Liquid–liquid phase diagrams of H2O + 2-butanol + potassium phosphate and H2O + 2-butanol + Na2CO3 systems at 298.15 K

The phase diagrams for the ternary systems H₂O?+?2-butanol?+?K₂HPO₄/KH₂PO₄ (pH?=?7) and H₂O?+?2-butanol?+?Na₂CO₃ at 298.15?K were determined. Experimental binodals and tie lines for these systems are presented. The experimental results were correlated using an improved regular solution theory. The agreement between the correlation and experimental data is good.     

Experimental Study of Vapor–Liquid Equilibrium Data for Acetone + Methanol + 1-Methyl-3-octylimidazolium Thiocyanate

An experimental study on the isobaric vapor–liquid equilibria for the ternary system of acetone?+?methanol?+?1-methyl-3-octylimidazolium thiocyanate ([Omim][SCN]) as well as the two acetone?+?ionic liquid (IL) and methanol?+?IL binary systems was performed at 100 kPa using a recirculating still (VLE 602 Fischer apparatus). A low IL mole fraction of 0.027 was found to be sufficient break the azeotrope due to the high and specific interactions with acetone and methanol. The nonrandom two-liquid model was used to represent the experimental data. The results are compared with those in the literature for the same mixed solvent system using other ILs.     

Influence of Temperature on Liquid–Liquid Equilibrium of Methanol + Toluene + Hexane Ternary Systems at Atmospheric Pressure

Phase equilibria of methanol?+?toluene?+?hexane ternary systems at (278.15, 283.15, 288.15 and 293.15) K at atmospheric pressure were investigated. The influence of temperature on the liquid–liquid equilibrium is discussed. All chemicals were quantified using gas chromatograph with a thermal conductivity detector coupled to a ChemStation and nitrogen as gas carrier, their mass fractions were higher than 0.999. From literature are found two articles from the same system at different temperatures studied here. Experimental data are compared with literature values. Values calculated using the NRTL and UNIQUAC equations are compared with the experimental data and it is found that the UNIQUAC equation fitted the experimental data better than the NRTL model for this ternary system.     

Physical properties of the ternary mixture ethanol + water + 1-hexyl-3-methylimidazolium chloride at 298.15 K

In this work, densities and refractive indices of the ternary mixture ethanol?+?water?+?1-hexyl-3-methylimidazolium chloride ([C₆mim][Cl]) and of the binary systems containing the ionic liquids (ILs) have been measured at 298.15?K and atmospheric pressure. Excess molar volumes and changes of refractive indices on mixing were determined from experimental data. The binary data were correlated with the Redlich–Kister equation, while the Cibulka equation was applied for the ternary system.     

Liquid–Liquid Equilibrium of Water + 1-Propanol or 1-Butanol + Dibutyl Ether Ternary Systems: Measurements and Correlation at Three Temperatures

Liquid–liquid equilibrium (LLE) date for the ternary systems of {water?+?1-propanol?+?dibutyl ether (DBE)} and (water?+?1-butanol?+?DBE) were determined at T?=?(293.15, 303.15, 308.15) K under atmospheric pressure. Distribution coefficients and separation factors of 1-propanol in the mixtures were calculated and are discussed. The influence of temperature on the liquid phase regions was analyzed. In addition, the experimental values were correlated well with the modified and extended UNIQUAC models; the modified UNIQUAC model represents the data better than the extended UNIQUAC model.     

Liquid–Liquid Equilibrium of the Quaternary Systems <Emphasis Type="Italic">n</Emphasis>-Octane or Decane + Toluene + Dimethyl Sulfoxide + Methanol or Ethanol at 298.15 K: Experimental Data and Correlation

In this work, the effect of addition of methanol or ethanol to dimethyl sulfoxide to extract toluene from alkanes was studied. Liquid–liquid equilibria data of the four quaternary systems: {methanol (1)?+?DMSO (2)?+?octane (3)?+?toluene (4)}, {ethanol (1)?+?DMSO (2)?+?octane (3)?+?toluene (4)}, {methanol (1)?+?DMSO (2)?+?decane (3)?+?toluene (4)} and {ethanol (1)?+?DMSO (2)?+?decane (3)?+?toluene (4)} were obtained at 298.15 K and 101.3 kPa. The thermodynamic consistency of the experimental data was verified using the Othmer–Tobias and Hand tests. Selectivities and distribution ratios of the four quaternary systems were calculated from experimental data to evaluate the capacity of these two mixed solvents to extract toluene from octane and decane. A comparison of the results obtained was carried out. The NRTL model was used to correlate experimental data and the correlated results are in good agreement with experimental data.     

