US2516654A - Antioxidants for mineral oil lubricants and compositions containing the same - Google Patents

Description

Patented July 25, 1950 UNITED [STATES M'PATEN/T' I iANTIOXIDANTS FOR CANTS AND'COMPO THE SAME 2,516,654 OFFlCE MINERAL OIL LUBRI- SITION S CONTAIN Herschel G'..Smith, Wallingford, and Troy L. cantroll, Lansdowne, Pa., andJohn G. Peters; Audubon, N. .L, assignors to Gulf Oil Corporation,

Pittsburgh. Pa.,

a corporation of Pennsylvania 7 No Drawing.- Application January 6, 1949,

Serial No. 69,614 g is Claims. (Cl. 252-415 .This invention relates to antioxidants for mineral oil 'lubricants and compositions containing the same, and more particularly, it relates to addition agents for mineral oil lubricants which surfaces of varnish, gum or sludge. I Furthermore,

many'lubricating oil compositions which may be highly satisfactory for the lubrication of other mechanisms have been found wholly unsuitable for use as turbine oils.

The formation of varnishes, gums and sludges on engine surfaces is due at least in part to oxidation effects on mineral lubricating oils. In turbine oils the problem of oxidation is further aggravated, because in normal use turbine oils rapidly become contaminated with water.

It is an object of this invention, therefore, to provide an addition agent for mineral oil lubricants which will'inhibit the oxidative deterioration of such lubricants;

It-is further an object of this invention to provide mineral oil lubricant compositions which are remarkably stable against oxidation under service conditions.

These and other objects are accomplished by the present invention wherein an addition agent for mineral oil lubricants is prepared by con-- densing phenyl morpholine, N-dimethylaniline and formaldehyde in the presence of an activated clay as a catalyst, and recovering the condensation product. The condensation product so obtained isa light-colored product which, when added to mineral oil lubricants, confers a remarkable stability against deterioration by oxidation. Such condensation products and mineral oil lubricant compositions containing them are believed to be novel and are considered parts of our .invention. Contrary to what may be expected from the-nature of the reactants, we do not obtain highly-condensed, insoluble resinous products. When the above reactants are condensed in accordance with our invention, there are obtained light colored condensation products which are non-resinous and which are readily soluble in mineral oils.

In performing the condensation the reactants are mixed and heated to a maximum tempera-- ture of 350 F. We have found that if the temperature of 350 F. is exceeded to any substantial extent, the condensation product formed tends to be resinous and insoluble. In general,

-'the preferred temperature for the condensation ranges from 160 to 220 F.

The proportions of the reactants vary as follows: For eachmol of phenyl morpholine, N-dimethylaniline is employed in an amount of from 2 to 6 mols, and the formaldehydeis employed in an amount from 2 to 6 mols. Ordinarily, it is preferred to use from 5 to 10 per cent by weight of the activated clay catalyst, based on the total weight of the reactants. However, smaller amounts, as low as 1 per cent by weight, and larger amounts, as high as 20 per cent by weight, may also be employed; but larger amounts than about 10 per cent byjweight are ordinarily not necessary.

The phenyl morpholine referredto herein has the formula:

CHr-CH:

In lieu of formaldehyde any formaldehydemorillonite, fullers earth, floridin and smectite,

which has been acid treated in order to activate the clay. These materials are described in U. S. Patent 1,898,165, for example.

In preparing our new addition agents, the reactants and catalysts are placed into a reaction vessel which is then closed and the mixture heated with agitation under reflux until all of the formaldehyde or formaldehyde-yielding compound has been consumed. At this time the water which is formed as a result of the condensation is removed, preferably under vacuum, and the dehydrated condensation product is then filtered to remove the activated clay catalyst. In some instances, it is desirable to prepare our new addition agent in a concentrate in a mineral lubricating oil which may then be diluted down with additional oil to the concentration desired in the final lubricating composition. In such instances, the mineral lubricating oil may be added in a suitable amount, say in a weight equal to the weight of reactants, to the reaction mixture in the reacance with the above disclosure tion vessel. and the condensation product obtained will then be a concentrated solution of the addition agent in the mineral lubricating oil.

The condensation products obtained in accordance with our invention are liquids or crystalline solids. While the exact nature of the chemical composition of the condensation products is unknown, all of the three reactants enter into a final unitary product. The exact nature of the manner in which the catalyst influences the reaction is unknown. However. regardless of any theory involved, the use of an activated clay catalyst is an essential feature of our invention, since if the catalyst is omitted, black, insoluble, resinous condensation products are obtained.

The following examples illustrate the preparation of our new addition agent.

