Synthesis and pervaporation performance of high-reproducibility silicalite-1 membranes

High-reproducibility silicalite-1 membranes were synthesized on silica tubes by in-situ hydrothermal synthesis, and the relative standard deviation （R.S.D.） of average separation factor for eight membranes was only 7.5%. By using an effective method called ＂solution-filling （SF）＂, the average flux of membranes prepared with SF method was improved by about 49% compared to membranes prepared without SF method, and the highest flux of membrane prepared with SF method towards ethanol/H2O mixture at 80℃ was 1.49 kg/（m^2·h）. Pervaporation experiments showed that the fluxes of silicalite-1 membranes at 60℃ were 2.63, 0.87, 0.24, and 0.20 kg/（m^2·h） towards methanol/H2O, ethanol/H=O, 2-propanol/H2O, and 1-propanol/H2O mixtures, respectively, and the corresponding separation factors were 22, 69, 81, and 159, respectively.     

Experimental and kinetic study on ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures by shock tube

Ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures with hydrogen amount-of-substance fractions ranging from 0–20% were measured in a shock tube facility.The ambient temperature varied from 1422 to 1877 K and the pressure was maintained at 0.4 MPa behind the reflected shock wave.The experiments were conducted at an equivalence ratio of 2.0.The fuel mixtures were diluted with nitrogen gas so that the nitrogen amount-of-substance fraction was 95%.The experimental ignition delay time of the CH4/H2 mixture decreased as the hydrogen amount-of-substance fraction increased.The enhancement of ignition by hydrogen addition was weak when the ambient temperature was >1750 K,and strong when the temperature was <1725 K.The ignition delay time of 20% H2/80% CH4 was only one-third that of 100% CH4 at 1500 K.A modified model based on GRI-Mech 3.0 was proposed and used to calculate the ignition delay times of test mixtures.The calculated results agreed with the experimental ignition delay times.Normalized sensitivity analysis showed that HO·+H2 →H·+H2O was the main reaction for the formation of the H· at 1400 K.As the hydrogen amount-of-substance fraction increased,chain branching was enhanced through the reaction H·+O2→O·+HO·,and this reduced the ignition delay time.At 1800 K,the methyl radical (H3C·) became the key species that influenced the ignition of the CH4/H2/O2/N2 mixtures,and sensitivity coefficients of the chain termination reaction 2H3C·(+M)→C2H6(+M),and chain propagation reaction HO2+H3C·→HO·+CH3O decreased,which reduced the influence of hydrogen addition on the ignition of the CH4/H2 mixtures.     

Synthesis, structure and superoxide dismutase activity of two self-assembly transition metal complexes containing a tridentate amino-Schiff base deviating from salicylaldehyde with glycine

Two new transition metal （Cu, Ni） complexes with amino-Schiff base ligand, （CgH7NO3）Cu（C14H12N2）.H2O （1） and （C9HTNO3）Ni（C3H4N2）3.H2O （2）, have been designed and synthesized in ethanol solution at room temperature. Both of the complexes have been characterized by elemental analysis, IR spectra, UV-vis spectroscopy and X-ray single crystal diffraction. For complex 1, the coordination environment of the central copper atom is a distorted square pyramid, and one-dimensional chain is formed through the inter-molecular hydrogen bonds （O4-H2W…O3, O4…H2W…O3#1 （#1： -x＋1, y, -z＋3/2）） and weak interactions （∏-∏ stacking interaction） between the phenyl rings. For complex 2, the nickel atom is 6-coordinated and in a distorted octahedral environment, and a discrete hydrogen-bond cluster （four molecules are connected by hydrogen bonds into a group） is formed via two types of intra-molecular hydrogen bonds （O-H...O, N-H...O） and inter-molecular hydrogen bonds （O-H...O, N-H...O）.     

A facile way to prepare visible light driven tin oxide based photoanode and its photoelectrochemical water splitting properties

Visible light driven tin oxide based photoelectrodes were obtained using SnCl2·2H2O EtOH solution on FTO by dipping and with further heat treatment in air.Photoelectrochemical measurement with three electrodes configuration under visible light irradiation(λ>420 nm) revealed that this as-prepared photoelectrode showed typical n-type photocurrent effect and the onset potential is negative than that of H+/H2.XRD,UV-Vis spectrum and control experimental results revealed that the visible light driven mechanism for the tin oxide based photoanode maybe ascribed to Sn4+/Sn2+ transformation and the surface oxygen deficiency.     

