US2833720A

US2833720A - Organophilic bentonite bodied lubricant containing a nitroparaffin

Info

Publication number: US2833720A
Application number: US453721A
Authority: US
Inventors: Charles A Stratton
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1954-09-02
Filing date: 1954-09-02
Publication date: 1958-05-06
Anticipated expiration: 1975-05-06

Description

May 6, 1958 c. A. STRATTON 2,833,720

, ORGANOPHILIC BENTONITE BODIED LUBRICANT CONTAINING A NITROPARAFFIN Filed Sept. 2. 1954 N/ TQOBENZE/YE IV/ TROPROPAA E 2/V/ TPOPPOPA/VE MTAWME TIM/V! PER (EN T OISPERSANT INVENTOR; C A. Jtra ttan WM Arrow/El a "obtain a gel or grease.

United States ORGANOPHILIC 'BENTONITE BODIED LUBRI- CANT CONTAINING A NITRQPARAFFIN Charles A. Stratton, Caney, Kans., assignor to Phillips Petroleum Company, a corporation of Delaware Application September 2,1954, SerialNo. 453,721 I 18 Claims. (Cl. 252-495) This invention relates to lubricants. In one of its more specific aspects, this invention relates to bodied lubricants. In another of its more specific aspects, this purpose are the metal salts of long carbon chain saturated and unsaturated fatty acids as, for example, potassium oleate, magnesium stearate, aluminum p'almitate, et'c.,

although salts of aromatic-acids, such as lead 'naph'then'ate,

are also useful. It is commonly observed that lubricants 2,833,720 Patented May 6, 1958 "ice - lithium, and other bentonites, particularly 'of'the Wyomin types; magnesium bentonite (sometimes called hectorite') and saponite; also nontronite and attapulgita particw larly that of the Georgia-Florida type. These clays characterized by an unbalanced crystal lattice, are believed to have negative charges which arenormally neutralized by inorganic cations. As found in nature, therefore, they exist as salts of the weak clay-aci d with bases, such as the alkalior alkaline-earth, metal hydroxides. Bentonites which are particularly useful are, the swelling bentonites of the Wyoming type and the swelling magnesium bentonites of the hectorite'type.

An organophilic bentonite, commonly used in the manufacture of bodied lubricants from mineral. lubrieating oils, is formed by replacing the exchangeable inorganic cations of the bentonite with organic cations from salts of aliphatic, cyclic, aromatic and heterocyclic amines, primary, secondary and'tertiary amines and polyamines, and quaternary ammonium compounds, such as to achieve complete removal of non-clay impurities which would impart an abrasive character to the finished lubricant. The reactive exchangeable inorganic cation, such as sodium or potassium, of the dispersed bentonite is "replaced by the addition of the salt referred to above and'the modified clay is then filtered, washed,'dried and "groundinto a fine powder. Increasing the chain length properties of the modified bentonite.

of an alkyl ammonium cation used to replace the exchangeable inorganic cation increases the 'organophilic A more com- "plete disclosure of the preparation of organophilicbem consisting of these soap-in-oil dispersions have a rela tively high thermal coeflicient of viscosityand that at temperatures often encountered in machinery undernormal operating conditions these greases become fluid, resulting inloss of the lubricant and damage to the inachinery. This is to a considerable extent a function of the melting point of the soap. Thus, the magnesium, zinc,

or aluminum soaps would not be desirable for high temperature applications because of their low melting points.

bodying agents increase the low ternperature consistency to such a degree that starting of cold machinery is diffi l l I One more recently developed type of bodied lubricant ,is one formed by colloidally dispersing an organophilic clay, commonly called bentone, in an organic lubricating "liquid, such as a petroleum lubricating oil, asynthetic lubricating oil, such ,as a diester or heavier :polyester,

or a mixture of suchflubricating oils, in a manner to Theclays which are useful as starting material for making the modified clay in acstantial base-exchange properties, and particularly those exhibiting comparatively high base-exchange properties and containing cations capable of more orless easy retonite will be found in United States Patent 2,531,427,

issued to E. '-A. Hauser.

