The Thermal Decompositions of Dialkyl Peroxides

Abstract

With the purpose of obtaining information needed for hazard prevention, pure liquid dialkyl peroxides (di-t-butyl peroxide (1), bis(1-methyl-1-phenylethyl) peroxide (2), t-butyl 1-methyl-1-phenylethyl peroxide (3), 2,5-bis(t-butyldioxy)-2,5-dimethylhexane (4)) were subjected to thermal-decomposition experiments, in which thermal analyses were conducted by the use of a thermogravimetry (TG)-differential scanning calorimetry (DSC) apparatus equipped with a pinholed pan with a minute pinhole. From the DSC curves recorded, we obtained the decomposition temperature of Samples 2, 3, and 4, as a constant value for each sample, and the maximum exothermic peaks at the optimum pinhole diameters (0.07–0.2 mm). The heats of decomposition obtained could be considered appropriate, as they roughly agreed with the estimated value, on the other hand, 1 shows no exothermic peak under these condition. Plotting by the Goats-Redfern method based on the TG-curve data (2, 3, and 4) gave reaction orders of more than unity, activation energies of 33–37 kcalth/mol, and frequency factors of 1016–1018 s−1. It is conceivable that these results could be derived by virtue of the TG–DSC curves that were suitable in obtaining thermochemical parameters. In other words, the analysis method introduced in this paper was found to be an efficient one for liquid peroxides that are difficult to analyze by a conventional TG–DSC method.

Mixing hazard evaluation of organic peroxides with other chemicals

“…As all samples except MEKPO were prepared as 70 wt% with liquid paraffin, the thermal decomposition behaviour became mild and less violent than that of original and it was found that dilution had a strong influence on the thermal decomposition of POs (Uetake, 1979).…”