Heterogeneous catalyst oxide-supported catalysts, organometallic

Catalysts speed up reactions, and provide selectivity for the desired product. Homogeneous catalysts (often organometallic compounds) act in the same phase as the reactions, heterogeneous catalysts (often transition metals on an oxide support) in another phase. 

An interesting approach to overcome these limits and thus combine the advantages of homogeneous and heterogeneous catalysis is that of supported liquid phase catalysts (SLPC or SLP). In SLPC the organometallic complex active components are dissolved in a small quantity of liquid phase dispersed in the form of an isle or film on the surface of supports. A SLPC has been applied successfully for several chemical transformations [113], particularly in the Wacker-type ethylene oxidation to acetaldehyde and vinyl acetate production by ethylene acetoxylation [114], and in other reactions catalyzed by Pd-complexes such as the Heck reaction [115]. 

Metathesis is one of the attractive methods for the conversion of alkanes and olefins, and has been developed in both homogeneous and heterogeneous catalysis fields. In homogeneous catalysis, Mo alkyl alkylidene complexes have been known to be active catalysts for metathesis [45-48]. Basset and Coperet et al. [49-53] prepared surface organometallic catalysts, which are simple monoatomic systems with hydrides, alkyl alkylidenes, or alkyl alkylidynes of Group 5 or 6 metal complexes supported on oxide surfaces for alkane and olefin metatheses. 

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