تكوين المزدوجات الايونية لاملاح رباعي الكيل امونيوم بروميد في أمزجة هيدروكسي بروبيل مثيل سيليلوز- ماء في درجات حرارية مختلفة

Ion-pair Formation of Tetraalkylammonium Bromide in Hydroxy Propyl methyl Cellulose-Water Mixtures at Different Temperatures

This thesis involved the study of ion-pair formation of Tetralkylammonium Bromide in three weight percentages of Hydroxypropylmethyl cellulose (HPMC)-water mixtures (0.1%, 0.2% and 0.3%) at six temperatures i.e. (293.15, 298.15, 303.15, 308.15, 313.15, 318.15) K by using deionized water with specific conductance 5×10^-7 Scm^-1 at 298.15K which:

The physical properties of mixed solvents were studying which covered the measurements of densities (d), viscosities (ɳ), dielectric constants (ε) and specific conductances (σ) for the solvent mixtures at specific temperatures from this data. The deviation of solvent mixtures from an ideal behavior was studies by the excess molar volume (), excess dielectric constant (ε^E) and temperature dependence of viscosity which can estimated that activation energy for ion flow (E) and explained the interaction between solvent systems. The physical properties of Tetramethylammonium Bromide (TMAB) and Tetraethylammonium Bromide (TEAB) were studying for nine concentrations for each three wt% of HPMC-water mixture at six experimental temperatures covered densities (d), viscosities (ɳ) and molar conductances (Λ) and it were compared between the two salts. Jones-Dole equation was applied to determine A and B there coefficients, where A values indicate that there is a weak solute-solute interaction in the systems and B-coefficient indicates a good solvation of solute-solvent interaction. Association constant (K_A) was calculated by using Bjerrum equation according to estimate the ion-size parameter (å).  The association constant (K_A) and limiting molar conductance (Λ₀) was calculated from a set of equations of Shedlovsky method by using an appropriate computation program. The obtained results give a good agreement between the values of K_A which have been derived from Bjerrum equation and those obtained by Shedlovsky method. These data used to study the relation between limiting molar conductance (Λ₀) and temperatures to estimate the activation energy of free ions(E), the effective radius (r _i), limiting ionic conductance (λᵒ+) and obtain values of the Walden product (W) which reflect the weak ionic interaction and higher conductivity consolidate the higher mobility of free ions. It was calculate the thermodynamics quantities ΔG˚, ΔS˚ and ΔH˚ for these processes from (K_A) values which were used to known that non-feasibility of the ion pair formation process in these electrolytic solutions.