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Veronica Vaida - One of the best experts on this subject based on the ideXlab platform.
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conformer specific photolysis of Pyruvic Acid and the effect of water
Journal of Physical Chemistry A, 2020Co-Authors: Sandra L Blair, Allison Reed E Harris, Veronica Vaida, Mathieu Cazaunau, Edouard Pangui, Jeanfrancois Doussin, Benjamin N Frandsen, Henrik G KjaergaardAbstract:The conformer specific reactivity of gas-phase Pyruvic Acid following the S1 (nπ*) ← S0 excitation at λmax = 350 nm (290-380 nm) and the effect of water is investigated for the two lowest energy conformers. Conformer specific gas-phase Pyruvic Acid photolysis rate constants and their respective populations are measured by monitoring their distinct vibrational OH-stretching frequencies. The geometry, relative energies, fundamental vibrational frequencies, and electronic transitions of the Pyruvic Acid conformers and their monohydrated complexes are calculated with density functional theory and ab initio methods. Results from experiment and theory show that the more stable conformer with an intramolecular hydrogen bond dominates the gas-phase photolysis of Pyruvic Acid. Water greatly affects the gas-phase Pyruvic Acid conformer population and photochemistry through hydrogen bonding interactions. The addition of water decreases the gas-phase relative population of the more stable conformer and decreases the ...
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heterogeneous interactions between gas phase Pyruvic Acid and hydroxylated silica surfaces a combined experimental and theoretical study
Journal of Physical Chemistry A, 2019Co-Authors: Yuan Fang, Veronica Vaida, Dominika Lesnicki, Kristin J Wall, Mariepierre Gaigeot, Marialore Sulpizi, Vicki H GrassianAbstract:The adsorption of gas-phase Pyruvic Acid (CH3COCOOH) on hydroxylated silica particles has been investigated at 296 K using transmission Fourier transform infrared (FTIR) spectroscopy and theoretical simulations. Under dry conditions (<1% relative humidity, RH), both the trans–cis (Tc) and trans–trans (Tt) Pyruvic Acid conformers are observed on the surface as well as the (hydrogen bonded) Pyruvic Acid dimer. The detailed surface interactions were further understood through ab initio molecular dynamics simulations. Under higher relative humidity conditions (above 10% RH), adsorbed water competes for surface adsorption sites. Adsorbed water is also observed to change the relative populations of the different adsorbed Pyruvic Acid configurations. Overall, this study provides valuable insights into the interaction of Pyruvic Acid with hydroxylated silica surfaces on the molecular level from both experimental and theoretical analyses. Furthermore, these results highlight the importance of the environment (rela...
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Atmospheric Simulation Chamber Studies of the Gas-Phase Photolysis of Pyruvic Acid.
Journal of Physical Chemistry A, 2017Co-Authors: Allison E. Reed Harris, Mathieu Cazaunau, Aline Gratien, Edouard Pangui, Jeanfrancois Doussin, Veronica VaidaAbstract:Pyruvic Acid is an atmospherically abundant α-keto-Acid that degrades efficiently from the troposphere via gas-phase photolysis. To explore conditions relevant to the environment, 2–12 ppm Pyruvic Acid is irradiated by a solar simulator in the environmental simulation chamber, CESAM. The combination of the long path length available in the chamber and its low surface area to volume ratio allows us to quantitatively examine the quantum yield and photochemical products of Pyruvic Acid. Such details are new to the literature for the low initial concentrations of Pyruvic Acid employed here. We determined photolysis quantum yields of ϕobsN2 = 0.84 ± 0.1 in nitrogen and ϕobsAir = 3.2 ± 0.5 in air, which are higher than those reported by previous studies that used higher partial pressures of Pyruvic Acid. The quantum yield greater than unity in air is due to secondary chemistry, driven by O2, that emerges under the conditions in these experiments. The low concentration of Pyruvic Acid and the resulting oxygen ef...
