Pt-Sn脱氢催化剂浸渍状态的Sn-119和Pt-195的多核NMR研究

测定了Ｐｔ－Ｓｎ型催化剂浸渍状态下的Ｓｎ－１１９、Ｐｔ－１９５的多核核磁共振。当ＳｎＣｌ２／ＤＣｌ溶液体系中加入Ｈ２ＰｔＣｌ６以后，出现了Ｓｎ（Ⅳ）和另外一种Ｓｎ（Ⅱ）的构型，Ｓｎ－１１９峰向高场位移，说明部分Ｓｎ（Ⅱ）被氧化成Ｓｎ（Ⅳ），Ｈ２ＰｔＣｌ６的量对这种氧化性影响较小。而Ｈ２ＰｔＣｌ６／Ｄ２Ｏ溶液体系中加入ＳｎＣｌ２以后部分Ｐｔ（Ⅳ）被还原成Ｐｔ（Ⅱ），随着ＳｎＣｌ２量的增加，Ｐｔ（Ⅱ）     

Application of Nafion／Cobalt Hexacyanoferrate Chemically Modified Electrodes for the Determination of Electroinactive Cations by Ion Chromatography

Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｏｎｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＩＣ)ｈａｓｂｅｅｎｒｅｃｏｇｎｉｚｅｄａｓａｕｓｅｆｕｌｍｅｔｈｏｄｆｏｒｔｈｅｓｅｐａｒａｔｉｏｎｏｆｉｎｏｒｇａｎｉｃａｎｉｏｎｓａｎｄｃａｔｉｏｎｓｓｉｎｃｅｉｔｓｉｎｔｒｏｄｕｃｔｉｏｎｂｙＳｍａｌｌｅｔａｌ .ｉｎ 1975 .1ＡｓｉｇｎｉｆｉｃａｎｔｔｒｅｎｄｉｎｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆＩＣｍｅｔｈｏｄｉｓｓｅａｒｃｈｆｏｒｓｅｎｓｉｔｉｖｅａｎｄｕｎｉｖｅｒｓａｌｄｅｔｅｃｔｉｏｎｍｅｔｈｏｄｓ .Ｔｈｅｍａｉｎｄｅｔ…     

Recovery of pyridine from aqueous solution by membrane pervaporation

Three different membranes, based on poly(dimethylsiloxane) (PDMS), cation-exchange material and poly(vinyl alcohol) (PVA) respectively, were tudied for the separation of pyridine-water mixtures by pervaporation. The PDMS membrane was preferentially permeable to pyridine and the other two were selective towards water. Three membranes showed different permeation performance, allowing the application of the technique to the separation of feeds of different composition. The temperature profile of the permeability suggests that it is possible to carry out the operation at an elevated temperature in order to achieve high productivity. A combination of the three types of membranes was designed for the production of anhydrous pyridine from dilute pyridine aqueous solution by pervaporation.     

α-Fe2O3纳米微粒/硬脂酸交替L-B膜的结构表征

We reported in this paper FTIR linear diehroic spectroscopy and anisotropic properties of the nanoparticulate α-Fe_2O_3-stearate alternating Langmuir-Blodgett films (Fe_2O_3-St LB films) a new inorganic-organic quantum superlattice system. A new method fitted to inorganic-organic alternating films is used to study the molecular orientation and discuss the order arrangement of the nanopartieles in the films. The the results show that a configuration of stearate ions bound to the surface of the nano-particles: COO~- group are spherically bound to the surface of the nanoparticles; the hydrocarbon chains are almost perpendicular (31°±5°) to the substrate (7 nm-Fe_2O_3-St LB films). The orientation of hydrocarbon chains and CH_2 scissors vibration show the existence of trans-zigzag planar structure for C—C broken bone of the hy7drocarbon chains, which is related to high-order structure of the alternate films.     

BEHAVIOR OF SUPPORTED NANO-COPPER CATALYST IN CO OXIDATION

IntroductionNanomaterialisanewkindofmaterialwithparticlesizebetWeenIurnand100urn.Becauseofthesmallparticlesizeandthelargespecificsufficearea,nanomaterialpossessesmanyparticularproperties,suchashighersufficeenergyandhighersurfaceactivity.t.[l]Thehigheracti…     

Aromatization of methane over different Mo-supported catalysts in the absence of oxygen

Both acidity and structure of the support are important factors in converting methane to aromatics. Lower SiO₂/Al₂O₃ ratio seems to favor the aromatization of methane over the Mo/HZSM-5 catalyst. When Pt is added as a modifier the activity of Mo/HZSM-5 catalyst will decrease slightly, but coke formation will enhanced.     

气相色谱法研究配位化合物的热稳定性——ⅩⅢ.普鲁士蓝化合物的热分解及其加氢反应研究

普鲁士蓝化合物的热分解过程,可分为三个阶段:(1)脱水;(2)Fe³⁺还原至Fe²⁺;(3)C≡N^-键的断裂。H₂气中的热分解由于发生了一系列的加氢反应,分解产物及所对应的分解温度都不同于He气中的情况,其产物的种类增加,C≡N^-键的断裂温度降低。普鲁士蓝化合物中,CN^-呈典型的双端基配位,可看作是一种双金属配位的活化模型,与CN^-呈单端基配位的K₃[Fe(CN)₆]相比,C≡N^-键的活化程度增加,不仅断裂温度降低,且能发生更深度的加氢反应。     

壳聚糖对鞣酸絮凝作用的研究

以壳聚糖为絮凝剂，采用絮凝法除去中药药液中的杂质。以鞣酸为研究对象，从鞣酸浓度，体系温度，ＰＨ絮凝剂用量粘均分子量等方面探讨其絮凝规律，用正交试验优化其絮凝条件，为实施中药药液的絮凝法精制工艺提供参考。     

Formation,growth mechanism and packing sequences of binary alloy cluster anions from laser ablation of mixtures of lead and transition metals

By using laser ablation of the mixtures of a transition metal (M: Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pd, Ag) plus lead, M/Pb binary cluster anions were observed except for Zn, and the number of transition metal atoms contained in the binary clusters is at most 4. This behavior is different from that reported previously for M/Ge binary clusters. The experiments indicate that it is also very difficult to form Al/Pb clusters. The distribution patterns of M/Pb binary alloy cluster anions are remarkably similar to those of pure Pb clusters, consistent with a formation mechanism in which transition metal atoms are sequentially attached to [M(x-1)Pb(y)](-) clusters and thus form [M(x)Pb(y)](-) clusters by a simple condensation process. As the number of transition metal atoms increases, the intensities of binary clusters gradually decrease. It is proposed that [MPb(4)](-) and [MPb(5)](-) cluster anions might be the unit building blocks of M/Pb binary cluster anions, and the layer packing sequences for magic clusters are predicted on this basis. The [M(x)Pb(y)](-) binary clusters containing 13 atoms (x + y = 13; x not equal 0) are proposed to have an icosahedral structure.     

Catalytic Oxidation of Dimethyl Ether to Dimethoxymethane over Cs Modified HaPW12O40/SiO2 Catalysts

The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.