Al/TiO_(2) self-combustion synthesis reaction has been studied,including the effect of initial conditions of reactants on combustion temperature,combustion velocity and combustion stability etc.The reaction mechanism ...Al/TiO_(2) self-combustion synthesis reaction has been studied,including the effect of initial conditions of reactants on combustion temperature,combustion velocity and combustion stability etc.The reaction mechanism of Al/TiO_(2) self-combustion synthesis has been studied emphatically and the dynamic reaction model has been created.展开更多
Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in...Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mgPt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst （0.20 A/mgPt）. Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.展开更多
A novel in-situ process-Reaction Synthesis has been used to fabricate Al/TiC compos-ites,the phase constitute,microstructure and mechanical property of the Al/TiC composite have been investigated by the use of XRD and...A novel in-situ process-Reaction Synthesis has been used to fabricate Al/TiC compos-ites,the phase constitute,microstructure and mechanical property of the Al/TiC composite have been investigated by the use of XRD and SEM.It has been shown that the reaction synthesized TiC particu-late is submicron in size(about 0.1~0.8μpm),spherical in shape and smooth in surface.In macrostruc-ture the distribution of the TiC particulate in matrix is homogeneous,but in micostructure there is micro-segregation of the TiC particulate at the intergrannular.The cast structure become fine because of the existence of the TiC particulate.In addition«with the increasing of weight percentage of TiC partic-ulate in alloy,the yield strength and ultimate tensile strength of the composite increase significantly«e.g.at 15%TiC,117% and 103% increase respectively,in the same time the elongation of the composite is still more than 4.5%.In the end,the analysis has been done by SEM on the fracture morphology of the composite.The results show that the fracture is ductility,and mainly because of the cluster of TiC particulate to intergrannular and the synthesis of bar morphology Al_(3)Ti.展开更多
The reaction mechanism of glyoxal （G） with urea （U） under weak acid condition was theoretically investigated at PW91/DNP/COSMO of quantum chemistry using density functional theory （DFT） method. The results show ...The reaction mechanism of glyoxal （G） with urea （U） under weak acid condition was theoretically investigated at PW91/DNP/COSMO of quantum chemistry using density functional theory （DFT） method. The results show that the addition reaction of G with U under the conditions mainly involves the reactions of U with protonated glyoxal （p-G）, protonated 2,2-dihy- droxyacetaldehyde （p-G 1） and protonated bis-hemdiol （p-G2） to form two important carbocation reactive intermediates of C-p-UG and C-p-UG1, and two important hydroxyl compounds of UG and UG1. These compounds play important roles in the formation of UG resin. According to the result of quantum chemical calculation, UG resin was synthesized successfully under weak acid conditions. The UG resin was characterized by matrix assisted laser desorption ionization time of flight mass spectrometry （MALDI-TOF-MS）, ultraviolet and visible spectroscopy （UV-vis）, Fourier transform infrared spectroscopy （FT1R） and nuclear magnetic resonance spectroscopy （13CNMR and 1HNMR）. These instrumental analytical results agree with each other and further confirm the addition reaction pathway of glyoxal with urea proposed by quantum chemical calculation.展开更多
The reaction of two series of 2,3-dihydro-1,5-henzothiazepines Ⅰ with dichloro- carbene,gave azirino[2,1-d][1,5]benzothiazepines Ⅷ,azirino[2,1-e][1,6]benzothiazocines Ⅸ, pyrrolo[2,1-b][1,3]benzothiazoles Ⅹ,substit...The reaction of two series of 2,3-dihydro-1,5-henzothiazepines Ⅰ with dichloro- carbene,gave azirino[2,1-d][1,5]benzothiazepines Ⅷ,azirino[2,1-e][1,6]benzothiazocines Ⅸ, pyrrolo[2,1-b][1,3]benzothiazoles Ⅹ,substituted-cyclopropanes Ⅺ and 2H-1,4-benzothiazin-2-ones Ⅻ.The structures of these products were confirmed by the analytical and spectral data.Compound Ⅷ and Ⅸ are two new ring systems.展开更多
