Supported rhodium and supported aqueous-phase catalyst, and supported rhodium catalyst modified with water-soluble TPPTS ligands Original Research Article

Two types of novel catalysts: supported rhodium and supported aqueous-phase (SAP/Rh-SiO2), and supported rhodium modified with water-soluble TPPTS ligands (TPPTS-Rh/SiO2), were prepared. Hydroformylation of 1-hexene showed that SAP/Rh-SiO2 and TPPTS-Rh/SiO2 catalyst processed high activity for aldehydes and especially high selectivity towards aldehydes and high n/i- ratio of aldehydes. These results were significantly different from the performances of Rh/SiO2 catalyst, but very comparable to those of SAP catalyst. 31P NMR spectrum of TPPTS-Rh/SiO2 catalyst demonstrated that TPPTS ligands chemically bonded to highly dispersed rhodium metal particles. It make clear the reason that yield of aldehydes of SAP/Rh-SiO2 was nearly the sum of the yield of SAP catalyst and the yield of TPPTS-Rh/SiO2 catalyst, while all of catalytic selectivities were equal, because SAP/Rh-SiO2 was actually made up of SAP and TPPTS-Rh/SiO2 catalysts. The catalytic performance of TPPTS-Rh/SiO2 catalyst strongly depended on the molar ratio of P:Rh, which was similar to that of SAP catalyst to a certain extent.