T- and pH-dependent OH radical reaction kinetics with glycine, alanine, serine, and threonine in the aqueous phase

Wen, Liang; Schaefer, Thomas; Zhang, Yimu; He, Lin; Ventura, Oscar N.; Herrmann, Hartmut

doi:10.1039/d1cp05186e

Cited by 8 publications

(13 citation statements)

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“…Scheme illustrates the mechanism of the OH radical-induced H-atom abstraction reaction with tartaric acid and the possible electron transfer, with H-atom abstraction being the main reaction pathway. ,,, …”

Section: Resultsmentioning

confidence: 99%

“…Scheme 1 illustrates the mechanism of the OH radical-induced H-atom abstraction reaction with tartaric acid and the possible electron transfer, with H-atom abstraction being the main reaction pathway. 11,29,32,33 An alkyl radical is formed, which immediately reacts with O 2 to form an α-hydroxy peroxyl radical. 32,34 In this case, the αhydroxy peroxyl radical decomposes into an HO 2 radical and the corresponding carbonyl compound 2-hydroxy-3-oxosuccinic acid.…”

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

“…We would like to point out that care has to be taken for considering the internal filter effect when photolytic radical generation is used in combination with competition kinetics, and the reactants co-absorb at the photolysis wavelength used for radical generation, as outlined in former publications from our group. 20,21,23,24,33,36 As shown in Table 1, the kinetics of OH radicals of tartaric acid and mucic acid are affected by the pH of the solution, with the highest rate constants at pH Hence, the rate constants of k HA can be determined by the rate constants corrected for the internal filter effect (see Table…”

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

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Temperature- and pH- Dependent OH Radical Reaction Kinetics of Tartaric and Mucic Acids in the Aqueous Phase

et al. 2022

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Tartaric acid and mucic acid are dicarboxylic acids (DCAs), a substance class often found in atmospheric aerosols and cloud droplets. The hydroxyl radical ( • OH)-induced oxidation in the aqueous phase is known to be an important loss process of organic compounds such as DCAs. However, the study of • OH kinetics of DCAs in the aqueous phase is still incomplete. In the present study, the rate constants of the • OH reactions of tartaric acid and mucic acid in the aqueous phase were determined by the thiocyanate competition kinetics method as a function of temperature and pH. The following T-dependent Arrhenius expressions (in units of L mol −1 s −1 ) were first derived for the • OH reactions with tartaric acid�k(T, H 2 A) = (3.3 ± 0.1) × 10 10 exp[(−1350 ± 110 K)/T], k(T, HA − ) = (3.6 ± 0.1) × 10 10 exp[(−580 ± 110 K)/T], and k(T, A 2− ) = (3.3 ± 0.1) × 10 10 exp[(−1190 ± 170 K)/T]�as well as mucic acid�k(T, H 2 A) = (2.2 ± 0.1) × 10 10 exp[(−1140 ± 150 K)/T], k(T, HA − ) = (4.8 ± 0.1) × 10 10 exp[(−1280 ± 170 K)/T], and k(T, A 2− ) = (2.1 ± 0.1) × 10 10 exp[(−970 ± 70 K)/T]. A general trend of the • OH rate constant is found asThe pH-and temperaturedependent rate constants of the OH radical reactions allow an accurate description of the source and sink processes in the tropospheric aqueous phase.

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Section: Resultsmentioning

confidence: 99%

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

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Temperature- and pH- Dependent OH Radical Reaction Kinetics of Tartaric and Mucic Acids in the Aqueous Phase

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“…Several factors, such as free radicals, and ultraviolet radiation, may oxidize the amino acids in different environments. [6][7][8][9][10][11][12][13][14] Stadtman et al 6 investigated the oxidation of amino acids by hydroxyl radical (HO  ) produced by the Fenton reagent, i.e., -Fe(II)+H 2 O 2 system. The obtained products were NH 4 + , α-ketoacids, CO 2 , oximes, and aldehydes or carboxylic acids containing one less carbon atom.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, the reaction rates varied from 5×10 5 to 6×10 7 M -1 s -1 , with the decreasing order being the following: His > Trp > Tyr > Met. Wen et al 8 experimentally and theoretically performed the influences of temperature and pH on the oxidations of glycine (Gly), alanine (Ala), serine (Ser), and threonine (Thr) in the aqueous phase by HO • radical. The authors observed that the oxidation rate constants of these amino acids increased from 1.3 to 3 times when the temperature grew from 278 to 318K.…”

Section: Introductionmentioning

confidence: 99%

Influence of transition metal ions on the oxidation of L-proline amino acid initiated by HO● radical in the aqueous phase

Dao

Truong

Nguyen

2022

Preprint

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The oxidation of L-proline (Pro) amino acid by HO • radical and the influence of transition metal ions on this process have been investigated by using the density functional theory (DFT) method at the M05-2X/6-311++G(3df,3pd)//M05-2X/6-311++G(d,p) level of theory in the aqueous phase. The results show that Pro can be oxidized by HO • radical via formal hydrogen transfer (FHT) reactions at multiple sites, with the highest branching ratio found at hydrogen atoms H10 (30.04%) and H12 (25.60%). The overall rate constant at 298.15K is determined as 6.04 × 10 8 M -1 s -1 , and its expression from 250 to 400K is k=1.634×T 2.990 ×exp[1.591(kcal mol -1 )/RT] M -1 s -1 . In addition, Pro tends to form the stable mono-and bidentate complexes with both Fe and Cu ions via the-COO functional group of dipole-salt form, which significantly increases when the concentration of Pro doubles. The most stable Cu(II)-Pro complexes have high potential oxidant risks by enhancing the HO • radical formation when reducing agents such as superoxide anion, or ascorbate anion are available. Besides, the oxidant reaction of the high oxidation state complexes, including Fe(III)-Pro and Cu(II)-Pro, by HO • radical as FHT reactions have a lower rate constant than that of free-ligand, while the ones for SET reactions is extremely low even though they are higher than that of free-ligand. As a result, the Pro's oxidation enhancement of these complexes is negligible. In contrast, the rate constants of SET reactions of low oxidation state complexes (i.e., Fe(II)-Pro and Cu(I)-Pro) are likely to be many times faster than the oxidation rate of free ligand, and thus, these complexes promote the oxidation of Pro. Finally, the FHT chemical nature of HO-initiated oxidation for free Pro, Fe(III)-Pro, and Cu(II)-Pro complexes are evaluated to determine whether these processes occur via hydrogen atom transfer (HAT) or proton-coupled electron transfer (PCET).

