Ozonolysis of β-Caryophyllonic and Limononic Acids in the Aqueous Phase: Kinetics, Product Yield, and Mechanism

Witkowski, Bartłomiej; Alsharafi, Mohammed; Gierczak, Tomasz

doi:10.1021/acs.est.9b02471

Cited by 14 publications

(11 citation statements)

References 61 publications

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“…The m / z 153.07 ion can be converted to a quinone compound, which can also undergo esterification pathways in the presence of CH 3 OH. These pathways are often observed in photochemical processes. ,, Clearly, the VA + OH reaction might result in formation of other products, but they are most likely not detected here due to the limitations of the LC-MS instrument and its separation column.…”

Section: Results and Discussionmentioning

confidence: 94%

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Aqueous-Phase Photooxidation of Vanillic Acid: A Potential Source of Humic-Like Substances (HULIS)

Tang

Tsona

et al. 2020

ACS Earth Space Chem.

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Phenolic compounds are emitted in large amounts from biomass burning and can undergo aqueous-phase reactions in the atmosphere to form secondary organic aerosols (aqSOA). In this study, the kinetics and products of the reaction of vanillic acid (VA) with hydroxyl radicals (OH) were characterized, and their formation mechanisms were determined using ultrahigh-performance liquid chromatography ultraviolet/mass spectrometry (HPLC-UV/MS) and UV−vis absorption and fluorescence spectroscopies. The obtained rate constants of the VA + OH reaction are (9.8 ± 1.5) × 10 9 and (3.8 ± 0.7) × 10 9 M −1 s −1 at pH 2 and 10, respectively. A yellowish solution is obtained after illumination, and it absorbs in the UV−vis region and has an unusual fluorescence spectrum, which suggests formation of a humic-like substance (HULIS) by the C−C and C−O coupling of phenoxyl radicals. Additionally, hydroxylation of the aromatic ring occurs through OH addition, which increases the degree of oxidation of the products. This study indicates that the aqueous-phase OH oxidation of phenolic acid compounds may contribute to formation of HULIS in the atmosphere, especially in areas with active burning of biomass. The high-molecular-weight products would remain in the particle phase after fog/cloud evaporation and influence the chemical and optical properties of atmospheric particles.

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Section: Results and Discussionmentioning

confidence: 94%

“…These pathways are often observed in photochemical processes. 4,30,63 Clearly, the VA + OH reaction might result in formation of other products, but they are most likely not detected here due to the limitations of the LC-MS instrument and its separation column.…”

Section: ■ Introductionmentioning

confidence: 96%

Aqueous-Phase Photooxidation of Vanillic Acid: A Potential Source of Humic-Like Substances (HULIS)

Tang

Tsona

et al. 2020

ACS Earth Space Chem.

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“…A large amount of water dispersed in the atmosphere (i.e., cloud, fog, and aerosol liquid water) makes it an important reaction medium for the further processing of α-pinene oxidation products. − In recent years, the atmospheric aqueous-phase has been recognized as an important reaction media for the processing of water-soluble organic compounds. − Atmospheric models suggest that through these processes contribute to global annual SOA production with 20 to 30 Tg year –1 . ,,,− In contrast to the gas-phase processes, aqueous-phase reactions leading to SOA are vaguely recognized, posing a great challenge for researchers in recent years …”

Section: Introductionmentioning

confidence: 99%

Physicochemical Properties of Terebic Acid, MBTCA, Diaterpenylic Acid Acetate, and Pinanediol as Relevant α-Pinene Oxidation Products

et al. 2020

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The physicochemical properties and the synthesis of four α-pinene oxidation products, terebic acid, 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), diaterpenylic acid acetate (DTAA), and pinanediol, are presented in this study. The physicochemical properties encompass thermal properties, solubility in water, and dissociation constant (pK a ) for the investigated compounds. It was found that terebic acid exhibits a relatively high melting temperature of 449.29 K, whereas pinanediol revealed a low melting temperature of 329.26 K. The solubility in water was determined with the dynamic method and the experimental results were correlated using three different mathematical models: Wilson, NRTL, and UNIQUAC equations. The results of the correlation indicate that the Wilson equation appears to work the best for terebic acid and pinanediol. The calculated standard deviation was for 3.79 for terebic acid and 1.25 for pinanediol. In contrast, UNIQUAC was the best mathematical model for DTAA and MBTCA. The calculated standard deviation was 0.57 for DTAA and 2.21 for MBTCA. The measured water solubility increased in the following order: pinanediol > DTAA ≥ MBTCA > terebic acid, which affects their multiphase aging chemistry in the atmosphere. Moreover, acidity constants (pK a ) at 298, 303, and 308 K were determined for DTAA with the Bates−Schwarzenbach spectrophotometric method. The pK a values obtained at 298, 303, and 308 K were found to be 3. 76, 3.85, and 3.88, respectively.

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“…This is likely because the rate coefficient of the OAs determined by the relative kinetic method depends strictly on the reference compound k OH ΙΙ values. We are aware that Witkowski et al ,, conducted a series of studies on monoterpene-related compounds and have been using a different reference value for pimelic acid’s rate constant under acidic conditions ( k OH ΙΙ = 3.5 × 10 –9 M –1 s –1 ). When we used this reference k OH ΙΙ value, we also obtained very similar CPA k OH ΙΙ values across the three pH conditions (i.e., in agreement with Witkowski et al).…”

Section: Resultsmentioning

confidence: 99%

pH Dependence of the OH Reactivity of Organic Acids in the Aqueous Phase

Amorim

Klimchuk

et al. 2020

Environ. Sci. Technol.

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Photochemical processing taking place in atmospheric aqueous phases serves as both a source and a sink of organic compounds. In aqueous environments, acid–base chemistry and, by extension, aqueous-phase pH, are an important yet often neglected factors to consider when investigating the kinetics of organic compounds. We have investigated the aqueous-phase OH-oxidation of pinic acid, cis-pinonic acid, limononic acid, and formic acid (FA) as a function of pH. We have also extended our studies to other organic acids (OAs) present in the water-soluble fraction of secondary organic aerosol (SOA) arising from the ozonolysis of α-pinene. Although all the OAs exhibited larger OH reactivities at pH 10, the pH dependence was dramatically different between FA, the smallest OA, and those that contained more than eight carbons. A kinetic box model was also employed to characterize our photoreactor and to provide confidence to our results. Our finding shows that the atmospheric lifetimes of small OAs (e.g., FA) are highly sensitive to cloud water pH. However, those of larger OAs and many other OAs in α-pinene SOA are affected to a much less extent. These results are of great importance for the simplification of cloud water chemistry models.

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Ozonolysis of β-Caryophyllonic and Limononic Acids in the Aqueous Phase: Kinetics, Product Yield, and Mechanism

Cited by 14 publications

References 61 publications

Aqueous-Phase Photooxidation of Vanillic Acid: A Potential Source of Humic-Like Substances (HULIS)

Aqueous-Phase Photooxidation of Vanillic Acid: A Potential Source of Humic-Like Substances (HULIS)

Physicochemical Properties of Terebic Acid, MBTCA, Diaterpenylic Acid Acetate, and Pinanediol as Relevant α-Pinene Oxidation Products

pH Dependence of the OH Reactivity of Organic Acids in the Aqueous Phase

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