Kinetics and Mechanism of Hydroxyl Radical Reaction with Fluorinated Formates: A Theoretical Investigation.
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Accession number;02A0620435
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| Title;Kinetics and Mechanism of Hydroxyl Radical Reaction with Fluorinated Formates: A Theoretical Investigation. |
| Author;
CHANDRA A K
(Res. Inst. Innovative Technol. The Earth)
UCHIMARU T
(National Inst. Advanced Industrial Sci. And Technol., Tsukuba, Jpn)
URATA S
(Res. Inst. Innovative Technol. The Earth)
SUGIE M
(National Inst. Advanced Industrial Sci. And Technol., Tsukuba, Jpn)
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Journal Title;Fusso Kagaku Toronkai Koen Yoshishu
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Journal Code:F0135B
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ISSN:
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VOL.25th;NO.;PAGE.91-92(2001)
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| Figure&Table&Reference;FIG.1, TBL.1, REF.2 |
| Pub. Country;Japan |
| Language;English |
| Abstract;Hydrogen abstraction reactions between fluorinated methyl formates (CHnF3-nOCHO, n=0-2) and OH radicals have been investigated by using ab initio G2(MP2) theory. Fluorinated formates have two stable conformations depending upon the O-C-O-C torsional angle, namely syn(O-C-O-C=0.DEG.) and anti(O-C-O-C=180.DEG.). The free energy differences between the syn and anti conformers of CH2FOCHO, CHF2OCHO, and CF3OCHO amount to 2.8, 2.4, and 0.8kcal/mol, respectively. At room temperature more than 98% of CH2FOCHO and CHF2OCHO remain as syn conformer, while syn and anti population of CF3OCHO amount to 79% and 21%, respectively. The effect of fluorine substitution on the reactivity toward hydrogen abstraction has also been discussed. The rate constants of the reactions have been determined from the standard transition state theory taking into consideration the tunneling across the barrier. Arrhenius equations (within the temperature range of 250K to 450K) for hydrogen abstraction reactions of CH2FOCHO, CHF2OCHO, and CF3OCHO with OH radical are determined to be 7.8*10-13 exp(-760/T), 7.7*l0-13 exp(-896/T), and 5.4*l0-13 exp(-971/T)cm3 molecule-1sec-1, respectively. (author abst.) |
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