High-temperature decomposition of TiCl 4 based on Cl-concentration measurements

Abstract

The thermal decomposition of TiCl4 was studied behind reflected shock waves at temperatures 1300 K≤T≤1500 K at pressures between 1.3 and 3.7 bar. Atomic resonance absorption spectroscopy (ARAS) was applied for time-resolved measurements of Cl atoms in gas mixtures containing 0.2–45 ppm TiCl4 high diluted in argon. The signals obtained were kinetically evaluated by computer simulation based on a simplified reaction mechanism. The very sensitive Cl-ARAS technique allowed us to choose reaction conditions under which the Cl profiles were almost only dependent on the rate coefficients k1 and k2 of the following reactions: T i C l 4 + M ↔ T i C l 3 + C l + M ( R 1 ) T i C l 3 + M ↔ T i C l 2 + C l + M ( R 2 ) k 1 = 10 18.73 ± 0.35 exp ⁡ ( − 40 , 370 ± 1120 K / T ) c m 3 m o l − 1 s − 1 k 2 = 10 18.05 ± 0.28 exp ⁡ ( − 46 , 500 ± 1260 K / T ) c m 3 m o l − 1 s − 1 . Within our experimental uncertainty, we found no falloff effects.