the invention'is to provide an improved lubricant bodied by an --org'anophilic clay. Another object of the invention is to provide .a lubricant bodied by dispersing an organophilic clay in an organic. lubricating liquid with acetone and a nitroparaflin having from 1 to 3;carbon ing of an organic lubricating liquid with an organophilic bentonite clay in the presence of a nitropara'flin having from 1 to 3 carbon atoms per molecule. The use of such nitroparatnns as dispersion agents results in agrease which has good consistency. However, I have discovered that over and beyond that improvement, the formation "of a gel which has not only good consistency but also H V V -nitr'oethane, 2-nitropropane and l-nitropropane. cordance with this invention are those exhibiting subgood Work stability by dispersion of an organophilic bentonite in an organic lubricating liquid is aided by the addition of a small amount of acetone together with a nitroparafiin selected from the group of nitromethane, The adaptability of the Z-nitropropane and l-nitropropane as a portion of the dispersion agent is dependent upon whether or not the grease which is desired is a relatively soft grease. Furthermore, as will be disclosed hereinafter, a-greater amount ofeach of'the nitropropanes ,is necessary to;-obtain a minimum unworked micropenetration than; is necessary" when using nitromethane or nitroethane. v t Dispersion agents, such as ethyl acetate, acetic acid, acetone, methyl. alcohol, ethyl alcohol, ben zoyl chloride,

butyl ,stearate, coconut oil, cyclohexanone, ethylene dichloride,; ethyl ester, furfuraLisoamyl acetate, methyl ethyl ketone, and nitrober zene,,have been disclosed by the prior art as being 'solvat'ing agents which can be used in creating'an organophilic bentonite claythickenedgrease composition. I; have foundthat the ,,di spersion -o f an organophilic bentonite in ,a lubricating liquidto form. a gel having'goodconsistency, and also good work stability can be facilitated by the use of a combination of acetone and at least one of the nitroparatfins of the group of nitro- The prior art has not suggested the use of such materials as dispersing agents in; the formation of an organophilic characteristics}; I have discovered that the suitability of the alkyl nitro -parafiins is inverseto the number of carbon; atoms in. the alkyl radical- 0f the two nitropropanes, 2-

persion agent than is l-nitropropane, either alone,,:in combinationwith another,. nitroparafiin or in combination with acetone. I o l p 1 Better nnderstandingof this invention willbe obtained tionas contrasted with certain dispersants fromthe prior I The amount of dispersing agent which is utilized in 35 my grease dependentfupon not only theflspecifie dis- 'persing agent, but is also dependent upon the concentration of the organophilic bentonite clay, thetype of that clay, such as .Bentone 18,..Bentone 34,,etc., andrthe the range :of from 2 to 35 percent, depending upon the apesnzo methane, nitroethane, Z-nitropropane and l-nitropr opane.

bentonite. clay thickened greaseicompositionnor has it suggested the use ofcombinations of nitroparaffins and acetone to provide an organophilic bentonite clay thickenedgrease composition having improved work stability nitropropaneis much more adaptable for use as a disspecific lubricating liquid used. In general, the organo- 1 philic bentonite clay is used ina concentration within specific grade of grease desired. The amountpf disperse ing agentwhich is usedyaries above 0.25, weight percent,

generallywithintthe rangeof from 0.25 to 6 percent by weight, the. specific amount oncev again beingdependent upon the bentonite concentration, the-type of organow philic bentonite clay used and the lubricating liquid useds I havediscovered that the aIkyInitrOparatfins having from g l to 3 carbon atoms per molecule can be used in the above concentrations If desired, they can be used in combination. Ihavefurtherdiscovered thatnitroparaffins having from 1 to 3 carbon atoms per molecule, and particu larly nitromethane or nitroethanqcan be utilized in admixture with acetone which is'a conventional dispersion agent for anorganophilic bentonite clay, so as to obtain o a grease which has a better consistency than 'does a grease, which is formed utilizing, acetone in an a sum equal :to the total amountof the mixture bf. acetone and ,nitroparaflina I have found that an. improved organophilic bentonite clay type grease can.beformed whenyusing at least t) .25 percent byqweight total dispersants When ,a

mixture of, acetone and a- .nitroparafhn is. used. as the dispersant in amounts within the range set forth above,

the grease is improved when the nitroparalfin, preferably I nitromethane or nitroethane,;is present in anfamount of at least 0.05 percent by weight.

