烯烃在HZSM-5分子筛上原位芳构化反应的研究

烯烃在ZSM-5分子筛上转化成芳烃的反应是一个非常复杂的反应,既包括聚合裂解反应,又包括氢转移、脱氢环化反应,同时也包括烷基转移和脱烷基等反应,对于这一复杂反应的机理研究较少.Vedrine等人[1]认为烯烃首先在酸性位上通过氢转移生成戊二烯正碳离子,接着环化以及扩环反应生成     

锇(Ⅳ)-高碘酸钾-偶氮氯膦-pC催化分光光度法测定痕量锇的研究

在1．0mol／L硫酸介质中，微量锇(IV)的存在对KIO4氧化偶氮氯膦-pC的褪色反应有明显的催化作用，据此建立微量锇的催化光度分析法、方法的检出限为0．0002μg／mL，锇(IV)的含量在0．0006—0．003μg/mL之间有良好的线性关系，反应在水相中进行，应用于贵金属精矿中锇的测定，结果满意．     

烯丙基二异雪松基硼烷的制备及其与羰基化合物的不对称反应

本文以(-)-α-雪松烯为原料, 制备了烯丙基二异雪松基硼烷(Icd~2B-CH~2CH=CH~2). 该手性硼烷很容易与醛反应生成相应的烯丙基取代的手性仲醇, 光学产率在60%e.e.左右. 与潜手性酮反应的光学产率低于30%e.e..     

A New Cyclohexene Oxide from Uvaria tonkinensis var. subglabra

A new compound, subglain B, was isolated from the stems of Uvaria tonkinensis var.subglabra and its structure was identified as 1S, 2R, 3S, 6R-1-benzoyloxymethylene-1,2-dihydroxy-3-benzoyloxy-6-chlorocyclohex-4-ene (1), by spectral evidences.     

一维链状配位聚合物[Cd(N-MeIM)2(SCN)2]n的结构表征和电化学性能研究(英)

A novel cadmium(Ⅱ) isothiocyanate complex [Cd(N-MeIM)₂(SCN)₂]_n(N-MeIM=N-methylimidazole) has been prepared and characterized by spectroscopic analysis and crystallographic method. The title compound crystallize in the Triclinic system, space group P1, with lattice parameters a=0.589 50(12) nm, b=0.785 70(16) nm, c=0.882 00(18) nm, α=110.98(3)°, β=106.49(3)°, γ=95.08(3)°, and Z=1. The title compound exhibits an infinite chain structure in which each pair of Cd atoms is bridged by two η-1,3-SCN^- groups. The unique Cd atom lies on an inversion centre and the coordination sphere is completed by two N-MeIM N atoms to form a CdS₂N₄ octahedron. The polymeric chains are further extended into three-dimensional network via π…π stackings interactions between the imidazole rings. The cyclic voltammetry behaviors of the compound on glass carbon electrode showed a typical irreversible process. CCDC: 265283.     

EFFECTS OF K_2O AND MnO PROMOTERS ON THE PRODUCTION OF LIGHT ALKENES VIA SYNGAS OVER Fe/SILICALITE-2 CATALYST I.ACTIVITY OF K-Fe-MnO/SILICALIT-2 CATALYST

The activity and the selectivity to light alkenes of silicalite-2 (Si-2) zeolite supported F'e catalyst tor CO hydrogenation can he improved obviously with the addition of K2O and MnO promoters. The results of CO hydrogenation, CO-TPD, CO/H2-TPSR, C2H4/H2-TPSR and C2H4/H2 pulse reaction over K-Fe-MnO/Si-2 catalysts clearly show that the K2O additive into Fe-MnO/Si-2 catalyst leads to a remarkable increase in both the capacity and strength of the strong CO ad-species that will produce much more |Cad| via their disproportionation at higher temperatures. This results in an increase in the CO conversion and the selectivity to light olefins, and a decrease in CH4 formation. Moreover, K2O can suppress the disproportionate of C2H4 that occurs during the reaction as a side-reaction Meanwhile, the MnO promoter mainly prohibits the hydrogenation of C2H4 and C3H6, which is favorable to enhancing the selectivity to C2H4 and C3H6 and decreasing the formation of C2H6, and C3H8. It is also of interest that MnO has har     

Hydrothermal Synthesis and Electrochemical Properties of Complex Cu(CH3C6H4COOH)2(2,2''-bipy)·(H2O)

The title complex has been synthesized by 4-methylbenzoic acid and 2,2'-bipyridine (bipy) in the mixed solvent of water and methanol. It crystallizes in the triclinic system, space group (P1-) with a = 0.7047(3), b = 1.1217(5), c = 1.6718(7) nm, α = 103.826(7), β = 90.772(6), γ = 104.195(6)°, C26H25CuN2O5.50, Mr = 517.02, V = 1.2404(9) nm3, Dc = 1.384 g/cm3, Z = 2, F(000) = 536, μ(MoKα= 0.921 mm-1, R = 0.0782 and wR = 0.2172. Structural analysis shows that the copper atom is coordinated with three oxygen atoms from two 4-methylbenzoic acids and one water molecule together with two nitrogen atoms from 2,2'-bipyridine, giving a distorted square-pyramid coordination geometry. The cyclic voltametric behavior of the complex has also been described.     

MoS2纳米管包覆单壁碳纳米管束的制备

MoS₂ nanotube coated SWNT (Single wall carbon nanotube) bundles have been successfully prepared by adsorbing (NH₄)₂MoS₄ onto SWNT bundles and subsequent heat treatment under H₂ at 900 ℃ in a tube furnace. The morphologies, structure and composition of the as-prepared sample were investigated by XRD, SEM, HRTEM coupled with EDS. The formation mechanism has also been preliminarily discussed.     

Preparation and characterization of a novel pH-sensitive ion exchange resin

Methylacrylic acid/styrene cross-linked with divinylbenzene is a novel pH-sensitive ion exchange resin. Microspheres of this resin were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The microspheres showed a pulsatile swelling behavior when the pH of the media changed. The pH-sensitive microspheres were loaded with salbutamol sulfate and the drug-release characteristics were studied under both simulated gastric and intestinal pH conditions. The results obtained showed that the drug release also depended on the pH of the release media.     

[Cu3(μ10-bta)(μ2-C2O4)(H2O)2]n的水热合成与结构表征

有机-无机杂化材料因其在催化、化学吸附、磁性和电子导体等方面具有广泛的应用而成为人们的研究热点[1,2]. 通过过渡金属离子和特殊的有机配体之间的反应, 一系列具有独特结构的配位聚合物已被合成出来. 多齿有机配体可螯合两个或多个金属离子, 这些金属离子之间存在良好的电子交换[3], 可形成一维、二维或三维的配位聚合物. 均苯三甲酸和均苯四甲酸都是良好的桥连多齿配体, Chui等采用均苯三甲酸合成了具有吸附作用的大孔道的[Cu3(tma)2(H2O)]n[4] (tma=benzene-1,3,5-tricarb-oxylate)三维配位聚合物, 并且[Ni(C12H3ON6O2)]3(tma)*H2O[5], [M(tma)2]*12H2O(M=Co,Ni,Zn)[6], Na2[Co(H2O)6(bta)]*4H2O[7] (bta=benzene-1,2,4,5-tetracarboxylate)和[Co(phen)(md)][8] (phen=1,10-phenanthroline, md=benzene-1,3-dicarboxylate)等配位聚合物也先后被合成出来.