The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlC...The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlCl and Et_2 AlCl alone for comparison. The Et_2 AlCl- induced polymer-ization gives a low yield while the polymerization initiated by organic chloride/Et_2 AlCl producesmainly insoluble product. In contrast, the polymerization with azide/Et,AlCl has a high conver-sion and the resulting polymer having a high molecular weight is totally soluble. The SEC spectraof the polymers have clearly shown the differences between these initiating systems.展开更多
The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title ...The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.展开更多
A novel and practical method for the synthesis of 3,5-bis(trifluoromethyl)-4,5-dihydro-1H-pyrazoles by [3+2] cycloaddition reactions of α-(trifluoromethyl)styrenes with 2,2,2-trifluorodiazoethane (CF3CHN2) has been d...A novel and practical method for the synthesis of 3,5-bis(trifluoromethyl)-4,5-dihydro-1H-pyrazoles by [3+2] cycloaddition reactions of α-(trifluoromethyl)styrenes with 2,2,2-trifluorodiazoethane (CF3CHN2) has been developed. The cyclization reaction proceeds smoothly in the presence of a catalytic amount of Et_(3)N, affording a variety of bis(trifluoromethyl)-substituted 2-pyrazolines in good to excellent yields. This method also exhibits a broad substrate scope and tolerates various functional groups.展开更多
Solid complexes,RE(Et_(2)dtc)_(3)(phen)(RE=La,Pr,Nd,Sm-Lu),were synthesized with sodium diethyldithiocarbamate(NaEt_(2)dtc3H_(2)O),1,10-phenanthroline(o-phen·H_(2)O)and hydrated lanthanide chlorides in absolute e...Solid complexes,RE(Et_(2)dtc)_(3)(phen)(RE=La,Pr,Nd,Sm-Lu),were synthesized with sodium diethyldithiocarbamate(NaEt_(2)dtc3H_(2)O),1,10-phenanthroline(o-phen·H_(2)O)and hydrated lanthanide chlorides in absolute ethanol.The constant-volume combustion energies of complexes,Δ_(c)U,were determined by a precise rotating-bomb calorimeter at 298.15 K.The standard enthalpies of combustion,Δ_(c)H^(θ)_(m),and standard enthalpies of formation,Δ_(f)H^(θ)_(m),were calculated for these complexes,respectively.The experiment results showed the'tripartite effect'of rare earth.展开更多
Tetrabutyl ammonium fluoride（TBAF） was found to be capable of catalyzing the intramolecular hydroalkoxylation of 6- hydroxyhex-2-ynoates and 7-hydroxyhept-2-ynoates.The reaction could be used to prepare 2,5-substitu...Tetrabutyl ammonium fluoride（TBAF） was found to be capable of catalyzing the intramolecular hydroalkoxylation of 6- hydroxyhex-2-ynoates and 7-hydroxyhept-2-ynoates.The reaction could be used to prepare 2,5-substituted THF rings and 2,6- substituted THP rings.展开更多
文摘The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlCl and Et_2 AlCl alone for comparison. The Et_2 AlCl- induced polymer-ization gives a low yield while the polymerization initiated by organic chloride/Et_2 AlCl producesmainly insoluble product. In contrast, the polymerization with azide/Et,AlCl has a high conver-sion and the resulting polymer having a high molecular weight is totally soluble. The SEC spectraof the polymers have clearly shown the differences between these initiating systems.
文摘The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.
基金support from the National Key Research and Development Program of China(No.2017YFD0200505)。
文摘A novel and practical method for the synthesis of 3,5-bis(trifluoromethyl)-4,5-dihydro-1H-pyrazoles by [3+2] cycloaddition reactions of α-(trifluoromethyl)styrenes with 2,2,2-trifluorodiazoethane (CF3CHN2) has been developed. The cyclization reaction proceeds smoothly in the presence of a catalytic amount of Et_(3)N, affording a variety of bis(trifluoromethyl)-substituted 2-pyrazolines in good to excellent yields. This method also exhibits a broad substrate scope and tolerates various functional groups.
基金supported by the National Natural Science Foundation of China(Grant No.20171036)Education Committee of Shaanxi Province(No.01JK229)Northwest University(02NW02)
文摘Solid complexes,RE(Et_(2)dtc)_(3)(phen)(RE=La,Pr,Nd,Sm-Lu),were synthesized with sodium diethyldithiocarbamate(NaEt_(2)dtc3H_(2)O),1,10-phenanthroline(o-phen·H_(2)O)and hydrated lanthanide chlorides in absolute ethanol.The constant-volume combustion energies of complexes,Δ_(c)U,were determined by a precise rotating-bomb calorimeter at 298.15 K.The standard enthalpies of combustion,Δ_(c)H^(θ)_(m),and standard enthalpies of formation,Δ_(f)H^(θ)_(m),were calculated for these complexes,respectively.The experiment results showed the'tripartite effect'of rare earth.
基金the National Natural Science Foundation of China(No.20772053)the Fundamental Research Funds for the Central Universities(No.223-860102)for financial support
文摘Tetrabutyl ammonium fluoride（TBAF） was found to be capable of catalyzing the intramolecular hydroalkoxylation of 6- hydroxyhex-2-ynoates and 7-hydroxyhept-2-ynoates.The reaction could be used to prepare 2,5-substituted THF rings and 2,6- substituted THP rings.
