Studies on the Synthesis of Sulfur-Containing Polymer-Rhodium Complexes and Their Use as Catalysts for Hydroformylation

A kind of nonphosphine polymer catalyst has been synthesized by partial substitution of the chlorine atoms of poly(vinyl chloride) with -SR groups (n-propyl, n-hexyl, benzyl, and p-tolyl). Rhodium complexes of these sulfur-containing polymer ligands are highly active catalysts for the hydroformylation of α-olefins. At 60°C and 60 kg/cm2, conversion of 1-hexene was nearly complete within 4–6 h. The rhodium to 1-hexene mole ratio was 1/800 to 1/1 000, and the catalyst could be reused once again without losing activity. The effects of reaction temperature, pressure, H2/CO ratio, S/Rh ratio, concentration of catalyst, and reaction time on the catalyst's activity were examined. The possible mechanism of hydroformylation is discussed. A copolymer of butyl vinyl sulfide and acrylonitrile was synthesized and its rhodium complex was prepared. The catalytic acitvities of this complex for the hydroformylation of 1-hexene was also investigated.