US3158575A - Calcium base greases containing chlorinated bicycloheptene compounds - Google Patents

Description

United States Patent C) 3,158,575 CALCIUM BASE GREASES CfiNTAINiNG CHEER!- NATED BICYfiLGl-EEPTENE COMPOUNDS Terence .iordan, Fishldli, and Howard A. Kirsch, Poughheepsie, N.Y., assignors to Texaco Inca, New York, N.Y., a corporation of Delaware No Drawing. Original application June 13, 1958, Ser. No. 741,744, new Patent No. 3,672,571, dated Jan. 8, 1963. Divided and this application .iune 21, 1962, Ser. No. 294,073

8 Claims. (Ci. 252--4i.7)

This invention relates to improved lubricating greases, and more particularly to calcium base greases containing chlorinated bicycloheptene compounds.

In accordance with this invention, compounds represented by the following structural formula are employed as extreme pressure additives in calcium base greases:

wherein R and R are selected from the group consisting of hydrogen and COOR" groups, wherein R" is a lower aliphatic hydrocarbon group, containing from 1 to about carbon atoms, at least one substituent represented .by R and R being a -COOR" group. The preferred compounds are those wherein both R and R are COOR" groups.

The above compounds are obtainable by reacting hexachlorocyclopentadiene with a suitable unsaturated hydrocarbon compound in the Diels-Alder Diene Synthesis, as described by S. H. Herzfeld et al. in US. 2,606,910. The compounds represented by the formula wherein R and R are COOR groups are readily obtained by reacting hexachlorocyclopentadiene with maleic anhydride as described in Example 12 of that patent, hydrolyzing the product to give hexachloroendomethylenetetrahydrophthalic acid, commonly known as chlorendic acid, and then esterfying the latter with a suitable alcohol under conventional esterification conditions.

We have found that the compounds of the above class are particularly advantageous extreme pressure additives for calcium base greases. They impart extreme pressure properties to such greases which are equal or even superior to the most effective extreme pressure additives which have been employed heretofore for this purpose, differently from their effect in other greases wherein they have little or no effectiveness in improving extreme pressure properties. In addition, they are substantially free from undesirable effects such as are found with other extreme pressure additives of various types in calcium base greases, including the softening effect which is generally found with other halogenated compounds having high extreme pressure effectiveness, and the deterioration in water resistance properties resulting from the use of extreme pressure additives of various types such as sulfurized fatty oils. By the use of the chlorinated bicycloheptene compounds, calcium base greases for heavy duty services, such as steel mill greases, are readily obtainable having an OK. load in the Timkin Test of at least about 40 pounds, which is ordinarily specified for such greases, combined with the other properties required, including a high dropping point, good heat stability and good water resistance properties.

The greases of this invention comprise oleaginous liquids thickened to a grease consistency with a calcium fatty acid soap and containing a small amount, sufiicient to impart improved extreme pressure properties to the composition, of a chlorinated bicycloheptene compound of the class described above. Ordinarily, the grease will contain from about 5 to about 35 percent of the calcium fatty acid soap, although smaller amounts, down to about 3 percent may be employed to obtain very soft greases and higher amounts, up to about 45 percent, may be employed to obtain block type greases. The composition may suitably contain from about 1 to about 20 percent by weight of the chlorinated bicycloheptene compound.

The calcium soaps employed in these greases are soaps of higher fatty acids, particularly those containing from about 12 to 32 carbon atoms per molecule, as well as hydroxy substituted acids of this type. The soaps are ob tained by saponification of such fatty acids or their glycerides or other esters. The preferred saponifiable materials are fatty acids and hydroxy fatty acids containing from about 14 to about 24 carbon atoms per molecule, and the glycerides or other esters of such acids.

In accordance with a preferred embodiment of this invention, the grease composition comprises a minor proportion of the calcium salt of a lower fatty acid such as formic, acetic or propionic acid, in addition to a calcium fatty acid soap as described above. Such salts may be present as the calcium formate, acetate, propionate, etc., or they may be present in the form of a complex with the calcium soap as described, for example, in US. 2,735,815. The composition may contain the calcium lower fatty acid salt in an amount from about 0.5 to about 20 percent by weight. Preferably, the weight ratio of calcium soap to calcium salt is in about the range 5:1 to 1:3. A particularly suitable grease for steel mill applications comprises about 12-20 percent by weight of calcium higher fatty acid soap and about 3-6 percent by Weight of calcium lower fatty acid salt.