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Temperature-Dependent Oxidation of Hydroxylated Aldehydes by ^•OH, SO₄^•–, and NO₃^• Radicals in the Atmospheric Aqueous Phase

Mekic,

Schaefer,

Hoffmann

et al. 2023

J. Phys. Chem. A

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T-dependent aqueous-phase rate constants were determined for the oxidation of the hydroxy aldehydes, glyceraldehyde, glycolaldehyde, and lactaldehyde, by the hydroxyl radicals (•OH), the sulfate radicals (SO4 •–), and the nitrate radicals (NO3 •). The obtained Arrhenius expressions for the oxidation by the •OH radical are: k (T,GLYCERALDEHYDE+OH•) = (3.3 ± 0.1) × 1010 × exp((−960 ± 80 K)/T)/L mol–1 s–1, k (T,GLYCOLALDEHYDE+OH•) = (4.3 ± 0.1) × 1011 × exp((−1740 ± 50 K)/T)/L mol–1 s–1, k (T,LACTALDEHYDE+OH•) = (1.6 ± 0.1) × 1011 × exp((−1410 ± 180 K)/T)/L mol–1 s–1; for the SO4 •– radical: k (T,GLYCERALDEHYDE+SO4 •–) = (4.3 ± 0.1) × 109 × exp((−1400 ± 50 K)/T)/L mol–1 s–1, k (T,GLYCOLALDEHYDE+SO4 •–) = (10.3 ± 0.3) × 109 × exp((−1730 ± 190 K)/T)/L mol–1 s–1, k (T,LACTALDEHYDE+SO4 •–) = (2.2 ± 0.1) × 109 × exp((−1030 ± 230 K)/T)/L mol–1 s–1; and for the NO3 • radical: k (T,GLYCERALDEHYDE+NO3 •) = (3.4 ± 0.2) × 1011 × exp((−3470 ± 460 K)/T)/L mol–1 s–1, k (T,GLYCOLALDEHYDE+NO3 •) = (7.8 ± 0.2) × 1011 × exp((−3820 ± 240 K)/T)/L mol–1 s–1, k (T,LACTALDEHYDE+NO3 •) = (4.3 ± 0.2) × 1010 × exp((−2750 ± 340 K)/T)/L mol–1 s–1, respectively. Targeted simulations of multiphase chemistry reveal that the oxidation by OH radicals in cloud droplets is important under remote and wildfire influenced continental conditions due to enhanced partitioning. There, the modeled average aqueous •OH concentration is 2.6 × 10–14 and 1.8 × 10–14 mol L–1, whereas it is 7.9 × 10–14 and 3.5 × 10–14 mol L–1 under wet particle conditions. During cloud periods, the aqueous-phase reactions by •OH contribute to the oxidation of glycolaldehyde, lactaldehyde, and glyceraldehyde by about 35 and 29%, 3 and 3%, and 47 and 37%, respectively.

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T- and pH-dependent OH radical reaction kinetics with glycine, alanine, serine, and threonine in the aqueous phase

Abstract: Glycine, alanine, serine, and threonine are essential amino acids originating from biological activities. These substances can be emitted into the atmosphere directly. Within the present study, the aqueous phase reaction...

Cited by 8 publications

References 75 publications

Temperature- and pH- Dependent OH Radical Reaction Kinetics of Tartaric and Mucic Acids in the Aqueous Phase

Temperature- and pH- Dependent OH Radical Reaction Kinetics of Tartaric and Mucic Acids in the Aqueous Phase

Influence of transition metal ions on the oxidation of L-proline amino acid initiated by HO● radical in the aqueous phase

Temperature-Dependent Oxidation of Hydroxylated Aldehydes by ^•OH, SO₄^•–, and NO₃^• Radicals in the Atmospheric Aqueous Phase

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T- and pH-dependent OH radical reaction kinetics with glycine, alanine, serine, and threonine in the aqueous phase

Abstract: Glycine, alanine, serine, and threonine are essential amino acids originating from biological activities. These substances can be emitted into the atmosphere directly. Within the present study, the aqueous phase reaction...

Cited by 8 publications

References 75 publications

Temperature- and pH- Dependent OH Radical Reaction Kinetics of Tartaric and Mucic Acids in the Aqueous Phase

Temperature- and pH- Dependent OH Radical Reaction Kinetics of Tartaric and Mucic Acids in the Aqueous Phase

Influence of transition metal ions on the oxidation of L-proline amino acid initiated by HO● radical in the aqueous phase

Temperature-Dependent Oxidation of Hydroxylated Aldehydes by •OH, SO4•–, and NO3• Radicals in the Atmospheric Aqueous Phase

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Temperature-Dependent Oxidation of Hydroxylated Aldehydes by ^•OH, SO₄^•–, and NO₃^• Radicals in the Atmospheric Aqueous Phase