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91.
The texture of Cr2O3-K2O/Al2O3catalysts containing oxides of rare earth elements (REE) was studied. The catalysts are used for the synthesis of 2-methylthiophene by the reaction of H2S with n-pentane or piperilene. The heterocyclization of n-pentane is a consecutive reaction involving a step of dehydrogenation of initial hydrocarbon. At this step the texture of the catalyst affects the yield of 2-methylthiophene. The yield of 2-methylthiophene obtained from piperilene and I2S is independent of the catalyst texture. 相似文献
92.
Masahiro Murayama Ryoji Kanno Michihiko IrieShinya Ito Takayuki HataNoriyuki Sonoyama Yoji Kawamoto 《Journal of solid state chemistry》2002,168(1):140-148
The new lithium ionic conductors, thio-LISICON (LIthium SuperIonic CONductor), were found in the ternary Li2S-SiS2-Al2S3 and Li2S-SiS2-P2S5 systems. Their structures of new materials, Li4+xSi1−xAlxS4 and Li4−xSi1−xPxS4 were determined by X-ray Rietveld analysis, and the electric and electrochemical properties were studied by electronic conductivity, ac conductivity and cyclic voltammogram measurements. The structure of the host material, Li4SiS4 is related to the γ-Li3PO4-type structure, and when the Li+ interstitials or Li+ vacancies were created by the partial substitutions of Al3+ or P5+ for Si4+, large increases in conductivity occur. The solid solution member x=0.6 in Li4−xSi1−xPxS4 showed high conductivity of 6.4×10-4 S cm−1 at 27°C with negligible electronic conductivity. The new solid solution, Li4−xSi1−xPxS4, also has high electrochemical stability up to ∼5 V vs Li at room temperature. All-solid-state lithium cells were investigated using the Li3.4Si0.4P0.6S4 electrolyte, LiCoO2 cathode and In anode. 相似文献
93.
为观察二硫化碳(CS2)对机体铜,锌水平的影响,对某化纤厂35名接触CS2工人和41名非接触工人的血铜,锌值进行调查,比较,并进行了动物染毒实验。SD大鼠吸入CS2浓度分别为5和50mg/m^3,每日5h,每周6d,连续6个月,于染毒2,4,6个月时测定血浆铜,锌值及染毒6个月时肝脏铜,锌含量。结果显示,CS2接触组工人血铜,锌水平较对照组显著降低(P<0.05)。在CS2染毒6个月时,50mg/m^3 CS2染毒组血浆及肝脏铜水平均较对照组及5mg/m^3 CS2染毒组显著降低(P<0.05)。可见接触CS2能干扰机体铜,锌代谢,导致体内铜,锌含量减少。 相似文献
94.
Bart M. J. M. Suijkerbuijk Dr. Duncan M. Tooke Dr. Anthony L. Spek Prof. Dr. Gerard van Koten Prof. Dr. Robertus J. M. Klein Gebbink Prof. Dr. 《化学:亚洲杂志》2007,2(7):889-903
A series of meso‐tetrakis‐(ERE donor) zinc(II) porphyrins n Zn (ERE donor=4‐R‐3,5‐bis[(E)‐methyl]phenyl; 1 Zn: E=NMe2, R=Br; 2 Zn: E=NMe2, R=H; 3 Zn: E=OMe, R=Br; 4 Zn: E=OMe, R=H) have been synthesized in excellent yields. As a result of the combination of a Lewis acidic site and eight Lewis basic sites within one molecule, monomeric molecules of n Zn self‐assemble to form one‐dimensional porphyrin polymers [ n Zn]∞ in the solid state, as confirmed for 1 Zn and 3 Zn by X‐ray crystallography. The coordination environment around the zinc(II) ions in these polymers is octahedral. They are ligated by four equatorial nitrogen atoms of the porphyrin and two apical E atoms (E=N, O) provided by the EBrE donor groups of adjacent n Zn molecules. Complexes 2 Zn and 4 Zn did not form single crystals, but solid‐state UV/Vis analysis points to the formation of similar structures. Solution UV/Vis and 1H NMR spectroscopy indicated that interactions between 1 Zn and 2 Zn monomers in the polymers are stronger than between 3 Zn and 4 Zn monomers. Interestingly, they also revealed that the presence of a neighboring bromine atom in the EBrE donor groups has a considerable influence on the coordination properties of the benzylic N or O atoms. The zinc(II) ions of the porphyrins most likely adopt only hexacoordination in the solid state, owing to the unique predisposition of Lewis acidic and basic sites in the n Zn molecules. Several parameters of the aggregates, for example, the interplanar separation between porphyrins and the zinc–zinc distances, change as a function of the coordinating E groups. The high degree of modularity in their synthesis makes these zinc(II) porphyrins an interesting new entry in noncovalent multiporphyrin assemblies. 相似文献
95.
