US3468798A - Ashless dispersant-inhibitors and petroleum hydrocarbons containing the same - Google Patents

Description

United States Patent 3,468,798 ASHLESS DlSPERSANT-INHIBITORS AND PE- TROLEUM HYDROCARBONS CONTAINING THE SAME Jerome Panzer, Roselle Park, Union, N.J., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Sept. 26, 1966, Ser. No. 581,685 Int. Cl. Cm 3/32; C101 J/24 US. Cl. 25247 7 Claims ABSTRACT OF THE DISCLOSURE Ashless dispersants, for normally liquid hydrocarbons, are novel thiazines of the formula:

R 111 A/ \B The present invention relates to improvements in the production of oil-soluble nitrogen and sulfur-containing additives for petroleum hydrocarbon compositions such as fuel oils, heating oils, and lubricating oils. More particularly, the invention relates to lubricating oil compositions containing minor amounts of novel sulfur and nitrogen-containing compounds which are aryl thiazines and which are particularly useful in lubricants involved in heavy duty operation such as gas engines and railroad diesel engines.

Numerous addition agents have been prepared and used in heavy fuels and lubricants to improve oxidation stability, dispersancy, freedom from the formation of insoluble materials, protection from rust and corrosion, and the like. Good oxidation stability, good dispersancy and detergency have become essential requirements for such lubricants when employed in heavy duty operations. By dispersancy is meant the prevention of the deposition of insoluble material and by detergency is meant the quality of removing deposits from engine parts after they have been formed and deposited on those parts. In the field of railroad diesel engine lubrication and gas engine lubrication, the criteria that must be met by the lubricants include high oxidation stability and the retention of viscosity during use. Satisfactory protection from Wear and from rust and corrosion is also, of course, desirable. Additives for heating oils must supply acceptable oxidation stability and freedom from sludge formation. Additionally, in heavy duty operations involving railroad diesel engines and gas engines, the choice of a proper additive for the oils used therein is particularly difficult because of the presence of sliver-containing bearings and copperlead-containing bearings; these types of bearings being unusually highly susceptible to wear and corrosion. The utility of an additive for lubricating oils in such systems will accordingly depend, in part, upon its capacity of providing acceptable limits for silver and/or copper-lead corrosiveness. There is a constant demand for lubricants of increased oxidation stability which will exhibit viscosity stability, resist oxidation, and, at the same time, satisfy Patented Sept. 23, 1969 ice the stringent requirements for engine cleanliness, wear reduction, and corrosion protection.

In the prior art, various additives have been described for use in lubricating compositions for the above mentioned types of internal combustion engines. One particular class of additives includes the alkaline earth metal salts of amino alkylated phenols. Such additives are described in US. Patent 2,353,491 as salts of the reaction products obtained by condensing an aliphatic aldehyde and an aliphatic polyamine with an alkyl-substituted phenol compound. Also, US. Patent 3,036,003 discloses the use of such reaction products in conjunction with petroleum sulfonates to impart cleanliness and stability to lubricating oils for internal combustion engines. Other patents such as US. Patents 3,018,247, 3,018,250, and 3,018,291 disclose the nitrogen-containing derivatives of high molecular weight alkenyl succinic anhydrides as being useful in lubricating oils for the reason that those additives therein disclosed have excellent sludge dispersancy properties. Additionally, US. Patent 2,781,318 discloses additives for lubricating oils for internal combustion engines which additives are said to impart effective detergency properties to those oils. These compounds are specifically shown to be alkyl-substituted phenothiazines, wherein the alkyl group on each benzene nucleus contains from 4 to 16 carbon atoms, preferably from 6 to 12 carbon atoms. It is shown, however, in that patent in column 3, lines 1-33, that where as much as 2% of dioctyl phenothiazine is incorporated into a lubricating base oil stock of midcontinent origin, a slight sediment was produced upon allowing the compounded composition to stand for seven days at room temperature. It is apparent that such additives, as disclosed in this patent, have a limited solubility. In many instances it is desirable to add as much as 5% or even 10% of the particular additive to the lubricating oil in order to achieve the desired properties in the oil particularly so where the oil is to be employed under extremely heavy duty conditions such as those encountered in the operation of gas engines and railroad diesel engines. Dioctyl phenothiazine, because of its limited solubility, cannot satisfy this requirement.

