The decomposition of tert.-butyl hydroperoxide studied by differential scanning calorimetry.

Due to the investigation the oxidation of isobutane to t-butyl hydroperoxide (TBHP), studied for the first time as a two-phase process in a micro reactor at high temperatures and pressures, the prevention of the decomposition of TBHP was crucial. The observed by-products t butyl per-oxide, tert.butanol, acetone, and methanol decreasing the selectivity and thus the TBHP yield are due to the thermal decomposition of TBHP, which is influenced by the wall effect to a large extend. Therefore, the decomposition of TBHP has been studied by Differential Scanning Calorimetry (DSC) at higher temperatures using for the first time different crucible types, pressure conditions, heating rates etc.. Aluminium (low pressure) crucibles, medium pressure crucibles and differently coated high pressure stainless steel crucibles (uncoated, gilded, silicon coated) have been utilized to show the influence of the crucible material as well as of the pressure on the DSC curve. It has been found that the material of the blowout disk has an important influence on the thermal decomposition behaviour. Therefore, within further DSC studies, the sample has been protected against the gilded copper blowout disk by aluminium foil in the crucible. Kinetics of the decomposition reactions has been investigated experimentally by evaluation of the DSC curves using an nth order approach and by a model free kinetics (MFK) approach.