US2251774A - Lubricant additive - Google Patents

Description

Patented Aug. 5,1941

UNITED STATES PATl-ZINT OFFICE cago, and Hans Schindler, signers to The Pure Oil Company, Chicago,

a corporation of Ohio No Drawing. Application December 28,1939, Serial No. 311,244

26 Claims This invention relates to lubricatingoils and to processes for improving their properties and more particularly to the production of lubricatingoils having reduced pour tests.

Lubricating oil stock's, particularly those derived from parafllnic and mixed base crudes, contain appreciable amounts of wax and, therefore, have a relatively high pour test unless a substantial amount of this wax is removed. The wax may be removed by various methods such as cold settling, filtration or centrifuging. However, 'such processes are expensive and even after such processes have been practiced, lubricating stocks may still retain appreciable amounts of wax and may have pour tests above 15 F. and even up to about 50 F. The removal of additional quantities of vwax from these stocks necessitates further expensive processing. Furthermore, complete removal of wax from an oil frequently causes the removal of other materials valuable as lubricants, as well as causing an undesirable increase in the rate of change of the viscosity of the oil with temperature, that I is, such removal of wax results in a lower vis-= cosity index of the oil. It is therefore of advantage to add to the oil a material which will reduce the pour test without it being necessary to remove all or substantially, all of the wax. Materials such as wax, which are generally presumed to cause high pour point tests in lubricating oil, apparently act by partly crystallizing from the remainder of the oil in such a way that a lattice or honeycomb interlacing or interlocking structure is formed which prevents the free flow of the oil.

One method of lowering the pour point. of oil depends not on removing the materials responsible for such lattice structure, but on adding to the oil containing all or only part of them, such a material as will completely or partially waxed or whether containing all of its natural" wax content. For example, a substantial lowera ing of the cold test of the oil may be obtained relatively economically by pressing the wax bear ing oil at a relatively high temperature, such as for example, approximately 60 F. whereby a portion of the wax is removed and then adding material prepared in accordance with this invention to reduce the pour test of the pressed oil.

inhibit or interfere with the formation of such a structure and thus permit the oil to flow freely at lower temperatures than it would without the added material.

Although it is believed that the foregoing discussion is a reasonably accurate explanation of the function of pour depressants, it is not desired that this invention be limited by this theory The refrigeration required to obtain this temperature in commercial practice is not particularly great. A large lowering of the cold test of the oil may be obtained in this way at little expense in contrast to the considerably increased cost of lowering the cold test by operating-the pressing process at a sufliciently low temperature to obtain the same pour test, It is obvious that greater quantities of the addition agents will be required to lower the pour point of a wholly undewaxed oil than for one which has been partially dewaxed. Thus in the preferred embodiment of the invention it is preferred to partially dewax the oil by pressing at relatively high temperature or centrifuging or some other conventional method, since the cost of the high temperature dewaxing operation plus relatively large quantities of pour depressant is usuallymuch less than the cost of low temperature dewaxing operations plus relatively small quantities of pour depressant. Rather than process at low temperature, it is preferred to add one or more of the addition agentsherein described so as to obtain the same lowering of the pour point by this less expensive method and without loss of yield of lubricating constituents.

An object of the present invention is to provide lubricating oils of low pour test.

Another object is to provide new pour point depressing materials to be added to lubricating oils.

Other objects and advantages will appear from the detailed description which follows.

densation of petroleum resin with halogenated, preferably chlorinated hydrocarbons, particularly those hydrocarbons of the-paraflin series? Condensation may be effected by any of the w'ell known condensing agents such as metallic lialides, especially aluminumchloride. A convenient: and economical'source of such paraflln'hydro-w carbons may be petroleum wax such as the usual; paraflin wax or petrolatumwhich ,is'obtained in the course of conventional-refining methods applied to the manufacture oflubricatingoils.

2 I Resins suitable for the condensation reaction are those resins obtained from spent or partially spent adsorbents which have been used in decolorizing operations on petroleum oils such as neutral oils, bright stocks and cylinder stocks. Such resins may be conveniently obtained by extracting the spent adsorbents with chloroform or a mixture of benzol and alcohol or a similar solvent. In order to reduce the amount of oil in the resins, the spent adsorbent is preferably washed with petroleum naphtha prior to the extraction with benzol and alcohol or chloroform. The resin may be readily separated from the solvent-resin solution by distillation and is obtained as a dark brown viscous fluid. If the petroleum 'oil which is decolorized by contact with the adsorbent contains excessive 'asph'altic material, it may be desirable to separate at least I a portion of this asphaltic material prior to contact'with the decolorizing adsorbent. This may be readily accomplished by any. of several well-' known de-asphaltizing methods, for example, by the use of propane.

Pour point depressors in accordance with this invention have been prepared by chlorinating petrolatum of, for example, about 140 F. melting point, with chlorine gas until the petrolatum contained approximately to chlorine by 'weight. The temperature was controlled during the chlorination operation so that the temperature was not substantially in excess of 300 F.

The chlorinated product was mixed with hydro-' carbon resin obtained from partiallyspent decolorizing clay which had been used to decolorize Pennsylvania cylinder stock. This resin was obtained by first washing the spent clay with naphtha to remove any oil that may have been present and then extracting the naphtha-washed clay with chloroform. The chloroform was distilled from the resin-chloroform solution and the resin obtained as a dark brown, sticky fluid of approximately 1.02 specific gravity and about 590 seconds. Saybolt Universal viscosity at 210 F.

approximately three parts of hydrocarbon resin to two parts of chlorinated petrolatum.

