US3451166A - Mineral lubricating oil containing sulfurized alkylated aryl amine - Google Patents

Description

United States Patent 3,451,166 MINERAL LUBRICATING OIL CONTAINING SULFURIZED ALKYLATED ARYL AMINE Jerome Panzer, Roselle Park, N..l., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Sept. 26, 1966, Ser. No. 581,686 Int. Cl. Cm 1/38, 1/34, 1/08 U.S. Cl. 252-47.5 7 Claims ABSTRACT OF THE DISCLOSURE Novel chemical compounds are prepared by reacting primary or secondary aryl amines, for example, C-alkyl phenyl diamines, C-alkyl diphenyl amines, C-alkyl N- phenyl phenylene diamines, C-alkyl anilines, C-alkyl toluidines or C-alkyl xylidine's, wherein the alkyl group is attached to the aryl nucleus and contains from 6 to 250 carbon atoms, with a halide of sulfur, wherein the sulfurization is carried out at a temperature between about 80 and 300 F. for between about 30 minutes and about 24 hours. These novel sulfurized dispersants are particularly useful in mineral lubricating oil compositions when used in an amount ranging between about 0.05

sludge dispersant properties to the lubricating oils.

The present invention relates to the preparation of sulfurized amines and to lubricating oils containing the same. These sulfurized amines are prepared by sulfurizing a primary or secondary amine with a sulfur halide to yield an oil-soluble, sulfurized, amino composition which, 'when added in minor amounts to lubricating oils particularly those involved in heavy duty operations such as in gas engines and railroad Diesel engines, alfords excellent sludge dispersancy and antioxidant properties.

Numerous addition agents have heretofore been prepared for use in heavy fuels and lubricating oils in order to improve oxidation stability, dispersancy, anticorrosive properties, freedom from formation of soluble and insoluble materials, protection from rust and corrosion, and the like. Good oxidation stability and good dispersancy of sludge along with good detergency have become essential requirements for lubricants particularly those employed in heavy duty operations such as those lubricants used in association with railroad Diesel engines and gas engines. By dispersancy is meant the prevention of the deposition of soluble material and by detergency is meant the quality of removing deposits and preventing the deposition of solid materials after they have been formed and/or deposited on the parts of internal combustion engines. In the field of railroad Diesel engine lubricants and gas engine lubricants, the criteria that must be met by the lubricants satisfactorily employed in such usages include high oxidation stability, the retention of viscosity during use, and the prevention of wear, rust and corrosion during the operation of the engines lubricated with such oils. Additionally, in these heavy duty operations, the choice of a proper additive for the oils used is necessarily selective because of the presence of copper-leadcontaining bearings; this type of bearing being unusually highly susceptible to wear and corrosion. The oil or any compounded oil employed in these operations must have a minimum of corrosive attack upon such hearings in addition to having the heretofore mentioned desirable properties. There is constant demand for lubricants of increased oxidation stability which exhibit viscosity stability, resist oxidation and, at the same time, satisfy the increasingly stringent requirements for engine cleanliness, bearing wear reduction, and corrosion protection Patented June 24, 1969 of those internal parts of the engine constantly coming into contact with the lubricating oil employed.

It has now been discovered that anticorrosive, antioxidant, ashless dispersants are produced by sulfurizing certain types of primary and secondary amines with a sulfur halide at a temperature of between about F. and about 300 F. for about 30 minutes to about 24 hours. These novel, oil-soluble, sulfurized amines or mixed amido-amines exhibit vastly improved effectiveness from the standpoint of bearing wear, corrosiveness, oxidation stability, sludge dispersancy and the like when employed in lubricating oils designed for use in heavy duty Diesel and gas engines. In carrying out the sulfurizing reaction, the mole ratio of amine to sulfur halide may vary between about 1:1 and about 1:5, preferably between about 1:1 and about 1:2. -In all cases, the amine, as distinguished from the amido-amine, contains in its molecule at least one aromatic group, usually a benzene nucleus. The one or more amino groups may be attached directly to this nucleus or none of the amino groups need be attached to this nucleus but at least one long chain alkyl radical, i.e., of 6 or more carbon atoms, should be so attached. Several different types of compounds, all of which may be broadly classified as primary or secondary amines, are useful as starting materials for the sulfurizing reaction.

