compound can be (i) at least one aliphatic, arylaliphatic or alicyclic olefinic hydrocarbon containing at least 3 carbon atoms, (ii) at least one unsaturated fatty acid or unsaturated fatty acid ester, (ii) at least one sulfurized derivative of (i) or ( ii), and (iv) mixtures thereof.

The equivalent ratio for the different olefinic compounds when mixtures are used can be varied within wide ranges and the particular equivalent ratios will depend on the raw materials available as well as the proportions desired in the sulfurized preparation.

It is advantageous to incorporate substances that can be used as sulphurisation promoters in the reaction mixture. These pro-motors which can be acidic, basic or neutral have been previously discussed.

The amount of promoter material used is generally 0.0005-2.09% of the total weight of terpene and olefinic compound. In the case of the preferred ammonia and amine catalysts, 0.0005-0.5 mol per mol combined weight preferred and 0.001-0.1 mol is particularly desirable.

Water is also present in the reaction mixture, either as a promoter or as a diluent for one or more of the above promoters. The amount of water, if present, is usually 1-25% by weight of the olefinic compound. However, the presence of water is not essential and when certain types of reaction equipment are used it may be advantageous to carry out the reaction under essentially water-free conditions.

When promoters are incorporated into the reaction mixture as described above, it is generally observed that the reaction can be carried out at lower temperatures and the product is generally lighter in colour.

The sulphurisation reagent used in this connection can for example be sulphur, a sulfur halide such as sulfur monochloride or sulfur dichloride, a mixture of hydrogen sulphide and sulfur or sulfur dioxide, or the like. Sulfur or mixtures of sulfur and hydrogen sulphide are often preferred. However, it would be clear that other sulfurizing agents can also be used if the conditions are right. Commercial sources of all sulfurization reagents are generally used for the purposes of the invention, and impurities commonly associated with these commercial products may be present without adverse results.

When the sulfurization reaction is carried out using sulfur alone, the reaction will be carried out only by heating the reagents with sulfur at temperatures from 50 to 250°C, usually from 150 to 210<e>C. The weight ratio between the combination of terpene and other olefin on the one hand and sulfur on the other is between 5:1 and 15:1, generally between 5:1 and 10:1. The sulphurisation reaction is carried out with effective agitation and generally in an inert atmosphere, for example under nitrogen. If any of the components or reagents are substantially volatile at the reaction temperature, the reaction container can be placed and kept under pressure. It is often advantageous to add the sulfur in portions to the mixture of the other components.

When mixtures of sulfur and hydrogen sulphide are used in the method of the invention, the amounts of sulfur and hydrogen sulphide per mol terpene and other olefin respectively 0.3 to 3 gram atoms and 0.1 to 1.5 mol. A preferred range is from 0.5 to 2.0 gram atoms and 0.4 to 1.25 moles and the most desirable ratios are 0.8 to 1.8 gram atoms and 0.4 to 0.8 moles. In rate drlft the components are introduced in quantities to give these ranges, in semi-continuous operation they can be mixed in any ratio but on a mass balance basis, they are present to be consumed in quantities within these conditions. Thus, for example, if the reaction vessel is initially charged with sulfur alone, the olefinic compound and the hydrogen sulphide are added in increments at a rate such that the desired ratio is achieved.

When mixtures of sulfur and hydrogen sulphide are used in the sulphurisation reaction, the temperature range for the sulphurisation reaction is usually from 50 to 350°C. The preferred range is 100 to 200°C while 120 to 180°C is most suitable. The reaction is often carried out under superatmospheric pressure, which can be and usually is autogenous pressure (that is, a pressure that develops naturally during the course of the reaction), but it can also be externally imposed pressure. The exact pressure developed during the reaction depends on such factors as the construction and operation of the system, the reaction temperature and the vapor pressure of reactants and products, and can vary during the course of the reaction. While it is generally preferred that the reaction mixture consist entirely of the components and reagents described above, the reaction may also be carried out in the presence of an inert solvent, (for example an alcohol, ether, ester, an aliphatic hydrocarbon, halogenated aromatic hydrocarbon and so on ) which is liquid within the temperature range used. When the reaction temperature is relatively high, for example 200°C, there may be some evolution of sulfur from the product, which is however avoided if a lower reaction temperature is used such as from 150-170°C.

The time required for the sulphurisation reaction will vary depending on the reagents, their ratios, the reaction temperature, the presence or absence of promoters and the purity of the reagents. When a mixture of sulfur and sulfur dioxide is used as sulphurizing agent and the reaction is carried out at elevated pressure in a closed container, the course of the reaction can conveniently be followed by monitoring the pressure in the reaction container. The reaction can usually be considered complete when the pressure equalizes to a constant value. After the preparation of the sulfurized mixture by the above-described method, it is usually preferred to remove essentially all low-boiling substances, characteristically by venting the reaction vessel or by distillation at atmospheric pressure, vacuum distillation or stripping, or passing an inert gas such as nitrogen through the mixture at suitable temperature and pressure. Any solids present in the reaction mixture can be conveniently removed in most cases by simply pouring off the liquid product. If further removal of solids is desired, such conventional techniques as filtration or centrifugation can be used.

