US3356472A - Gasoline composition containing phenyltrimethyllead - Google Patents

Description

United States Patent C 3,356,472 GASOLINE COMPOSITION CONTAINING PHENYLTRIMETHYLLEAD Wallace L. Richardson, Lafayette, Maurice R. Barusch, Richmond, and George J. Kautsky, El Cerrito, Calif., assignors to Chevron Research Company, a corporation of Delaware No Drawing. Continuation of application Ser. No. 397,323, Sept. 17, 1964, which is a continuation of application Ser. No. 31,565, May 25, 1960. This application June 9, 1966, Ser. No. 556,526

1 Claim. (Cl. 4469) ABSTRACT OF THE DISCLOSURE Hydrocarbon base fuel having a clear Research octane number of at least 90 and from 20 to 60% by volume of aromatic hydrocarbons contains from about 0.5 to about 4 ml. of phenyltrimethyllead per gallon.

This application is a continuation of Wallace L. Richardson, Maurice R. Barusch and George J. Kautsky, US. application Serial No. 397,323, filed Sept. 17, 1964, now abandoned, which in turn is a continuation of Wallace L. Richardson, Maurice R. Bamsch and George J. Kautsky US. application Serial No. 31,565, filed May 25, 1960, now abandoned.

This invention relates to an improved gasoline composition. More particularly, the invention i concerned with a superior new hydrocarbon fuel of the gasoline boiling range containing phenyltrimethyl lead.

Gasoline compositions of high octane number are commonly required for modern spark ignition internal combustion automobile and aircraft engines. Engines of these types in general use today are designed with high compression ratios for more efiicient operation. Since the present trend is toward engines of still higher compression ratios for increased power and improved performance, there is a constant demand for gasoline compositions of even higher octane number.

Improved methods of refining and blending gasoline base stocks, and additives such as lead tetraethyl, have been employed to meet the demands for higher octane number gasoline compositions. However, it has been generally realized that there is at present a limit to the improvement in octane number that can be obtained by such conventional methods and additives. New gasoline base stocks with the combinationof different additives are greatly needed, therefore, to avoid present limitations and provide gasoline compositions of high octane number for future use in automobile. and aircraft engines.

It has now been found that a uperior new gasoline composition of high octane number is provided by a hydrocarbon base fuel boiling in the gasoline boiling range to which is added phenyltr'imethyl lead in amounts sufficient to improve the octane number, preferably at least 0.5 ml. per gallon of base fuel. Y

The improved gasoline compositions of the invention show unexpectedly high octane numbers compared to previously known combinations of hydrocarbon base fuels and additives. Hydrocarbon base fuels, together with the specified phenyltrimethyl lead compound and mixtures thereof in accordance with the invention, have octane numbers which are substantially higher than similar base fuels employing the conventional lead tetraethyl additive in the same lead content. This is surprising since it has been generally accepted heretofore that other lead compounds are distinctly less efficient than lead tetraethyl with respect to octane number improvement.

The hydrocarbon base fuel of the composition, according to the invention, is prepared by conventional refining and blending processes. It normally contains straightchain paraflins, branched-chain paraflins, olefins, aromatics and naphthenes. Since straight-chain parafiins have a tendency to adversely affect octane number, the content of such hydrocarbons is ordinarily low.

As already mentioned, the base fuel is a hydrocarbon fuel boiling in the gasoline boiling range. Generally described, such fuel have an ASTM (D-86) distillation with an initial boiling point of about 100 F. and a final boiling point of about 425 F. Preferably, the unleaded base fuel has a Research octane number of at least 85 as determined by the accepted CFR engine test method. Also, the base fuel preferably contains at least 20% by volume of aromatic hydrocarbons. Less than 30% by volume of olefinic hydrocarbons are present in the fuel. The total parafiin and naphthene hydrocarbon content of the preferred fuel may be as much as 80% by volume. For best overall engine performance, fuels containing in the range of 20 to 60% by volume of paraffinic and naphthenic hydrocarbons are preferred for volatility and other desirable gasoline characteristics. The m-ore preferred hydrocarbon base fuels are those which contain from 20 to 60% by volume aromatic hydrocarbons and from 0 to 30% by volume of olefinic hydrocarbons. Most preferably, a gasoline having all-around desirable characteristics ethyl, carbonyl derivatives of iron and cyclopentadienyl derivatives of metals such as manganese or iron. Other gasoline additives, such as scavengers like ethylene chloride or bromide, oxidation inhibitors, corrosion inhibitors,

surface ignition suppressants like phosphorus compounds,

detergents, and the like may be present.

The following examples illustrate the preparation of phenyltrirnethyl lead compound in accordance with this invention. Unless otherwise specified the proportions are on a weight basis.

Example 1 One mole of phenylmagnesiumbromide Grignard reagent in approximately 400 ml. of anhydrous ethyl ether is prepared. To this is added 1 mole of trimethyl lead chloride. The mixture is heated and stirred at reflux for one hour. After standing at room temperature overnight, an aqueous solution of ammonium chloride is slowly added with stirring. The ether is removed by distillation, giving -a relatively nonvolatile residue. This residue is redissolved in ether and washed with an aqueous solution of potassium hydroxide followed by a water wash. The solution is then washed in dilute hydrochloric acid solution and then once more with distilled water. The ether solution is then dried over anhydrous sodium sulfate and the ether removed by distillation. The residue is fractionally distilled at reduced pressure. The principal fraction, boiling at to C. at 5 mm. Hg pressure, is collected. The majority of the material boils at 84 C. The yield is 28 grams.

