In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals) pentaerythritol using SOH-functionalized ionic liquids(ILs) as catalysts was reported.The ILs show high...In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals) pentaerythritol using SOH-functionalized ionic liquids(ILs) as catalysts was reported.The ILs show high catalytic activity and reusability with good to excellent yields of the desired products.Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction.Maximum product yield of 93%was observed on using[PSPy][OTf]as catalyst and it can be reused at least 8 times without obvious activity loss.展开更多
The effects of organic salts on 1,3,5-trioxane synthesis were investigated through batch reaction and continuous production experiments. The organic salts used include sodium methanesulfonate（CH3NaO3S）, sodium benze...The effects of organic salts on 1,3,5-trioxane synthesis were investigated through batch reaction and continuous production experiments. The organic salts used include sodium methanesulfonate（CH3NaO3S）, sodium benzenesulfonate（C6H5NaO3S）, sodium 4-methylbenzenesulfonate（C7H7NaO3S）, and sodium 3-nitrobenzene sulfonate（C6H4NNaO5S）. It was shown that the effects of organic salts on the yield of 1,3,5-trioxane in reaction solution and distillate follow the order CH3NaO3S ／C6H5NaO3S／C7H7NaO3S／C6H4NNaO5S, which is inversely related to the charge density of the anions of the organic salts. In comparison with Cl–-based salts such as magnesium chloride, organic salts have the advantages of less formic acid generation and low corrosion. Studies on water activity revealed that the effect of organic salts on the activity of water was quite small at low concentration of organic salts. UV–visible spectroscopy and vapor–liquid equilibrium experiments were performed to uncover the mechanisms that govern such effects. The results showed that the effect of organic salts on the yield of 1,3,5-trioxane relies primarily on their ability to increase the catalytic activity of sulfuric acid and increase the relative volatilities of 1,3,5-trioxane and water and of 1,3,5-trioxane and oligomers.展开更多
The batch reaction experiments have been made for the first time to investigate the effect of ionic structure on the reactivity and selectivity of the trioxane-forming reaction catalyzed by a Br?nsted-acidic ionic liq...The batch reaction experiments have been made for the first time to investigate the effect of ionic structure on the reactivity and selectivity of the trioxane-forming reaction catalyzed by a Br?nsted-acidic ionic liquid(IL).The ILs considered include 1-cyclohexyl-2-pyrrolidinonium trifluoromethanesulfonate([NCy P][TfO ]),1-cyclohexyl-2-pyrrolidinonium benzenesulfonate([NCyP ][BSA]),1-cyclohexyl-2-pyrrolidinonium p-toluenesulfonate([NCyP ][pTSA]),1-octyl-2-pyrrolidinonium 2,4-dinitrobenzenesulfonate([NOP][DNBSA]),1-octyl-2-pyrrolidinonium benzenesulfonate([NOP][BSA]),1-octyl-2-pyrrolidinonium methanesulfonate([NOP][MSA]),and 1-octyl-2-pyrrolidinonium trifluoromethanesulfonate([NOP][Tf O]).It is found that the yield of trioxane in the reaction solution correlates inversely with the Hammett acidity function H0 of the aqueous solution of the corresponding ILs.Variation of the cation structure from [NCyP ]+to [NOP]+exerts little influence on the yield and the selectivity of trioxane in the reaction solution.Using [TfO ]-or [DNBSA]-in place of [MSA]-or [BSA]-apparently increases the yield of trioxane,but only slightly increases the concentration of formic acid in the reaction solution.The continuous production experiments have been made to investigate the performance of [NOP][MSA],[NOP][DNBSA],[NCyP ][TfO ],and H2SO4 as an extraction distillation agent.Such effect of [NCyP ][TfO ] considerably overrides that of H2SO4.The yield and the selectivity of trioxane are both increased when [NCyP ][TfO ] is used instead of H2SO4 at a reaction time 5 h.展开更多
在这篇文章，新奇 bi-SO3H-functionalized IL 的系列用简单、有效、经济的过程被综合。Hammett 方法被用来决定这些离子的液体的酸味顺序，并且 bi-SO3H-functionalized IL 的酸味比传统的 single-SO3H-functionalized IL 的强壮。他们...在这篇文章，新奇 bi-SO3H-functionalized IL 的系列用简单、有效、经济的过程被综合。Hammett 方法被用来决定这些离子的液体的酸味顺序，并且 bi-SO3H-functionalized IL 的酸味比传统的 single-SO3H-functionalized IL 的强壮。他们在 N-(3 苯基)-3-oxo-1-(phenylpropyl)acetamide 的合成的催化活动被调查，他们与他们的酸味历久不渝。展开更多
