OXO process: Applications, catalytic activity and recycling

The heterogeneous hydroformylation reaction represents an attractive industrial route for the production of aldehydes due to the relatively easy separation of products and high turnover of the rhodium catalysts. To study the recycling process and the characterization of the supported catalyst, a catalyst was prepared by impregnating 5% of HRhCO(PPh₃)₃ alone or with 10% of heteropolyacid (HPA). Rh15MCM-E, RH15W10MCM-E, and Rh15Mo10MCM-E, which were prepared by refluxing 5% (PPh₃)₃ in MCM-41 functionalized by HPA-W₁₂ and HPA-Mo₁₂ in ethanol, were evaluated for their activity and selectivity in hydroformylation of styrene. Hydroformylation of styrene proceeded in the presence of the catalytic amount of Rh15Mo10MCM-E affording a good yield and selectivity for the branched and linear aldehydes, even in the absence of free PPh₃ or any other ligand often used in homogeneous or immobilized systems. The study of the recycling and the leaching of the supported catalysts were achieved with 1-octene in a similar manner to the hydroformylation of styrene. The hydroformylation of 1-octene was conducted with 50 mg of Rh15W10MCM-E using cyclohexane as a solvent. The products were nonaldehyde, 2-methyl octanaldehyde, 2-ethyl heptanaldehyde, and 2-propyl hexanaldehyde. This is an abstract of a paper presented at the 14th Saudi-Japan Joint Symposium (Dhahran, Saudi Arabia 12/5-6/2004).