US2753307A - Lubricants containing oxidized hydrocarbon oils - Google Patents

Description

LUBRICANTS CUNTG OXIDIZED HYDRUCARBUN @HLS Applicah'on September 11,1952, enial No. 309,142

6 Claims. (Cl. 252-55) No Drawing.

This invention pertains to new compositions of matter comprising lubricating oils and certain oxidized hydrocarbon oils. The new compositions of matter herein are particularly useful in steam cylinder oil compositions and in traction gear lubricants.

This application is a continuation-in-part of Foehrl-lanly application Serial No. 224,846, filed May 5, 1951, and now abandoned.

As steam cylinder oils, the compositions of this invention are more eilicient than steam cylinder oils heretofore available. When steam alone is used in the operation of steam cylinder engines, the steam per se does not afford suffieient lubrication along the cylinder walls and related parts to permit continued operation of the engine without the consequences due to friction, that is, high rate of wear, heat, etc. it is essential that some means of lubrication be provided along the cylinder walls of steam-operated engines.

initially, mineral oils were injected into steam cylin ders to assist in the lubrication. More recently, it has been the general practice to inject certain mineral oil compositions containing fatty substances. For example, it has been the practice to incorporate such fatty substances as lard oil, tallow, or degras in a mineral oil as emulsifiers to assist in dispersing the oil droplets over the metal surfaces in the presence of water. Even with emulsifiers, the most highly efifective steam cylinder lubricating oil compositions have been available only by the use of Pennsylvania bright stocks as the base oils. The use of other bright stocks and other residual stocks has been quite unsatisfactory in that proper lubrication has not been available therefrom.

As traction gear lubricants, the compositions of this invention avoid difiiculties experienced with presently used traction gear lubricants. Traction gear assemblies (e. g., Diesel locomotive engine traction gears) are normally housed in such a manner that it becomes essential for good lubrication to use viscous lubricants; lubricants which will adhere to the gears and not leak from the gear housing.

Traction gear lubricants now are being used contain thickening agents which are readily oxidizable, leaving black, brittle deposits on the gears and the surrounding gear box. in addition, these lubricants have such poor viscosity temperature relationship that, in order to provide a lubricant which is viscous at operating temperatures, the lubricant must be essentially a solid at room temperature or below. Thus, the starting of Diesel locomotives in the cold becomes diflicult.

Traction gear lubricants prepared from the new compositions of this invention are soft and pliable in the cold, and they are viscous at operating temperatures; giving excellent lubrication without excessive leakage.

it has been discovered that new compositions of matter useful as steam cylinder lubricants and traction gear lubricants may be prepared by treating certain petroleum hydrocarbon oils with an oxygen-containing material,

(e. g., oxygen) and incorporating the resulting oxidized petroleum hydrocarbon oil in an oil of lubricating viscosity. The new compositions of matter of this invention comprise oils of lubricating viscosity and oxidized petroleum hydrocarbon oils.

The petroleum hydrocarbon oils which are selected for treatment with oxygen are the petroleum hydrocarbons residual stocks having molecular weights ranging from 400 to 1000. It is preferred to use petroleum hydrocarbon residual stocks having molecular weights ranging from 600 to 800, because a more proper balance is obtained between the hydrophilic and hydrophobic properties of the oxidized petroleum hydrocarbons.

It is preferred to use petroleum hydrocarbon residue. which do not initially contain asphaltenes. Residual stocks which do contain asphaltenes should preferably have the asphaltenes removed before oxidation. Residua which are especially desirable for use as a source of hydrocarbon material for oxidation are the petroleum residua known as bright stocks.

The oxidized hydrocarbon residual stocks of the proper resin content (as hercinbelow described) are normally diluted with unoxidized lubricating oils which include a wide variety of lubricating oils such as naphthenic base, paratlln base, and mixed base mineral oils, other hydrocarbon lubricants, e. g., lubricating oils derived from coal products and synthetic oils, e. g., alkylene poly mers (such as polymers of propylene, butylene, etc., and mixtures thereof), alkylene oxide type polymers, dicarboxylic acid esters and liquid esters of acids of phosphorus. Synthetic oils of the alkylene oxide type polymer which may be used include those exemplified by alkylene oxide polymers (e. g., propylene oxide polymers), and derivatives, including alkylene oxide polymers prepared by polymerizing alkylene oxides (e. g., propylene oxide) in the presence of water or alcohols, e. g., ethyl alcohol, and esters of alkylene oxide type polymers, e. g., acetylated propylene oxide polymers prepared by acetylating the propylene oxide polymers containing hydroxyl groups.

