Rate constants for reactions of singlet oxygen with phenols and other compounds in water

Scully, Frank E.; Hoigné, Jürg

doi:10.1016/0045-6535(87)90004-x

Cited by 241 publications

(143 citation statements)

References 25 publications

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“…According to currently accepted criteria (28), these observations indicate that the dyesensttized photooxidation occurs largely via a 0,('4,)-mediated process. This is also consistent with a number of reported findings o n the photooxidizability of the ionized form of variously substituted phenols (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17).…”

Section: Resultssupporting

confidence: 81%

“…T y p e I1 (singlet molecular oxygen (O,('A,)) mediated) photooxidation of phenols and, especially, dye-sensitized reactions, have received much attention over the last f e w years in connection with the behaviour role of compounds involved in biological media (1-6) a s well a s the possibility of processing waste water by sunlight irradiation (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). More specifically, the importance of understanding environmental pathways for phenolic chlorinated and nitro derivatives (the main parent compounds employed in industrial syntheses of phenolic pesticides) led us to carry out a variety o f studies (8)(9)(10)(11)(12)(13)(14)(15)17).…”

Section: Introductionmentioning

confidence: 99%

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Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O₂(¹Δ_g)) in alkaline media

Luiz¹,

Gutiérrez²,

Bocco³

et al. 1993

Can. J. Chem.

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The influence of solvent polarity on the dye-sensitized photooxidation (singlet molecular oxygen (O2(1Δg)) mediated) of a series of para-substituted phenolates was studied. Kinetic evidence obtained shows that the overall and the pure chemical interactions, phenolate–O2(1Δg), depend on the solvent polarity in a different way. This is clearly reflected in the efficiency of O2(1Δg) photooxidation of the substrates: surprisingly, the photooxidation quantum yield increases as the overall quenching rate constant decreases. The substrate photooxidation quantum yields obtained ranged from 0.05 to 0.15, the upper limit corresponding to a moderately polar medium (a benzene–methanol mixture) and the lower to an aqueous medium. We conclude that a high solvent polarity favours only the obtainment of the encounter complex (O2(1Δg)–phenolate), whereas the reactive step is affected in much the same way as those processes where charges are neutralized along the reaction pathway. The results obtained are discussed in terms of a partly polar excited state complex between O2(1Δg) and the phenolates. The rate constant for the reactive pathway in both organic and aqueous media is correlated with the Hammet-type substituent constant R−.

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Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O₂(¹Δ_g)) in alkaline media

Luiz¹,

Gutiérrez²,

Bocco³

et al. 1993

Can. J. Chem.

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“…On the other hand, these products were not observed in the presence of TiO2 or H2O2. [9][10][11]19 Therefore, different photolytical conditions could lead to different transformation products.…”

Section: Identification Of Pcp Photodegradation Productsmentioning

confidence: 99%

“…[4][5][6][7][8] A number of studies on the photochemical transformation of PCP and chlorophenols in the presence of titanium dioxide have been reported. [9][10][11] It was already known that PCP was mainly converted into catechol, hydroquinone or trihydroxylated forms through the addition of hydroxyl radical and less-chlorinated phenols through the photolytically reductive dechlorination. [11][12][13] Apparently, the photolytical conversion of PCP into less toxic products such as less-chlorinated phenols may lead to decrease the toxicity of PCP, since the toxicity of chlorinated phenols depends on the number of substituted chlorines.…”

Section: Introductionmentioning

confidence: 99%

Identification of Photolytical Transformation Products of Pentachlorophenol in Water

et al. 2000

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The photodegradation of pentachlorophenol in water was examined with a high-pressure mercury lamp. A number of photodegradation products of pentachlorophenol, such as less-chlorinated phenols through reductive dechlorination, and catechol and trihydroxylated products via the addition of hydroxyl radicals, were observed as major products. Moreover, polychlorinated biphenylethers, hydroxylated polychlorobiphenylethers and polychlorinated dibenzo-p-dioxins as minor products were also formed by dimerization process during the photolysis of pentachlorophenol. These compounds were identified by gas chromatography-mass spectrometry. The degradation rate of PCP in water was measured against the UV-irradiation time. After the irradiation for 15 min, 75% of PCP was converted into a number of products through reductive dechlorination and oxidation. On the basis of the identified products, the photodegradation pathways of PCP under UV irradiation were proposed.

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“…[247] Alternativ wurde für Transformationen in polar, protischen Lösungsmitteln die intramolekulare Assistenz des gebildeten Phenolats B 1 vorgeschlagen (Pfad B). [248,249] Während 3-Hydroxypyridin (pK a 8.7) [255] ein wenig saurer als Salicylsäuremethylester (pK a 9.8) [256] Diese ungewöhnliche Einheit findet sich auch bei den Streptogramin-Antibiotika der Gruppe B (Abbildung 5.1, rechts), [259] ansonsten ist dieses Strukturmotiv sehr selten.…”

Section: Mechanistische üBerlegungenunclassified

Totalsynthese von Nosiheptid

Wojtas

Riedrich

et al. 2016

Angewandte Chemie

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Eine Totalsynthese des bismakrocyclischen Thiopeptidantibiotikums Nosiheptid gelang durch den Aufbau einer voll funktionalisierten linearen Vorstufe und konsekutive Makrocyclisierungen. Schlüsselmerkmale waren eine kritische Makrothiolactonisierung und eine milde Entschützungsstrategie für den 3‐Hydroxypyridin‐Kern. Der Naturstoff war mit isoliertem authentischem Material im Hinblick auf spektroskopische Daten und antimikrobielle Aktivität identisch.

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Rate constants for reactions of singlet oxygen with phenols and other compounds in water

Cited by 241 publications

References 25 publications

Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O₂(¹Δ_g)) in alkaline media

Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O₂(¹Δ_g)) in alkaline media

Identification of Photolytical Transformation Products of Pentachlorophenol in Water

Totalsynthese von Nosiheptid

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Rate constants for reactions of singlet oxygen with phenols and other compounds in water

Cited by 241 publications

References 25 publications

Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O2(1Δg)) in alkaline media

Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O2(1Δg)) in alkaline media

Identification of Photolytical Transformation Products of Pentachlorophenol in Water

Totalsynthese von Nosiheptid

Contact Info

Product

Resources

About

Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O₂(¹Δ_g)) in alkaline media

Solvent effect on the reactivity of monosubstituted phenols towards singlet molecular oxygen (O₂(¹Δ_g)) in alkaline media