An inverse spinel-type metal oxide, magnesium-manganese-titanium oxide (Mg2Mn0.5Ti0.5O4), were prepared using the coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material ...An inverse spinel-type metal oxide, magnesium-manganese-titanium oxide (Mg2Mn0.5Ti0.5O4), were prepared using the coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material was investigated by X-ray, saturation capacity of exchange, pH titration, and distribution coefficient (Kd) measurement. The acid treatments of Mg2Mn0.5Ti0.5O4 caused Mg^2+ extractions of more than 81%, whereas the dissolutions of Mn^4+ and Ti^4+ were less than 10%. The experimental results proved that the acid-treated sample has a capacity of exchange 56 mg·g^-1 for Li^+ in the solution. The chemical analysis showed that the Li^+ extraction/insertion progressed mainly by ion-exchange mechanism and surface adsorption.展开更多
Rechargeable aqueous zinc ion batteries(AZIBs)were considered as one of the most promising candidates for large-scale energy storage due to the merits of high safety and inexpensiveness.As AZIBs cathode material,Mn O_...Rechargeable aqueous zinc ion batteries(AZIBs)were considered as one of the most promising candidates for large-scale energy storage due to the merits of high safety and inexpensiveness.As AZIBs cathode material,Mn O_(2)possesses great merits but was greatly hindered due to the sluggish diffusion kinetic of Zn^(2+) during electrochemical operations.Herein,deep Zn^(2+) ions intercalatedδ-Mn O_(2)(Zn-Mn O_(2))was achieved by the in situ electrochemical deposition route,which significantly enhanced the diffusion ability of Zn^(2+) due to the synergistic effects of Zn^(2+) pillars and structural H;O.The resultant Zn-Mn O_(2)based AZIBs delivers a record capacity of 696 m Ah/g(0.5 m Ah/cm^(2))based on the initial mass loading,which is approaching the theoretical capacity of Mn O_(2)with a two-electrons reaction.In-situ Raman studies reveal highly reversible Zn^(2+)ions insertion/extraction behaviors and here the Zn-Mn O_(2)plays the role of a container during the charge–discharge process.Further charge storage mechanism investigations point out the insertion/extraction of Zn^(2+) and H^(+) coincides,and such process is significantly facilitated results from superior interlayered configurations of Zn-Mn O_(2)The excellent electrochemical performance of Zn-Mn O_(2)achieved in this work suggests the deep ions pre-intercalation strategy may aid in the future development of advanced cathodes for AZIBs.展开更多
Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of ex...Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materiaIs on electrochemical Li insertion/extraction performance was discussed. These two transition metal oxides belong to onegroup that the crystallinity of these oxides affects to the performance.展开更多
Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and...Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction pedermance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not; LiMn_2O_4 and LiCo_(0.5)O_2 belongs to the former group and TiO_2, V_2O_5 and MoO_3 to the latter.展开更多
The work distills the main mechanisms during the lithium insertion/extraction of LiFePOcathode materials. The "diffusion-controlled" and "phase-boundary controlled" mechanism are especially illustr...The work distills the main mechanisms during the lithium insertion/extraction of LiFePOcathode materials. The "diffusion-controlled" and "phase-boundary controlled" mechanism are especially illustrated. Meanwhile, some recent observation and analyses by in-situ or in operando on the Li-insertion/extraction of LiFePOare summarized and prospected.展开更多
The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal an...The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal analysis,X-ray diffraction spectroscopy,scanning electron microscopy,and energy dispersive spectrometry were used to characterize the solid-state reaction of the samples.The extent of the solid reac-tion was derived using the preliminary quantitative phase analysis of the X-ray patterns.The results indicate that the solid reaction of the CaO−V_(2)O_(5)mixture is strongly influenced by the reaction temperature and CaO/V_(2)O_(5)mole ratio.The transformation of calcium vanadate in-volves a step-by-step reaction of CaO−V_(2)O_(5),CaO−CaV_(2)O_(6),and CaO−Ca_(2)V_(2)O7 depending on the CaO/V_(2)O_(5)mole ratio.The kinetic data of the solid reaction of the CaO−V_(2)O_(5)(1:1)mixture followed a second-order reaction model.The activation energy(Ea)and preexponential factor(A)were determined to be 145.38 kJ/mol,and 3.67×10^(8)min^(−1),respectively.展开更多
Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigate...Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. Meanwhile, the effects of various factors on the formation of soluble potassium and phosphate were also discussed. The reaction products and residues were determined by X-ray diffraction(XRD), scanning electron microscopic(SEM) analysis and other means. The results showed that the dissolution rates of potassium and phosphorus were 70wt% and 93.7wt%, respectively, under the conditions of a grain size of 95.64wt% lessthan 0.074 mm, 9.78 g·g^(-1) sulfuric acid, 0.5 g·g^(-1) ammonium fluoride, 160 ℃ and a reaction time of 2h. The thermodynamic and chemical reaction mechanism was revealed that the primary reaction could be completed spontaneously in a temperature range of 298-433 K. The increase of reaction temperature had an important influence on ion exchange reaction, which was more conducive to the spontaneous process. The research will open up a new way for efficient use of potassium ore resources.展开更多
The insertion reactions of germylene into C-Cl bond of 1-chorobenzene have been explored using density functional theory. Five germylene species have been chosen for systematically studying. All the stationary points ...The insertion reactions of germylene into C-Cl bond of 1-chorobenzene have been explored using density functional theory. Five germylene species have been chosen for systematically studying. All the stationary points were determined at the B3LYP/ 6-311+G (d, p) level of the theory. The results show that, the smaller the AEsT of germylene, the lower the barrier height, and the electropositive substituents on the germylene can increase the reaction activity and exothermicity of insertion into C-Cl bond of 1- chorobenzene.展开更多
Theoretical investigations on the insertion reaction mechanisms of three- membered-ring silylenoid H2 Si Li F with GeH 3R(R = F, OH, NH2) have been systematically carried out by combined density functional theory(...Theoretical investigations on the insertion reaction mechanisms of three- membered-ring silylenoid H2 Si Li F with GeH 3R(R = F, OH, NH2) have been systematically carried out by combined density functional theory(DFT) and ab initio quantum chemical calculations. The geometries of all stationary points for these reactions were optimized using the B3 LYP method and then the QCISD method was used to calculate the single-point energies. The calculated results indicate that, there are one precursor complex(Q), one transition state(TS), and one intermediate(IM) which connect the reactants and the products along the potential energy surface. The insertion reactions of three-membered-ring silylenoid with Ge H3 R proceed in a concerted manner, forming H2RSi-Ge H3 and Li F. The calculated potential energy barriers of the three reactions are 29.17, 30.90, and 54.07 k J/mol, and the reaction energies for the three reactions are –127.05, –116.91, and –103.31 k J/mol, respectively. The insertion reactions in solvents are similar to those in vacuum. Under the same situation, the insertion reactions should occur easily in the following order: GeH 3-F GeH 3-OH GeH 3-NH2. The elucidations of the mechanism of these insertion reactions provided a new mode of silicon-germanium bond formation.展开更多
The basic method of DNA extraction (CTAB) was improved as the multi-times STE-CTAB extraction method and used to extract the DNA of birch leaved in this experiment. Results showed that the improved method is suitabl...The basic method of DNA extraction (CTAB) was improved as the multi-times STE-CTAB extraction method and used to extract the DNA of birch leaved in this experiment. Results showed that the improved method is suitable not only for genomic DNA extraction of birch but also for that of other plants. The purity of genornic DNA extracted by the.multi-times STE-CTAB extraction method is higher than that by one time STE-CTAB method, and it does not need the process of RNase. The factors of influencing ISSR system were explored based on the genomic DNA of birch extracted by the two methods. The optimal conditions for ISSR system were determined as follows: Mg2+ concentration is 1.5-3.0 mmol·L^-1, dNTP concentration 0.104).25 mmol·L^-1, the quantity of Taq polymerase 0.5-2.0 U, template DNA 30-100 ng, and the concentration of primer is 0.2-0.4 pmmol·L^-1, and the reaction program was as: initial denaturation for 5 min at 94℃, 30 cycles of denaturation for 30 s at 94℃,annealing for 30 s at 51℃, extension for 30 s at 72℃, and a final 7 min extension at 72℃.展开更多
