The alkylation mechanism catalyzed by an ionic liquid （as a Lewis acid） may be different from the traditional alkylation mechanism catalyzed by Br nsted acid,especially as their initiation steps are still not clear....The alkylation mechanism catalyzed by an ionic liquid （as a Lewis acid） may be different from the traditional alkylation mechanism catalyzed by Br nsted acid,especially as their initiation steps are still not clear.In this paper,an isotope exchange method is used to investigate the catalytic mechanism of AlCl 3 /butyl-methyl-imidazolium chloride ionic liquid in the alkylation of benzene with 1-dodecene.The proposed catalytic mechanism was confirmed by analysis of ionic liquid before and after reaction and of the alkylation products of deuterated benzene （C 6 D 6） with 1-dodecene.The proposed mechanism consists of the equilibrium reaction between [Al 2 Cl 7 ] ＋H ＋ and [AlHCl 3 ] ＋ ＋[AlCl 4 ],in which the Br nsted acid [AlHCl 3 ] ＋ is supplied by the reaction of 2-H on the imidazolium ring and [Al 2 Cl 7 ].The alkylation reaction is initiated by the Br nsted acid [AlHCl 3 ] ＋ which reacts with 1-dodecene to form a carbonium ion,then the carbonium ion reacts with benzene to form an unstable σ complex,leading to the formation of 2-phenyldodecane.展开更多
Systematic analysis about the exploitation of imidazolium based ionic liquids （ILs）, [BMIM] BF4 [ILl], [EMIM] BF4 ILL2] and [BMIM] PF6 [IL3] as the morphological template on the basic sol-gel method adopted synthesi...Systematic analysis about the exploitation of imidazolium based ionic liquids （ILs）, [BMIM] BF4 [ILl], [EMIM] BF4 ILL2] and [BMIM] PF6 [IL3] as the morphological template on the basic sol-gel method adopted synthesis of nanostructured zinc oxide （ZnO） is presented. X-ray diffraction （XRD）, particle size analysis （PSA） and scanning electron microscopy （SEM） have been employed for the characterization of structure and morphology of the synthesized ZnO particles. Well-defined capsule like shaped morphology with lower nanosize is observed for the ZnO nanoparticles with ILl than those with IL2 and IL3. This confirms that ILl served as an effective templating material due to their unique properties. Especially the effective aggregation of ZnO particles with a self-organized frame of ILl was the essential factor to produce the lower nanosized ZnO with capsule shaped structure. The synthesized ZnO samples with IL2 and IL3 fabricated the flake like shaped and rod like shaped morphologies in the range of nanoscale. The formed ZnO nanoparticles with IL2 exhibit higher nanosize than the ZnO nanoparticles produced by ILl, owing to shorter length of alkyl group in its cation which restricts steric effect and permits the nanoparticles to grow longer. Even though IL3 produced the discrete ZnO nanorods, the hydrophobic nature of IL3 created the higher nanosize than the ZnO nanoparticles formed by other two ionic liquids. Antibacterial properties of the synthesized ZnO nanostructures were investigated against Staphylococcus aureus （gram positive） and Escherichia coil （gram negative） bacteria by Agar diffusion test method. Microbial experiments indicate that the synthesized ZnO samples show a wide spectrum of antimicrobial activities and performed better against S. aureus than E. coil with the same concentration of ZnO.展开更多
Development of a predictive tool for H_2S solubility estimation can be very helpful in gas sweetening industry. Experimental databases on H_2 S solubility were rarely available, so as reliable predictive models. Thus,...Development of a predictive tool for H_2S solubility estimation can be very helpful in gas sweetening industry. Experimental databases on H_2 S solubility were rarely available, so as reliable predictive models. Thus, in this study the H_2 S solubility database was established, and then a Least-Squares Support Vector Machine(LSSVM) approach based on the established database is proposed. Group contribution method was also applied to eliminate the model's dependence on experimental data. Accordingly, our proposed LSSVM model can predict H_2 S solubility as a function of temperature, pressure, and 15 different chemical structures of Ionic liquids(ILs). Root Mean Square Error(RMSE) and coefficient of determination(R^2) are 0.0122 and 0.9941, respectively. Moreover, comparison of our model with other existing models showed its reliability for H_2 S solubility in ILs. This can be very useful for engineers dealing with gas sweetening process in different applications of analysis, simulation, and designation.展开更多