Isobaric Vapor–Liquid Equilibrium Data for the Quaternary System of sec-Butyl Acetate + sec-Butyl Alcohol + Dimethyl Sulfoxide + 1-Ethyl-3-methylimidazolium Acetate at 101.3 kPa

Journal of Solution Chemistry - The isobaric vapor–liquid equilibrium (VLE) data for the quaternary system sec-butyl acetate (SBAC)?+?sec-butyl alcohol...     

晶态C60,K3C60,K6C60的能带计算

本文用紧束缚法的ＥＨＭＯ三维晶体轨道程序进行计算求得了Ｃ６０，Ｋ３Ｃ６０和Ｋ６Ｃ６０的能带结构，并得到了一系列过去未曾见过报导的原子投影态密度、轨道、原子重叠布据、原子电荷、轨道矢量等数据。从这些能带图中可以充分说明三种物质的区别，并可解释Ｋ３Ｃ６０的超导性和Ｃ６０与Ｋ６Ｃ６０的绝缘性。     

Quaternary Liquid–Liquid Equilibria for Aqueous Systems Containing Dimethyl Carbonate at 298.15 K

Experimental tie-line data for two ternary systems, water + dimethyl carbonate + methanol or ethanol, and two quaternary systems, water + dimethyl carbonate + toluene + methanol or ethanol were investigated at 298.15 K and atmospheric pressure. The experimental liquid–liquid equilibrium data were correlated using a modified UNIQUAC activity coefficient model with binary and ternary as well as quaternary parameters. The calculated results were further compared with those obtained from an extended UNIQUAC model.     

Viscometric and volumetric properties of benzene + methyl acetate,or + methyl propanoate,or + methyl butanoate binary systems at 283.15, 298.15 and 313.15 K

Viscosities and densities of three binary liquid mixtures, benzene?+?methyl acetate, benzene?+?methyl propanoate and benzene?+?methyl butanoate, have been measured at 283.15, 298.15 and 313.15?K, and atmospheric pressure. From experimental data, viscosity deviation, excess energy of activation for viscous flow, and excess molar volume were calculated and satisfactorily correlated with Redlich and Kister equation. Empirical and semiempirical equations and the predicted group-contribution method, universal automatic computer, were applied.     

Liquid—Liquid Equilibria for the Water-ethanol-methyl Ethyl Ketone Ternary System at 298.15 and 318.15 K

Abstract

Ternary liquid—liquid equilibrium data for the system water-ethanol-methyl ethyl ketone were obtained at 298.15 and 318.15 K. Data for the binodal curves have been determined by the cloud-point method and conjugate points on tie-lines were determined by gas-chromatographic analysis. Tie-line data at each temperature were satisfactorily correlated by the Othmer and Tobias' method and the plait points coordinates were estimated. The experimental data were also fitted with the UNIFAC group contribution method for the activity coefficients using the isoactivity conditions as restraint equations and with the NRTL and UNIQUAC models.     

Studies on solution properties of ternary mixture of acetophenone + n-amyl alcohol + dichloromethane and its corresponding binaries at 298.15 K

The excess values of molar volume (V ^E), viscosity deviation (Δη), deviation in isentropic compressibility (ΔK_S ), excess molar refraction (ΔR) and excess Gibbs energy of activation (ΔG^*E ) of viscous flow have been investigated from the experimentally measured densities, viscosities, sound speeds and refractive indices for three binary mixtures of acetophenone?+?n-amyl alcohol, acetophenone?+?dichloromethane and n-amyl alcohol?+?dichloromethane and their corresponding ternary mixtures at 298.15?K over the entire composition range. The calculated quantities are further fitted to the Redlich–Kister equation to estimate the binary fitting parameters and standard deviations from the regression lines. The excess or deviation properties were found to be either negative or positive depending on the molecular interactions and the nature of liquid mixtures and have been discussed in terms of molecular interactions and structural changes.     

Solubility of anthracene in binary alkane + ethanol solvent mixtures at 298.15 K

Experimental solubilities are reported for anthracene in six binary alkane?+?ethanol solvent mixtures at 298.15?K. The alkane solvents studied were hexane, heptane, octane, cyclohexane, methylcyclohexane and 2,2,4-trimethylpentane. Results of these measurements were used to test a mathematical representation based on the combined nearly ideal binary solvent (NIBS)/Redlich–Kister equation. For the six systems studied, the combined NIBS/Redlich–Kister equation was found to accurately describe the experimental data, with an average absolute deviation between measured and back-calculated values being approximately ±0.5%.     