In some cases, it may be desirable to treat the sulfurized product obtained according to the methods described here in order to reduce the active sulfur content.

The following examples shall illustrate the preparation of sulphurised terpene compounds and sulphurised mixtures of terpenes and olefinic compounds which are usable as component (B) according to the invention.

EXAMPLE XXIII

A reaction vessel is charged with 372 parts or 2 equivalents of a commercially available pine needle oil ("Sargent Welch"), and this is heated and stirred. 128 parts of sulfur are added slowly under nitrogen blowing while the reaction temperature is kept above 35°C. After the sulfur addition is complete, nitrogen is bubbled through the reaction mixture while it is heated to reflux at approx. 145°C. After a total reaction time of approx. 8 hours, the mixture is filtered through filter aid The filtrate is the desired sulfurized product containing 23.3556 sulfur (theoretical 25.656).

EXAMPLE XXIIH

The procedure of Example 23 was repeated except that the reaction mixture comprised 186 parts of pine needle oil (1 equivalent) and 32 parts of sulfur (1.0 equivalent). The product thus obtained had a sulfur content of 15.656 while the theoretical value was 14.6856.

EXAMPLE XXV

372 parts or 2 equivalents of pine needle oil and 96 parts or 3 equivalents of sulfur are added to a reaction vessel. After all the sulfur had been added, the mixture was heated to 150<*>C under nitrogen blowing and the mixture was kept at this temperature for approx. 10 hours. The reaction mixture was filtered through filter aid and the filtrate was the desired product at a sulfur content of 17.2556, theoretical value 20.556.

EXAMPLE XXVI

372 parts, or 2 equivalents of pine needle oil are added to a reaction vessel and the oil is heated while stirring. 190 parts or 6 equivalents of sulfur are slowly added to the stirred oil and after the addition is complete, nitrogen is blown through the reaction mixture which is heated to a temperature of approx. 145°C. 5.62 parts of triethanolamine are added and heating of the mixture is continued under reflux until the sulfur appears to have dissolved. The mixture is filtered and the filtrate is the desired product with a sulfur content of 25.456 where the theoretical value is 33.856.

EXAMPLE XXVII

A mixture of 111 parts or 0.5 mol of a distilled Cm, α-olefin and 93 parts or 0.5 mol of pine needle oil is prepared and heated with stirring in a reaction vessel. 64 parts corresponding to 2 mol of sulfur are added slowly and the reaction temperature is raised to approx. 170°C. The reaction mixture is kept at a temperature of 160° C with nitrogen blowing. A certain reflux of the lighter fractions of the pine needle oil is observed. The reaction mixture is then cooled and filtered through a filter aid. The filtrate is the desired product containing 25.1656 of sulphur, the theoretical value being 23.956.

EXAMPLES XXVIII-XXXI

The general procedure in Example 27 is repeated except that the equivalent ratio of olefin:pine needle oil:sulfur is varied and in Example 5 a promoter system consisting of 0.043 equivalents of triethanolamine and 0.01 equivalent of 2,5-bis(tert-octyldithio)thiadiazole is used as promoter for each equivalent of pine needle oil and mixture. Further details in connection with these examples can be found in the following table

IN.

EXAMPLE XXXII

A mixture of 186 parts or 1 equivalent of pine needle oil and 168 parts or 1 equivalent of polypropylene is prepared and 96 parts or 3 equivalents of sulfur are added with stirring. The reaction mixture is heated to a temperature of approx. 170°C with nitrogen blowing and kept at this temperature for 10 hours. The reaction mixture is then cooled and filtered through filter aid. The filtrate is the desired product with a sulfur content of 16.7996, the theoretical value being 21.3356.

EXAMPLE XXXIII

The mixture of 168 parts or 1 equivalent of pine needle oil, 126 parts or 1 equivalent of nonene and 192 parts or 6 equivalents of sulfur is prepared and heated to reflux at approx. 135°C for 2 hours. After cooling overnight, 10.1 parts or 0.1 equivalent of triethylamine and 4.3 parts of 2,5-bis(tert-octyldithio)thiadiazole are added as promoter. The mixture is heated to 135-140°C with nitrogen blowing until the reaction mixture becomes clear. The mixture is heated to reflux for another 6 hours and filtered through a filter aid. The filtrate is the desired product containing 33.4956 sulfur, theoretical value 37.156.

