Combustion chemistry of Ti(OC3H7)4 in premixed flat burner-stabilized H2/O2/Ar flame at 1 atm

Abstract

The flame structure of the premixed H2/O2/Ar mixture (13%/14.5%/72.5%vol.) with and without 0.12vol.% of titanium tetraisopropoxide (Ti(OC3H7)4) has been studied experimentally using the flame-sampling molecular beam mass-spectrometry and the microthermocouple techniques. The flame was stabilized on a flat burner at 1atm. The temperature and concentration profiles for Н2, О2, H2O, and Ti(OC3H7)4 have been measured. The mass peak intensity profiles of the titanium-containing species TiO2, HTiO2, TiO, HTiO, Ti, TiH, Ti2O3, TiO3 have been measured as well. The experimental results were analyzed using kinetic modeling and quantum chemical calculations. It was established that hydrolysis of Ti(OC3H7)4 is the dominating primary reaction of its decomposition in the flame. The rate constant of hydrolysis was estimated to be k=2×1012exp(−6160/T)mol−1cm3s−1. The results of quantum chemical computations support this conclusion. On the basis of concentration profiles of the Ti-containing intermediates, the schematic mechanism of the Ti(OC3H7)4 conversion in the flame has been proposed.