Activation of the decomposition of tert-butyl peroxypivalate with trialkylaluminium compounds

The decomposition of tert-butyl peroxypivalate (TBPPI) in the presence of trialkylaluminium activators was examined in an optical cell using in-situ Raman spectroscopy. The measurements were carried out in the temperature range between 90 and 165 degrees C at pressures between 1 and 1800 bar. The trialkylaluminium compounds used were triethyl, trihexyl, trioctyl and tridodecylaluminium which were employed in quantitative ratios of up to 1 mol trialkylaluminium per mol peroxide. From the graphs showing the peroxide concentration as a function of time, the rate constant, the energy of activation and the half-life time of the decomposition reaction were determined. A comparison of these data with the parameters of the decomposition of pure TBPPI in solution clearly illustrated the acceleration of the decomposition reaction as a result of the influence of the organoaluminium compound. By means of the NMR spectra of the individual components and their mixture it was possible to show that the activated decomposition takes place via trialkylaluminium/peroxide complexes.