The kinetics of Cu ion exchange on Na-montmorillonite clay mineral has been investigated at three temperatures, in three solvents: H2O, ethylene glycol and glycerol. Solvent effects on the reaction rate have been disc...The kinetics of Cu ion exchange on Na-montmorillonite clay mineral has been investigated at three temperatures, in three solvents: H2O, ethylene glycol and glycerol. Solvent effects on the reaction rate have been discussed. The thermodynamic activation parameters were calculated and discussed in terms of solvation effects. The determined isokinetic temperature indicates that the reaction is enthalpy controlled where the interaction between solvent and clay surface plays an important role. A reaction mechanism which describes the solvent effect on the rate of Cu ion exchange is proposed.展开更多
Stable s-butyl n-heptafluorobutyryl nitroxide 3 has been generated in an electron transfer reaction in F113 ( CFCl2CF2Cl ) solution at r.t. The aN values for 3 in 11 aprotic solvents show a linear correlation with cy...Stable s-butyl n-heptafluorobutyryl nitroxide 3 has been generated in an electron transfer reaction in F113 ( CFCl2CF2Cl ) solution at r.t. The aN values for 3 in 11 aprotic solvents show a linear correlation with cybotactic solvent parameters ET and Z. The physical significance for slopes, slope×ET or slope×Z, and the extrapolated intercepts on the aN axis are well established. The plots of aN versus noncybotactic solvent parameters, such as dipolar moment and dielectric constant, are badly behaved.展开更多
The sustainable synthesis of dimethyl maleate via diesterification through the utilization of ionic liquid(IL)is of great importance.However,the relationship between the ILs nature and the reactivity of diesterificati...The sustainable synthesis of dimethyl maleate via diesterification through the utilization of ionic liquid(IL)is of great importance.However,the relationship between the ILs nature and the reactivity of diesterification is still unclear.Herein,a series of ILs with different structures were selected for the comprehensive investigation of diesterification.The acidity(H_(0))and Kamlet-Taft solvent parameters(hydrogen bond donor ability(α),hydrogen bond acceptor ability(β),and polarizability(π^(*)))of ILs were measured by UV–Visible spectroscopy,and the effects of them on the diesterification of maleic anhydride were also studied in detail.The results indicated that not only H0of the IL-based catalysis system,but also itsα,β,andπ^(*)influenced the reaction activity of diesterification.Furthermore,a quantifiable correlation was fitted between the natural logarithm of the rate constant and multiple parameters of ILs,indicating that the diesterification rate had a positive correlation with the H0,α,andπ^(*),and inverse correlation with theβof the IL.A plausible synergetic reaction mechanism for the excellent performance of[(HSO_(3))PMim][HSO_(4)]has been proposed.Overall,this work thoroughly explored the relationship between the nature of ILs on diesterification in-depth,which will reveal the nature of diesterification in detail.展开更多
文摘The kinetics of Cu ion exchange on Na-montmorillonite clay mineral has been investigated at three temperatures, in three solvents: H2O, ethylene glycol and glycerol. Solvent effects on the reaction rate have been discussed. The thermodynamic activation parameters were calculated and discussed in terms of solvation effects. The determined isokinetic temperature indicates that the reaction is enthalpy controlled where the interaction between solvent and clay surface plays an important role. A reaction mechanism which describes the solvent effect on the rate of Cu ion exchange is proposed.
文摘Stable s-butyl n-heptafluorobutyryl nitroxide 3 has been generated in an electron transfer reaction in F113 ( CFCl2CF2Cl ) solution at r.t. The aN values for 3 in 11 aprotic solvents show a linear correlation with cybotactic solvent parameters ET and Z. The physical significance for slopes, slope×ET or slope×Z, and the extrapolated intercepts on the aN axis are well established. The plots of aN versus noncybotactic solvent parameters, such as dipolar moment and dielectric constant, are badly behaved.
基金supported by the National Natural Science Foundation of China(21878315)the National Key Research and Development Program of China(2017YFA0206803)+1 种基金the Key Programs of the Chinese Academy of Sciences(KFZD-SW-413)the Key Programs of Innovation Academy for Green Manufacture,CAS(IAGM2020C17)。
文摘The sustainable synthesis of dimethyl maleate via diesterification through the utilization of ionic liquid(IL)is of great importance.However,the relationship between the ILs nature and the reactivity of diesterification is still unclear.Herein,a series of ILs with different structures were selected for the comprehensive investigation of diesterification.The acidity(H_(0))and Kamlet-Taft solvent parameters(hydrogen bond donor ability(α),hydrogen bond acceptor ability(β),and polarizability(π^(*)))of ILs were measured by UV–Visible spectroscopy,and the effects of them on the diesterification of maleic anhydride were also studied in detail.The results indicated that not only H0of the IL-based catalysis system,but also itsα,β,andπ^(*)influenced the reaction activity of diesterification.Furthermore,a quantifiable correlation was fitted between the natural logarithm of the rate constant and multiple parameters of ILs,indicating that the diesterification rate had a positive correlation with the H0,α,andπ^(*),and inverse correlation with theβof the IL.A plausible synergetic reaction mechanism for the excellent performance of[(HSO_(3))PMim][HSO_(4)]has been proposed.Overall,this work thoroughly explored the relationship between the nature of ILs on diesterification in-depth,which will reveal the nature of diesterification in detail.