EXAMPLE XXXIV

Polypropylene (252 parts, 1.5 equivalents) is charged to a reaction vessel equipped with a condenser and agitator. The propylene is stirred and 48 parts or 1.5 equivalents are added. This reaction mixture is heated to approx. 170°C and kept at this temperature for approx. 5 hours and cool. Pine needle oil (279 parts, 1.5 equivalents) is added to the reaction mixture which is then heated to a temperature of approx. 150°C and kept at this temperature with nitrogen blowing for approximately 8 hours. The mixture is cooled and filtered through a filter aid to obtain the desired product with a sulfur content of 8.3656, theoretical value 8.256.

The relative amounts of metal salts of dithiocarbamic acid (component A) and sulfurized organic compound (component B) can vary over a wide range depending on the intended use of the preparation. In general, the weight ratio between metal salt (A) and sulfurized adduct (B) is within the range 1:10 to 50:1, the exact amounts of the two components incorporated in the preparation according to the invention being easily determined by the person skilled in the art.

The preparations according to the invention also contain at least one further corrosion-inhibiting material, component (C). In one embodiment, the corrosion-inhibiting component (C) is at least one dimercaptothiadiazole or an oil-soluble derivative thereof. Such substances provide corrosion-inhibiting properties and, in particular, such preparations are useful for inhibiting copper activity such as copper staining.

The mercaptothiadiazoles which can be used according to the invention as starting materials for the production of the oil-soluble derivatives containing the dimercaptothiadiazole nucleus have the following structural formulas and names:

2,5-dimercapto-1,3,4-thiadiazole 3,5-dimercapto-1,2,4-thiadiazole 3,4-dimercapto-1,2,5-thiadiazole

4,5-dimercapto-1, 2,3-thiadiazole

One of the most readily available and the one preferred for the purposes of the invention is 2,5-dimercapto-1,3,4-thiadiazole. This compound is sometimes called below DMTD. However, it should be clear that any of the other dimercaptothiadiazoles may be used for all or some

DMTD.

DMTD is conveniently prepared by reacting one mole of hydrazine or a hydrazine salt with two moles of carbon disulphide in an alkaline medium, followed by acidification.

When the preparations according to the invention are to be used in the production of lubricating oils, component (C) will be DMTD or derivatives of DMTD. Derivatives of DMTD are described in the known art and any such compound can be incorporated into the preparations according to the invention. The production of certain derivatives of DMTD is described in E.K. Field's "Industrial and Engineering Chemistry", 49, pp. 1361-4 (September 1957). For the production of the oil-soluble derivatives of DMTD, it is possible to use already produced DMTD or to produce DMTD in situ and then add the substance to be reacted with DMTD.

TJS-PS 2,719,125, 2,719,126 and 3,087,937 describe the preparation of various 2,5-bis-(hydrocarbondithio)-1,3,4-thiadiazoles. The hydrocarbon group can be aliphatic or aromatic including cyclic, alicyclic, aralkyl, aryl and alkaryl. Certain preparations are effective corrosion inhibitors for silver, silver alloys and similar metals. Such polyolefins as can be represented by its following general formula

where R and R' can be the same or different hydrocarbon groups and x and y whole numbers from 0 to 8, the sum of x and y being at least 1. A method for producing such derivatives is described in US-PS 2,191,125 and comprises reacting DMTD with a suitable sulfenyl chloride or by reacting dimercaptodiathiazole with chlorine and reacting the resulting disulfenyl chloride with a primary or tertiary mercaptan. Suitable sulfenyl chlorides that can be used in it

first procedure can be achieved by chlorination of a mercaptan (RSH or R<*>SH) with chlorine in carbon tetrachlorld. In a second procedure, DMTD is chlorinated to form the desired bissul-phenyl chloride which is then treated with at least one mercaptan (RSH and/or R'SH). Reference should be made to the description in US-PS 2,179,125, 2,719,126 and 3,087,937 when it comes to the correct description of derivatives of DMTD.

US-PS 3,087,932 describes a one-step process for the preparation of 2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazole. The procedure involves reacting either DMTD or an alkali metal or ammonium salt thereof and a mercaptan in the presence of hydrogen peroxide and a solvent. Oil-soluble or oil-dispersible reaction products of DMTD can also be prepared by reacting DMTD with a mercaptan and formic acid. Preparations produced in this way are described in US-PS 2,749,311. Any mercaptan can be used in the reaction although aliphatic and aromatic mono- or polymer captans containing from 1 to 30 carbon atoms are preferred. Reference should be made to the description in US-PS 3,087,932 and 2,749,311 regarding their description of DMTD.