It has now been discovered that ashless dispersantsoxidation inhibitor type additives of the alkyl phenothiazine series wherein an alkyl group is attached to one of the aromatic nuclei or to the nitrogen of the compound and contains from between about 40 and about 250 carbon atoms, affords vastly improved properties to those lubricating oils. The novel phenothiazines hereinafter more specifically described are vastly improved as to their effectiveness because of their vast improvement in oil solubility. It is not necessary that all aromatic nuclei of the aryl thiazine contain these long chain alkyl groups. In fact, equally effective additives are produced wherein the long chain alkyl group is directly attached to the nitrogen atom of the thiazone ring.

The novel thiazines may be represented by the following general formula:

wherein R is selected from the group consisting of hydrogen, C -C alkenyl and C -C alkyl, wherein A and B are each selected from the group consisting of a benzene ring, a naphthalene ring, an R substituted benzene ring, an R substituted naphthalene ring, an RNH substituted benzene ring, an RNH substituted naphthalene ring, wherein said N and S are each attached to ad jacent carbon atoms of A and B, at least one R being said 3 alkenyl or said alkyl and R being hydrogen or a phenyl radical.

These novel thiazines are prepared by the reaction of the corresponding diaryl secondary amines, alkylated with a mono-olefin having the required number of carbon atoms in the presence of the conventionally employed alkylation catalysts, i.e., BF aluminum chloride, or any other Friedel-Crafts type catalyst. This produces a secondary amine containing the long chain alkyl group on one of the aromatic nuclei. The thiazine is then formed in conventional manner through the use of elemental sulfur and iodine as a catalyst under conditions such as those described in Example 1 of U.S. Patent 2,781,318, to produce the corresponding alkyl pheno or alkyl naphtho thiazine. Also, this product may be further reacted with the chloride of the same or a dilTerent mono-olefin to produce a di alkyl, one C-substituted and one N-substituted, aryl thiazine.

Additionally, it is possible to convert, by conventional means the long chain mono-olefin into the corresponding long chain alkyl chloride or other halide and this, in turn, may then be converted into the corresponding N-substituted long chain alkyl derivative of the particular thiazine employed by means of the reaction described by F. D. Hager, Organic Synthesis, collective volume 1, page 544 (1941). The long chain mono-olefin, i.e., C alpha olefin, is converted to the alkyl chloride by treating it in carbon tetrachloride solution with chlorine gas at 75 F. to 250 F. until the equimolar amount of chlorine has been incorporated thereinto, usually from 2 to 4 hours. This product is then reacted with the desired or selected thiazine and anhydrous K CO at 200450 F. to form the N-alkyl substituted phenothiazine, the HCl formed being eliminated by reaction with the K CO The methods by which the carbon-substituted alkyl aryl thiazines and the N-substituted alkyl aryl thiazines are produced are conventional well known reactions and, except insofar as they are employed to produce the novel thiazines herein disclosed, do not form a part of this invention. The reaction conditions are well known. The alkylation of diaryl amines is found in many places in the literature. See R. Stroh et al., Newer Methods of Preparative Organic Chemistry, volume H, beginning at page 227 (1963), edited by W. Foerst. The production of the novel thiazines and, of course, their use in petroleum hydrocarbon mixtures does involve the use of novel reactants in that the use of the long chain mono-olefins or their corresponding halides derived therefrom have not been used in the preparation of the substituted aryl thiazines. Many of the specific mono-olefins which are on the market today may be employed in producing these novel thiazines, for example, polyisobutylene of a number average molecular weight ranging between about 500 and about 1,200 may be employed. This is an article of commerce readily available on the market. Other olefinically unsaturated materials of similar molecular weights and having the above specified number of carbon atoms per molecule may be employed such as, for example, polypropylene, polyethylene, the copolymers of ethylene and propylene, the copolymers of ethylene and isobutylene and the like, provided the conditions of polymerization or copolymerization are so controlled and the final treatment of the reaction product is so carried out that the product produced or the fraction recovered from the reacted product has the required number of carbon atoms, i.e., from to 250 carbon atoms, as heretofore specified.