The oleaginous liquids employed in the greases of this invention may be any suitable oils of lubricating characteristics, including the conventional mineral oils, synthetic lubricating oils prepared by cracking and polymerizing products of the Fischer-Tropsch process and the like, as well as other synthetic oleaginous compounds such as polyesters, polyethers, etc., within the lubricating oil viscosity range. Such synthetic oleaginous compounds including mixtures thereof, may be substituted in whole or in part for the conventional mineral lubricating oils. Examples of these compounds are the aliphatic dicarboxylic acid diesters, such as, di-Z-ethylhexyl sebacate, di (secondary amyl) sebacate, di-Z-ethylhexylazelate, di isooctyl adipate, etc. Suitable mineral oils are those having viscosities in the range from about seconds Saybolt Universal at 100 F. to about 225 seconds Saybolt Universal at 210 F., and may be either naphthenic or parafiinic oils or blends of the two.

The grease preparation may be carried out by any suitable means, such as by merely mixing together the pre formed soap and additive with the lubricating oil or by saponification in situ in a portion of the oleaginous liquid employed in the grease. Where a calcium salt is employed in the grease, thepreformed salt may be added to the mixture following the saponification, or the saponification may be carried out upon a mixture of the higher and lower fatty acids.

The following examples are given for the purpose of more fully disclosing the invention.

Example I A grease representative of the preferred embodiment of this invention has the following composition in'percent by weight:

Calcium tallowa-te 13.2 Calcium acetate 4.7 Di-Z-ethylhexyl chlorendate 10.0 Glycerine 1.2 Excess lime 0.2 Mineral lubricating oil Remainder The di-2-ethylhexyl chlorendate is obtained as described herinabove, employing Z-ethylhexanol for the esterification. Typical tests upon this material include a molecular weight of 613, a chlorine content of 34.7 percent and a boiling point at 0.15 mm. of mercury of 352- 356 F.

A detailed method for the grease preparation is as follows: A steam heated laboratory grease kettle is charged with 5,450 grams of Star Tallow, 1,362 grams of acetic acid, 1,674 grams of calcium hydroxide, and 7,260 grams of mineral lubricating oil, which is a blend in a :65 ratio by weight of a refined naphthenic distillate oil having a Saybolt Universal viscosity at 100 F. of about 100 seconds, and a residual motor oil stock from a naphthene base crude having a Sayboit Universal viscosity at 210 F. of about 205 seconds. Typical tests upon the Star tallow include a saponification number of 199, a neutralization number of 21.5, an iodine number of 51 and a titer C. of 39 and a hydroxyl number of 21. The mixture is heated with stirring to 190210 F. and held at a temperature within that range for four hours to complete the saponification. The mixture is then heated further to 300 340 F. and held at a temperature in that range for one hour to drive off the water and to condition the soap. The heat is then shut off and the grease mixture allowed to cool to about 200 F. while 23,154 grams of the lubricating oil are added gradually with stirring. When the temperature of the mixture below 200 F, 4,222 grams of di-Z-ethylhexyl chlorendate are added. The grease is finally drawn below 190 F.

A dark slightly stringy grease is obtained by the method described above having an ASTM penetration at 77 F. of 396 unworked, and of 318 worked 60 strokes.

The following table shows the extreme pressure and other properties of a grease obtained as described above, containing the chlorinated dicycloheptene compound, in comparison with those of two other greases, obtained by employing two different extreme pressure additives in the same base grease, which are among the most efiective extreme pressure additives employed heretofore in calcium base greases. One of these additives was a chlorinated hydrocarbon containing about 66 percent by weight of chlorine and sold under the trade name of Strobane, and the other was a commercial mixture of ead naphthenate and sulfurized sperm oil.

