Solid-supported surface catalysis, metal

Solid-Supported Surface Catalysis by Metal Complexes. Hong et al. (1987a, b, in press) have prepared a variety of hybrid catalysts between Co(II) phthalocyanine complexes and the surfaces of silica gel, polystyrene-divinylben-zene, and Ti02 and tested these hybrids for catalytic activity with respect to the autoxidation of hydrogen sulfide, sulfur dioxide, 2-mercaptoethanol, cysteine, and hydrazine ... 

In contrast to supported homogeneous catalysis, surface organometallic chemistry (SOMC) uses an inorganic oxide (ExOy) as a solid ligand, on which the metal is directly attached by at least a bond with a surface atom, usually an oxygen, through a M-OE bond. 

These reactions are unlike any we have encountered so far. They are heterogeneous reactions, which means that the reacting system consists of two or more phases. Usually, the metal catalyst is present as a finely divided solid suspension in the liquid or solution to be reduced. Alternatively, the metal is deposited on an inert solid support such as carbon, barium sulfate, alumina (A1203), or calcium carbonate. Then the mixture of the liquid substrate and solid catalyst is shaken or stirred in a hydrogen atmosphere. However, the actual reaction takes place at the surface of the metal catalyst and is an example of heterogeneous or surface catalysis. 

The early heterogeneous catalysis study was simply based on metal powders, while highly dispersed catalyti-cally active components with high-surface solid supports has quickly become the main stream. Compared to homogeneous system, heterogeneous catalysis possesses a number of beneficial features. One of the primary aims of... 

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