US2181914A - Oil composition containing arylated metallo-organic inhibitors - Google Patents

Description

Patented Dec. 5, 1939 UNITED STATES OIL COMPOSITION CONTAINING ARYLATED LlETALLO-ORGANIC INHIBITORS Raphael Rosen, Cranford, N. J., asslgnor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application March 19, 1935, Serial No. 11,811

14 Claims.

The present invention relates to improved oil compositions and more particularly to improved mineral lubricating oils and greases containing metallo-organic compounds.

Oils used for the lubrication of internal combustion engines and for other services involving exposure to high temperatures and air or combustion gases are subjected to severe oxidizing conditions. The use of metallo-organic com- 9 pounds for the purpose of improving lubricating oils, including increasing the resistance of such oils to oxidation and for decreasing the amount of carbon and of sludge and the development of color therein during storage and use, has been suggested in my pending applications Serial No. 719,603 filed April 7, 1934, and Serial No. 735,202 filed July 14, 1934, issued March 29, 1938 as Patent No. 2,112,305. The present application is a continuation in part of these applications.

It is an object of this invention to improve lubricating compositions and mineral oil compositions generally by the addition thereto of arylated metallo-organic compounds of improved solubility in such oils. Other and further objects of this invention will be apparent from the following description and the claims.

A metallo-organic compound is one in which a metallic element is attached directly to at least one carbon atom of a hydrocarbon radical, which radical contains hydrogen also attached to carbon but may in addition contain other elements such as nitrogen, oxygen, sulfur, chlorine, and the like; or in general may contain various non-metallic elements in addition to hydrogen and carbon.

85 The present invention relates to solubilized aryl metallo-organic compounds; that is, to metalloorganic compounds in which the metallic element is connected to a carbon atom of an aromatic hydrocarbon radical as defined above, and in which the metallic element is also connected directly with a carbon atom of an alkylated aromatic or an aliphatic hydrocarbon radical as defined above, and/or with a negative radical. Suitable negative radicals include chlorine, bromine, iodine, sulfur, polysulfide radicals, hydroxyl, SH (hydrosulfide) SCN (thiocyanate), NCS (isothiocyanate), NH2 (amine) and substituted amines, CONHz (amide), N03 (nitrate), and the m carboxylic and thiocarboxylic acid radicals. particularly fatty acid radicals such as CH3 COO (acetate), CH3 COS (thioacetate) and the like. One or more valences of the metal may also be attached to other hydrocarbon radicals which I may be similar to or different from each other,

' or such valences may be attached to hydrogen atoms or to other non-metallic atoms.

It has been found that aromatic or aryl groups are far more effective than aliphatic or alkyl groups in metallo-organic compounds for improv- 5 ing the stability of lubricating oils. However, metallo-organic compounds containing only aryl groups as the organic component are of such low solubility in hydrocarbon oils, particularly in mineral lubricating oils of high quality and visl0 cosity index, that suflicient concentrations to permit the full improving eifect of such compounds cannot be secured.

It has also been found that the solubility of such completely arylated metallo-organic com- 16 pounds can be greatly increased by substituting an alkyl group or a negative radical for one or more of the aryl groups. The resulting compounds have the desirable characteristics of high efiectiveness in improving lubricating oils and of sufli- 20 cient solubility for the preparation of optimum concentrations, and are preferred according to the present invention.

'Examples of metallo-organic compounds suitable for the present invention are: 26

In addition to increasing the solubility in oil of the arylated compounds, the substitution of negative radicals also in many instances produces metallo-organic compounds of increased eflectiveness. For example, the iodide and sulfide radicals possess this power to a marked degree;

aryl metallo-organic iodides and aryl metalloorganic sulfides being highly eflective lubricating oil sludge preventers and stabilizers.

' znegativeradicalslto he substitutedior-aryi groups ior.best',resuits depends upon the nature :ofathe number and-type of groups anti/or aryl groups. In metailo-organic compounds con- "taining relatively simple aryl groups, such as ing as many as the solubility characteristics ot the compound will permit. With complex aryl groups having a condensed ring structure, such as naphthyls, anthracyls, etc., it may be necessary to replace two or more such groups with solubilizing groups for best results.

The nature of (the solubilizing groups also varies. Alkyl groups having 10 to 18 carbon atoms in a straight chain have a greater solubilizing effect than alkyl groups of 2 to 6 or 8 carbon atoms. The alkyl groups may be either of straight or branched chain'structure, including normal, iso, secondary, tertiary and/or cyclo allwl groups, such as isopropyl groups, secondary butyl groups, tertiary amyl groups and cycle hexyl groups, also cyclo naphthenic groups, and alkylated aromatic groups such as benzyl, cresyl, propyl-phenyl, butyl-cresyl, octyl-phenyl, and the like. V

Alkylation of one or more of the aryl groups of the metallo-organic compound also increases its solubility. For example, metallo organic compounds may be used having cresyl groups, propylphenyl groups, butyl-phenyl groups, or other aryl groups containing one or more alkyl groups, of 1 to 6 or more carbon atoms, which may be normal, iso, secondary, tertiary and/or cyclo alkyl groups, attached to a carbon atom of the aryl ring.