In the production of the carbon-substituted long chain alkyl aryl thiazines, the diaryl amine may be selected from any one of a number of such amines, for example, diphenyl amine, dialpha naphthyl amine, dibeta naphthyl amine, phenyl alpha naphthyl amine, phenyl beta naphthyl amine, ditolyl amine, tolyl alpha naphthyl amine, tolyl beta naphthyl amine, N-phenyl-p-phenylene diamine, o, m, and p-amino diphenyl amines (i.e., N-phenyl-pphenylene diamine), and the closely related, simple, sub- 4 stituted monoand di-nuclear, secondary, aromatic amines.

In general, the reactions are carried out under conventional conditions as heretofore stated. These involve, in the case of the use of sulfur plus iodine catalyst, a temperature of 340 F. to 450 F. with or without the use of a hydrocarbon solvent such as hexane, benzene, or light naptha for a period of time ranging between about 1 hr. and about 24 hrs. After the completion of the reaction, the product is usually filtered through Dicalite, which is a diatomaceous earth sold by Dicalite Corporation, or it may be filtered through glass wool, another diatomaceous earth, or any other suitable filtering agent in order to remove the impurities from the final product, after which the thiazine product is recovered from its solvent.

In general, between about 0.1 and about 10 wt. percent of the particular novel thiazine is employed in the middle distillates or the lubricating oil fractions which are customarily employed for heavy duty operation in railroad diesel engines and gas engines. Preferably between about 0.3 and about 6 Wt. percent of the material is employed in the final lubricating oil contained in the engine. If convenient, however, oil concentrates containing the novel additives are prepared and from a commercial and practical standpoint they are usually desirable methods of marketing the additive. Such oil concentrates will generally contain from 30% up to 70% of the novel thiazine additive; this being readily accomplished because of the high degree of solubility of the additive in the oil, something that could not be accomplished in connection with the dioctyl phenothiazine additive described in US. Patent 2,781,318.

The final lubricating composition employed in the engines should have a sufficient but minor amount, in all cases, of the novel additive in order to improve the oxidation stability of the oil. When this amount has been employed it has been found that there is a minimum of bearing corrosion and a minimum of bearing wear as will be seen from the following examples.

The lubricating oil is preferably a mineral lubricating oil and may be derived from naphthenic, paraffinic, aromatic, or mixed crudes. It will generally have a Saybolt viscosity at 210 F. of between about 45 and about 90 seconds and at 100 F. a viscosity of between about and about 2,200 seconds. Its viscosity index is generally between about 0 and about 75. In the case of oils employed in high speed diesel engines, oils of high viscosity index are often preferred, i.e., of the order of 75 or higher, but generally, most diesel engines employ lubricating oils having viscosities at 210 F. of between about 45 and SUS and at F. of between about and about 1,100 SUS, with 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 alkyl substituted aryl thiazines. These other additives may also be employed in amounts ranging between about 0.1 and about 10 wt. percent, based on the total composition. They may be conventional oxidation inhibitors, corrosion inhibitors, viscosity index (V.I.) improvers, anti-wear agents, pour point depressants, thickeners, dyes, and the like.

A typical example of a conventional oxidation inhibitor employed is phenyl alpha naphthylamine.

A typical example of a conventionally employed corrosion inhibitor is sorbitan mono-oleate.

Typical examples of conventionally employed viscosity index improvers are polyisobutylene and polymers of alkyl methacrylates.

A typical example of a conventionally employed antiwear agent is a zinc salt of a mixture of dialkyl dithiophosphoric acids prepared by reacting a mixture of isobutanol and mixed amyl alcohols with P 8 and converting this to the zinc salts by reaction with ZnO.

