Rate constants of CH4+M=CH3+H+M and CH3OH+M=CH3+OH+M over 1400-2500 K

Rate constant k(1) of CH4 + M=CH3 + H + M was determined from time profiles of IR emission at 3.4 mu m obtained for a CH4/Ar mixture heated by inciden t shock waves at pressures 0.40-0.82 atm and temperatures 1400-2500 K. The emission decrease due to CH4 decay in a very short period at the shockfront was investigated. Computer modeling for the decrease gave the k(1) value a s: 3.0 x 10(16) exp(-81.0 kcal/RT) cm(3) mol(-1) s(-1). The k(1) value was almost the same as those reported by all authors except for the report by K lemm et at. The same technique was used for determining the rate constant k (2) of CH3OH + M=CH3 + OH + M and a new value was proposed as k(2) = 4.2 x 10(16) exp(-66.8 kcal/RT) cm(3) mol(-1) s(-1). (C) 2000 John Wiley & Sons, Inc.