Rate constants for the reactions of OH radicals and Cl atoms with Di‐n‐Propyl ether and Di‐n‐Butyl ether and their deuterated analogs

Abstract

Using relative rate methods, rate constants for the gas-phase reactions of OH radicals and Cl atoms with di-n-propyl ether, di-n-propyl ether-d 14 , di-n-butyl ether and di-nbutyl ether-d 18 have been measured at 296 Ϯ 2 K and atmospheric pressure of air. The rate constants obtained (in cm 3 molecule Ϫ1 s Ϫ1 units) were: OH radical reactions, di-n-propyl ether, (2.18 Ϯ 0.17) ϫ 10 Ϫ11

Atmospheric Degradation of Volatile Organic Compounds

“…Clearly, curved Arrhenius plots are observed (as is also the case for alkanes; see Figure 1) and at elevated temperatures the rate constants are observed to increase, or are expected to increase, with increasing temperature (for example, although not shown in Figure 5, at temperatures above 600 K the rate constant for reaction of OH radicals with acetaldehyde increases rapidly with increasing temperature 206 ). Measurements of the OH radical reaction rate constants for deuterated 2-propanol, 202 acetaldehyde, 206 and diethyl ether 207 (and other ethers 208 ) show that for these compounds, despite their negative temperature dependencies in certain temperature regimes, the rate-determining step in the OH radical reaction involves H-atom abstraction, probably through hydrogen-bonded intermediates. 209 Although there are numerous atmospherically relevant classes of oxygenated VOCs, many of which are formed in situ in the troposphere from other VOCs, we deal here only with aliphatic and aromatic aldehydes, RCHO, aliphatic ketones, RC(O)R′, aliphatic alcohols, ROH, and aliphatic ethers, ROR′; where R and R′ are alkyl or (for the aromatic aldehydes) aryl groups.…”

“…Rate constants have been measured at temperatures down to ∼230 K for several of these ethers, including those listed in Table 1. These reactions proceed by H-atom abstraction, 29,30,207,208 with the C-H bonds on the carbon atom adjacent to the ether O-atom being markedly activated 200 (and with activation of C-H OH + CH 3 CH(OH)CH 2 CH 3 f H 2 O + CH 3 C • (OH)CH 2 CH 3 (13) CH 3 C • (OH)CH 2 CH 3 + O 2 f CH 3 C(O)CH 2 CH 3 + HO 2 (14) bonds occurring for H atoms located on carbon atoms several away from the ether O-atom). The intermediate alkoxy radicals ROC(O • )R′R′′ (R and R′ ) alkyl and R′′ ) H or alkyl) typically decompose to form an ester.…”

Atmospheric degradation of 2-chloroethyl vinyl ether, allyl ether and allyl ethyl ether: Kinetics with OH radicals and UV photochemistry

“…When the reactivity of 2-chloroethyl ethyl ether is compared with that of 2ClEVE, a decrease of 5 times in k OH is observed (Dalmasso et al, 2010). The same trend is observed when comparing the OH-reactivity of AE and ethyl ether (Lloyd et al, 1976;Wallington et al, 1988Wallington et al, , 1989Bennett and Kerr, 1989;Bennett and Kerr, 1990;Nelson et al, 1990;Mellouki et al, 1995;Harry et al, 1999). The OH-reaction mechanism of saturated ethers is dominated by hydrogen abstraction, so the increase of reactivity when a double bond is introduced in the molecule may indicate that there is a contribution of the addition pathway.…”