Shock tube measurements of the reactions of CN with O and O2

✍ Scribed by D. F. Davidson; A. J. Dean; M. D. Dirosa; R. K. Hanson

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 903 KB
• Volume: 23
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550231107

✦ Synopsis

The rate coefficients of the reactions (1) and CN + 0 -GO + N

(2) CN + 0 2 -NCO + 0 were determined in a series of shock tube experiments from CN time histories recorded using a narrow-linewidth cw laser absorption technique. The ring dye laser source generated 388.44 nm radiation corresponding to the CN B2H+(u = 0) + X2H+(v = 0) P-branch bandhead, enabling 0.1 ppm detection sensitivity.

Reaction (1) was measured in shock-heated gas mixtures of typically 200 ppm N20 and 10 ppm CzNz in argon in the temperature range 3000 to 4500 K and at pressures between 0.45 and 0.90 atm. k l was determined using pseudo-first order kinetics and was found to be 7.7 x 1013 (-t20%) [cm3 mol-' s-'1. This value is significantly higher than reported by earlier workers. Reaction (2) was measured in two regimes. In the first, nominal gas mixtures of 500 ppm 0 2 and 10 ppm CzNz in argon were shock heated in the temperature range 2700 K to 3800 K and at pressures between 0.62 and 1.05 atm. k2 was determined by fitting the measured CN profiles with a detailed mechanism. In the second regime, gas mixtures of 500 ppm 0 2 and 1000 ppm C2N2 in argon were shock heated in the temperature range 1550 to 1950 K and at pressures between 1.19 and 1.57 atm. Using pulsed radiation from a n ArF excimer laser at 193 nm, a fraction of the C2N2 was photolyzed to produce CN. Pseudo-first order kinetics were used to determine k z . Combining the results from both regimes, kz was found to be 1.0 x 1013 (-t20%) [cm3 mol-' s-l].