Carbocyclic esters of DMTD of the general formula

where R and R' are hydrocarbon groups such as aliphatic, aryl and alkaryl groups containing from 2 to 30 or more carbon atoms are described in US-PS 2,760,933. These esters are produced by reacting DMTD with an organic acid halide (chloride) and a molar ratio of 1:2 at a temperature of 25 to 130°C. Suitable solvents such as benzene or dioxane can be used to facilitate the reaction. The reaction product is washed with dilute aqueous alkali to remove

hydrogen chloride and any unreacted carboxylic acid. Reference should be made to the description in US-PS 2,760,933 when it comes to the description of the various DMTD derivatives that can be used in the preparations of the invention.

Condensation products of α-halogenated aliphatic monocarboxylic acids of at least 10 carbon atoms with DMTD are described in US-PS 2,836,564. These condensation products are generally characterized by the following formula

where R is an alkyl group with at least 10 carbon atoms. Examples of α-halogenated aliphatic fatty acids that can be used are α-bromo-lauric acid, α-chloro-lauric acid, α-chlorostearic acid and so on. Reference should be made to US-PS 2,836,564 when it comes to the description of derivatives of DMTD.

Oil-soluble reaction products of unsaturated cyclic hydrocarbons and unsaturated ketones are described in US-PS 2,764,547 and 2,799,652. Examples of unsaturated cyclic hydrocarbons described in the '547 patent are styrene, α-methylstyrene, pinene, dipene, cyclopentadlene, and so on. The unsaturated ketones described in US-PS 2,799,652 include aliphatic, aromatic or heterocyclic unsaturated ketones containing from 4 to 40 carbon atoms and from 1 to 6 double bonds. Examples are mesityl oxide, furon, isophoron, benzalaceto-phenone, furfuralacetone, difurfurylacetone and so on.

US-PS 2,765,289 describes products obtained by reacting DMTD with an aldehyde and a diarylamine in molar proportions of from 1:1:1 to 1:4:4. The resulting products are suggested to have the general formula

where R and R' are the same or different aromatic groups and R" is hydrogen, an alkyl group or an aromatic group. The aldehydes which can be used in the preparation of such products are represented by formula X and include aliphatic and aromatic aldehydes containing from 1 to 24 carbon atoms , specific examples of such aldehydes are formaldehyde, acetaldehyde, benzaldehyde, 2-ethylhexylaldehyde etc. Component (C) in the preparations according to the invention can also be amine salts of DMTD such as those having the formula where Y is hydrogen or the amino group

where R is an aliphatic, aromatic or heterocyclic group and R1 and R<2> independently are aliphatic, aromatic or heterocyclic groups containing from 6 to 60 carbon atoms. The amine used in the preparation of the amine salts can be aliphatic or aromatic mono- or polyamines, and the amines can be primary, secondary or tertiary amines. Specific examples of suitable amines are hexylamine, dibutylamine, dodecylamine, ethylenediamine, propylenediamine, tetraethylenepentamine and mixtures thereof. Reference is made to US-PS 2,910,439 when it comes to listing suitable amine salts.

Dithiocarbamate derivatives of DMTD are described in US-PS 2,690,999 and 2,719,827. Such preparations can be represented by the following formulas:

where the R group is straight or branched saturated or unsaturated hydrocarbon groups selected from alkyl, aralkyl and alkaryl groups. Reference is made to these patents when it comes to thiadiazyldithiocarbamates which can be used as component (C).

US-PS 2,850,453 describes products obtained by reacting DMTD, an aldehyde and an alcohol or an aromatic hydroxy compound in a molar ratio of 1:2:1 to 1:6:5. The aldehyde that is used can be an aliphatic C 2 gg aldehyde or an aromatic or heterocyclic C 5 3 Q aldehyde. Examples of suitable aldehydes are formaldehyde, acetaldehyde, benzaldehyde. The reaction can be carried out in the presence or absence of suitable solvents by (a) mixing all reactants together and heating the whole, (b) by first reacting an aldehyde with the alcohol or aromatic hydroxy compound and then reacting the resulting intermediate with thiadiazole, or ( c) reacting the aldehyde with thiadiazole first and then the resulting intermediate with the hydroxy compound. Reference should be made to US-PS 2,850,453 when it comes to thiadiazole derivatives that can be used as component (C).

TJS-PS 2,703,784 describes products obtained by reacting DMTD with an aldehyde and a mercaptan. The aldehydes are equivalent to those described in TJS-PS 2,850,453, and the mercaptans can be aliphatic or aromatic mono- or polymer captans containing from 1 to 30 carbon atoms. Examples of suitable mercaptans include ethyl mercaptan, octyl mercaptan, thiophenol and so on.

