The one-pot synthesis of dimethyl carbonate（DMC） with co-production of propy-lene carbonate（PC） and propylene glycol（PG） from propylene oxide（ PO）, carbon dioxide and methanol as the starting materials was inv...The one-pot synthesis of dimethyl carbonate（DMC） with co-production of propy-lene carbonate（PC） and propylene glycol（PG） from propylene oxide（ PO）, carbon dioxide and methanol as the starting materials was investigated. The catalyst adopted here was a mixture of tetrabutyl ammonium bromide and sodium methoxide. It was found that un- der the reaction conditions of t = 150 ℃, p =3-4 MPa and 2 h, the PO conversion could reach 100%, the DMC, PC and the PG selectivities were 49. 7%, 42. 7% and 49. 8%, respectively, and the selectivity of by-products was below 10%.展开更多
Several potential failure modes generally exist in rock slopes because of the existence of massive structural planes in rock masses. A system reliability analyses method for rock slopes with multiple failure modes bas...Several potential failure modes generally exist in rock slopes because of the existence of massive structural planes in rock masses. A system reliability analyses method for rock slopes with multiple failure modes based on nonlinear Barton-Bandis failure criterion is proposed. The factors of safety associated with the sliding and overturning failure modes are derived, respectively. The validity of this method is verified through a planar rock slope with an inclined slope top and tension crack. Several sensitivity analyses are adopted to study the influences of structural-plane parameters, geometric parameters, anchoring parameters and fracture morphology on the rock slopes system reliability.展开更多
A novel compound was synthesized and characterized by means of elemental analysis, IR and UV spectra, TG, CV and single crystal X-ray diffraction. The compound crystallized in an orthorhombic space group C222 with a =...A novel compound was synthesized and characterized by means of elemental analysis, IR and UV spectra, TG, CV and single crystal X-ray diffraction. The compound crystallized in an orthorhombic space group C222 with a = 1. 622 4(3) nm, b=3. 498 4(7) nm, c=l. 301 5(3) nm,V=7. 387(3) nm3, Z = 6, R1 = 0. 037 3, wR2 = 0. 114 0. The Ala (Ala = alanine) molecules were protonated at the amino nitrogen N (1) and the C (2) of Ala group with the terminal oxygen atom O(15), O(14), O(26) and O(27) of the polyoxometalates participating in the hydrogen bond network. The anti-tumor activity of the title compound was estimated against Hela and Pc-3m cancer cells.展开更多
A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu（naphdien）]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and d...A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu（naphdien）]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and determined by single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/c, with a = 7.3490（15）, b = 7.0847（16）, c = 30.845（3）A, β= 95.33（3）°, V = 1599.0（5）A3, Z = 4, C15 H20ClCuN3O2, Mr = 373.33, De = 1.551 g/cm3, μ = 1.543 mm^-1, F（000） = 772, R = 0.0536 and wR = 0.0927 for 2788 unique reflections with 1659 observed ones （I 〉2σ（I））. In the crystal structure, mononuclear units [Cu（naphdien）]Cl·H2O are linked into a two-dimensional framework via strong hydrogen bonds, and extended into a three-dimensional supramolecular structure through π-π stacking interactions.展开更多
A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use o...A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 （CO3）4 （OH）2·4H2O were characterized by means of X-ray diffractometry （XRD）, fieldemission scanning electron microscopy（FE-SEM）. Brunauer-Emmett-Teller（BET） surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 （CO3）4（ OH）2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol.展开更多
A novel dimer tungstovanadate, (H 3O) 4[VW 12 O 40 Na(H 2O) 4] 2, was hydrothermally synthesized and structurally characterized by single crystal X ray diffraction, IR spectra, TGA DSC thermal analysis...A novel dimer tungstovanadate, (H 3O) 4[VW 12 O 40 Na(H 2O) 4] 2, was hydrothermally synthesized and structurally characterized by single crystal X ray diffraction, IR spectra, TGA DSC thermal analysis and polarograpy. The yellowish crystal crystallized in the triclinic system, space group P1, a =1 464 5(3) nm, b =1 468 6(3) nm, c =1 411 1(3) nm, α=111 82(2)°, β=93 17(3)°, γ=117 47(3)°, V =2 210 6(8) nm 3, Z=1, D c=4 552 g·cm -3 , λ (Mo Kα )=0 071 073 nm, μ =31 402 mm -1 , F(000)=2 648, R =0 078 0. The title compound consists of two Keggin structure units linked together with two hydrated sodium cations to form a dimer with a porous structure with the pore dimension of 0 766 nm×0 778 5 nm. [WT5FZ]展开更多