The kinetics of forward extraction of Ti(IV) from H2SO4 medium by P507 in kerosene has been investigated using the single drop technique.In the low concentration region of Ti(IV),the rate of forward extraction at ...The kinetics of forward extraction of Ti(IV) from H2SO4 medium by P507 in kerosene has been investigated using the single drop technique.In the low concentration region of Ti(IV),the rate of forward extraction at 298 K can be represented by F(kmol·m-2·s-1)=10-5.07 [TiO 2 + ][H+]-1 [NaHA 2 ](o)·Analysis of the rate expression reveals that the rate determining step is(TiO)(i)2+ +(HA 2)(i)-[TiO(HA2)](i)+.The values of Ea,H±,S±,and G±298 are calculated to be 22 kJ·mol-1,25 kJ·mol-1,-218 J·mol-1·K-1,and 25 kJ·mol-1,respectively.The experimental negative S± values indicate that the reaction step occurs via SN2 mechanism.展开更多
Our over dependency on the fossil resource for industrial chemicals and fuels faces great challenges. Recently, the production of monophenols from lignin in lignocellulosic biomass is regarded as a promising process f...Our over dependency on the fossil resource for industrial chemicals and fuels faces great challenges. Recently, the production of monophenols from lignin in lignocellulosic biomass is regarded as a promising process for sustainable biofuels. This article discusses the conversion of lignin in actual biomass directly to monophenols. The two step way including extraction of lignin from biomass and further degradation of the lignin oligomers to monophenols is especially discussed. The obtained monophenols can also be converted to chemicals with low-oxygen content via hydrodeoxygenation process. For extraction of lignin, co-solvent system is the most adopted for hydrolysis or solvolysis of lignin assisted by acid or alkaline catalysts. The structure of the obtained oligomers derived from lignin is discussed in detail. For lignin depolymerization, hydrogenolysis is an efficient method with the use of gaseous hydrogen or alcohols as hydrogen source. At the meantime, depolymerization mechanism and the route for repolymerization of the reaction intermediates are presented here. In hydrodeoxygenation process, metal catalysts, especially noble metal catalysts are required. The precise effects of the reaction solvents and catalysts on extraction and degradation of lignin need to be further investigated, and this will benefit to design more efficient strategies for lignin utilization. ? 2016 Science Press展开更多
The solvent extraction of La 3+ from hydrochloric acid solutions was investigated using bis (2, 4, 4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HL) as an extractant. The effect of equilibrium of aqueous ac...The solvent extraction of La 3+ from hydrochloric acid solutions was investigated using bis (2, 4, 4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HL) as an extractant. The effect of equilibrium of aqueous acidity on extraction of La 3+ using Cyanex 302 in different diluents was discussed. The effects of extractant concentration and chloride ion on the extraction reaction were also studied. Stoichiometry of the extraction reactions and the nature of metal complexes formed were determined using slope analysis technique and IR measurement.展开更多
NH4HCO3 conversion followed by HCl leaching was performed and proven to be effective in extracting Pb and Sr from zinc extracted residual.The mechanism and operating conditions of NH4HCO3 conversion,including molar ra...NH4HCO3 conversion followed by HCl leaching was performed and proven to be effective in extracting Pb and Sr from zinc extracted residual.The mechanism and operating conditions of NH4HCO3 conversion,including molar ratio of NH4HCO3 to zinc extracted residual,NH4HCO3 concentration,conversion temperature,conversion time,and stirring velocity,were discussed,and operating conditions were optimized by the orthogonal test.Experimental results indicate that NH4HCO3 conversion at temperatures ranging from 25 to 85°C follows the shrinking unreacted core model and is controlled by inner diffusion through the product layer.The extraction ratios of Pb and Sr under optimized conditions reached 85.15%and 87.08%,respectively.Moreover,the apparent activation energies of Pb and Sr were 13.85 and 13.67 kJ·mol^−1,respectively.展开更多
Selenium was inserted into the zinc carbon bond of aryl zinc halides to form corresponding zinc selenoates. They reacted in THF-HMPA with acylhalides to afford the selenoesters in high yields.