Frustrated Lewis pairs（FLPs） emerge as a new type of bifunctional metal-free catalysts for reversible H_2 activation, which is important for the storage and liberation of H_2 or further controllable utilizing chemic...Frustrated Lewis pairs（FLPs） emerge as a new type of bifunctional metal-free catalysts for reversible H_2 activation, which is important for the storage and liberation of H_2 or further controllable utilizing chemical fuels via hydrogenation/dehydrogenation. Herein, a DFT study was conducted to understand the geometric factors and electronic effects of FLPs on reversible H_2 activation. The Lewis base group mainly contributes to the proton attachment, and influences the kinetics of the H_2 activation. The Lewis acid group mainly relates to the hydride attachment, and affects more significantly on the thermodynamics of H_2 activation. The dimer and quenched structure of FLPs also have a degree of influence on the performance of catalyzed H_2 activation. A series of FLPs with para-substituted phenyl derivatives as LA groups were designed and evaluated. The results indicate that the variation of LA groups has significant impact on thermodynamic energy of dihydrogen adducts but insignificant effect on kinetics. Moreover,we found the thermodynamic energy of products has a good linear relationship with Hammett substituent constants. The solvent effect on H_2 activation was also studied, and polar solvent is beneficial for zwitterionic products. These results should provide deeper insight to understand the relation between FLPs structure and reactivity, which is critical for rational design of more efficient FLPs catalysts for reversible H_2 activation.展开更多
基金HUANG Ying was supported by the Natural Science Foundation of Hunan Province,China (11JJ5065)Hunan College Student Research Study,Innovative Experiments,China (Xiang Jiao Tong [2011] 272)+4 种基金"Twelfth Five-Year" Key Discipline of Hunan University of Chinese Medicine-Pharmaceutical Analysis Science,ChinaZHANG Peng-Fei was supported by the Funds from the Major New Drug Discovery Science and Technology,China (2012ZX09303013-06)National Natural Science Foundation of China (81272609)Public Health Department of Hunan Scientific Research Foundation,China (B2010-004)LIU Liang-Hong was supported by the 2012 Innovation Program of Hunan University of Chinese Medicine for Postgraduate Students,China (2012cx07)~~
基金supported by National 863 High-Tech Research and Development Program of China(No. 2007AA05Z101)
文摘In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals) pentaerythritol using SOH-functionalized ionic liquids(ILs) as catalysts was reported.The ILs show high catalytic activity and reusability with good to excellent yields of the desired products.Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction.Maximum product yield of 93%was observed on using[PSPy][OTf]as catalyst and it can be reused at least 8 times without obvious activity loss.
基金the National Natural Science Foundation of China (21576285 and 21276271)Science Foundation of China University of Petroleum, Beijing (qzdx-2011-01)
文摘The effects of organic salts on 1,3,5-trioxane synthesis were investigated through batch reaction and continuous production experiments. The organic salts used include sodium methanesulfonate（CH3NaO3S）, sodium benzenesulfonate（C6H5NaO3S）, sodium 4-methylbenzenesulfonate（C7H7NaO3S）, and sodium 3-nitrobenzene sulfonate（C6H4NNaO5S）. It was shown that the effects of organic salts on the yield of 1,3,5-trioxane in reaction solution and distillate follow the order CH3NaO3S ／C6H5NaO3S／C7H7NaO3S／C6H4NNaO5S, which is inversely related to the charge density of the anions of the organic salts. In comparison with Cl–-based salts such as magnesium chloride, organic salts have the advantages of less formic acid generation and low corrosion. Studies on water activity revealed that the effect of organic salts on the activity of water was quite small at low concentration of organic salts. UV–visible spectroscopy and vapor–liquid equilibrium experiments were performed to uncover the mechanisms that govern such effects. The results showed that the effect of organic salts on the yield of 1,3,5-trioxane relies primarily on their ability to increase the catalytic activity of sulfuric acid and increase the relative volatilities of 1,3,5-trioxane and water and of 1,3,5-trioxane and oligomers.