水合磷酸铁铵的低热固相合成及其对乙酸丁酯的催化作用

以Fe2(SO4)3与NH4H2PO4·12H2O为原料,PEG-400为表面活性剂,经低热固相反应合成得到水合磷酸铁铵,经XRD分析表征确定其分子式为Fe3(NH4)(PO3(OH)0.666O0.333)3(PO2(OH)2)3(H2O)6Fe3H23.998NO29.997P6后,用其作为催化剂进行乙酸丁酯的合成试验。试验应用均匀设计试验法及数据挖掘技术,在数据挖掘成果的指导下考察反应时间、醇酸物质的量比及催化剂用量等因素对收率的影响。获得催化反应的最佳工艺条件是反应时间6h,醇酸物质的量比1.56∶1,催化剂用量1.73g。在这个最优的工艺条件下,水合磷酸铁铵催化合成乙酸丁酯的收率可达到98.6%。水合磷酸氢铁铵不仅合成工艺简单,可行,而且作为乙酸丁酯的催化剂时,具有良好的催化活性,工业应用潜质大。     

Synthesis, crystal structure and properties of binuclear manganese complex [(bipy)2Mn2(μ-O)(μ-Ac)2(H2O)2](ClO4)2

Binuclear manganese complex [(bipy)₂Mn₂(μ-O)(μ-Ac)₂(H₂O)₂](ClO₄)₂ was synthesized by the reaction of MnAc₃ · 2H₂O with 2,2′-bipyridine in the HAc-NaAc buffer (pH = 4.0). X-ray diffraction result for the single crystal shows that the crystal is monoclinic, space group C₂/C, with a = 3.408 2(7),b = 0.864 4(2),c = 2.174 9(4) nm, β= 105.2∘, V=6.186(2) nm³, Z= 8. There are two very strong peaks of UV-Vis spectrum in the range of 400–600 nm, which are similar to those of Mn catalase and Mn ribonuleotide reductase extracted from organisms. Cyclic voltammogram shows that the complex in CH₃CN undergoes quasi-reversible one-electron reduction and oxidation at E_1/2=1.15V.     

Crystal structure and surface photo-electric property of Mn（Ⅱ） coordination supramolecules

Two Mn（Ⅱ） coordination supramolecules, [Mn2（C8HTO2）4（phen）2（p-H20）] （1） and [Mn2（btec）（phen）2（H2O）6]·2H2O （2） （phen=1,10-phenanthroline, H4btec=1,2,4,5-benzenetetracarboxylic acid）, were synthesized by hydrothermal method. The crystal structures of the complexes were determined by X-ray single crystal diffraction. The result indicates that （1） and （2） are both binuclear Mn（Ⅱ） complexes. The existence of hydrogen bonds makes the binuclear complexes become further connected to coordination supramolecules, which possess 1D and 3D infinite structures respectively. The complexes were identified by IR, UV-Vis, surface photovoltage spectrum （SPS） and field-induced surface photovoltage spectrum （FISPS）. The results of SPS for the complexes indicate that they both exhibit positive surface photovoltage response bands in the range of 300-600 nm. The SPS phase spectrum and FISPS of complexes indicate that they show certain p-type semiconductor characteristic. However, the intensity, position and number of the SPV response bands are different obviously. The difference of the SPV response bands is mainly attributed to the different structures of the complexes and the different coordination environment of Mn（ll） in the two complexes. This paper discusses the action of hydrogen bonds in the construction of the supramolecule and the change on the surface photovoltage of complex in different coordination environment.     

葡聚糖产生菌(Leuoconostoc mesenteroides)发酵培养基优化初步研究

采用单一因素确定法研究分离自明阳糖厂的一株肠膜明串珠菌菌株摇瓶发酵生产葡聚糖的适宜培养基 ,结果得到适宜培养基的组分为 :蔗糖 1 0 %、酵母膏 0 .4%、磷酸氢二铵0 .6%、磷酸二氢钾 0 .1 %、硫酸镁 0 .1 %、Mn Cl2 · 4H2 O0 .0 0 0 3%、Zn SO4· 7H2 O0 .0 0 0 5%、Fe SO4· 7H2 O0 .0 0 5%、Ca Cl2 · 2 H2 O0 .0 0 2 %。     

Synthesis, structure and property of serial p-carboxylphenoxyacetate-lanthanide coordination polymers

