Mechanism of the photooxidation of gaseous formaldehyde

Su, Fu; Calvert, Jack G.; Shaw, John H.

doi:10.1021/j100488a001

Cited by 118 publications

(63 citation statements)

References 11 publications

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“…Table 111, although it was not detected in any significant amount at ppm concentrations. A similar dependence of the HC(0)OH yield on the concentration of aldehydic reactant has been observed previously in the HO, initiated oxidation of HCHO [11,19]. HC(0)OH is a wellknown product in the H0,-initiated oxidation of HCHO, i.e., reactions (14)- (16) [19-241. In the present study, since HCHO was formed in a significant amount, HC(0)OH observed is likely to be formed via these reaction steps.…”

Section: Resultssupporting

confidence: 72%

FTIR study of the Cl‐atom initiated oxidation of methylglyoxal

Green

Yarwood

Niki

1990

Int J of Chemical Kinetics

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The kinetics and mechanism of C1-atom initiated reactions of CH3C(0)CH0 were studied using the FTIR detection method in the photolysis (A > 300 nm) of C1,-CH3C(0)CH0 mixtures in 700 torr of Nz -O2 diluent at 298 2 2 K. The observed product distribution over the O2 pressure range from 0-700 torr, combined with relative rate measurements, provided evidence that: (1) the primary step is CI + CH,C(O)CHO --f HCl + CH3C(0)C0 with a rate constant of (4.8 ? 1.1) x lo-" cm3 molecule-' s-'; and (2) the predominant fate of the primary radical CH,C(O)CO under atmospheric conditions is unimolecular dissociation to CH3C(0) radicals and CO, rather than 0,-addition to yield the corresponding carbonylperoxy radical CH3C(0)C(O)O0.

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Section: Resultssupporting

confidence: 72%

FTIR study of the Cl‐atom initiated oxidation of methylglyoxal

Green

Yarwood

Niki

1990

Int J of Chemical Kinetics

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“…An example of the concentration profiles of HO-CH,OOH, HCOOH, HPMF, and FAN against the C,H, conversion [ 131 is reproduced in Figure 6 and in- Table I hydroperoxides have been isolated, probably due to high instability [ 5 ] . These results, namely the instability of the resulting hydroperoxides, are consistent with the results of the gas-phase ozonolysis [ 12,131, and also with the results of Su et al [25]. It was possible, however, to characterize and follow the formation and decay of HO-CH,-OOH in the gasphase C,H, ozonolysis [ 131.…”

Section: Formation Of Compound Z a N D Formic Acetic Anhydride With Tsupporting

confidence: 83%

Gas-phase ozonolysis of ethene in the presence of hydroxylic compounds

Neeb

Horie

Moortgat

1996

Int. J. Chem. Kinet.

125

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Ozonolysis of C2H4 was carried out at 295 K in 730 torr synthetic air in the concentration ranges of [O3]0 = 1.9–8.2 ppm and [C2H4]0 = 4.0–15.0 ppm, in the absence and presence of the added HCOOH (1 ppm), CH3COOH (1–10 ppm), and CH3OH (36–100 ppm). In the absence of the added compounds, a nearly complete analysis of the reaction products was achieved, with the yields expressed relative to the converted C2H4: HCHO 0.98, CO 0.26, CO2 0.18, HCOOH 0.05, and the sum of formic acid anhydride (FAN) and hydroperoxymethyl formate (HPMF), CHO(SINGLE BOND)O(SINGLE BOND)CH2OOH, 0.19. In the presence of the added HCOOH, the yield of [FAN + HPMF] increased. The addition of CH3COOH suppressed the formation of FAN and HPMF completely. The addition of large excesses of CH3OH also decreased the yield of [FAN + HPMF] significantly. In both cases, new products with the formula R(SINGLE BOND)O(SINGLE BOND)CH2OOH where R = CH3CO and CH3 for CH3COOH and CH3OH, respectively, were formed. The present results, together with the formation of hydroxymethyl hydroperoxide, HO(SINGLE BOND)CH2OOH, with added water vapor (Horie et al., Geophys. Res. Lett., 21, 1523, (1994)) were explained by the reaction of the Criegee biradical CH2OO with the added hydroxy compounds ROH. Formation of the products with the general formula R(SINGLE BOND)O(SINGLE BOND)CH2OOH indicates that the RO(SINGLE BOND)H bond fission has taken place. © 1996 John Wiley & Sons, Inc.

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“…This radical is so unstable that it immediately dissociates back to CH 2 O. However, a fraction reacts with HO 2 or itself producing HCOOH (Burrows et al, 1989;Su et al, 1979;Veyret et al, 1989) (see Sect. 3.2 for details).…”

Section: Methodsmentioning

confidence: 99%

Hydrogen isotope fractionation in the photolysis of formaldehyde

2008

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Abstract. Experiments investigating the isotopic fractionation in the formation of H 2 by the photolysis of CH 2 O under tropospheric conditions are reported and discussed. The deuterium (D) depletion in the H 2 produced is 500(±20)‰ with respect to the parent CH 2 O. We also observed that complete photolysis of CH 2 O under atmospheric conditions produces H 2 that has virtually the same isotope ratio as that of the parent CH 2 O. These findings imply that there must be a very strong concomitant isotopic enrichment in the radical channel (CH 2 O+hν→CHO+H) as compared to the molecular channel (CH 2 O+hν→H 2 +CO) of the photolysis of CH 2 O in order to balance the relatively small isotopic fractionation in the competing reaction of CH 2 O with OH. Using a 1-box photochemistry model we calculated the isotopic fractionation factor for the radical channel to be 0.22(±0.08), which is equivalent to a 780(±80)‰ enrichment in D of the remaining CH 2 O. When CH 2 O is in photochemical steady state, the isotope ratio of the H 2 produced is determined not only by the isotopic fractionation occurring during the photolytical production of H 2 (α m ) but also by overall fractionation for the removal processes of CH 2 O (α f ), and is represented by the ratio of α m /α f . Applying the isotopic fractionation factors relevant to CH 2 O photolysis obtained in the present study to the troposphere, the ratio of α m /α f varies from ∼0.8 to ∼1.2 depending on the fraction of CH 2 O that reacts with OH and that produces H 2 . This range of α m /α f can render the H 2 produced from the photochemical oxidation of CH 4 to be enriched in D (with respect to the original CH 4 ) by the factor of 1.2-1.3 as anticipated in the literature.

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Mechanism of the photooxidation of gaseous formaldehyde

Cited by 118 publications

References 11 publications

FTIR study of the Cl‐atom initiated oxidation of methylglyoxal

FTIR study of the Cl‐atom initiated oxidation of methylglyoxal

Gas-phase ozonolysis of ethene in the presence of hydroxylic compounds

Hydrogen isotope fractionation in the photolysis of formaldehyde

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