The extraction of lithium from salt lake brine in the Chinese Qaidam Basin is challenging due to its high Mg/Li and Na/Li ratios. Herein, we utilized a reaction-coupled separation technology to separate sodium and lit...The extraction of lithium from salt lake brine in the Chinese Qaidam Basin is challenging due to its high Mg/Li and Na/Li ratios. Herein, we utilized a reaction-coupled separation technology to separate sodium and lithium ions from a high Na/Li ratio brine(Na/Li = 48.7, w/w) and extracted lithium with Li Al-layered double hydroxides(Li Al-LDHs). The Li Al-LDHs act as lithium-ion-selective capturing materials from multication brines. That is, the lithium ions selectively enter the solid phase to form Li Al-LDHs, and the sodium ions are still retained in the liquid phase. This is because the lithium ions can be incorporated into the structural vacancies of LiAl-LDHs, whereas the sodium ions cannot. The effects of reaction conditions on lithium loss and separation efficiency were investigated at both the nucleation and the crystallization stage, e.g., the nucleation rotating speed, the Li/Al molar ratio, the crystallization temperature and time, and co-existing cations. The lithium loss is as low as 3.93% under optimal separation conditions.The sodium ions remained in the solution. Consequently, an excellent Na/Li separation efficiency was achieved by this reaction-coupled separation technology. These findings confirm that LiAl-LDHs play a critical function in selectively capturing lithium ions from brines with a high Na/Li ratio, which is useful for the extraction of lithium ions from the abundant salt lake brine resources in China.展开更多
One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.
The extractive reaction process of oxygen-working solution-water three-phase system for the production of hydrogen peroxide by the anthraquinone method was investigated in a sieve plate column of 50 mm in internal dia...The extractive reaction process of oxygen-working solution-water three-phase system for the production of hydrogen peroxide by the anthraquinone method was investigated in a sieve plate column of 50 mm in internal diameter. The oxidation reaction of anthrahydroquinone in the working solution with oxygen and the extraction of hydrogen peroxide from the working solution into aqueous phase occurred simultaneously in the countercurrent mode. The agitating effect caused by gaseous phase made the droplets of the dispersed phase become smaller, thus, increasing the liquid-liquid interfacial contact areas and resulting in the improvement of the mass transfer velocity. Results showed that the gas-agitation had a beneficial effect on the extraction of hydrogen peroxide from the working solution into the aqueous phase; the concentration of hydrogen peroxide in the raffinate decreased with the increase of the gaseous superficial velocities; and the concentration of H2O2 in the raffinate increased with the increase of the dispersed phase superficial velocity at the same superficial velocity of the gaseous phase. In the G-L-L extractive reaction process, with the increase of the gaseous superficial velocities, both the conversion of the anthrahydroquinone oxidation and the extraction efficiency of hydrogen peroxide first increased significantly, then increased gradually.展开更多
Dynamic interfacial properties are investigated for solvent extraction systems of metals by organophosphoric or phosphonic acid. The relationship between interfacial properties and kinetic parameters shows that the dy...Dynamic interfacial properties are investigated for solvent extraction systems of metals by organophosphoric or phosphonic acid. The relationship between interfacial properties and kinetic parameters shows that the dynamic interfacial properties are important to mass transfer processes in liquid-liquid extraction. The authors develop a two-film adsorption model which may offer a basis for researching interfacial activity in mass transfer processes.展开更多
文摘An inverse spinel-type metal oxide, magnesium-manganese-titanium oxide (Mg2Mn0.5Ti0.5O4), were prepared using the coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material was investigated by X-ray, saturation capacity of exchange, pH titration, and distribution coefficient (Kd) measurement. The acid treatments of Mg2Mn0.5Ti0.5O4 caused Mg^2+ extractions of more than 81%, whereas the dissolutions of Mn^4+ and Ti^4+ were less than 10%. The experimental results proved that the acid-treated sample has a capacity of exchange 56 mg·g^-1 for Li^+ in the solution. The chemical analysis showed that the Li^+ extraction/insertion progressed mainly by ion-exchange mechanism and surface adsorption.