A typical example of the conventionally employed pour point depressant is wax alkylated naphthalene.

Typical detergents are metal salts of alkyl phenol thioethers and metal salts of petroleum sulfonic acids, etc.

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

(1) Oxidation stability test was used for a laboratory determination of the viscosity increase and the alkalinity retention of the compounded oils. The test involves heating the recovered oil composition 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 weightloss in milligrams involving the novel oil composition was also undertaken. This test measures the weight loss of the Cu-Pb bearings due to corrosion by the oil. Generally, levels below 100 indicate satisfactory anti-corrosion of these types of bearings.

(3) An EMD Silver Corrosion test is a standard test and was run to determine the corrosiveness of the novel lubricant composition toward the silver bearings which are commonly used in railroad locomotive diesel engines. This test involved heating the lubricating oil to 285 F. for 72 hours with mild stirring in the presence of a section of a silver bearing and a copper strip and determining the weight loss in milligrams after 72 hours of such stirring and heating. Under those conditions, an acceptable oil for railroad diesel engines gives less than 3 mg. of weight change. A greater weight change may still render an oil acceptable for gas engines, however, because they usually do not employ silver or silver alloy bearings.

(4) 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 rpm), high temperature (190200 F.), 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.

(5) Gas engine detergency and cleanliness test.This involves the testing of the lubricating oil compositions in a 6-cylinder Chevrolet gas engine of 216.5 cubic inch displacement operating on natural gas and having a horse power rating of 34 at 1,500 rpm. The engine operated at 2.5% excess oxygen in the exhaust to maximize nitrogen fixation and oil degradation. The test was carried out for a period of 96 hours after which the pistons and cylinders of the engine were inspected for varnish and sludge, the hearings were inspected (for bearing weight loss, in milligrams) and the copper-lead bearings in the engine were checked for bearing weight loss, in milligrams. A demerit rating system, overall, averaged out various portions of the engine, with 0 being recorded for a perfectly clean engine part and 10 being assigned to the very dirtiest engine part or the worst possible varnish 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 1 830 grams of polyisobutylene (number average molec ular weight of 830) was admixed with 169 grams of diphenyl amine and 10 grams of aluminum chloride. The reaction vessel was maintained under a nitrogen atmosphere and was heated to 230 F. 3.5 grams of metallic sodium were added and the temperature was then raised to 360 F. and held under that temperature condition for 24 hours. Thereafter the mixture was cooled and enough water was added to the reacted mixture to decompose any sodium and aluminum salts remaining. Thereafter the water was evaporated by heating the treated reacted mixture to a temperature of 320 F. The mixture was then filtered through Dicalite and gave a polyisobutyl nuclear alkylated diphenyl amine containing between about 1.32% and about 1.40% nitrogen.

EXAMPLE 2 The product of Example 1 in the amount of 518 grams was admixed with 16 grams of sulfur and 6 grams of iodine. It was heated at 360 F. for 24 hours after which the reacted mixture was filtered through Dicalite. The resultant alkylated phenothiazine contained 0.66% nitrogen and 0.95% sulfur.

EXAMPLE 3 A mixture of 690 grams of chlorinated polyisobutylene (3.3% chlorine) of a number average molecular weight of about 830, 88 grams of phenothiazine, and 70 grams of anhydrous potassium carbonate was heated to about 350 F. and held for 24 hours, then filtered through Dicalite. The resultant N-substituted polyisobutenyl phenothiazine contained 0.66% nitrogen and 1.67% sulfur.

EXAMPLE 5 219 grams (22.4%) of N-phenyl beta naphthyl amine was admixed with 690 grams (70.1%) of chlorinated polyisobutylene, the material used in Example 4, admixed with sulfur in the amount of 64 grams (6.5%) and iodine in the amount of 10 grams (1.0%) and in a single step process was heated for 24 hours at a temperature of 300 F. Thereafter, the reaction product was filtered through diatomaceous earth (Dicalite). The resulting product is believed to have the formula:

Polyisobutyl l N {11 1) and/or Possibly another polyisobutyl derivative was also formed but this has not been determined with certainty. The resulting product contained 0.94% nitrogen and 2.27% sulfur.