The organic radicals, both aryl and alkyl, need not be purely hydrocarbon radicals although it is generally so preferred. For example, they may contain hydroxy and amino groups, and/or halogen or sulphur or other elements, and of particular importance are the hydroxy and amino derivatives of the aryl compounds.

While the exact nature of these various compounds and the mechanisms by which they improve the oils to which they are added, are not particularly understood, it is observed that all appear to show to a greater or lesser degree the property of decreasing the sludging tendency of the oil, which means that such decomposition products as are formed under their influence whatever their nature, are, for the most part, freely soluble or, at least, dispersable in the oil,

and that the tendency towards precipitation is thus greatly diminished. This improvement in lubricating oils is described generally as a reduction in sludge formation.

The compounds used for the present compositions are those which are soluble in hydrocarbon oils, at least to the extent necessary for the indicated purposes. If a particular eompoimd is found not to be sufficient y soluble for the best results, it has been found that the addition of more alkyl groups or of allryl groups containing a greater number of carbon atoms will increase the solubility to the point desired. It is often desirable to add small amounts of benzol or toluol or their equivalents to dissolve the compounds to be added, and to cause their intimate dispersion through the oil. If desired, the lower molecular weight solvents may be removed by distillation or otherwise, in order to obtain lubriass sts stating-compositions of desired volatility, flash, -e c.

' The amount of the metallo-organic compound used may be very small; for example, as little as 0.01 to 0.02% often produces substantially beneficial results, but it is generally desirable to use about 0.05% to 0.2% of these compounds,

and it is rare that more than 0.5% is required waxes or greases. These metallo-organic compounds may be used with such lubricating com- I positions derived from all varieties of crudes including paraflinic, naphthenic and the various mixed base crudes. The lubricating compositions used may be obtained and refined by the ordinary methods of distillation, acid treating, clay treating, alkali treating, and combinations of such treating operations, solvent extraction, bydrogenation, destructive hydrogenation, and the like, including the treatments with excess of strong or fuming sulfuric acid to produce the highly refined whi oils which are used for medicinal and technical purposes. These compounds are of particular value in motor oils, especially for crankcase lubrication, flushing oils, turbine oils, transformer oils, top cylinder lubricants, cable oils, switch oils, greases, and other lubricants used for similar purposes. The lubricants may contain more than one of the particular metallo-organic compounds mentioned herein, or all of these compounds in admixture with other metallo-organic compounds, and may also contain other substances which are customarily added to lubricating oils, such as pour point depressors, oiliness agents, dyes for cast and color, extreme pressure agents, thickeners, sludge dispersers and the like. The addition of oxidation inhibitors, such as p-naphthol and sulfurized phenol, is also of advantage as' these serve to a solubilizing group has been substituted for one of the aryl groups.

Example 1 Tetraphenyl lead, triphenyl lead iodide, tetraphenyl tin, triphenyl tin iodide and triphenyl tin chloride were each dissolved in separate portions of a petroleum lubricating oil prepared from a Gulf crude, and a petroleum lubricating oil prepared by hydrogenation of a Colombia crude.

The Gulf oil was of 15 V. I. and is a much better solvent for aromatic compounds generally than is the hydrogenated oil. The solutions were prepared by warming the oil, with stirring, until the metallo-organic compounds were completely dissolved. The solutions were then cooled to room temperature and then to 5 C. Solutions containing both 0.1% and 0.2% by weight of triphenyl lead iodide, triphenyl tin iodide and triphenyl tin ch oride showed no precipitation at either room temperature or 5 C. All solutions containing 0.2% of tetraphenyl lead and tetraphenyl tin formed precipitates at both room temperature and 5 C. Solutions containing 0.1%

of tetraphenyl lead and tetraphenyl tin formed precipitates from the hydrogenated oil at 5 C. but did not form precipitates from the Gulf oil at 5 C. or from either the hydrogenated oil or the Gulf oil at room temperature.

Erample 2 Example 3 A blank sample of a highly refined lubricating oil, S. A. E. 50, prepared by hydrogenation, was compared in a series of tests with samples of the same oil to which were added varying amounts of metallo-organic tin compounds of the types and in the concentrations shown in the following table:

Percent Cone Oxygen ab- Sligh humor 2223? test sorption test test Blank oil (Hyd. S. A. E.

