Kinetics of cyclohexene hydrocarbalkoxylation with cyclohexanol catalyzed by the Pd(PPh3)2Cl2-PPh3-p-toluenesulfonic acid system

Kinetic aspects of the influence of concentrations of methanol and the trans-2,3-bis(diphenylphosphinomethyl)norbornane promoting additive on the hydrocarbomethoxylation of cyclohexene catalyzed by the Pd(OAc)2/p-toluenesulfonic acid system

“…In particular, a non-monotonic dependence of the reaction rate on the alcohol concentration was reported for hydrocarbomethoxylation of cyclohexene in toluene catalyzed by the Pd(OAc) 2 /PPh 3 /ptoluenesulfonic acid system [14]. When the Pd(PPh 3 ) 2 Cl 2 /PPh 3 /p-toluenesulfonic acid catalytic system was used, non-monotonic dependences of the cyclohexene hydrocarboalkoxylation rate on the concentrations of methanol [10,11] and cyclohexanol [12,13] for reactions carried out in toluene were elucidated. Meanwhile, the hydrocarboalkoxylation of cyclohexene with various alcohols carried out in acetone and catalyzed by the Pd(PPh 3 ) 2 (TsO) 2 /PPh 3 /p-toluenesulfonic acid system followed first order kinetics [9].…”

“…For example, in [8], the hydrocarboalkoxylation of cyclohexene was reported to have a zeroth order character with respect to methanol, the reaction being catalyzed by PdCl 2 /PPh 3 /HCl, while in another publication [9], first order dependence was established for the same reaction catalyzed by Pd(PPh 3 ) 2 (TsO) 2 /PPh 3 /TsOH. A non-monotonic pattern of dependences of the hydrocarboalkoxylation rate on the methanol or cyclohexanol concentration was observed for catalysis by Pd(PPh 3 ) 2 Cl 2 /PPh 3 /TsOH [10][11][12][13] and Pd(OAc) 2 /PPh 3 /TsOH [14]. The ascending branches of the non-monotonic curves at low alcohol concentrations were attributed to the action of alcohol as a reactant according to the mass action law, whereas the descending branches were interpreted as being due to the formation of inactive or low-active ''ballast'' forms of the palladium catalyst under the action of excess alcohol [7,[10][11][12][13][14].…”

“…A non-monotonic pattern of dependences of the hydrocarboalkoxylation rate on the methanol or cyclohexanol concentration was observed for catalysis by Pd(PPh 3 ) 2 Cl 2 /PPh 3 /TsOH [10][11][12][13] and Pd(OAc) 2 /PPh 3 /TsOH [14]. The ascending branches of the non-monotonic curves at low alcohol concentrations were attributed to the action of alcohol as a reactant according to the mass action law, whereas the descending branches were interpreted as being due to the formation of inactive or low-active ''ballast'' forms of the palladium catalyst under the action of excess alcohol [7,[10][11][12][13][14]. The descending branches of the curves for hydrocarboalkoxylation rate plotted versus the concentrations of organophosphines PPh 3 [10,[12][13][14][15] and TBDPN [7] and slower increase in the reaction rate at higher methanol concentrations [7] were interpreted in a similar way.…”

“…The descending branches of the curves for hydrocarboalkoxylation rate plotted versus the concentrations of organophosphines PPh 3 [10,[12][13][14][15] and TBDPN [7] and slower increase in the reaction rate at higher methanol concentrations [7] were interpreted in a similar way. As shown in a number of papers [11,13,15], studies of the temperature effect on the reaction rate provide a thermodynamic substantiation of the possible formation of inert ''ballast'' forms of the catalyst in the system and serves to compare stabilities of these species under the reaction conditions. In this connection, the present paper gives the results of systematic kinetic studies of the hydrocarbomethoxylation of cyclohexene catalyzed by the Pd(OAc) 2 /TsOH/ TBDPN system with determination of the temperature dependence of the effective rate constants of the reaction.…”

“…The ascending branches of the non-monotonic curves at low alcohol concentrations were attributed to the action of alcohol as a reactant according to the mass action law, whereas the descending branches were interpreted as being due to the formation of inactive or low-active ''ballast'' forms of the palladium catalyst under the action of excess alcohol [7,[10][11][12][13][14]. The descending branches of the curves for hydrocarboalkoxylation rate plotted versus the concentrations of organophosphines PPh 3 [10,[12][13][14][15] and TBDPN [7] and slower increase in the reaction rate at higher methanol concentrations [7] were interpreted in a similar way. As shown in a number of papers [11,13,15], studies of the temperature effect on the reaction rate provide a thermodynamic substantiation of the possible formation of inert ''ballast'' forms of the catalyst in the system and serves to compare stabilities of these species under the reaction conditions.…”