Microcalorimetric determination of enthalpies of solution of methyl alkanes in glacial acetic acid

An empirical equation H _{s, m}=0.84n gives the enthalpy of solution of 30 branched, linear and cyclic alkanes in glacial acetic acid. The parametern is an effective carbon number which expresses the number of carbon atoms in the longest chain plus one half of the pendant methyl groups.     

Ethane hydrogenolysis on silica-supported tantalum hydride. Quantum-chemical study

The structures of the (H₄Si₂O₅)O₂Ta(R, RR"R, RR) clusters (R, R", R = H, Me, Et, Pr; R = CH₂), which model the basic structural units of the catalytic cycle of ethane hydrogenolysis on silica-supported tantalum hydride, were studied by the density functional theory (B3LYP) and the perturbation theory (MP2). The possible structure of active sites was proposed based on comparison of experimental results with calculated data. Ethane hydrogenolysis and metathesis proceed by a mechanism involving the formation of ethylene -complexes and carbenium derivatives of tantalum as intermediates.     

Studies of Synthesis and Interfacial Properties of Sodium Branched‐Alkylbenzenesulfonates

Two sodium branched‐alkylbenzensulfonates with additional alkyl substituents were synthesized through a series of reactions. The interfacial tension of these alkylbenzenesulfonates between 1.0% NaCl solution and six n‐alkanes were measured. From the data of measurements the following values were calculated: critical micelle concentration (cmc), the interfacial tension at the cmc (γ_cmc), interfacial excess concentration at the cmc (Γ_m), area per molecule at the cmc (A_m). There were a minimum γ_cmc and a maximum Γ_m appeared for the same n‐alkane with increasing the hydrocarbon chain length of the oil. These indicated that the hydrocarbon chain length of oil have the important effect on adsorption and interfacial tension.     

Ruthenium(II) complexes of hybrid 8‐hydroxyquinoline–thiosemicarbazone ligands: synthesis,characterization and catalytic applications

A series of new hexa‐coordinated ruthenium(II) hydroxyquinoline–thiosemicarbazone complexes of the type [Ru(CO)(EPh₃)(B)(L)] (E = P or As; B = PPh₃, AsPh₃ or Py; L = hydroxyquinoline–thiosemicarbazone) were synthesized by reacting ruthenium precursor complexes [RuHCl(CO)(EPh₃)₂(B)] (E = P or As; B = PPh₃, AsPh₃ or Py) with hydroxyquinoline–thiosemicarbazone ligands in ethanol. The new complexes were characterized by analytical and spectroscopic (FT‐IR, UV–visible, NMR (¹H, ¹³C and ³¹P) and fast atom bombardment (FAB)–mass spectrometric methods. Based on the spectral results, an octahedral geometry was assigned for all the complexes. The new complexes showed good catalytic activity for the conversion of aldehydes to amides in the presence of hydroxylamine hydrochloride–sodium bicarbonate and for the oxidation of alkanes into their corresponding alcohols and ketones in the presence of m‐chloroperbenzoic acid. The complexes also catalyzed the N‐alkylation of benzylamine in the presence of KOtBu in alcohol medium. Copyright © 2013 John Wiley & Sons, Ltd.     

从“认识甲烷”到“认识有机化合物”——解析人教版高中化学教材中有机物的通性和烷烃

烷烃是衍生其他有机物的母体和碳骨架基础,烃基的性质决定了有机物的通性。结合《普通高中化学课程标准(2017年版)》和有机物的组成模型,分析了碳骨架和官能团对有机物性质的影响和2019年版人教版高中化学教材中相关内容的变化,并通过实例介绍了与烷烃性质相关的有机物通性的应用。     

饱和烷烃分子C_nH_(2n+2)(n=4-6)的电子动量光谱(英文)

使用B3LYP/TZVP//B3LYP/aug-cc-pVTZ方法系统研究了饱和烷烃分子CnH2n+2(n=4-6)的轨道电子动量光谱,比较了同分异构体CnH2n+2(n=4-6)对轨道动量分布的影响.结合二维空间分析方法对电子在坐标空间中的密度分布进行了系统的研究.计算结果表明,最内价壳层电荷分布主要由s电子贡献,第二近邻芯价壳层则主要由p电子贡献,而其余的价壳层则为sp杂化.最内价轨道表现出最大的谱线强度并且远大于其它轨道的谱线强度,而且正烷烃的谱线强度要大于异烷烃等同分异构体的谱线强度,表现出了明显的与甲基移动的个数有关的性质.     

2-Cyclopropyliden-1,3-cycloalkandione als Zwischenstufen einer nukleophilen Substitution am Dreiring

Reaction of morpholinobicycloalkyl-dimedone4 C with various CH-acids3 leads to a substitution of theexo-dimedone unit as a consequence of a strong preference of theexo-leaving group in a bicyclic compound of type4 and5, respectively. Dimedone (3 C) as a nucleophile, however, makes theexo substitution unproductive in4 C and allows the displacement of the morpholino moiety leading to12 C. Thus compounds12 C–12 F could be obtained directly from the N,O-acetal1 and the CH-acids3 C–3 F by a twofold substitution, the isolation of the monoalkylated compounds4 not being necessary. Formation of12 C–12 F involves aMichael addition of3 C–3 F to the unstable 2-Cyclopropylidene-1,3-cycloalkanedione intermediates7 C–7 F. Cyclopentanedione3 F as a CH-acid and1 gave the enamine17 F besides12 F. The Hexahydroazepino-N,O-acetal19 in this special case was superior leading exclusively to12 F.

     

Additive Schemes for Calculating the Properties of Alkane Conformers Including Interdependent Bond Rotation. I. Enthalpy

A technique is suggested for evaluating the properties of alkane conformers using the parameters of internal rotation of interdependent C-C bonds. To determine the mean conformational composition of a rotational equilibrium mixture of alkane conformers, one need not exhaust the latter because the contribution of the conformation energy to alkane enthalpy can be expressed in terms of the product of tensors with further convolution over indices.     

位阻型金属卟啉的合成及其催化烷烃基化的反应

本文用平衡法制备了中位-四(3,5-二叔丁基-4-甲氧基等基)卟啉(T~D~T~B~M~OPP), 并制备了该卟啉的铁、锰、钴、锌、铜、镍的金属配合物。经红外光谱、电子光谱、核磁共振谱, 元素分析等确认了这些均未见报道的金属卟啉。考察了在温和条件下, 以T~D~T~B~M~O PP Fe^III C和T~D~T~B~M~O PP Mn^III Cl为了催化剂, PhIo为氧化剂, 在CH~2Cl~2中氧化n-C~6H~1~4的反应, 并将结果与别的催化剂进行了比较。