Abstract:

A ternary complex with the formula of [Dy(p-MBA)3phen]2(p-MBA=p-methylbenzoic acid; phen=1,10-phenathroline) was synthesized via the solution method. Elemental analysis, infrared spectra, molar conductance, thermogravimetry and derivative thermogravimetry(TG-DTG) were used to characterize the title complex. The results show the Dy(Ⅲ) ion was coordinated to the oxygen atoms of p-methylbenzoic acid, and the nitrogen atoms of the 1,10-phenanthroline, and the title complex has a good thermal stability. Non-isothermal kinetics of the first thermal decomposition stage of Dy(Ⅲ) complex was studied in the static air atmosphere. Through the Popescu method and the nonlinear integral isoconversional(NL-INT) method, the kinetic equation was expressed as dα/dT=(15.55×1012/β)exp(-19825.60/T)3(1-α)2/3, and the average activation energy and the pre-exponential factor were 164.83 kJ/mol and 15.55×1012 min-1, respectively. The thermal stability of a series of complexes was compared. The results may provide some valuable materials for the choice of functional materials of rare-earth complexes.

Key words: Dysprosium complex, p-methylbenzoic acid, phenanthroline, non-isothermal kinetics