María Antiñolo

University of Castilla-La Mancha · Departamento de Química-Física

Formamide (NH2C(O)H) has been observed both in the interstellar medium (ISM), being identified as a potential precursor of prebiotic molecules in space, and in the Earth’s atmosphere. In these environments where temperature is very distinct, hydroxyl (OH) radicals may play an important role in the degradation of NH2C(O)H. Thus, in this work, we rep...

The kinetic study of the gas-phase reactions of hydroxyl (OH) radicals and chlorine (Cl) atoms with CF3CHFCF2OCH3 (HFE-356mec3) and CHF2CHFOCF3 (HFE-236ea1) was performed by the pulsed laser photolysis/laser-induced fluorescence technique and a relative method by using Fourier Transform infrared (FTIR) spectroscopy as detection technique. The tempe...

The kinetic study of the gas-phase reactions of hydroxyl (OH) radicals and chlorine (Cl) atoms with CF 3 CHFCF 2 OCH 3 (HFE-356mec3) and CHF 2 CHFOCF 3 (HFE-236ea1) was performed by the pulsed laser photolysis/laser-induced fluorescence technique and a relative method by using Fourier Transform infrared (FTIR) spectroscopy as detection technique. T...

The tropospheric fate of 2-methylpentanal (2MP) has been investigated in this work. First, the photochemistry of 2MP under simulated solar conditions was investigated by determining the UV absorption cross sections (220–360 nm) and the effective photolysis quantum yield in the UV solar actinic region (λ > 290 nm). The photolysis rate coefficient in...

The tropospheric fate of 2-methylpentanal (2MP) has been investigated in this work. First, the photochemistry of 2MP under simulated solar conditions was investigated by determining the UV absorption cross sections (220–360 nm) and the effective photolysis quantum yield in the UV solar actinic region (λ > 290 nm). The photolysis rate coefficient in...

Peroxides (H2O2, ROOR, ROOH) play an important atmospheric role in both the gas and particle phases. Several techniques are available in the literature for their quantification, although current techniques are very expensive or time-consuming. In the present work, a new fast and sensitive iodometric-spectrophotometric method, based on the tradition...

The gas-phase reaction between trans-2-hexenal (T2H) and chlorine atoms (Cl) was studied using three complementary experimental setups at atmospheric pressure and room temperature. In this work, we studied the rate constant for the titled oxidation reaction as well as the formation of the gas-phase products and secondary organic aerosols (SOAs). Th...

Hydrofluoroethers (HFEs), such as CF3CH2OCH3 (HFE-263fb2), CHF2CF2CH2OCH3 (HFE-374pcf), and CF3CF2CH2OCH3 (HFE-365mcf3), have been proposed in the last few decades as the third-generation replacements for perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) because of their zero stratospheric ozone depletion potentials and relatively low global wa...

Saturated aldehydes, e.g. 2-methylbutanal (2 MB, CH3CH2CH(CH3)C(O)H), are emitted into the atmosphere by several biogenic sources. The first step in the daytime atmospheric degradation of 2 MB involves gas-phase reactions initiated by hydroxyl (OH) radicals, chlorine (Cl) atoms, and/or sunlight. In this work, we report the rate coefficients for the...

Saturated aldehydes, e.g. 2-methylbutanal (2MB, CH3CH2CH(CH3)C(O)H), are emitted into the atmosphere by several biogenic sources. The first step in the daytime atmospheric degradation of 2MB involves gas-phase reactions initiated by hydroxyl (OH) radicals, chlorine (Cl) atoms and/or sunlight. In this work, we report the rate coefficients for the ga...

The role of water vapor (H2O) and its hydrogen-bonded complexes in the gas-phase reactivity of organic compounds with hydroxyl (OH) radicals has been the subject of many recent studies. Contradictory effects have been reported at temperatures between 200 and 400 K. For the OH + acetaldehyde reaction, a slight catalytic effect of H2O was previously...

