Forskning ved Københavns Universitet - Københavns Universitet

Forside

Atmospheric Chemistry of Trimethoxymethane, (CH3O)3CH; Laboratory Studies

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

A pulse radiolysis technique was used to measure the UV absorption spectra of (CH3O)2CHOCH2(.) and (CH3O)2CHOCH2O2(.) radicals derived from trimethoxymethane over the range 220-320 nm, σ250 nm (CH3O)2- CHOCH2(.) = (2.8 ± 0.4) × 10-18 and σ250nm (CH3O)2CHOCH2O2(.) = (3.5 ± 0.4) × 10-18 cm2 molecule-1. The self-reaction rate constants for (CH3O)2CHOCH2(.) and (CH3O)2CHOCH2O2(.) radicals, defined as -d[(CH3O)2CHOCH2(.)]/dt = 2k5[(CH3O)2CHOCH2(.)]2 and -d[(CH3O)2CHOCH2O2(.)]/dt = 2k6, obS[(CH3O)2-CHOCH2O 2(.)]2 were k5 = (3.5 ± 0.5) × 10-11 and k6 obs = (1.3 ± 0.2) × 10-11 cm3 molecule-1 s-1. Rate constants for reactions of (CH3O)2CHOCH2O2(.) radicals with NO and NO2 were k7 = (9.0 ± 1.2) × 10-12 and k8 = (1.0 ± 0.2) × 10-11 cm3 molecule-1 s-1, respectively. Rate constants for the reaction of OH radicals and F atoms with trimethoxymethane and the reaction of (CH3O)2CHOCH2(.) radicals with O2 were k1 = (6.0 ± 0.5) × 10-12, k3 = (3.0 ± 0.7) × 10-10, and k2 = (9.2 ± 1.5) × 10-12 cm3 molecule-1 s-1, respectively. Relative rate techniques were used to measure k(Cl + trimethoxymethane) = (1.5 ± 0.2) × 10-1 cm3 molecule-1 s-1. OH-radical-initiated oxidation of trimethoxymethane in air gives dimethyl carbonate in a molar yield of 81 ± 10%. These results are discussed with respect to the atmospheric chemistry of automotive fuel additives.

OriginalsprogEngelsk
TidsskriftJournal of Physical Chemistry A
Vol/bind103
Udgave nummer15
Sider (fra-til)2632-2640
Antal sider9
ISSN1089-5639
StatusUdgivet - 1 dec. 1999

ID: 223681309