函数内逆P-集合在QSPR研究中的应用

将函数内逆P-集合理论引入QSPR研究中,利用函数内逆P-集合的动态特征筛选预测链烷烃标准生成焓的属性参数, 运用函数内逆P-集合的规律特征给出不同类型的预测链烷烃标准生成焓的规律函数。成功地预测了41种链烷烃的标准生成焓。结果表明,属性参数与链烷烃的标准生成焓高度相关,复相关系数达到或超过0.998。     

用相互作用势指数估算单取代烷烃生成焓

基于直链烷烃生成焓的实验值提出16种取代基X(OH、SH、NH₂、Br、Cl、I、NO₂、CN、CHO、COOH、CH₃、CH=CH₂、C≡CH、Ph、COCH₃、COOCH₃)的相互作用势指数IPI(X). 用IPI(X)和极化效应指数建立模型,对单取代烷烃RX(包括含支链的化合物)的生成焓进行估算,所得回归方程有良好的相关性,该模型既考虑了基团R和X的贡献,又考虑了R与X相互作用的贡献. 并采用留一法对其稳定性和预测能力进行验证.     

正构烷的热压力系数及内压的预测

本文通过修正的van der WaaIs模型,建立了一个能够预测C_1—C_(36)正构烷在各种温度下热压力系数及内压的方法。对20℃下正构烷的热压力系数检验表明,预测值与实验值的最大误差约为±0.8%。与一般小分子液体不同,正构烷的B/A~2值不是一个常数,在C_9处有一转折。当碳数>9时,B/A~2值随碳链的增长而明显减少。     

Activation of ethane in the metathesis reaction on silica-supported tantalum hydride: a quantum-chemical study

The structures of the (H₄Si₂O₅)O₂TaR and (H₄Si₂O₅)O₂TaRH₂ clusters (R = H, Me, or Et), which model the main structural units of the catalytic cycle of the ethane metathesis on silica-supported tantalum hydride, were studied using the density functional theory at the B3LYP level. Even at high temperatures, activation of ethane cannot proceed via a two-step mechanism involving the oxidative addition of ethane and reductive elimination of hydrogen to form pentavalent tantalum compounds.     

Effect of Na+, Mg2+, and Zn2+ chlorides on the structural and thermodynamic properties of water/n-heptane interfaces

The effect on the structural and thermodynamic properties in water/n-heptane interfaces on addition of NaCl, MgCl(2), and ZnCl(2) has been examined through five independent 100-ns molecular dynamics simulations. Results indicate that the interfacial thickness within the framework of the capillary-wave model decreases on addition of electrolytes in the order Na(+) < Mg(2+) < Zn(2+), whereas the interfacial tension increases in the same order. Ionic density profiles and self-diffusion coefficients are strongly influenced by the strength of the first hydration shell, which varies in the order Na(+) < Mg(2+) < Zn(2+). On the other hand, the Cl(-) behavior, that is, diffusion and solvation sphere, is influenced by its counterion. Accordingly, cations are strongly expelled from the interface, which is especially remarkable for the small divalent cations. This fact alters the water geometry near the interface and in a lesser extent n-heptane order and number of hydrogen bonds per water molecule close to the interface.     

几种新的结构参数用于烷烃熔沸点的研究

用矩阵的方法定义了结构参数fi1 、fi2 、fi3 ,并建立了有机化合物的连接性指数 mL ,mL =∑(fi·fj·fk… ) 0 .5.该指数考虑了分子中原子之间的联结关系 ,顶点原子的特征和相邻原子的键合情况 .用 mL对 15个烷烃分子的熔沸点进行相关性研究比较 ,相关系数R均超过 0 .99.     

仲烷基磺酸钠(SAS)开发应用前景

介绍了仲烷基磺酸钠在日用化工、聚氯乙烯、橡胶、纺织、石油等行业中的应用前景。