The preparation of 2-hydrocarbyldithio-5-mercapto-1,3,4-thiadiazoles of the formula

where R<*> is a hydrocarbyl substituent, described in TJS-PS 3,663,561. The preparations are produced by oxidative coupling of equimolecular amounts of a hydrocarbyl mercaptan and DMTD or its alkali metal mercaptide. The preparations are stated to be excellent sulfur scavengers and can be used to prevent copper corrosion due to active sulphur. The mono-mercaptans used in the preparation of the compounds are represented by the formula

where R<*> is a hydrocarbyl group containing from 1 to approx. 280 carbon atoms. A peroxy compound, a hypohalide or air, or mixtures thereof, can be used to promote oxidative coupling. Specific examples of monomer captans are methyl mercaptan, in isopropyl mercaptan, hexyl mercaptan, decyl mercaptan and long-chain alkyl mercaptans, for example mercaptans derived from propene polymers and isobutylene polymers, especially polyisobutylenes, with 3 to 70 propene or isobutylene units per molecule. Reference should be made to US-PS 3,663,561 when it comes to the identification of DMTD derivatives that can be used as component (C).

Other substances which can be used as component (C) in the preparations according to the invention are obtained by reacting a thiadiazole, preferably DMTD, with an oil-soluble dispersant, preferably an essentially neutral or acidic carboxylic dispersant in a diluent by heating the mixture to over 100° C. This procedure and the thereby obtained derivatives are described in US-PS 4,136,043. The oil-soluble dispersants used in the reaction with the thiadiazoles are often identified as "ashless dispersants". Various types of suitable ashless dispersants which can be used in the reaction are described in the '043 patent.

Another substance that can be used as component (C) in the preparations according to the invention is obtained by reacting a thiadiazole, preferably DMTDD, with a peroxide, preferably hydrogen peroxide. The resulting nitrogen- and sulfur-containing preparations are then reacted with a polysulfide, mercaptan or an amino compound (especially oil-soluble, nitrogen-containing dispersants). This procedure and the derivatives thereby produced are described in US-PS 4,246,126.

US-PS 4,140,643 describes nitrogen- and sulphur-containing preparations which are oil-soluble and which are prepared by reacting a carboxylic acid or an anhydride thereof containing up to 10 carbon atoms and with at least one olefinic bond, with preparations of the type described in US-PS 4,136,043. The preferred acid or anhydride is maleic anhydride. Reference is made to US-PS 4,136,043 and 4,140,643 regarding their description of substances usable as component (C).

US-PS 4,097,387 describes DMTD derivatives prepared by reacting a sulfur halide with an olefin to thereby obtain an intermediate product which is then reacted with an alkali metal salt of DMTD. More recently, US-PS 4,487,706 describes a DMTD derivative prepared by reacting an olefin, sulfur dichloride and DMTD in a one-step reaction. The olefins usually contain from 6 to 30 carbon atoms. Reference is made to TJS-PS 4,097,387 and 4,487,706 for their description of oil-soluble DMTD derivatives which can be used as component (C).

The amount of further corrosion inhibitor such as the oil-soluble derivatives of dimercaptothiadiazole, component C, included in the preparations according to the invention, can vary within wide ranges depending on the intended end use for the preparation. Where the preparations according to the invention are to be used in the production of lubricating oil formulations, the amount of thiadiazole derivative including the preparation should be sufficient to give the desired corrosion-inhibiting properties to the final lubricating oil. In general, the weight ratio between auxiliary corrosion inhibitor (C) and mixture of components (A) and (B) will be from 0.001:1 to 0.5:1.

The preparations according to the invention can also contain other substances which are usable to give further desirable properties to the preparation. Substances which have desirable properties and which can be incorporated into the preparations according to the invention are, for example, detergents and dispersants of the ash-forming or ash-free type, extreme pressure agents, antiwear agents, color stabilizers, antifoam agents and so on.

In one embodiment of the invention, in addition to components (A), (B) and (C), the preparations according to the invention will contain at least one oil-soluble dispersant/detergent, component (D). This can be of the ash-forming or ash-free type.

The ash-forming detergents are exemplified by oil-soluble neutral and basic salts of alkali or alkaline earth metals with sulphonic acids or carboxylic acids. The most frequently used salts of such acids are those of sodium, potassium, lithium, calcium, magnesium, strontium and barium.

