(666c) Kinetics of Pd Catalyzed Carbonylation of Olefins and Alcohols: Comparison of Homogeneous and Heterogeneous Catalysts

Carbonylation of olefins and alcohols using homogeneous catalysts has gained considerable interest due to their important applications in synthesis of a variety of commercially important products [1,2], especially the non-steroidal anti-inflammatory drugs consisting of 2-arylpropionic acids (e.g. Ibuprofen, Naproxen) [3] It is well known from previous work that Pd complexes with different ligands, co-catalysts and promoters are highly active under mild operating conditions but with variable regioselectivity [4]. For example, the carbonylation of styrene and substituted styrene derivatives using Pd catalysts show high activity as well as regio-selectivity in the synthesis of aryl propionic acids. The role of metal halide promoters in regioselectivity has however not been well understood. In this presentation, the experimental results on the kinetics of carbonylation of aryl olefins and alcohols using homogeneous and heterogenized Pd complex catalysts will be reported. Particularly, the effect of substrate, catalyst, ligand, promoter and water concentrations, CO pressure, and temperature on the rate of carbonylation as well as concentration-time profiles using Pd(OAc)2(PPh3)2 and PdCl2(PPh3)3 catalysts as precursors with LiCl and TsOH as promoters will be discussed. The differences in the rate behavior with aryl olefins and alcohols as substrates will also be discussed. Rate equations based on reaction mechanisms will be presented. This lecture will also discuss the preliminary kinetic study using the heterogeneous Pd complex catalysts prepared by tethering and anchoring techniques and compare the performances of the homogeneous and heterogenized Pd catalysts.

References

[1] Falbe, J. (Ed) New Synthesis with Carbon Monoxide, Springer-Verlag, Berlin, 1980

[2] Sarkar, B. R.; Chaudhari, R. V. Catalysis Survey from Asia. 2005, 9, 193

[3] (a) Rieu, J. P.; Boucherle, A.; Cousse, H.; Mouzin, G. Tetrahedron,1986, 42, 4095. (b) Applied Homogeneous Catalysis with Organometallic Compounds; Cornils, B., Herrmann, W. A., Eds.; VCH: Weinheim, Germany, 1996; Vol. 1. (c) Colquhoun, H. M.; Thompson, D. J.; Twigg, M. V. Carbonylation: Direct Synthesis of Carbonyl Compounds; Plenum Press: New York, 1991; Chapter 6.

[4] (a) Seayad, A; Jayasree, S.; Chaudhari, R. V., Catalysis Letters. 1999,61,99; (b) Jayasree, S; Seayad, A.; Chaudhari, R. V. Org. Lett. 2000, 2 (2) 203; (c) Mokhopadhyay, K.; Sarkar, B.R.; Chaudhari R. V. J. Am. Chem. Soc. 2002,124,9692