Typical specific alkaryl amines that may be used are: C-alkyl ortho, meta, or para-phenylene diamine, C-alkyl diphenyl amine, C-alkyl ditolyl amine, the C-alkyl N phenyl ortho, meta or para-phenylene diamines, C-alkyl aniline or C-alkyl toluidine, C-alkyl xylidines, etc., wherein the alkyl is at least six carbons, preferably C to C with two or more such groups attached to aromatic carbon atoms also included within this group of reactants. Also useful as reactants are the alkyl amido polyalkylene polyamines, alkyl aralkyl amines such as C-polyisobutenyl dibenzyl amine, the polyisobutenyl nuclear-substituted phenyl amido tetraethylene pentamines, the condensate of nonyl phenol, formaldehyde and ethylene diamine, and the polyisobutenyl nuclear-substituted benzoic acid amide of ethylene diamine, tetraethylene tetramine, or tetraethylene pentamine. In general, the oil solubility properties are improved where at least one alkyl radical is directly attached to the benzene nucleus, which alkyl radical contains between about 40 and about 250 carbon atoms per alkyl group. A specific amido-amine found to be most useful is the polyisobutenyl-substituted propionic acid amide of tetraethylene pentamine. This does not contain a benzene nucleus but it has been found to be particularly useful as a material which may be treated with a sulfur halide and that material used as an additive for heavy duty lubricating oil compositions. Also, combinations of two or more of these sulfurized amines may be employed to achieve a lubricating oil composition having the desired dispersancy, anti-oxidant, and detergency properties in the final lubricating oil composition. In those cases in which an amido group is present in the starting materials, care should be taken to insure some free amino groups left unreacted; for less effective results are achieved in the treatment of an amine, containing no free amine groups, with sulfur halide in contrast with the results achieved where the amine compound also contains one or more free primary or secondary amine groups.

The polyisobutenyl radical previously mentioned will generally have a molecular weight between about 700 and about 1,500, more particularly, about 780 to about 1,000. It is prepared from polyisobutylene by methods conventionally available in the literature. Typical procedures for the preparation of polyisobutylene are taught in British Patent No. 983,040. Polyisobutylene is preferable to use as a starting material because it has a lesser tendency to gel the final product as compared with some of the other poly, alpha, mono-olefins such as polyethylene, polypropylene or ethylene-propylene copolymer. The polyisobutylene may be halogenated with chlorine or bromine at a temperature of between about 50 F. and about 300 F. using a suitable solvent such as hexane, heptane or carbon tetrachloride. The reaction time of between about two hours and about five hours is generally sufficient and the chlorinated or brominated polyisobutylene is then reacted with an alpha,beta-unsaturated monocarboxylic acid of 5 to 8 carbon atoms per molecule or with benzoic acid. Typical unsaturated carboxylic acids which may be used are acrylic acid, methacrylic acid, crotonic or isocrotonic acid, and the like.

Any of the usual polyethylene polyamines may be employed in forming the amide so long as free amino groups remain in the final product. No need is seen for mentioning the methods of production of aniline, diphenyl amine and the heretofore mentioned alkyl aromatic amines. In the case of the production of carbon-substituted polyisobutenyl diphenyl amine, however, the reaction is carried out using a Friedel-Crafts reaction. This results in the production of C-polyisobutenyl diphenyl amine which may then be treated with a sulfur halide as hereinafter described.

The nonylphenol-formaldehyde-ethylene diamine condensation product is produced in the following manner: nonylphenol, formaldehyde (paraformaldehyde) and ethylene diamine in about equimolar amounts are admixed in a suitable aliphatic or aromatic organic solvent and heated to about 170 F. to 190 F. for about two to three hours, after which nitrogen is sparged into the reacted mixture to insure that essentially all the water is removed from the mixture. The product is believed to have the formula:

A typical long chain alkyl propioamido polyalkylene polyamine is produced in the following manner:

Polyisobutylene of about 950 molecular weight is dissolved in carbon tetrachloride or other suitable organic solvent and chlorine gas bubbled through it at ambient temperature for about four hours. After removal of the solvent, acrylic acid is heated with the chlorinated polyisobutylene to 450 F. for about 18 hours and the product recovered and purified. This polyisobutenyl propionic acid, with or without the use of a mineral lubricating oil (150 SUS viscosity at 100 F.) serving as a solvent or vehicle, is condensed with tetraethylene pentamine at about 300 F. for five hours; care being taken to see that more amino groups are present than the number of carboxylic acid groups so that the final product is a mixed amino-amide compound, i.e., the amide contains one or more free amino groups. This product may then be treated with a sulfur halide to produce the novel additives herein described. In place of using an acrylic acid or methacrylic acid as before stated, it is possible to employ benzoic acid and, in some instances, a naphthenic acid.