Example I.Into an enamel-lined reaction vessel were charged 163 pounds of phenyl morpholine (1 pound moi), 363 pounds of N-dimethylaniline (3 pound mols), and 243 pounds of a 37 per cent by weight aqueous formaldehyde solution (3 pound. mols of anhydrous formaldehyde) along with 62 pounds of an activated clay (Filtrol) as a. catalyst. The mixture was refluxed and agitated at 280 F. for a period of 5 hours, and then all water, both that added with the formaldehyde and formed in the reaction, was distilled oil. The product was then filtered and had the following properties:

Gravity, API 3.5 Color, NPA 4.75 Neutralization No 1.00

Gravity, API 4.1 Color, NPA 3.5 Neutralization No 0.7

Example III.--Another reaction product was prepared by reacting 1 mol of phenyl morpholine, 3 mols of N-dimethylanilineand 6 mols of formaldehyde in the presence of 5 per cent by weight of the total reactants of an activated clay catalyst under the conditions set forth in Example I. The product had the following properties:

Gravity, API 3.7 Color, NPA 11.0, Neutralization No 0,6

The condensation products obtained in accordfrom phenyl morpholine, N-dimethylaniline and formaldehyde in the presence of an activated clay catalyst are excellent addition agents for mineral oil lubricants. They are readily soluble in all types of mineral oils, that is, parafllnic, naphthenic or mixed base mineral oils in high proportions to form concentrated solutions thereof, which may then be diluted down to the proportions desired in the final mineral oil lubricant composition.

For this purpose small amounts of our new addition agents are generally suflicient For example, our addition agents may be added to mineral lubricating oilsin minor amounts, say

from 0.001 to 1 per cent by weightof the mineral 4 oil, sunlcient to inhibit the oxidative deteriora The following examples illustrate the remark-' able antioxidant effects of our new addition agents. In the following examples, the base oil and the same oil blended withour. new addition agents aresubiected to a standard oxidation test which measures the stability of the oils to oxidation. The oxidation test referred to is a standard test designated ASTM D943-47T. Briefly, the test comprises subjecting the oil sample to oxygen at a temperaturegof C. (203 F.) in the presence of waterand an iron copper catalyst. and determining the time required to--bulld up a neutralization number of 2. The flow of oxygen ismaintained at 3 liters per hour.. dation of mineral oil lubricant compositions containing our new addition agents is illustrated by the results shown in the following examples.

Example IV.To a steam a viscosity of 148 SUV at F. there was added 0.5 per cent by weight of an addition agent prepared according to Example I. The base oil and the oil blended with the antioxidant were then subjected to the above described standard oxidation test with the following results:

hipiotgedmOil on n g 0.5% Antioxidant Gravity API 29.4 29.5 Oxidatio'n Test, ASTM D943-47T 203 F., 3 L Oxygen/Ha:

Time Oxidized, Hrs 180 2, Neutralization No..' g 2.0 2.0.

Example V.'To a motor oil which had been highly refined by aluminum chloride treatment there was added 0.5 per cent by weight of an antioxidant prepared according to Example I. A

The above examples show the remarkable oxidation stability imparted to mineral oil lubricant compositions by the use of our new addition agents. Mineral oil lubricant compositions containing our new addition agent are therefore eminently suited for use where the operating conditions are extremely severe, as in Diesel, tank and truck engines, and in the lubrication of steamturbines.

The remarkable effects of our new addition agents cannot be readily accounted for and cannot be predicted from the nature of the reactants. Thus, condensation products prepared from other functionally similar compounds have been found to be either prooxidant or to show no antioxidant effects whatsoever. For example, we have prepared a condensation product similar to our new addition agent by substituting xylidine for the N- dimethylaniline. The resulting condensation product was'found to be entirely unsuitable for The remarkably effective stability to oxiturbine oil having 1 our invention is not limited thereto but comprises all mineral oil lubricant compositions containing our new addition agents, such as greases and the like.

Resort may be had to such modifications and variations as fall-within the spirit of the invention and the scope of the appended claims.

We claim.

1. The process of preparing an addition agent for mineral oil lubricants which comprises heating phenyl morpholine with from 2 to 6 mols of N-dimethylaniline and 2 to 6 mols of formalde hyde per mol of phenyl morpholine in the presence of an activated clay catalyst at a temperature not in excess of 350 F. to condense together the three reactants, and recovering the condensation product.

2. The process of preparing an addition agent for mineral oil lubricants which comprises heating phenyl morpholine with from 2 to 6 mols of N-dimethylaniline and, 2 to 6 mols of formaldehyde per mol of phenyl morpholine inthe presence oi 5,to 10 percent by weight of the total reactants of an activated clay catalyst at a temperature of from 160 to 220 F. to condense together the three reactants, and recovering the condensation product.

