SciELO Mexico - www.scielo.org.mx

Links

The values of ΔH⁰, ΔG⁰, ΔS⁰ are recorded in Tables 1, 2 and 3. For s-acetylthiocholine bromide, iodide and perchlorate in methanol at different temperatures (25, 30, 35 and 40 °C). (ΔG⁰) values decrease with increase in temperature. The decrease in (ΔG⁰) values for the (three salts) to more negative values at increasing temperature favors the transfer of the released solvent molecules into bulk solvent and leads to a smaller (ΔG⁰) values. It was observed that (ΔH⁰) values decrease in the order: I^- > Br^- > ClO₄^-. The (ΔH⁰) values were found to be positive in all alcohols. Positive and high (ΔH⁰) values can be attributed to the interaction between ions [8]. As presented in (Tables 1-3)(2) (ΔS⁰) values were positive because of decrease in the solvation of ion-pair compared to that of the free ion [2, 9, 10]. This may be attributed to increase in the degree of freedom upon association, mainly due to the release of solvent molecules.