Atmospheric Oxidation of Furan and Methyl-Substituted Furans Initiated by Hydroxyl Radicals

作者：Yuan, Yi; Zhao, Xiaocan; Wang, Sainan; Wang, Liming^*

来源：Journal of Physical Chemistry A, 2017, 121(48): 9306-9319.

DOI：10.1021/acs.jpca.7b09741

• GAS-PHASE REACTIONS
• OH RADICALS
• TUNNELING CORRECTIONS
• RATE CONSTANTS
• MECHANISM
• KINETICS
• 3-METHYLFURAN
• PRODUCTS
• 2,5-DIMETHYLFURAN
• 2-METHYLFURAN

The atmospheric oxidation mechanism of furan and methylfurans (MFs) initiated by OH radicals is studied using high-level quantum chemistry and kinetic calculations. The reaction starts mainly with OH addition to the C2/C5-position, forming highly chemically activated adduct radical R2R5*, which would either be stabilized by collision or promptly isomerize to R2BR5B* by breaking the C2-O/C5-O bond and then isomerize to other conformers of R2B/R5B by internal rotations. Under the atmospheric conditions, the ring-retaining radical R2/R5 would recombine with 02 and be converted to a 5-hydroxy-2-furanone compound and a compound containing epoxide, ester, and carbonyl functional groups, while the ring-opening radicals R2B/R5B would react with 02 and form unsaturated 1,4-dicarbonyl compounds. RRKM-ME calculations on the fate of R2R5* from the addition of OH and furans predict that the fractions of R2B/R5B formation, i.e., the molar yields of the corresponding dicarbonyl compounds, are 0.73, 0.43, 0.26, 0.07, and 0.28 for furan, 2-MF, 3-MF, 2,3-DMF, and 2,5-DMF, respectively, at 298 K and 760 Torr when using the RHF-UCCSD(T)-F12a/cc-pVDZ-F12 reaction energies and barrier heights. The predicted yields for dicarbonyl compounds agree reasonably with recent experimental measurements. Calculations here also suggest high yields of ring-retaining 5-hydroxy-2-furanone compounds, which might deserve further study.

• 出版日期2017-12-7
• 单位华南理工大学