Kinetics of Pb reactions with N2O, Cl2, HCl, and O2 at high temperatures

The title reactions of ground-state lead atoms have been studied in isolation in an HTFFR thigh-temperature fast-flow reactor) at pressures in the 10-150 mbar range. Pb consumption rate coefficients were determined using atomic resonance absorption spectrometry at 217.0 and 283.3 nm. The following results, in cm(3) molecule(-1) s(-1), have been obtained: Pb + N2O, k(650-1205 K) = 1.8 x 10(-10) exp(-8948 K/T); Pb + Cl-2, k(530-1165 K) = 2.3 x 10(-10) exp(-718 WT); Pb + HCl, k(1090-1320 K) = 8.2 x 10(-10) exp(-17233 WT). The precision limits vary somewhat between these measurements; the estimated 2 sigma accuracy limits are all about +/-25%. The Pb + HCl result suggests that Do(Pb-Cl) = 318 +/- 31 kJ mol(-1). In contrast to the above homogeneous processes, the observations on the O-2 reaction indicate the dominance of heterogeneous reactions. It is speculated that these lead primarily to PbO2 below 1000 K and to PbO above 1000 K.