US3373117A - Lubricants containing chloroanilinephosphate salts - Google Patents

Description

United States Patent G 3,373,117 LUBRICANTS CONTAINING CHLGROANILINE- PHOSPHATE SALTS Earl Eugene Sommers, Graylyn Crest, Wilmington, Del.,

assignor to E. I. du Pont de Nemours and Company,

Wilmington, Del., a corporation of Delaware No Drawing Filed Dec. 17, 1965, Ser. No. 514,711

3 Claims. (Cl. 252-325) ABSTRACT OF THE DESCLOSURE Salts of aromatic chloroamines and C C alkyl acid phosphates as extreme pressure additives for conventional lubricating oils and break-in lubricating oils.

Background of the invention This invention is directed to natural and synthetic lubricating oils having significantly improved antiwear and load carrying ability. These lubricants have incorporated therein a chlorinated aromatic amine salt of an alkyl acid phosphate.

The need for special lubricant compositions for use in machinery subjected to extreme pressures has long been recognized and is continuing due to constant changes in automotive and industrial equipment. The tendency to reduce the size of power transmitting devices together with increases in engine power have raised the pressures between bearing surfaces so that lubricants having increased load carrying ability are required. Various compounds have been added to lubricants to improve their extreme pressure properties. The use of compounds of chloride, sulfur and/or phosphorus is well known.

Certain organic compounds including some or all of these elements are effective extreme pressure additives. Chlorine containing lubricants are desirable for the reason that under high stress a thin lubricating film is formed, believed to be a metal chloride, between the metal parts. However, incorporation of chlorine into the additive introduces a problem of corrosion, due to the breakdown of the additive under high stress and accompanying increase in temperature, resulting in the formation of corrosive chlorine containing compounds.

Description of the invention It is, therefore, an object of this invention to provide a novel lubricant capable of withstanding high contact pressures under severe and adverse operating conditions. It is a further object to provide such a lubricant composition which does not decompose under high stress and increased temperatures to form corrosive compounds, but on the contrary, has intrinsic antirust activity.

These and other objects of the invention will be apparent from the following description and claims.

The present invention is based on the discovery that certain chloroamine salts of acid phosphates have the ability to confer extreme pressure properties to natural and synthetic lubricating oils; said salts do not decompose to form harmful corrosive materials during operation under heavy loads.

The lubricants of the present invention are especially adapted for use in internal combustion engines, industrial gear elements, hydraulically activated systems and similar machinery. These lubricants show improved antirust and antiwear properties. In addition, they have the advantage of being ashless.

More specifically, the present invention is directed to a lubricant composition having improved antiwear and load carrying ability comprising essentially a natural or synthetic lubricating oil and 0.05 to 2.0% by weight of the oil of a salt of an aromatic chloroamine and a (I -C alkyl acid phosphate.

Patented Mar. 12, 1968 The primary alkyl acid esters of orthophosphoric acid (acid phosphates) which are utilized in the practice of this invention are those esters in which only one or two of the three acidic hydrogen atoms of orthophosphoric acid have been replaced by the alkyl groups, e.g., the monoalkyl dihydrogen phosphates and the dialkyl hydrogen phosphates. Such esters may be obtained according to the general methods of the art which involve reacting an alcohol with phosphorous pentoxide (P 0 From about two to about four moles of the alcohol may be used per mole of P 0 Preferably, about three moles of the alcohol per mole of P 0 will be used to yield approximately equimolar mixtures of the mono and dialkyl esters of orthophosphoric acid, containing about 40 to about 60 mole percent of the monoalkyl esters and about 60 to about 40 mole percent of the dialkyl esters. These mixtures of monoand dialkyl esters are preferred for reasons of economy, but other mixtures, as well as the single monoalkyl esters and single dialkyl esters, may also be used.

