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Excess heat of mixing of pyridine bases with toluene

Experimental results and theoretical description

Journal of Thermal Analysis and Calorimetry
Authors: H. Wilczura, T. Kasprzycka-Guttman, and A. Myslinski

Abstract  

The excess heats of mixing of pyridine bases with toluene at 298.15 K were measured, and the Prigogine-Flory-Patterson theory was applied to describe the experimental results.

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Excess heat of mixing of α-picoline withn-alkanes

Comparison with the Prigogine-Flory-Patterson theory and the extended real associated solution method

Journal of Thermal Analysis and Calorimetry
Authors: T. Kasprzycka-Guttman, H. Wilczura, and A. Myslinski
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The molar excess enthalpies of binary mixtures of pyridine with C6–C9 n-alkanes have been measured at 313.15 K in the entire composition range. The measuredH E values were compared with those calculated by means of the Prigogine-Flory-Patterson theory and by the ERAS method.

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Abstract  

The 'extremely diluted solutions', anomalous solutions prepared through the iteration of a process of dilution and succussion, have been studied with the aim of obtaining information about the influence of the preparation method on the water structure of the solutions. We measured the heats of mixing of basic solutions with such 'extremely diluted solutions', and their electrical conductivity, comparing with the analogous heats of mixing, electrical conductivity of the solvent. We found some relevant exothermic excess heats of mixing, and higher conductivity than those of the untreated solvent. The heats of mixing and electrical conductivity show a good correlation, underlining a single cause for the behaviour of the extremely diluted solutions.

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Abstract  

An extensive thermodynamic study has been carried out on aqueous solutions, obtained through the iteration of two processes: a dilution 1:100 in mass and a succussion. The iteration is repeated until extreme dilutions are reached (less than 1⋅10–5 mol kg–1 ) to the point that we may call the resulting solution an 'extremely diluted solution'. We conducted a calorimetric study, at 25C, of the interaction of those solutions with acids or bases. Namely, we measured the heats of mixing of acid or basic solutions with bidistilled water and compared them with the analogous heats of mixing obtained using the 'extremely diluted solutions'. Despite the extreme dilution of the latter solutions, we found a relevant exothermic excess heat of mixing, excess with respects to the corresponding heat of mixing with the untreated solvent. Such an excess has been found in about the totality of measurements, and of a magnitude being well beyond one that could arise any issue of sensibility of the instrumental apparatus. Here we thus show that successive dilutions and succussions can permanently alter the physico-chemical properties of the solvent water. The nature of the phenomena here described still remains unexplained, nevertheless some significant experimental results were obtained.

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Abstract  

An extensive study has been carried out on extremely diluted aqueous solutions (EDS). These solutions revealed a really intriguing physico-chemical behaviour, characterized by multiple independent variables. Because of their behaviour, EDS can be described as far-from-equilibrium systems, capable of self-organization as a consequence of little perturbations. In this paper we investigate the stability of the calorimetric behaviour of EDS with a high ionic force, due to the presence of the sodium chloride electrolyte. We measured the excess heats of mixing of EDS with basic solutions, both with and without a high concentration of NaCl, and compared the results. In particular, we explored these concentrations: 0.5 and 1Mmol kg−1). The analysis of the experimental results shows that the calorimetric response of the EDS is stable when they are in a concentrated solution of NaCl. That is of great relevance for the eventual pharmacological action of these solutions, since it involves the interaction with fluids of complex chemical composition and high concentration.

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Abstract  

The extremely diluted solutions are anomalous solutions obtained through the iteration of two processes: a dilution 1:100 in mass and a succussion. The iteration is repeated until extreme dilutions are reached (less than 110-5mol kg-1) to the point that we may call the resulting solution an extremely diluted solution, namely the composition of the solution is identical to that of the solvent used (e.g. twice distilled water). We conducted thermodynamic and transport measurements of the solutions and of the interaction of those solutions with acids or bases. The purpose of this study is to obtain information about the influence of successive dilutions and succussions on the water structure of the solutions under study. We measured the heats of mixing of acid or basic solutions with such extremely diluted solutions, their electrical conductivity and pH, comparing with the analogous heats of mixing, electrical conductivity and pH of the solvent. We found some relevant exothermic excess heats of mixing, higher electrical conductivity and pH than those of the untreated solvent. The measurements show a good correlation between independent physico-chemical parameters. Care was taken to take into account the effect of chemical impurities deriving from the glass containers. Here we thus show that successive dilutions and succussions can permanently alter the physico-chemical properties of the water solvent. The nature of the phenomena here described still remains unexplained, nevertheless some significant experimental results were obtained.

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Journal of Thermal Analysis and Calorimetry
Authors: G. Giannini, F. Cuppo, L. Fontanive, N. D'Amelio, A. Cesàro, A. Maiocchi, and F. Uggeri

Figure 5 shows heat of dilution data plotted against the concentration of iomeprol and reports data of iopamidol and iomeprol at 25 °C already calculated. The linearity of plot of Fig. 5 suggests that the excess heat of mixing ( h ij in the notation

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