Rate coefficients for the gas‐phase OH + furan (C₄H₄O) reaction between 273 and 353 K

Abstract

Rate coefficients, k1, for the gas‐phase OH radical reaction with the heterocyclic ether C4H4O (1,4‐epoxybuta‐1,3‐diene, furan) were measured over the temperature range 273–353 K at 760 Torr (syn. air). Experiments were performed using: (i) the photochemical smog chamber THALAMOS (thermally regulated atmospheric simulation chamber, IMT NE, Douai‐France) equipped with Fourier Transform Infrared (FTIR) and Selected Ion Flow Tube Mass Spectrometry (SIFT‐MS) detection methods and (ii) a photochemical reactor coupled with FTIR spectroscopy (PCR, University of Crete, Greece). k1(273–353 K) was measured using a relative rate (RR) method, in which the loss of furan was measured relative to the loss of reference compounds with well‐established OH reaction rate coefficients. k1(273–353 K) was found to be well represented by the Arrhenius expression (1.30 ± 0.12) × 10−11 exp[(336 ± 20)/T] cm3 molecule−1 s−1, with k1(296 K) measured to be (4.07 ± 0.32) × 10−11 cm3 molecule−1 s−1. The k1(296 K) and pre‐exponential quoted error limits are 2σ and include estimated systematic errors in the reference rate coefficients. The observed negative temperature dependence is consistent with a reaction mechanism involving the OH radical association to a furan double bond. Quantum mechanical molecular calculations show that OH addition to the α‐carbon (ΔHr(296 K) = −121.5 kJ mol−1) is thermochemically favored over the β‐carbon (ΔHr(296 K) = −52.9 kJ mol−1) addition. The OH‐furan adduct was found to be stable over the temperature range of the present measurements. Maleic anhydride (C4H2O3) was identified as a minor reaction product, 3% lower‐limit yield, demonstrating a non‐ring‐opening active reaction channel. The present results are critically compared with results from previous studies of the OH + furan reaction rate coefficient. The infrared spectrum of furan was measured as part of this study and its estimated climate metrics are reported.

Emissions and Atmospheric Chemistry of Furanoids from Biomass Burning: Insights from Laboratory to Atmospheric Observations

“…(see Table 3). to those of Angelaki et al 122 The solid line is a fit of the measurements to a modified Arrhenius expression were used by Illeś et al 115 The results from these studies agree to within 22%. Ravishankara et al, 111 Wallington et al, 112 and Moriarty et al 113 applied absolute methods to determine the roomtemperature (296−300 K) rate coefficient of the THF + OH reaction under pseudo-first-order conditions in excess of THF.…”

“…The temperature dependence of the OH + furan rate coefficient has been reported by Wine and Thompson (254–425 K), Whelan et al (294–595 K), Angelaki et al (273–353 K), and Elwardany et al (924–1388 K). Angelaki et al applied the relative rate method to determine temperature-dependent rate coefficients. Furan and tetrahydrofuran were used as reference molecules.…”

“…The literature results are presented in Table 3 and displayed in Figure 7. Atkinson et al, 117 Bierbach et al, 119 and Angelaki et al 122 used relative rate methods to measure a room-temperature rate coefficient (296−302 K). Atkinson et al 117 and Bierbach et al 119 monitored the mixture by GC-FID and used n-hexane and propene as reference molecules, respectively.…”

“…133 The reference rate constant used by Bierbach et al 119 is consistent with the latest NASA JPL evaluation 134 and was not revised. Angelaki et al 122 performed kinetic measurements using atmospheric chambers with SIFT-MS and FTIR as detection techniques. Isoprene, n-butanol, THF, and trifluoroethylene (HFO-1123) were the reference molecules used.…”

“…Summary of literature data for the reaction of furan with OH, − after scaling the values of Whelan et al and Wine and Thompson, to those of Angelaki et al The solid line is a fit of the measurements to a modified Arrhenius expression k = A true( T 300 true) b + C true( T 1000 true) d nobreak0em0.25em⁡ exp ( − E R T ) (see Table ). …”