共查询到19条相似文献,搜索用时 78 毫秒
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应用等温流动微量热法测定了298.15 K时互为旋光异构体的D-甘露醇与D-山梨醇在不同浓度的氯化钠水溶液中的稀释焓, 利用 McMillan-Mayer 理论计算了D-甘露醇与D-山梨醇在不同浓度的氯化钠水溶液中的焓对相互作用系数. 结果表明, D-甘露醇和D-山梨醇在氯化钠水溶液中的焓对相互作用系数h2均为正值, h2的值随着氯化钠浓度的增加皆逐渐增大, 但D-山梨醇的焓对相互作用系数h2增大的速率[dh2 /dm(NaCl)]比 D-甘露醇的要大. 根据两多元醇分子构象结构的差异, 溶质-溶质相互作用和溶质-溶剂相互作用对结果进行了解释. 相似文献
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利用量热法测定了298.15K时葡萄糖在一些醇(甲醇、乙醇、1-丙醇、1-丁醇)与甲酰胺的混合溶剂中的溶解热.采用McMilan-Mayer方法,将溶液热力学过量性质与溶液中粒子的相互作用参数相关联,求得了粒子间的焓对相互作用参数和三分子相互作用参数,并就溶质-溶质间的相互作用及溶剂的影响进行了讨论. 相似文献
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由于糖具有特殊的生物和生理性质 ,在工业生产中已有广泛应用 ,故其溶液热力学性质已成为人们感兴趣的研究课题之一 .糖在水溶液中的热力学性质已见文献报道 [1] ,但在非水体系中的有关数据则较少报道 .研究表明 ,溶剂介质的变化对溶质的溶剂化状态和溶质间相互作用的影响较大 ,选用酰胺为溶剂可以获得模拟蛋白质环境条件下的溶质 -溶剂、溶质 -溶质间相互作用的信息 [2~ 4] .本文利用微量量热法测得了葡萄糖在杂环化合物与甲酰胺的混合溶剂中的溶解焓 .如果把杂环化合物作为 x,葡萄糖作为 y,按照 Mc Millan- Mayer[5 ] 理论 ,1 mol葡萄… 相似文献
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酰胺是肽的基本结构单元, 而且在蛋白质的二级结构中与酰胺联系的氢键对蛋白质的稳定起着十分重要的作用. 作为蛋白质模型化合物热力学性质研究的一部分, 报道了甲酰胺在乙二醇水溶液中的稀释焓. 相似文献
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葡萄糖与醇在甲酰0胺溶液中的焓相互作用参数 总被引:4,自引:2,他引:2
利用量热法测定了298.15K时葡萄糖在一些醇(甲醇、乙醇、1-丙醇、1-丁醇)与甲酰胺的混合溶剂中的溶解热。采用McMillan-Mayer方法,将溶液热力学过量性质与溶液中粒子的相互作用参数相关联,求得了粒子间的焓对相互作用参数和三分子相互作用参数,并就溶质-溶质间的相互作用及溶剂的影响进行了讨论。 相似文献
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The enthalpies of mixing of aqueous glucose solutions and six kinds of aqueous amino acid solutions (glycine, L-alanine, L-serine, L-valine, L-proline, and L-threonine) and their respective enthalpies of dilution have been determined at 298.15 K using flow microcalorimetry. The experimental data have been analyzed in terms of the McMillan–Mayer model to obtain the heterotactic interaction coefficients. The results have been interpreted from the point of view of solute–solute interactions. 相似文献
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The enthalpies of mixing aqueous ethanol solutions and with aqueous amino acid solutions (glycine, L-alanine, L-serine, L-threonine, and L-proline) and their respective enthalpies of dilution have been determined at 25°C by a flow microcalorimetric system. The experimental data have been analyzed in terms of McMillan-Mayer formalism to obtain the enthalpic virial coefficients for heterotactic interaction. The results have been interpreted from the point of view of solute-solute interactions. 相似文献
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The enthalpies of mixing have been determined for five kinds of aqueous amino acids solutions (glycine, L-alanine, L-valine, L-serine, and L-proline) with 2-chloroethanol by an LKB-2277 Bio Activity Monitor at 298.15 K. In addition, the enthalpies of dilution at 298.15 K of aqueous solutions containing the five kinds of amino acids and 2-chloroethanol have been obtained. The heterotactic enthalpic pairwise interaction coefficients of the virial expansion of excess enthalpy were evaluated and interpreted from the point of view of solute–solute interactions. In comparison with ethanol, 2-chloroethanol shows a stronger exothermic interaction with amino acids because of its hydrophilic Cl atom and a more acidic –OH group. Using the additivity groups concept by Savage and Wood (SWAG), contributions of each of functional group of the amino acids and ethanol and 2-chloroethanol have been estimated. 相似文献
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ZHU Yan PANG Xian-hong YU Li . Department of Chemistry Chemical Engineering Taishan Medical University Tai’an P. R. China . Key Laboratory of Colloid Interface Chemistry Ministry of Education Sh ong University Jinan 《高等学校化学研究》2011,(1)
The enthalpies of mixing of L-arginine with 2,2,2-trifluoroethanol and their respective enthalpies of dilution in aqueous solutions at 298.15, 303.15 and 310.15 K were determined as a function of the mole fraction by flow microcalorimetric measurement. These experimental results were analyzed to obtain heterotactic enthalpic interaction coefficients(hxy, hxxy, hxyy) according to the McMillan-Mayer theory. The hxy coefficients between L-arginine molecule studied and 2,2,2-trifluoroethanol molecule in aqueous... 相似文献
