Thermodynamic Studies of Ion Association of s-Acetylthiocholine Halides and Perchlorate in Methanol Solutions

Abstract. Thermodynamic parameters (ΔH 0, ΔG 0, ΔS 0) and the activation energy (ΔEs) were calculated to explain the limiting equivalent conductance (Λ 0) and ion association constant (K A) of s-acetylthiocholine halides and perchlorate in methanol solutions at different temperatures by using conductance measurements. It has been evaluated by using Fuoss-Onsager equation. It is evident that the values of (Λ 0) increase regularly with increase in temperature. For all salts of s-acetylthiocholine, (Λ 0) indicates that higher mobility of the ions in all solvent systems studied. The free energy change ΔG 0 values are negative for all salts (Br − , I − and ClO 4) in solvent systems studied. Clearly strengthening the interionic association at higher temperatures is largely caused by a decrease in the permitivity of the solvent. The positive values of (ΔH 0) for three salts (Br − , I − and ClO 4) show that the association processes are endothermic in nature. Entropy change (ΔS 0) values were positive for all salts because of decrease in solvatio

Sodium diethyldithiocarbamate as accelerator of the rate of copper cementation

The effects of Cu2+ ion concentration and temperature on the cementation rate of copper from copper sulphate on zinc and the effect of additives of the organic compound “sodium diethyldithiocarbamate” (NaDDC) were studied. It was noticed that the cementation increases significantly by increasing the concentrations of NaDDC. The rate of cementation increased by 58.58−100.31%. Our data showed that sodium diethyldithiocarbamate reacts with the Cu2+ solution giving a complex of copper diethyldithiocarbamate, which enhances the rate of cementation