q i The bodied lubricant. is formed from .an organic'lubricating liquid, such as. petroleum mineral oil, polyesters,

silicone oils, and .thelikqyvhen using one or more of these alkyl nitroparaflins alone or in combination with acetone as a dispersion agent. Outstanding properties of bodied is. improved by the use at parafiins as a part of the dispersion agent.

at least one of the alkyl nitro- The preparation of a bodied lubricant from an organophilic bentonite clay in a lubricating liquid is a rather simple operation which is accomplished by thoroughly mixing the lubricating liquid and the organophilic bentonite clay with a dispersion agent. In some instances, it is advantageous to heat the mixture or work the mixturein a milling operation, However, such steps are not always necessary.

In the preparation of a grease of the instant invention, it is preferred to use a lubricating oil, such as a mineral lubricating oil, a polyester oil, or a silicone fluid, which is oxidant resistant. The selection of the specific type of oil for use in this grease depends to a large extent upon the temperatures at which it is to be used. Oils which contain aromatics, as shown by low viscosity indiccs, produce greases which give higher consistencies at lower temperatures than do oils of lesser aromatic content with higher viscosity indices. When greases are to be used at high temperatures, however, high viscosity oils are preferably utilized for the reason that less heat breakdown is encountered with the, use ofsuch oils. Polyester oils and silicone fluids are particularlyuseful in the production of greases to be used at high temperatures, as such oils are particularly heat-resistant.

The dispersion of organophilic bentonite clay in the oil phase may be accomplished rather easily while using a cold oil. The dispersion can be made even more readily, however, by heating the oil to a temperature below its decomposition point but preferably to a temperature but slightly above atmospheric temperature.

Minor proportions of conventional oxidation inhibitors, such as mercaptoaryl thiazoles, aminophenols, phenylene diamines, and phenyl-a-naphthyl amine, may be incorporated in the grease for the purpose of improving the oxidation resistance of the oil base.

. The percentage of organophilic bentonite clay which may be 'used to produce a satisfactorynlubricant of this invention usually lies in the range of 2 to 35 weight percent based on-the finished lubricant. I prefer to use clay load- EXAMPLE I Bodied lubricants of similar compositions were prepared from several different petroleum mineral oil stocks and including minor proportions of acetone or nitromethane. Given quantities of commercial grade dimethyl dicetylammonium bentonite (Bentone 34), an organophilic bentonite clay available from the National Lead Company, were mixed with small quantities of selected petroleum mineral oil lubricating blending stock to form a slurry and minor amounts of acetone .or nitromethane were added to selected mixtures. Additional lubricating blending stock was then added at room temperature to form a bodied lubricant. After thorough mixing,.the admixture was milled in a Navy grease worker using a worker plate containing 0.06 inch holes for 1000 strokes. The bodied lubricant was then de-aerated for ten minutes under a mechanical vacuum to remove the entrained air bubbles. These lubricants were then tested with a penetrometer, as described in ASTM Test D-217-44T, but modified so as to use a micropenetrometer needle, plunger and cup as described by Kaufman, Finn, and Harrington in Industrial and Engineering Chemistry," Analytical Edition 11, 1081l0 (1939). The lubricant composition and'micropenetrations are set forth below inTable I.

ama am Table I "Bentone 34" 7.0 7.0 20 Lubricating oil blending stock 91. 5 91. 5 Nitrnm ath am: i 1. 5 Acetone 1'. 5

Micropenetration 105 S4 "Bentone 34"". 5.0 5.0 250 Lubricating Oil blending stock 93. 5 Nitromethane 1. 5 Acetone Mieropenetrationn'nfl 193 183 Bentone 34" 7.0 7. 0 200 Lubricating oil blending stock 91. 5 91.5 Nitrmnethane- 1. 5 Acetone 1. 5

Mlcropenetration 382 319 As shown by the penetration tests, the bodied lubricants prepared with nitromethane as the dispersant, have greater consistency than the bodied lubricants of similar composition prepared with acetone as the additive material. V

EXAMPLEII 5.25 grams of Bentone 34" were slurried into 25.0 grams of 20 lubricating oil blending stock. 1.12 grams of ethyl acetate were added, and the mixture was stirred until a gel was obtained. The gel was weak, having a micropenetration, obtained as disclosed in Example I, of 356. The Bentone" content of this grease was higher than is commercially'feasible, and when additional oil was added to the grease to bring the Bentone content "down to a reasonable value, the gel broke up completely.