0. 50 103-213-107 5 Triphenyl silicon hydride 0. 2 0. 42 'lriphenyl benzyl ger' manium 0. 2 0. 39 Phenyl tribenzyl tin..- 0.2 0. 18 Triphenyl tin sulfide" 0. 2 0. 08 3-3-3-6 40. 7 'lriphenyl n-butyl tin 2 0. 2 0. l5 5-8-7-8 'lri--naphthyl ethyl tin. 0. 2 0. l4 Triphenyl tin iodide 0. 2 0. 03 6-10-12-12 3. 4 Do 0. 05 0. 2i 21-17-l4l7 3. 3 'lriphenyl tin chloride". 0. 2 0. l4 6-6-9-6 40. 6 Triphenyl tin bromide 0. 2 0. 20 7-7-7-8 Do 0. 05 0. 27 Di henyl tin di-iodido... 0. 05 0. 29 23-2522l7 6. 9 Trflihenyl tin hydroxide. 0. 20 0. l1 Do 0. 05 0. 22 28-12-8-4 l6. 5 Triphenyl tin thiocya- 0.20 0.11 ll-l2l8-9 Triphonyl lead iodide.-.. 0. 2 0. 42 Do 0. 05 0. 42 53 58-6l56 Diphenyl arsenic chloride 0. 2 0. 24 7544-36 Emmple 4 A blank sample of a highly refined, phenol treated lubricating oil, S. A. E. 50, from a Mid-Contb nent crude was compared in a series of tests with samples of the same oil to which were added triphenyl tin iodide in varying concentrations, as

' indicated in the following table:

Concen- Cone Oxygen absorp- Sligh Inmbm tration t tion test test Blank oil 0. 40 44-35-34-26 4. 8 'lriphenyl tin iodide. 0. 2 0. l4 3 4. 1 Do 0. 05 0. 25 Do 0. 025 0. 3

either the reactions or the constituents reacting or both, may differ from those causing sludge formation. It is significant that the metallo-organic tin iodides give low figures for the Sligh test as well as for the cone test and the oxidation rate test. This has not been observed with other metallo-organic tin halides.

The cone test is conducted by passing the oil at a definite rate through a groove cut in the inner surface of a steel cone of standardized dimensions held at a temperature of 250 C. The figure reported is the deposite which is the total naphtha insoluble residue deposited on the cone and found suspended in the oil at the end of the test. The figure reported represents milligrams of insolubles per cc. of oil.

The oxygen absorption test represents the amount of oxygen in cubic centimeters absorbed during successive 15-minute intervals when oxygen is conducted in a closed circuit, bubbling through 10 cc. of the oil, which is maintained at a temperature of 200 C.

The Sligh test is conducted according to the A. S. T. M. procedure except that it is conducted for 24 hours instead of the 2-hour period recommended. See Proc. American Society for Test Materials24,964-II (1924).

From the above tables it is apparent that the solubilized aryl metallo-organic tin compounds are particularly efiective.

The present invention is not to be limited to any theoretical explanation of the action of the metallo-organic compounds, nor to any particular compounds, which are disclosed herein solely for purpose of illustration, but is to be limited by the following claims, in which it is desired to claim all novelty insofar as the prior art permits.

I claim:

1. A composition of matter comprising a hydrocarbon oil of the type boiling above kerosene, containing in solution a minor proportion of an aryl metallo-organic compound having an alkyl group attached to a metallic element thereof, said alkyl and aryl groups being connected by carbon atoms to the same atom of said metallic element.

2. A composition according to claim 1 in which said alkyl group is an aryl-alkyl group.

3. A composition according to claim 1 in which said alkyl group is a benzyl group.

4. A composition of matter comprising a hydro-carbon oil of the type boiling above kerosene containing in solution a minor proportion of a metallo-organic compound having both an aryl group and a negative inorganic radical connected to the metallic element thereof, said aryl group being connected by a carbon atom to said metallic element.

5. A composition according to claim 4 in which said inorganic radical is a sulfide.

6. A composition according to claim 4 in which said inorganic radical contains sulfur.

7. A composition according to claim 4 in which said inorganic radical is a halide.

8. A composition according to claim 4 in which said inorganic radical is an iodide.

9. A composition according to claim 4 in which said inorganic radical is selected from the group consisting of hydrides and hydroxides.

10. A composition according to claim 4 in which one valence of the metallic element of said metallo-organic compound is connected to the inorganic radical and the remaining valences are connected to aryl groups.

11. A composition according to claim 4 in which one valence oi the metallic element of said metallo-organic compound is connected to the inorganic radical and the remaining valences are 3 connected (to phenyl groupa.

12. A composition of matter comprising a hydrocarbon oil of the type boiling above kerosene containing in solution a minor proportion of a metailo-organic tin iodide compound having a carbon atom of at least one aromatic hydrocarbon radical. attached directly to the tin.

13. A composition according to claim 12 in which said metallo-organic compound is a triaryl tin iodide.

14. A composition according to claim 12 in which said metallo-organic compound is triphenyl tin iodide.

' RAPHAEL ROSEN.