Flame inhibition by methyl bromide

✍ Scribed by C.P. Fenimore; G.W. Jones

• Publisher: Elsevier Science
• Year: 1963
• Tongue: English
• Weight: 624 KB
• Volume: 7
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(63)90207-4

✦ Synopsis

Burdon et al. proposed that at the flammability limit of methyl bromide-hydrogen-air mixtures, the generation of free radicals bv (1).

H+&+OH+O, was cancelled bv an eaual occurrence of (2),-H+CH3B&Ha+HBr; aid'& @@o&mate value of kz can be deduied on this interpretation. By probing flames burning on a cooled porous plate at low pressure, an independent estimate of kz has been obtained, k7=1*4X lOl3 cm3 mole-l set-1 at 1900°K. which a.erees within a fhctor of two with the ks from flammability limits. It is concluded that the interpretation of the latter was approximately valid, though doubtless not exact. Methyl bromide is not an effective inhibitor in nitrous oxide flames where [H] is only about the equilibrium concentration; but is in oxygen flames where radical concentrations are greater than eauilibrium. The excess THl is reduced in the Presence of the inhibitor and a higher reaction temperature is necessary io'maintain the same burning 'velocity. The methyl radical must be responsible for a large part of the effect, but hydrogen bromide also plays a role. In the course of the work, CHs+NO + CHaNO. the rate constant was estimated for the reaction The value is consistent with lower temperature results but does not prove whether the reaction is really bimolecular or termolecular in flames.