Four novel lanthanide-based coordination polymers, [Ln（PBDC）（HPBDC）（H2O）3] （H=PBDC=p-carboxylphenoxyacetate; Ln = La （1）, Pr （2）, Nd （3）） and [La=（PBDC）3（H2O）4] （4）, have been prepared through hydrothermal synthetic methods. Compounds 1-3 are isomorphous and exhibit one-dimensional （1D） chain-like motifs, while compound 4 features a complicated three-dimensional （3D） architecture, which is designed and synthesized based on the inspiration from the structure characterization of compound 1. Under the similar reaction conditions, the carboxyl in compound 1 may be further deprotonated by adding the organic base of 2,2′-bipyridine. This subtle change caused a significant difference in the structures, from 1D chain of 1 to a 3D structure of 4. In addition, IR, UV-Vis, TGA and magenetic properties are also investigated in this paper.     

Hydroxyl in continental deep subduction zone: Evidence from UHP eclogites of the Dabie Mountains

Infrared spectra in the region of 3 000 to 4 000 cm⁻¹ have been measured by an FTIR spectrometer on minerals in UHP eclogites from the Bixiling and Shuanghe areas, the Dabie Mountains. It is shown that omphacite is the most important hydrous mineral (100–200 μg/g) in UHP eclogites. Garnet and quartz contain virtually no H₂O or OH. Accessory mineral rutile contains a significant amount of OH (>1 000 μg/g). Coesite gives no indication of the presence of OH but apparent H₂O bands. The results have considerable implications for existing forms and contents of hydroxyl in the continental deep subduction zone, the eastern Dabie Mountains.     

Crystal structure and photoelectricity property of Fe(II/III) coordination supermolecules

Three new mixed-ligand Fe(II/III) complexes [Fe₂(μ₂–btec)(μ₂–H2btec)(phen)₂(H₂O)₂]_n (1), [Fe2(btec) (phen)₂(H₂O)₄] (2), and {[Fe(o-pha)(phen)(H₂O)]•H₂O}_n (3) (phen=1,10-phenanthroline, o-H₂pha=o-phthalic acid, H₄btec=1,2,4,5-benzenetetracarboxylic acid) have been hydrothermally synthesized and detected by single crystal X-ray diffraction, showing that complexes (1) and (2) are both bridged by the betc⁴⁻ ligands to form 1D chain and dinuclear structure and complex (3) is bridged by the o-pha groups to form 1D chain structure. The coordinated modes of the carboxyl groups adopt μ₂-η¹η¹ηη¹η¹ and μ₂-η²η¹ respectively in com-plexes (2) and (3). The betc groups in complex (1) show two different coordinated modes: μ₂-η¹η¹η¹η¹ and μ₂-η¹η¹. In addition, the hydrogen bonds and π…π type interactions make the complex molecule further connect to three-dimensional and two-dimensional networks respectively. These complexes are detected by IR, UV-Vis-NIR and surface photovoltage spectrum (SPS). The SPS of complexes (1)–(3) indicate that there are positive SPV responses in the range of 300–600 nm and show p-type semiconductor characteristic. Because the structure, the valence and the coordinative environment of the Fe ions are all different in the three complexes, the intensity, position and the number of the response bands are different obviously. The results of SPS are corresponding with UV-Vis-NIR spectra.     

Phase behavior and properties of salt-free cationic/anionic surfactant mixtures of oleic acid and stearic acid

Cationic base surfactant, tetradecyltrimethylammonium hydroxide （TTAOH）, can be obtained through anion exchange from tetradecyltrimethylammonium bromide （TTABr）. Salt-free cationic and anionic （catanionic） surfactant mixtures were studied by mixing TTAOH with oleic acid （OA） or stearic acid （SA） in water. The phase behavior of TTAOH/OA/H2O is compared with that of TTAOH/SA/H2O. It was found that the phase behavior of TTAOH/OA/H2O and TTAOH/SA/H2O system differs from each other due to the existence of the unsaturated double carbon bond （C=C） in OA. At fixed total surfactant concentration （25 mg/mL） of TTAOH/ONH2O system at 25℃, one can observe an isotropic L1 phase, and a L1/Lα two-phase region with increasing OA content. The volume of top turbid Lα phase increases while the bottom phase changes gradually from transparently clear to a bit turbid until a single Lα-phase is reached. Finally at high OA concentration, excess OA is separated from the bulk aqueous solutions. TTAOH/SA/H2O system usually forms white precipitating at 25℃ due to the high chain melting temperature of SA. When heated to 60℃, however, the state of samples changes. At fixed total surfactant concentration of 25 mg/mL, an isotropic Lα phase and a milk-white or bluish Lα-phase are observed with increasing SA concentration. Transparent thin layers which are strongly birefringent form at the tops of some samples within the Lα-phase region. Finally, at high SA concentration, excess SA is separated from the bulk aqueous solutions. In addition to phase behavior study, we also measured the conductivity of TTAOH/OA/H2O system at 25℃ and TTAOH/SA/H2O system at 60℃, respectively. Surface tension and rheological measurements were also performed on typical samples.     

