فهرست نشریات علمی دسترسی آزاد ایران

In recent years, ionic liquids have been used in pharmaceutical processes. Therefore, having a deep insight into the ion association behavior of ionic liquids in the presence of a drug is of particular importance. So, in this work, the molar conductivities of the ionic liquids, 1-alkyl-3-methylimidazolium bromide, [C n MIm]Br (n = 4, 6 and 8) in various concentrations of aspirin (ASA) in acetonitrile (MeCN) solutions are determined in very diluted region of ILs, (molality less than 0.01 mol kg -1 ) and at 298.15 K. The obtained conductivity data were analyzed by low concentration Chemical Model (lcCM) of conductance equation. Using this model the limiting molar conductivities (L 0 ) and ion association constants ( K A ) were calculated. The results show that the L 0 and K A values of ionic liquid are affected by the alkyl chain length of cation and the concentration of ASA. The values of L 0 and K A decrease as the alkyl chain length of cation and ASA concentration increase. The K A was also used to calculate the standard Gibbs energy ( ) of ion-pairing association. In general,              1-butyl-3-methylimidazolium bromide, [BMIM]Br, has the low values of ion-pair formation and the high negative values of and stronger interaction between [BMIM]Br and ASA.