Pt/CeO2-ZrO2/Al2O3催化剂的光谱表征

利用拉曼光谱表征了不同方法添加ＣｅＯ２－ＺｒＯ２混合氧化物对Ｐｔ／Ａｌ２Ｏ３催化剂的影响,并采用了ＸＲＤ,Ｈ２化学吸附,ＢＥＴ表征了相应的分散度影响。结果表明：Ｃｅ、Ｚｒ、与金属Ｐｔ存在着强的相互作用,而ＣｅＯ２－ＺｒＯ２以盐的形式加入时,高度分散在Ａｌ２Ｏ３载体上,提高贵金属Ｐｔ的分散度,进而提高了反应的活性。     

Synthesis and Crystal Structure of [1‐(η5‐9‐Fluorenyl)‐2‐(η5‐1‐indenyl)ethane]hafnium Dimethyl

The synthesis and characterization of the unsymmetric hafnium dialkyl [1‐(η⁵‐9‐fluorenyl)‐2‐(η⁵‐1‐indenyl)ethane]HfCl₂ ( 2 ) and corresponding dimethyl complex [1‐(η⁵‐9‐fluorenyl)‐2‐(η⁵‐1‐indenyl)ethane]Hf(CH₃)₂ ( 3 ) is described. The dialkyl hafnocene ( 3 ) crystallizes in monoclinic space group P2₁/c (No. 14) with a = 9.458(8), b = 8.541(8), c = 23.733(11) Å, β = 93.16(5) deg., V = 1914(3) ų, Z = 4. Further on, complex 3 was activated with methylaluminiumoxane (MAO) and utilized as a catalyst in ethene polymerization.     

(VO)2P2O7催化剂上正丁烷选择氧化反应路径的原位瞬态DRIFTS研究

在钒磷复合氧化物(VO)2P2O7催化剂上,运用脉冲反应和反应物组成序贯切换的瞬态反应技术,对正丁烷和C4烯烃(1-丁烯、1,3-丁二烯)选择氧化制顺酐过程进行了瞬态原位DRIFTS研究,考察了正丁烷选择氧化反应体系的反应网络和基元过程序列结构。获得了含羰基的非环状饱和与不饱和物种都可能是正丁烷选择氧化制顺酐过程的中间物的证据,在1-丁烯和1,3-丁二烯的原位瞬态DRIFTS研究中检测到了呋喃。推断中间物呋喃在生成顺酐前可能经历了开环形成含羰基的非环状不饱和物种的过程。基于实验结果及与文献的比较,提出了正丁烷在VPO催化剂上选择氧化可能的反应路径。     

烯烃聚合催化剂和聚合反应

简要叙述了传统齐格勒－－纳塔催化剂的发展和演变,介绍了茂金属催化睡聚烯烃工业的新发展,并对新一代后过渡金属烯烃聚合催化剂的研究进展作了综合评述。     

分子筛负载催化剂的烯烃配位聚合反应

分子筛是由TO4(T=Al,Si或P,少数情况下是B,Ga,Be等其它原子)四面体之间通过共享顶点而形成的三维四连接骨架.烯烃配位聚合反应是一类重要的高分子化学反应,将烯烃配位聚合催化剂负载于不同结构与孔径的分子筛后,分子筛不仅能起载体的作用,调变聚合反应的动力学行为,改善聚烯烃的形态;其纳米孔道更是烯烃聚合的反应器,可以调节所得聚烯烃的分子量及其分布、加工流变性能、立构规整性和共聚物中共单体的含量.本文着重论述了分子筛负载催化剂的烯烃配位聚合反应新进展.     

Preparation and characterization of rice husk/ferrite composites

<正>A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere.The rice husk substrate consists of porous activated carbon and silica,where spinel ferrite particles with average diameter of 59 nm are distributed.The surface area of the composite is greater than 170 m~2 g~(-1) and the bulk density is less than 0.6 g cm~(-3).Inert atmosphere is indispensable for the synthesis of pure ferrite composites,while different preparation temperatures of above 600℃result in composites with similar structures and morphologies.Due to the presence of ferrite particles,this novel composite shows enhanced adsorption ability for acid orangeⅡ.     

Thermal, catalytic and antimicrobial aspects of polychelates of phenolic resin with lanthanides (III)

The polymeric ligand (resin) was synthesized by condensation of 2-hydroxy-4-ethoxybenzophenone with 1,2-propylene glycol in presence of polyphosphoric acid as a catalyst at 150 °C for 10 h. The resin and its polychelates were characterized on the basis of elemental analyses, electronic spectra, magnetic susceptibilities, Fourier transform infrared spectroscopy (FTIR), NMR and thermogravimetric analyses. Morphological Study of resin and polychelates were carried out by scanning electron microscope (SEM). The number average molecular weight was determined using vapor pressure osmometry (VPO) method. Antimicrobial activity of polychelates and catalytic activity of selected polychelates in organic synthesis have been studied. It was observed that, polychelates were found efficient catalysts and effective antimicrobial agents.     

Coral-shaped and core-shell structure copolyethylene nanocomposites particles prepared by in situ coordination polymerization

The example of the preparation of nano- and micro-scaled, coral-shaped and core-shell topological morphology of copolyethylene particles promoted by the novel heterogeneous non-metallocene catalyst(m-CH3 Ph O)Ti Cl3/carbon nanotubes(CNTs) was reported. Mass fraction of titanium component of the catalyst was 4.0 wt% determined by ICP analysis. The catalyst system can effectively catalyze polymerization of ethylene and copolymerization of ethylene with 1-hexene. Morphological examination of the obtained polymer particles was carried out by scanning electron microscope(SEM) and high resolution transmission electron microscope(HR-TEM) technique. The results revealed that the morphology of the nascent copolyethylene particles looked like coral shape with size in micro-scaled and featured the core-shell structure consisting of CNTs as the core and copolyethylene as the shell.     

New Recoverable Organoselenium Catalyst for Hydroperoxide Oxidation of Organic Substrates

New benzisoselenazol-3(2H)-one covalently bounded to a silica support was synthesized and characterized. It was used as an effective, selective, and easy-to-regenerate catalyst for t-BuOOH and H₂O₂ oxidation of alkyl arenes to alkyl aryl ketones, aromatic aldehydes to arene carboxylic acids, and sulfoxides and/or sulfones.     

Recent Progress in Commercial and Novel Catalysts for Catalytic Dehydrogenation of Light Alkanes

Catalytic dehydrogenation of light alkanes can effectively produce olefins and hydrogen. Even though Pt and CrO_x‐based catalysts are widely applied in industry, research to improve the activity and stability of these catalysts continued. This review summarizes important achievements obtained in recent years, focusing on the development of supports, promoters and preparation methods of Pt and CrO_x‐based catalysts, which mainly aimed to improve the dispersion of the active species and to enhance coke resistance. Furthermore, the high cost of Pt‐based catalysts and environmental problems encountered with CrO_x‐based catalysts have spurred the development of alternative catalysts. The dehydrogenation performances and characteristics of promising alternative VO_x‐, modified Ni‐ and Sn‐based catalysts are also reviewed. Comparison with the catalytic reforming process of naphtha further probes the necessity of catalyst acidity in these two different processes. The choice of the dehydrogenation reactor is discussed, and future perspectives and research directions are indicated.