US2691001A

US2691001A - Mineral lubricating oil composition

Info

Publication number: US2691001A
Application number: US300492A
Authority: US
Inventors: Elmer B Cyphers; David W Young
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1952-07-23
Filing date: 1952-07-23
Publication date: 1954-10-05
Anticipated expiration: 1971-10-05

Description

P atenteci Oct. 5, 1954 UETED STAT ear orric-E MINERAL LUBRICATING OIL COMPOSITION No'DraWing. Application July 23, 1952,

Serial 010.300,!92

2 Claims.

Thepresent invention relates to the use of 4,4 isopropylidine bis (2isopropylphenol) as an additive for mineral lubricating oil compositions.

Various bis phenols have been suggested as additives for organic compositions subject to oxidation. The use of such phenols containing a his linkage in the para position with respect to the hydroxyl radicals has met with little success. For example, diphenylol propane is relatively ineffective as a lubricant antioxidant. Furthermore, this compound cannot be used in the usual mineral lubricant compositions because it is substantially completely insoluble in such materials at ordinary temperatures.

In accordance with the present invention it has been found that mineral lubricating oil compositions containing dissolved therein small amounts of 4,4 isopropylidine bis (2-isopropylphenol) are excellent compositionsfor use in lubricating in- More- This compound is readily and inexpensively prepared by condensing ortho isopropylphenol with propionaldehyde or dimethyl ketone, usually in the presence of a condensation catalyst. The general method of preparation of such compounds is well known to the art and does not form a part of the present invention.

The 41,4 isopropylidine bis (2-isopropylphenol) is dissolved in mineral lubricating oils in amounts in the range of about 0.05 to 1.5 or 2% by weight, the upper limit being restricted to some extent by the type of mineral oil base stock being used. A preferred concentration is in the range of about 0.1 to 1.0% by weight.

The lubricating oil base stocks used in the compositions of this invention may be straight mineral lubricating oils or distillates derived from paraninic, naphthenic, asphaltic or mixed base crudes. The lubricating base stocks will generally range from about 40 to 150 seconds (Say- 2 bolt) viscosity at 210 F. The viscosity'index may range from about 0 to 100 or higher, al-

though for aviation lubricants, which are the preferred base stocks in the practice of the present invention, the higher viscosity indexes are preferred. The bisphenol of the present invention is quite suitable, however, for automotive lubricants, diesel lubricants and the like. In addition to "the above mentioned materials, the compositions may contain other agents including pour point depressants, viscosity index improvers,

by reference to the following examples.

- oiliness agents and the like.

Example '1 .Solubility studies The bis phenol compound oi-the presentinvention, lfl' isopropylidine bis (2-isopropylphenol) wasiound to be readily soluble in mineral lubricating oils to the extent of as much as 1.0 to

1.5 weight percent at room temperature.

Diphenylol propane, on the other hand, was insoluble in mineral lubricants at room temperature. A solution was obtained when 0.25 weight percent diphenylol propane was agitated in a mineral lubricant ata temperature of 250 F., but, on cooling to room temperature, this bisphenol substantially completely crystallized out of solution.

Example 2.-Staeger oxidation studies Two highly solvent-extracted Mid-Continent lubricant base stocks were used in these studies. Base stock I had an S. S. U. viscosity at 210 F. oi 85. Base stock II had an S. S. U. viscosity at 210 of 43 and a viscosity index of 112. Blends of each of these oils containing 0.25 weight percent of various bisphenols as well as the oils per se were tested.

The test employed was a modification of the Staeger test and consisted essentially of storing a 200 ml. sample of oil in a rotating shelf oven maintained at 100 C. -1. A 40 x 70 mm. freshly polished copper strip was placed in the 400 ml. container to serve as an oxidation catalyst. The strip was removed every 72 hours and replaced by a clean strip. The shelf moved at an angular velocity of 4-6 B. P. M., and positive ventilation of 1.5 to 2.0 cubic feet of air per hour was maintained. Oil samples were withdrawn periodically from the container and the neutralization num- Staeger" Oxidation Life, Hours Additive Tested Base Base Stock I Stock II None 75 95 Diphenylol propane 75 85 4,4-ispropylidene-di-o-cresol 84 220 4,4-isopropylidine bis (2-isopropylpheno1) 154 440 2,2 bis (2-hydroxy-3-tert.-butyl-5-methoxyphenyl) propane 100 285 The compound of the present invention is about two to four times as effective as the corresponding bisphenols containing either no alkyl substituents or methyl substituents, It is also markedly superior to a meta bisphenol containing methoxy substituents.

Example 3.Aluminum cup coking studies Oil blends were prepared containing various concentrations of several bisphenols in a solventextracted Mid-Continent aviation base oil having a viscosity at 210 F. of about 100 Saybolt seconds. These blends and a sample of the base oil per se were evaluated by the aluminum cup coking test. This test determines the eifectiveness of an additive for inhibiting coking of lubricants under the severe temperature conditions normally encountered in aviation engines.

The test was conducted by placing the oil in an aluminum measuring cup of known weight and stirring the oil while applying heat. The side walls of the cup were maintained at a temperature of 500 F. while heating the oil at the bottom 4 until it reached 550 F. The stirring was then stopped for 10 minutes followed by stirring for 10 minutes. At the end of the fourth alternate stirring and non-stirring period, the oil was discarded, and the cup was weighed. The results are shown in the following table:

The compound of the present invention is considerably more effective than a related compound having a his configuration ortho to the hydroxyl groups and alkyl substituent groups in both ortho and para positions.

What is claimed is:

1. A mineral lubricating oil composition containing a major proportion of a mineral lubricat ing oil and dissolved therein a minor oxidation inhibiting amount of 4,4'-isopropylidine bis (2- isopropylphenol) 2. A composition as in claim 1 wherein the amount of said bis phenol is in the range of about 0.05 to 1.5% by weight, based on the total composition.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,017,827 Bannister Oct. 5, 1935 2,295,985 Baird Sept. 17, 1942 2,482,748 Dietzler Sept. 27, 1949 2,515,906 Stevens July 18, 1950 2,591,651 Young Apr. 1, 1952 2,636,002 Capell Apr. 21, 1953 2,651,572 Bichon" Sept. 8, 1953

Claims

1. A MINERAL LUBRICATING OIL COMPOSITION CONTAINING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL AND DISSOLVED THEREIN A MINOR OXIDATION INHIBITING AMOUNT 4,4''-ISOPROPYLIDINE BIS (2ISOPROPYLPHENOL).