The Heat Stability Test of the above table is carried out by stirring the grease at a rate of 18.5 revolutions per minute while it is maintained at 350 F. for 3 periods of 5 hours each. Standard ASTM penetrations are taken at the end of each period.

As shown by the table, the diethylhexyl chlorendate was fully equivalent to the other two additives in imparting extreme pressure properties to the calcium base grease, but it did not soften the grease as did the other two additives, particularly the other chlorinated compound, which causal the grease to break down to a fluid in the Heat Stability Test and also lowered the dropping point to 387 F.

Example I! TABLE I1 4 12% Pb-S 10% Dr- E. P. Additive None additive. methyl chlorendate Water Absorption Test:

Water absorbed, percent 50 250+ 45 Pene. of emulsion, ASTM .i 255 400+ 243 The Water Absorption Test of the above table is that described in Army and Navy Specification AN-G-3a (Amendment of March, 1943). In this test small increments of water (5 percent) are worked into a 20 gram sample of the grease until no further increments can be worked in within five minutes. The water absorption of the grease is expressed in terms of the percentage of water incorporated, based on weight (20 grams) of grease.

As shown by the table, the water resistance of the product containing the chlorendic acid diester was com parable to that of the base grease, which is considered excellent. On the other hand, the lead-sulfur additive caused a. very high water absorption and excessive softening of the grease as shown by the data.

This application is a division of our application Serial No. 741,744, filed June 13, 1958, now U.S. 3,072,571,

wherein calcium soap thickened greases containing chlorinated bicycloheptene compounds of the formula wherein R and R are selected from the group consisting of hydrogen, chlorine, hydrocarbon groups and substituted hydrocarbon groups, OR" and COR" groups are disclosed and claimed.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and there fore only such limitations should be imposed as are indicated in the appended claims.

We claim: 7

1. A lubricating grease consisting essentially of an oleaginous liquid as the chief component thickened to a grease consistency with a calcium fatty acid soap and containing'a minor amount, sufficient to impart improved extremepressure properties to the composition,

of a chlorinated bicycloheptene compound represented by the formula wherein R and R are selected from the group consisting of hydrogen and COOR" groups, wherein R" is an aliphatic hydrocarbon group containing 1-10 carbon atoms, at least one substituent represented by R and R eing a COOR" group.

2. A lubricating grease according to claim 1 wherein the said oleaginous liquid is a mineral oil.

3. A lubricating grease according to claim 1 containing a minor proportion of a calcium salt of a lower fatty acid.

4. A lubricating grease according to claim 1 containing calcium acetate in a proportion of about 1:5 to about 3: 1 by weight with the said calcium soap.

5. A lubricating grease according to claim 1 wherein both R and R of the formula are COOR groups.

6. A lubricating grease according to claim 1 wherein the said chlorinated bicycloheptene compound is dimethyl chlorendaite.

7. A lubricating grease according to claim 1 wherein the said chlorinated bicycloheptene compound is di-2- ethylhexyl chlorendate.

8. A lubricating grease according to claim 1 wherein R" is an alkyl group.

References Qited in the file of this patent UNITED STATES PATENTS 2,735,815 Morway Feb. 21, 1956 2,771,423 Dorinson Nov. 20, 1956 2,822,331 Dilworth et a1. Feb. 4, 1958 2,846,392 Morway et a1 Aug. 5, 1958 2,967,826 Dilworth et a1. Jan. 10, 1961 2,971,913 David et a1. Feb. 14, 1961 OTHER REFERENCES HET Acid, by Hooker Electrochemical Co., Bulletin No. 40, New York, 1952, 13 pages.

Claims (1)

1. A LUBRICATING GREASE CONSISTING ESSENTIALLY OF AN OLEAGINOUS LIQUID AS THE CHIEF COMPONENT THICKENED TO A GREASE CONSISTENCY WITH A CALCIUM FATTY ACID SOAP AND CONTAINING A MINOR AMOUNT, SUFFICIENT TO IMPART IMPROVED EXTREME PRESSURE PROPERTIES TO THE COMPOSITION, OF A CHLORINATED BICYCLOHEPTENE COMPOUND REPRESENTED BY THE FORMULA.