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• Direct Measurements of the Reaction NH2+ H2→ NH3+ H at Temperatures from 1360 to 2130K

G. Friedrichs and H.Gg. Wagner
Z. Phys. Chem. 214, 1151-1160 (2000)

 

The reaction NH2+H2→NH3+H (11) was investigated behind shock waves in the temperature range from 1360 to 2130K. Time histories of NH2 were measured by frequency modulation (FM) spectroscopy. The rate constant was determined to be

k11 = 4.5E13·exp(-61 kJ/mol/RT) cm3/mols (Δlog k11=±0.15, ΔEa=±9 kJ/mol)

According to recent literature values the reverse reaction NH3+H→NH2+H2 (-11) can be described by

k-11 = 1.5E7·T2.0·exp(-47 kJ/mol/RT) cm3/mols

for the temperature range of 400 to 2500K. On the basis of k_-11 and by using the enthalpy of formation of Δ_f_H_o_298K = 190 kJ/mol, which was determined in a previous study (see above, 2.), via detailed balance the following expression for the forward reaction (11) was obtained for a temperature range of 400 to 2200K:

k11 = 1.5E4·T2.6·exp(-25 kJ/mol/RT) cm3/mols

This expression is in very good agreement with the reported experimental values for k_11.

 

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