US2358581A - Lubricant - Google Patents

Description

Patented Sept. 19, 1944 LUBRIGAN T Eugene Lieber, West New Brighton, Staten Island, N. E, and Aloysius F. Cashman, Bayonne, N. 3., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 24, 1941,

Serial No. 424,289

12Claims.

This invention relates to improved lubricants, and more particularly to the addition of a corrosion preventer to lubricating oils which are normally corrosive to metals coming in contact therewith.

In the manufacture of lubricating oils, it is often desirable to incorporate small amounts or even substantially large amounts of materials which have some special beneficial effect, such as increasing the oiliness. or load-carrying capacity of the lubricating oil base stocks, even though such materials may impart thereto a tendency to corrode metals coming in contact with the lubricants. Thus, for imparting high film strength to oils to be used for lubricating bearings in engines, gears and other moving metal parts which contact each other under high pressures, as well as for cutting oils as used for machining various metals, these lubricants are often compounded by adding to a mineral lubricating oil base stock substantial amounts of chlorinated materials, either alone or in combination with sulfur compounds and sometimes phosphorous'compounds. Such lubricants tend to rust the gear surfaces which are being lubricated and also cause. corrosion and staining ferrous, copper-bearing alloys used in bearings, bushings, pistons, etc. Also, sulfur alone or in the presence of chlorine, especially cutting fluids, usually causes a black stain such as copper sulfide, on copper alloys. Other industrial oils such as turbine oils generally cause or permit a certain amount of corrosion of the metal parts.

It has now been found that these corrosive tendencies of the lubricant can be substantially reduced, without substantially interfering with the other more desirable characteristics of the lubricant. The invention is particularly applicable to lubricants containing active halogen and/or sulfur, and especially to such lubricants containing more than 1/z% of chlorine, based on the total weight of lubricants,

' Broadly, the invention comprises adding to a lubricant which is normally corrosive to metals, a small amount of an oil-soluble amide. Although amides containing an unsubstituted amino group are considered to come within the scope of the invention, it is preferred to use amides in which one 'or both of the hydrogen atoms attached to thenitrogen in the amino group, are substituted, i. e. replaced, by an organic group which may be a simple hydrocarbon group such as an alkyl group or may be a com plex group such as that derivedfrom a polyolefln polyamine. The amide may therefore broadly be considered as a compound containing at least one group Ac-N, in which Ac represents an acyl group or an acid radical, such as fatty acids, naphthenic acids, or various dibasic or other polybasic acids. The amides or N-substL tuted amides to be used should ordinarily contain more than carbon atoms and preferably more than carbon atoms.

The simpler amides coming within the scope of the invention may be considered to have the general .formula Ac-NRR' in which Ac represents the acid radical and R and R represent either hydrogen or an organic group. Preferably, at least one of either R and R is either an alkyl group or contains a substantial amount of aliphatic carbon atoms. Examples of some of these amides are the following: N-octyl stearamide having the formula CnHasCONHCaHn, N,N,diamyl stearamide, N diamyl oleyl amide, N,N',diamyl sebacamide, N-octyl amide of petroleum naphthenic acids, N diamyl amide of petroleum naphthenic acids. I

An example of a more complex amide suitabe for the present invention and, in fact a preferred type of amide is the naphthenamide of trieth- By the term naphthenamide is meant the all naphthenic acid amide. Since the poly-olefin poly-amines such as the triethylene tetramine and tetraethylene pentamine, having an amino group at each end of the molecule, each of these terminal amino groups would normally tend to react when added to acarboxylic acid chloride, and therefore the resultant acid amide would have two acid radicals linked together by a poly. olefin polyamine group.

The amides of this invention, having the amino nitrogen atom linked directly to the carbonyl carbon atom of the acid, are not to be confused with plain amines or amine salts or soaps, in which latter cases the nitrogen atom is linked to an oxygen atom and not to a carbon atom in the acid radical.

base stocks can be used such as distillate or residual fractions derived from paraifinic, naphthenic, or other typed 'crudes, and these various fractions may have been subjected to any of the known refining or treating processes such as acid treating, clay treating, solvent extraction, etc.

Generally, the amount of the amide to be used will depend to-a substantial extent upon theamount of constituents present which have corrosive tendencies, but normally the amount of amide should be about 0.1%-5.0%, and generally, or preferably, about 0.3%2.0%. For instance, 0.5% has been found very suitable fo most purposes.