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mechanistic description of photochemical oligomer formation from aqueous Pyruvic Acid
Journal of Physical Chemistry A, 2017Co-Authors: Rebecca J Rapf, Russell J Perkins, Barry K Carpenter, Veronica VaidaAbstract:The aqueous phase photochemistry of Pyruvic Acid, an important oxidation product of isoprene, is known to generate larger oligomeric species that may contribute to the formation of secondary organic aerosol in the atmosphere. Using high resolution negative mode electrospray ionization mass spectrometry, the aqueous photochemistry of dilute solutions of Pyruvic Acid (10, 1, and 0.5 mM) under anaerobic conditions was investigated. Even at the lowest concentration, covalently bonded dimers and trimers of Pyruvic Acid were observed as photochemical products. We calculate that it is energetically possible to photochemically generate paraPyruvic Acid, a dimer of Pyruvic Acid that is known to form via dark oligomerization processes. Subsequent photochemical reactions of paraPyruvic Acid with Pyruvic Acid form larger oligomeric products, such as 2,4-dihydroxy-2-methyl-5-oxohexanoic Acid. A robust and relatively simple photochemical mechanism is discussed that explains both the conditional dependence and wide arra...
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multiphase photochemistry of Pyruvic Acid under atmospheric conditions
Journal of Physical Chemistry A, 2017Co-Authors: Allison Reed E Harris, Elizabeth C Griffith, Anne Monod, Aki Pajunoja, Mathieu Cazaunau, Aline Gratien, Edouard Pangui, Annele Virtanen, Jeanfrancois Doussin, Veronica VaidaAbstract:Aerosol and molecular processing in the atmosphere occurs in a complex and variable environment consisting of multiple phases and interfacial regions. To explore the effects of such conditions on the reactivity of chemical systems, we employ an environmental simulation chamber to investigate the multiphase photolysis of Pyruvic Acid, which photoreacts in the troposphere in aqueous particles and in the gas phase. Upon irradiation of nebulized Pyruvic Acid, acetic Acid and carbon dioxide are rapidly generated, which is consistent with previous literature on the bulk phase photolysis reactions. Additionally, we identify a new C6 product, zymonic Acid, a species that has not previously been reported from Pyruvic Acid photolysis under any conditions. Its observation here, and corresponding spectroscopic signatures, indicates it could be formed by heterogeneous reactions at the droplet surface. Prior studies of the aqueous photolysis of Pyruvic Acid have shown that high-molecular-weight compounds are formed via...
Allison Reed E Harris - One of the best experts on this subject based on the ideXlab platform.
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conformer specific photolysis of Pyruvic Acid and the effect of water
Journal of Physical Chemistry A, 2020Co-Authors: Sandra L Blair, Allison Reed E Harris, Veronica Vaida, Mathieu Cazaunau, Edouard Pangui, Jeanfrancois Doussin, Benjamin N Frandsen, Henrik G KjaergaardAbstract:The conformer specific reactivity of gas-phase Pyruvic Acid following the S1 (nπ*) ← S0 excitation at λmax = 350 nm (290-380 nm) and the effect of water is investigated for the two lowest energy conformers. Conformer specific gas-phase Pyruvic Acid photolysis rate constants and their respective populations are measured by monitoring their distinct vibrational OH-stretching frequencies. The geometry, relative energies, fundamental vibrational frequencies, and electronic transitions of the Pyruvic Acid conformers and their monohydrated complexes are calculated with density functional theory and ab initio methods. Results from experiment and theory show that the more stable conformer with an intramolecular hydrogen bond dominates the gas-phase photolysis of Pyruvic Acid. Water greatly affects the gas-phase Pyruvic Acid conformer population and photochemistry through hydrogen bonding interactions. The addition of water decreases the gas-phase relative population of the more stable conformer and decreases the ...
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multiphase photochemistry of Pyruvic Acid under atmospheric conditions
Journal of Physical Chemistry A, 2017Co-Authors: Allison Reed E Harris, Elizabeth C Griffith, Anne Monod, Aki Pajunoja, Mathieu Cazaunau, Aline Gratien, Edouard Pangui, Annele Virtanen, Jeanfrancois Doussin, Veronica VaidaAbstract:Aerosol and molecular processing in the atmosphere occurs in a complex and variable environment consisting of multiple phases and interfacial regions. To explore the effects of such conditions on the reactivity of chemical systems, we employ an environmental simulation chamber to investigate the multiphase photolysis of Pyruvic Acid, which photoreacts in the troposphere in aqueous particles and in the gas phase. Upon irradiation of nebulized Pyruvic Acid, acetic Acid and carbon dioxide are rapidly generated, which is consistent with previous literature on the bulk phase photolysis reactions. Additionally, we identify a new C6 product, zymonic Acid, a species that has not previously been reported from Pyruvic Acid photolysis under any conditions. Its observation here, and corresponding spectroscopic signatures, indicates it could be formed by heterogeneous reactions at the droplet surface. Prior studies of the aqueous photolysis of Pyruvic Acid have shown that high-molecular-weight compounds are formed via...
