With the aim of achieving a high 5-hydroxymethylfurfural(HMF)yield from glucose with H-ZSM-5 catalyst at low cost,three inexpensive biphasic reaction systems,H2O?tetrahydrofuran(THF),H2O?2-methyltetrahydrofuran(MeTHF)...With the aim of achieving a high 5-hydroxymethylfurfural(HMF)yield from glucose with H-ZSM-5 catalyst at low cost,three inexpensive biphasic reaction systems,H2O?tetrahydrofuran(THF),H2O?2-methyltetrahydrofuran(MeTHF)and H2O?2-butanol,were discovered and proved to be particularly effective in promoting the formation of HMF from glucose over H-ZSM-5 zeolite.In order to determine the optimal process conditions,the effects of various experimental variables,such as reaction temperature,reaction time,catalyst dosage,volume of organic solvent,as well as inorganic salt type on glucose conversion to HMF in three systems were investigated in detail.It was found that under optimal reaction conditions,H2O?THF,H2O?2-butanol and H2O?MeTHF allowed the glucose dehydration process to achieve HMF yields of up to 61%,59%,and 50%,respectively.Moreover,in the three biphasic systems,the H-ZSM-5 catalyst was also demonstrated to maintain excellent stability.Thus,the catalytic approach proposed in this paper can be believed to have potential prospects for industrially efficient and low-cost production of HMF.展开更多
Mulliken, NPA, MK and CHelpG population analyses have been accomplished at the level of MP2/6-31G（d,p） for the title system. The variations of four kinds of charges on NH3 with intermolecular distance infer that ele...Mulliken, NPA, MK and CHelpG population analyses have been accomplished at the level of MP2/6-31G（d,p） for the title system. The variations of four kinds of charges on NH3 with intermolecular distance infer that electron transfers from NH3 to H2O. MK and CHelpG population analyses indicate more electron transfer than Mulliken and NPA ones. The atomic charges resulted from MK and CHelpG schemes infer that electron transfers from N in NH3 to H in H2O, which confirms that this bimolecular complex possesses linear structure as H3N…HOH.展开更多
The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide (EOPO)/salt aqueous two-phase systems at 298.15K. It was found that most of baicalin partitioned into EOPO-rich phase. The par...The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide (EOPO)/salt aqueous two-phase systems at 298.15K. It was found that most of baicalin partitioned into EOPO-rich phase. The partition coefficients of baicalin varied from 10 to 120. The effect of various factors, including tie-line length, salt composition, molecular weight of EOPO, and solution pH, on the partition behavior was investigated in EOPO/salt systems. Furthermore the partition coefficients of baicalin were correlated using the modified Diamond-Hsu model. Good agreement with experimental data is obtained. The average relative deviations are less than 5.0%.展开更多
We present an approximate analytical solution to periodically driven two-level system in the weak-coupling regime. The analytical solution is in good agreement with the exact numerical solution in resonance and near r...We present an approximate analytical solution to periodically driven two-level system in the weak-coupling regime. The analytical solution is in good agreement with the exact numerical solution in resonance and near resonance cases when Ω 〈 0.3ωa with Ω and ωa denoting the Rabi and transition frequencies respectively.展开更多
We analyze the ground-state properties and the excitation spectrum of Bose-Einstein condensates of photons and PPs in a two-dimensional optical microcavity. First, using the variational method, we discuss the ground-s...We analyze the ground-state properties and the excitation spectrum of Bose-Einstein condensates of photons and PPs in a two-dimensional optical microcavity. First, using the variational method, we discuss the ground-state phase transition of the two-component system. We also investigate the energy gap between the ground state and the first excited state. Moreover, by investigating the excitation spectrum, we also illustrate how the superfluid behavior of photons and PPs can be associated with the phase transition of the system.展开更多
基金Project(3207049713)supported by the Scientific Research Foundation of Graduate School of Southeast University,China
文摘With the aim of achieving a high 5-hydroxymethylfurfural(HMF)yield from glucose with H-ZSM-5 catalyst at low cost,three inexpensive biphasic reaction systems,H2O?tetrahydrofuran(THF),H2O?2-methyltetrahydrofuran(MeTHF)and H2O?2-butanol,were discovered and proved to be particularly effective in promoting the formation of HMF from glucose over H-ZSM-5 zeolite.In order to determine the optimal process conditions,the effects of various experimental variables,such as reaction temperature,reaction time,catalyst dosage,volume of organic solvent,as well as inorganic salt type on glucose conversion to HMF in three systems were investigated in detail.It was found that under optimal reaction conditions,H2O?THF,H2O?2-butanol and H2O?MeTHF allowed the glucose dehydration process to achieve HMF yields of up to 61%,59%,and 50%,respectively.Moreover,in the three biphasic systems,the H-ZSM-5 catalyst was also demonstrated to maintain excellent stability.Thus,the catalytic approach proposed in this paper can be believed to have potential prospects for industrially efficient and low-cost production of HMF.
基金the National Science Foundation (29773021) and Provisional Educational Foundation of Jiangsu (98KJB150001).
文摘Mulliken, NPA, MK and CHelpG population analyses have been accomplished at the level of MP2/6-31G（d,p） for the title system. The variations of four kinds of charges on NH3 with intermolecular distance infer that electron transfers from NH3 to H2O. MK and CHelpG population analyses indicate more electron transfer than Mulliken and NPA ones. The atomic charges resulted from MK and CHelpG schemes infer that electron transfers from N in NH3 to H in H2O, which confirms that this bimolecular complex possesses linear structure as H3N…HOH.
基金Supported by the National Natural Science Foundation of China (No. 29736180).
文摘The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide (EOPO)/salt aqueous two-phase systems at 298.15K. It was found that most of baicalin partitioned into EOPO-rich phase. The partition coefficients of baicalin varied from 10 to 120. The effect of various factors, including tie-line length, salt composition, molecular weight of EOPO, and solution pH, on the partition behavior was investigated in EOPO/salt systems. Furthermore the partition coefficients of baicalin were correlated using the modified Diamond-Hsu model. Good agreement with experimental data is obtained. The average relative deviations are less than 5.0%.
基金The project supported by the Postdoctoral Science Foundation of China under Grant Nos.20060408878 and 2007RS4015Key Science Research Foundation of the Education Ministry of China,Natural Science Foundation of Hunan Province of China under Grant No.05JJ40007Key Science Research Foundation of the Education Department of Hunan Province under Grant No.07A057
文摘We present an approximate analytical solution to periodically driven two-level system in the weak-coupling regime. The analytical solution is in good agreement with the exact numerical solution in resonance and near resonance cases when Ω 〈 0.3ωa with Ω and ωa denoting the Rabi and transition frequencies respectively.
文摘We analyze the ground-state properties and the excitation spectrum of Bose-Einstein condensates of photons and PPs in a two-dimensional optical microcavity. First, using the variational method, we discuss the ground-state phase transition of the two-component system. We also investigate the energy gap between the ground state and the first excited state. Moreover, by investigating the excitation spectrum, we also illustrate how the superfluid behavior of photons and PPs can be associated with the phase transition of the system.
