Part 2: Hydrogen Bromide Both as Inhibitor and Catalyst of Self-Ignition

Inhibition of hydrogen oxidation by HBr and Br2

“…The inhibiting effect of bromine species has also been observed at lower temperatures in batch reactor [20,21] and flow reactor [22] experiments. However, static reactor experiments have shown that hydrogen bromide acts to catalyze the slow oxidation of hydrocarbons [5,[23][24][25][26][27][28][29].…”

Kinetics of Hydrogen Oxidation Part 3. Catalysis with Hydrogen Bromide

“…(-21) KLNETIC SCHEME OF INHLBITED OXIDATION Numerical analysis showed that direct inhibition by (21), (22), and (23)t could not account for the inhibiting effect. Previous experimental studies of the inhibition effectivity, carried out for many years, did not reveal this simple result, since no allowance was made for two essential phenomena: the regeneration of inhibitors in the course of oxidation (Lovachev et al, 1973), and catalysis by the same compounds that acted as inhibitors before (Lovachev et al, 1977). Catalysis appeared to be the result of two consecutive processes…”

“…The catalytic activity of H Br might considerably decrease the inhibition effectivity. Catalysis by bromine compounds at low temperatures has been studied in many experiments that are discussed by Cullis et al, (1963) and by Lovachev et al (1977). However, the effects now revealed by the solution of the kinetic equations have not been established before.…”

“…This seems to be due to the large amount of research required and the lack of sufficiently general concepts of flame structures and of the specific features of chain reactions. The paramount importance of free convection in inhibited homogeneous combustion has become evident now (Lovachev et 01.,.INTRODUCTION 191 Downloaded by [University of Cambridge] at 18:08 17 June 2016 Direct inhibition (Lovachev and Gontkovskaya, 1972;Lovachev et al, 1973Lovachev et al, , 1977 by the process (21) was found to be ineffective, as it was almost completely balanced by the reverse process catalysis. In view of the complicated dependences of the inhibition effectivity (Lovachev et al, 1977) it would seem to be expedient to begin with extensive numerical analysis of the isothermal kinetic equations.…”

“…Much effort will be required in order to thoroughly understand the mechanisms of flame inhibition and t See Tables I and 2. The hydrogen oxidation scheme (Lovachev et al, 1973(Lovachev et al, , 1977Kondratiev and Nikitin, 1974) is given in Table I, and that of inhibition in Table 2. The main elementary rate constants were taken from a Handbook (Kondratiev, 1970).…”