Selective Oxidation of Isobutane to Methacrylic Acid over Supported V-Mo-P Based Composite Oxide Catalysts

Heteropolyacid, the most popular catalyst for the direct oxidation of isobutane, exhibits high catalytic activity, poor thermal stability and a short lifetime. Therefore, the catalyst requires further research to improve its performance. Catalysts composed of mixed oxides (V2O5, P2O5, or MoO3) supported on silica were prepared by the sol-gel method to catalyze the reaction. Results of XRD, IR, and BET corroborated that the mixed oxides were dispersed homogeneously on the surface of support. The activity of lattice oxygen in the catalysts was studied by TPR, and the chemisorption property of isobutane on the surface of the catalysts was investigated by the TPD method. H2-TPR of the catalysts revealed that the lattice oxygen of the vanadium-based catalysts is more active than that of the molybdenum-based catalysts. The redox property of V or Mo species is slightly affected by other compositions of the series catalysts. The TPD curves illustrate that there are two kinds of adsorptive species of isobutane on     

关于单取代烯类聚合物中键接异构序列的研究

本文研究了α-取代烯类聚合反应的键接异构问题。通过严格求解动力学微分方程组,推导出聚合物的头-尾序列分布函数以及各种二元组和三元组浓度的表达式,并将这些结构参数与聚合条件及反应时间或单体转化率联系起来,因而可根据反应条件预测聚合物的微观结构。当反应时间足够长时,文中的公式可简化为前人用几率法得到的结果。     

Deactivation Mechanism for COS Hydrolysis over TGH Catalyst——FT-IR Study of the Adsorption Behavior of COS,O_2 and H_2S

The adsorptions of COS, H2S and O2 were investigated over the TGH catalyst in this paper. It was found that the numbers of basic centers and basic intensities were reduced over the deactivated TGH catalyst. The PT-IR results of COS+H2S+O2 co-adsorption on the TGH catalyst show that the main causes of catalyst deactivation is the formation of element sulfur and trace sulfate.     

以食糖热裂解碳作为电极的双电层电容器的性能

近年来, 随着各种电子仪器的飞速发展, 对可充电的脉冲功率电源和备用电源的研究越来越引起人们的高度重视. 同时, 由于空气中汽车尾气浓度的增加使环境污染日趋严重, 因此对电动车辆的应用要求也就越来越紧迫. 双电层电容器(EDLC)的容量可以达到或接近Ni-Cd电池的容量,它和蓄电池组合应用, 两种器件能取长补短, 可达到最佳匹配状态, 并成为电动车辆理想的电源系统[1,2].对EDLC影响最大的是电极材料, 现在主要使用具有电子传导性和大比表面积的活性炭. 考虑到生产技术和原料如PVDC、聚丙烯腈、 酚醛树脂 [3~9]等聚合物来源问题, 我们尝试了一种制备活性炭的新前驱物—食糖, 在不同条件下进行热裂解, 并通过改变活化方法, 制备了各种类型的活性炭, 初步探讨了制备活性炭的方法及其作为双电层电容器电极的性能.     

对固体圆二色光谱测试方法的再认识——兼谈“浓度效应”

对近期发展的固体圆二色(CD)光谱测试方法进行了概述、评价和比较, 着重探讨了“浓度效应”的存在使固体CD光谱失真的原因. 通过对本课题组和其他作者已报道的四种化合物的固体CD谱再测试的反思, 强调了依手性化合物的手性光谱学性质不同, 根据浓度梯度实验选择其合适测试浓度的必要性. 对固有手性的阻转异构化合物(S)-1,1'-联二萘酚(S-BINOL)进行了成膜法固体CD谱浓度梯度测试, 发现所得固体薄膜CD谱中也存在着“浓度效应”     

对固体圆二色光谱测试方法的再认识——兼谈“浓度效应”

