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961.
962.
The phase of a fluid (liquid, vapor) at a given state is normally identified by comparing the properties of the fluid at the given state with saturation properties. In this paper we present a thermodynamic method for determining the phase of a fluid from the partial derivatives of pressure, volume and temperature without reference to saturated properties. The method has immediate application in a variety of phase equilibria calculations, particularly for liquid-liquid or vapor-liquid-liquid equilibria calculations in process simulators. 相似文献
963.
Yan-Yang WuKui Chen De-Tao PanJia-Wen Zhu Bin WuYa-Ling Shen 《Fluid Phase Equilibria》2011,305(2):101-105
(Liquid-liquid) equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 3-hydroxy-2-butanone + ethyl ethanoate) at 298.15 K, 308.15 K and 318.15 K and 101.3 kPa. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using Othmer-Tobias correlation. The LLE data of the ternary systems have been predicted by UNIFAC method. 相似文献
964.
Kamil PaduszyńskiJim Chiyen Deresh RamjugernathTrevor M. Letcher Urszula Domańska 《Fluid Phase Equilibria》2011,305(1):43-52
The phase diagrams for binary systems of {1-propyl-1-methylpiperidinium bis{(trifluoromethyl)sulfonyl}imide [PMPIP][NTf2] + an alcohol (butan-1-ol, pentan-1-ol hexan-1-ol, heptan-1-ol, octan-1-ol, decan-1-ol and undecan-1-ol} have been determined at atmospheric pressure using a dynamic method. The influence of an alcohol chain length is discussed for this ionic liquid (IL). A systematic decrease in the solubility is observed with an increase of the alkyl chain length of an alcohol. Liquid + liquid phase equilibrium (LLE) with an upper critical solution temperature was observed. The phase diagrams reported are compared to systems published earlier with the 1-alkyl-1-methylpiperidinium-based ionic liquid. The basic thermal properties of the pure IL, i.e. melting temperature and the enthalpy of fusion, the glass transition temperature and heat capacity at melting temperature have been measured using a differential scanning microcalorimetry technique. The density of [PMPIP][NTf2] as a function of temperature was measured. The results of the LLE correlation with two models viz. the lattice theory based on non-random hydrogen bonding (NRHB) and the Perturbed-Chain Polar Statistical Associating Fluid Theory (PCP-SAFT) are presented. Both models are capable of describing pure fluid properties of IL (densities and solubility parameters) by using one set of parameters and the LLE in binary systems. This is to our knowledge the first paper presenting the SAFT modelling of binary LLE in ionic liquid systems. 相似文献
965.
衍生液提取-高效液相色谱法测定食品中甲醛 总被引:4,自引:0,他引:4
提出了高效液相色谱法测定了几种食品中甲醛含量。以衍生液2,4-二硝基苯肼乙腈溶液-pH 5的磷酸盐缓冲溶液(1+1)的混合溶液为提取剂对样品进行提取,以Agilent C18色谱柱(4.6 mm×250 mm,5μm)为固定相,以甲醇-水(70+30)溶液为流动相分离。甲醛的测定下限(10S/N)为5.0 mg.kg-1。以鲜香菇、鲜鱿鱼、奶粉和面粉样品为基体,分别添加5.0,10.0,20.0 mg.kg-1甲醛标准溶液,回收率在73.3%~97.7%之间,相对标准偏差(n=6)在1.4%~5.0%之间。 相似文献
966.
Two new compounds in the Ca—Cu—Cd system of nominal composition Ca5Cu2Cd and Ca2Cu2Cd9 are synthesized from nearly stoichiometric mixtures of the elements (1100 °C, 48 h). 相似文献
967.
新型功能化离子液体的合成及液-液萃取钕(Ⅲ)的研究 总被引:2,自引:0,他引:2
研究了新型功能化离子液体1-戊基-3-(3-乙基苯基膦酰基)丙基咪唑双(三氟甲基磺酰基)亚胺盐的合成及对Nd(Ⅲ)的萃取性能,考察了水相酸度、萃取时间、杂质离子等对萃取性能的影响。结果表明,在0.13g该离子液体中,萃取时间为30min,5 mL pH 9.0的Nd(Ⅲ)溶液浓度在0.1~5.0μg/mL时,其线性回归方程为Y=-29352+2.423×106ρ(μg/mL),线性相关系数和最低检测限分别为0.9982和0.0025μg/mL。同时研究了离子液体的回收利用,在5%HNO3介质中洗脱30 min,Nd(Ⅲ)洗脱率达86%以上,回收后的离子液体可再利用。 相似文献
968.
《Journal of Coordination Chemistry》2012,65(7):1240-1253
The complex-formation equilibria of dimethyltin(IV) (DMT) with 4-hydroxymethyl imidazole (HMI) and 2,6-dihydroxymethyl pyridine (PDC) have been investigated. Stoichiometry and stability constants for the complexes formed were determined at different temperatures and 0.1?mol?L?1 NaNO3 ionic strength. The concentration distribution of the complexes in solution was evaluated as a function of pH. The effect of dioxane as a solvent on both protonation constants and formation constants of DMT complexes with HMI and PDC are discussed. The thermodynamic parameters ΔH° and ΔS° calculated from the temperature dependence of the equilibrium constants were investigated. 相似文献
969.
Ikuo Ueta Ayako Mizuguchi Koji Fujimura Susumu Kawakubo Yoshihiro Saito 《Analytica chimica acta》2012
A novel needle-type sample preparation device was developed for the effective preconcentration of volatile organic compounds (VOCs) in indoor air before gas chromatography–mass spectrometry (GC–MS) analysis. To develop a device for extracting a wide range of VOCs typically found in indoor air, several types of particulate sorbents were tested as the extraction medium in the needle-type extraction device. To determine the content of these VOCs, air samples were collected for 30 min with the packed sorbent(s) in the extraction needle, and the extracted VOCs were thermally desorbed in a GC injection port by the direct insertion of the needle. A double-bed sorbent consisting of a needle packed with divinylbenzene and activated carbon particles exhibited excellent extraction and desorption performance and adequate extraction capacity for all the investigated VOCs. The results also clearly demonstrated that the proposed sample preparation method is a more rapid, simpler extraction/desorption technique than traditional sample preparation methods. 相似文献
970.
《Analytical letters》2012,45(6):443-454
Abstract Scandium was extracted at pH 5.0 from 0.01 M malonic acid on silica gel column impregnated with Amberlite LA-1. Nickel, zinc, cadmium, mercury, lead, tin, aluminium, and lanthanum in binary mixtures because they could not form malonato complexes. It was separated by the process of selective elution from elements such as zirconium, thorium, uranium, iron(III), gallium, indium, cerium(III), litanium by exploiting difference in stability of malonato complexes. Scandium was separated from multicomponent mixture containing yttrium, titanium, zironium, thorium, uranium and aluminium by a process of selective sorbtion and selective elution. 相似文献