Gas phase chain reaction of H2O2+ NO2+ CO

Abstract

Reactions in gas phase mixtures of H z 0 2 vapour, NO2 and CO at 292k 2 K have been studied by measurement of the variation of yield of the COz product. It has been shown that the mechanism is the chain reaction sequenceprovided that excess NOz is present. second and third order for M = CO at pressures of 8 and 13.3 kN m-2.An estimate of k4/k2 is obtained which is rationalised in terms of reaction (4) being between Addition of n-butane to the mixture induces the reactionOH+n-C4HIo-+H20+n-C4H9. ( 8)From the resultant decrease in the kinetic chain length a ratio of ks/kz = 14.8 If: 0.9 is deduced, in good agreement with ratios of available absolute values of ks and k 2 .It is considered that the H202 +NO2 + CO + substrate reaction system provides a useful nonphotolytic source of OH-tsubstrate rate constant data relative to k2, of wider application than photolytic sources so far developed.

A new method for the synthesis of nitroethane, ethyl nitrite, and ethyl nitrate

“…At ambient temperature and a total pressure of ca. 40 kPa, this procedure yielded a value for the ratio [OH-],: [H,O,], corresponding to 0.45 A-0.03 :1, which is consistent with the total yields shown in Table 1, taking account of the relatively small effect of reaction (5). Such an efficiency of reaction (1) on a boric acid-coated surface lies within the range encountered before.6,s Since boric acid surfaces with efficiencies close to 100% have been obtained,6 it is not unreasonable to expect that the yields shown in Table 1 ( 5 ) We interpret our results on the basis of the mechanism given by equations ( 6)-(10).…”

“…A slight decrease in the total yield of these products with increasing [NO,]: [C,H,] ratio is expected since there is competition for OH. between step (2) and step (5). The sum of the yields in Table 1 OH* + NO,(+M) + HNO,(+M) is significantly less (43 i 4%) than [H,O,],.…”

Determination of Atmospheric Lifetimes via the Measurement of OH Radical Kinetics

“…Finally, several relative rate studies have been performed by using nonphotolytic “dark” chemical sources of hydroxyl radicals. Heterogeneous OH formation in a H 2 O 2 /NO 2 -containing mixture was used by Campbell et al, whereas Barnes et al used the homogeneous thermal decomposition of HO 2 NO 2 in the presence of NO The gas reaction between O 3 and N 2 H 4 was used by Tuazon et al to maintain a OH concentration of about 3 × 10 7 molecule/cm 3 .…”