Hydroesterification of cyclohexene using the complex Pd(PPh3)2(TsO)2 as catalyst precursor: Effect of a hydrogen source (TsOH,H2O) on the TOF and a kinetic study (TsOH: p-toluenesulfonic acid) |
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| Institution: | 1. Université d''Artois, Unité de Catalyse et de Chimie du Solide (UCCS), UMR 8181, Faculté des Sciences Jean Perrin, Rue Jean Souvraz, SP 18, F-62307 Lens Cedex, France;2. Université de Lille, Unité de Catalyse et de Chimie du Solide (UCCS), UMR 8181, ENSCL, Bât C7, 59650 Villeneuve D''Ascq, France;3. Roquette Frères, 1 rue de la Haute Loge, F-62136 Lestrem, France;1. Bioorganic Laboratory, Department of Chemistry, Institute of Integrated & Honors Studies (IIHS), Kurukshetra University, Kurukshetra, Haryana 136119, India;2. Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150, Australia;3. Perron Institute for Neurological and Translational Science, Perth 6005, Australia;4. Centre of Biotechnology of Sfax, University of Sfax, Route de Sidi Mansour km 6, 3018 Sfax, Tunisia;5. Institut Supérieur de Biotechnologie de Sfax, Université de Sfax, Route de Sokra km 4, 3000 Sfax, Tunisia |
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| Abstract: | The hydroesterification of cyclohexene is catalyzed by a preformed Pd(PPh3)2(TsO)2 complex I in methanol as solvent. The effect of PPh3, TsOH, and water on the TOF has been evaluated. The system I/PPh3/TsOH=1/6/8, in the presence of 800 ppm of H2O, at 373 K and under 2.0 MPa of CO leads to a TOF as high as 850 h?1. The increase of TOF observed adding a hydride source such as TsOH and H2O suggests that Pd-hydride species plays a key role in the first step of the catalytic cycle. The initial reaction rate increases linearly with the concentration of cyclohexene and of MeOH and passes through a maximum with increasing the pressure of CO. The rate equation r0=k1PCO (1+k2PCO+k3PCO2)?1 fits well the experimental data. The values of k1, k2, and k3 have been evaluated at different temperatures. From the plot ln k versus 1/T, E1=19.4 kcal/mol, E2=20.6 kcal/mol and E3=6.5 kcal/mol have been evaluated. On the basis of experimental evidences and of the kinetic study, a catalytic cycle mechanism has been proposed. |
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