The term "basic salt" is used to denote metal salts where the metal is present in stoichiometrically greater amounts than the organic acid group. The commonly used methods for preparing basic salts involve heating a mineral oil solution of an acid with a stoichiometric excess of a metal neutralizing agent such as a metal oxide, hydroxide, carbonate, bicarbonate or sulfide at a temperature of 50°C and filtering of the resulting mass. The use of a "promoter" in the neutralization step to support the incorporation of a large excess of metal is also known. Examples of compounds that can be used as a promoter include phenolic substances such as phenol, naphthol, alkylphenol, thiophenol, sulfurized alkylphenol and condensation products of formaldehyde with a phenolic substance; alcohols such as methanol, 2-propanol, octyl alcohol, cellosolv, carbitol, ethylene, glycol, stearyl alcohol and cyclohexyl alcohol; and amines such as aniline, phenylenediamine, phenothiazine, phenyl-p<->naphthylamine and dodecylamine. A particularly effective method of preparing the basic salts is mixing an acid with an excess of a basic alkaline earth metal neutralizing agent and at least one alcohol promoter, and carbonating the mixture at an elevated temperature such as 60-20C<T>C.

Ashless detergents and dispersants are so called in spite of the fact that, depending on their constitution, they may, on combustion, yield a non-volatile material such as boron oxide; however, they usually do not contain metal and therefore do not produce any metal-containing ash when burned. Many types are known in the art and many of these are suitable for use in the lubricant preparations according to the invention. The following are illustrative: (1) Reaction products of carboxylic acids (or derivatives thereof) containing at least 34 and preferably at least 54 carbon atoms with nitrogen-containing compounds such as amines, organic hydroxy compounds such as phenols and alcohols, and/or basic inorganic substances. Examples of these "carboxylic dispersants" are described in GB-PS 1,306,529 and in many TJS patents including US-PS: (2) Reaction products of relatively high molecular weight aliphatic or alicyclic halides with amines, preferably oleylalkylene polyamines. These can be characterized as "amine dispersants" and examples are for example described in US-PS: (3) Reaction products of alkylphenols where the alkyl group contains at least 30 carbon atoms with aldehydes (especially formaldehyde) and amines (especially polyalkylene polyamines), which can be characterized as " Mannich dispersants". These substances are described in US-PS: (4) Products obtained by post-treatment of carboxylic, amine or Mannich dispersants with reagents such as urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, two connections or the like. Examples of these are described in US-PS: (5) Interpolymers of oil-solubilizing monomers such as decyl methacrylate, vinyl decyl ether and high molecular weight olefins with monomers containing polar substituents, for example aminoalkyl acrylates or -acrylamides and polyoxyethylene-substituted acrylates. These can be characterized as "polymeric" dispersants and examples are found in US-PS:

When the detergent/dispersant, component (D), is incorporated into the preparations according to the invention, the weight ratio between component (D) and the total weight of components (A) and (B) will lie within the range 1:0.5 to 1:5.

The preparations according to the invention containing the components

(A), (B) and (C) and/or (D) can be used in lubricating oil mixtures. The preparations according to the invention can be added directly

to the lubricant. Preferably, however, it is diluted with a substantially inert, usually liquid organic diluent such as mineral oil, naphtha, benzene, toluene or xylene, to give an additive concentrate. These concentrates usually contain from 20 to 90% by weight of the preparation according to the invention and may additionally contain one or more other additives known in this technique and described below. The rest of the concentrate is the essentially inert, usually liquid diluent.

The preparations according to the invention can be used in particular to improve the properties of lubricants that contain little or no phosphorus, especially lubricants that contain less than 0.156 and generally less than 0.0856 phosphorus. In some cases, the lubricating mixtures do not contain phosphorus. In general, it is phosphorus that is present in the lubricating oil mixtures according to the invention in the form of a phosphorodithioate and more particularly as a group II metal phosphorodithioate, organic phosphites such as trialkyl phosphites and so on. Lubricating oil preparations containing less than 0.1 wt-56 phosphorus and more particularly less than 0.08 wt-# phosphorus are generally known as "low phosphorus lubricating oil". In such low-phosphorus or non-phosphorus lubricants, it is preferred to use a sulphurised Diels-Alder adduct as component (B), produced by reacting sulfur with an adduct in a molar ratio of less than 1:1.

The lubricant mixtures according to the invention comprise a major amount of an oil of lubricant viscosity including natural and synthetic lubricating oils and mixtures thereof.

Natural oils are animal oils and vegetable oils (for example castor oil, lard oil) as well as mineral lubricating oils such as liquid petroleum oils and solvent treated or acid treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic naphthenic type. Oils of lubricant viscosity derived from coal or shale are also usable. Synthetic lubricating oils are hydrocarbon oils and halogen-substituted hydrocarbon oils such as polymerized and interpolymerized olefins (for example, polybutylenes, polypropylenes, propylene isobutylene copolymers, chlorinated polybutylenes, and so on); poly(1-hexenes), poly(1-octenes), poly(1-decenes) and so on and mixtures thereof; alkylbenzenes (for example, dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexylbenzenes, and so on); polyphenyls (for example, biphenyls, terphenyls, alkylated polyphenyls, and so on); alkylated diphenyl ethers and alkylated diphenyl sulfides and derivatives, analogs and homologues thereof and the like.

Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxy group has been modified by esterification, etherification and so on constitute another class of known synthetic lubricating oils which can be used. These are exemplified by the oils produced by the polymerization of ethylene oxide or propylene oxide, alkyl and aryl ethers of these polyoxy-alkylene polymers (for example methyl polyisopropylene glycol ether with an average molecular weight of approx. 1000, diphenyl ether from polyethylene glycol with a molecular weight of 500-1000, diethyl ether of polypropylene glycol with a molecular weight of 1000-1500 and so on) or mono- and polycarboxylic acid esters thereof, for example acetic acid esters, mixed C3~g fatty acid esters, or C13-oxybacid diesters of tetraethylene glycol.

Another suitable class of synthetic lubricating oils which may be used include the esters of dicarboxylic acids (for example, phthalic, succinic, alkyl succinic, alkenyl succinic, maleic, azelaic, suberin, sebacin, fumaric, adipic, linoleic, malonic, alkylmalonic, alkenylmalonic acids and so on) with a number of alcohols (for example butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol and so on). Specific examples of these esters are dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of the linoleic acid dimer, the complex ester obtained by reaction of one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.

Esters that can be used as synthetic oils are also those made from C5_i2-monocarboxylic acids and polyols and polyol ethers such as neopentylglycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol and so on.

Silicon-based oils such as the polyalkyl, polyaryl, poly-alkoxy, or polyaryloxysiloxane oils and silicate oils are another useful class of synthetic lubricants (for example, tetraethyl silicate, tetraisopropyl silicate, tetra-2-ethylhexyl)-silicate, tetra-(4-methyl-hexyl) silicate, tetra-(p-tert-butyl-phenyl)s silicate, hexy-1-(4-methyl-2-pentoxy)di s iloxane, poly(methyl)siloxane, poly(methylphenyl)siloxanes and so on). Other synthetic lubricating oils include liquid esters of phosphorous acids (for example, tricresyl phosphate, trioctyl phosphate, the diethyl ester of decanephosphonic acid, and so on), polymeric tetrahydrofurans, and the like.

Refined, refined and re-refined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type described above, can be used in the compositions according to the invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from the retorting operation, a petroleum oil obtained directly from the primary distillation or an ester oil obtained directly from an esterification process and used without further treatment will be an unrefined oil. Refined oils are similar to unrefined oils except that they have been further processed in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art, such as solvent extraction, secondary distillation, acid or base extraction, filtration, percolation and so on. Re-refined oils are obtained by processes similar to those used to obtain refined oils with those applied to refined oils that have already been in use. Such re-refined oils are also known as reprocessed oils or the like and are often additionally treated by techniques aimed at removing used additives and oil breakdown products.

The preparations according to the invention will usually be used in the smelting mixtures according to the invention in an amount sufficient to provide the desired property improvement such as improved oxidation-corrosion inhibition, improved anti-wear and/or extreme pressure properties. More generally, this amount will be from 0.001 to 20 wt-# of the particular oil in which they are used. The optimum oil used in a given lubricant obviously depends on the other ingredients in the mixture, the intended operating conditions and the particular additives used. In lubricating compositions operating under extremely adverse conditions such as marine diesel engine lubricating compositions, the compositions may be present in the lubricant in amounts up to 30% by weight or more, of the total weight of the lubricating composition.

In a particularly preferred embodiment, the lubricating oil mixture will comprise an oil of lubricant viscosity and the components (A), (B) and (C) as described above. In general, however, component (D) will also be incorporated into the lubricants. The invention also includes the use of other additives in the lubricant mixtures according to the invention. Such additives are, for example, oxidation inhibiting agents, pour point reducing agents, extreme pressure agents, antiwear agents, color stabilizers and antifoaming agents.

Further extreme pressure agents and corrosion and oxidation inhibiting agents which can be incorporated into the lubricants according to the invention are exemplified by chlorinated aliphatic hydrocarbons such as chlorinated wax; organic sulfides and polysulfides such as benzyl disulfide, bis(chlorobenzyl) disulfide, dibutyl tetra-sulfide, sulfurized methyl ester of oleic acid, sulfurized alkylphenol, sulfurized dipentane and sulfurized terpene. Group II metal phosphorodithioates are zinc dicyclohexyl phosphorodithioate, zinc dioctyl phosphorodithioate, barium di(heptylphenyl) phosphorodithioate, cadmium dinonyl phosphordithioate, and the zinc salt of a phosphorodithioate prepared by reacting phosphorus pentasulfide with an equimolecular mixture of isopropyl alcohol and n-hexyl alcohol. When it is desired to formulate lubricating oils containing small amounts of phosphorus, such phosphorus dithioates should be avoided if possible.