EXAMPLE III Two greases were prepared by stirring Bentone 34 into a 20 lubricating oil blending stock until a smooth Grease 1 Grease 2 Micropenetration Therefore, as shown by these data, the grease prepared by using nitromethane as a dispersant had a better temperature resistance than the one using acetone as the dispersant.

EXAMPLE 1v Several comparative greases were formed in the following manner. 5.2 grams of Bentone 34 was added 'to 92.5 grams of 20 lubricating oil blending stock. The Bentone 34 was allowed to become wetted by the on and settle therein. The mixture was thereafter stirred in a mixer for five minutes to efiect a uniform slurry. Nitromethane was added to the slurry and the slurry was thereafter mixed for a period of five minutes. Acetone was then added and the mixture was stirred for thirty minutes. The mixture was then milled in a Charlotted mill, model ND-l with a three horse-power motor and a T-grooved rotator and stator at 0.003 inch clearance and 257 ml./ min. T he same procedure was utilized in forming greases using only nitromethane or acetone as the dispersion agent, except that the mixtures in those cases was stirred for a total of thirty minutes to obtain thorough mixing. Work stability of the greases was determined and the results are set forth below in Table III.

-Bentoi ie'34" Acetone A. S. '1. M. Standard Penetrations:

Table III NLGI grade one grease has a 60 stroke penetration limit within the range of between 310 and 340. It will be noted that neither the grease utilizing nitromethane alone or the grease utilizing acetone alone falls within the required limits of the grade one grease. I have determined that for a grade one grease, it is necessary to utilize from 1.2 percent to 1.7 percent of acetone and from 0.8 percent to 0.3 percent nitromethane, respectively, when a total of two percent dispersion agent is utilized in order to meet the requirements for NLGI grade one grease. As the amount of nitromethane in the grease was decreased and the amount of acetone was increased, a softer grease was obtained.

Table II Grease 1 Grease 2 6 20 Lubricating oil blending stock 732 G 732 G. Bentone 34 66 56 Acetone 12 Nitromethane 12 Micropenetration 109 79 A sample of each of these bodied lubricants was heated on a hot plate in a 50 milliliter beaker. The two samples were heated side by side on the same hot plate and the temperature of each was determined by means of a ther- Although the above examples have been specifically drawn to the use of nitromethane and acetone as dispersion agents, additional data have been obtained showing the comparative usefulness of nitroethane, 2-nitropropane, and lanitropropane, in comparison with two additional dispersing agents of the prior art. Those two additional prior art dispersing agents are methyl cellosolve and nitrobenzene. As will be apparent from the attached drawing, greater amounts of the nitropropancs are requiredto disperse 7 ,weight1percent Bentone 34 in20 lubricating oil blending stock.

Various modifications of this invention will be apparend to those skilled in the art. Such modifications are believed tube within the spirit and the scope ofthis invention asset forth in this disclosure.

Iclaim: 1 t I 1. A bodied lubricant comprising an organic lubricating liquid; a sufiicient amount of an organophilic ,bentonite clay to thicken said lubricating liquid to a grease consistency; and an amount of a mono-nitroparafiin containing from 1 to 3 carbon atoms per molecule sufficient to disperse said clay.