Proton NMR-spectra of Wang resin bound compounds were obtained using the magic angle spinning 1HNMR technique with standard equipment. It was possible to analyse the spectra to evaluate their utility in solid-phase ch...Proton NMR-spectra of Wang resin bound compounds were obtained using the magic angle spinning 1HNMR technique with standard equipment. It was possible to analyse the spectra to evaluate their utility in solid-phase chernistry. A typical example was presented, which could directly monitor solid-phase reactions展开更多
The acetalization of a series of carbonyl compounds with ethanediolwas performed over two self-steaxned HY zeolle catalpsts' The acetal and ketaiproducts were obtained with high ytelds Espectw, the HY zeollte with...The acetalization of a series of carbonyl compounds with ethanediolwas performed over two self-steaxned HY zeolle catalpsts' The acetal and ketaiproducts were obtained with high ytelds Espectw, the HY zeollte with highfraxnework Si/A1 ratio was proven to be suitable cataipst for the acetabotion ofunsaturated carbonyl compounds, during which the C =C double bond was notperturbed展开更多
Three kinds of products have been separated from the reaction mixtures of 1,2-dihydro-2, 4-disubstituted-1,5-benzodiazepine with: CCI_2.Besides the addition products of: CCI_2 to C=N.the inserted products of: CCI_2 to...Three kinds of products have been separated from the reaction mixtures of 1,2-dihydro-2, 4-disubstituted-1,5-benzodiazepine with: CCI_2.Besides the addition products of: CCI_2 to C=N.the inserted products of: CCI_2 to N-H and C-H single bonds were obtained, too.展开更多
Direct reaction synthesis(DRS), based on the principle of self-propagating hightemperature synthesis (SHS), is a new method for preparing particulate metal matrix composites (PMMCs). The effects of the temperature of ...Direct reaction synthesis(DRS), based on the principle of self-propagating hightemperature synthesis (SHS), is a new method for preparing particulate metal matrix composites (PMMCs). The effects of the temperature of the aluminum melt and the aluminum content in the preform on the phases and structure of the reacted preform have been investigated by X-ray diffraction and scanning electron microscopy.It has been shown that TiC phase is prone to be synthesized with the increasing of the temperature of the aluminum melt and the decreasing of the aluminum powder content in the preform, and that the size of TiC particle becomes fine with the increasing of the temperature and the decreasing of the aluminum powder content.展开更多
Asymmetric syntheses of both enantiomerically pure (+) and (-) 5-oxo-endo-tricyclo [5.2.1.0.^(2,6)] deca-3, 8-diene 1 was described. The key step is the use of enzyme-catalyzed hydrolysis of meso-diacetate 5.
Dihydro-1-benzoyl-1,5-benzodiazepines react with (ethoxycarbonyl)carbenes to give 4H-azirino-[1,2-a][1,5]-benzodiazepines and unexpected new tin9 system 1H-pyrrolo-[1,2-a][1,5]-benzodiazepines. Dihydro-1,5-benzothiaze...Dihydro-1-benzoyl-1,5-benzodiazepines react with (ethoxycarbonyl)carbenes to give 4H-azirino-[1,2-a][1,5]-benzodiazepines and unexpected new tin9 system 1H-pyrrolo-[1,2-a][1,5]-benzodiazepines. Dihydro-1,5-benzothiazepines react with (ethoxycarbonyl)carbenes in cyclohexane to gire unexpected rin9 cleavage products ethyl (2E, 4E)-3-aryl-2-arylthiohexadienoates.展开更多
As models of 5, 10-methenyl-tetrahydrofolate coenaymes imidazolinium salts 6a. b were synthesized and their carbon transfer reactions with several types of nucleophiles were studied.
Three N,N-heterylmethyl derivates of diaza-18-crown-6(I) are readily prepared by the reaction of (I) with paraformaldehyde and heterocyclic compounds in dry benzene.
Some telluronium salts react easily with 1,4-bis(3-substituted phenyl-3-oxo-1-propenyl)benzene and 1,5-disubstituted phenyl-1,4-pentadien-3 -one to afford derivatives of biscyclopropanes in 61.8-88.8% yield.
The 1.3-dipolar cycloaddition reaction of 2-trifluoromethyl- oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.
