The Simultaneous Determination of Bis(hydroxymethyl)-peroxide (BHMP), Hydroxymethylhydroperoxide (HMP), and H2O2 with Titanium(IV). Equilibria Between the Peroxides and the Stabilities of HMP and BHMP at Physiological Conditions.

Marklund, Stefan L.; Ikeuchi, Hiroyuki; Dhabanandana, S.; Krogh-Moe, J.; Koyamada, Koji; Kachi, Sukeji

doi:10.3891/acta.chem.scand.25-3517

Cited by 67 publications

(51 citation statements)

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“…Since Marklund 50 found that HMHP reacts with CH 2 (OH) 2 , it is possible that other hydroperoxides will react with CH 2 (OH) 2 in a similar manner. In experiment 6, when MgSO 4 &H 2 SO 4 seed aerosol was added to the chamber, a small amount of m/z = (-) 233, (-) 278…”

Section: S43 Potential Influence Of Ch 2 Omentioning

confidence: 99%

Isoprene NO₃ Oxidation Products from the RO₂ + HO₂ Pathway

et al. 2015

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S1.0 KINETIC MECHANISM DEVELOPMENT.A kinetic mechanism is formulated to simulate the reaction conditions of these experiments.The reactions included are listed in the Appendix (Table SA2, SA3, and SA4). Table SA5 contains a list of the abbreviations used. Rate constants for most of the reactions included in the mechanism are based on recommendations from JPL 1 , IUPAC 2-3 , or MCM v3.2 4 . However, some rate constants and branching ratios are not known. For these, we use our best judgement based on available data; explanations of the assumptions on which these estimates are based are included in this section. Some branching ratios and rate constants are estimated based on the experimental results presented here. Many of these branching ratios depend on the fraction of δ-and β-isomers that form (Table 3 and 5), which will likely depend on the lifetime of the RO 2 radical (Section 4.1). Thus, the reaction products and rates presented here are most consistent with the experimental results for this study in which the overall RO 2 lifetime was ~ 30 s. The kinetic mechanism developed here represents our current level of understanding, and deviations from the experimental results highlight areas for future study. S1.1. Basic Reactions in Kinetic Mechanism. HO 2 was constrained in the kinetic mechanism by the measured H 2 O 2 production rate. Prior to photooxidation, H 2 O 2 is predominantly formed from HO 2 + HO 2 reactions. To match the observed H 2 O 2 production rate in experiments 5, 6, and 8, we arbitrarily increased the reaction rate constant for CH 2 O + NO 3 by a factor of 2.5-3 in the kinetic mechanism above that recommended by IUPAC. Although not perfect when correcting for the missing HO 2 in this manner, the H 2 O 2 curves for the kinetic mechanism and the experimental results were fairly consistent. Under-prediction of HO 2 could be caused by other S3 missing chemistry including unaccounted for surface chemistry, later generation chemistry not incorporated into the kinetic mechanism, or many other possibilities. Here, we are confident that there is a missing source of HO 2 , but are agnostic about the mechanism responsible.Because the predominant loss of isoprene is due to reaction with NO 3 , the measured isoprene decay rate was used to constrain the amount of NO 3 present. Cantrell et al. 5 proposed that N 2 O 5would react with water present on the wall surface to form nitric acid even under dry conditions.We included a wall loss rate for N 2 O 5 (i.e., NO 3 loss rate) such that the isoprene decay in the kinetic mechanism matched with experimental results. This rate constant is chamber/experiment specific. For experiment 5 (24 m 3 , 2.2 ppm CH 2 O), 6 (24 m 3 , 4.7 ppm CH 2 O), 7 (1 m 3 , 2 ppm CH 2 O) and 8 (1 m 3 , 4 ppm CH 2 O), N 2 O 5 wall loss rate constants that best fit experimental conditions were 1.5 x 10 -4 , 12 x 10 -4 , 6 x 10 -4 and 12 x 10 -4 s -1 , respectively. We observe that the N 2 O 5 loss rate appears to be sensitive to both the mixing ratio of CH 2 O and the chamber.However, it s...

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Section: S43 Potential Influence Of Ch 2 Omentioning

confidence: 99%

Isoprene NO₃ Oxidation Products from the RO₂ + HO₂ Pathway

et al. 2015

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“…The hydrolysis of HMHP was followed and was used to determine the sum of the concentrations of HMHP and BHMP. At pH 8.5, the base-catalyzed hydrolysis of BHMP instantaneously generates HMHP [15]. In the pH 8.5 experiment, the observed concentration of HMHP is the sum of the original concentrations of HMHP and BHMP in the mixed peroxide solution.…”

Section: Resultsmentioning

confidence: 99%

“…Kinetics of the base-catalyzed hydrolysis of HMHP at pH 8.5 were studied by measuring the absorbance over a 15-min time span after reaction with Ti(IV)OSO 4 s −1 , and slightly faster than that observed by Marklund [15]. The hydrolysis rate of HMHP was examined to confirm the utility of the method to differentiate the peroxides.…”

Section: Resultsmentioning

confidence: 99%

“…Under the experimental conditions used in this study, Ti(IV) exists as TiO 2+ (aq) [18] complexed with SO 2− 4 ion in 1.0 M H 2 SO 4 . The kinetics of the formation of the titanium peroxide complex when Ti(IV)OSO 4 is added to a solution containing peroxide have been used to distinguish hydrogen peroxide from hydroxymethyl hydroperoxide in an earlier study [15]. However, no detailed information regarding the rate constants and energetics for the reactions were presented.…”

Section: Bhmp Hmhpmentioning

confidence: 99%

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The kinetics of complex formation between Ti(IV) and hydrogen peroxide