During the oxidation of petroleum hydrocarbon residua, resins originally present become oxidized; also, the resin content is increased. Prolonged oxidation of petroleum hydrocarbon residua should be avoided. Too vigorous oxidation results in the formation of asphaltenes. Thus, it is preferred to oxidize the petroleum hydrocarbons up to the point where asphaltenes are formed, so that the final product is essentially free of asphaltenes.

As herein used, the term resins means the portion adsorbed on fullers earth and elutable with benzene alcohol solvent as described in the following process which was used in determining the amount of resins present in a particular petroleum residual stock.

A IOU-gram sample of residuum was warned with 2 liters of petroleum ether and allowed to stand for 16 hours at F. to separate out the asphaltenes. The undissolved asphaltenes were removed by filtration. The filtrate was distilled until the petroleum ether content had been reduced to a concentration ranging from 25 to 50%, afterwhich the filtrate was poured on top of a 30 to 60 mesh fullers earth in a Soxhlet extraction apparatus containing 550 grams of fullers earth. After standing over night, petroleum ether was recycled in the Soxhlet for 8 hours to remove the oil and wax fractions from the fullers earth. The resinous material adsorbed by the fullers earth was then removed by cycling a 50 to 50 solution of benzene-ethyl alcohol in the Soxhlets for 8 hours. The resin solution was then heated on a steam plate to remove the benzene-alcohol solvent.

The residual stocks which are oxidized to form the lysts used in the air-blowing of asphalts.

As noted hereinabove, it is desirable to use oxidized petroleum stocks which do not contain asphaltenes, and that the oxidation of the hydrocarbon stocks should continue until asphaltene formation begins. However, another factor is the final viscosity of the oxidized residual stock. The final viscosity of the oxidized hydrocarbon may range from 100 SSF to 4000 SSF at 210 F. For example, when used in steam cylinder oils the final viscosity of the oxidized residual stocks may range from 500 SSF to 4000 SSF; 1500 SSF to 2000 SSF at 210 F. being preferred. When used for traction gear lubricants the final viscosity of the oxidized hydrocarbon may range from 100 to 600 SSF at 210 F.

By measuring the viscosity of the petroleum stocks during oxidation, it is possible to determine the stage at which the oxidation should be discontinued, at which stage the resin content is at its maximum and ahphaltenes begin to form. This is illustrated by the following curve, plotting viscosity versus resin content:

Asphaltcnes Begin to form Resin Content The amount of resins from oxidized hydrocarbon oils as determined by the procedure outlined hereinabove which are useful for the purposes of this invention, range from 2% to by weight based on the finished composition. It is preferred to use from 7% to 20% of resins in the finished composition, said resins being obtained from oxidized hydrocarbon oils.

Though less preferable, it is within the broader scope of this invention to oxidize the desired hydrocarbon radical stock just sufi'iciently to give the proper amount of resins in the oxidized product so that this product per so may be used as a steam cylinder lubricant or traction gear lubricants.

Although lubricating oil compositions containing the oxidized hydrocarbon oils of this invention are satisfactorily used as steam cylinder oils per se, emulsifiers are usually added to assist the dispersion of the oil in water. Emulsifiers which can be used include fats, oxidized fats, polyoxyethylene esters of mixed fatty and resin acids (e. g., polyoxyethylene, sorbitol-oleate-laurate), polyoxyethylene lauryl alcohol, trihydroxy ethyl amine stearate, glycol borate, glyceryl borate, sorbitan monolaurate, polyoxyethylene stearate, etc. The emulsifiers can be used in amounts of 0.1% to 15% by weight, based on the final composition; normally, from 0.1% to 7% for adequate for the purposes of this invention.

