Hydroesterification of ethylene to methyl propionate has been studied using the catalyst precursor Pd(PPh3)2(TsO)2, which is active in presence of PPh3 and TsOH (TOF = 5700 h−1 at 120◦C, 40 atm (CO/C2H4 = 1/1), Pd/PPh3/TsOH = 1/8/10, [Pd] = 2 × 10−3 mol l−1, solvent methanol, H2O = 800 ppm). In this paper we study the promoting effect of a hydride source, molecular hydrogen, water and p-toluenesulfonic acid (TsOH) and the inhibiting effect of p-benzoquinone. On the basis of experimental evidences, of the two possible initial steps of the catalytic cycle, the insertion of the olefin into a Pd–H species or into a Pd–OCH3 species, it is suggested that the first plays a more important role.
Effect of hydride source ( water, hydrogen, p-toluensulfonic) on the hydroesterification of ethylene to methyl propionate using a Pd(PPh3)2(TsO)2 (TsO= p-toluensulfonate anion) catalyst precursor
CAVINATO, GIANNI;
2001
Abstract
Hydroesterification of ethylene to methyl propionate has been studied using the catalyst precursor Pd(PPh3)2(TsO)2, which is active in presence of PPh3 and TsOH (TOF = 5700 h−1 at 120◦C, 40 atm (CO/C2H4 = 1/1), Pd/PPh3/TsOH = 1/8/10, [Pd] = 2 × 10−3 mol l−1, solvent methanol, H2O = 800 ppm). In this paper we study the promoting effect of a hydride source, molecular hydrogen, water and p-toluenesulfonic acid (TsOH) and the inhibiting effect of p-benzoquinone. On the basis of experimental evidences, of the two possible initial steps of the catalytic cycle, the insertion of the olefin into a Pd–H species or into a Pd–OCH3 species, it is suggested that the first plays a more important role.
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