Diffusion Mechanisms of Zeolite Catalysts

The diffusion mechanisms within zeolite catalysts, such as resistance to diffusion at pore mouths, configurational diffusion, adsorption-controlled diffusion, influence of co-existing molecules and pore blocking, were overviewed. Two kinds of diffusivities, the intracrystalline diffusivity and the effective diffusivity, were discussed separately to clarify the diffusion mechanism.     

烯烃不对称双羟化及其反应机理的研究进展

本文综述了近年来四氧化锇催化烯烃不对称双羟化及其反应机理的研究进展。Sharpless等对烯烃双羟化机理的透彻研究导致了不对称双羟化方法的优化。     

Hydrogen elimination in cyclopentadienylnickel compounds as a route to organonickel and organic compounds

Reactions of -, β- and γ-hydrogen elimination in cyclopentadienylnickel compounds formed in the reactions of nickelocene with lithium or magnesium compounds are discussed. Elimination of -hydrogen from CpNiR where R is CH₃, CH₂C(CH₃)₃, CH₂Si(CH₃)₃, CH₂Ph or CH=C(CH₃)₂ leads to the formation of trinickel clusters (CpNi)₃CR′, bis(cyclopentadienyl)(μ-cyclopentadiene)dinickel and (η⁵-cyclopentadienyl)(η³-cyclopenteny)nickel. β-hydrogen and γ-hydrogen elimination in vinylnickel compounds not possesing -hydrogen have been studied. Elimination and transfer of hydrogen forms (η³-allyl)(η⁵-cyclopentadienyl)nickel compounds. The mechanisms of these reactions are discussed.     

合成气在Rh（111）上转化为乙醇的机理的键级守恒研究

Rh上乙醇的生成机理,目前主要有两类.一是Ichikawa等为代表提出的“CO解离—CH_x(x=2或3)—乙酰基—乙醇”机理;另一是蔡启瑞等的“CO缔合—甲酰基(金属氧卡宾)—卡宾—乙烯酮—乙酰基—乙醇”机理.本文用Shustorovich的键级守恒—Morse势(BOC-MP)法对其进行了研究     

Possible Mechanisms of Intercalation

Recent knowledge of the kinetics and intercalation mechanisms are summarized and accompanied by examples of intercalation reactions of water and ethanol into anhydrous vanadyl phosphate and redox intercalation of alkali metal cations into vanadyl phosphate dihydrate. Three possible mechanisms of intercalation are presented which are based on: (i) a concept of exfoliation of layers; (ii) the formation of stages and randomly stacked layers; (iii) co-existence of intercalated and non-intercalated parts of crystals of the host separated by an advancing phase boundary. The corresponding kinetic curves are ascribed to mechanisms (ii) and (iii).     

Pd-SiW12/SiO2催化剂上乙烯直接氧化制乙酸的反应机理

 利用积分反应器和微分反应器对Pd－SiW12／SiO2催化剂上乙烯直接氧化生成乙酸的反应机理进行了探讨．乙烯在积分反应中氧化的主要产物为乙酸（选择性为77．6％），很少生成乙醛（选择性仅为8．1％）；而在微分反应中氧化的主要产物是乙醛（选择性为98．4％）．在微分反应中分别以乙醛和乙醇为主反应物时，乙醛氧化完全生成乙酸，选择性为100％，而乙醇氧化生成乙酸的选择性低于0．15％．可以认为，在Pd－SiW12／SiO2催化剂上，水蒸气存在下乙烯主要经由中间物乙醛而生成乙酸．通过对含有不同组分和不同还原条件处理的催化剂活性的比较，认为目的反应主要发生在Pd与SiW12相互接触的部位，催化剂中的Pd0是活性Pd物种的主要形态．     

A quantitative evaluation of the electrostatic theory for ion pair chromatography

Summary A quantitative model for ion pair chromatography based on the electrostatic theory is described. The model is based on the solution of the linearised Poisson-Boltzmann equation in a cylinder. The obtained equations are compared with experimental data from a number of different systems. The agreement between theory and experiments is satisfactorily. Systematic deviations due to the use of the linearised equation and ion correlation effects are discussed.     

3，9－二羟乙基－3＇，9＇－二苯甲基－1，5，7，11－四氧杂螺环［5，5］十一烷的合成和聚合反应

从两二酸二乙酯、氯乙酸乙酯和氯苄出发，经ＬｉＡｌＨ４还原，合成新的二元醇，进而合成新的螺环化合物：３，９－二羟乙基－３＇，９＇－二苯甲基－１，５，７，１１－四氧杂螺［５，５］十一烷．该化合物的结构由它的氢和碳－１３核磁共振谱、红外光谱和元素分析得到证明．该单体在三氟化硼乙醚络合物的作用下进行开环聚合反应．由于环上四个取代基的稳定作用，聚合物的收率比较低（产率１０％左右）．通过对聚合物的结构分析，提出了这一单体的阳离子开环聚合反应机理．对随聚合温度升高，聚合物中酯基／苯基的克分子比降低，以及本体聚合时得到交联聚合物等一系列现象作了探讨．     

羧酸铜催化反应的研究——Ⅰ.羧酸铜催化醛肟转变为睛

本文报道了在多种羧酸铜催化下,醛肟在含有氰基的溶剂中(如CH_3CN、CH_3OCH_2CH_2CN等),均可脱水转变成相应的腈。反应条件温和,产率较高。具有不同空间和电性效应取代基的羧酸铜对反应的产率影响不大。实验中还发现溶剂乙腈参与了上述反应。