Similarly, in addition to the oxidized hydrocarbon oils, traction gear lubricants may contain grease thickening agents. For example, the traction gear lubricants can contain metal soaps (e. g., sodium stearate), and other grease-thickening agents (e. g., polyethylene). These grease-thickening agents can be used in amounts of 1% to 10%, 2% to 4% being preferred.

The agents of this invention are certain resin-containing products of oxidation of residual S'tQG as defined hereinabove, and, because of their unique character, they impart to such oils as derived from Mid-Continent, Gulf Coast and California crudes, properties which make the resulting composition superior with respect to lubrication, viscosity index, pour point, etc., as compared to the same oils compounded with other agents. The effect of the agents of this invention in improving lubricating properties (e. g., steam cylinder oils) is particularly noticeable when oxidized stocks of this invention are incorporated in oils of lubricating character derived from solventrefined California crudes.

With special regard to the composition herein as steam cylinder lubricants, the most highly effective steam cylinder lubricants were formerly available by the use of Pennsylvania bright stocks, that is, Pennsylvania steamrefined long residua. Even these Pennsylvania steam cylinder lubricating oils are improved by incorporating therein the oxidized residua of this invention.

In order to evaluate the compositions of this invention as steam cylinder lubricants, a means of testing the composition was devised. The test equipment is a modification of the Martin Valve Controller used in saw mills. The Martin Valve Controller is essentially a double-acting, valve-in-piston steam engine employed in steam-powered saw mills as a booster to aid the sawyer in opening and closing the main steam stop valves which control the steam flow to the log carriage engine. Proper lubrication of this controller is essential to the smooth forward and reverse operation of the carriage. If the lubrication is inadequate for the smooth functioning of the Martin Valve Controller, the carriage does not stop and reverse itself properly; thus, the carriage moves on with a force which in some instances is sufficient to drive the carriage through the end of the building.

In the modified Martin Valve Controller test used to evaluate the compositions of this invention, a pump was operated through the Martin Valve Controller. The data obtained show the pressure (in pounds per square inch) which was available from the pump. The greater the pressure exerted by the pump, the less the friction in the Martin Valve Controller, and the better the lubricant used in the Martin Valve Controller.

Table I below presents data obtained in the Martin Valve Controller Test with oils containing oxidized bright stocks. Because Pennsylvania base bright stocks per se were heretofore the preferred steam cylinder lubricants, these bright stocks were used as a standard for the test data hereinbelow. All of the compositions used in obtaining these data contained 7% fatty substances; namely, acidless tallow oil.

The oxidized bright stocks were obtained as follows: California solvent-refined bright stocks having viscosities of about SSU at 210 F. were oxidized by bubbling oxygen into the bright stocks at 425 F. for periods ranging from 7 to 30 hours, using ferric chloride as the catalyst. The resulting oxidized materials contained from 35% to 55% resins, and no asphaltenes.

Table l Amt. of Resins in final composition (percent at 30 by Wt.) p. s. i.

Viscosity Martin Valve of oxi- Controller Test dized material at 210 F. (SSU) Amt. of oxidized material Base Oil 1. Penna 2. Calif. Parafiinic. 381 3. Calif. Paraifinic. 4 5

. Calif. Paraifinic.- Calif. Paraflinicn 1 A resin extracted from an oxidized California, Louisiana and Mississippi residua.

The effectiveness of compositions of this invention as traction gear lubricants was measured by numerous tests;

e. g., leak ge tests, viscosities, etc.

To determine the amount of leakage, a scale model (approximately one-third of actual size) of a traction gear assembly was built. This scale model was operated for 6 hours at speeds and temperatures simulating actual starting, running, and stopping of Diesel locomotives: after which the percentage of grease which had leaked from the assembly was noted.

The data of Table II hereinbelow show that the compositions of this invention are superior to presently used gear lubricants, in that the lubricants of this invention are soft at room temperatures, and are sufiiciently viscous at operating temperatures to avoid excessive loss through leakage.

Oil A of Table II was a California solvent-refined paraflin base oil having a viscosity of 185 SSU at 210 F.

Additive A was an asphalt currently available from the Berry Asphalt Company of Magnolia, Arkansas. This asphalt was added to improve further the metal wettability of the lubricants.

