The matching of structural elements in reactions for evaluating stabilization energies for benzene and monosilabenzene

Using the 6-31G^* basis set the stabilization energy for monosilabenzene has been calculated as E _T for the homodesmotic reactions in which (i) ethylene is the other reactant with trans 1,3-butadiene and trans 2-sila-1,3-butadiene as the products, and (ii) trans 1,3-butadiene is the other reactant with trans 1,3,5-hexatriene and trans 3-sila-1,3,5-hexatriene as the products. The values are 17.2 and 17.6 kcal mol^–1 respectively, compared to 24.8 and 23.5 kcal mol^–1 respectively for the corresponding reactions of benzene. The difference is E _T for the interchange of =SiH- and =CH- groups between the aromatic and aliphatic structural environments, and is thus more informative than the quotient. The extent of the matching of structural elements in these reactions, and in the benzene reactions using longer chain polyenes, is assessed in terms of the structural environment about each heavy atom in its entirety — namely the nearest neighbor atoms (NN), the next nearest neighbor atoms (NNN), and the more distant atoms (NNNN and NNNNN). Matching by number alone is designated isoplesiotic, and if by both number and kind, homoplesiotic.     

甲烷直接芳构化反应的研究Ⅰ．负载Mo基催化剂在无氧条件下的催化性能

研究了催化剂制备方法、Ｍｏ含量、预处理条件和反应条件对在无氧条件下ＨＺＳＭ－５负载的Ｍｏ基催化剂上甲烷直接芳构化反应的影响，及积炭和烧炭再生对催化剂性能的影响．发现Ｍｏ含量为３．５～４％时催化剂活性最高，生成苯的速率高达１．２×１０－３ｍｏｌ·ｇ－１·ｓ－１．降低空速和提高反应温度均有利于甲烷的直接芳构化．随着反应的进行，乙烯的选择性不断提高，苯的选择性则不断降低．ＸＰＳ结果表明，反应后催化剂表面积炭，且研磨法制备的催化剂中Ｍｏ６＋被还原成不具活性的金属态Ｍｏ０．卡宾中间体（Ｍｏ＝ＣＨ２）可能是甲烷芳构化反应的起始物．     

芳香化合物STM研究的进展

本文系统介绍了用STM技术研究苯、萘和蒽等芳香化合物的诸多成果，表明分子间相互作用、分子与基底间相互作用等对该类化合物吸附结构的影响，以及溶液中分子的结构、结构转化及表面反应与电极电位的关系，阐明了在原子分子惊讶上研究芳香化合物的重要性及发展趋势。     

气固相类质同晶取代合成含钛沸石

气固相类质同晶取代合成含钛沸石陈国辉，夏清华，高滋（复旦大学化学系，上海２００４３３）关键词类质同晶取代，含钛沸石，苯酚，双氧水，羟化反应具有ＭＦＩ结构的钛硅沸石ＴＳ－１是一种新发现的选择氧化催化剂，对芳烃及其它不饱和烃与Ｈ２Ｏ２的氧化反应有很高的催...     

Benzene charge exchange at atmospheric pressure for low-level detection of pollutants in ambient air

Charge exchange using the benzene molecular ion in a corona discharge atmospheric pressure ionization source is shown to be extremely sensitive for detecting low proton affinity compounds in air. Experiments performed on an Extrel API tandem mass spectrometric system indicated a limit of detection of 12.7 ppt for the detection of 2-chloroethyl ethyl sulfide in air.     

Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu_4FeAlCO_3

Phenol hydroxylation is an industrially important reaction, whose main products are catechol and hy-droquinone being diverse applications which are im-portant intermediates for perfumes, drugs, and phar-maceuticals and so on[1]. The processes using H2O2 a…     

Fe（Ⅲ）APO分子筛在芳香族化合物氧化反应中的催化活性

 Fe取代系列磷酸铝分子筛（FeAlPO4－5，FeAlPO4－11和FeVPI－5）在催化氧化芳香族化合物反应（如苯酚和苯的羟化、苯乙烯的环氧化以及萘酚的氧化）中具有很高的活性．系统研究的数据显示，在苯酚和苯的羟化及苯乙烯的环氧化反应中，FeAlPO4－5及FeAlPO4－11的活性与TS－1催化剂相近；在大分子萘酚的氧化反应中，FeVPI－5具有较高的活性，而小孔的TS－1则没有活性．比较不同催化剂的活性结果表明，骨架中的Fe（Ⅲ）是催化剂的活性中心．