CaZrO3 powder was prepared using CaO,CaCO3 and Ca(OH)2 as calcium source,nano m-ZrO2 powder,micron m-ZrO2 powder,micron CaO partially stabilized ZrO2(Ca-PSZ)powder as zircon source,through high temperature solid react...CaZrO3 powder was prepared using CaO,CaCO3 and Ca(OH)2 as calcium source,nano m-ZrO2 powder,micron m-ZrO2 powder,micron CaO partially stabilized ZrO2(Ca-PSZ)powder as zircon source,through high temperature solid reaction.Effect of the calcination temperature(800,900,1000,1100,1200,1300,1400,1500,and 1600℃)and the holding time(3,4,and 5 h)on the phase composition change was studied to research the synthesis mechanism.The synthesized CaZrO3 powder was mixed with CaO,MgO,Al2O3,Cr2O3,SiO2,and ZrO2 powder separately and fired at 1500℃for 3 h to prepare specimens to research the high temperature chemical stability of CaZrO3 with different reaction mediums.The results show that during the synthesis process,the CaZrO3 content does not always increase with the increasing calcination temperature or the prolonging holding time,CaZrO3 decomposes resulting from the diffusion of Ca2+and O2-in CaZrO3 to m-ZrO2 or c-ZrO2.At high temperatures,when CaZrO3 is in alkaline environment(such as environment containing CaO or MgO),the high temperature chemical stability is high,but when CaZrO3 is not in alkaline environment(such as environment containing Al2O3,Cr2O3,SiO2 or ZrO2),the high temperature chemical stability is low.展开更多
The in situ synthesis method for titanium matrix composites （TMCs） has obvious technical and economical advantages over other traditional methods. Ultrafine reinforcement particles were formed in situ by chemical re...The in situ synthesis method for titanium matrix composites （TMCs） has obvious technical and economical advantages over other traditional methods. Ultrafine reinforcement particles were formed in situ by chemical reaction between elements or between elements and compounds. Using the approach, contamination at the composite matrix/reinforcement particle interface did not occur, interface bonding was good, and the reinforcement particle was thermodynamically stable. The stage of development of the preparation process for in situ TMCs as well as the thermodynamic analysis of the possible in situ reaction systems was described.展开更多
The catalytic performance of co mmonly used heteropolyacids （H3PW12O40, H4SiW12O40 and H3PMO12O40 synthesis of 4,4＇-methylenedianiline （4,4＇-MDA） from aniline and formaldehyde was evaluated and the result showed ...The catalytic performance of co mmonly used heteropolyacids （H3PW12O40, H4SiW12O40 and H3PMO12O40 synthesis of 4,4＇-methylenedianiline （4,4＇-MDA） from aniline and formaldehyde was evaluated and the result showed that H4SiW12O40 with moderate acid strength exhibited the best catalytic performance. Then HaSiW12O40@MIL-100（Fe） was prepared by encapsulating H4SiW12O40 within the pores of MIL-100（Fe） to facilitate its recovery and reuse. The prepared H4SiW12O40@MIL-100（Fe） was characterized by means of FT-IR, N2 adsorption-desorption, XRD, TG and then the catalytic performance was evaluated. The result showed that H4SiW12O40 was highly dispersed in the pores of MIL-100（Fe）, and both the Keggin structure of HaSiW12O40 and the crystal skeleton structure of MIL-100（Fe） could be effectively/preserved. Furthermore, H4SiW12O40@ MIL-100（Fe） showed excellent catalytic performance under the following reaction conditions： a molar ratio of aniline to formaldehyde = 5, a mass ratio of catalyst to formaldehyde = 1.2, a reaction temperature of 120 ℃ and a reaction time of 6 h. Under the above reaction conditions, the conversion of aniline was 41.1%, and the yield and selectivity of 4,4＇-MDA were 81,6% and 79.2%, respectively. Unfortunately, an appreciable loss in the catalytic activity of the recovered H4SiW12O40@MIL-100（Fe） was observed because of the blocking of the pores and the change of the acidity resulted from the adsorption of alkaline organics such as aniline and 4,4＇-MDA. The adsorbed alkaline organics could be cleaned up when the recovered catalyst was washed by methanol and DMF. Then the catalyst was effectively reused up to three cycles without much loss in its activity.展开更多
The crystal structure of the new title compound 2-ethoxy-3-n-butyl- benzofuro[2,3d]pyrimidin-4（3H）-one （C16H18N2O3, Mr = 286.32） has been prepared and determined by singlecrystal X-ray diffraction. The crystal is ...The crystal structure of the new title compound 2-ethoxy-3-n-butyl- benzofuro[2,3d]pyrimidin-4（3H）-one （C16H18N2O3, Mr = 286.32） has been prepared and determined by singlecrystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 13.7167（14）, b = 13.113（1）, c = 8.378（1） A, β = 98.992（2）^o, V = 1488.4（3） A^3, Z = 4, Dc = 1.278, F（000） = 608, μ = 0.089 mm^-1, MoKa radiation （2 = 0.71073）, R = 0.0498, wR = 0.1238 for 2336 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that all ring atoms in the benzo[4, 5]furo [2,3-d] pyrimi- dinone moieties are almost coplanar.展开更多
基金Supported by the National Natural Science Foundation of China。
文摘Al/TiO_(2) self-combustion synthesis reaction has been studied,including the effect of initial conditions of reactants on combustion temperature,combustion velocity and combustion stability etc.The reaction mechanism of Al/TiO_(2) self-combustion synthesis has been studied emphatically and the dynamic reaction model has been created.