In this study, a modified silica gel surface with a hydrophobic ionic liquid (SG-1,10-PhenanNTf2) was used as an adsorbent for a selective extraction of coumarin prior to its determination by use of high performance l...In this study, a modified silica gel surface with a hydrophobic ionic liquid (SG-1,10-PhenanNTf2) was used as an adsorbent for a selective extraction of coumarin prior to its determination by use of high performance liquid chromatography. Results demonstrated that SG-1,10-PhenanNTf2 phase had a good adsorption capacity up to 85.29 mg?g?1, high selectivity, good site accessibility and fast binding kinetics toward coumarin. The adsorption capacity for coumarin was improved by 62.33% with the SG-1,10-PhenanNTf2 phase as compared to activated silica gel. Adsorption isotherm data displayed that the adsorption process was mainly monolayer on a homogeneous adsorbent surface, confirming the validity of Langmuir adsorption isotherm model. The adsorption of coumarin on the SG-1,10-PhenanNTf2 phase was accomplished after only 60 min contact time. Results of kinetic models showed that the adsorption of coumarin on the SG-1,10-PhenanNTf2 phase obeyed a pseudo second-order kinetic model. Finally, the efficiency of this methodology was confirmed by applying it to real water samples.展开更多
离子液体(ILs)具有高稳定性、溶解性能好、可设计性、易回收等优点,尤其因高CO_(2)溶解度在碳捕集方面显示了巨大潜力。但由于ILs种类繁多且价格昂贵,依靠实验研究耗时费力,因此构建ILs体系的热力学预测模型至关重要。UNIFAC模型在ILs...离子液体(ILs)具有高稳定性、溶解性能好、可设计性、易回收等优点,尤其因高CO_(2)溶解度在碳捕集方面显示了巨大潜力。但由于ILs种类繁多且价格昂贵,依靠实验研究耗时费力,因此构建ILs体系的热力学预测模型至关重要。UNIFAC模型在ILs气体分离工艺设计与优化领域具有重要的理论价值和工程应用意义,基于此,本研究构建了应用于ILs-CO_(2)体系活度系数预测的UNIFAC模型。本文系统收集了CO_(2)在ILs中的溶解度实验数据,并结合相平衡计算出活度系数,建立了ILs-CO_(2)体系活度系数数据库。采用COSMO方法和van der Waals规则分别获得了UNIFAC模型中基团的重要参数(R_(k)和Q_(k))。基于实验值,拟合了UNIFAC相互作用参数。通过平均相对误差(AARD),比较了两种方法建立的UNIFAC模型的预测效果。结果表明:通过COSMO方法(AARD=7.68%)建立的UNIFAC模型对ILs-CO_(2)体系的活度系数预测误差比van der Waals方法(AARD=12.57%)降低了4.89个百分点。并在此基础上建立了ILs-CO_(2)体系UNIFAC模型,获得了近100对基团的相互作用参数数据库。由于UNIFAC模型的基团贡献特点,本工作建立的UNIFAC模型可预测数据库中包含的基团组成的新型ILs与CO_(2)体系的活度系数,从而为后续ILs法气体吸收的分子设计奠定了扎实基础。展开更多
A novel method for fluorination of halopyridazine derivatives with potassium fluoride was performed using a green chemistry procedure, including ionic liquid as an environmentally benign reaction medium and microwave ...A novel method for fluorination of halopyridazine derivatives with potassium fluoride was performed using a green chemistry procedure, including ionic liquid as an environmentally benign reaction medium and microwave irradiation with high yield.展开更多
基金financial support from the National Natural Science Foundation of China (NSFC,2052010)
文摘The alkylation mechanism catalyzed by an ionic liquid （as a Lewis acid） may be different from the traditional alkylation mechanism catalyzed by Br nsted acid,especially as their initiation steps are still not clear.In this paper,an isotope exchange method is used to investigate the catalytic mechanism of AlCl 3 /butyl-methyl-imidazolium chloride ionic liquid in the alkylation of benzene with 1-dodecene.The proposed catalytic mechanism was confirmed by analysis of ionic liquid before and after reaction and of the alkylation products of deuterated benzene （C 6 D 6） with 1-dodecene.The proposed mechanism consists of the equilibrium reaction between [Al 2 Cl 7 ] ＋H ＋ and [AlHCl 3 ] ＋ ＋[AlCl 4 ],in which the Br nsted acid [AlHCl 3 ] ＋ is supplied by the reaction of 2-H on the imidazolium ring and [Al 2 Cl 7 ].The alkylation reaction is initiated by the Br nsted acid [AlHCl 3 ] ＋ which reacts with 1-dodecene to form a carbonium ion,then the carbonium ion reacts with benzene to form an unstable σ complex,leading to the formation of 2-phenyldodecane.
