Aluminum discovery

Fermi planned to stop off in London for an international physics conference on his way home from South America. His young colleagues sent him word of their aluminum discovery. He reported to the conference on the neutron work. (Szilard also attended, happy to hear praise for his summer experiments and well launched toward a paying fellowship at Oxford.) Fermi said his group had studied sixty elements so far and had induced radioactivity in forty of them. Discussing the radiative-capture problem he cited the Cavendish results and those of Amaldi and Segrd on aluminium, which were both, he said, to be considered particularly important. Segrd describes the tempestuous aftermath ... 

Heterogeneous Catalysis. The main discovery of the 1980s was the use of titanium sihcaUte (TS-1) a synthetic zeoHte from the ZSM family containing no aluminum and where some titanium atoms replace siUcon atoms in the crystalline system (Ti/Si = 5%) (33). This zeoHte can be obtained by the hydrolysis of a siUcate and an alkyl titanate in the presence of quaternary ammonium hydroxide followed by heating to 170°C. Mainly studies have been devoted to the stmcture of TS-1 and its behavior toward H2O2 (34). The oxidation properties of the couple H2O2/TS-I have been extensively developed in... 

PoIysuIfonyIa.tlon, The polysulfonylation route to aromatic sulfone polymers was developed independendy by Minnesota Mining and Manufacturing (3M) and by Imperial Chemical Industries (ICI) at about the same time (81). In the polymerisation step, sulfone links are formed by reaction of an aromatic sulfonyl chloride with a second aromatic ring. The reaction is similar to the Friedel-Crafts acylation reaction. The key to development of sulfonylation as a polymerisation process was the discovery that, unlike the acylation reaction which requires equimolar amounts of aluminum chloride or other strong Lewis acids, sulfonylation can be accompHshed with only catalytic amounts of certain haUdes, eg, FeCl, SbCl, and InCl. The reaction is a typical electrophilic substitution by an arylsulfonium cation (eq. 13). 

The discovery by Ziegler that ethylene and propylene can be polymerized with transition-metal salts reduced with trialkyl aluminum gave impetus to investigations of the polymerization of conjugated dienes (7—9). In 1955, synthetic polyisoprene (90—97% tij -l,4) was prepared using two new catalysts. A transition-metal catalyst was developed at B. E. Goodrich (10) and an alkaU metal catalyst was developed at the Ekestone Tke Rubber Co. (11). Both catalysts were used to prepare tij -l,4-polyisoprene on a commercial scale (9—19). 

The discovery that Lewis acids can promote Diels-Alder reactions has become a powerful tool in synthetic organic chemistry. Yates and Eaton [4] first reported the remarkable acceleration of the reactions of anthracene with maleic anhydride, 1,4-benzoquinone and dimethyl fumarate catalyzed by aluminum chloride. The presence of the Lewis-acid catalyst allows the cycloadditions to be carried out under mild conditions, reactions with low reactive dienes and dienophiles are made possible, and the stereoselectivity, regioselectivity and site selectivity of the cycloaddition reaction can be modified [5]. Consequently, increasing attention has been given to these catalysts in order to develop new regio- and stereoselective synthetic routes based on the Diels-Alder reaction. 

Twenty-five years after its discovery, aluminum was a precious metal. Then a French chemist developed procedures for reducing aluminum compounds using sodium metal. The price of the metal dropped 100-fold. Even so, in 1885 aluminum was a semiprecious metal used for esoteric purposes such as a prince s baby rattle and the cap for the Washington Monument. 

Hall capitalized on his discovery by founding a company for the manufacture of aluminum. That company became immensely successfial, eventually growing into Alcoa. It made the Halls very rich. 

The flexibility of the synthesis method provides for opportunities to incorporate other elements besides silicon. One of the first elements added was Al (11). Soon after the discovery of the silicon based TUD-1, it was found that adding suitable aluminum sources to the above procedure yielded very similar Al-Si-TUD-1 stractures. Since then, many other TUD-1 variants have been prepared. Most TUD-1 variants are either Si-TUD-1 or an M-Si version, where M is another element (e.g.,... 

Osborn s discovery (14) that aluminum halides bimTto oxo ligands in tungsten oxo neopentyl complexes, and that these complexes decompose to give systems which will efficiently metathesize olefins, raised more questions concerning the role of the Lewis acid. A subsequent communication (20) answered some of the questions the aluminum halide removes We oxo ligand and replaces it with two halides to yield neopentylidene complexes (equation 8). 

Transition metal catalysis plays a key role in the polyolefin industry. The discovery by Ziegler and Natta of the coordination polymerization of ethylene, propylene, and other non-polar a-olefins using titanium-based catalysts, revolutionized the industry. These catalysts, along with titanium- and zirconium-based metallocene systems and aluminum cocatalysts, are still the workhorse in the manufacture of commodity polyolefin materials such as polyethylene and polypropylene [3-6],... 

The discovery of diradicals in sulfuric acid or Lewis acid solutions of bianthrone and thianthrene raises the possibility of acid-catalyzed radical reactions for any unsaturated compound.448 Anything that increases the equilibrium concentration of the diradical should promote radical reactions. These results are important because previous to their discovery few chemists would have hesitated to say that a reaction catalyzed by sulfuric acid or aluminum trichloride, for example, was an entirely ionic one. Now we would not want to venture such an opinion without other reasons. 

In the early 1950s there was the quite contemporary discovery—in three different laboratories—of processes for the polymerization of ethene at low pressure using solid catalysts The catalyst used by the Standard Oil of Indiana was Mo(VI) oxide supported on aluminum oxide the one by Phyllips Petroleum was Cr(VI) oxide still supported on silica/alumina the catalyst studied by Ziegler and his co-workers at the Max Planck Institute at Miihlheim... 

The discovery of the new class of high-silica zeolites "pentasil" during the last decade has attracted considerable interest due to the important applications of these zeolites in catalysis. The best known member of this family of zeolites is ZSM-5, developed in the Mobil laboratories. The unusual properties of pentasil zeolites have rekindled the interest in other high-silica zeolites, prepared by dea-lumination of low-silica zeolites. In this paper we shall review the preparation methods of aluminum-deficient zeolites, and shall discuss the properties of these materials, with emphasis on recent advances in their characterization. 

The recent discovery that acetylated glycopyranosyl bromides may be reduced in high yields with lithium aluminum hydride to the corresponding 1,5-anhydroglycitols661 represents an improvement over the reductive desulfurization process and will doubtless make this class of compound even more readily available in the future. 

Since the discovery by Ziegler and Natta that transition metal complexes, in the presence of aluminum alkyl compounds, can efficiently catalyze the polymerization of ethylene and propylene, significant efforts have been devoted to the development of new catalytic systems for polymerization of olefins. One of the... 

The chemical laboratory at the Ecole Normale offered little excitement in the way of theory in the last decades of the nineteenth century. Under Deville, three fundamental themes in inorganic chemistry had been pursued the preparation of aluminum the exploration of metals in the platinum series and the discovery of equilibrium in gaseous milieus, including the study of the dissociation of elementary vapors at high temperatures.27 Neither Deville nor his pupils were interested in general theories. As noted in chapter 3, Lespieau later commented,... 

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