基金This work is supported by Collaborative Innovation Center of Suzhou Nano Science and Technology, Ministry of Science and Technology of China （No.2014CB932700）, the National Natural Science Foundation of China （No.21603208, No.21573206, and No.51371164）, the China Postdoctoral Science Foundation （No.2015M580536, No.2016T90569）, Key Research Program of Frontier Sciences, CAS （QYZDBSSW- SLH017）, Strategic Priority Research Program B of the CAS （No.XDB01020000）, Hefei Science Center, CAS （No.2015HSC-UP016）, and Fundamental Research Funds for the Central Universities.
文摘Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mgPt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst （0.20 A/mgPt）. Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.
文摘A novel in-situ process-Reaction Synthesis has been used to fabricate Al/TiC compos-ites,the phase constitute,microstructure and mechanical property of the Al/TiC composite have been investigated by the use of XRD and SEM.It has been shown that the reaction synthesized TiC particu-late is submicron in size(about 0.1~0.8μpm),spherical in shape and smooth in surface.In macrostruc-ture the distribution of the TiC particulate in matrix is homogeneous,but in micostructure there is micro-segregation of the TiC particulate at the intergrannular.The cast structure become fine because of the existence of the TiC particulate.In addition«with the increasing of weight percentage of TiC partic-ulate in alloy,the yield strength and ultimate tensile strength of the composite increase significantly«e.g.at 15%TiC,117% and 103% increase respectively,in the same time the elongation of the composite is still more than 4.5%.In the end,the analysis has been done by SEM on the fracture morphology of the composite.The results show that the fracture is ductility,and mainly because of the cluster of TiC particulate to intergrannular and the synthesis of bar morphology Al_(3)Ti.
基金Supported by the Key Program of the National Natural Science Foundation of China(No.30930074)National Natural Science Foundation of China(No.31260160)
文摘The reaction mechanism of glyoxal （G） with urea （U） under weak acid condition was theoretically investigated at PW91/DNP/COSMO of quantum chemistry using density functional theory （DFT） method. The results show that the addition reaction of G with U under the conditions mainly involves the reactions of U with protonated glyoxal （p-G）, protonated 2,2-dihy- droxyacetaldehyde （p-G 1） and protonated bis-hemdiol （p-G2） to form two important carbocation reactive intermediates of C-p-UG and C-p-UG1, and two important hydroxyl compounds of UG and UG1. These compounds play important roles in the formation of UG resin. According to the result of quantum chemical calculation, UG resin was synthesized successfully under weak acid conditions. The UG resin was characterized by matrix assisted laser desorption ionization time of flight mass spectrometry （MALDI-TOF-MS）, ultraviolet and visible spectroscopy （UV-vis）, Fourier transform infrared spectroscopy （FT1R） and nuclear magnetic resonance spectroscopy （13CNMR and 1HNMR）. These instrumental analytical results agree with each other and further confirm the addition reaction pathway of glyoxal with urea proposed by quantum chemical calculation.
