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由于碳酸丙烯酯(PC)具有较宽的液相区间(mp:224.0K,bp:514.9K)、较高的介电常数(64.92,298.15K)和较大的偶极矩(4.94D),它是一个在工业和科学研究中有广泛应用的非质子型极性溶剂。已有大量文献就PC溶液中电解质-PC、非电解质-PC和离子-离子间的相互作用情况作了报导。对于非电解质-电解质-PC三元系中溶质-溶剂间的相互作用情况还缺乏了解。本文希望通过测定非电解质溶质在PC的电解质溶液中的无限稀释活度系数γ_1~∞,对非水溶液中的溶质-溶剂作用情况有新的了解。气液色谱法(CLC)是测定无限稀释溶液活度系数的有效方法之一。作者曾利用GLC测定了一些烃、氯代烃、醇、酮在环丁砜电解质溶液中的无限稀释活度系数和盐效应常数. 相似文献
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The gas-liquid chromatographic method was used to measure the activity coefficients at infinite dilution (γ_1~∞) of some nonelectrolyte solutes in salt containing solutions of propylene carbonate at 333.2 K. For examining the relationship between lgγ_1~∞ and salt concentrations, the salt effect coefficients of solutes were calculated, and the interactions of solute with salt were disscused. Furthermore, the equilibrium constant of complex interaction between chloroform with anions has been obtained. 相似文献
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本文将气液色谱法用于测定环丁砜含盐溶液中以烃、芳烃、氯代烃、醇和酮为溶质的盐效应常数,结果表明,大多数溶质的盐效应关系可用Setschenow方程描述;负离子的性质对盐效应的影响比正离子更重要;负离子的电子向氯代烃中氯原子3d空轨道的迁移作用对其k_s的影响很大。 相似文献
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用气液色谱有限浓度法测量了313.15K下C_1—C_4各正构醇在角鲨烷中的活度系数。用连续缔合的Wiehe-Bagley型和Kretschmer-Wiebe型结合物理作用项的双参数模型对实验数据进行处理,得到各醇的自缔合常数和物理相互作用参数。 相似文献
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本文采用Otsuki-Williams式汽液平衡釜测定了甲酸-乙酸-水体系及甲酸-乙酸-水-氯化钙体系在98658.28Pa下汽液平衡数据。氯化钙的加入量为0.5mol/(kg溶剂)。结合盐效应的作用情况,对相图进行了分析。研究结果表明:氯化钙的加入对体系起了物理化学作用,它与盐溶、盐析现象有关。 相似文献
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在278.15~318.15K间隔10K)下,测定了无液接电池Pt,H_2(g,P~θ│HCl(m_E)│AgCl-AgPt,H_2(g,P~(?))│HCl(m_E),GL(m_N)│AgCl-Ag的电动势,其中GL为丙三醇,m_E=0.005~0.1mol·kg~(-1),m_N=0.4~1.0mol·kg~(-1).实验数据用来计算HCl-GL-H_2O体系的盐效应常数k_s及HCl-GL在水中的相互作用的热力学参数f_(EN)(g_(EN),S_(EN),h_(EN)和c_(p.EN)).结果表明k_s>0,g_(EN)>0,S_(EN)>0,C_(p.EN)<0.在353K时k_s有最小值0.0076kg·mol~(-1).f_(HCl~GL)的数值比f_(HCl~PG)(PG是1,2-丙二醇)小.应用结构相互作用模型和基团加合性原理分析讨论了这些参数的符号及其随温度变化的规律. 相似文献
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在278.15~318.15K(间隔10K)下, 测定了无液接电池Pt,H~2(g,p)│HCl(m~E)│AgCl-AgPt,H~2(g,p)│HCl(m~E),GL(m~N)│AgCl-Ag的电动势, 其中GL为丙三醇, m~E=0.005~0.1mol·kg^-^1,m~N=0.4~1.0mol·kg^-^1。实验数据用来计算HCl-GL-H~2O体系的盐效应常数k~s及HCl-GL在水中的相互作用的热力学参数f~E~N(g~E~N,s~E~N,h~E~N和C~p~,~E~N)。结果k~s>0,g~E~N>0, s~E~N>0, C~p~,~E~N<0。在353K时k~s有最小值0.0076kg·mol^-^1。f~H~C~l~-~G~L的数值比f~H~C~l~-~P~G(PG是1,2-丙二醇)小。应用结构相互作用模型和基团加合性原理分析讨论了这些参数的符号及其随温度变化的规律。 相似文献
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本文测定了278.2~318.2K间的五个温度下七种浓度的NaOAc分别在10, 20,30, 40, 50, 60, 70, 80, 90及100%MeOH-H~2O体系中的摩尔电导Λ, 并应用FOS,Pitts, L-W, F-78等四个电导方程对实验数据进行了拟合处理, 得到了三个拟合参数Λ~O, K~Λ及R(或α)。最后, 对四个方程与实验的吻合程度, 温度、溶剂组成等对Λ~O、K~Λ的影响规律及溶质-溶剂相互作用进行了讨论。 相似文献
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Dmitri V. Sevenard Olesya Kazakova Enno Lork Thomas Dülcks Dmitri L. Chizhov Gerd-Volker Rschenthaler 《Journal of Molecular Structure》2007,846(1-3):87-96