For the preparation of these primary alkyl acid phosphates, the alcohol is a branched or straight chain primary alkanol having 8 to 18 carbon atoms or a mixture of two or more straight chain or two or more branched chain alkanols. The branched chain alkanols preferably are those made by the well known oxo process from C0, H and a branched chain olefin such as the C C monoolefinic polymers and interpolymers of propylene and butylene, as described for example in U.S. Patent 2,824,- 836, and in U.S. Patent 2,884,379. Examples of preferred oxo-alcohols that may be used are isooctyl alcohol from the propylene-butylene dimer, branched tridecyl primary alcohols from triisobutylene and from tetrapropylene, and the branched hexadecyl primary alcohols trom pentapropylene. Other branched chain primary alkanols that can be used are those that may be prepared by alkaline condensation of two primary alkanols, having the structure RCH CH OH wherein R is alkyl and totaling two to six carbon atoms, to produce branched primary alkanols that are branched in the 2-position, i.e.

RCH CH CHRCH OH For example, 2-hexyldecanol-1 is produced by heating n-octanol with caustic and zinc dust, and similarly, 2- ethylhexanol-l from butanol-l, as described in U.S. Patent 2,457,866. Other alcohols, that may be prepared by the latter and other methods known in the art and used to prepare phosphates according to the present invention, are of the formula RCH CH CHRCH OH where R is the same or different alkyl group, each having from two to six carbon atoms. The branched alcohols may also be prepared by the conventional aldolization of suitable aldehydes followed by hydrogenation. In this way, the well known oxo-octaldehyde, which is obtained from heptene-l, CO and H and which is a mixture consisting very largely of dimethylhexaldehydes, ethylhexaldehydes, and methylheptaldehydes containing the grouping is converted into Z-hexyldecanol, R'CI-IRCH OH, where R stands for C alkyl groups, such as dimethylbutyl, methylpentyl and ethylbutyl, and R stands for C alkyl groups such as dimethylhexyl, ethylhexyl and trirnethylpentyl groups. The straight chain primary alkanols are readily available on the market. Examples of such alcohols are octanol, nonanol, decanol, dodecanol, tridecanol, tetradecanol, hexadecanol and octadecanol.

Preferred phosphates are di(2 -ethylhexyl)hydrogen phosphate, the mixed monoand diisooctyl acid phosphates and mixed monoand di- C to C alkyl acid phosphates. The alkyl radicals of the last named phosphate stem from a mixture of alkanols of average molecular weight range of 150-155, derived from coconut oil. Hereinattcr this phosphate will be referred to as the C to C n-alkyl acid phosphate.

The amines used to prepare the salts are the readily available mono and di-chloro substituted aniline and monochloro substituted toluidine. Examples of such amines are mand p-chloroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline, 3-chloro-o-toluidine and S-chloro-o toluidine.

The preferred amines are o-chloroaniline and 3,4-dichloroaniline; The term aromatic chloroamine as utilized herein includes both chloroanilines and chlorotoluidines.

The amine salts of the present invention may be prepared according to any of the methods of the art, by neutraliZing the alkyl acid phosphate with the amine. Normally one mole of amine is used for one mole of dialkyl hydrogen phosphate, and two moles of amine for one moleof monoalkyldihydrogen phosphate. To produce a salt exerting a substantially neutral pH (5-7), about 1.5 moles of amine are required per mole of mixed monoand dialkyl phosphates.

A representative example of the preparation of the salt follows:

EXAMPLE I 53.2 parts (0.2 mol) of mixed to 60%) monoand (60 to 40%) di-isooctyl acid phosphate and 38.5 parts (0.3 mol) of o-chloroaniline were mixed and heated for one hour at 80 C., then cooled. The resulting product had a total acid number (TAN) of 179.

The additives of the invention may be used with a natural or synthetic lubricating oil. The natural oil may be mineral or vegetable in origin. The mineral oils may be paraifinic, naphthenic or aromatic in nature or a mixture thereof. Examples of such oils are internal combustion englue crankcase oils, gear oils, turbine oils, hydraulic fluids, industrial oils and lubricants. Suitable vegetable oils castoroil and similar oils.

The synthetic lubricating oils which are also improved are higher molecular Weight dicarboxylic acid esters, such as thealiphatic diesters of sebacic, adipic, azelaic, pyromellitic, trimelliiic and phthalic acids.

The amount of chloroamine phosphate salt to be added to the lubricating oil base stock is within the range of 0.05 to 2.0 weight percent based on Weight of the base oil. The preferred amount is 0.25 to 0.5 weight percent. This amount is effective in markedly improving the extreme pressure'and antiwear characteristics of the oil.

