US2560547A

US2560547A - Method of processing lubricating

Info

Publication number: US2560547A
Authority: US
Publication date: 1951-07-17
Anticipated expiration: 1968-07-17

Description

Patented July 17, 195i w OIL BY TREATING WITH sULFURIo ACID, A PHOSPHORUS. SULFIDE AND "A BASE AND THE RESULTING PRODUCTS J 1 1. D. Bartlcson, East Cleveland, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio,

acorporation of Ohio No Drawing. Application May 29, 1948,

$erial No. 30,207

18. Claims. (01. 25,232..

This invention relatesto processes of. improving hydrocarbon base lubricants, and more particularly to the treatment of hydrocarbon lubricants with sulfuric acid, then with a small amount of a phosphorus sulfide, and following this by the treatment thereof with a base, and including a.

clay treatment, to formlubricants having. im-

proved properties, especially as to corrosion,

thetically prepared or which maybe derived. from.

natural sources, such as petroleum. For many purposes so-called. additives? mustbe. included with the hydrocarbon in order to. provide a lubris cant having suitable characteristics. This is especially soin. the case of acid. refined oils. with detergent properties.

Generally. the inclusion. ofv

The treatment of the hydrocarbon oil with sul furic acid may be carried out in the conventional these additives is associated. witha higher cost. of

the finished lubricant. The preparation. of afine ished. lubricant. directly from hydrocarbon stock. by a chemical finishing; or refining process (which does not involve solvent-refining or a detergent additive) at a. commercially interesting cost. has been a particularly baffiing: problem. to the art.

In, accordance with. the. invention, it. has. been. found that hydrocarbonlubricating; oil stock may be refined by treatment with sulfuric acid. inthe conventional manner, andthenfurther refined by treatment withasmallamount of a phosphorus sulfide, and. following this with a metaljor nitro.-.

gen base treatment; and the resulting refined productis animproved; lubricant; i. e., a chemical finished. or refined. lubricant. A separate clay. treatment step is included in. thefiprocess at. a. stage. after the sulfuric acid refining step, preferably before. the phosphorus sulfide refiningv step.

Such lubricants ar su able vfor us manner, e. g., using from 1 to 100 lbs. of acid per barrel of oil, at a treating temperature in the; range of 32 to 300 F. A sludgeror acid layer is. removed. This step, has been long and well:- known in the art.

The further refining of the resulting hydrocarbon oil with the phosphorus sulfide may be conducted with direct admixture, or, ifv desired, by their admixture in the presence of a diluent which; may be subsequently removed. Generally a diluent is not necessary. The reaction or treatment is usually complete. in about 10 hours or less time, generally 1 to 2 hours. lhe treating time is a. function of the temperature, the amount of sul:-- fide that is to react, the subdivision of the re.- actants, the efficiency of mixing the reactants, and the like.

The hydrocarbon lubricant stock is reacted with the phosphorus sulfide in a ratio of from about 0.1 to about 0.75% by weight, based on the weight of the hydrocarbon stock, desirably about 0.25 to about 0.6%, and preferably about 0.4 to 9.5%. If:- a higher amount of the sulfide is used, such as 1 some of the characteristics of the resulting, prod-- uct a Worse th n t e i i l oca bon o especially the viscosity increase. At. least 0.1% of the sulfide should be usedto achieve the results desi n a comm i i ltho g mall amounts show improvement.

The treatm n of t h dr c rb n w t t ph r s' u fi-d m e carr ed o t in h rmoen e r a s ce of a r r in a o he 9iinert Q n -deleteriou $3. 5. 1 a tr gen-o H I may a e ar ou u r ress re.

e. g., pressure of theinert gas or that generated he t e re ot o soa r od ou in a o d v e The su de t ating tem er ur varies w th he yd ocarbon toc ene a y the emp ature should be atleast 275? F., but should be below the temperature at which the reaction product would b d m o e A tem r t re in ho ran e of abo 36 i aboi i 4 F- is Pr f rred in many cases. The treated oil, before or after conversion to a base derivative or both, may be centrifuged or filteredtp'remove any by-products, sludge, or other .by-product material. If a volatile diluent is used, is may be removed by evap-1 oration. t l

T a d an s lfid refin d o l s ext trea ed with a base derivative, such as a metal compound.