The gas-phase reaction of trans-2-pentenal (T2P) with Cl atoms was studied at atmospheric pressure and room temperature. A rate coefficient of (2.56±0.83)×10-10 cm3 molecule-1 s-1 was obtained using the relative rate method and isoprene, cyclohexane and ethanol as reference compounds. The kinetic study was carried out using a 300-L Teflon bag simul...

The gas-phase reaction between trans-2-methyl-2-butenal and chlorine (Cl) atoms has been studied in a simulation chamber at 298 ± 2 K and 760 ± 5 Torr of air under free-NOx conditions. The rate coefficient of this reaction was determined as k = (2.45 ± 0.32) × 10−10 cm3 molecule−1 s−1 by using a relative method and Fourier transform infrared spectr...

Allyl cyanide, CH2CHCH2CN, is a volatile organic compound that is emitted by biogenic and anthropogenic sources. Daytime atmospheric degradation of CH2CHCH2CN may be initiated by reaction with OH radicals, Cl atoms and O3. In this work, we report the gas-phase rate coefficients for the reaction of these atmospheric oxidants with CH2CHCH2CN (k1, k2...

The rate coefficient, k(T), for the gas-phase reaction between OH radicals and acetone CH3C(O)CH3, has been measured using the pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique (T = 11.7-64.4 K). The temperature dependence of k(T = 10-300 K) has also been computed using a RRKM-Master equation analysis after...

The rate coefficients, k ( T = 11.7 – 64.4 K), for the gas-phase reaction between OH radicals and acetone, CH 3 C(O) CH 3 , have been measured using the pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique, the most suitable one to cool down gases below the freezing point without gas condensation. The experimen...

Methanol (CH 3 OH) and hydroxyl (OH) radicals are two species abundant in cold and dense molecular clouds which are important for the chemistry of the interstellar medium (ISM). CH 3 OH is a well-known starting point for the formation of more complex organic molecules (COMs) in these molecular clouds. Thus, the reactivity of CH 3 OH in the gas-phas...

The reactivity of methanol (CH3OH) toward the hydroxyl (OH) radical was investigated in the temperature range 11.7 – 177.5 K using the CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique. In the present study, the temperature dependence of the rate coefficient for the OH+CH3OH reaction, k(T), has been revisited and a...

Cigarette smoke is an important source of particles and gases in the indoor environment. In this work, aging of side-stream cigarette smoke was studied in an environmental chamber via exposure to ozone (O3), hydroxyl radicals (OH) and indoor fluorescent lights. Aerosol mass concentrations increased by 13-18% upon exposure to 15 ppb O3 and by 8-42%...

The relative-rate technique has been used to determine the rate coefficient for the reaction of CxF2x+1CHCH2(x = 1, 2, 3, 4 and 6) with ozone at (298 ± 2) K and (720 ± 5) Torr of air by FTIR (Fourier Transform Infrared Spectroscopy) and by GC-MS/SPME (Gas Chromatography-Mass Spectroscopy with Solid Phase Micro Extraction) in two different atmospher...

The article “Methanol dimer formation drastically enhances hydrogen abstraction from methanol by OH at low temperature” proposes a dimer mediated mechanism in order to explain the large low temperature rate coefficients for the OH + methanol reaction measured by several groups. It is demonstrated here theoretically that under the conditions of thes...

Ethanol, CH3CH2OH, has been unveiled in the interstellar medium (ISM) by radioastronomy and it is thought to be released into the gas phase after the warm-up phase of the grain surface, where it is formed. Once in the gas phase, it can be destroyed by different reactions with atomic and radical species, such as hydroxyl (OH) radicals. The knowledge...

The chemical kinetics of neutral–neutral gas-phase reactions at ultralow temperatures is a fascinating research subject with important implications on the chemistry of complex organic molecules in the interstellar medium (T ~ 10–100 K). Scarce kinetic information is currently available for these kinds of reactions at T < 200 K. In this work, we use...

We report here the rate coefficients for the OH-reactions (kOH) with E-CF3CH=CHF and Z-CF3CH=CHF, potential substitutes of HFC-134a, as a function of temperature (263-358 K) and pressure (45-300 Torr) by pulsed laser photolysis coupled to laser induced fluorescence techniques. For the E-isomer, the existing discrepancy among previous results on the...