O’Sullivan

Tyree

2007

Int J of Chemical Kinetics

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The kinetics of the formation of the titanium-peroxide [TiO 2+ 2 ] complex from the reaction of Ti(IV)OSO 4 with hydrogen peroxide and the hydrolysis of hydroxymethyl hydroperoxide (HMHP) were examined to determine whether Ti(IV)OSO 4 could be used to distinguish between hydrogen peroxide and HMHP in mixed solutions. Stopped-flow analysis coupled to UV-vis spectroscopy was used to examine the reaction kinetics at various temperatures. The molar absorptivity (ε) of the [TiO 2+ 2 ] complex was found to be 679.5 ± 20.8 L mol −1 cm −1 at 405 nm. The reaction between hydrogen peroxide and Ti(IV)OSO 4 was first order with respect to both Ti(IV)OSO 4 and H 2 O 2 with a rate constant of 5.70 ± 0.18 × 10 4 M −1 s −1 at 25 • C, and an activation energy, E a = 40.5 ± 1.9 kJ mol −1 . The rate constant for the hydrolysis of HMHP was 4.3 × 10 −3 s −1 at pH 8.5. Since the rate of complex formation between Ti(IV)OSO 4 and hydrogen peroxide is much faster than the rate of hydrolysis of HMHP, the Ti(IV)OSO 4 reaction coupled to time-dependent UV-vis spectroscopic measurements can be used to distinguish between hydrogen peroxide and HMHP in solution.

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“…The concentration of this stock solution was determined by titration with potassium permanganate that was standardized by its reaction with sodium oxalate (Na 2 C 2 O 4 ). HMHP was synthesized from H 2 O 2 and HCHO solutions (Lee et al 1993;Marklund, 1971;Lee et al 2000). In case excess amount of HCHO was present, the synthetic mixture was composed of HMHP with some H 2 O 2 and bis-HMP.…”

Section: Reagents and Standardsmentioning

confidence: 99%

Measurement of ambient hydroperoxides using an automated HPLC system and various factors which affect variations of their concentrations in Korea

Hong

Kim

Kang

et al. 2008

Environ Monit Assess

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An HPLC system was automated for the measurement of gaseous hydroperoxides in the ambient air. In this system, samples collected using a glass coil without a long sampling tube are injected automatically into HPLC. The analytical system is based on the post-column derivatization, which is a reaction of hydroperoxides with p-hydroxyphenyl acetic acid to produce a fluorescent dimer in the presence of horseradish peroxidase as an enzyme catalyst. The detection limits of hydrogen peroxide (H(2)O(2)) were from 0.018 to 0.042 ppbv. The gaseous hydroperoxides were measured in Gwangju during March, May and October 2002, and in Seoul during June 2002. H(2)O(2) concentrations were remarkably low and almost at the detection limit during a period of the yellow sand (Asian dust). These results might be strongly ascribed to the effect of Asian dust particles for heterogeneous loss of peroxides and partly loss of samples due to the storage of sample and analysis. Methyl hydroperoxide (CH(3)OOH) was identified and quantified only in Seoul. The highest concentrations of H(2)O(2) were 0.24, 2.84, and 0.89 ppbv during March, May, October, respectively in Gwangju, and 5.19 ppbv in Seoul. The concentration of CH(3)OOH was as high as 1.1 ppbv and sometimes its concentration was higher than that of H(2)O(2) in the early morning or in the late night. The variability of CH(3)OOH was lower than that of H(2)O(2). H(2)O(2) showed a positive relationship with O(3) (r = 0.54, P < 0.01 level; two-tailed), solar radiation (r = 0.61, P < 0.01 level; two-tailed), temperature (r = 0.66, P < 0.01 level; two-tailed), and a negative relationship with NO( x ) (r = -0.20, P < 0.05 level; two-tailed), and relative humidity (r = -0.58, P < 0.01 level; two-tailed) in Seoul. Thus, photochemical activity is considered an important factor in gaseous H(2)O(2) and CH(3)OOH distribution.

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The Simultaneous Determination of Bis(hydroxymethyl)-peroxide (BHMP), Hydroxymethylhydroperoxide (HMP), and H2O2 with Titanium(IV). Equilibria Between the Peroxides and the Stabilities of HMP and BHMP at Physiological Conditions.

Cited by 67 publications

References 0 publications

Isoprene NO₃ Oxidation Products from the RO₂ + HO₂ Pathway

Isoprene NO₃ Oxidation Products from the RO₂ + HO₂ Pathway

The kinetics of complex formation between Ti(IV) and hydrogen peroxide

Measurement of ambient hydroperoxides using an automated HPLC system and various factors which affect variations of their concentrations in Korea

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The Simultaneous Determination of Bis(hydroxymethyl)-peroxide (BHMP), Hydroxymethylhydroperoxide (HMP), and H2O2 with Titanium(IV). Equilibria Between the Peroxides and the Stabilities of HMP and BHMP at Physiological Conditions.

Cited by 67 publications

References 0 publications

Isoprene NO3 Oxidation Products from the RO2 + HO2 Pathway

Isoprene NO3 Oxidation Products from the RO2 + HO2 Pathway

The kinetics of complex formation between Ti(IV) and hydrogen peroxide

Measurement of ambient hydroperoxides using an automated HPLC system and various factors which affect variations of their concentrations in Korea

Contact Info

Product

Resources

About

Isoprene NO₃ Oxidation Products from the RO₂ + HO₂ Pathway

Isoprene NO₃ Oxidation Products from the RO₂ + HO₂ Pathway