烷基苯生产中循环烷烃的液固吸附色谱预分离和气相色谱/质谱分析

 利用 10 0目～ 2 0 0目的硅胶 ,选择正戊烷和二氯甲烷作为洗脱剂 ,采用吸附色谱法将烷基苯生产中的循环烷烃分离为饱和烃 (烷烃 +环烷烃 )及芳烃两部分。然后将饱和烃及芳烃分别进行色谱 /质谱 (GC/MS)联用分析 ,得到了有关循环烷烃构成的定性定量结果。定性结果如实地反映出烷基苯生产中的副反应产物 ,可直接用于指导生产。从定量结果可以看出 ,经过硅胶吸附分离后 ,试样中含量要求很低的芳烃被浓缩 ,提高了分析的准确度和灵敏度 ,可以检测出循环烷烃中含量很低的物质 ,为全面分析样品组成提供了有力的证据。     

Excess enthalpies of binary mixtures of 2-, 3-, 4-picoline+n-alkane (C6H14-C10H22) at 298.15 K. Comparison with theory

The molar excess enthalpies measured for binary mixtures of 2-, 3-, 4-picoline +n-alkane (C₆H₁₄-C₁₀H₂₂) at 298.15 K have been compared with the Prigogine-Flory-Patterson theory and the Extended Real Associated Solution model estimations.

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Zusammenfassung Die bei 298.15 K gemessenen molaren Zusatzenthalpien binärer Mischungen aus 2-,3-,4-Picolin und einemn-Alkan (C₆H₁₄-C₁₀H₂₂) wurden mit den nach der Prigonine-Flory-Patterson-Theorie und den nach dem erweiterten Modell real assoziierter Lösungen (ERAS) berechneten Weiten verglichen.

     

Vapor-liquid equilibria forn-tetradecane-benzene mixtures at 25 and 50°C

Vapor pressures for the benzene+n-tetradecane system have been measured using a static apparatus. The excess Gibbs free energy was calculated using a modified Barker method and a Pade approximant equation. The selection of the most adequate approximation is discussed. Results are compared with those corresponding to other thermodynamic properties. The activity coefficient of benzene at infinite dilution calculated from these data agrees well with the value obtained from the literature.     

环糊精与乙烯和三十烷醇包结物的研究

本文报道在常压下制备了α-环糊精-乙烯包结物的微细晶体,和环糊精与三十烷醇的溶胶与粉末包结物,以增加长链烷基醇的溶解度。其溶胶在室温下放置半年不凝聚。还用X-射线粉未衍射法、1~H核磁共振及差热-热重分析等方法研究了包结物的形成。     

Experimental and Theoretical Study of NiII- and PdII-Promoted Double Geminal C(sp3)−H Bond Activation Providing Facile Access to NHC Pincer Complexes: Isolated Intermediates and Mechanism

We report the first examples of metal-promoted double geminal activation of C(sp³)−H bonds of the N−CH₂−N moiety in an imidazole-type heterocycle, leading to nickel and palladium N-heterocyclic carbene complexes under mild conditions. Reaction of the new electron-rich diphosphine 1,3-bis((di-tert-butylphosphaneyl)methyl)-2,3-dihydro-1H-benzo[d]imidazole ( 1 ) with [PdCl₂(cod)] occurred in a stepwise fashion, first by single C−H bond activation yielding the alkyl pincer complex [PdCl(PC ^HP)] ( 3 ) with two trans phosphane donors and a covalent Pd−C bond. Activation of the C−H bond of the resulting α-methine C H−M group occurred subsequently when 3 was treated with HCl to yield the NHC pincer complex [PdCl(PC^NHCP)]Cl ( 2 ). Treatment of 1 with [NiBr₂(dme)] also afforded a NHC pincer complex, [NiBr(PC^NHCP)]Br ( 6 ), but the reactions leading to the double geminal C−H bond activation of the N−CH₂−N group were too fast to allow identification or isolation of an intermediate analogous to 3 . The determination of six crystal structures, the isolation of reaction intermediates and DFT calculations provided the basis for suggesting the mechanism of the stepwise transformation of a N−CH₂−N moiety in the N−C^NHC−N unit of NHC pincer complexes and explain the key differences observed between the Pd and Ni chemistries.     

The effect of the conditions of the photocatalytic carbonylation of pentane catalyzed by the Rh2Cl2(CO)4-PMe3 system on the yield of C6-aldehyde

The yield of C₆-aldehyde in the photocatalytic system Rh₂Cl₂(CO)₄-PMe₃ passes through a maximum as the CO pressure and PMe₃ concentration increase. The increase in the yield of aldehydes with increasing CO pressure is related to the increase in the carbonylation rate and to the retardation of the photodecomposition of the aldehydes. The rate of the photocatalytic carbonylation of pentane in this system is 20 times higher than in the presence of RhCl(PMe₃)₂(CO).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1013–1015, June, 1994.     

改进的连接性指数用于链烷烃热力学性质与沸点研究

基于邻接矩阵和原子特征值qi，建立邻接指数^mQ,用^0Qr,^1Q与85种链烷烃的标准生成焓、标准生成自由能、标准熵和沸点关联，相关系数均在0.99以上，属于良好模型，与Randic指数的^mX比较，^mQ具有良好的性质相关性。     

Excess enthalpies of mixtures containing n-heptane,methanol and methyl tert-butyl ether (MTBE)

Molar excess enthalpies H ^E have been measured for the binary mixtures MTBE+methanol, MTBE+n-heptane and methanol+n-heptane using a quasi-isothermal flow calorimeter. The measurements have been performed at atmospheric pressure and at 25 and 40°C for all the mixtures and for MTBE+methanol also at 50°C. The experimental results for MTBE methanol and MTBE+n-heptane are compared with those calculated using the NRTL equation.Communicated at the Festsymposium celebrating Dr. Henry V. Kehiaian's 60^th birthday, Clermont-Ferrand, France, 17–18 May 1990     

Molecular shape and orientational order. Effects in the energy of cavity formation in liquids

A recently proposed method for calculating the energy of cavity formation in liquids is presented in which the cavity formation process is described as work against the surface forces of the solvent, at the microscopic scale. The energy involved in the cavity formation process is, on the other hand, viewed as a strictly interaction potential energy and the reference cavity, which has the size and the shape of the space occupied by each molecule in the liquid, is considered as having short-range orientational order characteristic of the pure liquid. The method is successfully applied to binary alkane mixtures at infinite dilution whose components have different chemical structure (linear, cyclic and branched alkanes). The importance of the changes in the molecular order of the solute and the solvent occuring in the mixing process is emphasized.     

不同温度予处理Pt／Al2O3催化剂对其表面结构和反应性能的影响

由于链烷烃在Pt/Al_2O_3催化剂上反应的复杂性,许多学者为了深入研究包括催化剂制备、反应机理等的内在规律,进行了大量的研究,取得了许多重要成果。近几年来,较多的工作着重从分散态金属的几何和电子因素,及金属同担体的相互作用进行考察,在催化剂制备方面,更多的注意添加第2、第3组元、杂质或毒物等对金属催化性能的调变作用,以期开发出高选选择性催化剂。而对不同气氛、不同还原温度下