High temperature measurements of the rate of the reaction of OH with NH3

✍ Scribed by M. F. Zabielski; D. J. Seery

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 368 KB
• Volume: 17
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550171105

✦ Synopsis

Low pressure (4.67 kPa) CiI,/02/Ar flames were seeaed with approximately 5300 ppm NH,. The concentration profiles of stable and radical species in lean (6 = 0.92) and rich (r#~ = 1.13) flames were determined by molecular beam sampling mass spectrometry. Temperature profiles in these flames were measured with thermocouples whose readings were corrected for radiative losses by the Na-line reversal method. Regions of the flames were selected where the principal reaction leading to the destruction of NH3 was (1) NH, + OH + NH2 + H 2 0 By correcting the measured concentrations for diffusion, the net rate of NH, loss rate was determined in the temperature range 2080-2360 K. The rate constant k , was determined from the net loss rate with correction for the reaction (2) N H , + O -+ N H , + O H using measured values of (0) and k 2 values given by Salimian, Hanson, and Kruger 111. The best-fit Arrhenius expression for k l in the temperature range 2080-2360 K is 1013.88 exp(-4539/T) cm3/mol-s. The results of this study combined with previous lower temperature data confirm the non-Arrhenius behavior of k l suggested by Salimian, Hanson, and Kruger [l]. The best-fit modified three parameter expression for the range 300-2360 K is T2 exp(-169/T) cm'/mol-s.