基金Supported by the National Natural Science Foundation of China(21576285,21276271)
文摘The batch reaction experiments have been made for the first time to investigate the effect of ionic structure on the reactivity and selectivity of the trioxane-forming reaction catalyzed by a Br?nsted-acidic ionic liquid(IL).The ILs considered include 1-cyclohexyl-2-pyrrolidinonium trifluoromethanesulfonate([NCy P][TfO ]),1-cyclohexyl-2-pyrrolidinonium benzenesulfonate([NCyP ][BSA]),1-cyclohexyl-2-pyrrolidinonium p-toluenesulfonate([NCyP ][pTSA]),1-octyl-2-pyrrolidinonium 2,4-dinitrobenzenesulfonate([NOP][DNBSA]),1-octyl-2-pyrrolidinonium benzenesulfonate([NOP][BSA]),1-octyl-2-pyrrolidinonium methanesulfonate([NOP][MSA]),and 1-octyl-2-pyrrolidinonium trifluoromethanesulfonate([NOP][Tf O]).It is found that the yield of trioxane in the reaction solution correlates inversely with the Hammett acidity function H0 of the aqueous solution of the corresponding ILs.Variation of the cation structure from [NCyP ]+to [NOP]+exerts little influence on the yield and the selectivity of trioxane in the reaction solution.Using [TfO ]-or [DNBSA]-in place of [MSA]-or [BSA]-apparently increases the yield of trioxane,but only slightly increases the concentration of formic acid in the reaction solution.The continuous production experiments have been made to investigate the performance of [NOP][MSA],[NOP][DNBSA],[NCyP ][TfO ],and H2SO4 as an extraction distillation agent.Such effect of [NCyP ][TfO ] considerably overrides that of H2SO4.The yield and the selectivity of trioxane are both increased when [NCyP ][TfO ] is used instead of H2SO4 at a reaction time 5 h.
基金the National Natural Science Foundation ofChina(Nos.21003049,21073064)the Fundamental Research Funds for the Central Universities for financial support
文摘在这篇文章，新奇 bi-SO3H-functionalized IL 的系列用简单、有效、经济的过程被综合。Hammett 方法被用来决定这些离子的液体的酸味顺序，并且 bi-SO3H-functionalized IL 的酸味比传统的 single-SO3H-functionalized IL 的强壮。他们在 N-(3 苯基)-3-oxo-1-(phenylpropyl)acetamide 的合成的催化活动被调查，他们与他们的酸味历久不渝。
基金supported by the National Natural Science Foundation of China (Nos. 21502023 and 21473261)the Guangdong Natural Science Funds for Distinguished Young Scholar(No. 2015A030306027)+1 种基金the Guangdong Special Support Plan for High-Level Talent(No. 20153100042090537)supported in part by the high performance grid computing platform of Sun Yat-sen University, the Guangdong Province Key Laboratory of Computational Science, and Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (No. U1501501)
文摘Frustrated Lewis pairs（FLPs） emerge as a new type of bifunctional metal-free catalysts for reversible H_2 activation, which is important for the storage and liberation of H_2 or further controllable utilizing chemical fuels via hydrogenation/dehydrogenation. Herein, a DFT study was conducted to understand the geometric factors and electronic effects of FLPs on reversible H_2 activation. The Lewis base group mainly contributes to the proton attachment, and influences the kinetics of the H_2 activation. The Lewis acid group mainly relates to the hydride attachment, and affects more significantly on the thermodynamics of H_2 activation. The dimer and quenched structure of FLPs also have a degree of influence on the performance of catalyzed H_2 activation. A series of FLPs with para-substituted phenyl derivatives as LA groups were designed and evaluated. The results indicate that the variation of LA groups has significant impact on thermodynamic energy of dihydrogen adducts but insignificant effect on kinetics. Moreover,we found the thermodynamic energy of products has a good linear relationship with Hammett substituent constants. The solvent effect on H_2 activation was also studied, and polar solvent is beneficial for zwitterionic products. These results should provide deeper insight to understand the relation between FLPs structure and reactivity, which is critical for rational design of more efficient FLPs catalysts for reversible H_2 activation.
