Ozonolysis of prenol, a second-generation biofuel, in atmospheric simulation chambers: Temperature dependent kinetics and gas-phase products analysis

Abstract

Prenol (3-methyl-2-buten-1-ol), a second-generation biofuel, is released in the atmosphere during its use and storage where it can react with atmospheric oxidants. In this study, the ozonolysis reaction of prenol was investigated in two atmospheric simulation chambers CHARME (CHamber for the Atmospheric Reactivity and Metrology of the Environment) and THALAMOS (Thermally Regulated Atmospheric Simulation Chamber). PTR-ToF-MS and SIFT-MS were used to monitor the concentrations of organic compounds versus time. The room temperature (293 ± 2 K) rate coefficient was determined using the relative and pseudo-first order methods. The values obtained using both methods in the two chambers were in accordance, leading to an average rate coefficient of (3.26 ± 0.33) × 10⁻¹⁶ cm³ molecule⁻¹ s⁻¹. The temperature-dependent rate coefficient of this reaction was also investigated using the relative method in the temperature range 283–353 K. The following Arrhenius expression: $k=\left(9.83\pm 1.7\right)\times {10}^{-16}\times \exp \left(\frac{-331\pm 53}{T}\right)$ cm³ molecule⁻¹ s⁻¹ was obtained. The gas-phase oxidation products formed, at room temperature (293 ± 2 K), from this reaction were investigated using PTR-ToF-MS, SIFT-MS and GC-EI-MS analyses. Several products were identified and quantified (in %), including acetone (9 ± 2), whose formation yield was determined using a calibration standard, and acetaldehyde (30 ± 5), glycolaldehyde (30 ± 5), formaldehyde (8 ± 1), methylglyoxal (8 ± 1) and hydroxyacetone and/or methylacetate (5 ± 1) %, whose formation yields were estimated using a generic H₃O⁺ rate coefficient for their protonation reaction. Glyoxal was also observed but not quantified. The kinetic data are compared with literature and a reaction mechanism is proposed. To our knowledge, this work is the first one presenting the mechanistic study and Arrhenius equation for the ozonolysis reaction of prenol.