Vibrational spectroscopy of a cetane improver for biodiesel
Résumé
Biofuels represent one of the serious ways to succeed in the ecological transition. Diesel and biodiesel contains additives to facilitate the combustion reaction: theses additives improve the engine performance and reduce the emissions of unburned hydrocarbons, particulates, carbon monoxide and nitrogen oxides. These constituents are called cetane improvers and the most common is 2-ethyl hexylnitrate (2-EHN) [1].Since this additive is produced in very large quantities [2], it is important to be able to qualitatively and quantitatively identify its accidental release. The IR spectrum is needed for atmospheric detection.
We have accurately measured the room temperature absorption cross section of 2-EHN, between 850 and 3000 cm-1, using a FT-IR spectrometer. The main vibrational bands have been attributed, thanks to DFT calculations. Geometry optimizations also show the complexity of this flexible molecule, leading to almost iso-energetic conformers with slightly different vibrational spectra. The co-existence of all these isomers experimentally leads to particularly broad and complex absorption bands with shoulders. As an application, we also used these cross sections to probe the adsorption/desorption processes that can occur on the cell walls. All those aspects will be presented in this talk.
Origine | Fichiers produits par l'(les) auteur(s) |
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Origine | Fichiers produits par l'(les) auteur(s) |
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