The metal base may be one or more metal compounds, such as their sulfides, oxides, hydroxides, carbides and cyanamides. The preferred metals are group I, group II and group III metals of the periodic table, such as potassium, zinc, barium and aluminum. For particular services, the heavier metals have particular use, i. e. those below zinc in the electromotive series, such as chromium, cadmium, tin, lead, antimony, bismuth, arsenic, and the like. The alkali and alkaline earth metals are preferred and of these potassium has been selected for the examples in order that they may all be comparative.

In the preparation of the above type base derivatives, the treatment with the base may be carried out at temperature in the range of about 100 to about 350 F., a temperature in the range of about 180 F. to 250 F. being preferred.

From about 0.25 to about 6.0 equivalents of the metal compound may be used per mol of the sulfide used in the sulfide treatment, preferably about 1.0 to about 3.0 equivalents. An equivalent is the quotient of a mol divided by the valence of the metal concerned.

. The hydrocarbon lubricant stock to which the process is applied may be a raw oil, e. g., a fluid hydrocarbon having a viscosity at 100 F. of to 500 centistokes such as that used in S. A. E. 10 to 50 oils. It may be obtained as a distillate or from synthetic material, such as petroleum, and oils produced by cracking, polymerization, hydrogenation, and the like methods.

In order to illustrate and point out some of the advantages of the invention, but in no sense as a limitation thereof, the following specific embodiments are included.

In these examples the hydrocarbon stock is a conventional Mid-Continent lubricating oil base stock, of -30 S. A. E. viscosity (#300 Red Oil). It is treated with sulfuric acid (10-15 lbs. of 93% acid per barrel of oil) in a conventional manner, and the sludge or acid layer is separated. The phosphorus sulfide is mixed with the acid refined hydrocarbon lubricating oil, in the amounts indicated in the following table, and agitated for 1 hour at 300 F. at atmospheric pressure. Then it is mixed with the amount and kind of base (based on the weight of the hydrocarbon" stock) indicated in the following table, and agitated for 2 hours at 250 F., at atmospheric pressure. A good yield is obtained, based on the hydrocarbon lubricating oil, and no sludge is formed. However, it is preferred to filter the final reaction product.

In Examples 1, 2 and 3, the hydrocarbon oil used was obtained from #300 Red Oil, by treating with 10-15 lbs. of 93% sulfuric acid, and allowed to settle overnight; portions of the hydrocarbon layer thereof were used in these examples. In Examples 4, 5 and 6, the Red Oil was similarly acid treated and settled, and then the hydrocarbon layer was separated and treated with 8 lbs. of clay per barrel of oil; portions of this oil were taken prior to filtration and used in these examples. The oil used in Examples '7, 8, 9, 10, 11 and 12 was similarly treated, but the portions were taken after filtration. In Examples 13, 14 and 15, #225 Red Oil was used (a similar oil to the above, but of 20 S. A. E. viscosity), which was similarly acid treated, then clay treated and filtered. The oil was treated with the kind and amounts of phosphorus sulfide, and then base, as indicated in the following table. The preceding, or subsequent, or both separate 4 clay treatments are also indicated. The reac tion product is identified hereinafter by the example number.

Kind and Amount cm in Exam 18 Clay in of Phosphorus Kind and f g pounds per Sulfide in Per Amount of H barrel er barrel oil Cent by Weight Base p oil of Hydrocarbon O 0.2% P 55 and 0.2% Pisa.

The Sohio corrosion test was used in evaluating lubricants made in accordance with the invention. This test is described in a co-pending application of E. C. Hughes, J. D. Bartleson, M. L. Sunday and M. M. Fink, which also correlates the results of the laboratory tests with a Chevrolet engine test.

Essentially the laboratory test equipment consists of a vertical thermostatically heated glass test tube (45 mm. outside diameter and 42 cm. long), into which is placed the corrosion test unit. An air inlet is provided for admitting air into the lower end of the corrosion unit in such a way that in rising the air will cause the oil and suspended material therein to circulate into the corrosion unit. The tube is filled with an amount of oil to be tested which is at least suificient to submerge the metals being tested.

