Extractability and extraction mechanism of lanthanide ions were investigated by using a new extractant,N,Nn,N′,N′-tetrabutyl-3-oxa-diglycolamide(TBDGA),in toluene from nitric acid media.The effects of HNO_3 and TBDG...Extractability and extraction mechanism of lanthanide ions were investigated by using a new extractant,N,Nn,N′,N′-tetrabutyl-3-oxa-diglycolamide(TBDGA),in toluene from nitric acid media.The effects of HNO_3 and TBDGA concentrations,and temperature,on extraction of lanthanide ions were studied.Stoichiometrics of the main extracted species were HNO_3·TBDGA and M(NO_3)_3-3TBDGA(M = Er,Dy,Tb,Gd,La,Ce,Nd,Sm and Eu).The extracted species for metal ions were established to be ionic complex.In this complex,nitrate anion was not coordinated to the central ion.The extraction pattern increased gradually across the lanthanide ions series,showing enhanced affinity of TBDGA toward heavy lanthanide ions.Thermodynamic parameters were investigated for the exothermic extraction reaction.展开更多
The reaction of ethyl α-bromocinnamates with tetrabutyl ammonium fluoride（TBAF） was influenced largely by the position of the substituent at the phenyl ring.While the substrates without an ortho substituent at the ...The reaction of ethyl α-bromocinnamates with tetrabutyl ammonium fluoride（TBAF） was influenced largely by the position of the substituent at the phenyl ring.While the substrates without an ortho substituent at the phenyl ring were transformed to the corresponding β-fluoro ethyl cinnamates under the reaction conditions,the presence of an ortho substituent only resulted in the formation of ethyl 3-phenylpropiolate derivatives.The reaction of ethyl 2-bromo-3-（4-methoxyphenyl） acrylate also failed to deliver the hydrofluorination product due to the electron-donating effect of the methoxy group.展开更多
The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl ca...The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl carbonate (MPC) which is an intermediate of the reaction. The selectivity for DPC was improved when increasing the phenol/DMC molar ratio or prolonging the reaction time. The phenol conversion, selectivity for MPC and DPC were 47 4%, 90 9% and 9 14%, respectively, when the transesterification reaction approached equilibrium under the conditions of 175 ℃, 25 h and DMC∶phenol∶ Ti(OBu) 4 molar ratio of 1 5∶1∶0 05. The selectivity for DPC could reach 12.2% when the reaction time was 30 h. The tetrabutyl titanate catalyst showed a higher catalytic activity than tetraphenyl titanate.展开更多
The synthesis of titanosilicalite has become a hotspot in the zeolite catalytic fields. In this paper, TS 1 zeolite samples were synthesized with tetrapropyl ammonium bromide as the template, with ammonia as the base ...The synthesis of titanosilicalite has become a hotspot in the zeolite catalytic fields. In this paper, TS 1 zeolite samples were synthesized with tetrapropyl ammonium bromide as the template, with ammonia as the base source and with the mixture of titanium tetrachloride and tetrabutyl orthotitanate as the titanium source. The TS 1 samples have excellent catalytic performance in epoxidation of propylene with aqueous hydrogen peroxide. The samples were characterized by XRD and IR. The introduction of chlorine decreases the association degree of titanium alkoxides and it may prevent preferential segregation of titanium and silicon.展开更多
基金supported by the National Natural Science Foundation of China(21077044)Natural Science Foundation of Shandong Province(ZR2015BM030)
文摘Extractability and extraction mechanism of lanthanide ions were investigated by using a new extractant,N,Nn,N′,N′-tetrabutyl-3-oxa-diglycolamide(TBDGA),in toluene from nitric acid media.The effects of HNO_3 and TBDGA concentrations,and temperature,on extraction of lanthanide ions were studied.Stoichiometrics of the main extracted species were HNO_3·TBDGA and M(NO_3)_3-3TBDGA(M = Er,Dy,Tb,Gd,La,Ce,Nd,Sm and Eu).The extracted species for metal ions were established to be ionic complex.In this complex,nitrate anion was not coordinated to the central ion.The extraction pattern increased gradually across the lanthanide ions series,showing enhanced affinity of TBDGA toward heavy lanthanide ions.Thermodynamic parameters were investigated for the exothermic extraction reaction.
文摘The reaction of ethyl α-bromocinnamates with tetrabutyl ammonium fluoride（TBAF） was influenced largely by the position of the substituent at the phenyl ring.While the substrates without an ortho substituent at the phenyl ring were transformed to the corresponding β-fluoro ethyl cinnamates under the reaction conditions,the presence of an ortho substituent only resulted in the formation of ethyl 3-phenylpropiolate derivatives.The reaction of ethyl 2-bromo-3-（4-methoxyphenyl） acrylate also failed to deliver the hydrofluorination product due to the electron-donating effect of the methoxy group.
文摘The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl carbonate (MPC) which is an intermediate of the reaction. The selectivity for DPC was improved when increasing the phenol/DMC molar ratio or prolonging the reaction time. The phenol conversion, selectivity for MPC and DPC were 47 4%, 90 9% and 9 14%, respectively, when the transesterification reaction approached equilibrium under the conditions of 175 ℃, 25 h and DMC∶phenol∶ Ti(OBu) 4 molar ratio of 1 5∶1∶0 05. The selectivity for DPC could reach 12.2% when the reaction time was 30 h. The tetrabutyl titanate catalyst showed a higher catalytic activity than tetraphenyl titanate.
文摘The synthesis of titanosilicalite has become a hotspot in the zeolite catalytic fields. In this paper, TS 1 zeolite samples were synthesized with tetrapropyl ammonium bromide as the template, with ammonia as the base source and with the mixture of titanium tetrachloride and tetrabutyl orthotitanate as the titanium source. The TS 1 samples have excellent catalytic performance in epoxidation of propylene with aqueous hydrogen peroxide. The samples were characterized by XRD and IR. The introduction of chlorine decreases the association degree of titanium alkoxides and it may prevent preferential segregation of titanium and silicon.
