REACTION BETWEEN METHYLAMINE AND OXYGEN ON POLYCRYSTALLINE PLATINUM

Heterogeneous ignition and steady-state kinetics of reaction between m ethylamine and excess oxygen on polycrystalline platinum have been stu died in a mixed reactor. The oxidation of hydrogen initiates the ignit ion, and the released heat which increases the temperature of platinum wire accelerates the decomposition of methylamine, and then more hydr ogen is released until a final steady-state of the system is reached. CH3NH2 --> HCN + 2H(2), 2H(2) + O-2 --> 2H(2)O, and HCN + 7/4 O-2 --> NO + CO2 + 1/2 H2O, are the reactions which react when a mixture of me thylamine and oxygen contacts a high-temperature Pt wire. The flux lim ited kinetics of these three reactions can be described by Langmuir-Hi nshelwood (LH) rate expressions with empirical expressions for the sti cking coefficients. It is found that these Langmuir-Hinshelwood rate e xpressions correlate all rate data within +/-15% at all temperatures a nd pressures. The results suggest that the reactive species are strong ly inhibited by molecular oxygen. The selectivities of products can be quantitatively determined.