Many of the above-mentioned extreme pressure agents and corrosion-oxidation inhibitors also serve as anti-wear agents. Zinc dialkyl phosphorodithioates are well known examples. Pour point reducers are a particularly useful type of additive that is often incorporated into the lubricating oil described. The use of such pour point depressants in oil based compositions to improve the low temperature properties of oil based compositions is well known in the art, see for example page 8 of "Lubricant Additives" of CV. Smalheer and R. Kennedy Smith (Lezius-Hiles Co, publishers, Cleveland, Ohio, 1967).

Examples of usable pour point depressants are polymethacrylates; polyacrylates; polyacrylamides; condensation products of halogenated paraffin waxes and aromatic compounds; vinyl carboxylate polymers; and terpolymers of dialkyl fumarates, vinyl esters of fatty acids and alkyl vinyl ethers. Pour point depressors that can be used for the purposes of the invention, their manufacture and use are described in TJS-PS 2,387,501; 2,015,748; 2,655,479; 1,815,022; 2,191,498; 2,666,746; 2,721,877; 2,721,878 and 3,250,715.

Antifoam agents are used to reduce or prevent the formation of stable foam. Typical such are silicones or organic polymers. Additional antifoam compositions are described in "Foam Control Agents" by Benry T. Kerner (Noyes Data Corporation, 1976) pp. 125-162).

The invention is illustrated in more detail by the following examples where all parts and percentages are on a weight basis of the total mixture unless otherwise stated.

Example 2 Example 3 Example 4 Example 5 Example 6

Example 7

Example 8 Example 9

Example 10 Example 11

The lubricating oil mixtures containing the preparations according to the invention as illustrated above show improved corrosion-inhibiting, antioxidant, anti-wear and extreme pressure properties. When the lubricating oil mixture according to the invention contains essentially no phosphorus and a sulphurised Diels-Alder adduct with a molar ratio of sulphur:adduct of less than 1:1, good compatibility with nitriti seals is achieved.

Claims (9)

1. Oil-soluble lubricant preparation comprising a main amount of an oil of lubricant viscosity and a smaller, property-improving amount of an oil-soluble preparation, characterized in that it comprises : (A) at least one metal salt of at least one dithiocarbamic acid with the formula wherein Ri and Rg are each independently hydrocarbyl groups in which the total number of carbon atoms in R^ and Rg is sufficient to render the metal salt oil-soluble; and (B) at least one oil-soluble sulfurized olefin containing the reaction product of sulfur and a Diels-Alder adduct in a molar ratio of less than 1.7:1, wherein the weight ratio of (A):(B) is in the range of 1:10 to 50: 1; and (C) at least one auxiliary corrosion inhibitor in the form of an oil-soluble derivative of a dimercaptothiadiazole, the weight ratio (C):(A)+(B) being 0.001:1 to 0.5:1; and the lubricant preparation contains less than 0.1 wt-SÉ phosphorus. 2. Preparation according to claim 1, characterized in that Ri and Rg are alkyl groups containing at least 2 carbon atoms and where the metal in the metal salt (A) is one. polyvalent metal. 3. Preparation according to claim 1, characterized in that the sulfurized olefin is a sulfurized Diels-Alder adduct of at least one dienophile with at least one aliphatic conjugated diene, and that the dienophile comprises an α, 3-ethylenically unsaturated aliphatic carboxylic acid ester, carboxylic acid amide, halide, nitrile, aldehyde, ketone or mixtures thereof. 4. Preparation according to claim 3, characterized in that the aliphatic conjugated diene corresponds to the formula where R to R<5> are each independently selected from hydrogen, alkyl, halogen, alkoxy, alkenyl, alkenyloxy, carboxyl, cyano, amino, alkylamino, dialkylamino, phenyl and phenyl substituted with one to three substituents corresponding to R to R<5> , or R, R<2>, R<3> and R<5> are as indicated and R<1> to R<4> are alkylene groups joined to form a cyclic diene. 5. Preparation according to claim 3, characterized in that the dienophile is further characterized in that it contains at least one but not more than two -C(0 )0R5 groups where Rg is a residue of a saturated aliphatic alcohol of up to 40 carbon atoms. 6. Preparation according to claim 5, characterized in that the diene is 1,3-butadiene. 7. Preparation according to claim 4, characterized in that the dienophile is an ester of acrylic acid or methacrylic acid. 8. Preparation according to claim 1, characterized in that it further contains (D) an oil-soluble dispersant/detergent where the weight ratio (D):(A) + (B) lies within the range 1:0.5 to 1:5. 9. Preparation according to claim 1, characterized in that (B) is the reaction product of sulfur and a Diels-Alder adduct in a molar ratio of less than 1:1.