Theoretical and experimental investigations of the decomposition of 10-methylacridinium halides

10-Methylacridinium chloride, bromide and iodide were prepared in crystalli ne forms (the first two salts as monohydrates) and subjected to thermogravi metric investigations. Decomposition of the compounds is initially accompan ied by the liberation of water (in case of monohydrates), halomethanes and acridine molecules. As decomposition proceeds, side reactions occur which a re reflected in a complex pattern of thermogravimetric curves. TG traces co rresponding to the initial decomposition stage were used to determine the k inetic characteristics of the thermal dissociation of the salts. MNDO/d, AM 1 and PM3 methods were employed independently to examine reaction pathways and to predict thermodynamic and kinetic barriers for the thermal decomposi tion of the compounds. These data were subsequently supplemented with theor etically determined crystal lattice energies, which enabled the relevant ch aracteristics for the decomposition of crystalline phases to be predicted. The theoretically predicted characteristics are qualitatively comparable wi th those originating from thermogravimetric investigations, which allows on e to believe that both are valid.