Polyisobutyl EXAMPLE 6 500 grams (97%) of polyisobutyl nuclear alkylated diphenyl amine was admixed with 16 grams (2.9%) of sulfur and 0.5 gram (0.1%) of iodine. This was reacted at a temperature of 350 F. for 24 hours substantially in the same manner as described in Example 2, followed by filtering through Dicalite. The resulting product contained 0.63% nitrogen and 0.80% sulfur.

Each of the thiazines obtained in Examples 2 through 6, as above described, were tested in lubricating oil bases suitable for use in gas engines and railroad diesel engines. In all cases, 5 wt. percent of the active thiazine was incorporated into the base lubricating oil and tested. In Examples 2, 3, 4 and 6, the base lubricating oil A was a phenol extracted parafiinic oil with a viscosity at 210 F. of 60 SUS and at 100 F. of 460 SUS.

In the case of Example 5, the base oil B was a hydrofined, clay contacted naphthenic stock With a viscosity at 210 F. of 65 SUS and at 100 F. of 650 SUS.

EXAMPLE 7 701 parts by weight of polyisobutyl chloride (material used in Example 4), 65 parts of sulfur, 10 parts of iodine, and 224 parts of phenyl alpha naphthylamine were heated at 300 F. for 24 hours followed by filtration through Dicalite. Analysis showed a nitrogen content of 0.84% and a sulfur content of 2.26%.

EXAMPLE 8 598 parts of polyisobutyl chloride, 55 parts of sulfur, 159 parts of N-phenyl-para-phenylene diamine, 8 parts of iodine, 182 parts of base oil A were heated at 350 F. for 24 hours and then filtered through Dicalite. The product had 0.84% nitrogen and 3.23% sulfur.

wherein R is selected from the group consisting of hydrogen, -0 alkenyl and C C alkyl, wherein A and B are each selected from the group consisting of a benzene ring, a naphthalene ring, an R substituted TABLE I Percent Cu-Pb EMD L-38 Engine Viscosity Bearing Silver Bearing Increase Weight Corro- Weight Run No. Oil Composition plus Additive at 100 F. Loss, Mg. sion, Mg. Loss, Mg.

Base Oil A. 51. 0 285 3.0 1, 000 2 Base Oil B 53.0 149 8. 6 1, 000 Base Oil A Plus Example 2 l3. 5 42 2. 1 4- Base Oil A Plus 5% Example 3.- 13. 2 48 2. 4 49 5- Base Oil A Plus 5% Example 4 17. 5 45 2. 3 62. 7 6. Base Oil B Plus 5% Example 5-. 14.0 23 2. 8 20. 9 7. Base Oil A Plus 5% Example 6 12. 1 34 2. 4 8 Base Oil A Plus 5% Example 1 17. 8 19 5. 7 107 9. Base Oil A Plus 3% Example 4 Plus 2% PIBA/TEPA l8. 1 88 10 Base Oil A Plus 5% Example 7 25. 0 24 3.2 11 Base Oil A Plus 4% Example 7 Plus 1.3% PIBSA/TEPA 12. 7 8 1. 6 18 12 Base Oil A Plus 5% Example 8 12. 5 27 11. 1

1 Dispersant made by first reacting polyisobutylene chloride with acrylic acid and then reacting three mols of this product with one mol of tetraethylene peutamine.

2 Made by reacting polyisobutenyl succinic anhydride with tetraethylene pentarnine. Gas engine tests were also carried out using the benzene ring, an R substituted naphthalene ring, an

various additives in the same base oils and also using compounded or mixed additives in the base oils. The demerit ratings, 0 for perfect cleanliness and 10 for the very dirtiest parts, reflect the combined functions of degree of oxidation, inhibition and dispersancy. An oil containing no additives, but which is highly refined, will generally give overall demerit ratings greater than 0.5; a moderately good oil will give values (demerit) in the range of 0.2 to 0.3. Outstanding compounded oils will show overall demerit ratings below 0.12. The viscosity increases of the used oils as shown in Table II are also quite acceptable.