The corrosion test unit essentially consists in a circular relatively fine grained copper-lead test piece of t? O. D., which has a 4" diameter hole in its center (i.e.,shaped like an ordinary washer). The test piece has an exposed copper-lead surface of 3.00 sq. cm. Of this surface area, 1.85 sq. cm. acts as a loaded bearing, and is contacted by a part of the cylindrical surface of a hardened steel drill rod (14 diameter and at" long, and of 51-57 Rockwell hardness) The drill rod is held in a special holder, and the holder is rotated so that the surface of the drill rod which contacts the bearing sweeps the bearing surface (the drill rod is not rotated on its own axis and the surface of the drill rod which contacts the bearing is not changed).

The corrosion test unit means for holding the bearing and the drill rod is a steel tubing (15" long and ln g" O. D.) which is attached to a support. A steel cup 1" long, 1 O. D. by i-" I. D.) is threaded into the steel tube, at the lower end. The cup has a diameter hole in the bottom for admitting the oil into the corrosion chamber. The copper-lead test piece fits snugly into the steel cup and the hole in the test piece fits over the hole in the steel cup. A section of steel rod in diameter and 19" long) serves as a shaft and is positioned by 2 bearings which are fixedly set in the outer steel tubing, one near the top and one near the lower (threaded) end thereof. Several holes are drilled just above and just below the lower bearing. The holes above the bearing facilitate cleaning the apparatus, while the holes below the bearing enable the circulation of oil through the corrosion chamber. The drill rod holder is connected to the shaft byascents a. selfealiening yo e and pin g u li i i Th s a sures instantaneous, and cont nuous ieom t 01? t e drill rod bearing member a ains the b ,e surface at all times. A pulley is fitted to the top ofthe steel shaft and the shaft connected therethrough to a power source. The shaft rotated at about 5 R. P. and he Weig t of the shaft and a tached memb rs is a out 130 rams. Which is th ravi at o al for e which rep.- resent the thrust on the h arin T e ai hit from the air inlet pumps t e o th ough he hamber conta n ng the test p ece and throu h, the holes in th ste l tub n ratios of surfa e act e m ta to t e vo me ofoil an nt na combust n. its; n: ine are ne rly quant tatively u licated in the test e u ment- The tsmnsra urc us d. s a proxim te y tha of the ea in su ace, The rate o air fl w r volume o o l a u ted to t e same as. th average fo te t e i e n oocr: atiou- Of he ata y ic iicots th se due t .9.1 uble iron are the. most important. They are empirically duplicated by the addition oi a soluble Those due to. lead trciniss d1 pli dit' p ocedu e q by r ducin the us al 1 pint Q11 asa ticne ha e im at 4. our ntervals to z pint addit ons- Tiii n siifi on n'creases hessvre ity oi tir test i s. and. dst is ney com on nts. particular y in. the ca e border ino oilsl ach, test. the lass sar s ar cleane b the usual chromic acid method, rinsed and dried. ire metal Harts ar Wastes with. chloro orm an carb n. disuliislc, a d. 19911 has w th NQ- s. cloth or steel W001. A new coigpctrlcad te s t I3.

found to correlate with the Chevrolet procedure 36-hour test are shown in the following table.

' bla 4. Temperature325. Oil sample107 cc. Air flow r'a.t e-,-'7-Q liters/hour Timehours Qatalysts Steel; copper-lead bearing: 3 sq. cm. r a f wh ch 1- om. s a. ocatin surf e: ferric Z-ethyl hexoate: 0.05% as FezQq in C, E benzene; lead bromide: 0 as preci itated p wd EQEWE. as mb Loa est t Q trees P 6.7 5.

By, extending the laboratory test to hours. it was found that correlation with the. Chevrolet 72-hour test could be obtained.

At the close. of the test period, the extent ofcorrosion is. determined byreweighing the 001:5 rosion test piece and determining the change in weight due to the test. An accurate eyaluation of the laoquering properties of an oil is obtained by a visual rating system which is applied to the outer surface of the corrosion unit steel tube and metal cup in much the same way that the piston skirt, cylinder wall, etc. of an engine are rated for varnishes. The sludge rating of the engine is simulated by a visual rating of the insoluble materials and used oil which are coated on the lass test tube at the conclusion of the test. For both sludge and varnish rating a scale rating of A (best) to F (worst) is used.

A sufficient volume of used oil is obtained from, the test for determination of the usual used oil properties, such as pentane insolubles (sludge). viscosity increase, neutralization number and op.- tical density.

The term optical density, as used in the pres: ent disclosure, represents the standard logarithmic ratio of intensity of an incident ray falling on a transparent or translucent medium to the in tensity of the transmitted ray for a sample length of one meter and light of wave length from 5100 to 5500. Angstroms.

