Shock tube study of monomethylamine thermal decomposition and NH2 high temperature absorption coefficient

CH3NH2 thermal decomposition is shown to provide a suitable NH2 radical sou rce for spectroscopic and kinetic shock tube studies. Using this precursor, the absorption coefficient of the NH2 radical at a detection wavelength of 16739.90 cm(-1) has been determined. In the temperature range 1600-2000K t he low-pressure absorption coefficient is described by the polynominal equa tion: k(NH2) = 3.953 10(10)/T-3 + 7.295 X 10(5)/T-2 - 1.549 X 10(3)/T ([atm-1 cm- 1]) The uncertainty of the determined absorption coefficient is estimated to be +/-10%. The rate of the thermal decomposition reaction CH3NH2 + M --> CH3 + NH2 + M is determined over the temperature range 1550-1900 K and at pressures near 1.6 atm. The rate coefficient was found to be: k(1) = 2.51 x 10(16) exp(-28430/T) [cm(3) mol(-1) s(-1)] The uncertainty of the determined rate coefficients is estimated to be +/-2 0%. (C) 1999 John Wiley & Sons. Inc.