RNH substituted benzene ring, an RNH substituted naphthalene ring, wherein said N and S are each at tached to adjacent carbon atoms of A and B, at least one R being said alkenyl or said alkyl, R being hydrogen or a phenyl radical.

2. Liquid petroleum hydrocarbons containing an ashless dispersant as in claim 1 wherein one R is polyisobutyl and A and B are benzene rings.

3. Lubricating oil compositions containing up to about 10 wt. percent of an ashless dispersant as defined in claim 1.

4. Lubricating oil compositions containing up to about TABLE II.GAS ENGINE TEST DATA [Demerit Rating (0 to 10)] Percent Piston Viscosity Overall Skirt Ring Ring Increase Run N0. Oil Composltion Plus Additive (Average) Varnish Zone Sticking (Used oil) 13 Base Oil A 0. 63 0.26 0. 29 0. 02 100 Base Oil A Plus 5% Example 3 0. 19 0.17 0.32 0.28 19 Base Oil A Plus 5% Example 4 0.21 0. 48 0. 33 0. 14

Base Oil A Plus 3% Example 4 Plus 2% PIBA/TEIA 0. 11 Nil 0. 05 0. 1 1

Base Oil B Plus 14.5% Commercial Additive A. 0.08 O. 12 0.06 N11 78 18 Commercial Oil Plus Dispersant 2 0. 10 0. 13 0. l0 Nil 24 2 Commercially available ashless additive in oil base.

Table I shows the various results of tests obtained by using the various novel additives in lube oil base stocks customarily employed in railroad diesel oils and gas engine oils. Runs 1 and 2 show the adverse results obtained using the uncompounded base stocks. Run 8 shows the adverse results obtained using the polyisobutenyl nuclear alkylated secondary aryl amine as an additive. Examples 3 through 7 and 9 through 12 show the improved results achieved in using the novel phenothiazine additives as the sole additives or in using these novel compounds in conjunction with conventional dispersants as the additives to the base stocks. The test results show that these additives provided improved lube oils as to oxidation inhibition characteristics, as to bearing weight loss, and as to corrosion properties. Table II likewise shows results wherein the compounded oils were far 10 wt. percent of an ashless dispersant as defined in claim 2.

5. Lubricating oil compositions containing up to about 10 wt. percent of an ashless dispersant as defined in claim 1 wherein one R is polyisobutyl and the other R is hydrogen and wherein the thiazine is phenothiazine.

6. Lubricating oil compositions containing up to about 10 wt. percent of an ashless dispersant as defined in claim 1 wherein R is polyisobutyl attached to the thiazine nitrogen and A and B are benzene rings.

7. Lubricating oil compositions containing up to about 10 wt. percent of an ashless dispersant as defined in claim 1 wherein R is polyisobutyl attached to the thiazine nitrogen and A and B are benzene rings one of which rings has attached thereto a phenylamino radical.

(References on following page) 9 10 References Cited Phenothiazine Type preprints of the petroleum section UNITED STATES PATENTS of the Am. Chem. Society, vol. 1, No. 4, September 1956, pp. 102-114. 2,528,785 11/1950 Rlchter et a1. 252-47 2,781,318 2/ 1957 Cyphers 25247 DANIEL E. WYMAN, Primary Examiner 2,516,914 8/1950 Revukas 25256 5 3 233,7 4 11 195 ()such 252 57 CANNON, Asslstant EXamlHer 3,306,852 2/1967 Hendrickson 25251.5 XR Us l X 3,325,567 6/1967 Le Suer 252-499 XR OTHER REFERENCES 10 44 63 260 243 Cole et a1.: Antioxidant Mechanism Studies of the