基金financially supported by the National Natural Science Foundation of China(Nos.51772138,51572118,and 51601082)the Fundamental Research Funds for the Central Universities(No.lzujbky-2020-59)。
文摘Rechargeable aqueous zinc ion batteries(AZIBs)were considered as one of the most promising candidates for large-scale energy storage due to the merits of high safety and inexpensiveness.As AZIBs cathode material,Mn O_(2)possesses great merits but was greatly hindered due to the sluggish diffusion kinetic of Zn^(2+) during electrochemical operations.Herein,deep Zn^(2+) ions intercalatedδ-Mn O_(2)(Zn-Mn O_(2))was achieved by the in situ electrochemical deposition route,which significantly enhanced the diffusion ability of Zn^(2+) due to the synergistic effects of Zn^(2+) pillars and structural H;O.The resultant Zn-Mn O_(2)based AZIBs delivers a record capacity of 696 m Ah/g(0.5 m Ah/cm^(2))based on the initial mass loading,which is approaching the theoretical capacity of Mn O_(2)with a two-electrons reaction.In-situ Raman studies reveal highly reversible Zn^(2+)ions insertion/extraction behaviors and here the Zn-Mn O_(2)plays the role of a container during the charge–discharge process.Further charge storage mechanism investigations point out the insertion/extraction of Zn^(2+) and H^(+) coincides,and such process is significantly facilitated results from superior interlayered configurations of Zn-Mn O_(2)The excellent electrochemical performance of Zn-Mn O_(2)achieved in this work suggests the deep ions pre-intercalation strategy may aid in the future development of advanced cathodes for AZIBs.
文摘Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materiaIs on electrochemical Li insertion/extraction performance was discussed. These two transition metal oxides belong to onegroup that the crystallinity of these oxides affects to the performance.
文摘Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction pedermance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not; LiMn_2O_4 and LiCo_(0.5)O_2 belongs to the former group and TiO_2, V_2O_5 and MoO_3 to the latter.
基金supported by the National Natural Science Foundation of China(No.51504196)Key Research and Development Plan of Shaanxi Province(No.2017ZDXM-GY-039)
文摘The work distills the main mechanisms during the lithium insertion/extraction of LiFePOcathode materials. The "diffusion-controlled" and "phase-boundary controlled" mechanism are especially illustrated. Meanwhile, some recent observation and analyses by in-situ or in operando on the Li-insertion/extraction of LiFePOare summarized and prospected.
基金This work was financially supported by the National Natural Science Foundation of China(No.52004044)the Natural Science Foundation of Chongqing,China(No.cstc2019jcyj-bshX0068)Chongqing Postdoctoral Innovation Program(No.CQBX201904),and the Open Project Founded by the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization.
文摘The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery process.Thermal analysis,X-ray diffraction spectroscopy,scanning electron microscopy,and energy dispersive spectrometry were used to characterize the solid-state reaction of the samples.The extent of the solid reac-tion was derived using the preliminary quantitative phase analysis of the X-ray patterns.The results indicate that the solid reaction of the CaO−V_(2)O_(5)mixture is strongly influenced by the reaction temperature and CaO/V_(2)O_(5)mole ratio.The transformation of calcium vanadate in-volves a step-by-step reaction of CaO−V_(2)O_(5),CaO−CaV_(2)O_(6),and CaO−Ca_(2)V_(2)O7 depending on the CaO/V_(2)O_(5)mole ratio.The kinetic data of the solid reaction of the CaO−V_(2)O_(5)(1:1)mixture followed a second-order reaction model.The activation energy(Ea)and preexponential factor(A)were determined to be 145.38 kJ/mol,and 3.67×10^(8)min^(−1),respectively.
