Studies of Thermodynamic Properties of Binary and Ternary Methanolic Solutions Containing KBr and 18-Crown-6 at 298.15 K
Studies of Thermodynamic Properties of Binary and Ternary Methanolic Solutions Containing KBr and 18-Crown-6 at 298.15 K
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含KBr和18-Crown-6的二元和三元甲醇溶液在298.15 K下的热力学性质研究
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发表时间：
2006
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通讯作者：
K. Patil
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作者：
Rahul R. Kolhapurkar;P. K. Patil;D. H. Dagade;K. Patil
实验测定了298.15 K下18-冠-6(18C6)+CH3OH、KBr2+CH3OH和KBr1+18C6+CH3OH三元溶液的声速、密度和渗透蒸汽压，并对密度和可压缩性数据进行了处理，得到了溶质在甲醇中的表观摩尔体积和表观摩尔等熵压缩系数。从不同温度下的密度数据获得了18C6+CH_3OH体系的膨胀率数据，并用于计算298.15 K下的等温压缩系数，进而利用等温压缩系数和膨胀系数数据得到了18C6在甲醇溶液中的表观摩尔压缩系数(PhI_K_T)和表观摩尔膨胀系数(E)以及在甲醇溶液中的能量-体积系数参数(∂U/∂V)T。在无限稀释度下，得到了KBr18C6与18C6络合后的体积和压缩系数的变化，并与我们以前在水溶液和CCl4溶液中得到的类似数据进行了比较。渗透系数数据被用来计算各组分在298.15 K时的活度和活度系数，作为含有KBr和18C6的二元和三元甲醇溶液浓度的函数。活度和活度系数数据被用来通过适当地利用McMillan-Meyer溶液理论来估计对和三重态相互作用参数。用络合平衡的对相互作用参数GNE(非电解质-电解质对相互作用)计算热力学平衡常数(K)。讨论了CH3OH溶液中存在的相互作用的性质。
Experimental measurements of the speed of sound, density and osmotic vapour pressure are reported for binary 18-Crown-6 (18C6) + CH3OH, KBr + CH3OH and ternary KBr + 18C6 + CH3OH solutions at 298.15 K. The density and compressibility data were processed to obtain the apparent molar volume (øV) and apparent molar isentropic compressibility ($$phi _{K_S } $$) of the solutes in methanol. Expansivity data were obtained for the 18C6 + CH3OH system from density data at different temperatures and were used for calculation of the isothermal compressibility values at 298.15 K. The isothermal compressibility and expansivity data are further used to obtain the apparent molar isothermal compressibility ($$phi _{K_T } $$) and apparent molar expansivity (øE) of 18C6 in methanolic solutions and as well as the energy-volume coefficient parameter (∂ U/∂ V)T in methanol solutions. The volume and compressibility changes due to complexation of KBr with 18C6 are obtained at infinite dilution for øV and øK. The results are compared with the similar data obtained by us previously for aqueous and CCl4 solutions. The osmotic coefficient data were used to calculate activities and activity coefficients of each component at 298.15 K as a function of the concentration of binary and ternary methanolic solutions containing KBr and 18C6. The activity and activity coefficient data are used to evaluate the pair and triplet interaction parameters by making appropriate use of the McMillan-Meyer theory of solutions. The calculation of the thermodynamic equilibrium constant (K) is made using the pair interaction parameter, gNE (non-electrolyte – electrolyte pair interaction), for the complexation equilibria. The nature of interactions present in the CH3OH solutions is discussed.