In many industrial applications, (CF3)2CFCN has been suggested as SF6 substitute, which possess a global warming potential (GWP100-yr) of 23500 relative to CO2. The temperature dependence of the rate coefficient (kOH) for the OH + (CF3)2CFCN reaction is reported for the first time: kOH(278–358 K) = (5.9 ± 3.2) × 10⁻¹³exp{−(1856 ± 162)/T} cm³ molecu...

Rate coefficients for the gas-phase reactions of CxF2x+1CHCH2 (x = 1, 2, 3, 4 and 6) with Cl atoms were determined at (298 ± 2) K and (710 ± 5) Torr of air using a relative rate technique. Two experimental setups with simulation chambers were employed with Fourier Transform Infrared (FTIR) spectroscopy and Gas Chromatography coupled to Mass Spectro...

A series of three de Laval nozzles initially designed to generate uniform supersonic flows in helium at 23 and 36 K and in argon at 50 K have been used with either pure nitrogen or mixtures of nitrogen with helium or argon in order to make a sequence of pulsed supersonic flows working at different temperatures. For this, a computer homemade program...

In the last years, ultra-low temperature chemical kinetic experiments have demonstrated that some gas-phase reactions are much faster than previously thought. One example is the reaction between OH and CH3OH, which has been recently found to be accelerated at low temperatures yielding CH3O as main product. This finding opened the question of whethe...

In the last years, ultra-low temperature chemical kinetic experiments have demonstrated that some gas-phase reactions are much faster than previously thought. One example is the reaction between OH and CH3OH, which has been recently found to be accelerated at low temperatures yielding CH3O as main product. This finding opened the question of whethe...

The gas phase chemistry of neutral-neutral reactions of interest in the interstellar medium (ISM) is poorly understood. The rate coefficients (kOH) for the majority of the reactions of hydroxyl (OH) radicals with interstellar oxygenated species are unknown at the temperatures of the ISM. In this study, we present the first determination of kOH for...

This paper demonstrates that OH radicals are formed by photolysis of secondary organic aerosol (SOA) material formed by terpene ozonolysis. The SOA is collected on filters, dissolved in water containing a radical trap (benzoic acid), and then exposed to ultraviolet light in a photochemical reactor. The OH formation rates, which are similar for both...

Although it is known that soot particles are emitted in large quantities to the atmosphere, our understanding of their environmental effects is limited by our knowledge of how their composition is subsequently altered through atmospheric processing. Here we present an on-line mass spectrometric study of the changing chemical composition of hydrocar...

This paper demonstrates that OH radicals are formed by photolysis of secondary organic aerosol (SOA) material formed by terpene ozonolysis. The SOA aerosol is collected on filters, dissolved in water containing a radical trap (benzoic acid), and then exposed to ultraviolet light in a photochemical reactor. The OH formation rates, which are similar...

The toxicity of carbon nanotubes (CNTs) has received significant attention due to their usage in a wide range of commercial applications. While numerous studies exist on their impacts in water and soil ecosystems, there is a lack of information on the exposure to CNTs from the atmosphere. The transformation of CNTs in the atmosphere, resulting in t...

The relative importance in the atmosphere of UV photolysis of perfluoropropionaldehyde, CF3CF2CHO, and reaction with hydroxyl (OH) radicals has been investigated in this work. Firstly, the forbidden n-π* transition of the carbonyl chromophore was characterized between 230 and 380 nm as a function of temperature (269 - 298 K) and UV absorption cross...

Three different detection techniques, coupled to pulsed laser photolysis (PLP), have been employed to determine the quantum yields of CF3CH2CHO at 248 and 266 nm: CF3CH2CHO + h nu -> CF3CH2 + HCO (R1a), CF3CH2CHO + h nu -> CF3CH3 + CO (R1b), and CF3CH2CHO + h nu -> CF3CH2O + H (R1c). (a) In the presence of air, Fourier transform infrared (FTIR) spe...

