US3258476A - Method of making trivinylaluminum - Google Patents

Description

United States Patent Oflice METHOD OF MAKING TRIVINYLALUMINUM Donald J. Foster, South Charleston, and Erich Tobler,

Charleston, W. Va., assignors to Union Carbide Corporation, a corporation of New York No Drawing. Filed Aug. 10, 1959, Ser. No. 832,450 6 Claims. (Cl. 260-448) This invention relates to a new composition of matter, trivinylaluminum and to a method of making it. It also relates to trivinylboron, trivinylgallium, trivinylindium and trivinylthallium.

Our new compound, trivinylaluminum is represented by the formula (CH CH) Al. It is a viscous oil at C. but cannot be kept unsolvated at room temperature. In the pure state it is unstable above a temperature of about 0 to C. It is soluble in aliphatic and aromatic hydrocarbons and forms stable etherates.

In our process trivinylaluminum is made by reacting metallic aluminum with the vinyl derivative of an element more electronegative than aluminum, as represented by the equation:

3 (CH CH),.M+xAl x(CH =CH) Al+3M wherein M is a metal more electronegative than aluminum and x is the valence of the metal. The new compositions of matter trivinylgallium, trivinylindium and trivinylthallium can be made by the process of our invention as can also trivinylboron. Depending on the compound desired, boron, gallium, indium or thallium is reacted with a more electronegative metal such as divinylmercury to yield the divinyl compound of the particular Group IIIA element.

In a preferred embodiment of our process divinylmercury is reacted with metallic aluminum foil. The divinylmercury is dissolved in an aliphatic hydrocarbon such as pentane under an inert atmosphere such as nitrogen and the aluminum foil is added to the solution at any temperature from below 0 C. to as high as the boiling point of the aliphatic solvent. The aluminum begins to dissolve almost immediately and soon disappears while a pool of molten mercury forms. The supernatant liquid containing the aliphatic hydrocarbon solvent and trivinylaluminum is separated from the mercury and the solvent is then removed under reduced pressure to yield the desired trivinylaluminum product.

Divinylmercury is a preferred reagent. Also useful, however, are vinyl compounds of metals more electronegative than aluminum. Divinylmercury may be made by adding mercuric chloride to vinylsodium in a solvent such as butyl ether.

While the use of a solvent is not essential to the process, it is preferred to employ an aliphatic hydrocarbon solvent in which the trivinylaluminum is soluble and stable for some time at room temperature or above. Any solvent may be employed which is substantially inert to the reactants and the products and in which they are both soluble, for example aromatic hydrocarbons. We have found, however, that in general amines, alcohols, ethers and carbonyl-containing compounds tend to either react with the product or form such strongly bonded complexes with it that isolation of the pure product is impaired. Suitable solvents include pentane, hexane, heptane, benzene, toluene, xylene and the like.

If no solvent is employed the reaction temperature must be kept below about 0 C. to 10 C. because of the instability of unsolvated trivinylaluminum above these temperatures. While the use of an aliphatic hydrocarbon solvent permits reaction temperatures of 100 C. or above, it is preferred to maintain the reaction temperature at 25 C. or below due to the tendency of trivinylaluminum to decompose with time at elevated temperatures. Temperatures below about 30 C. are avoided because of a re- 3,258,476 Patented June 28, 1966 duction in the reaction rate with a decrease in temperature. An inert atmosphere such as dry nitrogen is employed to minimize decomposition of the product. The rare gases and hydrocarbon gases may also be used as they do not react with trivinylalumium.

In the process of the invention the stoichiometric quan tities of reagents are preferred, but the ratios of reactants are not narrowly critical and can be widely varied without affecting the outcome of the reaction. While aluminum foil is a preferred form of aluminum for the reaction it can be any form small enough for reaction, as in a powder, slivers, granules, turnings, etc.

We obtained proof of the composition as trivinylaluminum in several ways. Elemental analysis agreed with the calculated value for trivinylaluminum. The product was reacted with acetone and subsequently hydrolyzed to give dimethylvinylcarbinol, a known compound. In this reaction the mercury was removed prior to the addition of acetone and, in addition, under similar conditions, divinylmercury does not react with acetone. As a final test trivinylaluminum was reacted with water to give ethylene and aluminum hydroxide.

Trivinylaluminum is useful as an intermediate for organic synthesis as are trivinylgallium, trivinylindium and trivinylthallium. Trivinylaluminum is highly pyrophoric and hence is useful for this property. For example it can be added in small quantities to fuels for jet engines to prevent so-called flame-outs. Also it can be mixed with hydrocarbon rocket fuels in concentrations up to 30 percent in order to improve burning and reduce screech.