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photochemical kinetics of Pyruvic Acid in aqueous solution
Journal of Physical Chemistry A, 2014Co-Authors: Allison Reed E Harris, Barbara Ervens, Richard K Shoemaker, Jay A Kroll, Rebecca J Rapf, Elizabeth C Griffith, Anne Monod, Veronica VaidaAbstract:Pyruvic Acid in the atmosphere is found in both the gas and aqueous phases, and its behavior gives insight into that of other α-keto Acids. Photolysis is a significant degradation pathway for this molecule in the environment, and in aqueous solution the major photoproducts are higher-molecular-weight compounds that may contribute to secondary organic aerosol mass. The kinetics of the aqueous-phase photolysis of Pyruvic Acid under aerobic and anaerobic conditions was investigated in order to calculate the first-order rate constant, Jaq, in solution. Analysis of the exponential decay of Pyruvic Acid was performed by monitoring both Pyruvic Acid and its photolytic products over the course of the reaction by 1H NMR spectroscopy. Detection of major and minor products in the 0.1, 0.05, and 0.02 M Pyruvic Acid photolyses clearly demonstrates that the primary reaction pathways are highly dependent on the initial Pyruvic Acid concentration and the presence of dissolved oxygen. The Jaq values were calculated with a...
Song Yong Lun - One of the best experts on this subject based on the ideXlab platform.
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Biotechnological production of Pyruvic Acid
Applied Microbiology and Biotechnology, 2001Co-Authors: Y.x. Li, Y. Li, Jie Chen, Song Yong LunAbstract:Pyruvic Acid is an important organic Acid widely used in the chemical and drug, as well as agrochemical, industries. Compared with the chemical method, biotechnological production of Pyruvic Acid is an alternative approach because of the low cost. An overview of biotechnological production of pyruvate, including direct fermentative production employing eukaryotic and prokaryotic microorganisms, production by a resting cell method and an enzymatic method as well as the recovery of pyruvate, is discussed. A multi-vitamin auxotrophic yeast strain, Torulopsis glabrata. has been used in the commercial production of pyruvate; emphasis is therefore placed on the mechanism and characteristics of pyruvate production by this strain.
Amit Keshav - One of the best experts on this subject based on the ideXlab platform.
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Production and Recovery of Pyruvic Acid: Recent Advances
Journal of The Institution of Engineers (India): Series E, 2017Co-Authors: Amit Keshav, Bidyut Mazumdar, Awanish Kumar, Hasan UsluAbstract:Pyruvic Acid is an important keto-carboxylic Acid and can be manufactured by both chemical synthesis and biotechnological routes. In the present paper an overview of recent developments and challenges in various existing technique for the production and recovery of Pyruvic Acid from fermentation broth or from waste streams has been presented. The main obstacle in biotechnological production of Pyruvic Acid is development of suitable microorganism which can provide high yield and selectivity. On the other hand, technical limitation in recovery of Pyruvic Acid from fermentation broth is that, it could not be separated as other carboxylic Acid in the form of salts by addition of alkali. Besides, Pyruvic Acid cannot be crystallized. Commercial separation by distillation is very expensive because Pyruvic Acid decomposes at higher temperature. It is also chemically reactive due to its peculiar molecular structure and has tendency to polymerize. Thus, at high concentration the various type of reaction leads to lower yield of the product, and hence, conventional methods are not favorable. Alternate separation technologies viable to both synthetic and biological routes are the current research areas. Latest techniques such as reactive extraction is new to the field of recovery of Pyruvic Acid. Recent development and future prospects in downstream processing of biochemically produced Pyruvic Acids has been discussed in this review article.
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extraction equilibria of Pyruvic Acid using tri n butyl phosphate influence of diluents
Journal of Chemical & Engineering Data, 2014Co-Authors: Amit KeshavAbstract:Pyruvic Acid is extensively utilized in the chemical, pharmaceutical, and agrochemical industries. Novel biotechnological routes to Pyruvic Acid production receiving great attention and recent focus of research are toward its separation from fermentation broth or recovery from waste streams. Based on reversible complexation, extraction equilibria of the system (water + Pyruvic Acid + extractant/diluents) were measured at T = 308.2 K using various concentrations of Pyruvic Acid (0.1 kmol·m–3 to 0.5 kmol·m–3) and extractant (tri-n-butyl phosphate, TBP) (0.36 kmol·m–3 to 2.56 kmol·m–3) in different diluents (n-heptane, toluene, and methyl-iso-butyl ketone, MIBK). Different physiochemical properties such as dipole moment and ET parameter have been used for comparison. Results are given in terms of various parameters such as distribution coefficient, equilibrium complexation constant, loading ratio and extraction efficiency. Using expressions derived for extraction equilibria, equilibrium complexation constant...