The sulfurization is effected with a sulfurizing agent which is a halide of sulfur, for example, sulfur dichloride, sulfur monochloride, sulfur dibromide, or sulfur monobromide. These are the most readily available halides of sulfur but any commercially available sulfur halide which will incorporate sulfur into the amino compound may be employed. In some instances, sulfonyl chloride is useful for this purpose.

The sulfurization reaction may be carried out in a light mineral lubricating oil as the vehicle or it may be carried out by simply heating the sulfur halide and the amino compound in the absence of any solvent. Other solvents which may be used involve such materials as heptane or hexane o lig t a phthas whi h a e mixtu e of norma and isoparaffins. The reaction, however, proceeds under relatively mild conditions, i.e., at temperatures of about F. to about 300 F. and is usually completed in 24 hours or less although longer periods of time may be employed, if desired. As before stated, the mole ratio of amino compound to sulfur halide may be between about 1:1 and about 1:5. With the milder reaction conditions, it is preferred to employ a mole ratio of amino compound to sulfur halide of about 1:1 and a temperature approaching 300 F. It is preferred to maintain a mole ratio of amino compound to the sulfur halide of between about 1:1 and about 1:2.

The exact mechanism of the reaction involved in treating the amines with sulfur halides is not fully understood; but it is believed that in some way the sulfur chemically combines with the nitrogen and forms a bridge involving one or more molecules of sulfur between the nitrogen and a carbon atom, especially an unsaturated carbon atom, of the same or a different molecule of amino compound. It may even be that a sulfur nitrogen ring, perhaps involving even more than one sulfur is somehow formed. It is not intended, however, that the present invention be limited in any manner to a theory of the mechanism or exact manner of linkage of the sulfur in the amine compound. It is believed, however, that the sulfur does chemically combine in some manner and that, by reason of this chemical combination, new compounds are formed having the desired attributes of improving lubricating oils, particularly those involved in heavy duty Diesel engine and gas engine service.

The lubricating oils to which the novel sul'furized amino compounds are added may be those derived from naphthenic, parafiinic, aromatic, or mixed crudes. They generally have viscosities at 210 F. of between about 45 and about SUS (Saybolt Universal seconds) and at F. of between about and about 1100 SUS. These oils have viscosity indices between about 0 and about 75. In the case of oils employed in high speed heavy duty Diesel engines, oils of relatively high viscosity index are often preferred, i.e., of the order of 75 or even higher but usually most Diesel engines employ lubricating oils having viscosities of between about 75 and about 80 SUS at 210 F. and of between about 800 and about 1250 SUS at 100 F., their viscosity indices ranging between about 55 and about 80.

The lubricating oil compositions of the present invention may also contain other additives in association with the herein described novel sulfurized amines. These additives generally complement and supplement the properties attainable through the use of the herein described novel additives. They are generally of the following types and are used in about equivalent amounts to the amounts of the novel additives employed. In each case, this amount ranges between about 0.05 and about 10 wt. percent based on the weight of the total lubricating oil composition. Typical supplemental additives are sulfurized polyisobutylene, phosphosulfurized polyisobutylene, phosphosulfurized condensation products of nonylphenol, formaldehyde, and ethylene diamine, sulfurized imides such as the polyisobutenyl succinimide of tetraethylene pentaamine wherein the sulfurizing agent can be elemental sulfur, sulfur monochloride, phosphorus pentasulfide, and the like, or more conventional oxidation inhibitors, corrosion inhibitors, and viscosity index improvers such as phenyl alpha-naphthylamine, sorbitan monooleate, and polyisobutylene, respectively. A pour point depressant such as wax alkylated naphthalene and a dispersant such as the metal salts of petroleum sulfonic acids may also be used.

A number of routine tests were carried out on the compounded oils containing the novel additives hereinbefore described in order to illustrate the beneficial effects of the novel additives. The following tests were performed:

(1) An oxidation stability test was used for a labor a. tory determination and measured the viscosity increase and the alkalinity retention of the compounded oils. This test involves heating the compounded oil to a temperature of about 340 F. in the presence of a copper-lead oxidation catalyst while intimately mixing the compounded oil with air. The viscosity increase (SUS, at 100 F.) after 23 hours and a determination of the percentage of viscosity increase is measured and indicates the tendency of the oil to oxidize in an engine. Levels below 25% increase are good.