The effect of the addition of anadditive in accordance with this invention and prepared as set forth in the preceding paragraph, on the pour point ofa high-grade lubricating oil consisting of a blend of bright stock andv neutral oil may be readily seen by reference to Table I:

Table I I A. S. T. M. pour test, 9F. Mineral oil; S. A. E. 20 +25 Mineral oil+1% additive 5 The additive shown in Table I was prepared by condensing three parts of resin with two parts of petrolatum which contained approximately 10% chlorine.

From the above table the efiiciency of additive prepared in accordance with'this invention is fully demonstrated. While in the foregoing tests 1 of the additive was blended with the lubricant, this amount may be varied within rather wide limits depending upon such factors as the quality and pour test of the original lubricant and composition of the additive.

Although the foregoing description sets forth a preferred embodiment of the invention and a preferred mode of carrying the same into effect, it will be readily apparent to those skilled in the art that many variations and modifications may The chemical condensation of the. chlorinated I petrolatum and resin was effected by adding anhydrous aluminum chloride to the mixture as a condensation catalyst and gradually heating to a temperature of approximately 200 F. to 220 F. This temperature was maintained until the reaction was complete, which in this case was about forty-five minutes. The completeness of the reactionmay be readily determined by the cessation of the evolution of hydrogen chloride gas. The temperature at which the condensation reaction may be carried out may vary considerably, but preferably should not exceed 300 F. The amount of aluminum chloride used was 10% by weight based on the resin. The amount ofaluminum chloride used may vary between wide limits, but in general it is preferred 'to use approximately 2% to 10% by weight of aluminum chloride based on the resin. The condensation reaction was carried out under conditions of constant agitation in carbon tetrachloride which functioned solely as a solvent to diminish the viscosity of the mixture. When the reaction was complete, insoluble reaction products were removed by water washing. The reaction product was readily separated from the carbon tetrachloride by fractional distillation." The proportion of hydrocarbon resin to chlorinated petrolatum which may be used may be varied between rather wide limits. In general it has been found that most satisfactory results were obtained by using be made therein without departing from the spirit of the invention.

We 'claim: 1. A lubricant comprising a major portion of hydrocarbon oil and a minor portion of hydrocarbon resin-halogenated hydrocarbon condensation product, said hydrocarbon resin having been obtained from partially spent decolorizing adsorbent.

2. A lubricant comprising a major portion of v hydrocarbon oil and a minor portion of hydrodensation product of chlorinated parafiinic hydrocarbon and hydrocarbon resin obtained from partially spent decolorizing adsorbent.

6. Lubricant in accordance with claim 5 in which the resin is obtained from partially spent decolorizing adsorbent which has been used for decolorizing residual petroleum oils.

7. Lubricant in accordance with claim 5 where the condensation product is present in the proportion of about 0.1% to 10%.

8. Lubricant in accordance with claim 5 where the chlorinated paraffinic hydrocarbon is chlorinated petrolatum.

9. A lubricant comprising a major portion of hydrocarbon oil and a minor-portion of condensation product of chlorinated paraflinic hydrocarbon containing approximately 10% to 25% chlorine and hydrocarbon resin obtained from partially spent decolorizing adsorbent.

proportion of about 0.1% to 13. A lubricant additive useful in reducing the pour test of relatively high pour test lubricating oils comprising the condensation product of halogenated paraflinic hydrocarbon and hydrocarbon resin obtained from partially spent decolorizing adsorbent.

14. Product in accordance with claim 13 where the parafiinic hydrocarbon is chlorinated.

15. A lubricant additive useful in reducing the our test of relatively high pour test lubricating oils comprising the condensation product of chlorinated petrolatum and hydrocarbon resin obtained from partially spent decolorizing adsorbent.

16. Product in accordance with claim 15 where the chlorinated pertolatum contains approximately 10% to chlorine.

17. Method oi! preparing a pour depressant comprising chemically reacting halogen with hydrocarbon, mixing the halogenatedhydrocarbon with hydrocarbon resin obtained from partially spent decolorizing adsorbent and a condensation agent, heating the mixture'to elevated temperature and maintaining the temperature for a sumcient time to effect condensation of the halogenated hydrocarbon and hydrocarbon resin and hydrocarbon with hydrocarbon resin obtained from decolorizing adsorbent which has been used to decolorize petroleum oils, and a condensation agent, heating the mixture to elevated temperature and maintaining the temperature for a suiiicient period of time'to eiiect condensation of the chlorinated hydrocarbon and hydrocarbon resin and separating the condensation product from the reaction mixture.

20. Method in accordance 'with claim 19 in which the mixture is heated to a temperature of approximately 200 F. for about forty-five minutes.

21. Method in accordance with claim 19 where the paraffinic hydrocarbon is petroleum wax and the proportion of hydrocarbon resin to chlorinated wax in the condensation product is ap proximately 3 to 2.

22. A lubricant additive useful in reducing the pour test of relatively high pour test lubricating oils comprising the condensation product of halogenated hydrocarbon and hydrocarbon resin obtained from partially spent decolorizing adsorbent.

23. A lubricant additive comprising the condensation product of chlorinated hydrocarbon and hydrocarbon resin obtained from adsorbent clay which has been used for decolorization of Pennsylvania type lubricating oil stock.

24. Additive in accordance with claim 23 where the hydrocarbon resin is obtained from the adsorbent clay by extraction with chloroform.

25. Additive in accordance with claim 23 where the hydrocarbon which is chlorinated is petroleum wax.

26. Additive in accordance with claim 23 where the hydrocarbon which is chlorinated is petroleum wax and the hydrocarbon resin is obtained from the adsorbent clay by extraction with chloroform.

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