Beryllium alkyls/aryls

Ziegler-Natta Catalysts (Heterogeneous). These systems consist of a combination of a transition metal compound from groups IV to VIII and an organometallic compound of a group I—III metal.23 The transition metal compound is called the catalyst and the organometallic compound the cocatalyst. Typically the catalyst is a halide or oxyhalide of titanium, chromium, vanadium, zirconium, or molybdenum. The cocatalyst is often an alkyl, aryl, or halide of aluminum, lithium, zinc, tin, cadmium, magnesium, or beryllium.24 One of the most important catalyst systems is the titanium trihalides or tetra-halides combined with a trialkylaluminum compound. 

The actual isolation of beryllium dialkyls in a pure state has only just been accomplished by Gilman and Schulze, and their work throws doubt upon the accurac of that of previous investigators. Their method of procedure is the one suggested by Krause and Wendt. In 1926, Durand claimed to have prepared beryllium methyl iodide, but the work has since been disproved by Gilman and Schulze. These workers have isolated beryllium alkyl halides by heating beryllium, alkyl halides, and ether in the presence of catalysts, such as mercuric chloride, beryllium chloride, or free bromine. The first aryl compound, beryllium phenyl iodide, has been prepared by a similar process. 

Most commonly, the catalyst component consists of halides or oxyhalides of titanium, vanadium, chromium, molybdenum, or zirconium, and the cocatalyst component often consists of an alkyl, aryl, or hydride of metals such as aluminum, lithium, zinc, tin, cadmium, beryllium, and magnesium. The catalyst systems may be heterogeneous (some titanium-based systems) or soluble (most vanadium-containing species). Perhaps the best known systems are those derived from TiCl4 or TiCls and an aluminum trialkyl. 

Beryllium alkyls and aryls are best made by reaction types 18.10 and 18.11 respectively. They are hydrolysed by water and inflame in air. 

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