Oxidation of S and SO by O2 in high-temperature pyrolysis and photolysis reaction systems

✍ Scribed by D. Woiki; P. Roth

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 718 KB
• Volume: 27
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550270108

✦ Synopsis

Abstract

The reaction of S atoms with O~2~ was studied behind reflected shock waves applying atomic resonance absorption spectroscopy (ARAS) for concentration measurements of S and O atoms. S atoms were generated either by laser‐flash photolysis (LFP) of CS~2~ or by the high‐temperature pyrolysis of COS, respectively. The concentrations of O~2~ in the mixtures ranged between 50 ppm and 400 ppm, and those of the S precursors, CS~2~ and COS, between 5 and 25 ppm. The rate coefficient of the reaction
equation image
was determined from the observed decay of the S absorption signals for temperatures 1220 K ⩽ T ⩽ 3460 K. The measured O‐atom concentration profiles in COS/O~2~/Ar reaction systems were evaluated, using simplified kinetic mechanism, to verify the given rate coefficient k~5~. In experiments with the highest value of the [O~2~]/[COS] ratio the measured O‐atom concentrations were found to be sensitive to the reaction:
equation image
The fitting of the calculated O‐atom profiles to the measured ones results in mean value of:
which is to be valid for the temperature range 2570 K ⩽ T ⩽ 2980 K.

A first‐order analysis of the observed S absorption decay in LFP shock wave experiments on CS~2~/Ar gas mixtures resulted in a rate coefficient of the background reaction (R4):
equation image
for temperatures 1260 K ⩽ T ⩽ 1820 K. © 1995 John Wiley & Sons, Inc.