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Basic Molecular Sieve Catalysts//Side-Chain Alkylation Of Toluene By Methanol

1985; Elsevier BV; Linguagem: Inglês

10.1016/s0167-2991(09)60157-9

2542-6613

Juan M. Garcés, G.E. Vrieland, S.I. Bates, Felix Scheidt,

Catalysis and Oxidation Reactions

The use of zeolites as acidic catalysts has received widespread attention because their introduction in important industrial processes. The base catalyzed alkylation of alkylaromatics with olefins results in selective addition of the olefin to the side chain. Similarly, basic catalysts lead to the side chain alkylation of toluene with methanol. This reaction takes place over alkali metal exchanged zeolites, basic oxides, and basic salts either pure or supported on carbon. In zeolite X, the larger alkali metal cations lead to more active catalysts, and boron and phosphorous additives provide more active and selective catalysts for the direct synthesis of styrene. Lithium exchanged zeolites produce only xylenes, typical of acidic catalysts. Infrared (IR) studies of various cation forms of zeolite X used in methanol decomposition showed formation of methoxide, formate, and carbonate species on catalysts treated with methanol at 673°K. This chapter presents chemical observations, equilibrium thermodynamic data, and mass spectroscopy to support an equilibrium model which involves metal oxides, metal carbonates, zero valent metals, and CO2.