Applications in the Synthesis of Organic Chemicals

In the field of organic chemistry, the main applications using bimetallic catalysts prepared by surface redox reactions were for selective hydrogenation and hydrogenolysis reactions. 

The selective hydrogenation of organic molecules with different unsaturated functional groups is an important challenge in synthesis processes for the production of valuable chemical compounds. 

By FTIR of adsorbed CO, a preferential deposit of Cu on Pd sites of lower coordination was observed on the bimetallic catalysts prepared by the redox reaction. 

On the contrary, in the co-impregnated systems, a Cu distribution occurred on the dense Pd(lll) planes. It was reported that the formation of carvotanacetone is produced mainly on the Pd sites of high coordination where the desorption of the molecule is favored. The adsorption is stronger on low coordination sites, leading to a higher residence time of the molecule and then to further hydrogenation [82]. 

The performances of bimetallic Rh-Ge/Si02 and Rh-Ge/Al203 catalysts prepared by catalytic reduction were measured for another a,p-unsaturated aldehyde, namely citral (Fig. 9.7). The addition of Ge to Rh by the surface redox reaction promoted the hydrogenation of citral to the unsaturated alcohols (geraniol/nerol), while the saturated aldehyde (dtroneUal) was the main product on the monometallic Rh catalyst [41]. 

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