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1.
The solubility behaviour of several hydrated and anhydrous sulphates has been studied isothermally (26.2±0.06 °C) by using the high-resolution calorimeter previously described. The notion of behaviour recently defined in terms of topoenergetic principles was adopted for these experiments by establishing standard experimental conditions (SEC), mainly covering the geometry of the measuring cell and the figure of merit of the overall calorimetric system. The previously defined parameters from the heat flow recorded at normal and high speed clearly show the oscillatory behaviour generally predicted by the topoenergetic theory. The measuring system used also allows the demonstration of a difference in behaviour for size fractions of the same solute. The overall solubility behaviour under the same SEC for all values of solute mass can be defined in accordance with the universal topoenergetic procedure applied to a large variety of composite and measuring systems. The resulting data associated with the individual (ontogenic) and the group (phylogenic) behaviour can provide Data Banks for general use.  相似文献   

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The process of dilution of aqueous concentrated solutions of the series XSO4 (X=Cu, Na2, Fe, Ni, Mn, Mg) was studied calorimetrically by considering the peak height and area as eigenvalues and the initial concentration as governing potential. The experiments were carried out under standard conditions imposed by topoenergetic principles. The results obtained with the universal procedure recently established define the individual (ontogeny) and the group (phytogeny) behaviour of all the considered solutions with respect to the overall measuring system. These data agree with many other experimental facts showing the following increasing sequence of their power: Mg< Mn < Ni < Fe< Na < Cu. The initial concentration of hydrogen-bonds can be determined by means of standard experiments with the universal topoenergetic procedure proposed for the creation of Data Banks.
Zusammenfassung Der Proze\ der Verdünnung konzentrierter wÄssriger Lösungen der Serie XSO4 (X=Cu, Na2, Fe, Ni, Mn, Mg) wurde kalorimetrisch untersucht, indem Höhe und FlÄche des Peaks als Eigenwerte und die Ausgangskonzentration als dominierendes Potential angesehen wurden. Die Experimente wurden unter von topochemischen Prinzipien auferlegten Standardbedingungen ausgeführt. Die mit der kürzlich eingeführten universellen Prozedur erhaltenen Ergebnisse kennzeichnen das (ontogene) individuelle und das (phylogene) Gruppenverhalten aller in Betracht genommenen Lösungen in Bezug auf das Gesamtme\system. Diese Daten stimmen mit anderen experimentellen Fakten überein. Die von den Kationen ausgehende Wirkung nimmt in der Reihenfolge Mg< Mn < Ni < Fe < Na < Cu zu. Die Ausgangskonzentration der Wasserstoffbindungen kann mittels Standardexperimenten nach der für die Schaffung einer Datenbank vorgeschlagenen universellen topoenergetischen Prozedur bestimmt werden.

XSO4 (X=u, Na2, Fe, Ni, Mn, Mg), , — . . , , () () . , Mg < Mn < Ni < Fe < Na < u. , .
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The interaction between molecular oxygen and bile salts, previously observed using chemiluminescence techniques, is studied in this paper by electrochemical techniques to further highlight the nature of the interaction. A shift of half-wave potential of the first polarographic wave for the reduction of molecular oxygen was observed in solutions in the presence of bile salts. The shift could be related to different phenomena, such as adsorption of bile salt molecules on the mercury electrode, irreversibility of the oxygen reduction reaction, pH of the solution. Experimental results suggest the exclusion of the above mentioned processes and outline the occurrence of a direct interaction between oxygen and bile salts, where the hydrophobic face of bile salt monomers and/or small aggregates are involved, enhancing so dismutation of superoxide ion produced at the electrode. The presence of bile salts in solutions containing triphenylphosphine oxide, a hydrophobic surfactant, increases also the wave of reduction of molecular oxygen. As a consequence bile salts, beside the well-assessed physiological roles, can behave as oxygen carrier and as antioxidant, preventing the oxidation of biological compounds by superoxide ion.  相似文献   

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The heats of mixing of the DNA-AD, Duplex I-AD and Duplex II-one systems were measured at 298.15 ± 0.005 K by using an LKB batch type twin microcalorimeter with a help of spectral measurements. From the results of DNA-AD system obtained, the interaction between DNA and AD is mainly caused by intercalation manner by referring to the result of spectral measurement. And, we estimated the thermodynamic quantities based on the intercalation process. While, from the results of Duplex I-AD and Duplex II-one systems, we concluded that the interactions of these systems may be corresponded to an electrostatic force as binding process rather than an intercalation process.  相似文献   

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In this work, the interaction of an ionic liquid (IL) 1-octyl-3-methylimidazolium chloride ([Omim]Cl) and L-tryptophan was investigated with fluorescence spectroscopic method. The quenching mechanism and binding characteristics of [Omim]Cl with L-tryptophan at different temperatures were studied from fluorescence measurement. The thermodynamic parameters such as free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS), were calculated by thermodynamic equations. The experimental results indicated that [Omim]Cl and L-tryptophan had weak interaction and the mechanism of quenching belonged to static quenching. Hydrogen bonds and van der Waals interactions played important roles in the binding of [Omim]Cl with L-tryptophan.  相似文献   