A new layered mixed valence vanadium oxide, [CH 3NH 3] 2[(V ⅣO) 2(V ⅤO 4) 2], which contains interlamellar organic cations was prepared under hydrothermal conditions and its single crystal structure was determined. ...A new layered mixed valence vanadium oxide, [CH 3NH 3] 2[(V ⅣO) 2(V ⅤO 4) 2], which contains interlamellar organic cations was prepared under hydrothermal conditions and its single crystal structure was determined. It crystallizes in a triclinic system with space group P 1, a =0 625 59(8) nm, b =0 639 84(9) nm, c =0 747 19(10) nm, α =78 718(2)°, β =80 099(2)°, γ =77 100(2). The compound contains mixed valence V 4+ /V 5+ vanadium oxide layers constructed from VO 4 tetrahedra, pairs of edge sharing VO 5 square pyramid and methylamine with protonated organic amines occupying the interlayer space.展开更多
The polyoxometalate-imidazole ionic liquids（POM-ILs） with low melting points at 94.5 and 95.5 ℃, [Cn mim]a[MosO26]（Cn mim=1-alkyl-3-methylimidazolium, n=12,14）, have been successfully synthesized and characterize...The polyoxometalate-imidazole ionic liquids（POM-ILs） with low melting points at 94.5 and 95.5 ℃, [Cn mim]a[MosO26]（Cn mim=1-alkyl-3-methylimidazolium, n=12,14）, have been successfully synthesized and characterized by DSC, single-crystal X-ray diffraction and TGA, etc. The two POM-ILs have relatively high stability with decomposing temperature up to about 347 and 344 ℃, respectively. Further photocatalytic performance was measured via the degradation of rhodamine B（RB） in aqueous solution. The experiments show that the conversion reached to 90% after 90 min under UV-light and the degradation efficiency depended on pH value, different dosages and so on. In addition, the catalysts can be recycled for several times without significant loss of activity.展开更多
Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu（ Ⅱ ） salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly（vinylpyrrolidone） （PVP） under different cond...Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu（ Ⅱ ） salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly（vinylpyrrolidone） （PVP） under different conditions. The morphologies and the crystalline structures of the products were characterized by using scanning electron microscopy （SEM）, transmission electron microscopy（TEM）, selected-area electron diffraction（ SAED）, and powder X-ray diffraction（XRD）. In particular, the influences of the solvothennal reaction temperature and alkalinity on the products were investigated. A lower temperature and a lower alkali concentration favor the formation of the Cu2O phase, whereas a higher temperature and a higher alkali concentration generally lead to the formation of the Cu phase.展开更多
β-Co（OH）2 and Mg（OH）2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The p...β-Co（OH）2 and Mg（OH）2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction（SAED）,and gas chromatograph.展开更多
The title compound, (H2en)3H3O{Mo8V4O36(VO4) (VO)2} ?4H2O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclin...The title compound, (H2en)3H3O{Mo8V4O36(VO4) (VO)2} ?4H2O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclinic system with space group P21/c, a=1. 980 4(4) nm, 6=2. 063 4(4) nm, c=l. 192 0(2) nm, =94. 76(3)?and deep black colour. The compound contains V-centered bi-capped a-Keggin fragments {Mo8V7O42} that are linked together by edge-shared units V O5 via V桹梀 bonds, forming a chain.展开更多
The photochemical behavior of polyoxometalates（POMs）have been studied extensivelyIn homogeneous solutions［1-3]．However，the major drawback to the practical applications ofthe homogeneous systems is the high ...The photochemical behavior of polyoxometalates（POMs）have been studied extensivelyIn homogeneous solutions［1-3]．However，the major drawback to the practical applications ofthe homogeneous systems is the high water solubility of POMs，which impedes the readyrecovery and the reuse of the photocatalysts．Therefore，the preparation of insoluble POMs Isconsidered．More recently，we haveprepared insoluble POMs，i．e，Keggin－type microporousPOMs，H3PW12O40／SiO2 or H4SiW12O40／SiO2，and paratungstate A－containing pillaredcompound，Mg12Al6（OH）36（W7O24）·4H2O，for the purpose of photo－oxidation of aqueous展开更多
文摘The one-pot synthesis of dimethyl carbonate（DMC） with co-production of propy-lene carbonate（PC） and propylene glycol（PG） from propylene oxide（ PO）, carbon dioxide and methanol as the starting materials was investigated. The catalyst adopted here was a mixture of tetrabutyl ammonium bromide and sodium methoxide. It was found that un- der the reaction conditions of t = 150 ℃, p =3-4 MPa and 2 h, the PO conversion could reach 100%, the DMC, PC and the PG selectivities were 49. 7%, 42. 7% and 49. 8%, respectively, and the selectivity of by-products was below 10%.