2. The lubricant of claim 1 wherein said nitroparafiin is nitromethane.

3. The lubricant of claim 1 wherein said nitroparatlin is nitroethane.

4. The lubricant of claim 1 wherein said nitroparaffin is 2-nitropropane.

5. The lubricantof claim 1 wherein said nitroparaflin is l-nitropropane.

6. A bodied lubricant comprising between 65 and 97 weight percent of an organic lubricating liquid; between 2 and 35 weight percent of an organophilic bentonite clay, and between 0.25am! 6 weight percent of a mono-nitroparaffin containing from 1 to 3 carbon atoms per molecule. g t

7. A bodied lubricant comprisingbetween 65 and 97 weightpercent of an organic lubricating liquid; between 2 and 35 weight percent of an organophilic bentonite clay, and between 0.25 and 6 weight percent of a mixture of "acetone and a mono-nitroparafiincontaining from 1 to 3 carbon atoms per molecule, wherein said nitroparafiin is present in said mixture in an amount of at least 0.05 percent by weight. w

8. A lubricating composition having an organic lubricating liquid base bodied with an organophilic bentonite clay and containing as a dispersant 0.25 to 6 weight percent of a mixture of acetone and nitromethane wherein said nitromethane is present in an amount of at least 0.05 percent by weight.

9. A bodied lubricant comprising between 65 and 97 weight percentof an organic lubricating liquid; between 2 and 35 weight percent of an organophilic bentonite clay, and about 2 percent by weight of dispersant material consisting essentially of nitromethane in the range of from 0.3 to 0.8 percentand acetone in the range of from 1.2 to 1.7 percent by weight.

10. In producing a bodied lubricant by incorporating liquid, the improvement which comprises using'as at least 8 a portion of the dispersant, a mono-ni-troparaflin contain ing from 1 to 3 carbon atoms per molecule.

I 11. A bodied lubricant comprising between and weight percent of an organic lubricatingliquid; between 3 and 15 percent by weight of an organophilic bentonite clay; and between 0.25 and 6 weight percent of a mononitroparaflin containing from 1 to 3 carbon atoms per molecule.

12. A bodied lubricant obtained by dispersing between 2 and 35 weight percent of an organophilic bentonite clay in from 65 to 97 percent by weight of an organic lubricating liquid in the presence of between 0.25 and 6 weight percent of a mono-nitroparaffin containing from 1 to 3 carbon atoms per molecule.

13. A bodied lubricant consisting essentially of an organic lubricating liquid thickened to a grease consistency in the presence of a dispersing amount of a mononitroparafiin containing from 1 to 3 carbon atoms per molecule with between 2 and 35 percent by weight of a complex formed by reacting a bentonite clay with a salt of a material selected from the group consisting of amines and quaternary ammonium compounds.

14. The lubricant. of claim.13 wherein said organic lubricating liquid is thickened in the presence of nitromethane. t

15. The lubricant of claim 13 wherein said organic lubricating liquid is thickened in the presence of nitroethane.

16. The lubricant of claim 13 wherein said organic lubricating liquid is nitropropane.

17. The lubricant of claim 13 wherein said organic lubricating liquid is thickened in the presenceof 1- nitropropane.

18. A bodied lubricant comprising between 65 and 95 weight percent of an organic lubricating liquid; and between 5 and 35 weight percent of an organophilic bentonite, thickened to grease consistency in the presence of between 0.4 and.5 weight percent of nitromethane.

References Cited in the file of this patent UNITED STATES PATENTS 2,662,056 McCarthy Dec. 8, 1953 2,662,057 McCarthy Dec. 8, 1953 2,662,058 McCarthy Dec. 8, 1953 2,677,661 OH-alloran May 4, 1954 OTHER REFERENCES organophilic Bentonites--Swelling in Organic Liquids by JohnJordan, Journal of Physical and Colloid Chem.,.pages 294, 305, vol. 53, No. 2, February 1949.

thickened in the presence of 2-.

Claims

1. A BODIED LUBRICANT COMPRISING AN ORGANIC LUBRICATING LIQUID; A SUFFICIENT AMOUNT OF AN ORGANOPHILIC BENTONITE CLAY TO THICKEN SAID LUBRICATING LIQUID TO A GREASE CONSISTENCY; AND AN AMOUNT OF A MONO-NITROPARAFFIN CONTAINING FROM 1 TO 3 CARBON ATOMS PER MOLECULE SUFFICIENT TO DISPERSE SAID CLAY.