4-Phenyl-2,6-bis(trifluoroacetyl)cyclohexanone and its dilithium salt were synthesized starting from the commercially available 4-phenylcyclohexanone. With X-ray structure analysis of these compounds, for the first time the solid state structure determination for a fluorinated 1,3,5-triketone and an alkaline salt of 1,3,5-triketone was achieved. The subsequent multinuclear NMR and MS investigations revealed that in solution and gas phase, analogously to the crystal, both compounds exist predominantly in a highly delocalized double U-enol(ate) form. The carbonyl O…O distances in the dilithium salt were established to be considerably longer than the distances between oxygens of the parent 1,3,5-triketone, bonded by strong (short) resonance assisted hydrogen bonds. Among the 1,3,5-tricarbonyl compounds with known crystal structure, the entitled 1,3,5-triketone shows comparatively weak delocalization over the conjugated bis-enolone backbone. 相似文献
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Sandro Campestrini Alessandro Cagnina 《Journal of molecular catalysis. A, Chemical》1999,150(1-2):77-86
The oxidation of variously ring-substituted 1-phenylethanols with Ph4PHSO5 catalysed by Mn(TMP)Cl and Mn(TDCPP)Cl in the presence of 4-tert-butylpyridine was studied in 1,2-dichloroethane homogeneous solution. The process leads only to C–H bond cleavage products, namely acetophenones. The oxidation rates are independent of the substrate concentration and, when Mn(TMP)Cl is the catalyst, even of the substrate nature. By increasing the concentration of 4-tert-butylpyridine, which acts as an axial ligand of the catalyst, a bell-shaped curve for the rate constants trend is observed. Hammett plots obtained by changing the substituents on the phenyl ring of the benzylic alcohol give different ρ values depending on the technique employed for rate constants determination, i.e., individual or competitive experiment. The observations reported above, together with a KIE of 2.5 in 1-
-1-phenylethanol oxidation measured by competitive experiment, are rationalised on the basis of a mechanistic scheme in which the oxo-manganese derivative is formed in the rate determining step of the catalytic process. Furthermore, it is suggested that alcohol dehydrogenation proceeds through a hydride abstraction involving an alcohol-oxo-porphyrinato complex. 相似文献
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在ZINDO方法的基础上, 按完全态求和公式编制了计算分子的二阶非线性光学系数张量元βijk的程序, 并以此为基础计算了BNPT-DTO, BNPT-DTT分子二次谐波条件下的二阶非线性光学系数, 从分子水平研究了其分子的光学倍频性质及分子倍频与晶体宏观倍频的关系, 计算结果较好地说明了实验现象。 相似文献
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The effect of very low concentrations of ethanol, 2-propanol and phenol on the swelling degree of poly(ethylene-co-vinyl alcohol) (EVAL) in water was investigated. The effect of phenol on the swelling degree of EVAL was remarkably large compared to that of ethanol and that of 2-propanol. Theoretical analysis on the basis of Flory-Huggins theory using three binary interaction parameters could appropriately predict the EVAL swelling degree in ethanol/water and 2-propanol/water mixtures. However, the theoretical swelling degree of EVAL in phenol/water mixtures needed a ternary interaction parameter (χT) to match with experimental data points. An optimum value of χT for the water-phenol-EVAL system was found to be −3.3. The relationship between the ternary