The following tests, A through E, illustrate the effectiveness of the chloroamine phosphate salt additive in mineral and synthetic oil.

A. Rapid Fau'ex test procedure The Falex test is described in Lubricant Testing by E. G. Ellis, Scientific Publications, Great Britain, 1953, pp. 150-153. The Falex tester consists of a motor driven vertical shaft to which is attached the test pin, which runs between two V-shaped bearing blocks. The tests were conducted for a two-minute wear-in period at 250 pounds jaw load. The eccentric arm was engaged and the jaw load automatically increased to the point of failure. Failure was a result of pin shearing or journal wearthrough.

The Falex test pieces were cleaned just before use by soaking at least 15 minutes in naphtha and then in acetone and finally wiping dry with clean cheesecloth. At this point, considerable care must be exercised in order to avoid touching the clean test pieces with contaminated rags, paper, or the fingers. lust prior to inserting the test pieces in the test machine they were examined visually for any obvious surface defects. Any detect was cause for rejection of the test piece.

After the test pieces were inserted in the test apparatus, the loading gear assembly Was attached to the lever arms.

The sample holder, containing about ml. of the test fluid, was placed in position and the test pieces immersed in the lubricant. Then the load on the bushing-journal couple was manually adjusted to 250 pounds (jaw load).

The machine was then run for two minutes at this jaw PHATES AS EXTREME-P RESSURE ADDITIVES IN ESTER- LUB RIOANI (DI-OXO-TRIDEOYL ADIPATE) Maximum Falex Seizure Test Bushing Seizure Torque at Temp, Load, lb. Seizure, F.

lb/in.

Additives 1 (Base Oil Only) 2, 250 48 Amine Salt of Isooctyl Acid Phosphate: 2

o-Chloro aniline i 3, 625 46 262 m-Ohloroaniline 3, 200 45 27 5 p-Chloroaniline 3, 750 42 252 2,4-dichloroaniline i 3, 250 42 227 3,4-dlchloroaniline 3, 300 46 205 3-chloro-o-toluidine 3, 450 45 242 fi-chloro-o-toluidine 3, 725 46 255 Iscoctyl Acid Phosphate 2 only 2, 350 36 230 Arnlne Saltot 83-01 n-Alkyl Acid Phosphate: 2

o-Chloroaniline 4, 500 44 272 3-chl0ro-o-toluidlne- 4, 500 45 2 30 3,4-diohloroaniline i 4, 500 46 260 Cs-Grs n-Alkyl Acid Phosphate 2 only 3, 770 39 268 Amine Salt of di(2-ethylhexyl) hydrogen Phosphate:

3,4dichloroaniline; 3, 500 50 280 Di(2-ethylhexyl) hydrogen phosphate, only 2, 800 50 280 Amine Only: 3,4-dichloroani1ine 2, 200 32 1 2 wt. percent of the additive was blended into the base oil; tests were made on the resultant clear solution.

PHATES AS EXTREME PRESSURE ADDITIVES IN WHITE MINERAL OIL (NUJOL) Falex Seizure Test Maximum Bushing Seizure Torque at Temp, Load, lb. Seizure, F.

lb./in.

Additives 1 (Base Oil Only) 850 16 165 Amine Salt of Isooctyl Acid Phosphate: 2

o-Chloroaniline l, 600 39 m-Chloroaniline- 2, 125 40 232 p-Chloroanill 1, 975 34 275 2,4dichloroaniline. l, 850 31 262 3,4 dichloroaniliuc 2, 025 35 288 3-chloroo-toluidine 1, 700 35 200 fi-chloro-o-tolnidine. 1, 350 23 202 Isobctyl acid phosphate only l, 600 28 215 Amine Salt of 05-010 n-A'Lkyl Acid Phosphate: 2

o-Chloroaniliue 3, 725 40 272 3-chloro-o-toluidine 3, 875 48 315 3,4-dichloroanilinc 2, 525 36 220 Cs-Cia-n-Alk yl Acid Phosphate only 2, 575 34 247 Amine Salt of Di(2-ethylhexyl) hydrogen Phosphate:

3,4dichloroaniline l, 450 35 Di(2-ethylhexyl)-hydrogen phosphate only 1, 275 30 Amine Only: 3,4-dichloroaniline 2, 125 47 250 N orn.Sce footnotes after Table I.