Example 2 Lithium (15 g.) in the form of ribbon is cut into small pieces and placed under anhydrous diethyl ether ml.) in a 3-necked flask equipped with stirrer, dropping funnel and reflux condenser. Bromobenzene (15.7 g.) is dissolved in its own volume of anhydrous ether and is placed in the dropping funnel. 40 drops of the bromobenzene solution is added to start the reaction which is then maintained by adding the remaining bromobenzene at such a rate as to achieve general reflux. After all the material has been added, the mixture is refluxed by heat- 4 is compared with 3.00 ml./ gal. lead tetraethyl. The Improvement is the difference in the octane number obtained with phenyltrimethyl lead less the octane number obtained with the equivalent amount of lead tetraethyl.

TABLE Hydrocarbon Composition Motor Octane Research Ex. No. Paraflins Octane Phenyltrimethyl Tetracthyl Lead Improveand Olefins, Aromatics, Unleaded Lead w; Naphthenes, Percent by Percent by Percent by Volume Volume Volume Ml. Gm N M1. Gm. No.

3 47 33 94- 1 2- 9 5. 07 89. 7 3. O 4. 94 88. 3 1 4 4 54 Trace 46 98. 1 2. 9 5.07 96. 3 3. 0 4. 94 95. 2 1,1

ing for one-half hour. The phenyl lithium product in solution is filtered through glass wool into a clean 3-necked fiask equipped with stirrer, dropping funnel and reflux condenser. Trimethyl lead chloride (28.8 g.) is added cautiously to avoid too violent reaction. The reaction mixture is then poured onto a mixture of ice and aqueous ammonium chloride solution. The ether layer is separated and dried with anhydrous magnesium sulfate. Ether is removed by distillation and the residue fractionally distilled at reduced pressure. The yield is 14.6 g., amounting to 45% of theory based on the trimethyl lead chloride used. The product has a boiling point of 56 C. at 1 mm. Hg pressure. The refractive index 11 1.5803.

In still other similar preparations the yield is somewhat improved to at least 60% of theoretical.

In further illustration of the superior new gasoline composition of the invention, several compositions and tests thereon are given in the following additional examples. These tests show the improved effect of the combination of the hydrocarbon base fuel with phenyltrimethyl lead as compared with fuels containing other lead compounds.

The following table is a summary of the pertinent data of the examples. The type of compositions of the hydrocarbon base fuel is shown with respect to the percent by volume of the paraffins and naphthenes, olefins and aromatics. The clear octane number of the base fuel is also given. This octane number, as already mentioned, is the accepted Research octane number which is usually employed in designating a given gasoline. This method is described as Research Method D-908 in ASTM Manual of Engine Test Methods for Rating Fuels."

The table shows the effect on octane number by the addition of phenyltrimethyl lead as compared to lead tetraethyl. The octane number in this comparison is based on the Motor Method D-357 of the ASTM Manual of Engine Test Methods for Rating Fuels. This method, which is more stringent than the Research Method, illustrates more accurately the desirable qualities of the improved gasoline composition of the invention.

In the table, the effect of phenyltrimethyl lead compared with lead tetraethyl, etc., is based on gasoline compositions containing an equal lead concentration. That is to say, that about 2.9 ml./ gal. of phenyltrimethyl lead The examples summarized in the above table show that the improved gasoline composition of the invention containing phenyltrimethyl lead is decidedly better on the basis of octane number rating than comparable gasoline compositions of the type known heretofore containing tetraethyl lead. Surprisingly, other phenyl lead compounds give decidedly worse octane numbers than tetraethyl lead. For instance, diphenyldimethyl lead in the base fuel of Example No. 3 gave an octane rating of 87.7 which is 0.6 octane lower than the 88.3 with tetraethyl lead.

We claim:

A hydrocarbon base fuel, boiling in the gasoline boiling range, adapted for use in spark ignition internal combustion engines, having a clear Research octane number of at least 90, said fuel being characterized in that the hydrocarbon composition contains from 20 to 60% by volume of aromatic hydrocarbons, not more than 30% by volume of olefinic hydrocarbons and not more than 60% by volume of paraffinic and naphthenic hydrocarbons, said fuel containing from about 0.5 to about 4 ml. of phenyltrimethyllead per gallon, said fuel having a Motor Method octane number greater than the corresponding octane number of a mixture of said hydrocar bon composition containing a molar equivalent of tetraethyllead.

References Cited UNITED STATES PATENTS 1,592,954 7/1926 Midgley 44--69 1,949,949 3/1934 Alleman 4469 2,310,376 2/1943 Smyers et al. 4469 2,862,801 12/1958 De Witt 4469 OTHER REFERENCES Calingaert, The Organic Compounds of Lead, Chemical Review, vol. 2, 1925-6, pp. 45, 46, 64 and 78 relied on, complete article pp. 43-83, published for the P.C.S. by Williams Wilkinson Co.

Wagner et al., Improved Motor Fuels Through Selective Blending, paper presented before 2d meeting of the American Petroleum Institute, November 1941, p. 1019.

DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner,