关于有机化学课程中乙烯、乙炔球棍模型的一点探讨

乙烯、乙炔分子球棍模型在有机化学课程教学过程中广泛使用,但是目前广泛使用的乙烯、乙炔分子球棍模型容易引起学生的一些误会,建议在乙烯、乙炔分子球棍模型中,弧形弯曲连接杆表示π键,用直线连接杆表示δ键,这样既有效的区分出了π键、δ键类型的不同;通过弧形弯曲连接杆比直线连接杆长,也形象地表示出了π键没有δ键稳定,π键易断裂,发生加成反应这一实验事实。     

判断多原子共价分子内部结构的思路和方法

融合性地运用各种经典的分子结构理论,提出了判断多原子分子内中心原子轨道杂化方式、分子空间取向及分子内部价键结构(包括σ键、π键、大π键等的形成情况)的逻辑思路和操作方法,讨论了其中所蕴含和依据的原理。     

乙炔电还原制备乙烯的反应机理

选择钯电还原乙炔制备乙烯并通过气相色谱法对产品进行表征,利用第一性原理计算方法探讨乙炔在催化剂Pd (111)表面的吸附情况,采用循环伏安法研究钯电极在硫酸溶液中还原乙炔的电极过程,测定电极的稳态极化曲线并根据极化曲线推算Tafel斜率,重点结合表观传递系数及反应级数对拟定的乙炔电还原制备乙烯的反应机理进行验证。实验结果表明:乙炔分子在Pd (111)面上呈平行桥键构型时最稳定;钯电极在硫酸溶液中可将乙炔电还原为乙烯;得出了反应最可能的速率控制步骤。     

用电子密度拓扑方法分析乙烷、乙烯,乙炔以及乙烷的取代物中C-C键的递变规律

利用电子密度拓扑分析的方法对乙烷、乙烯、乙炔以及乙烷的卤代物和同系物中C-C键的性质的理论分析,研究其递变规律和递变原因。找到乙烯、乙炔分子的霄键键鞍点研究其递变规律和原因。     

乙烯和乙炔的亲电加成反应活性分析

本文通过对乙烯和乙炔的化学键构成、键能的比较 ,以及对乙烯和乙炔与卤化氢和卤素的亲电加成反应中间体物质的分析 ,说明乙烯的亲电加成反应活性大于乙炔的亲电加成反应活性。     

三卤化硼分子中的离域键对其性质的影响

从杂化轨道理论出发,探讨了三卤化硼分子（BX3,X=F,Cl,Br,I）中的σ共价键和离域大π键的形成,并用离域大π键解释了缺电子化合物三卤化硼的稳定性。用卤素的电负性及其三卤化硼的离域大π键这两个因素讨论了三卤化硼的Lewis酸性强弱顺序、水解及形成配合物的难易程度。     

基于芴衍生物的D-A化合物及其共聚物的研究进展

芴衍生物具有吸电子性,作为电子受体在D-A共聚体的研究中备受关注。在D-A共聚体中,π-电子供体和π-电子受体通过π键或σ键交替连接,其共平面的共轭结构有利于降低体系的能隙;以芴、芴酮、9-二氰基亚甲基芴衍生物为电子受体单元的推拉型(D-A型)化合物和共聚物,具有优异的光电性能、电子传输性能、较好的电子和空穴迁移率及在空气中极好的稳定性等。主要对基于芴、芴酮、9-二氰基亚甲基芴的D-A化合物及其D-A共聚物的最新研究进展做简要综述。     

可自修复型超分子聚合物研究进展

非共价键键和的超分子聚合物具有典型的可逆性,通过合适的刺激响应能够赋予聚合物材料一定的自修复性能。本文主要综述了非共价键(氢键、金属配位键、π-π相互作用等)键和的自修复超分子聚合物的研究进展。     

炭化学的新领域─富勒烯──Ⅰ．富勒烯分子的结构

以Ｃ（６０）为代表的富勒烯分子是一类由五元及六元碳环相互连接构成的封闭中空球状分子。分子中每个碳原子均与相邻另三个碳原子以σ键连接，所有碳原子各自贡献一个剩余的价电子形成离城球面大π键。富勒烯分子的发现给炭化学的发展开辟了新里程。     

炭化学的新领域—富勒烯：Ⅰ.富勒烯分子的结构

以Ｃ６０为代表的富勒烯分子是一类由五元及六元碳环相互连接构成的封闭中空球状分子，分子中每个碳原子均与相邻另三个碳原子以σ键连接，所有碳原子各自贡献一个剩余的价电子形成离域球面大π键。富勒烯分子的发现给炭化学的发展开辟了新里程。     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.