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Introduction Thermal properties of tetraalkylammonium (TAA) salt solutions in non-aqueous binary solvents containing formamide were studied in set of the works [ 1 – 4 ]. In the article [ 1 ], the enthalpies of solution of

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Abstract  

The heat effects of the reactions of formation of ethylenediamine-copper(II) complexes were determined calorimetrically in mixtures of water with ethanol, acetone and dimethylsulfoxide. The results were interpreted in terms of the enthalpies of transfer (Δt H 0) of the complex former, the ligand and the complex ion from water to binary solvents. In water—DMSO mixtures, the Δt H 0 values for copper(II) and complex ions were found to change in similar ways, and their contributions to the reaction heat effects compensate each other to a large extent. Thus, the reaction enthalpy change due to solvent composition variation is caused mainly by the changes in ligand solvation enthalpies. In aqueous ethanol and acetone solutions, the changes in Δt H 0 for all reagents influence the heat effect equally.

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Abstract  

The heats of solution of tetrabutylammonium bromide have been measured in mixtures of formamide (FA) with methanol (MeOH) and ethylene glycol (EG) at 313.15 K by calorimetric method. The standard enthalpies of solution in binary mixtures have been extrapolated to infinite dilution by Redlich–Rosenfeld–Meyer type equation using the literary data at 298.15 K and the present paper data at 313.15 K. The Debye–Hückel limiting law slope A H required for calculation of the ∆sol H 0 value has been obtained with application the new additive scheme of determination of the physic-chemical characteristics of binaries. The scheme is tested on the example of Bu4NBr solutions in FA–MeOH mixture at 298.15 K. Its application yields the ∆sol H 0 value very closed on the ones determined with the real (non-additive) characteristics of binaries. The standard enthalpies of solution extrapolated by Redlich–Rosenfeld–Meyer type equation are in a good agreement with the ones computed in terms of the Debye–Hückel theory in the second approximation. The heat capacities characteristics of Bu4NBr have been calculated in H2O–FA, MeOH–FA and EG–FA mixtures using the literary and present data. The sequence of solvents H2O > FA > EG > MeOH located on their ability to solvophobic solvation found by us earlier for enthalpic characteristics is confirmed by the ∆C p 0 values. The comparison of thermochemical characteristics of Bu4NBr solutions in aqueous and non-aqueous mixtures containing FA has been carried out. The own structure of water remains in the region of small additions of formamide to co-solvents. It considerably differs the H2O–FA mixture from the investigated non-aqueous systems.

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Abstract  

The complex formation of Ag+ with polyether 18-crown-6 (18C6) and their solvation have been studied using calorimetric and potentiometric methods in H2O-EtOH solvents in wide range of ethanol concentration. The standard enthalpies of dissolution AgNO3, AgClO4 and 18C6 in aqueous-ethanol solvents are obtained. The stability of a complex [Ag18C6]+ grows with increasing the EtOH content a solvent. Using the method based on the thermodynamic characteristics of solvation of metal-ion, ligand and complex-ion the interpretation of the results has been given.

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arenesulfonates, we planned to focus on the solvation effect. Herein, an investigation concerning the analysis of reaction rate and thermodynamic parameters in the reaction of phenyl magnesium bromide with phenyl tosylate in THF:toluene binary solvents and in

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Progress in Agricultural Engineering Sciences
Authors: Szilvia Bánvölgyi, Eszter Dusza, Fiina K. Namukwambi, István Kiss, Éva Stefanovits-Bányai, and Gyula Vatai

rate of many compounds resulting higher extraction rate in phenolic compounds ( Şahin et al., 2013 ). In both cases the binary solvent (1:1) was better than mono-solvent. According to the model the total polyphenol content in the extracts is predicted

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.W. & Tan , C.P. ( 2010 ): Effects of binary solvent extraction system, extraction time and extraction temperature on phenolic antioxidants and antioxidant capacity from mengkudu (Morinda citrifolia) . Food Chem., 120 , 290 – 295

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, V. & S yed , W.H. ( 2013 ): Novel binary solvents-dispersive liquid-liquid microextraction (BS-DLLME) method for determination of patulin in apple juice using high-performance liquid chromatography . Food Anal. Method , 6 , 761 – 766

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from the standard dissolution enthalpy, Δ sol H ° according to the formula: For the description of solutions in binary solvents, the enthalpy of transfer, Δ tr H °, of the solute from an individual solvent (S) to the mixed solvent (M) of various

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-9614(73)80073-4 . 5. Korolev VP , Antonova OA , Smirnova NL , Kustov AV . Thermochemistry of Bu 4 NBr solutions in binary solvents containing formamide . J Therm Anal Calorim. 2009 ; 96 : 903 – 10 . doi: 10

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