US3072571A - Calcium base greases containing chlorinated bicycloheptene compounds - Google Patents

Description

United States Patnt Ofiice 3,072,571 CALCIUM BASE GREASES CONTAINING CHLO- RINATED BICYCLOHEPTENE COMPOUNDS Terence B. Jordan, Fishkill, and Howard A. Kirsch,

Poughkeepsie, N.Y., assignors to Texaco Inc., a corporation of Delaware No Drawing. Filed June 13, 1958, Set. No.741,744

8 Claims. (Cl. 252-40.?)

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

In accordance with thisinvention, 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, chlorine, hydrocarbon groups and substituted hydrocarbon groups, -OR", -COR", and -COOR groups, wherein R is a hydrocarbon group or substituted hydrocarbon group. The hydrocarbon groups represented by R, R and R" may be aliphatic or aromatic groups or may comprise both aliphatic and aromatic groups, such as alkyl, aryl, alltaryl and aralkyl groups. They may contain various substituents of the types commonly present in lubricant additives, preferably neutral or substantially neutral groups, such as, for example, Cl, Br, I, OH, SH, amino groups, etc. Preferred compounds for example, include those wherein R and R are COOR" groups and wherein R" is a lower aliphatic hydrocarbon group, containing from 1 to about 10 carbon atoms.

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 esterifying 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 obtain- Patented Jan. 8, 1963 able having an OK. load in the Timken 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.

While all of the chlorinated bicycloheptene compounds of the class described above are effective extreme pressure agents in calcium base greases, it is not intended to imply that they are equivalents in their extreme pressure or other effects in these greases. The most generally suitable compounds of this class are those wherein R and R are -COOR" groups and wherein R is a lower aliphatic hydrocarbon group. However, compounds of this class wherein R and R are hydrogen or hydrocarbon groups are preferred in some cases because of their superior compatibility with other additives employed in the grease compositions and for various other reasons. Also, a greater improvement in the extreme pressure properties may be obtained by employing more highly chlorinated compounds, wherein at least .R or R is a chlorinated hydrocarbon group, and such compounds wherein R or R is a chlorinated aliphatic hydrocarbon group may be preferred for use in compositions where a high degree of heat stability is not required.

The greases of this invention comprise oleaginous liquids thickened to a grease consistency with a calcium fatty acid soap and containing a small amount, sufficient 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 obtained 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 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 compounnds are the aliphatic dicarboxylic acid diesters, such as, di-Z-ethylhexyl sebacate, di(secondary amyl) sebacate, di-2-ethylhexylazelate, di-isooctyl adipate, etc. Suitable mineral oils are those having viscosities in the range from about 100 seconds Saybolt Universal at 100 F. to about 225 seconds Saybolt Universal at 210 F., and may be either naphthenic c-r 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 preformed soap and additive with the lubricating oil or by saponification in situ in a portion of the oieaginous liquid employed in the grease. Where a calcium salt is employed in the grease, the preformed salt may be added to the mixture following the saponification, or the saponiiication may be carried out upon a mixture of the higher and lower fatty acids.

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

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

The di-Z-ethylhexyl chlorendate is obtained as described hereinabove, employnig 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 3523 56 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 35:65 ratio by weight of a refined naphthenic distillate oil having a Saybolt Universay viscosity at 100 F. of about 100 seconds, and a residual motor oil stock from a naphthene base crude having a Saybolt 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 190-210 F. and held at a temperature within that range for four hours to complete the saponification. The mixture is then heated further to 300340 F. and held at a temperature in that range for one hour to drive oh the water and to condition the soap. The heat is then shut 01f 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 is below 200 F., 4,222 grams of di-2-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 effective 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 lead naphthenate and sulfurized sperm oil.

The heat stability test of the above table is carried outby 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 caused the grease to break down to a fluid in the heat stability test and also lowered the dropping point to 387 F.

EXAMPLE II Table II E.P. Additive None 12% Pb-S 10% Diadditive methyl chlorendato Water Absorption Test:

Water absorbed, percent 50 250+ Pena. of emulsion, AS'IM 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 comparable 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.

5 EXAMPLE In Another grease representative of the greases of this invention is prepared as described in Example I except that 10 percent of l,2,3,4,7,7-hexachloro-5-phenylbicyclo- [2.2.1]-2-heptene is employed as the extreme pressure additive. This compound is prepared by reacting together hexachlorocyclopentadiene and styrene as described in Example 4 of U.S. 2,606,910. A slightly stringy grease is obtained having an ASTM penetration at 77 F. of 395 unworked and 325, worked 60 strokes, a dropping point of 472 F. and an O.K. load of 40 in the Timken test.

EXAMPLE IV Another grease representative of the greases of this invention has the following composition in percent by weight:

The chloromet-hylhexachlorobicycloheptene is more completely identified by the name l,2,3,4,7,7-hexachloro- 5-chloromethyl-bicyclo-[2.2.1]-2-heptene. It is obtained by heating together hexachlorocyclopentadiene and allyl chloride in equimolar proportions at 300 F. for four hours in a sealed reactor.

The grease preparation is suitably carried out as described in Example 11 of U.S. 2,822,331, employing a cold premix step as described therein and a maximum processing temperature of about 280 F. The saponifiable material may be the commercial 12-hydroxystearic acid material sold under the trade name of Hydrofol Acids 200. Typical tests upon this material include a saponification number of 182, a neutralization number of 178, a hydroxyl number of 155 and a titer, C. of 73.9. The mineral lubricating oil employed in the saponification mixture may be a refined naphthenic distillate oil having a Saybolt Universal viscosity at 100 F. of about 140 second, and a residual stock of the character described in Example I may be blended in following the dehydration so as to give a 45:55 blend of the distillate and residual oils respectively in the finished grease.

A smooth buttery grease is obtained as described above, having an ASTM penetration at 77 F. of 365, unworked, 328 worked 60 strokes, a dropping point 279 F. and an OK. load in the Timken test of 45.

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

We claim:

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, suflicient to impart improved extreme pressure properties to the composition, of a chlorinated bicycloheptene compound represented by the formula 1| 01- -o1 01-43 O-R H at wherein R and R are chosen from the group consisting of hydrogen, hydrocarbon groups and chlorinated hydrocarbon groups.

2. A lubricating grease according to claim 1 wherein the said chlorinated bicycloheptene compound is phenylhexachlorobicycloheptene.

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

4. A lubricating grease according to claim 1 containing min-or proportion of a calcium salt of a lower fatty acid. a

5. 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.

6. A lubricating grease according to claim 1 wherein the said calcium fatty acid soap is a hydroxy fatty acid soap.

7. A lubricating grease according to claim 1 wherein the said soap is calcium 12-hydroxystearate.

8. A lubricating grease consisting essentially of a mineral lubricating oil containing about 12-20 percent by weight of a calcium fatty acid soap, about 3-6 percent by weight of calcium acetate and about 5-15 percent by weight of phenylhexachlorobicycloheptene.

References Cited in the file of this patent UNITED STATES PATENTS Herzfeld et :al. Aug. -12, 1952 Morway Feb. 21, 1956 Dorinson Nov. 20, 1956 Dilworth et a1. Feb. 4, 1958 OTHER REFERENCES

Claims (2)

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

4. A LUBRICATING GREASE ACCORDING TO CLAIM 1 CONTAINING MINOR PROPORTION OF A CALCIUM SALT OF A LOWER FATTY ACID.