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Atmospheric chemistry of isopropyl formate and tert ‐butyl formate
Author(s) -
Pimentel Andre Silva,
Tyndall Geoffrey S.,
Orlando John J.,
Hurley Michale D.,
Wallington Timothy J.,
Sulbaek Andersen Mads P.,
Marshall Paul,
Dibble Theodore S.
Publication year - 2010
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20498
Subject(s) - chemistry , formate , ethyl formate , isopropyl , acetone , methyl formate , formic acid , formaldehyde , radical , isopropyl alcohol , medicinal chemistry , isomerization , methanol , photochemistry , organic chemistry , catalysis
Formates are produced in the atmosphere as a result of the oxidation of a number of species, notably dialkyl ethers and vinyl ethers. This work describes experiments to define the oxidation mechanisms of isopropyl formate, HC(O)OCH(CH 3 ) 2 , and tert ‐butyl formate, HC(O)OC(CH 3 ) 3 . Product distributions are reported from both Cl‐ and OH‐initiated oxidation, and reaction mechanisms are proposed to account for the observed products. The proposed mechanisms include examples of the α‐ester rearrangement reaction, novel isomerization pathways, and chemically activated intermediates. The atmospheric oxidation of isopropyl formate by OH radicals gives the following products (molar yields): acetic formic anhydride (43%), acetone (43%), and HCOOH (15–20%). The OH radical initiated oxidation of tert ‐butyl formate gives acetone, formaldehyde, and CO 2 as major products. IR absorption cross sections were derived for two acylperoxy nitrates derived from the title compounds. Rate coefficients are derived for the kinetics of the reactions of isopropyl formate with OH (2.4 ± 0.6) × 10 −12 , and with Cl (1.75 ± 0.35) × 10 −11 , and for tert ‐butyl formate with Cl (1.45 ± 0.30) × 10 −11 cm 3 molecule −1 s −1 . Simple group additivity rules fail to explain the observed distribution of sites of H‐atom abstraction for simple formates. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 479–498, 2010