Thermal Instability of Benzoyl Peroxide

Abstract

The thermal unstableness of benzoyl peroxide (BPO) was investigated by means of pressure vessel test (PVT), ignition delay time, TG and DSC methods. ln addition, the analyses of thermal decomposition products and their reactions were carried out.
The PVT curves showed that BPO decomposed violently at about 1000C with the evolution of white smoke, and hence the hazard of this material is very large. The white smoke produced was found by IR analysis to be composed of benzoic acid, phenyl benzoate, terphenyls and biphenyl. The melting point and the decomposion temperature of BPO were dependent.upon heating rate, and the 50C/min was suitable to get the melting point of 105.5A-tlO7 C and the decomposition temperature of 108eC. The ignition delay time depended upon the amount of saMple, and the qnantity of 150 mg was used. lt was found by TG, DSC, IR and the activation energy estimated from ignition delay time that the termal decomposition of BPO at first occured suddenly and followed by a milder reaction. The analysis of IR, thi'n layer chromatography and the pyrolysis gas chromatography revealed that the thermal decomposition of the pure BPO gave carbon dioxide, benzoic acid and biphenyl as main products, together with some phenyl benzoate, benzene and terphenyls. After about 6 to 10%e weight less was perceived on TG curves, this decomposition reaction was accelerated by biphenyl whieh was produced by the decompositi6n of BPO.