The invention is particularly applicable to extreme pressure lubricants containing corrosive chlorine compounds, for instance, chlorinated derivatlves of aliphatic or aromatic hydrocarbons .types of lubricant such as of the water-soluble type, e. g. cutting oil), 7

In preparing extreme pressure lubricants of the active halogen type, it is frequently desirable to incorporate sulfur compounds, especially to increase the stability of the lubricant at high temperature, and for this purpose a sulfurized-fatty or mineral oil, or a sulfur compound such as an organic sulfide, mercaptan, di-. or poly-sulfide, xanthate, xanthogen sulfides, thiocarbonates, etc., may be used, in which generally from about 1% to 30% of sulfur is incorporated in the active .or combined state. Based on the total weight of lubricants, the proportion of sulfur should normally be between the limited about 0.2% and 10%. Instead of using separate chlorine compounds and sulfur compounds, it is possible to use single materials in which both. sulfur and halogen have been incorporated by treatment with a sulfur halide or by reacting the halogen compound with an inorganic sulfide, polysulfide, thiocarbonate, or xanthate.

One example of an extreme pressure lubricant is one composed of 83% of mineral oil, 10% of sulfurized non-corrosive fatty oil base such as sulfurized sperm oil containing 10% sulfur, and 7% of chlorinated paraffin wax containing about 40% of chlorine. Another extreme pressure lubricant ma be made by reacting sodium polysulfide with a chlorinated hydrocarbon such. as chlorinated kerosene, and blending the resultant products with mineral oil. A cutting oil maybe prepared by incorporating a small amount, such as 0.8%, of elementary sulfur into a mineral oil such as one havinga viscosity of about 100 sec-' onds Saybolt at 100 I".

The amides of the presentinvention areintended to be incorporated in any of these lubricants which are normally corrosive to metals by reason of the presence of active chlorine and/or sulfur. y I

In preparing lubricants according to this invention, it is also possible and in certain cases fatty acids, soaps of fatty acids or naphthenic acids, esters, thickeners of various types such as polyisobutylene having a molecular weight above 1,000, V. I. improvers, pour depressors such as the'ones made by F'riedel-Crafts condensation of chlorinated paramnwax with naphthalene, antioxidants, oil-soluble metal soaps, dyes, etc.

The following description gives the details of preparation of one kind of extreme pressure agent, namely, a sulfurized chlorinated kerosene:

Water white kerosene was chlorinated in a glass vessel (nickel could be used) to 41.5% 01., temperature of reaction being regulated in such a manner, as to keep it below the flash point at all times. Thus in the early stages of chlorination, the temperature was held at F., whereas the flash of the feed kerosene was 123 F. When the percentage of chlorine added reached approximately 20% by weight, the reaction tem perature was allowed to' rise to F. and was maintained at this point until the desired amount of chlorine (41.5% by weight) had been added.

The following reactants were then used to prepare an extreme pressure agent:

Chlorinated kerosene (41.5% Cl) gms 800 91% isopropyl alcohol cc 850- Aqueous NaSH (32% NaSH) gms 212 Aqueous caustic (25% NaOH) gms 98 Elementary sulfur gms 20 'I'he-.'above materials were placed in a glass (nickel could be used) reactor equipped with reflux condenser, gas outlet, thermometer and electrical stirrer. Agitation was started and the temperature of the mix was gradually raised to reflux (178 F.). Small samples were withdrawn at regular intervals and allowed to settle, then were returned to the reactor. After refluxing for 1 /4 hrs. the sample withdrawn separated immediately into three distinct layers, as follows:

Top layeralcohol+small amount E. P. agent yellow color.

Middle layer-E. P. agent+small amount alcohol--black.

Bottom 1ayer-brine+solid NaCl-water white.

This type of separation-has come to be regarded as indicative of the end point of the reaction, for tests have shown that the brine is acidic and consequently contains no sodium sulfide.

The reaction was continued at reflux for an additional 30 minutes and then cooled and settled. The brine was withdrawn and discarded; the top layer of alcohol was retained for recycling purposes.

The middle layer of crudeextreme pressure agent was stripped of residual alcohol under high vacuum over an oil bath at 230 F. and filtered under suction to remove any solid materials. e. g. NaCl. The yield-was 731 gms. of extreme pressure agent whichranalyzed at 7.0% sulfur and 32.6% chlorine.

The following data will illustrate several modifications of the invention and will make the advantages of the invention clearly apparent.

