Liquid phase oxidation of α‐pinene initiated by ozone. 2: Formation of verbenol, verbenone and acid products

Martín, Juan Vicente González; Beltrán, Fernando J.; Frades, J.

doi:10.1002/ceat.270170307

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…The radicals are certain to take part in the initiation reaction (16,18). Thus, the rate of initiation increases proportionally to the amount of hydroperoxide generated by the oxidation.…”

Section: Construction Of Kinetic Modelmentioning

confidence: 98%

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Kinetic model for autoxidation of β‐carotene in organic solutions

Takahashi

Shibasaki‐Kitakawa

Yonemoto

1999

J Americ Oil Chem Soc

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Autoxidation of β-carotene was studied experimentally using n-decane as a solvent under various reaction conditions of temperature and dissolved oxygen concentration. A novel kinetic model was proposed on the basis of an autocatalytic free-radical chain reaction mechanism. A secondary initiation reaction by decomposition of hydroperoxide and reactions concerned with a β-carotene-derived C-centered radical in propagation and termination processes were taken into consideration in the model. There were four unknown kinetic constants, and the constants were estimated by fitting the model with the experimental data. The fitted results are in good agreement with the experimental data in all stages of the kinetics of autoxidation and over a wide range of oxygen concentrations. The model described not only the appearance of the induction stage but also the effect of the oxygen concentration on the autoxidation rate. In addition, the model predicted the behavior of autoxidation in another solvent at low temperature that had been reported by other researchers.Paper no. J8856 in JAOCS 76, 897-903 (August 1999). MODEL FOR AUTOXIDATION OF β-CAROTENE 903 JAOCS, Vol. 76, no. 8 (1999) FIG. 6. Experimental data reported by Tanaka (24), and results simulated by the models: broken line, the model proposed by Kasaikina et al. (12,13); solid line, the Novel Model.

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“…The radicals are certain to take part in the initiation reaction (16,18). Thus, the rate of initiation increases proportionally to the amount of hydroperoxide generated by the oxidation.…”

Section: Construction Of Kinetic Modelmentioning

confidence: 98%

“…In assuming the pseudo-steady-state for the formation rates of the respective radicals in the system, the consumption rate of β-carotene is [17] [ 18] where w i , a, and k′ in Equation 17 are given as follows: [19] [20] [21] where C AOOH is the concentration of hydroperoxide.…”

Section: Construction Of Kinetic Modelmentioning

confidence: 99%

Kinetic model for autoxidation of β‐carotene in organic solutions

Takahashi

Shibasaki‐Kitakawa

Yonemoto

1999

J Americ Oil Chem Soc

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“…The liquid-phase reaction between a-pinene and ozone has been studied previously 79,80 and the major product detected was a hydroperoxide followed by verbenol, verbonone and pinoic acid. The Raman spectrum presented in Fig.…”

Section: Products and Mechanism Of A-pinene Oxidation By Ozonementioning

confidence: 99%

Oxidation of biogenic and water-soluble compounds in aqueous and organic aerosol droplets by ozone: a kinetic and product analysis approach using laser Raman tweezers

et al. 2008

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The results of an experimental study into the oxidative degradation of proxies for atmospheric aerosol are presented. We demonstrate that the laser Raman tweezers method can be used successfully to obtain uptake coefficients for gaseous oxidants on individual aqueous and organic droplets, whilst the size and composition of the droplets is simultaneously followed. A laser tweezers system was used to trap individual droplets containing an unsaturated organic compound in either an aqueous or organic (alkane) solvent. The droplet was exposed to gas-phase ozone and the reaction kinetics and products followed using Raman spectroscopy. The reactions of three different organic compounds with ozone were studied: fumarate anions, benzoate anions and alpha-pinene. The fumarate and benzoate anions in aqueous solution were used to represent components of humic-like substances, HULIS; alpha-pinene in an alkane solvent was studied as a proxy for biogenic aerosol. The kinetic analysis shows that for these systems the diffusive transport and mass accommodation of ozone is relatively fast, and that liquid-phase diffusion and reaction are the rate determining steps. Uptake coefficients, gamma, were found to be (1.1 +/- 0.7) x 10(-5), (1.5 +/- 0.7) x 10(-5) and (3.0-7.5) x 10(-3) for the reactions of ozone with the fumarate, benzoate and alpha-pinene containing droplets, respectively. Liquid-phase bimolecular rate coefficients for reactions of dissolved ozone molecules with fumarate, benzoate and alpha-pinene were also obtained: kfumarate = (2.7 +/- 2) x 10(5), kbenzoate = (3.5 +/- 3) x 10(5) and kalpha-pinene = (1-3) x 10(7) dm3 mol(-1) s(-1). The droplet size was found to remain stable over the course of the oxidation process for the HULIS-proxies and for the oxidation of alpha-pinene in pentadecane. The study of the alpha-pinene/ozone system is the first using organic seed particles to show that the hygroscopicity of the particle does not increase dramatically over the course of the oxidation. No products were detected by Raman spectroscopy for the reaction of benzoate ions with ozone. One product peak, consistent with aqueous carbonate anions, was observed when following the oxidation of fumarate ions by ozone. Product peaks observed in the reaction of ozone with alpha-pinene suggest the formation of new species containing carbonyl groups.

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Monoterpenoids

Grayson¹

1997

Nat. Prod. Rep.

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Liquid phase oxidation of α‐pinene initiated by ozone. 2: Formation of verbenol, verbenone and acid products

Cited by 6 publications

References 17 publications

Kinetic model for autoxidation of β‐carotene in organic solutions

Kinetic model for autoxidation of β‐carotene in organic solutions

Oxidation of biogenic and water-soluble compounds in aqueous and organic aerosol droplets by ozone: a kinetic and product analysis approach using laser Raman tweezers

Monoterpenoids

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