Aluminum economical synthesis

Organoaluminum Compounds. Apphcation of aluminum compounds in organic chemistry came of age in the 1950s when the direct synthesis of trialkylalurninum compounds, particularly triethylalurninum and triisobutylalurninum from metallic aluminum, hydrogen, and the olefins ethylene and isobutylene, made available economic organoalurninum raw materials for a wide variety of chemical reactions (see a-BONDED alkyls and aryls). 

In 1950 the Fischer-Tropsch synthesis was banned in Germany by the allied forces. Sinarol, a high paraffinic kerosene fraction sold by Shell, was used as a substitute. This ban coincided with the rapid development of the European petrochemical industry, and in due time Fischer-Tropsch synthesis applied to the production of paraffins became uneconomic anyway. After the war there was a steady worldwide increase in the demand for surfactants. In order to continually meet the demand for synthetic detergents, the industry was compelled to find a substitute for /z-paraffin. This was achieved by the oligomerization of the propene part of raffinate gases with phosphoric acid catalyst at 200°C and about 20 bars pressure to produce tetrapropene. Tetrapropene was inexpensive, comprising a defined C cut and an olefinic double bond. Instead of the Lewis acid, aluminum chloride, hydrofluoric acid could now be used as a considerably milder, more economical, and easier-to-handle alkylation catalyst [4],... 

Sodium aluminum hydride can he prepared from NaH. but direct synthesis from the elements is more economical. 

Of the techniques mentioned above, direct synthesis seems the most promising. It is a convenient and economical technique for the industrial production of trialkyl derivatives of aluminum, because the raw stock is not so scarce. Besides, the reaction releases small amounts of by-products. 

Zeolites are microporous crystalline aluminosilicates built from corner-connected TO4 (T = Si or Al) tetrahedra. Their micropores with uniform dimensions give rise to molecular sieve properties. Tetracoordinated aluminum atoms lead to ion-exchange properties and make internal acid sites possible. They are economically important as detergent builders, as adsorbents, and, because zeolites have high thermal stability, as catalysts in the petrochemical industry. They are also considered to have a high potential as catalysts in the synthesis of fine chemicals. 

Indole synthesis starting from 2-unsubsituted anilines represents an atom-economical synthetic route that utilizes more readily available substrates. The Yamamoto group developed a method for nucleophilic introduction of alkynyl groups at the ortho position of the aniline moieties of A-phenylhydroxyamine derivatives 214 using aluminum acetylides 215 (Scheme 19.56) [101]. They applied this chemistry successfully to indole synthesis using Castro s conditions (Cul in DMF) to obtain indoles 217. 

---