THERMOANALYTICAL STUDIES ON CROWN-ETHER ALKALI COMPLEXES

Solid samples prepared from benzo-15-crown-5, its nitro, acetylamino a nd decanoylamino derivatives (Group I), and chloro-dibenzo-aza-crown e thers (Group II) with alkali metal salts were studied. The existence o f solid adducts between LiBr, NaSCN, KSCN and crown ethers of group I was proved by DSC. The melting points of adducts of the same ligand we re found to increase in KSCN<NaSCN<LiBr order. DSC and TG results sugg ested a ligand scission mechanism of thermal decomposition for all the complexes except that of benzo-15-crown-5 and KSCN where a dissociati on and evaporation process took place. The samples prepared from crown ethers belonging to group II were found to be mechanical mixtures of the alkali salts and crown compounds. (C) 1998 Elsevier Science B.V.