Thermal decomposition of strontium and barium malonates

The thermal decomposition of strontium and barium malonates has been studie d isothermally and non-isothermally employing simultaneous TG-DTG-DTA, DSC, XRD and IR spectroscopic techniques. DSC of these malonates has been recor ded both in oxygen and nitrogen atmospheres. The decomposition is a single step process and the end product formed is carbonate. The energy of activat ion and frequency factor values for the decomposition of strontium malonate are 547 kJ mol(-1) and 10(41) s(-1) respectively. The activation energy an d frequency factor values for isothermal dehydration of barium malonate ses ter-hydrate are 57-111 kJ mol(-1) and 10(7)-10(12) s(-1) respectively and t he corresponding values for decomposition from DSC are 499.5 kJ mol(-1) and 10(44) s(-1) respectively. The higher thermal stability of strontium malon ate as compared to that of barium salt is ascribed to its being anhydrous s o that decomposition proceeds without restructuring. Their thermal stabilit ies have also been compared with that of respective oxalate salts.