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《Analytical letters》2012,45(10):647-658
Abstract The electrochemical behavior of the system Eu(III)/Eu(II) in aqueous formamide solutions was studied by current reversal chronopotentiometry at a mercury pool electrode, in 1 M NaClO4 The results indicate that double layer effects must be considered rather that ion solvation effects when explaining the influence of formamide on the Eu(III)/Eu(II) electrode reaction. 相似文献
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Summary. Solubilities of methyl acetate (MeOAc), ethyl acetate (EtOAc), 1-propyl acetate (1-PrOAc), 1-butyl acetate (1-BuOAc), 2-methyl-1-propyl
acetate (iso-BuOAc), 2-butyl acetate (sec-BuOAc), 2-methyl-2-propyl acetate (ter-BuOAc), 1-pentyl acetate (1-PeOAc) and 1-hexyl acetate (1-HeOAc) in water and in aqueous sodium chloride solutions at concentrations ranging up to 1.0 molċdm−3 were determined at 25.0°C by analyzing the saturated aqueous or salt solutions. Solubility ratios of alkyl acetates in pure
water and in aqueous sodium chloride solution were calculated and found to be linearly dependent on the concentration of sodium
chloride. The solubility ratios were also calculated by the approach of the scaled particle theory and according to the theories
of McDevit and Long, Cross, Conway et al., and Aveyard. All these theories, except that of Conway, correctly predict the order of magnitude of the experimental results, but do not discriminate between isomeric butyl acetates.
The theoretical values obtained from the scaled particle and Aveyard theories coincide well with the experimental values, especially for the higher alkyl acetates. The purely electrostatic theory
of Conway et al. not even predicts the salting-out effect for the alkyl acetates investigated.
Received July 12, 1999. Accepted September 23, 1999 相似文献
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The dilution enthalpies of formamide in aqueous methanol and ethanol solutions have been determined using a CSC-4400 isothermal calorimeter at 298.15 K. The homogeneous solution enthalpic interaction coefficients have been calculated over a range of alcohol concentrations according to the excess enthalpy concept. The results show that the enthalpic pair interaction coefficients h
2 of formamide are negative in aqueous alcohol solutions and pass through a minimum in mixed solvents, whereas the h
2 coefficients of formamide in aqueous ethanol solutions are more negative than those in aqueous methanol solutions. The results are discussed in terms of solute-solute and solute-solvent interactions. 相似文献
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Y. Li H. Xingen L. Ruisen X. Guiying 《Journal of Thermal Analysis and Calorimetry》2004,76(2):443-454
Enthalpies of dilution of aqueous L-serine, pyridine and methylpyridine solutions and their enthalpies of mixing have been determined by a mixing-flow microcalorimeter
at 298.15 K. The data have been analyzed in terms of McMillan-Mayer formalism to fit to virial polynomials from which the
heterotactic enthalpic pairwise interaction coefficients, h
xy, betweenL-serine and pyridine and methylpyridine isomers have been evaluated. The results obtained in the present paper are compared
with those reported in the earlier paper about glycine and L-alanine in the same organic solvent aqueous solutions, giving a global insight of the interaction mechanism between the a-amino
acids and pyridine and methylpyridine from the point of view of solute-solute interactions and substituent effects of methyl
groups introduced into the pyridine ring.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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D-甘露醇与D-山梨醇在纯水和卤化钠水溶液中的稀释焓 总被引:1,自引:0,他引:1
应用等温流动微量热技术测定了298.15 K下D-甘露醇和D-山梨醇在纯水和卤化钠水溶液中的稀释焓,利用M cM illan理论计算了D-甘露醇和D-山梨醇在纯水和卤化钠水溶液中焓相互作用系数.结果表明,D-甘露醇和D-山梨醇在纯水和卤化钠水溶液中的二阶焓相互作用系数均为正值,并随着卤离子半径的变化而相应变化;且同种溶剂中,D-甘露醇的二阶焓相互作用系数要大于D-山梨醇的.结合两分子结构的差异,通过溶质-溶质相互作用和溶剂-溶质相互作用对这一结果进行了讨论. 相似文献