Table II.Wizite mineral base 0il.-Blends of up to 2% of the chloroamine salts of isooctyl acid phosphate carry up to 153% greater load than does the mineral base oil alone and up to 34% greater load than the 2% blends of i ooctyl acid phosphate itself; similar benefits are observed for the chloroamine salts of C C n-alkyl acid Seizure Torque at Load, lb. Seizure, TAN 1 1b./in.

o-Chloroauiline Salt of isoctylghosphate: o-Chloroaniline Salt of isooctylphosphate:

3:1 mole ratio- 1. 7:1 mole ratio 1. 5:1 mole ratio 3, i-dichloroaniline Salt of isooctylphosphate:

1. 5:1 mole ratio Base Oil Only 1 Total acid number.

The negative concentration effect of the chloroamine salts of alkyl acid phosphates is illustrated by the following data from Falex Seizure Test.

Falex Seizure Test Seizure Load, Torque at lbs.

Seizure, lb./in.

3, 4-dichloroani1ine salt of -0 n- Alkyl Acid Phosphate:

-2% in Nujol 0.1% in Nujol -chloro-o-toluidine salt of mixed monoand diisooctyl acid phosphate:

-2% n Nujol 1 350 0.1% in Nujcl- 1, 775

B. F alex constant load wear test Following the same clean-up procedure described in A, above, the test bushings and test pin were weighed to the nearest 0.1 mg. They were then inserted into the text machine, a break-in load of 250 lb. applied and the ma chine operated with the test lubricant for two minutes. At the end of the break-in the load was increased automatically to 1500 lbs. where it was maintained constant for a period of 60 minutes.

At the end of the 60-minute run, the test pieces were removed and cleaned as they were in the initial step. After drying they were reweighed to determine the weight loss in mg. The weight loss of the two test bushings was reported as the sum of both bushings.

TABLE IV.FALEX CONSTANT LOAD WEAR TEST [1500 lb./60 min.] Base Oil: Di-oxo-tridecyl Adipate Weight Loss, mg.

Steel Bushings l 3,4-Dichloro Aniline Salt ZDATP 3 of Isooctyl ZDATP 3 Acid Phosphate A dditive Conc., Wt. Percent Steel Pin 2 3,4-Dichloro Aniline Salt of Isooctyl Acid Phosphate 1 SAE 4615-4620, 90 min. Rockwell B, ms. max.

1 Sanderson Special Drill Rod, 98-102 Rockwell B, 15 ms. max.

3 A zinc dialkyldithiophosphate, commercially available from the Lubrizol Corp., normally designated as #1060.

4 Cast Iron, 15 rms. max.

5 Excessive wear.

Table IV.Falex wear test.-The data for the 3,4-dichloroaniline salt of isooctyl acid phosphate are compared with those given by zinc dialkyldithiophosphate, the additive commonly used at the present time.

A typical chloroaniline salt has a negative concentration efiect in this wear test. The data in Table IV show that higher wear occurs at 2 wt. percent of the 3,4-dichloroaniline salt of isooctyl acid phosphate than occurs at 4 wt. percent in an esterlube base oil. This phenomenon should prove an advantage in break-in oils where rapid wear-in of the bearing mating surfaces is desired. As the additive is depleted the wear rate decreases to a normal level. This would obviate the need for a separate break-in lubricant followed by an oil change to a conventional lubricant.

C. Valve tappet scafling and wear Sequence IV (ASTM Special Technical Publication No. 315, American Society for Testing Materials, Philadelphia, Pa. (1962)) describes engine operating conditions likely to require special lubricant characteristics to reduce scufling and wear of valve tappets under high speed and high temperature operations.

Reference engine and pr0cedure.-Lubricant performance was determined by engine condition at the completion of a series of operations with a reference engine, run on the test stand with appropriate accessories for control of engine temperatures. The definitive operating conditions used with the reference engine are detailed below.