微波辐射下苯氧乙酸锌、甘氨酸锌的固相合成及表征

研究了乙酸锌与苯氧乙酸,甘氨酸在微波辐射及这曙条件下的固－固相配位化学反应,通过固相反应一步合成了苯氧乙酸锌和甘氨酸锌。经电导率,ＩＲ,ＵＶ及元素分析表征了产物。     

Syntheses and lyotropic liquid crystal properties of a series of sandwich-type tungstoarsenates heteropoly compounds with As/W ratio of 4/30

A series of sandwich-type tungstoarsenates heteropoly compounds with As/W ratio of 4/30, Na16[As4W30M4(H2O)2O112]·XH2O (M = Zn,Cu,Co,Ni,Mn and Cd), have been synthesized for the first time and structurally characterized by elemental analysis, IR and 183W NMR spectra. The crystal structure of Na16[As4W30Cu4(H2O)2O112]·63H2O was determined to be a triclinic system, of P1 symmetry, a = 1.2721(3) nm, b = 2.451 6(5) nm, c = 2.6450(5) nm, α= 89.90(3)°,β= 77.32(3)°, γ= 89.96(3)°, 2=2. Using tetrahepty lammonium bromide as a phase transfer reagent, [As4W30Cu4(H2O)2O112]16- was transferred from aqueous solution to organic phase (benzene), and the heteropolyanion lost the coordination water molecules to form the coordination-unsaturated ion. After lactic acid was added to the benzene solution, the coordination-saturation was recovered. By esterification reaction between lactic acid and cholesterin, the latter was attached to the heteropolyanion indirectly. Therefore, a new type of lyotropic liquid crystal was obtained, which was characterized by a polarimicroscope, DSC and variable temperature wide-angle X-ray diffraction.     

A new 3-D Gd-Cu heterometallic polymer [Gd2Cu3（bpy）2- （ip）6]·6H2O with a non-interpenetrated α-Po net

A new 3-D porous Gd-Cu heterometallic polymer [Gd2Cu3（bpy）2- （ip）6]·6H2O （1） （bpy = 2,2′-bipyridine, H2ip = isophthalic acid） has been hydrothermally synthesized and structurally characterized. Compound 1 crystallizes in the triclinic space group P1and displays a 3-D non-interpenetrated α-Po net- work with 1-D channels filled transversely by the hexa-nuclear chain-like （H2O）6. The EPR and thermal stability of 1 were investigated.     

A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO4-H2O and NaF-H2O binary solutions and NaClO4-NaF-H2O ternary solution

A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO₄-H₂O and NaF-H₂O binary solutions and NaClO₄-NaF-H₂O ternary strong electrolyte aqueous solutions was developed based on the ion and molecule coexistence theory (IMCT). A transformation coefficient was needed to compare the calculated mass action concentration and the reported activity, because they were usually obtained at different standard states and concentration units. The results show that transformation coefficients between the calculated mass action concentrations and the reported activities of the same components change in a very narrow range. The transformed mass action concentrations of structural units or ion couples in NaClO₄-H₂O and NaF-H₂O binary solutions agree well with the reported activities. The transformed mass action concentrations of structural units or ion couples in NaClO₄-NaF-H₂O ternary solution are also in good agreement with the reported activities in a total ionic strength range from 0.1 to 0.9 mol/kg H₂O by the 0.1 mol/kg step with different ionic strength fractions of 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1, respectively. The results indicate that the developed thermodynamic model can reveal the structural characteristics of binary and ternary strong electrolyte aqueous solutions, and the calculated mass action concentrations of structural units or ion couples also strictly follow the mass action law.     

