Reaction of H with C 2 N 2 at pressures near 1 torr

The rate of disappearance of C 2 N 2 in the presence of a large excess of H atoms has been measured in a discharge‐flow system at pressures near 1 torr and temperatures in the range of 282–338 K. Under these conditions the reaction has a small negative temperature coefficient. A transition from second‐order to third‐order kinetics with decreasing pressure occurs at pressures near 1 torr. The results are discussed in terms of the mechanismwhere k 7 = (1.5 ± 0.2) × 10 –15 cm 3 /molec 1 ·sec is found for the forward rate of reaction (7). The results also give k 7 k 8 / k −7 = 3.7 × 10 −31 cm 6 /molec 2 ·sec and k 7 k 9 / k −7 = 3.0 × 10 −32 cm 6 /molec 2 ·sec, the first being probably an upper limit and the second probably a lower limit; hence k 8 / k 9 = 12 is found as an upper limit.