Gallium reactions with alkenes

Further catalytic uses of zeolites and related materials include polymerisation of alkenes as well as the development of basic zeolitic materials generated by the incorporation of alkali metal ions. Gallium- and boron-substituted zeolites have already been shown to be useful catalysts in wide variety of reactions (Table 2.2) and undoubtably these will be followed by novel zeotypes including mesopor-ous materials with other catalytically active elements within their frameworks.40... 

Hydrogen fluoride (HF) is often used as a catalyst for alkenes, since there is less tar (fewer decomposition and polymeric by-products) and the volatile catalyst is easily removed. Both ferric chloride (FeCl3) and BF3 are common catalysts for alkene-aromatic coupling. Typical alkyne catalysts are aluminum chloride, gallium trichloride (GaCl3), BF3, and sulfuric acid. Reaction of a mixture of xylenes with a trace amount of BF3 in liquid HF gave the thermodynamic mixture 18% ortho, 60% meta, and 22% para but treatment with excess BF3 gave virtually 100% m-xylene. 07b,117... 

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