基金Department of Science and Technology (DST) for the financial support from DST-PURSE programme
文摘Systematic analysis about the exploitation of imidazolium based ionic liquids （ILs）, [BMIM] BF4 [ILl], [EMIM] BF4 ILL2] and [BMIM] PF6 [IL3] as the morphological template on the basic sol-gel method adopted synthesis of nanostructured zinc oxide （ZnO） is presented. X-ray diffraction （XRD）, particle size analysis （PSA） and scanning electron microscopy （SEM） have been employed for the characterization of structure and morphology of the synthesized ZnO particles. Well-defined capsule like shaped morphology with lower nanosize is observed for the ZnO nanoparticles with ILl than those with IL2 and IL3. This confirms that ILl served as an effective templating material due to their unique properties. Especially the effective aggregation of ZnO particles with a self-organized frame of ILl was the essential factor to produce the lower nanosized ZnO with capsule shaped structure. The synthesized ZnO samples with IL2 and IL3 fabricated the flake like shaped and rod like shaped morphologies in the range of nanoscale. The formed ZnO nanoparticles with IL2 exhibit higher nanosize than the ZnO nanoparticles produced by ILl, owing to shorter length of alkyl group in its cation which restricts steric effect and permits the nanoparticles to grow longer. Even though IL3 produced the discrete ZnO nanorods, the hydrophobic nature of IL3 created the higher nanosize than the ZnO nanoparticles formed by other two ionic liquids. Antibacterial properties of the synthesized ZnO nanostructures were investigated against Staphylococcus aureus （gram positive） and Escherichia coil （gram negative） bacteria by Agar diffusion test method. Microbial experiments indicate that the synthesized ZnO samples show a wide spectrum of antimicrobial activities and performed better against S. aureus than E. coil with the same concentration of ZnO.
文摘Development of a predictive tool for H_2S solubility estimation can be very helpful in gas sweetening industry. Experimental databases on H_2 S solubility were rarely available, so as reliable predictive models. Thus, in this study the H_2 S solubility database was established, and then a Least-Squares Support Vector Machine(LSSVM) approach based on the established database is proposed. Group contribution method was also applied to eliminate the model's dependence on experimental data. Accordingly, our proposed LSSVM model can predict H_2 S solubility as a function of temperature, pressure, and 15 different chemical structures of Ionic liquids(ILs). Root Mean Square Error(RMSE) and coefficient of determination(R^2) are 0.0122 and 0.9941, respectively. Moreover, comparison of our model with other existing models showed its reliability for H_2 S solubility in ILs. This can be very useful for engineers dealing with gas sweetening process in different applications of analysis, simulation, and designation.
文摘In this study, a modified silica gel surface with a hydrophobic ionic liquid (SG-1,10-PhenanNTf2) was used as an adsorbent for a selective extraction of coumarin prior to its determination by use of high performance liquid chromatography. Results demonstrated that SG-1,10-PhenanNTf2 phase had a good adsorption capacity up to 85.29 mg?g?1, high selectivity, good site accessibility and fast binding kinetics toward coumarin. The adsorption capacity for coumarin was improved by 62.33% with the SG-1,10-PhenanNTf2 phase as compared to activated silica gel. Adsorption isotherm data displayed that the adsorption process was mainly monolayer on a homogeneous adsorbent surface, confirming the validity of Langmuir adsorption isotherm model. The adsorption of coumarin on the SG-1,10-PhenanNTf2 phase was accomplished after only 60 min contact time. Results of kinetic models showed that the adsorption of coumarin on the SG-1,10-PhenanNTf2 phase obeyed a pseudo second-order kinetic model. Finally, the efficiency of this methodology was confirmed by applying it to real water samples.
文摘离子液体(ILs)具有高稳定性、溶解性能好、可设计性、易回收等优点,尤其因高CO_(2)溶解度在碳捕集方面显示了巨大潜力。但由于ILs种类繁多且价格昂贵,依靠实验研究耗时费力,因此构建ILs体系的热力学预测模型至关重要。UNIFAC模型在ILs气体分离工艺设计与优化领域具有重要的理论价值和工程应用意义,基于此,本研究构建了应用于ILs-CO_(2)体系活度系数预测的UNIFAC模型。本文系统收集了CO_(2)在ILs中的溶解度实验数据,并结合相平衡计算出活度系数,建立了ILs-CO_(2)体系活度系数数据库。采用COSMO方法和van der Waals规则分别获得了UNIFAC模型中基团的重要参数(R_(k)和Q_(k))。基于实验值,拟合了UNIFAC相互作用参数。通过平均相对误差(AARD),比较了两种方法建立的UNIFAC模型的预测效果。结果表明:通过COSMO方法(AARD=7.68%)建立的UNIFAC模型对ILs-CO_(2)体系的活度系数预测误差比van der Waals方法(AARD=12.57%)降低了4.89个百分点。并在此基础上建立了ILs-CO_(2)体系UNIFAC模型,获得了近100对基团的相互作用参数数据库。由于UNIFAC模型的基团贡献特点,本工作建立的UNIFAC模型可预测数据库中包含的基团组成的新型ILs与CO_(2)体系的活度系数,从而为后续ILs法气体吸收的分子设计奠定了扎实基础。
文摘A novel method for fluorination of halopyridazine derivatives with potassium fluoride was performed using a green chemistry procedure, including ionic liquid as an environmentally benign reaction medium and microwave irradiation with high yield.
