The pyrolysis of tertiarybutanol and diethylzinc has been studied, separately as well as combined, using an isothermal reactor attached to a quadrupole mass spectrometer. Kinetics of decomposition under hydrogen atmosphere were investigated over the temperature range 200-500 degrees C, and reaction mechanisms are finally proposed. The decomposition of diethylzinc was found to be in agreement with previous studies. It starts above 300 degrees C and leads to the formation of ethylene (C2H4) and ethane (C2H6). The pyrolysis of tertiarybutanol begins at higher temperature, 360 degrees C, and produces water (H2O) and isobutene (C4H8). In case of the co-pyrolysis of tertiarybutanol with diethylzinc, these same decomposition products appear, indicating a comparable chemical process. It was observed that the onset and the complete decomposition were shifted to lower temperatures. The shift is 30 degrees C for tBuOH and 50 degrees C for DEZn. A ZnO deposit on the reactor walls was also found to influence the pyrolysis. (C) 2008 Elsevier B.V. All rights reserved.