Tetsu Takeyama

Kinetics of Hydrogen—Oxygen Reaction in Shock Waves

The hydrogen—oxygen reaction in reflected shock waves has been studied in the range of conditions 890°≤T≤1350°K, 4.5≤P≤5.6 atm, 1.3≤O2≤13×10—3 moles/liter, and 0.5≤[H2]/[O2]≤2. Measurements of both the induction period of OH absorption and that of pressure increase suggest that the reaction H+O2→OH+O is the rate‐determining step of OH formation in this temperature range and has an activation energy of 18.9±0.9 kcal/mole, but that the rate‐determining step of over‐all reaction is HO2+H2→H2O2+H below 1100°K, while H+O2→OH+O is rate determining above 1100°K. Also, the mechanism of the hydrogen—oxygen reaction below 1100°K is discussed in some detail.

A shock-tube study of the ammonia-oxygen reaction

An investigation was made of the three different stages of the ammonia-oxygen reaction over the temperature range of 1500°–2800°K: (1) The measurements of induction periods for the appearance of OH absorption at 3067and the time relations among concentrations of OH, NH, NO, and NH2, which were identified spectrophotometrically, led to a reaction mechanism for the induction period in which the reaction NH2+O2→NH+HO2 is rate controlling. (2) The rate of ammonia consumption immediately after the induction period has been measured by monitoring the absorption by ammonia at 2245and found to be expressed by −(d[NH3]/dt)0=k0[NH3]1.5[O2]0.5[Ar]0.5 with k0(l1.5 mole−1.5 sec−1)=1012.77 exp (−38,800/RT). (3) A weak emission of OH was found to follow a spike, which is observed at the end of the induction period, and persist at constant level up to 500 μsec. This weak emission was demonstrated to be chemiluminescence, the mechanism of which was discussed in connection with that claimed for the hydrogen-oxygen reaction.