interaction parameter and the structure of water from observations of the effect of phenol on the EVAL swelling was discussed. Based on the analysis of low-frequency Raman spectroscopy reported by Suzuki et al. [J. Chem. Phys. 107 (1997) 5890], the contribution of χT to the EVAL swelling was attributed to the increase of the entropy in bulk water due to the effect of phenol on the disruption of the tetrahedral hydrogen-bonded networks of water molecules. This, in turn, induced an increase of water absorption in EVAL. 相似文献
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[6Li]-α-(phenylthio)benzyllithium 1-6Li was studied in THF/[D8]THF solution (1:1) in the presence of several acyclic and cyclic polyether ligands by 1H,6Li-HOESY, 1H and 13C NMR spectroscopy. The question whether these ligands are bonded to lithium or not is important for physical–organic investigations as well as for studies of the ground state of (stereoselective) reactions of organolithium compounds in the presence of such ligands. Dimethoxyethane is not bonded to lithium under these conditions. The acyclic ethers diglyme and triglyme coordinate only weakly to the organolithium compound and form contact ion pairs (CIPs) at 25°C. At −80°C, CIPs are in equilibrium with separated ion pairs (SIPs). Very stable complexes of 1-6Li are obtained with crown ether ligands. Addition of 12-crown-4 and 15-crown-5, respectively, results in the exclusive formation of SIPs at 25°C and −80°C. With 18-crown-6, a CIP–SIP equilibrium is observed at 25°C which is shifted entirely to the SIP side at −80°C. Graphical analyses of the 1H and 13C NMR spectra of the polyether complexes of 1-6Li revealed correlations between the chemical shifts of the para phenyl carbon C-5, the para phenyl proton H-5, the benzylic carbon C-1, and the proton–carbon coupling constant J(C-1,H-1) of 1-Li, which are useful probes for the charge distribution within the carbanionic moiety of 1-6Li in the respective complexes, and thus for the ion pair character as a function of the polyether complexation of lithium. 相似文献
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Simon J. Cranson Mark A. Fox Robert Greatrex Norman N. Greenwood 《Journal of organometallic chemistry》1998,550(1-2)
11B NMR spectra of tetraborane(8) carbonyl, B4H8·CO 1, reveal a changeover in the distribution of isomers in going from toluene solution to the gas phase. Fortuitously the distribution is 60:40 in each case, but comparison with published electron diffraction data and ab initio/IGLO computations indicates that the CO group is disposed endo with respect to the B4 `butterfly' framework in the predominant isomer in the gas phase, and exo in solution. The results also allow conclusions to be drawn about the geometries of other B4H8·L isomers on the basis of their reported proton NMR chemical shifts. Reactions of B4H8·CO with ethene and propene at ca. 30 bar yield products, R4B4H4·CO (R=Et 2 or Pr3 3), in which all four wingtip hydrogen atoms of the tetraborane carbonyl have been replaced by alkyl groups. Variable-temperature 11B and 1H NMR spectra of 2 and 3 reveal interesting fluxional behaviour. 相似文献