Chronoamperograms for gold in solutions containing 0.1 M thiourea, 0.5 M H2SO4, and catalytically active sulfide ions at the concentration c 1 from 1 × 10?5 to 4 × 10?5 M are obtained at different potentials with the aid of an automated setup intended for renewing the electrode surface directly in the solution by cutting off a thin surface layer of the metal. It is shown that the results of measurements of the current practically coincide at a constant value of the product c 1 t, where t is the time period elapsed after the renewal of the electrode surface. Such a coincidence testifies to a diffusion nature of processes that hamper accumulation of sulfide ions at the gold surface. This fact permitted the use of a procedure developed previously for the calculation of polarization curves at constant values of surface coverage θ by catalytically active ions. At θ = const, the voltammetric curves for gold in sulfide-containing thiourea solutions are shown to correspond to the Tafel equation. With the surface coverage increasing, the effective values of the exchange current i 0, transfer coefficient α, and anodic reaction order with respect to thiourea P a increase from the values i }~ 10?5 A cm?2, α }~ 0.12, and P a = 0.2, which are characteristic of pure solutions, to 2 × 10?4 A cm?2, α }~ 0.5, and P a = 1.1 (at θ }~ 0.5). An interpretation to the established regularities is given. 相似文献
96.
Takeshi SasakiHirotsugu Takizawa Kyota UhedaTakahiro Yamashita Tadashi Endo 《Journal of solid state chemistry》2002,166(1):164-170
Two new high-pressure phases of binary boron-sulfur compounds, B2S3-II and B2S3-III, were synthesized at 3-6.2 GPa. A single crystal of B2S3-III was grown and the structure was determined (tetragonal, space group I41/a, a=16.086(2) Å, c=30.488(4) Å; V=7888(1) Å3, Z=100, R=3.0% and Rw=2.8% for 3047 observed data [I>3.00σ(I)]. The structure of B2S3-III consists of two kinds of macrotetrahedra built up from 20 and 34 BS4-tetrahedra. These macrotetrahedra connect each other to form an interpenetrating zincblende-type structure by sharing BS4-tetrahedra at the corners of those. B2S3-III is anticipated having a rather disordered structure. From the UV-Vis diffuse reflectance spectrum, the optical band gap of B2S3-III was estimated to be 3.7 eV. 相似文献
97.
98.
芥子气模拟剂2-氯乙基乙基硫醚的光催化降解 总被引:4,自引:0,他引:4
利用连续流动微反、原位红外和GC/MS等手段考察了芥子气模拟剂2-氯乙基乙基硫醚(2-CEES)在P25 TiO2上的光催化降解反应,证实CO2和H2O是这个反应的最终产物.详细的跟踪分析表明,除了CO2和H2O外,在反应的气相混合物中可检测到C2H4、CH3CHO、CH4、CO、HCl和H2S;少量小分子的羧酸、醚和砜;微量C2H5SC2H5、C2H5S2C2H5、C2H5SC2H4Cl和CH2ClCH2Cl等中间产物;在反应后的催化剂表面可检测到C2H5S2C2H5、C2H5SC2H4OH、C4H9S2C2H5和C2H5S2C2H4OH、等物.根据这些结果提出了2-CEES光催化降解的反应机理,推断2-CEES的光催化降解涉及脱氯、C-S键断裂、有机硫化物光聚合和裂解等复杂过程最终转化为CO2和H2O.认为各种硫物种在表面的积聚引起了催化剂的缓慢失活. 相似文献
99.
Koushik Dhara Santanu Karan Jagnyeswar Ratha Partha Roy Goutam Chandra Mario Manassero Dr. Biswanath Mallik Dr. Pradyot Banerjee Dr. 《化学:亚洲杂志》2007,2(9):1091-1100
A 2D coordination compound {[Cu2(HL)(N3)]?ClO4}∞ ( 1 ; H3L=2,6‐bis(hydroxyethyliminoethyl)‐4‐methyl phenol) was synthesized and characterized by single‐crystal X‐ray diffraction to be a polymer in the crystalline state. Each [Cu2(HL)(N3)]+ species is connected to its adjacent unit by a bridging alkoxide oxygen atom of the ligand to form a helical propagation along the crystallographic a axis. The adjacent helical frameworks are connected by a ligand alcoholic oxygen atom along the crystallographic b axis to produce pleated 2D sheets. In solution, 1 dissociates into [Cu2(HL)2(H3L)]?2H2O ( 2 ); the monomer displays high selectivity for Zn2+ and can be used in HEPES buffer (pH 7.4) as a zinc ion selective luminescent probe for biological application. The system shows a nearly 19‐fold Zn2+‐selective chelation‐enhanced fluorescence response in the working buffer. Application of 2 to cultured living cells (B16F10 mouse melanoma and A375 human melanoma) and rat hippocampal slices was also studied by fluorescence microscopy. 相似文献
100.