An extreme pressure lubricant was prepared by blending with 90% of a mineral oil base stock having a viscosity of about 200 seconds Saybolt at 210 F. and derived from a Panhandle crude, 10 of a sulfurized chlorinated kerosene. made by the method just described above but contain- 'ing 7.2% of sulfur and 33.1% of chlorine. This may be desirable to incorporate other known addition agents such as, for instance, fatty lubricant was considered as thecontrolblend.

Four other blends were made just like-the con- -tx'ol except that 0.5% of the extreme pressure Chrysler Almen corrosion test with the ethylene pentamine.

lubricating agents, namely, the sulfurized chlorinated kerosene, was replaced by 0.5% of a corrosion-preventing amide of this invention. These five blends were then subjected to a loadcarrying test on the S. A. E. machine and to the results indicated in the following table:

The above table shows that the various amides tested either substantially or completely eliminated the corrosive tendencies of the extreme pressure lubricants, yet without materially affecting the load-carrying capacity.

The naphthenamide of tetraethylene pentamine used in test 4 was made as follows:

Naphthenic acids (approx. M. W.=266) were treated with slight excess of phosphorus trichloride at 200 F. for 2 hours with occasional vigorous shaking. The mixture was allowed .to settle and the phosphorus hydroxide went to the bottom of the flask.

95 gins. of the naphthenyl chloride was decanted into 200 -ccs. of benzene, 90 gms. of tetraethylene pentamine was slowly added to the solution with vigorous shaking. Considerable heat was evolved. The mix was then slowly raised to reflux and held there for 1 hour with occasional vigorous shaking. After cooling water was added and the mass was extracted with ethyl ether to remove the amide, the amine hydrochloride being left behind in the water. The ether solution was washed with water to remove last traces of the amine hydrochloride, dried over anhydrous sodium sulfate and stripped of solvent under high vacuum to a bottoms tem-.

perature of 400 F. The yield consisted of 95 gms. of a pale red resin with a, green cast. This product is the naphthenamide of tetraethylene pentamine.

The naphthenamide of triethylene tetramine used in test 3 was prepared by using exactly the same procedure and quantities of materials as above, except that'70 gms. of triethylne tetramine were used instead of 90.gms. of tetra- The yield consisted gms. of pale red resin .with a green cast.

Similarly, this method may be used to prepare other substituted naphthenamides generally.

It is not intended that this'invention be limited to any of the particular examples which have been given merely for the sake of illustration, nor unnecessarily by any theory as to the mechanism of 'the operation of the invention, but only by the appended claims in which it is intended to claim all novelty inherent in the invention as well as other modifications coming within the scope and spirit of the invention.

We claim:

1. An extreme pressure lubricant comprising a mineral oil having dissolved therein an organic material containing metal-con'oding constituents selected from the group consisting of halogen and sulfur, and an oil-soluble N-alkyl substituted caracid radical contains at least 7 carbon atoms.

4. An extreme pressure lubricant according to claim 1 containing an oil soluble naphthenamide of a poly-olefin poly-amine.

5. An extreme pressure lubricant according to claim 1 containing an oil soluble naphthenamide of tetraethylene pentamine.

6. An extreme pressure lubricant according to claim 1 containing anoil soluble N-alkyl substituted amide of petroleum naphthenic acid.

7. An extreme pressure lubricant'according to claim 1 containing an oil soluble N-alkyl substituted amide of a fatty acid containing at least 10 carbon atoms.

8. An extreme pressure lubricant according to claim 1 in which the carboxylic acid amide contains more than 10 carbon atoms.

9. An extreme pressure lubricant comprising a mineral oil having dissolved therein an organic material containing at least 1.5% of halogen and a corrosion-preventing amount of an oil-soluble N-alkyl substituted carboxylic acid amide in which the carboxylic acid contains at least 7 carbon-atoms.

10. An extreme pressure lubricant according to claim 9 containing chlorinated kerosene and about 0.3 to 2.0% of an oil-soluble naphthenamide of tetraethylene pentamine.

11. An extreme pressure lubricant according to claim 9 containing in addition at least 0.2% of sulfur.

12. An extreme pressure lubricant comprising a mineral oil having dissolved therein an organic material containing at least 0.8% of sulfur and about 0.3 to 2.0% of an oil-soluble N-alkyl substituted carboxylic acid de in which the carboxylic acid radical contains at least 7 carbon atoms. I