HYDROFORMYLATION OF ALLYL ALCOHOL CATALYZED BY (RH(PPH3)3)+ MONTMORILLONITE - A KINETIC-STUDY

Rh(PPh3)3Cl 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-degrees-C and 60 atm of CO + H-2 (1:1) gave GAMMA-hydroxybutyraldehyde (96%) and 2-methyl-3-hydroxypropionaldehyde (4%). The kinetics of hydroformylation of allyl alcohol catalysed by 1 was studied in the concentrations range of catalyst 0.1 to 0.75 mM, allyl alcohol 0.025 to 0.25 M, CO + H-2 (1:1) pressure 5 to 30 atm and temperature between 70 to 90-degrees-C. The rates of hydroformylation of allyl alcohol catalysed by 1 showed a first order dependence with respect to catalyst, allyl alcohol (up to 0.1 M), CO and H-2 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 allyl alcohol.