US 2244075 A
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Patented June 3, 1941 MINERAL OIL PRODUCT Louis A. Mikeska, Westfield, N. J., asslgnor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application October 12, 1938, Serial No. 234,605
The present invention relates to improved mineral oil products and more especially to oils, greases and the like which contain addition agents to improve their properties. The invention will be fully understood from the following description.
Many addition agents for lubricating oils or greases have been suggested to improve various properties, especially stability, but few have been found ,which have the marked advantage in preserving the oils under elevated temperatures, such as are encountered in internal combustion engines and in maintaining a clean engine condition. In the present instance, a new class of chemical substances has been suggested for this purpose and it has been found that these agents are very powerful in reducing carbon formation,
where R and R" represent hydrocarbon or substituted hydrocarbon groups which will be described more fully below and X represents a hydrogen atom or some other substituent group, more especially nitro groups, amino and hydroxy groups. As indicated above, the benzene ring appearing in the above mentioned formula is preferred, but other aromatic radicals may be employed such as naphthalene, anthracene and phenanthrene rings or their alkylated derivatives. The groups R and R may be hydrocarbon groups, for example alkyl groups such as methyl, ethyl, 'propyl, butyl or higher alkyl groups and the compounds containing these groups are desirable in reducing the oxidation rate of the oil. In the formula mentioned above R and R" are preferably aromatic groups such as phenyl, naphthyl, cresyl; benzyl orvarious alkylated aromatic groups. Compounds of this type are preferred to those in which R and R" are aliphatic because they are particularly desirable and effective in maintaining a clean engine condition. The said aromatic groups may be entirely of a hydrocarbon nature or they may be substituted, that is to say containing elements or radicals with atoms other than hydrogen or carbon. Thus the aromatic groups may be phenolic, containing a free hydroxyl group, or they may be sulfides or .disulfides. They may likewise contain nitro or amino groups.
The atom or radical marked X in the above said group may be in other positions as well or,
indeed, if desired no substituent is necessary. The compounds described above may be added to the oil or grease in proportions from about .10 or 1.5 or 2.0%. In this proportion they reduce the corrosive action of oils on alloy bearings such as those composed of copper, lead, cadmium, silver or the likes They likewise reduce the oxida tion very markedly and improve the carbon depositing tendency of the oil under high temperature conditions.
The reagents referred to above may be added to oils of all types whether derived from paraffinic, naphthenlc or mixed base crudes and may be used either alone or in combination with other well known agents, for example, soaps, heavy metal salts such as naphthenates, or other soluble salts of aluminum, cobalt, nickel, calcium, barium or chromium. They may be used along with dyes, pour point depressants, thickening agentsnoiliness or extreme pressure compounds.
Example I A lubricating oil of SAE No. 20.wa.s used as a blank and denoted as sample 1. To a sample of this oil was added .25% of di-n-butyl o-nitrobenzene-sulfenamide. This sample was designated sample 2. The formula of the compound added is as follows:
Oxidation rates were determined on the blank and on sample 2 by bubbling oxygen which was passed in a circulatory path including a 10 cc. sample of the 011 while held at 200 C. The
amount of oxygen absorbed was determined at intervals of -15 minutes by difference from the amount remaining uncom-bined. were as follows:
Oxidation rate Sample 1 74403528 Sample 2 15-17-16-14 Two samples 1a and 211, similar to those used above except made up with mineral oil of SAE 40 grade, were then tasted for carbon depositing tendency. In this test the oil was slowly dropped into a heated steel cone, having a circumferential groove milled cut in a screw fashion on an inside periphery so as to allow a time of contact of about one minute between the heated surface and the oil. A total volume of 60 cc. of oil is dropped from a dropping funnel during a period of 2 hours to obtain this time of contact. The temperature of the cone may be held at any desired point, but for ordinary testing 250 C. seems preferable because it best approximates The results 7 Cone dlata,
Grams Sample la .50 Sample 2a .09
It willbe understood that the larger demerit rating indicates a poorer engine "condition, and
naturally smaller amounts of carbonindicate better performance.
It will thus be seen that the addition agent has greatly improved the carbon deposit tendency of this oil.
Sample of coil containing the addition agent was found to be non-corrosive according to the ordinary copper-strip test, in spite of the addition of the sulfur in the compound added, and
when sample 2 was subjected to the known Underwood test, it was found to be much less corrosive to alloy bearings than was the blank sample 1.
Example II Using the blank oil of Example'l, a third sainple, No. 3, was madeaup containing 25% of phenyl-a-naphthyl o-nitrobenzene-sulfenamide:
The oxidation rate of this sample was determined just as in Example I, with the following results:
Oxidation rate Sample 3 10-12l313 It was likewise found to be non-cgrrosive to the copper strip test.
Example III each part of the piston'was examined, for example, the condition of the rings, the ring slits, ring grooves, as well as the total amount of carbon formed, the carbon on the under side of the piston, and the presence or absence of varnish on piston skirt. Separate ratings were given on the basis of these examinations and a composite overall demerit rating was given for the piston. In the following table, this data is summarized:
From the test data, it will be seen that the addition of 25% of the reagent has greatly improved the. performance of the oil. As a whole, the piston condition is considerably better and in each'respect it is also improved. For example,
the sticking of rings has been eliminated and the slits and grooves are both improved. The total amount of carbon is greatly diminished and the carbon on the under side of the piston is also diminshed. There is likewise less varnish on the skirt. In all, it is clear that the condition of the engine is much better with the oil to which the agent ha been added.
The present invention is not to be limited by any theory of the mechanism of-,;the engine improvement or the particular agents, which have been added, but only by thev following claims.
I claim: g
1. An improved. lubricant comprising a hydrocarbon oil and a small amount of an aromatic sulfenamide.
2. An improved lubricant comprising a hydrocarbon oil and a small amount of a compound of the formula:
where R and R" are hydrocarbon groups.
3. An improved lubricant according to claim 2 in which R and R are aliphatic hydrocarbon radicals.
4. An improved lubricant comprising a hydrocarbon oil and a small amount of a compound of a formula:
where R and R" are hydrocarbon groups and X is a substituent selected from the class consisting of -NO2, -OH and NH: groups.
5. An improved lubricant according to claim 4 in which the groups R and R" of the added compound are aliphatic.
6. An improved lubricant-"comp Demerits Piston 35 2' Ring Ring Eggs? Varnish (arbon overall Stuck mg slits grooves I piston skirt formed Gram: Reference ll SAE N0. 40 4. 81 3 810 7. 33 6. 00 4. 5 5 7. 35 Ditto +34% of inhibitor 1.59 0 ii 1.00 4.00 3 l 4 1.50
LOUIS A. MIKESKA.
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