文摘The reaction of two series of 2,3-dihydro-1,5-henzothiazepines Ⅰ with dichloro- carbene,gave azirino[2,1-d][1,5]benzothiazepines Ⅷ,azirino[2,1-e][1,6]benzothiazocines Ⅸ, pyrrolo[2,1-b][1,3]benzothiazoles Ⅹ,substituted-cyclopropanes Ⅺ and 2H-1,4-benzothiazin-2-ones Ⅻ.The structures of these products were confirmed by the analytical and spectral data.Compound Ⅷ and Ⅸ are two new ring systems.
文摘Proton NMR-spectra of Wang resin bound compounds were obtained using the magic angle spinning 1HNMR technique with standard equipment. It was possible to analyse the spectra to evaluate their utility in solid-phase chernistry. A typical example was presented, which could directly monitor solid-phase reactions
文摘The acetalization of a series of carbonyl compounds with ethanediolwas performed over two self-steaxned HY zeolle catalpsts' The acetal and ketaiproducts were obtained with high ytelds Espectw, the HY zeollte with highfraxnework Si/A1 ratio was proven to be suitable cataipst for the acetabotion ofunsaturated carbonyl compounds, during which the C =C double bond was notperturbed
文摘Three kinds of products have been separated from the reaction mixtures of 1,2-dihydro-2, 4-disubstituted-1,5-benzodiazepine with: CCI_2.Besides the addition products of: CCI_2 to C=N.the inserted products of: CCI_2 to N-H and C-H single bonds were obtained, too.
文摘Direct reaction synthesis(DRS), based on the principle of self-propagating hightemperature synthesis (SHS), is a new method for preparing particulate metal matrix composites (PMMCs). The effects of the temperature of the aluminum melt and the aluminum content in the preform on the phases and structure of the reacted preform have been investigated by X-ray diffraction and scanning electron microscopy.It has been shown that TiC phase is prone to be synthesized with the increasing of the temperature of the aluminum melt and the decreasing of the aluminum powder content in the preform, and that the size of TiC particle becomes fine with the increasing of the temperature and the decreasing of the aluminum powder content.
文摘Asymmetric syntheses of both enantiomerically pure (+) and (-) 5-oxo-endo-tricyclo [5.2.1.0.^(2,6)] deca-3, 8-diene 1 was described. The key step is the use of enzyme-catalyzed hydrolysis of meso-diacetate 5.
文摘Dihydro-1-benzoyl-1,5-benzodiazepines react with (ethoxycarbonyl)carbenes to give 4H-azirino-[1,2-a][1,5]-benzodiazepines and unexpected new tin9 system 1H-pyrrolo-[1,2-a][1,5]-benzodiazepines. Dihydro-1,5-benzothiazepines react with (ethoxycarbonyl)carbenes in cyclohexane to gire unexpected rin9 cleavage products ethyl (2E, 4E)-3-aryl-2-arylthiohexadienoates.
基金This work was supported by the National Natural Science Foundation of China and Shanxi Natural Science Foundation
文摘As models of 5, 10-methenyl-tetrahydrofolate coenaymes imidazolinium salts 6a. b were synthesized and their carbon transfer reactions with several types of nucleophiles were studied.
文摘Three N,N-heterylmethyl derivates of diaza-18-crown-6(I) are readily prepared by the reaction of (I) with paraformaldehyde and heterocyclic compounds in dry benzene.
文摘Some telluronium salts react easily with 1,4-bis(3-substituted phenyl-3-oxo-1-propenyl)benzene and 1,5-disubstituted phenyl-1,4-pentadien-3 -one to afford derivatives of biscyclopropanes in 61.8-88.8% yield.
文摘The 1.3-dipolar cycloaddition reaction of 2-trifluoromethyl- oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.
