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| Identifier |
uch.chemistry.msc//2005papanastasiou |
| Title |
Κινητική μελέτη της τροποσφαιρικής αποικοδόμησης της ακετόνης, στην αέρια φάση |
| Alternative Title |
Kinetic and mechanistic stydy of tropospheric oxidation of acetone in gas phase |
| Creator |
Papanastasiou, Dimitris
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| Abstract |
The topic of the present work was the kinetic and mechanistic investigation of the primary chemical degradation of acetone (CH3C(O)CH3), in the troposphere. In particular, the absolute rate coefficients for the reactions of OH radicals and Cl atoms with acetone were determined for 298 K and 273 363 K range of temperature, respectively. The incentive for the present study was the significant role that acetone plays, especially, in the region of upper troposphere, where it is considered as the major source of ΗΟx radicals (Hydro Peroxy Radicals) and PAN (Peroxy Acety Nitrate) species. The absolute rate measurements for the reactions of acetone with Cl atoms and OH radicals took place in two separate flow systems applying the effusive molecular beam technique of VLPR (Very Low Pressure Reactor). Especially, for the case of OH radicals, their detection and the subsequent quantitative analysis took place by using the LIF (Laser Induced Fluorescence) spectroscopy. On the other hand, acetone, Cl atoms and the stable products of both reactions were continuously monitored by using mass spectrometry. The absolute rate coefficients that were derived for the reactions of acetone with OH radicals ( 298 1 k ) and Cl atoms ( 298 2 k , k2(T)) are given by the following expressions: 298 1 k = (2.14 ± 0.39) × 10-13 cm3 molecules-1 s-1 298 2 k = (3.04 ± 0.33) × 10-12 cm3 molecules-1 s-1 k2(T) = (4.30 ± 0.57)×10-11 exp ( T 808 ± 82 ) As far as the mechanistic investigation of acetones reactions with OH radicals and Cl atoms is concerned, the experimental results showed that both reactions mainly proceed via hydrogen metathesis mechanism, resulting in the stable products of H2O and HCl, respectively, and the corresponding dehydrogenated acetonyl radical.
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| Subject |
χημική κινητική, ακετόνη, ρίζες υδροξυλίου, ατομικό χλώριο, ανώτερη τροπόσφαιρα,chemical kinetics, acetone, hydroxyl radical, OH, chlorine atoms, Cl, upper |
| Issue date |
2005-07-01 |
| Date available |
2007-01-24 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
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Type of Work--Post-graduate theses
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| Views |
185 |
Κινητική μελέτη της τροποσφαιρικής αποικοδόμησης της ακετόνης, στην αέρια φάση