对近期发展的固体圆二色(CD)光谱测试方法进行了概述、评价和比较, 着重探讨了“浓度效应”的存在使固体CD光谱失真的原因. 通过对本课题组和其他作者已报道的四种化合物的固体CD谱再测试的反思, 强调了依手性化合物的手性光谱学性质不同, 根据浓度梯度实验选择其合适测试浓度的必要性. 对固有手性的阻转异构化合物(S)-1,1'-联二萘酚(S-BINOL)进行了成膜法固体CD谱浓度梯度测试, 发现所得固体薄膜CD谱中也存在着“浓度效应”     

对固体圆二色光谱测试方法的再认识——兼谈“浓度效应”

对近期发展的固体圆二色(CD)光谱测试方法进行了概述、评价和比较, 着重探讨了“浓度效应”的存在使固体CD光谱失真的原因. 通过对本课题组和其他作者已报道的四种化合物的固体CD谱再测试的反思, 强调了依手性化合物的手性光谱学性质不同, 根据浓度梯度实验选择其合适测试浓度的必要性. 对固有手性的阻转异构化合物(S)-1,1'-联二萘酚(S-BINOL)进行了成膜法固体CD谱浓度梯度测试, 发现所得固体薄膜CD谱中也存在着“浓度效应”     

对固体圆二色光谱测试方法的再认识——兼谈“浓度效应”

对近期发展的固体圆二色(CD)光谱测试方法进行了概述、评价和比较, 着重探讨了“浓度效应”的存在使固体CD光谱失真的原因. 通过对本课题组和其他作者已报道的四种化合物的固体CD谱再测试的反思, 强调了依手性化合物的手性光谱学性质不同, 根据浓度梯度实验选择其合适测试浓度的必要性. 对固有手性的阻转异构化合物(S)-1,1'-联二萘酚(S-BINOL)进行了成膜法固体CD谱浓度梯度测试, 发现所得固体薄膜CD谱中也存在着“浓度效应”     

Synthesis and Crystal Structure of Dissymmetrical Double Schiff Base Cu（Ⅱ） Homobinuclear and Cu（Ⅱ）-Mg（Ⅱ）-Cu（Ⅱ） Heterotrinuclear Complexes

Homobinuclear complex （HCuL）2 （1） （H3L： N-3-carboxylsalicylidene-N＇-salicylaldehyde-1,2-diaminoethane） was obtained from self-organization of the reported complex HCuL, and its crystal structure was determined through X-ray diffraction at room temperature. The crystal of complex 1 belongs to monolinic system, the space group Cc, a=2.5326（5） nm, b=0.88861（18） nm, c=1.3738（3） nm, β=96.95（3）°, Z=4, R1=0.0520, wR2=0.1185. （HCuL）2 is a dimeric molecule and has extended phenolic oxygen-bridged structure. In addition, using mononuclear complex HCuL as building blocks, Cu（Ⅱ）-Mg（Ⅱ）-Cu（Ⅱ） heterotrinuclear complex 2 was synthesized, and its crystal structure also has been determined by X-ray analysis. The crystal of complex 2 is of monoclinic system, space group Pc, a=1.1816（2） nm, b=1.5599（3） nm, c=1.9642 （4） nm, β=98.22°, Z=2, R1=0.0701, wR2=0.1498. Each dissymmetricai cell unit of complex 2 contains two heterotrinucler neutral molecules： {[CuL（H2O）]Mg[CuL（CH3OH）]} and {[CuL]Mg[CuL（H2O）]}.     

Preparation of AgBiVMoO/γ-Al_2O_3 Catalysts for the Partial Oxidation of Propane to Acrylic Acid by the Mixed Sol Method

A novel mixed sol method was developed for the preparation of supported catalysts. Analyses by means of XRD and BET show that a 40%AgBiVMoO/γ-Al2O3 catalyst prepared by this method possessed high specific surface area and high dispersion of the active phase. As a result, high acrylic acid selectivity of 8.5% was obtained when the catalyst was used in the reaction of propane partial oxidation to acrylic acid in a fixed-bed reactor.