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Journal of Thermal Analysis and Calorimetry - Exploring the mechanism of the interaction between milrinone drug and lysozyme is important for us to understand the transportation in vivo, metabolism...  相似文献   

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苏现想  刘成虎  吴振 《化学研究》2012,(2):26-30,34
采用量子化学计算中的密度泛函理论(DFT),在B3LYP/6-31+G(d,p)计算水平上研究了离子液体1-乙基-3-甲基咪唑四氟硼酸盐([Emim]BF4)及其与水分子形成的复合物的稳定构型和相互作用能;经振动频率分析得到了[Emim]BF4及其与水的复合物的红外光谱.计算结果表明,相对于水分子与阳离子的作用而言,水分子与阴离子的作用对离子液体结构的影响更大.与此同时,实验测得的[Emim]BF4的红外光谱与计算结果吻合.  相似文献   

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The structure of sodium deoxycholate (NaDC) micellar aggregates has been previously reported to be helical, and two helical models have been proposed for the micellar aggregates of sodium taurodeoxycholate (NaTDC). Here we report NMR and UV-VIS studies on the interaction between acridine orange (AO) and NaDC or NaTDC aqueous micellar solutions. AO is known to aggregate in aqueous solutions. The addition of NaDC or NaTDC causes the breaking of the AO aggregates, although the binding geometry of the two bile salts with AO seems to be slightly different. The cationic dye interacts mainly with the C18 and C,9 methyl groups of the bile salt molecules. This result agrees with one of the two NaTDC helical models and with some of its possible aggregates, and confirms again the helical structure attributed to the NaDC micellar aggregates within the limits of the experimental conditions tested by us.Devoted to Professor Giovannai Battista Marini Bettolo Marconi on the occasion of his 75th birthday.  相似文献   

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利用水热法对蒙东褐煤进行了改性。通过微量热仪测定和分析了煤炭表面骨架大分子和各种官能团与水结合能的大小。结果表明,水热法改性后,褐煤中的羧基和羰基随温度升高显著降低,而羟基的变化比较复杂。计算得到了低阶煤中含氧官能团和煤炭表面骨架大分子亲水能力由大到小的顺序是羧基酚羟基羰基煤炭表面骨架大分子。  相似文献   

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《Fluid Phase Equilibria》2006,244(1):68-77
Heat capacities for nine ionic liquids (IL) have been determined with the “three-step” method using two different differential scanning calorimeters (DSC). In addition, the heat capacities of these ionic liquids have been studied by the modulated-temperature differential scanning calorimetry (MDSC™). The measurements cover a temperature range from 315 to 425 K.  相似文献   

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The interactions between an organic polymer with plasticizing activity and a model surface (CaCO3), with a surface activity similar to the cement one, have been analysed by volumetric analysis and thermal analysis: TG/DTG and DSC. The synthesized polymer has a negative link site (carboxylate) that is able to interact with the substrate and a long ethylene oxide chain that contribute to the dispersing activity. The pattern of the adsorption isotherm suggests the occurring of a step like adsorption, initially characterised by a coil conformation of PEO chain followed by a more PEO strained, linear, conformation as the amount of polymer increases. The polymer adsorption appears to modify the crystalline phase and morphology of the CaCO3 surface as the thermal analysis puts in evidence through the CaCO3 decomposition temperature shifts. SEM analysis confirms the morphology changes induced by polymer adsorption.  相似文献   

14.
The binding properties of amino phosphate ester derivatives, compound 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV spectra, fluorescence spectra, molecular modeling and isothermal titration calorimetry (ITC). The intrinsic binding constants Kb of compound 1 and 2 with CT-DNA were determined by fluorescence spectroscopy and ITC, respectively. The results indicated that the two compounds bind to CT-DNA with different binding affinity, which is in the order of compound 1 > compound 2. At the same time, fluorescence spectra suggested that the mechanism of the binding of the two compounds to CT-DNA is a static enhancing type. According to the ethidium bromide displacement experiments, UV spectra, molecular modeling and ITC studies, it can be concluded that compound 1 and 2 are intercalators that can slide into the G–C rich region of CT-DNA. Furthermore, ITC data showed that compound/DNA binding is enthalpy controlled.  相似文献   

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芳香反离子与离子表面活性剂胶团的相互作用   总被引:5,自引:0,他引:5  
毛敏  黄建滨  肖进新  何煦   《化学学报》2000,58(11):1358-1364
用紫外吸收光谱的方法研究了多种芳香反离子与离子表面活性剂胶团之间的相互作用。发现阳离子表面活性剂和阴离子表面活性剂胶团对芳香反离子的吸收光谱有着显著不同的影响,芳香反离子结构的细微变化可导致光谱特性显著不同。这被解释为阳离子表面活性剂胶团与芳香环之间的阳离子-π相互作用。阳离子-π相互作用需要阳离子表面活性剂分子与芳香反离子具有合适的相对位置与距离。通过测定各混合体系的吸附量证明,不同的芳香反离子在胶团表面有不同的排列方式。NMR的实验结果支持了上述解释。  相似文献   

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