The engine required by the standard procedure is a 1962 Chrysler (361 cu. in. displacement), equipped with standard valve springs and fitted also with supplementary inner valve springs. The springs were adjusted to a 33% overload.

Reference sequence IVlzigh temperature, high speed tappet scufiing and wean-The reference engine was operated at 1200:50 rpm. for ten minutes, after which the oil drained, the oil filter changed, and new oil added. Without further warm-up, the engine was operated for two hours under the following conditions:

Following this two-hour period, the engine was shut down for two hours, with circulating tap water (35 to 75 F.) being used to cool the engine. This on-and-oif operation was repeated for five additional cycles, without initial warm up, after which the camshaft and tappets were removed for inspection.

Duplicate runs were made with the reference engine for better definition of the engine severity level.

Interpretation of engine conditio n.0n completion of the above sequence of operation, the camshaft and valve tappets were removed for inspection. The condition of the parts was based on visual inspection of the scufiing and wear. Ratings were assigned by use of a reference set of valve tappets.

Supplementary reference engine information-The reference engine was a normal production 1962 Chrysler V8 (361 cu. in displacement), equipped with standard valve springs (Part No. 1944854) standard production camshaft and pin assembly (Part No. 2268405) and standard tappets (Part No. 2084029). In addition, inner valve springs (Part No. 1555166) were installed. Using suitable spacers, the spring heights were set at 1.860 in. for the outer springs and 1.487 in. for the inner springs, to give a 260-1b. spring load at the valve-open position, which was 33 percent overload.

Some additional spacers were required (about in.) to obtain the desired height, 1.487 in., for the inner valve spring.

Engine coolant system.An external Water coolant system was employed to maintain the desired coolant Z temperature during engine operation, and to permit cooling the engine during the shutdown portion of each cycle.

Engine oil coolant system.-An external heat exchanger, of one-quart capacity, was used to maintain the desired oil temperature.

Duplicate rwzs.--On completion of the first run, the oil was drained, the oil filter removed, and the engine rinsed with flushing oil. A new oil filter, new camshaft, and a new set of tappets were installed. After addition of new oil, the engine was ready for the duplicate run, which followed the same definitive procedure as the first run, including initial warm-up procedure.

TABLE V.-VALVE TAPPET SOUFFING *1.5 to 1 mole ratio of aniline to acid phosphate.

Table V.Valve tappez seufiing-The data from this full-scale engine test confirm that obtained in the Falex wear test which showed a negative concentration effect for the 3,4-dich1oroaniline salt of isooctyl acid phosphate. At two weight percent in the esterlube base oil, all but one of the tappets failed-performance worse than that of the base esterlube. At /4 to /2 weight percent additive concentration, only one tappet failed giving performance almost equal to that of two weight percent of ZDATP, the standard type of antiscuifing additive used in most commercial motor oil.

Similar performance was observed in engine tests using this additive in a W30 mineral oil base stock.

D. GM single Zapper test (defined in Table VI) This test used a single-cam from a production automotive camshatt. A production valve tappet was springloaded against the cam. The tappet load was set at 163 pounds for a ten-minute break-in, and then the load was increased in 40 pound increments to a maximum load of 600 pounds.

Wear of the tappet surfaces was then determined by a sensitive gauge capable of measuring $3 of an inch.

TABLE VL-VALVE TAPPET WEAR TEST [GM Single Tappet Tester] 1 Base Oil White Mineral Oil of Lubricant Viscosity Grade Additive, wt. percent: Tappet wear, inches 2% 3,4-dichloroaniline salt of mixed isooctyl acid phosphate 0.0001 2% ZDATP 0.001 2% n-octyl pantachloro phenylthio acetate 0.0008 0.5% nickel dithiodicarbamate 0.0021

ports as a good antiwear agent.