基金Project(51978666) supported by the National Natural Science Foundation of ChinaProject(2018-123-040) supported by the Guizhou Provincial Department of Transportation Foundation, ChinaProject(2019zzts009) supported by the Fundamental Research Funds for the Central Universities, China。
文摘Several potential failure modes generally exist in rock slopes because of the existence of massive structural planes in rock masses. A system reliability analyses method for rock slopes with multiple failure modes based on nonlinear Barton-Bandis failure criterion is proposed. The factors of safety associated with the sliding and overturning failure modes are derived, respectively. The validity of this method is verified through a planar rock slope with an inclined slope top and tension crack. Several sensitivity analyses are adopted to study the influences of structural-plane parameters, geometric parameters, anchoring parameters and fracture morphology on the rock slopes system reliability.
文摘A novel compound was synthesized and characterized by means of elemental analysis, IR and UV spectra, TG, CV and single crystal X-ray diffraction. The compound crystallized in an orthorhombic space group C222 with a = 1. 622 4(3) nm, b=3. 498 4(7) nm, c=l. 301 5(3) nm,V=7. 387(3) nm3, Z = 6, R1 = 0. 037 3, wR2 = 0. 114 0. The Ala (Ala = alanine) molecules were protonated at the amino nitrogen N (1) and the C (2) of Ala group with the terminal oxygen atom O(15), O(14), O(26) and O(27) of the polyoxometalates participating in the hydrogen bond network. The anti-tumor activity of the title compound was estimated against Hela and Pc-3m cancer cells.
基金This work was supported by the National Natural Science Foundation of China (Nos. 20671011, 20331010, 90406002 and 90406024)the 111 Project (B07012) and Key Laboratory of Structural Chemistry Foundation (No. 060017)
文摘A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu（naphdien）]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and determined by single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/c, with a = 7.3490（15）, b = 7.0847（16）, c = 30.845（3）A, β= 95.33（3）°, V = 1599.0（5）A3, Z = 4, C15 H20ClCuN3O2, Mr = 373.33, De = 1.551 g/cm3, μ = 1.543 mm^-1, F（000） = 772, R = 0.0536 and wR = 0.0927 for 2788 unique reflections with 1659 observed ones （I 〉2σ（I））. In the crystal structure, mononuclear units [Cu（naphdien）]Cl·H2O are linked into a two-dimensional framework via strong hydrogen bonds, and extended into a three-dimensional supramolecular structure through π-π stacking interactions.
基金Supported by the National Natural Science Foundation of China(Nos.20671011,20331010,90406002and90406024)the 111 Project(No.B07012)the Key Laboratory of Structural Chemistry Foundation(No.060017).
文摘A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 （CO3）4 （OH）2·4H2O were characterized by means of X-ray diffractometry （XRD）, fieldemission scanning electron microscopy（FE-SEM）. Brunauer-Emmett-Teller（BET） surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 （CO3）4（ OH）2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol.
基金Supported financially by the Key laboratory of Inorganic Hydrothermal Synthesis of Jilin University
文摘A novel dimer tungstovanadate, (H 3O) 4[VW 12 O 40 Na(H 2O) 4] 2, was hydrothermally synthesized and structurally characterized by single crystal X ray diffraction, IR spectra, TGA DSC thermal analysis and polarograpy. The yellowish crystal crystallized in the triclinic system, space group P1, a =1 464 5(3) nm, b =1 468 6(3) nm, c =1 411 1(3) nm, α=111 82(2)°, β=93 17(3)°, γ=117 47(3)°, V =2 210 6(8) nm 3, Z=1, D c=4 552 g·cm -3 , λ (Mo Kα )=0 071 073 nm, μ =31 402 mm -1 , F(000)=2 648, R =0 078 0. The title compound consists of two Keggin structure units linked together with two hydrated sodium cations to form a dimer with a porous structure with the pore dimension of 0 766 nm×0 778 5 nm. [WT5FZ]
基金Supported by the National Natural Science Foundation of China(No.2 0 1710 10 )
文摘A new layered mixed valence vanadium oxide, [CH 3NH 3] 2[(V ⅣO) 2(V ⅤO 4) 2], which contains interlamellar organic cations was prepared under hydrothermal conditions and its single crystal structure was determined. It crystallizes in a triclinic system with space group P 1, a =0 625 59(8) nm, b =0 639 84(9) nm, c =0 747 19(10) nm, α =78 718(2)°, β =80 099(2)°, γ =77 100(2). The compound contains mixed valence V 4+ /V 5+ vanadium oxide layers constructed from VO 4 tetrahedra, pairs of edge sharing VO 5 square pyramid and methylamine with protonated organic amines occupying the interlayer space.