基金Funded by the National Natural Science Fundation of China(51274158)the National Twelfth Five-Year Plan for Scientific and Technological Support(2013BAE04B03)the Scientific and Technological Support Project of Hubei Province(2015BCA251)
文摘Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. Meanwhile, the effects of various factors on the formation of soluble potassium and phosphate were also discussed. The reaction products and residues were determined by X-ray diffraction(XRD), scanning electron microscopic(SEM) analysis and other means. The results showed that the dissolution rates of potassium and phosphorus were 70wt% and 93.7wt%, respectively, under the conditions of a grain size of 95.64wt% lessthan 0.074 mm, 9.78 g·g^(-1) sulfuric acid, 0.5 g·g^(-1) ammonium fluoride, 160 ℃ and a reaction time of 2h. The thermodynamic and chemical reaction mechanism was revealed that the primary reaction could be completed spontaneously in a temperature range of 298-433 K. The increase of reaction temperature had an important influence on ion exchange reaction, which was more conducive to the spontaneous process. The research will open up a new way for efficient use of potassium ore resources.
基金the Natural Science Foundation of Shandong Province(No.Y2006B420) for financial support for this work.
文摘The insertion reactions of germylene into C-Cl bond of 1-chorobenzene have been explored using density functional theory. Five germylene species have been chosen for systematically studying. All the stationary points were determined at the B3LYP/ 6-311+G (d, p) level of the theory. The results show that, the smaller the AEsT of germylene, the lower the barrier height, and the electropositive substituents on the germylene can increase the reaction activity and exothermicity of insertion into C-Cl bond of 1- chorobenzene.
基金supported by the National Natural Science Foundation Committee of China(No.21103145)the Natural Science Foundation of Shandong Province(No.ZR2009BQ006)+3 种基金the Fund for Doctor of Yantai University(No.HY05B30)the Special Foundation of Youth Academic Backbone of Yantai Universitysupport by the Open fund(sklssm201418)of the State Key Laboratory of Supramolecular Structure and Materials,Jilin Universitythe Graduate Innovation Foundation of Yantai University,GIFYTU
文摘Theoretical investigations on the insertion reaction mechanisms of three- membered-ring silylenoid H2 Si Li F with GeH 3R(R = F, OH, NH2) have been systematically carried out by combined density functional theory(DFT) and ab initio quantum chemical calculations. The geometries of all stationary points for these reactions were optimized using the B3 LYP method and then the QCISD method was used to calculate the single-point energies. The calculated results indicate that, there are one precursor complex(Q), one transition state(TS), and one intermediate(IM) which connect the reactants and the products along the potential energy surface. The insertion reactions of three-membered-ring silylenoid with Ge H3 R proceed in a concerted manner, forming H2RSi-Ge H3 and Li F. The calculated potential energy barriers of the three reactions are 29.17, 30.90, and 54.07 k J/mol, and the reaction energies for the three reactions are –127.05, –116.91, and –103.31 k J/mol, respectively. The insertion reactions in solvents are similar to those in vacuum. Under the same situation, the insertion reactions should occur easily in the following order: GeH 3-F GeH 3-OH GeH 3-NH2. The elucidations of the mechanism of these insertion reactions provided a new mode of silicon-germanium bond formation.
基金This paper was supported by National Natural Science Foundation of China (No. 30571513) and National High Technology Research and Development Program of China (863 Program) (No. 2002AA241080).