(2) A copper-lead bearing weight loss, in milligrams, involving the compounded oil was also conducted. This test measures the weight loss of Cu-Pb bearings due to corrosion by the oil. Generally, levels below 100 indicate satisfactory anticorrosion of the types of bearings.

(3) A CRC-L-38 Engine test in which a single cylinder CLR engine is charged with the oil under test and run for 40 hours at high speed (3,150 r.p.m.), high temperature (190200 F an oil sump temperature of 275/290 F. and high load, for the purpose of determining, inter alia, the oxidation characteristics of the oil, Cu Pb bearing weight loss and corrosion.

(4) Gas engine detergency and cleanliness test.-This involves the testing of a compounded lubricating oil in a Chevrolet gas engine of 6 cylinders and of 216.5 cubic inch displacement operating on natural gas and having 21 horsepower rating of 34 at 1,500 r.p.m. The engine operated at 2.5% excess oxygen in the exhaust to maximize nitrogen fixation and oil degradation. This test was conducted for a period of 96 hours after which the pistons and cylinders of the engine were inspected for varnish and sludge and the Cu-Pb bearings were inspected for hearing weight loss in milligrams. A demerit rating system, overall, was averaged out after inspection and rating of the various portions of the engine, with 0 being recorded for a perfectly clean engine part and 10 being assigned to the very dirtiest engine parts and as having the worst possible varnish and sludge deposit formation.

The following examples are illustrative of the character and nature of the invention but it is not intended that the invention be limited thereby.

EXAMPLE 1 936 grams of a condensate of nonylphenol, formaldehyde, and ethylene diamine, prepared as previously described, was admixed with 200 grams of a phenol extracted parafiinic oil having a viscosity at 210 F. of 60 SUS and at 100 F. of 460 SUS as a medium or vehicle and with about 103 grams of sulfur dichloride. The temperature during the admixture rose to about 137 F. and thereafter the mixture was heated to 200 F. for 1 hour. It was then cooled and a 10% solution of sodium bicarbonate in water was added until effervescence stopped. Thereafter the water was evaporated 01f and the mixture was filtered through Dicalite (a diatomaceous earth sold by Dicalite Corporation). The resultant product contained 1.10% nitrogen and 2.70% sulfur as well as 0.2% chlorine.

EXAMPLE 2 The polyisobutylene propioamide of tetraethylene pentamine, prepared as previously described in the amount of 1,000 grams, was admixed with 103 grams of sulfur dichloride. During the admixture the temperature rose to 138 F. and thereafter the mixture was heated at 152 F. for 24 hours, cooled, and water and sodium bicarbonate added thereto. The water was evaporated off and the product filtered through diatomaceous earth. It had an analysis of 1.19% nitrogen, 3.16% sulfur, and 3.24% chlorine.

EXAMPLE 3 518 grams of nuclear-substituted polyisobutylene diphenyl amine, prepared by reacting polyisobutylene of 830 number average molecular weight, in the amount of 2,490 grams and 507 grams of diphenyl amine, under the following conditions: The admixture was heated to 230 F. in the presence of aluminum chloride for about 2 hours. Thereafter 10.5 grams of sodium was added and the temperature was raised to 360 F. and held there for 24 hours. The mixture was cooled and 50 cc. of water was added to decompose the excess and unreacted sodium and aluminum chloride. Thereafter, at 320 F., water was evaporated from the reacted mixture and the mixture then filtered through Dicalite. The reacted mixture together with 300 cc. of heptane had added thereto 67.5 grams of sulfur monochloride. The temperature rose slowly to 105 F. and was held there for 24 hours at the end of which time water and sodium bicarbonate were added. Thereafter, the water and heptane were evaporated off and the product was filtered through diatomaceous earth. It had an analysis of 0.43% nitrogen, 3.85% sulfur, and 0.71% chlorine.

EXAMPLE 4 Polyisobutylene nuclear-substituted diphenyl amine was prepared as described in the preceding example. 1,500 grams (88.1%) of this product were admixed with 202.5 grams (11.9%) of sulfur monochloride. The reaction was carried out in 500 cc. of normal heptane as a solvent at a temperature of F. and this temperature was held for about 24 hours. After neutralization with sodium bicarbonate and the removal of water, the final product was filtered through diatomaceous earth, recovered, and analyzed as follows: 0.78% nitrogen, 5.02% sulfur, and 0.23% chlorine.