Simulation for the primary electronic donor of photosystem IIin vitro

Histidine coordinated to Chi a is a distinct characteristic of Chl ain vivo. By using histidine analogue of 1-methylimidazole (C₄H₆N₂2) and measuring the UV/vis absorption, CD and MCD spectra of the interaction between C₄H₆N₂ and Chl a in CCI₄, we have obtained that: (i) In pure CCl₄ solvent, Chl a molecule is in five-coordinate state, and two Chl a molecules form an asymmetric compact-dimer with strong coupling interaction. We propose that the two Chl a molecules are connected by two unequally coordinated Mg-O bonds (the two oxygen atoms come from the C=O of C13¹ keto and C17 ester, respectively); (ii) when the molar ratio of C₄H₆N₂/Chl a is 0.5 or 1 (corresponding to 2Chl a · 1C₄H₆N₂ and 2Chl a · 2C₄H₆N₂, respectively), significant changes have been observed in the absorption, CD and MCD spectra, which indicate that the Chl a remains in dimer form, but the coupling interaction between them reduces greatly. We postulate that C₄H₆N₂ replaces the ligation of C=O of C17 ester and C13¹ keto to Mg atoms sequentially. The two Chl a molecules linked by two weakly interacted Mg…O bonds form a relaxed-dimer. The structure of the model is essentially similar to that of the primary electronic donor, P₆₈₀, of photosystem II in high plants and algae.     

Photocatalytic degradation of microcystin-LR using TiO2 nanotubes under irradiation with UV and natural sunlight

In order to investigate the catalytic performance of anodic TiO2 nanotubes and their practical application in the treatment of refractory microcystins(MCs) in natural-water samples,TiO2 nanotubes of diameter of 50-80 nm were fabricated by anodization in C2H2O4·2H2O containing NH4F.Under irradiation with natural sunlight,MC-LR was totally degraded after 1 d using the anodic TiO2 nanotubes.In contrast,the removal efficiency without TiO2 nanotubes was as low as 47.7% within 20 d.In addition,a mixture of anatase and rutile TiO2 gave higher photocatalytic activity than the single phase did.The pH also influenced the adsorption capacity of the TiO2 nanotubes.The order of MC-LR degradation efficiencies at different pH values was 3.5 > 8.0 > 10.0.After five repeated experiments on the degradation of MC-LR for 7 h,the degradation efficiency was still stable.     

Shock tube study on auto-ignition characteristics of kerosene/air mixtures

Ignition delay times are obtained for kerosene/air mixtures behind the reflected shock waves at temperatures between 1445 and 1650 K,at a pressure of 0.11 MPa and an equivalence ratio of 1.0.A nebulization device with Laval nozzle is used to nebulize kerosene and form an aerosol phase,which evaporates and diffuses rapidly behind the incident shock waves.Mixtures auto-ignite behind the reflected shock waves.An ICCD is used to visualize the kerosene/air mixture’s ignition characteristics.The mixture’s ignition intensity increases with increase in initial temperature.Continuous and irregular flames exist below 1515 K while plane and discontinuous flames exist over 1560 K.Ignition delay times decrease with increase in initial temperature.Experimental data shows good agreement with results reported previously in the literature.A new surrogate (consisting of 10% toluene,10% ethylbenzene and 80% n-decane) is proposed for kerosene.Honnet et al.’s mechanism is used to simulate the ignition of kerosene with calculations agreeing well with the experimental data.The sensitivity of reaction H+O2 <=>OH+O,which shows the highest sensitivity to the ignition delay time,increases with an increase in temperature.The chain breaching reaction of CH3 with O2 accelerates the total reaction rate and the H-atom abstraction of n-decane controls the total reaction rate.The rate of production and instantaneous heat production indicate that two reactions,H+O2 <=>OH+O and O+H2 <=>OH+H,are the key reactions to the formation of OH radicals,as well as the main endothermic reaction.However,the reaction of R3 is the main heat release reaction during ignition.Flame structure analysis shows that initial pressure is increased slightly as CO and H2O will appear before main ignition.     

Synthesis and characterization 9-tungstosilicate complexes with transition metal

The title complexes K_aH_b[M(SiW₉O₃₄)₂]·mH₂O(M=Ni,Cu,Zn,Fe or Mn) were synthesized by SiW₉O₃₄ ¹⁰⁻ with transition metal respectively and their structure were characterized by mean of elemental analysis, TG-DTA, IR spectra and, UV spectra. In addition, their redox properties in solution were investigated using polarographic and cyclic voltammographic methods. Experimental results indicated that the complexes have Keggin structure and that the heteropolyanions underwent two-step, two-electron tungsten reduction processes. Biography: Jin Su-rong (1963-), female, Lecturer.