Jeanfrancois Doussin - One of the best experts on this subject based on the ideXlab platform.
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conformer specific photolysis of Pyruvic Acid and the effect of water
Journal of Physical Chemistry A, 2020Co-Authors: Sandra L Blair, Allison Reed E Harris, Veronica Vaida, Mathieu Cazaunau, Edouard Pangui, Jeanfrancois Doussin, Benjamin N Frandsen, Henrik G KjaergaardAbstract:The conformer specific reactivity of gas-phase Pyruvic Acid following the S1 (nπ*) ← S0 excitation at λmax = 350 nm (290-380 nm) and the effect of water is investigated for the two lowest energy conformers. Conformer specific gas-phase Pyruvic Acid photolysis rate constants and their respective populations are measured by monitoring their distinct vibrational OH-stretching frequencies. The geometry, relative energies, fundamental vibrational frequencies, and electronic transitions of the Pyruvic Acid conformers and their monohydrated complexes are calculated with density functional theory and ab initio methods. Results from experiment and theory show that the more stable conformer with an intramolecular hydrogen bond dominates the gas-phase photolysis of Pyruvic Acid. Water greatly affects the gas-phase Pyruvic Acid conformer population and photochemistry through hydrogen bonding interactions. The addition of water decreases the gas-phase relative population of the more stable conformer and decreases the ...
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Atmospheric Simulation Chamber Studies of the Gas-Phase Photolysis of Pyruvic Acid.
Journal of Physical Chemistry A, 2017Co-Authors: Allison E. Reed Harris, Mathieu Cazaunau, Aline Gratien, Edouard Pangui, Jeanfrancois Doussin, Veronica VaidaAbstract:Pyruvic Acid is an atmospherically abundant α-keto-Acid that degrades efficiently from the troposphere via gas-phase photolysis. To explore conditions relevant to the environment, 2–12 ppm Pyruvic Acid is irradiated by a solar simulator in the environmental simulation chamber, CESAM. The combination of the long path length available in the chamber and its low surface area to volume ratio allows us to quantitatively examine the quantum yield and photochemical products of Pyruvic Acid. Such details are new to the literature for the low initial concentrations of Pyruvic Acid employed here. We determined photolysis quantum yields of ϕobsN2 = 0.84 ± 0.1 in nitrogen and ϕobsAir = 3.2 ± 0.5 in air, which are higher than those reported by previous studies that used higher partial pressures of Pyruvic Acid. The quantum yield greater than unity in air is due to secondary chemistry, driven by O2, that emerges under the conditions in these experiments. The low concentration of Pyruvic Acid and the resulting oxygen ef...
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multiphase photochemistry of Pyruvic Acid under atmospheric conditions
Journal of Physical Chemistry A, 2017Co-Authors: Allison Reed E Harris, Elizabeth C Griffith, Anne Monod, Aki Pajunoja, Mathieu Cazaunau, Aline Gratien, Edouard Pangui, Annele Virtanen, Jeanfrancois Doussin, Veronica VaidaAbstract:Aerosol and molecular processing in the atmosphere occurs in a complex and variable environment consisting of multiple phases and interfacial regions. To explore the effects of such conditions on the reactivity of chemical systems, we employ an environmental simulation chamber to investigate the multiphase photolysis of Pyruvic Acid, which photoreacts in the troposphere in aqueous particles and in the gas phase. Upon irradiation of nebulized Pyruvic Acid, acetic Acid and carbon dioxide are rapidly generated, which is consistent with previous literature on the bulk phase photolysis reactions. Additionally, we identify a new C6 product, zymonic Acid, a species that has not previously been reported from Pyruvic Acid photolysis under any conditions. Its observation here, and corresponding spectroscopic signatures, indicates it could be formed by heterogeneous reactions at the droplet surface. Prior studies of the aqueous photolysis of Pyruvic Acid have shown that high-molecular-weight compounds are formed via...