3. The process of preparing an addition agent mmineral oil lubricants which comprises adding an activated clay catalyst, phenyl morpholine with from 2 to 6 mols of N-dimethylaniline and 2 to 6 mols of'formaldehyde per mol of phenyl morphoiine to a mineral lubricating oil, heating the mixture to a temperature not in excess of- 350 F. to form a condensation product. and recovering a solution of the condensation product in the mineral lubricating oil.

' 4. The processoi preparing an addition agent for mineral oil lubricants which comprises heatin: 1 mol of phenyl morpholine, 3 mols of N-dimethylaniline, and 3 mols of formaldehyde in the presence of an activated clay catalyst at a temperature of from 160to 220 F. to condense togather the three reactants, and recovering the condensation product.

5. The process of preparing an addition agen for mineral oil lubricants which comprises heating 1 mol of phenyl morphcline, 6 mols of'N- dimethylaniline and 6 mols of formaldehyde in the presence of an activated clay catalyst at a temperature of from 160 to 220 F.'to condense together the three reactants, and recovering the condensation product.

6. The process of preparing an addition agent for mineral oil-lubricants which comprises heating 1 mol of phenyl morphcline, 3 mols of N-dimethylaniline and 6 mols of formaldehyde in the presence of an activated clay catalyst at a tem perature of from 160 to 220 F. to condense together the three reactants, and recovering the condensation product.

7. A non-resinous condensation product of phenyl morpholine with from 2 to 6 mols of N- dImethylaniIine and 2 to 6 mols of formaldehyde per mol of phenyl morphcline, said product bein: obtained by the process or claim 2.

8, Anon-resinous condensation product of 1 'mol of phenyl morphcline, 3 mols of N-dimethylaniline and 3 mols of formaldehyde, said product being obtained by the process of claim 4.

9. A non-resinous condensation product of 1 mol of phenyl morpholine with 6 mols of N-dimethylaniline and 6 mols of formaldehyde, said deterioration of said 011 of a non-resinous condensation product of phenyl morpholine with from 2to 6 mols of N-dimethylaniline and 2 to 6 mols of formaldehyde per mol of phenyl morpholine, said product being obtained by the process of claim 1.

12. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount, from 0.001 to 1 per cent by weight of said oil, of a non-resinous condensation product of phenyl morphoiine with from 2 to 6 mols of N-dimethylaniline and 2 to 6 mols of formaldehyde per mol of phenyl morphcline, said product being obtained by the process of claim 1.

13. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount, suflicient to inhibit the oxidative deterioration of said oil of a non-resinous condensation product of 1 mol of phenyl morpholine, 3 mols of N-dimethylaniline and 3 mols of formaldehyde, said product being obtained by the process of claim 4.

14. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount, suflicient to inhibit the oxidative deterioration of said 011 of a non-resinous condensation product of 1 mol of phenyl morpholinefG mols of N-dimethylaniline and 6 mole of formaldehyde, said product being obtained by the process ofclaim 5.

( 15. A lubricant composition comprising a major amount of a mineral lubricating oil. and a minor amount, sufficient to inhibit theoxidative deterioration of said oil of a non-resinous condensation product of 1 mol of phenyl morphcline, 3 mols o1 N-dimethylaniline and 6 mols-of formaldehyde, said product being obtained by the process of claim 6.

HERSCHEL G. SMITH. TROY L. CANTRELL. JOHN G. PETERS.

REFERENCES CITED The following references are of record in the file 0! this patent:

"UNITED STATES PATENTS OTHER REFERENCES Tseou et 9.1., Chemical Abstracts, vol. 31 (1937). pages 1811 and 1812.

Certificate of Correction Patent No. 2,516,654 Jul 25, 1950 HERSCHEL G. SMITH ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 75, for the claim reference numeral 2 read 1 and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 10th day of October, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,515,554 Jul 25, 1950 HERSOHEL G. SMITH ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 75, for the claim reference numeral 2 read 1 and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 10th day of October, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'ssioner of Patents.

Claims (1)

1. THE PROCESS OF PREPARING AN ADDITION AGENT FOR MINERAL OIL LUBRICANTS WHICH COMPRISES HEATING PHENYL MORPHOLINE WITH FROM 2 TO 6 MOLS OF N-DIMETHYLANILINE AND 2 TO 6 MOLS OF FORMALDEHYDE PER MOL OF PHENYL MORPHOLINE IN THE PRESENCE OF AN ACTIVATED CLAY CATALYST AT A TEMPERATURE NOT IN EXCESS OF 350*F. TO CONDENSE TOGETHER THE THREE REACTANTS, AND RECOVERING THE CONDENSATION PRODUCT.