基金supported by Hebei Iron and Steel Joint Fund, China (No.E2014209273)
文摘CaZrO3 powder was prepared using CaO,CaCO3 and Ca(OH)2 as calcium source,nano m-ZrO2 powder,micron m-ZrO2 powder,micron CaO partially stabilized ZrO2(Ca-PSZ)powder as zircon source,through high temperature solid reaction.Effect of the calcination temperature(800,900,1000,1100,1200,1300,1400,1500,and 1600℃)and the holding time(3,4,and 5 h)on the phase composition change was studied to research the synthesis mechanism.The synthesized CaZrO3 powder was mixed with CaO,MgO,Al2O3,Cr2O3,SiO2,and ZrO2 powder separately and fired at 1500℃for 3 h to prepare specimens to research the high temperature chemical stability of CaZrO3 with different reaction mediums.The results show that during the synthesis process,the CaZrO3 content does not always increase with the increasing calcination temperature or the prolonging holding time,CaZrO3 decomposes resulting from the diffusion of Ca2+and O2-in CaZrO3 to m-ZrO2 or c-ZrO2.At high temperatures,when CaZrO3 is in alkaline environment(such as environment containing CaO or MgO),the high temperature chemical stability is high,but when CaZrO3 is not in alkaline environment(such as environment containing Al2O3,Cr2O3,SiO2 or ZrO2),the high temperature chemical stability is low.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50205005)
文摘The in situ synthesis method for titanium matrix composites （TMCs） has obvious technical and economical advantages over other traditional methods. Ultrafine reinforcement particles were formed in situ by chemical reaction between elements or between elements and compounds. Using the approach, contamination at the composite matrix/reinforcement particle interface did not occur, interface bonding was good, and the reinforcement particle was thermodynamically stable. The stage of development of the preparation process for in situ TMCs as well as the thermodynamic analysis of the possible in situ reaction systems was described.
基金Supported by the National Natural Science Foundation of China(21236001,21476058,21506046)
文摘The catalytic performance of co mmonly used heteropolyacids （H3PW12O40, H4SiW12O40 and H3PMO12O40 synthesis of 4,4＇-methylenedianiline （4,4＇-MDA） from aniline and formaldehyde was evaluated and the result showed that H4SiW12O40 with moderate acid strength exhibited the best catalytic performance. Then HaSiW12O40@MIL-100（Fe） was prepared by encapsulating H4SiW12O40 within the pores of MIL-100（Fe） to facilitate its recovery and reuse. The prepared H4SiW12O40@MIL-100（Fe） was characterized by means of FT-IR, N2 adsorption-desorption, XRD, TG and then the catalytic performance was evaluated. The result showed that H4SiW12O40 was highly dispersed in the pores of MIL-100（Fe）, and both the Keggin structure of HaSiW12O40 and the crystal skeleton structure of MIL-100（Fe） could be effectively/preserved. Furthermore, H4SiW12O40@ MIL-100（Fe） showed excellent catalytic performance under the following reaction conditions： a molar ratio of aniline to formaldehyde = 5, a mass ratio of catalyst to formaldehyde = 1.2, a reaction temperature of 120 ℃ and a reaction time of 6 h. Under the above reaction conditions, the conversion of aniline was 41.1%, and the yield and selectivity of 4,4＇-MDA were 81,6% and 79.2%, respectively. Unfortunately, an appreciable loss in the catalytic activity of the recovered H4SiW12O40@MIL-100（Fe） was observed because of the blocking of the pores and the change of the acidity resulted from the adsorption of alkaline organics such as aniline and 4,4＇-MDA. The adsorbed alkaline organics could be cleaned up when the recovered catalyst was washed by methanol and DMF. Then the catalyst was effectively reused up to three cycles without much loss in its activity.
基金This work was supported by the Natural Science Foundation of Hubei Province (2006ABB016)National Natural Science Foundation of China (20672041) Key Project of Science and Technology of Ministry of Education of China (107082, 106116)
文摘The crystal structure of the new title compound 2-ethoxy-3-n-butyl- benzofuro[2,3d]pyrimidin-4（3H）-one （C16H18N2O3, Mr = 286.32） has been prepared and determined by singlecrystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 13.7167（14）, b = 13.113（1）, c = 8.378（1） A, β = 98.992（2）^o, V = 1488.4（3） A^3, Z = 4, Dc = 1.278, F（000） = 608, μ = 0.089 mm^-1, MoKa radiation （2 = 0.71073）, R = 0.0498, wR = 0.1238 for 2336 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that all ring atoms in the benzo[4, 5]furo [2,3-d] pyrimi- dinone moieties are almost coplanar.