基金Supported by the National Natural Science Foundation of China(Nos20731002, 10876002)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No200800070015)+2 种基金the Program of Cooperation of the Beijing Education Commission, China(No20091739006)the Program of Cooperation of the Beijing Technology Commission, China(No Z09010300820902)the Program for New Century Excellent Talents in University of China
文摘The polyoxometalate-imidazole ionic liquids（POM-ILs） with low melting points at 94.5 and 95.5 ℃, [Cn mim]a[MosO26]（Cn mim=1-alkyl-3-methylimidazolium, n=12,14）, have been successfully synthesized and characterized by DSC, single-crystal X-ray diffraction and TGA, etc. The two POM-ILs have relatively high stability with decomposing temperature up to about 347 and 344 ℃, respectively. Further photocatalytic performance was measured via the degradation of rhodamine B（RB） in aqueous solution. The experiments show that the conversion reached to 90% after 90 min under UV-light and the degradation efficiency depended on pH value, different dosages and so on. In addition, the catalysts can be recycled for several times without significant loss of activity.
基金Supported by the National Natural Science Foundation of China(Nos. 20331010 and 90406002) and Specialized ResearchFund for the Doctoral Program of Higher Education(No. 20030007014).
文摘Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu（ Ⅱ ） salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly（vinylpyrrolidone） （PVP） under different conditions. The morphologies and the crystalline structures of the products were characterized by using scanning electron microscopy （SEM）, transmission electron microscopy（TEM）, selected-area electron diffraction（ SAED）, and powder X-ray diffraction（XRD）. In particular, the influences of the solvothennal reaction temperature and alkalinity on the products were investigated. A lower temperature and a lower alkali concentration favor the formation of the Cu2O phase, whereas a higher temperature and a higher alkali concentration generally lead to the formation of the Cu phase.
基金Supported by the National Natural Science Foundation of China(Nos.20331010,20671011,90406024and90406002)the 111 Project(No.B07012)the Key Laboratory of Structural Chemistry Foundation(No.060017).
文摘β-Co（OH）2 and Mg（OH）2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction（SAED）,and gas chromatograph.
文摘The title compound, (H2en)3H3O{Mo8V4O36(VO4) (VO)2} ?4H2O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclinic system with space group P21/c, a=1. 980 4(4) nm, 6=2. 063 4(4) nm, c=l. 192 0(2) nm, =94. 76(3)?and deep black colour. The compound contains V-centered bi-capped a-Keggin fragments {Mo8V7O42} that are linked together by edge-shared units V O5 via V桹梀 bonds, forming a chain.
基金National Natural Science Foundation of China(No.20071007)and the Foundation for University KeyTeacher by the Ministry of Education of China.
文摘The photochemical behavior of polyoxometalates（POMs）have been studied extensivelyIn homogeneous solutions［1-3]．However，the major drawback to the practical applications ofthe homogeneous systems is the high water solubility of POMs，which impedes the readyrecovery and the reuse of the photocatalysts．Therefore，the preparation of insoluble POMs Isconsidered．More recently，we haveprepared insoluble POMs，i．e，Keggin－type microporousPOMs，H3PW12O40／SiO2 or H4SiW12O40／SiO2，and paratungstate A－containing pillaredcompound，Mg12Al6（OH）36（W7O24）·4H2O，for the purpose of photo－oxidation of aqueous
基金This work wassupported by the Natural Science Foundation Council of China （No.20271007 and 20331010）and Specialized Research Fund for the Doctoral Program of Higher Education （No.20030007014）
