Rhodium catalysts build into the structure of a silicate support in the hydroformylation of alkenes

Rhodium is build into a nano-structured calcium silicate during the synthesis of the silicate. Thereby, it was desired to create a robust heterogeneous catalyst, which does not suffer from catalyst leaching like rhodium impregnated on a pre-formed silicate. While this was achieved, the silicate structure was adversely affected by the incorporation of rhodium — the surface area and pore volume of the material were found to be comparatively low. Alcohol and acid washing were tested to address this issue. The alcohol treatment proved detrimental as catalytic material was leached from the silicate. The acid washed rhodium containing calcium silicate was quite active in the hydroformylation of alkenes and did not suffer loss of catalyst into the product phase. Acid treated rhodium containing silicates were more active than their untreated counterparts but less selective due to access to the rhodium centers being opened.