The data. in the following tables typify the re, sults obtained in 20-hour Sohio" corrosion tests on hydrocarbon lubricating oil base stock, andthe improved lubricants prepared therefrom in accordance with the invention.

Table I s. A. E. Lubricant Example No... 20-30 1 2 3 4 5 H. -'l a. \,q-\- i A a r V Corrosion of Cu-Pb (in mg ns. weight loss of... 28. l 3.0 3.8 5. 2 7. 5 4:9 Viscosity.LncrcaseKSUS)" 'L 938 217* 93 72 Bentane Insolublcs (in 895 200 222 213- 212 2 17 ncidNi i iribe'rfl; 5S9 1. 1. 1; t l s Sludge a'ting. i Lacquer Rating" E O C 0+ 0- 0 Optical Dnsit 260- 86.7 66. 4 77.9 86' 71. as; Con en (pe 0- 0- 0 274 9 38 45 t '26 e 7 a 9 10 Lub i ntExam leNo (Blank) Corrosion of Ou-Pb (in mgms. Weight loss of). 28. 1 6. 6 6.1 7. 6 7. 9 9. 2 Viscosity Increase (SUS) 938 17 64 141 134- Pcntane Insolubles (in m 895 152- 177' 173 209 Kc N iiinb'eil. 5539 k2 I}? 0.433 Sludge Rating. V v Lacquer Rating E- O- D O- D D'fificiiPDmMty-.. 260 103 106 146 134 16,4 Ash C nt nt (per cent by g t gssuliat 9.0 .5? 0.39 0.69 0 57 0- Table III Lubricant-Example No kfi gkf 13 14 16 Corrosion of Ou-Pb (in mgms.

weight loss of) 151. 8 7.1 6. 5 4. 2 Viscosity Increase (SUS) 1,390 100 124 62 Pentane Insolubles (in mgm g.

of lubricant) 1, 395 99 118 68 Acid Number 5. 2 0. 74 1. 04 0.80 Sludge Rating E A- A- A Lacquer Rating D A A A Ash Content (per cent byw ght, as

L sulfate) 0. 0 062 018 258 The above data show that the reaction products of the invention are clearly superior lubricants to the blank oil, and the great improvement in corrosion, viscosity increase, and 'pentane insolubles is especially noteworthy. Example 1 (one clay treatment as last step)- showsespecially low corrosion; Example 6 (two clay treatments) shows especially low viscosity increase; and Example 15 (one clay treatment before the phosphorus sulfide refining step) shows especially low pentane insolubles.

A similar example in which the oil is treated simultaneously with sulfide, KOI-I and clay shows the unsuitability of this method because of high viscosity increase. A subsequent and separate clay treatment raises the viscosity increase. Simultaneous clay and sulfide treatment followed by KOI-I'treatment is not satisfactory. These examples demonstrate the necessity of the steps recited in the order specified.

The 36-hour L-4 Chevrolet engine test was also used in comparing the oils of Examples 5, 6, 8, '11 and 12. In this test, new piston rings and two new copper-lead bearing inserts are installed in the motor prior to each test. The engine is a conventional Chevrolet engine with 216.5 cu. in. piston displacement and a compression ratio of 6.5 to 1. The engine is operated at 3150 R. P. M. with a load of 30 B. I-L'P. and at a temperature at the jacket outlet of 200 F. The lubricating oil temperature is maintained at 265 F. for an S. A. E. 10 grade oil, and at 280 F. for oils of S. A. E. 30 to 50 grades. The fuel used contains from 2.5 to 3.0 ml. of tetraethyl lead per gallon] Besides the weight loss of the test bearings, deposits in the power section, and properties of the used oil, sampled near the middle and also at the end of the test, are examined. The following results were obtained.

Table IV LubricantExample N o 5 6 8 11 12 Overall Rating 68.75 80.50 86. 2s 84. 2a 93. 50 Bearing Corrosion (rngms/ 7 bearing half-shell) 74 70 176 232 Viscosity Increase (SUS) -24 38 -72 80 63 Pentane Insolubles (in per cent by weight of the oil) 3. 84 2.04 1.89 2. 73 2.66 Acid Number 2. 2 0.97 1.55 1. 45 0.89

By comparable procedures, using any known comparable phosphorus sulfide, or amount of phosphorus sulfide, or hydrocarbon lubricating oil stock, within the broad types and ranges as indicated hereinbefore, comparable improved lubricants are obtained.

