A comparative application of two-way and three-way analysis to three-dimensional voltammetric dataset for the pKa determination of vanillin

Yazan, Zehra; Erden, Sevcan; Dinç, Erdal

doi:10.1016/j.jelechem.2018.07.047

Cited by 18 publications

(5 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pH values observed in atmospheric water droplets and aqueous aerosol particles were frequently found to be in the range of 3 to 5, , so we investigated the effects of pH on the photooxidation of VL under simulated sunlight irradiation by conducting experiments on the air-saturated solutions of 1 mM NO 2 – and 100 μM VL with the pH adjusted to 3 to 5. As shown in Figure a and Figure S2, the photodegradation of VL (p K a = 7.9) followed pseudo-first order kinetics, and the decay rate was faster under more acidic conditions. For instance, the rate constant is more than a factor of 3 higher at pH = 3 (2.3 × 10 –2 min –1 ) than at pH = 5 (7.1 × 10 –3 min –1 ; Figure S2).…”

Section: Resultsmentioning

confidence: 86%

Nitrite-Mediated Photooxidation of Vanillin in the Atmospheric Aqueous Phase

Pang

Zhang

et al. 2019

Environ. Sci. Technol.

View full text Add to dashboard Cite

Nitrite (NO 2 − ) and its conjugate acid, nitrous acid (HNO 2 ), have long been recognized as a ubiquitous atmospheric pollutant as well as an important photochemical source of hydroxyl radicals (•OH) and reactive nitrogen species (•NO, • NO 2 , •N 2 O 3 , etc.) in both the gas phase and aqueous phase. Although NO 2 − /HNO 2 plays an important role in atmospheric chemistry, our understanding on its role in the chemical evolution of organic components in atmospheric waters is rather incomplete and is still in dispute. In this study, the nitrite-mediated photooxidation of vanillin (VL), a phenolic compound abundant in biomass burning emissions, was investigated under pH conditions relevant for atmospheric waters. The influence of solution pH, dissolved oxygen, and •OH scavengers on the nitrite-mediated photooxidation of VL was discussed in detail. Our study reveals that the molecular composition of the products is dependent on the molar ratio of NO 2 − /VL in the solution and that nitrophenols are the major reaction products. We also found that the light absorbance of the oxidative products increases with increasing pH in the visible region, which can be attributed to the deprotonation of the nitrophenols formed. These results contribute to a better understanding of methoxyphenol photooxidation mediated by nitrite as a source of toxic nitrophenols and climatically important brown carbon in atmospheric waters.

show abstract

Section: Resultsmentioning

confidence: 86%

Nitrite-Mediated Photooxidation of Vanillin in the Atmospheric Aqueous Phase

Pang

Zhang

et al. 2019

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The conditions were appli- cable to the nitration of sesamol (1 o) and 5-hydroxyindan (1 p). Vanillin (1 s), albeit with much lower pK a (7.9) [19] than other substituted phenols (> 9.4), was nitrated in excellent yield. 4-Nitroguaiacol was identified together with 5-nitrovanillin (2 s) in the oxidative products of the reaction of vanillin with nitrite, [20] and the exclusive ortho-nitration observed in this study may be attributed to the controlled interfacial reaction.…”

Section: Resultsmentioning

confidence: 96%

“…Nuclear magnetic resonance (NMR) spectra were recorded on a JEOL ECX-600 spectrometer, operating at 600 MHz at 1 H and 151 MHz for 13 C NMR, or JEOL ECA-500 spectrometer, operating at 500 MHz at 1 H and 125 MHz for 13 C NMR. Tetramethylsilane (TMS) served as the internal standard (δ = 0 ppm) for 1 H NMR, CDCl 3 (δ = 77.0 ppm) or DMSO-d 6 (δ = 39.5 ppm) were used as the internal standard for 13 C NMR, and PhCF 3 (δ = À 63.7 ppm) was used as the internal standard for 19 F NMR, unless otherwise noted. Infrared (IR) spectra were obtained using a SHIMADZU IRSpirit spectrometer.…”

Section: General Remarksmentioning

confidence: 99%

2‐Methoxyethyl Nitrite as a Reagent for Chemoselective On‐Water Nitration

Kitanosono

Hashidoko

Yamashita

et al. 2022

Chemistry An Asian Journal

View full text Add to dashboard Cite

An on-water approach has been developed that allows a nitration of tyrosines and phenols under mild conditions. We envisioned that the assembly of tyrosine/ tyrosyl radical couples with interfacial water molecules would realize a biomimetic stacking hydrogen atom transfer (HAT) transition state to facilitate the electron-transfer process. The optimal organic nitrite, 2-methoxyethyl nitrite, resulted in rapid coupling of the tyrosyl radicals with * NO 2 at the oilwater interface to afford the nitrated phenols. Many characteristics found in our on-water strategy are distinct from other complementary systems that include radical nitration. These enticing roles of water in the reaction process introduce new avenues to explore in the design of synthetic organic chemistry systems.

show abstract

“…That is why there is a growing interest in developing feasible, accurate and alternative methods for determination of pKa values. [1][2] A wide range of experimental techniques, such as potentiometry, [3][4][5] spectrophotometry, [3,[6][7] voltammetry, [8][9] high performance-liquid chromatography (HPLC), [10] capillary electrophoresis (CE) [3,[11][12] are used for pKa determination. The use of all these techniques are based on the measurement of an analytical response as a function of medium pH for determining acid-base dissociation constant of the analyte.…”

Section: Introductionmentioning

confidence: 99%

Two Different Strategies Based on Three‐Way Analysis Models of UV Spectroscopic and Spectrochromatographic Measurements to Quantify the Acidity Constant of Acetylsalicylic Acid

Dinç

Ertekin

2022

ChemistrySelect

Self Cite

View full text Add to dashboard Cite

A comparative study to quantify acid dissociation constant (pKa) of acetylsalicylic acid by applying the parallel factor analysis (PARAFAC) to three‐way data arrays of UV spectroscopic and spectrochromatographic measurements was presented. In data recording and data collection stages, the spectrochromatograms of 20 μg/mL acetylsalicylic acid in different mobile phases having seven different pH levels were recorded, and a cubic data set was created with time x wavelength x pH dimensions. UV spectra of the analyte in the concentration range of 10–30 μg/mL and in seven different pH media were recorded and arranged as a three‐way array with dimensions, wavelength x concentration x pH. To estimate the pKa by two different chemometric strategies, the cubic data sets were decomposed into trilinear components, which allowed to predict the pKa in the pH profiles. In practice, the three‐way analysis‐based UV spectroscopic and spectrochromatographic methods didn't include a titration procedure and had a second‐order advantage over traditional pKa determination methods. As a result, this investigation on the rapid and accurate estimation of the acidity constant of acetylsalicylic acid provided alternative and practical ways to determine the pKa of active pharmaceutical ingredients in the future.

show abstract

A comparative application of two-way and three-way analysis to three-dimensional voltammetric dataset for the pKa determination of vanillin

Cited by 18 publications

References 22 publications

Nitrite-Mediated Photooxidation of Vanillin in the Atmospheric Aqueous Phase

Nitrite-Mediated Photooxidation of Vanillin in the Atmospheric Aqueous Phase

2‐Methoxyethyl Nitrite as a Reagent for Chemoselective On‐Water Nitration

Two Different Strategies Based on Three‐Way Analysis Models of UV Spectroscopic and Spectrochromatographic Measurements to Quantify the Acidity Constant of Acetylsalicylic Acid

Contact Info

Product

Resources

About