The oxidative thermal stability of two series of thirteen model compounds Ⅰ-XIII containing benzothiazole

benzoxazole

benzimidozole

phthalimide

benzoxazinone and quinoxaline ring was measured:The results indicated that the order of oxidative thermal stability of these two series of model compounds arc Ⅰ > Ⅱ Ⅶ

Ⅳ

Ⅵ > Ⅲ > Ⅴ and Ⅷ > Ⅸ > Ⅺ > XIII

Ⅻ > Ⅹ

respectively. Compound with benzothiazole ring possesses the best oxidative thermal stability

and the next is that with benzoxazole ring

then that with phthalimide ring

The oxiative thermal stability of compounds with teh other three heterocyclic ring is not so good.