Collect. Czech. Chem. Commun. 1980, 45, 2300-2307

Thermal effects of dissolution of aluminium halogenides in acetonitrile and tetrahydrofuran

Miriam Gálová and Daniela Kladeková

Department of Chemistry, Institute of Technology, 043 85 Košice


Molar enthalpies of dissolution of aluminium chlorides, bromides, and iodides in acetonitrile and tetrahydrofuran at 295 K have been determined experimentally. results of the measurements carried out in presence of air humidity point to the fact that both solvents preferential solvation of the solute by water molecules takes place. In an inert atmosphere, all the values obtained are negative. molar heat of dissolution has for AlCl3 the lowest negative value: -181 kJ mol-1 in acetonitrile and -107.8 kJ mol-1 in tetrahydrofuran. For AlBr3 and AlI3 exothermicity of dissolution is considerably higher: -817 and -887 kJ mol-1 for acetonitrile, and -489 and -713 kJ mol-1 for tetrahydrofuran. The transfer from water into both organic solvents has an endothermic character for AlCl3 only; for AlBr3 and AlI3, the character of transfer is unambiguously exothermic. The obtained results are interpreted as effects of interaction between the solute and the solvent.