Thermal decomposition of sodium propoxides

Sodium alkoxides, namely, sodium n-propoxide and sodium iso-propoxide were synthesized and characterized by various analytical techniques. Thermal decomposition of these compounds was studied under isothermal and non-isothermal conditions using a thermogravimetric analyzer coupled with mass spectrometer. The onset temperatures of decomposition of sodium n-propoxide and sodium iso-propoxide were found to be 590 and 545 K, respectively. These sodium alkoxides form gaseous products of saturated and unsaturated hydrocarbons and leave sodium carbonate, sodium hydroxide, and free carbon as the decomposition residue. Activation energy, E _a, and pre-exponential factor, A, for the decomposition reactions were deduced from the TG data by model-free (iso-conversion) method. The E _a for the decomposition of sodium n-propoxide and sodium iso-propoxide, derived from isothermal experiments are 162.2 ± 3.1 and 141.7 ± 5.3 kJ mol^?1, respectively. The values obtained from the non-isothermal experiments are 147.7 ± 6.8 and 133.6 ± 4.1 kJ mol^?1, respectively, for the decomposition of sodium n-propoxide and sodium iso-propoxide.