Solubility of anthracene in binary toluene + alcohol solvent mixtures at 298.15 K

Experimental solubilities are reported for anthracene in eight binary toluene?+?alcohol solvent mixtures at 298.15?K. The alcohol solvents studied were 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, 2-butanol, 2-methyl-1-propanol and 3-methyl-1-butanol. Results of these measurements were used to test a mathematical representation based on the combined nearly ideal binary solvent (NIBS)/Redlich–Kister equation. For the eight systems studied, the combined NIBS/Redlich–Kister equation was found to accurately describe the experimental data, with an average absolute deviation between the measured and back-calculated values being approximately ±0.4%.     

Liquid–liquid equilibria of alkane (C10/C12/C14)+1,4-diisopropylbenzene+sulfolane at 323.15, 348.15 and 373.15 K

Tie line data have been determined at 323.15, 348.15 and 373.15 K for the ternary liquid–liquid equilibria (LLE) of alkane (C10/C12/C14)+1,4-diisopropylbenzene+sulfolane systems. The addition of 1,4-diisopropylbenzene to sulfolane is found to increase the solubility of alkanes in the order of n-decane>n-dodecane>n-tetradecane and the relative mutual solubility of 1,4-diisopropylbenzene is higher in n-decane+sulfolane than in n-dodecane+sulfolane or n-tetradecane+sulfolane mixtures. The tie line data were correlated with the well-known UNIQUAC and NRTL models. The calculated equilibrium mole fractions based on the UNIQUAC model are better than those based on the NRTL model. The values of selectivity and distribution coefficient were derived from the equilibrium data.     

WDX Analysis of Rapidly Quenched Nd-Fe-B Alloys with Ti + C Additives

 Quenched stoichiometric Nd-Fe-B alloys with Ti + C additives, which improve the hard magnetic properties, were investigated by EPMA technique. The exact quantitative wavelength dispersive analysis meets with two problems: the carbon blank value and the C-Kα line coincidence with Nd-Mγ, Nd-Mα and Nd-Mζ of higher diffraction orders. The carbon blank value depends on the special residual gas pressure in the recipient and was determined by repeated measurements of a carbon free iron reference specimen e.g. with subsequent corrections of the carbon content. The second problem can be solved by blanking out the Nd induced contribution to the C-Kα region by a differential detection mode. In this case an energy discriminator was used to set a lower and an upper level in order to suppress the neighbouring coincident lines. The optimized analysis allowed an exact determination of carbon content in all investigated phases.     

Liquid–Liquid Equilibria of Some Aliphatic Alcohols + Disodium Hydrogen Citrate + Water Ternary Systems at 298.15 K

In this paper, the liquid?Cliquid equilibria for 1-propanol, 2-propanol or 2-methyl-2-propanol + disodium hydrogen citrate aqueous two-phase systems at 298.15 K were studied. The experimental binodal curves at 298.15?K are reported, and the parameters of the Merchuk equation, modified as a nonlinear function of mixed solvent properties and used for the simultaneous correlation of the experimental binodal data. Moreover, the salting-out ability of different salts and different alcohols with different anions is discussed. Additionally, experimental tie-line data are reported at 298.15 K. The generalized electrolyte-NRTL model of the mixed solvent electrolyte systems (e-NRTL) satisfactorily used for the correlation of the tie-line compositions; restricted binary interaction parameters were also obtained.     

碳60材料和新型超导体K3C60最近研制成功

据悉,今年6月10日,北京大学化学系和物理系研究小组研制成功了碳60材料,经红外、核磁、质谱等方法测定,该材料的各项数据均接近国际水平。碳60,又称足球烯,是石墨、金刚石之后新发现的碳的第三种同素异形体。由于它具有含60个碳原子的稳定的球形结构,有可能成为新型的润滑剂或催化剂基体。若掺少量碱金属,碳60材料又具有超导性能。继碳60的合成成功,在7月9日,北京大学研究小组又与中科院物理研究所合作研制成功K_3C_(60),超导起始温度为17.9K。K_3C_(60)是一种碳60的碱金属化合物,一种新型的高温超导体,它的超导转变温度远高于已发现的各种有机超导体。上述两项最新成果说明了我国在高温超导研究方面继续走在世界前列。