An absolute kinetic study of the reaction of Cl atoms with CF3CF2CH2OH is reported as a function of temperature (T = 268–377 K) and at a total pressure of 100 Torr by the Pulsed Laser Photolysis - Resonance Fluorescence (PLP-RF) technique. No pressure dependence of the rate coefficient for the title reaction, k, was observed between 50 and 200 Torr...

This work constitutes the first study on the photochemical degradation process of CF3(CH2)2CHO. Firstly, the wavelength and temperature dependence of the UV absorption cross sections, σλ, was determined. The n → π* electronic transition band of CO chromophore was characterized between 230 and 340 nm in the 269–323 K range. A hyperchromic effect was...

Fluorinated alcohols, such as 2,2,3,3-tetrafluoropropanol (TFPO, CHF(2)CF(2)CH(2)OH) and 2,2,3,3,3-pentafluoropropanol (PFPO, CF(3)CF(2)CH(2)OH), can be potential replacements of hydrofluorocarbons with large global warming potentials, GWPs. IR absorption cross sections for TFPO and PFPO were determined between 4000 and 500 cm(-1) at 298 K. Integra...

Ultraviolet (UV) absorption cross sections of CF(3)CH(2)CHO were determined between 230 and 350 nm by gas-phase UV spectroscopy. The forbidden n → π* transition was characterized as a function of temperature (269-323 K). In addition, the photochemical degradation of CF(3)CH(2)CHO was investigated at 308 nm. The possible photolysis channels are: CF(...

In the solar system, the temperature (T) of the atmosphere of giant planets or their satellites is only several tens of Kelvin (K). The temperature of the tropopause of Titan (satellite of Saturn) and the surface of Mars is 70 K and 210 K, respectively. In the Earth's atmosphere, T decreases from 298 K (surface) to 210 K close to the T-inversion re...

The gas-phase kinetic coefficients of OH radicals with two primary fluorinated alcohols, CF(3)CH(2)CH(2)OH (k(1)) and CF(3)(CH(2))(2)CH(2)OH (k(2)), potential replacements of hydrofluorocarbons (HFCs), are reported here as a function of temperature (T = 263-358 K) for the first time. k(1) and k(2) (together referred as k(i)) were measured under pse...

A comprehensive study of several atmospheric degradation routes for two hydrofluoroalcohols, CF(3)(CH(2))(x=1,2)CH(2)OH, is presented. The gas-phase kinetics of their reactions with hydroxyl radicals (OH) and chlorine (Cl) atoms are investigated by absolute and relative techniques, respectively. The room-temperature rate coefficients (±σ, in cm(3)...

The absolute rate coefficients for the tropospheric reactions of chlorine (Cl) atoms and hydroxyl (OH) radicals with CF3CH2CHO and CF3(CH2)2CHO were measured as a function of temperature (263-371 K) and pressure (50-215 Torr of He) by pulsed UV laser photolysis techniques. Vacuum UV resonance fluorescence was employed to detect and monitor the time...

Absolute rate coefficients for the gas-phase reactions of OH radical with 3-methylbutanal (k1), trans-2-methyl-2-butenal (k2), and 3-methyl-2-butenal (k3) have been obtained with the pulsed laser photolysis/laser-induced fluorescence technique. Gas-phase concentration of aldehydes was measured by UV absorption spectroscopy at 185 nm. Experiments we...

An evaluation of the environmental impact of stressed-induced compounds, 1-penten-3-ol,(Z)-3-hexen-1-ol, and 1-penten-3-one (ethyl vinyl ketone, EVK), is presented in this paper. The removal processes considered here are the gas-phase reactions with hydroxyl (OH) radicals and photolysis in the actinic region (above 290 nm). The wavelength dependenc...

The absolute rate coefficients for the tropospheric reactions of chlorine (Cl) atoms and hydroxyl (OH) radicals with CF3CH2CHO and CF3(CH2)2CHO were measured as a function of temperature (263–371 K) and pressure (50–215 Torr of He) by pulsed UV laser photolysis techniques. Vacuum UV resonance fluorescence was employed to detect and monitor the time...