EXAMPLE 5 1,765 grams of the same polyisobutenyl diphenyl amine as descirbed in Example 4 (89.7 wt. percent) and 202 grams of sulfur monochloride (10.3 wt. percent) in 500 cc. of heptane were maintained at a temperature of 100 F. for 24 hours at the end of which time the reacted mixture was treated with aqeuous sodium bicarbonate and water and heptane distilled off. After filtering through diatomaceous earth, the recovered product analyzed 0.72% nitrogen, 3.91% sulfur, and 0.25% chlorine.

A series of tests were carried out using a base lubricating oil containing 5 wt. percent of each of the additives described in Examples 1 through 5. The base oil was a phenol extracted parafiinic oil having a viscosity at 210 F. of 60 SUS and at 100 F. of 460 SUS. The tests shown in the following table and theirmanner of being carried out are described hereinbefore.

TABLE Fercent Gas engine vlscosity overall increase Gu-Pb bear- L-38 demerit, Base oil plus sulfurized Wt. percent at 100 F.. ing weight engine BWL, after 96 amine additive 23 hrs. loss, mg. mg. hours 1 Base oil alone .t 51 285.0 1, 000 0. 63 Base oil plus Example 1.. 5. 0 20. 0 1 +2. 3 Base oil plus Example 2.. 5.0 26. 7 Base oil plus Example 3-- 5.0 17. 2 Base oil plus Example 4-- 5.0 20. 0 Base oil plus Example 5 3.0 11. 8

1 0 denotes extremely clean engine, 10 denotes extremely dirty engine. 9 Contained also 2% of polyisobutenyl propioamide of tetraethyleue pentamine.

From the above data it is readily apparant that the sulfur halide treated amines are outstanding in providing oxidation stability, inhibition of Cu-Pb corrosion, dispersancy, and general engine cleanliness. The addition of a conventional dispersant, such as polyisobutenyl propioamide of tetraethylene pentamine to the polyisobutenyl diphenylamine treated with S Cl (Example 5) improves performance in the gas engine while maintaining high levels of performance in all other areas. In fact, this combination shows better oxidation stability (percent viscosity increase) than the sulfurized material Without dispersant (the dispersant alone is very poor in oxidation inhibition).

Having described the general nature and embodiments of this invention, the true scope is now particularly pointed out in the appended claims.

What is claimed is:

1'. A lubricating oil composition comprising a major amount of a mineral lubricating oil and between about 0.05 and about 10.0 wt. percent of a sulfurized ashless dispersant prepared by reacting a primary or secondary aryl amine selected from the group consisting of C-alkyl phenylene diamines, C-alkyl diphenyl amine, C-alkyl N-phenyl phenylene diamines, C-alkyl aniline, C-alkyl toluidines and C-alkyl xylidines, wherein the alkyl group is attached to a benzene nucleus and contains from 40 to 250 carbon atoms, with a halide of sulfur, wherein the sulfurization is carried out at a temperature between about 80 and about 300 F. for between about 30 minutes and about 24 hours.

2. A lubricating oil composition as in claim 1 wherein the amine is a C-alkyl diphenyl amine.

3. A lubricating oil composition as in claim 2 wherein the amine is C-polyisobutenyl substituted diphenyl amine.

4. A lubricating oil composition as in claim 1 wherein the halide of sulfur is sulfur dichloride.

5. A lubricating oil composition as in claim 1 wherein the halide of sulfur is sulfur monochloride.

6. A lubricating oil composition as in claim 3 wherein the halide of sulfur is sulfur monochloride.

7. A lubricating oil composition as in claim 3 wherein the composition also contains the polyisobutenyl propioamide of tetraethylenepentamine.

References Cited UNITED STATES PATENTS 2,781,318 2/1957 Cyphers 25247 2,209,976 8/1940 James 25247 2,295,074 9/1942 Britton et a1. 260243 2,348,044 5/1944 Whittier et a1. 25247 XR 2,459,114 1/1949 Oberright 25242.7 3,156,728 11/1964 Orlofi' et a1. 25247 XR DANIEL E. WYMAN, Primary Examiner.

W. CANNON, Assistant Examiner.

US. Cl. X.R.