Example I To 15.3 grams (0.06 mol) of divinylmercury dissolved in 200 milliliters of dry pentane was added 1.1 grams (0.04 gram atom) of aluminum foil. The entire reaction was conducted in an atmosphere of high purity nitrogen. The reaction temperature was maintained at about 20 C. and almost immediately there was evidence for solution of the aluminum and deposition of mercury. Within minutes all of the aluminum had disappeared and a pool of liquid mercury could be removed from the reaction flask. A total of 83 percent by weight of the theoretical amount of mercury was recovered. The temperature of the product solution was then lowered to 20 C. while the pentane was removed by reducing the pressure. The product was a viscous oil with a faint yellow coloration and consisted of trivinylaluminum. An elemental analysis of the compound was made with the following result:

Calculated for C H Al: C, 66.6; H, 8.39; Al, 24.95. Found: C, 65.8; H, 8.4; Al 25.7.

Upon warming to a temperature of 0 C. to 10 C. the trivinylaluminum decomposed to a yellow-brown solid with a sponge-like consistency.

Example II To 15.3 grams (0.06 mol) of divinylmercury dissolved in 200 milliliters of dry pentane was added 1.1 grams (0.04 gram atom) of aluminum foil. The reaction was conducted in an atmosphere of high purity nitrogen at a temperature of about 20 C. After about 75 minutes the reaction was complete and to the product mixture there was added a solution of 7.0 grams (0.12 mol) of acetone in 10 milliliters of pentane. The ensuing reaction was exothermic and after it had subsided water was added to hydrolyze the product. The organic layer was then separated and dried over anhydrous sodium sulfate, after which it was distilled. A material boiling at a temperature of 98-9 C. was isolated and proved to be identical, both chemically and spectrographically, with a sample of dimethylvinylcarbinol prepared by the reaction of vinylmagnesium bromide with acetone.

3 Example III Trivinylaluminum was prepared in the manner of Example I and the product was hydrolyzed with water. The evolved gas was collected and analyzed by means of a mass spectrometer. The gaseous material was almost exclusively ethylene with only trace amounts of hydrogen and concentrates. The yield of trivinylaluminum calculated from the evolved ethylene was over 80 percent of the theoretical.

Example IV A butyl ether slurry containing 135 grams (0.5 mol) of mercuric chloride was added portion-wise to a butyl ether suspension containing 50 grams (1.0 mol) of vinylsodium maintained at a temperature of about minus C. After the addition was complete, the reaction mixture was stirred for an additional thirty minutes before it was allowed to come to room temperature. Water was added to hydrolyze unreacted starting material and dissolved the inorganic salts. The organic layer was dried over magnesium sulfate and distilled at a reduced pressure of millimeters of mercury. After removal of the solvent, the product boiled at a temperature of 59 C. to 61 C. at 20 millimeters. This product was divinylmercury.

What is claimed is:

1. Process for making trivinylaluminum which comprises reacting aluminum with (CHFCH) M wherein M is a metal more electronegative than aluminum and x is the valence number of the metal, said process being conducted at a temperature of from 30 C. to 10 C.

2. Process as claimed in claim 1 wherein M is mercury and x is 2.

3. Process for making trivinylaluminum which comprises reacting aluminum with (CH =CH) M wherein M is a metal more electronegative than aluminum and x is the valence number of the metal, said process being conducted at a temperature of from 30 C. to C. in an aliphatic hydrocarbon solvent.

4. Process as claimed in claim 3 wherein M is mercury and x is 2.

5. The process for preparing trivinylaluminum which comprises reacting metallic aluminum with divinylmercury at about 20 C. until the reaction is substantially complete.

6. The process for preparing trivinylaluminum which comprises reacting metallic aluminum with divinyl mercury under conditions conducive to the formation of trivinylaluminum, and recovering trivinylaluminum from the product of said reaction.

References Cited by the Examiner UNITED STATES PATENTS 2,921,954 1/1960 Ramsden 260429.7 3,010,985 11/1961 Ramsden 260448 OTHER REFERENCES Beilsteins Handbuch der Organischen Chemie, 4th Edition, 2nd Addition to vol. IV (1942), page 1024.

European Scientific Notesvol. 6, No. 13 (July 1, 1952), page 178 (pub. by Office of Naval Research, London).

Grosse et al., Die Chemie der metall-organischen Verbindung (1937), page 12.

TOBIAS E. LEVOW, Primary Examiner.

ABRAHAM H. WINKELSTEIN, Examiner.

Claims (1)

1. 6. THE PROCESS FOR PREPARING TRIVINYLALUMINUM WHICH COMPRISES REACTING METALLIC ALUMINUM WITH DIVINYL MERCURY UNDER CONDITIONS CONDUCTIVE TO THE FORMATION OF TRIVINYLALUMINUM, AND RECOVERING TRIVINYLALUMINUM FROM THE PRODUCT OF SAID REACTION.