Kinetic mechanism of the decomposition of dimethyltin dichloride

Results are reported of a study of the intrinsic kinetics of gas phase reactions. For this purpose a reactor system is designed in such a way that concentration and temperature variations throughout the reactor can be neglected enabling investigation of intrinsic reaction kinetics. The gas phase composition in the reactor is analysed by Fourier Transform Infrared spectroscopy and Mass spectrometry. Investigation of the pyrolysis of dimethyltin dichloride (DMTC) in nitrogen between 370 and 630°C with this system revealed that decomposition starts at 500°C. A linear relationship has been found between the formation of methane, ethane, ethene, and propane and the inlet concentration of DMTC. Also the overall decomposition rate is first order in inlet concentration of DMTC. Linear least squares analysis gives a rate constant with an Arrhenius constant of 9±11015 s-1 and an activation energy of 62.8±3 kcal/mol. A mechanism is proposed that describes all the observations.