Hydroformylation of ally1 alcohol catalysed by (Rh(PPh3)3)+/montmorillonite: a kinetic study

Abstract

Rh(PPh,),Cl complex exchanged with modified montmorillonite clay at room temperature gave a (Rh(PPh3)3)+ species, 1, anchored in the hydration layers of the clay. Hydroformylation of allyl alcohol catalysed by 1 at 70°C and 60 atm of CO + H2 (1:1) gave gamma-hydroxybutyraldehyde (96%)and 2-methyl-3-hydroxypropionaldehyde (4%). The kinetics of hydroformylation of ally1 alcohol catalysed by 1 was studied in the concentrations range of catalyst 0.1 to 0.75 mM, ally1 alcohol 0.025 to 0.25 M, CO + H2 ( 1:l) pressure 5 to 30 atm and temperature between 70 to 90°C. The rates of hydroformylation of ally1 alcohol catalysed by 1 showed a first order dependence with respect to catalyst, ally1 alcohol (up to 0.1 M) , CO and H2 concentrations respectively. Substrate inhibition effect was observed when the substrate/catalyst mole ratio exceeds 440. The insoluble catalyst residue formed during substrate inhibition runs showed an IR stretching at 630 cm-3 which was attributed to the formation of Rh(II)-allylic complex. Repeated use of the separated catalyst for 60 h showed no loss in catalytic activity in hydroformylation of ally1 alcohol.