8 Dynamic rust test for crankcase lubricants tour-ounce tall-form oil sample bottle in an oven at 140i5 F. for 24 hours. The synthetic exhaust condensate contained 0.02 weight percent of each of the follow-' ing chemicals in distilled water: Acetic acid,'hydrochloric acid, hydrobromic acid, lead chloride and lead bromide. The metal specimen is /8 inch thick 1020 steel, /2 inch wide, and six inches long. It was :boiled in benzene, sandblasted and then washed in naphtha and dried before placing in the bottl Fifteen bottles were placed in a special rack inside the oven. The rack was rotated at a speed of 30 rpm. The test called for alternating rotation for four hours and nonrotation time of 24 hours. At the end of the test period the iron speciment was rated for amount of rust according to the following table:

TABLE VII.ANTIRUST PROPERTIES [Sun-American oven rust test] 30 ml. Test Sample-l-S ml. Exhaust Condensate 140 F., 24 hours Rating White Ester Lube Additive, Weight Percent Mineral (Di-oxo-tri- Oil decyl Adipate) 2% 3-chloro-o-toluidiue Salt of Isooctyl Acid 9. 7 9. 7

Phosphate. 2% 5-chloro-o-toluidine Salt of Isooctyl Acid 9. 7 9. 5

Phosphate. 2% o-chloroaniline Salt of Isooctyl Acid 9.7 9. 5

Phosphate. 2% m-chloroaniline Salt of Isooctyl Acid 9. 7 9. 7

Phosphate. 2% p-chloroaniline Salt of Isooctyl Acid- 9. 7 9. 7

Phosphate. 2% 2,4-dichloroaniline Salt of Isooctyl Acid 9. 7 9. 5

Phosphate. 2% 3,4-dichloroaniline Salt of Isooctyl Acid 9. 7 9. 8

Phosphate. 1% 3A-dichloroaniline Salt of Isooctyl Acid 10 Phosphate. 3,4-dichl0roaniline Salt of Isooctyl Acid 1O Phosphate. 2% 3-chlor0-o-toluidine Salt of Cs-Cm-ll- 9.7 9. 7

Alkyl Acid Phosphate. 2% o-chloroaniline Salt of C5-C1Bn-Alkyl 9. 7 9. 5

Acid Phosphate. 2% 3A-dichloroaniline Salt of 0 -0 -n-Alkyl 10. 0

Acid Phosphate. 2% 3,4-dichloroaniline Salt of di-(2-ethyl 5. 5 5. 5

hexyl)hydrogen phosphate. 2% O -O -n-Alkyl Acid Phosphate 9. 7 7. 4 2% Isooctyl Acid Phosphate- 6. 5 8. 6 2% Di-(Zethylhexyl) hydrogen atet. 10. 0 10. 0 2% 3,4-dich1oroaniline 4 9. 2 Base Oil Only 5.4 5.2

1 These salts, except for are essentially neutral salts of the mixed allliyl acid, phosphate; the di (2-ethylhexyl)hydrogen phosphate is the dia y Table VII.--Antitrust pr0perties.The aromatic chloroamine salts of allcyl acid phosphates exhibit good anticorrosion properties in both mineral and ester base oils. Normally, chlorine is a pro-rust agent and most halogenated extreme pressure or 'antiwear additives are used where the presence of rust is not serious or can be avoided through other means.

The aromatic chloroamine derivatives are better antirust agents than the isooctyl acid phosphate in both the mineral base and the ester base oils. They were also superior to the n-alkyl phosphate in the ester base oil and equal in the mineral base oil. As the data in Table VII indicate, all of the additives were superior to the base oils, themselves. The preceding representative examples may be varied within the scope of the present total specificafor four hours for a total 9 tion disclosure, as understood and practiced by one skilled in the art, to achieve essentially the same results.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are as follows:

1. A lubricant composition having improved antiwear and load carrying ability, said composition comprising essentially a lubricating oil and 0.05 to 2.0% by Weight of the oil of a salt of a chloroaniline selected from the group consisting of orthochloroaniline and 3,4-dichloroaniline and mixed monoand di-isooctyl acid phosphate.

2. A lubricant composition according to claim 1, said References Cited UNITED STATES PATENTS 3,116,248 12/1963 Frew 252-325 3,116,249 12/1963 Ratner et al 25232.5 3,203,895 8/1965 Latos et al 252-32.5 3,247,109 4/1966 Benoit 25232.5 X

DANIEL E. WYMAN, Primary Examiner. P. P. GARVIN, Assistant Examiner.