Štúdium vplyvu chloridov a bromidov na kritickú micelovú koncentráciu a parciálny mólový objem kvartérnej amóniovej soli

The critical micelle concentration (CMC) of the selected surfactant belonging to quaternary ammonium salts with chemical designation N,N-dimethyl-N-(3-((1R,5S)-1,8,8-trimethyl-2,4-dioxo-3-azabicyclo[3.2.1]octane-3yl)propyl)hexadecane-1-amine bromide was determined. Simultaneously, the effect of the addition of various concentrations of NaCl, KCl, NaBr, and KBr salts on the CMC value of the substance was observed and compared with those obtained in an aqueous solution at T = 296,15 K. Based on the results obtained, it was concluded that NaCl and KCl salts decreased the critical micelle concentration, while NaBr and KBr salts did not support micellization and CMC values therefore increased. In the case of solutions of a substance in the salt environment, when compared to the substance's solution in distilled water, a decrease in partial molar volume was observed. From the concentration density dependencies of the substance, an ionization degree of α was determined. Finally, the molar Gibbs energy ∆G° was also calculated and found negative for all salt solutions, while increase with their increasing concentration.

The Establishment of Thermodynamic Model for Ti Bearing Steel-Slag Reaction and Discuss

A thermodynamic model for seven CaO-MgO-BaO-CaF2-SiO2-Al2O3-TiO2 ladle slags based on the Ion and Molecule Coexistence theory (IMCT) is establishment and validated by the experiment results at 1873K. The calculated activity of SiO2, Al2O3 and TiO2 in the slag can be approved by the experiment results and the IMCT model used in this study is reasonable. Then the influence factors such as the mass ratio of CaO to SiO2 (C/S ratio) ranging from 1 to 10, the mass ratio of CaO to Al2O3 (C/A ratio) ranging from 1 to 2.5, TiO2 content (wt pct) ranging from 0 to 30, BaO content (wt pct) ranging from 0 to 30 are investigated based on the thermodynamic calculating results. The raise of C/S ratio, TiO2 content and BaO content in the slag can increase the molar Gibbs energy change (ΔG) of Ti reacted with SiO2 and Al2O3 or Al reacted with SiO2. The effect of C/A ratio on the molar Gibbs energy change (ΔG) of Ti reacted with SiO2 and Al2O3 or Al reacted with SiO2 was less. Finally, the slag with higher C/S ratio and TiO2 content and appropriate BaO content can weaken the reaction between Ti and SiO2 or Al2O3 in the slag.

Densities, Viscosities and Excess Properties of Binary Mixtures of 2-Methoxy-2-methylpropane with iso-Propanol

Densities (r) and viscosities (h) of the binary systems 2-Methoxy-2-methylpropane with iso-propanol were measured at temperatures (288.15, 293.15, 298.15, 303.15 and 308.15) K and atmospheric pressure, over the whole composition range. The density and viscosity of the solutions were correlated with the temperature with a linear equation, respectively with Guzman�s equation. The excess values of molar volume (VE), viscosity (hE) and molar Gibbs energy (DG*E) were calculated from experimental measurements. The excess functions of the binary systems were fitted to Redlich-Kister equation. Viscosity results were fitted to the equations of Grunberg-Nissan, Heric-Brewer, Jouyban-Acree and McAllister.

EFFECT OF PRESSURE ON EXCESS THERMODYNAMIC CHARACTERISTICS OF WATER + FORMAMIDE MIXTURE

Using the experimental data on the densities at atmospheric pressure and compressibility coefficients, k=(Vo-V)/Vo, of water + FA mixture the changes in the following thermodynamic parameters were calculated under the pressure increase up to 100 MPa within the temperature range from 288.15 to 323.15 K: excess molar Gibbs energy, ΔPo→PGmE, excess molar entropy ,ΔPo→PSmE, and excess molar entropy ΔPo→PHmE. It was established that ΔPo→PGmEvalues were negative over the whole concentration range and minima appeared on ΔPo→PGmE= f(x2) functions at x2≈0.33. The pressure growth up to 100 MPa resulted in ΔPo→PGmE absolute values increase within entire concentration and temperature intervals. The changes in entropy component, -(ΔPo→PTSmE), of ΔPo→PGmEvalues were almost canceled by the enthalpy component changes. Minimal values of ΔPo→PSmE corresponded to x2≈ 0.33, exactly at that composition 2Н2О-FA associate formed. The isobaric temperature lowering caused the structure ordering also at x2≈ 0.33. The pressure growth promoted the increasing in exothermicity of the mixing enthalpies, HmE, of water and formamide. The changes in HmE value under the mixture compression are indicative of the larger exothermal contribution from new H-bonds formation as compared with the endothermic contribution from the decreasing in the total amount of hydrogen bonds. The temperature lowering decreases ΔPo→PHmEvalues as well; maximal isotherms dispersion is observed at concentrations corresponding to maximal content of 2:1 or 1:1 associates of water and FA.