文摘The basic method of DNA extraction (CTAB) was improved as the multi-times STE-CTAB extraction method and used to extract the DNA of birch leaved in this experiment. Results showed that the improved method is suitable not only for genomic DNA extraction of birch but also for that of other plants. The purity of genornic DNA extracted by the.multi-times STE-CTAB extraction method is higher than that by one time STE-CTAB method, and it does not need the process of RNase. The factors of influencing ISSR system were explored based on the genomic DNA of birch extracted by the two methods. The optimal conditions for ISSR system were determined as follows: Mg2+ concentration is 1.5-3.0 mmol·L^-1, dNTP concentration 0.104).25 mmol·L^-1, the quantity of Taq polymerase 0.5-2.0 U, template DNA 30-100 ng, and the concentration of primer is 0.2-0.4 pmmol·L^-1, and the reaction program was as: initial denaturation for 5 min at 94℃, 30 cycles of denaturation for 30 s at 94℃,annealing for 30 s at 51℃, extension for 30 s at 72℃, and a final 7 min extension at 72℃.
基金supported by the Key Subject of Shanghai Municipality (S30109)the Opening Project of Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST),the Ministry of Education (09zxgk02)Research Program of Science and Technology Commission of Shanghai Municipality (09dz1204403)
文摘The kinetics of forward extraction of Ti(IV) from H2SO4 medium by P507 in kerosene has been investigated using the single drop technique.In the low concentration region of Ti(IV),the rate of forward extraction at 298 K can be represented by F(kmol·m-2·s-1)=10-5.07 [TiO 2 + ][H+]-1 [NaHA 2 ](o)·Analysis of the rate expression reveals that the rate determining step is(TiO)(i)2+ +(HA 2)(i)-[TiO(HA2)](i)+.The values of Ea,H±,S±,and G±298 are calculated to be 22 kJ·mol-1,25 kJ·mol-1,-218 J·mol-1·K-1,and 25 kJ·mol-1,respectively.The experimental negative S± values indicate that the reaction step occurs via SN2 mechanism.
基金financially supported by the National Natural Science Foundation of China (No.21536007)
文摘Our over dependency on the fossil resource for industrial chemicals and fuels faces great challenges. Recently, the production of monophenols from lignin in lignocellulosic biomass is regarded as a promising process for sustainable biofuels. This article discusses the conversion of lignin in actual biomass directly to monophenols. The two step way including extraction of lignin from biomass and further degradation of the lignin oligomers to monophenols is especially discussed. The obtained monophenols can also be converted to chemicals with low-oxygen content via hydrodeoxygenation process. For extraction of lignin, co-solvent system is the most adopted for hydrolysis or solvolysis of lignin assisted by acid or alkaline catalysts. The structure of the obtained oligomers derived from lignin is discussed in detail. For lignin depolymerization, hydrogenolysis is an efficient method with the use of gaseous hydrogen or alcohols as hydrogen source. At the meantime, depolymerization mechanism and the route for repolymerization of the reaction intermediates are presented here. In hydrodeoxygenation process, metal catalysts, especially noble metal catalysts are required. The precise effects of the reaction solvents and catalysts on extraction and degradation of lignin need to be further investigated, and this will benefit to design more efficient strategies for lignin utilization. ? 2016 Science Press
文摘The solvent extraction of La 3+ from hydrochloric acid solutions was investigated using bis (2, 4, 4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HL) as an extractant. The effect of equilibrium of aqueous acidity on extraction of La 3+ using Cyanex 302 in different diluents was discussed. The effects of extractant concentration and chloride ion on the extraction reaction were also studied. Stoichiometry of the extraction reactions and the nature of metal complexes formed were determined using slope analysis technique and IR measurement.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51774070,52004165,and 51574084).