If desired, the improved lubricants of the invention may be used in blends together with other lubricants or lubricant agents, e. g., with soap or the like in a grease. If desired, an agent for improving the clarity of the oil may be included, e. g., lecithin, lauryl alcohol, and the like. If desired,- an agent for preventing foaming may be included, e. g., tetra-amyl silicate. an alkyl ortho-carbonate, ortho-formate or ortho-acetate, or a polyalkyl silicone oil.

In view of the foregoing disclosure, variations and modifications of the invention will be apparent to those skilled in the art, and it is intended to claim such variations and modifications broadly, except as do not come within the scope of the appended claims.

I claim:

1. A method of processing lubricating oil stock consisting essentially of hydrocarbon material to yield an oil having improved inhibition to oxidation in service, whch method comprises treating said stock with sulfuric acid in a conventional manner, then treating the resulting acid-refined hydrocarbon with an amount of a phosphorus sulfide in the range of about 0.1 to about 0.75% by weight at a temperature in the range of about 275 to 450 F., then with an amount of a base in the range of about 0.25 to 6.0 equivalents per mol of the sulfide, and including at least one separate clay-treating step subsequent to the acid-refining step.

2. The method of claim 1 wherein the phosphorus sulfide is phosphorus pentasulfide, and the base is a metal base.

3. The method of claim 1 wherein the claytreating step is just prior to the phosphorus sulfide treating step. I

4. The method of claim 1 wherein an amount in the range of about 0.25 to about 0.6% of phosphorus sesquisulfide is used as the phosphorus sulfide and the treatment therewith is at a temperature of about 300 to 450 F. I

5. The method of claim 4 wherein the claytreating step is prior to the phosphorus sesquisulfide treating stepgand an amount of potassium hydroxide in the range of about 0.1 to about 1.0%

is used as the base.

6. The method of claim 4 wherein an amount of potassium hydroxide in the range of about 0.1

. .to about 1.0% is used as the base, and the claycorrosion; and this data indicates that this ratio of P2155 and KCH is particularly desirable.

7 claim 4.

treating step follows the base-treating step.

'7. The method of claim 3 wherein the phosphorus sulfide is phosphorus pentasulfide, and

the base is a metal base.

8. The method of claim 7 wherein the claytreating step is subsequent to the metal base treating step.

9. The method of claim 8 wherein an amount in the range of about 1.0 to 3.0 equivalents of potassium hydroxide is used as the base.

10. A lubricant obtained by the process of claim 1.

11. A lubricant obtained by the process of claim 2.

12. A lubricant obtained by the process of claim 3.

13. A lubricant obtained by the process of 14. A lubricant claim 5.

15. A lubricant claim 6.

16. A lubricant claim 7.

17. A lubricant claim 8.

18. A lubricant claim 9.

9 obtained by obtained by obtained by obtained by obtained by the the

the

DIOCESS process process of 5 process process JOHN D. BARTLESON.

10 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Petroff Feb. 17, 1914 White Apr. 6, 1943 Musselman Jan. 22, 1946 Hughes Apr. 16, 1946 Noland Apr. 29, 1947

Claims

1. A METHOD OF PROCESSING LUBRICATING OIL STOCK CONSISTING ESSENTIALLY OF HYDROCARBON MATERIAL TO YIELD AN OIL HAVING IMPROVED INHIBITION TO OXIDATION IN SERVICE, WHICH METHOD COMPRISES TRATING SAID STOCK WITH SULFURIC ACID IN A CONVENTIONAL MANNER, THEN TREATING THE RESULTING ACID-REFINED HYDROCARBON WITH AN AMOUNT OF A PHOSPHORUS SULFIDE IN THE RANGE OF ABOUT 0.1 TO ABOUT 0.75% BY WEIGHT AT A TEMPERATURE IN THE RANGE OF ABOUT 275* TO 450* F., THEN WITH AN AMOUNT OF A BASE IN THE RANGE OF ABOUT 0.25 TO 6.0 EQUIVALENTS PER MOL OF THE SULFIDE, AND INCLUDING AT LEAST ONE SEPARATE CLAY-TREATING STEP SUBSEQUENT TO THE ACID-REFINING STEP.