Additive B Was an oxidized bright stock. Oxidized bright stocks were obtained by blowing air into California solvent-refined bright stocks having viscosities of about 185 SSU at 210 F. for periods from 7 to 20 hours at 425 F. The resulting oxidized bright stocks contained from 35% to 55% resins, and no asphaltenes.

Product A was a commercially available currently used traction gear lubricant.

Table II 36 Leakage, percent Loss The new compositions of the present invention are useful in greases and lubricating compositions in general, Wherever a stable thickening property is desirable along with characteristics of excellent adherence to metals. These compositions are also useful as coloring agents for lubricating compositions.

We claim:

1. A lubricating composition comprising essentially a hydrocarbon oil of lubricating viscosity and an amount of oxidized bright stock containing high molecular weight, resinous oxidation products, sufficient to obtain a concentration in the hydocarbon oil of from 2 to 25% by Weight of the said resinous products, the resin content being determinable by adsorption of the resins on fullers earth and elution therefrom with benzene-alcohol solvent; said bright stock being substantially free from asphaltenes in the unoxidized state and being oxidized by being contacted with an oxygen-containing gas at a temperature of from 300 to 500 F. for a period of from 7 to 30 hours to produce a product having a viscosity of from to 4000 SSF at 210 P. which contains said high molecular weight resinous oxidation products and is substantially free from asphaltenes.

2. A lubricating composition according to claim 1 in which the unoxidized bright stock has a viscosity of about SSU at 210 F.

3. A lubricating composition according to claim 1 in which the unoxidized bright stock has a molecular weight of from 400 to 1,000.

4. A lubricating composition comprising essentially a hydrocarbon oil of lubricating viscosity and from 2 to 25% by weight of high molecular weight, resinous oxidation products derived by oxidation of a bright stock, said resin content being determinable by adsorption of the resins on fullers earth and elution therefrom with benzene-alcohol solvent; said bright stock being substantially free from asphaltenes in the unoxidized state and being oxidized by being contacted with an oxygen-containing gas at a temperature of from 300 to 500 F. for a period of from 7 to 30 hours to produce a product having a viscosity of from 100-4000 SSF at 210 F. which contains said high molecular weight resinous oxidation products and is substantially free from asphaltenes.

5. A lubricating composition according to claim 4 in which the unoxidized bright stock has a viscosity of about 185 SSU at 210 F.

6. A lubricating composition according to claim 4 in which the unoxidized bright stock has a molecular weight of from 400 to 1,000.

References Cited in the file of this patent UNITED STATES PATENTS 1,831,614 White NOV. 10, 1931 1,904,065 Mackenzie Apr. 18, 1933 1,924,211 MacLaren Aug. 29, 1933 2,128,574 Van Peski Aug. 30, 1938 2,339,898 White Jan. 25, 1944 2,508,016 Doyle May 16, 1950

Claims (1)

1. A LUBRICATING COMPOSITION COMPRISING ESSENTIALLY A HYDROCARBON OIL OF LUBRICATING VISCOSITY AND AN AMOUNT OF OXIDIZED BRIGHT STOCK CONTAINING HIGH MOLECULAR WEIGHT, RESINOUS OXIDATION PRODUCTS, SUFFICIENT TO OBTAIN A CONCENTRATION IN THE HYDROCARBON OIL OF FROM 2 TO 25% BY WEIGHT OF THE SAID RESINOUS PRODUCTS, THE RESIN CONTENT BEING DETERMINABLE BY ADSORPTION OF THE RESINS ON FULLER''S EARTH AND ELUTION THEREFROM WITH BENZENE-ALCOHOL SOLVENT; SAID BRIGHT STOCK BEING SUBSTANTIALLY FREE FROM ASPHALTENES IN THE UNOXIDIZED STATE AND BEING OXIDIZED BY BEING CONTACTED WITH AN OXYGEN-CONTAINING GAS AT A TEMPERATURE OF FROM 300 TO 500* F. FOR A PERIOD OF FROM 7 TO 30 HOURS TO PRODUCE A PRODUCT HAVING A VISCOSITY OF FROM 100 TO 4000 SSF AT 210* F. WHICH CONTAINS SAID HIGH MOLECULAR WEIGHT RESINOUS OXIDATION PRODUCTS AND IS SUBSTANTIALLY FREE FROM ASPHALTENES.