文摘NH4HCO3 conversion followed by HCl leaching was performed and proven to be effective in extracting Pb and Sr from zinc extracted residual.The mechanism and operating conditions of NH4HCO3 conversion,including molar ratio of NH4HCO3 to zinc extracted residual,NH4HCO3 concentration,conversion temperature,conversion time,and stirring velocity,were discussed,and operating conditions were optimized by the orthogonal test.Experimental results indicate that NH4HCO3 conversion at temperatures ranging from 25 to 85°C follows the shrinking unreacted core model and is controlled by inner diffusion through the product layer.The extraction ratios of Pb and Sr under optimized conditions reached 85.15%and 87.08%,respectively.Moreover,the apparent activation energies of Pb and Sr were 13.85 and 13.67 kJ·mol^−1,respectively.
文摘Selenium was inserted into the zinc carbon bond of aryl zinc halides to form corresponding zinc selenoates. They reacted in THF-HMPA with acylhalides to afford the selenoesters in high yields.
基金supported by the National Natural Science Foundation of China (Grant U1507202, U1707603)the Innovative Research Groups of National Natural Science Foundation of China (Grant 21521005)the Key R&D Program of Qinghai Province (Grant 2017-GX-144)
文摘The extraction of lithium from salt lake brine in the Chinese Qaidam Basin is challenging due to its high Mg/Li and Na/Li ratios. Herein, we utilized a reaction-coupled separation technology to separate sodium and lithium ions from a high Na/Li ratio brine(Na/Li = 48.7, w/w) and extracted lithium with Li Al-layered double hydroxides(Li Al-LDHs). The Li Al-LDHs act as lithium-ion-selective capturing materials from multication brines. That is, the lithium ions selectively enter the solid phase to form Li Al-LDHs, and the sodium ions are still retained in the liquid phase. This is because the lithium ions can be incorporated into the structural vacancies of LiAl-LDHs, whereas the sodium ions cannot. The effects of reaction conditions on lithium loss and separation efficiency were investigated at both the nucleation and the crystallization stage, e.g., the nucleation rotating speed, the Li/Al molar ratio, the crystallization temperature and time, and co-existing cations. The lithium loss is as low as 3.93% under optimal separation conditions.The sodium ions remained in the solution. Consequently, an excellent Na/Li separation efficiency was achieved by this reaction-coupled separation technology. These findings confirm that LiAl-LDHs play a critical function in selectively capturing lithium ions from brines with a high Na/Li ratio, which is useful for the extraction of lithium ions from the abundant salt lake brine resources in China.
基金We are grateful to the National Natural Science Foundation of China (Nos. 20332060 and 2472072)
文摘One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.
基金Supported by State Key Fundamental Research Project of China(No.G20004085) and National Natural Science Foundationof China(No.C20106011).
文摘The extractive reaction process of oxygen-working solution-water three-phase system for the production of hydrogen peroxide by the anthraquinone method was investigated in a sieve plate column of 50 mm in internal diameter. The oxidation reaction of anthrahydroquinone in the working solution with oxygen and the extraction of hydrogen peroxide from the working solution into aqueous phase occurred simultaneously in the countercurrent mode. The agitating effect caused by gaseous phase made the droplets of the dispersed phase become smaller, thus, increasing the liquid-liquid interfacial contact areas and resulting in the improvement of the mass transfer velocity. Results showed that the gas-agitation had a beneficial effect on the extraction of hydrogen peroxide from the working solution into the aqueous phase; the concentration of hydrogen peroxide in the raffinate decreased with the increase of the gaseous superficial velocities; and the concentration of H2O2 in the raffinate increased with the increase of the dispersed phase superficial velocity at the same superficial velocity of the gaseous phase. In the G-L-L extractive reaction process, with the increase of the gaseous superficial velocities, both the conversion of the anthrahydroquinone oxidation and the extraction efficiency of hydrogen peroxide first increased significantly, then increased gradually.
文摘Dynamic interfacial properties are investigated for solvent extraction systems of metals by organophosphoric or phosphonic acid. The relationship between interfacial properties and kinetic parameters shows that the dynamic interfacial properties are important to mass transfer processes in liquid-liquid extraction. The authors develop a two-film adsorption model which may offer a basis for researching interfacial activity in mass transfer processes.