Effect of pH on rate and selectivity behavior in biphasic hydroformylation of 1-octene

Abstract

The effect of pH on activity and selectivity of (RhCl(COD)₂/TPPTS catalyzed hydroformylation of 1-octene in a biphasic medium has been studied. The pH of the aqueous catalyst phase shows a strong influence on the rate of reaction and n/iso ratio of the aldehyde products. The effect of P/Rh ratio, catalyst and 1-octene concentration, partial pressure of hydrogen and carbon monoxide was studied at 7 and 10 pH, which showed significantly different trends. The rates increased by two- to five fold when the pH was changed from 7 to 10. While the dependence of the rate was found to be linear on the olefin and hydrogen concentration at both 7 and 10 pH, the rate of hydroformylation was found to be inhibited with increase in catalyst concentration beyond 1×10^-3 kmol m^-3. The effect of partial pressure of carbon monoxide was linear at pH 7 whereas at pH 10 a substrate inhibited kinetics was observed.