Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical Study
Under tropospheric conditions, 2-butenedial is photochemically removed to produce secondary organic aerosol. Upon solar irradiation in the lower troposphere, the main photochemical products are ketene-enol (a key intermediate product), furanones, and maleic anhydride. The oxidative reaction mechanis...
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| Format: | Article |
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MDPI AG
2023-06-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/13/4994 |
| _version_ | 1797591222332686336 |
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| author | Andrea Maranzana Glauco Tonachini |
| author_facet | Andrea Maranzana Glauco Tonachini |
| author_sort | Andrea Maranzana |
| collection | DOAJ |
| description | Under tropospheric conditions, 2-butenedial is photochemically removed to produce secondary organic aerosol. Upon solar irradiation in the lower troposphere, the main photochemical products are ketene-enol (a key intermediate product), furanones, and maleic anhydride. The oxidative reaction mechanism was studied using the multireference method CASSCF to explore the hypersurface of the two most accessible singlet excited states, and by DFT for the ground state. Photoisomerization of 2-butenedial in the first excited state directly produces ground state ketene-enol upon nonradiative relaxation. From this intermediate, furan-2-ol and successively 3H-furan-2-one and 5H-furan-2-one are formed. The cooperative effect of two water molecules is essential to catalyze the cyclization of ketene-enol to furan-2-ol, followed by hydrogen transfers to furanones. Two water molecules are also necessary to form maleic anhydride from furan-2-ol. For this last reaction, in which one extra oxygen must be acquired, we hypothesize a mechanism with singlet oxygen as the oxidant. |
| first_indexed | 2024-03-11T01:34:24Z |
| format | Article |
| id | doaj.art-9ba33ec2d1024bd0b618bc74a6d7b0e5 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-11T01:34:24Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-9ba33ec2d1024bd0b618bc74a6d7b0e52023-11-18T17:06:38ZengMDPI AGMolecules1420-30492023-06-012813499410.3390/molecules28134994Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical StudyAndrea Maranzana0Glauco Tonachini1Dipartimento di Chimica, Università di Torino, Corso Massimo D’Azeglio 48, I-10125 Torino, ItalyDipartimento di Chimica, Università di Torino, Corso Massimo D’Azeglio 48, I-10125 Torino, ItalyUnder tropospheric conditions, 2-butenedial is photochemically removed to produce secondary organic aerosol. Upon solar irradiation in the lower troposphere, the main photochemical products are ketene-enol (a key intermediate product), furanones, and maleic anhydride. The oxidative reaction mechanism was studied using the multireference method CASSCF to explore the hypersurface of the two most accessible singlet excited states, and by DFT for the ground state. Photoisomerization of 2-butenedial in the first excited state directly produces ground state ketene-enol upon nonradiative relaxation. From this intermediate, furan-2-ol and successively 3H-furan-2-one and 5H-furan-2-one are formed. The cooperative effect of two water molecules is essential to catalyze the cyclization of ketene-enol to furan-2-ol, followed by hydrogen transfers to furanones. Two water molecules are also necessary to form maleic anhydride from furan-2-ol. For this last reaction, in which one extra oxygen must be acquired, we hypothesize a mechanism with singlet oxygen as the oxidant.https://www.mdpi.com/1420-3049/28/13/4994CASSCFCCSD(T)DFT2-butenedialtropospheric oxidationreaction mechanism |
| spellingShingle | Andrea Maranzana Glauco Tonachini Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical Study Molecules CASSCF CCSD(T) DFT 2-butenedial tropospheric oxidation reaction mechanism |
| title | Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical Study |
| title_full | Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical Study |
| title_fullStr | Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical Study |
| title_full_unstemmed | Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical Study |
| title_short | Mechanism of the Photochemical Isomerization and Oxidation of 2-Butenedial: A Theoretical Study |
| title_sort | mechanism of the photochemical isomerization and oxidation of 2 butenedial a theoretical study |
| topic | CASSCF CCSD(T) DFT 2-butenedial tropospheric oxidation reaction mechanism |
| url | https://www.mdpi.com/1420-3049/28/13/4994 |
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