Aromatic substitution by free radicals

Nelson, Peter F.

doi:10.1021/ed032p606

Cited by 4 publications

(3 citation statements)

References 17 publications

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“…The situation changes in the presence of a nucleophilic molecule, like p ‐cymene or toluene. Compounds possessing an aromatic ring may undergo free radical aromatic substitution, which finally leads to the fast termination of the radical chain reaction. For p ‐cymene, it was shown that the substitution takes place at the position ortho to the methyl group.…”

Section: Resultsmentioning

confidence: 99%

Antioxidant synergism and antagonism between selected monoterpenes using the 2,2‐diphenyl‐1‐picrylhydrazyl method

Cieśla

Wojtunik-Kulesza

Oniszczuk

et al. 2016

Flavour & Fragrance J

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This research aims to investigate synergistic and antagonistic antioxidant interactions for binary mixtures of common monoterpenes. The activity was determined spectrophotometrically with the use of the DPPH• assay. Significant antioxidant synergism, between two different monoterpenes, was observed for a mixture of inactive p‐cymene and one of the compounds, characterized by moderate antioxidant activity, e.g. (±)‐citronellal, α‐phellandrene or α‐terpinene. It has been proven that the activity of (±)‐citronellal is increased in the presence of hydrocarbons possessing the aromatic nucleophilic ring, which may react with electrophiles. A possible reaction mechanism was proposed for the synergistic antioxidant effect of p‐cymene and (±)‐citronellal. This research opens new perspectives for studying interactions between isoprene derivatives, found in essential oils. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Antioxidant synergism and antagonism between selected monoterpenes using the 2,2‐diphenyl‐1‐picrylhydrazyl method

Cieśla

Wojtunik-Kulesza

Oniszczuk

et al. 2016

Flavour & Fragrance J

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“…Conventionally, Fenton's reagent417, 418 has been in use as a source of hydroxyl radical, that can be used for organic synthesis as well as for degradation of organic pollutants. This reagent produces hydroxyl radical from hydrogen peroxide in the presence of iron, and is widely used for hydroxylation of benzene and its derivatives to phenol and phenolic compounds 419. The reactions can be summarized as: …”

Section: Applications Of Photocatalysismentioning

confidence: 99%

A Review of Photocatalysis using Self‐organized TiO₂ Nanotubes and Other Ordered Oxide Nanostructures

Paramasivam

Jha

Liu

et al. 2012

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652

496

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Photocatalytic approaches, that is the reaction of light-produced charge carriers at a semiconductor surface with their environment, currently attract an extremely wide scientific interest. This is to a large extent due to the high expectations: i) to convert sunlight directly into an energy carrier (H(2)), ii) to stimulate chemical synthetic reactions, or iii) to degrade unwanted environmental pollutants. Since the early reports in 1972, TiO(2) has been the most investigated photocatalytic material by far; this originates from its outstanding electronic properties that allow for a wide range of applications. Not only the material, but also its structure and morphology, can have a considerable influence on the photocatalytic performance of TiO(2). In recent years, particularly 1D (or pseudo 1D) structures such as nanowires and nanotubes have received great attention. The present Review focuses on TiO(2) nanotube arrays (and similar structures) that grow by self-organizing electrochemistry (highly aligned) from a Ti metal substrate. Herein, the growth, properties, and applications of these tubes are discussed, as well as ways and means to modify critical tube properties. Common strategies are addressed to improve the performance of photocatalysts such as doping or band-gap engineering, co-catalyst decoration, junction formation, or applying external bias. Finally, some unique applications of the ordered tube structures in various photocatalytic approaches are outlined.

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“…Therefore, the use of S2O8 2in contaminant treatment applications does not rely on the direct reaction between S2O8 2and contaminants but on the ability of S2O8 2to produce SO4 •and • OH, the process known as S2O8 2activation. The activation of S2O8 2takes place via the following reactions: (Nelson, 1955), reactions with SO4 •proceed mainly via the latter mechanism (Buxton et al, 1988). The byproducts produced from these reactions can be further oxidized by SO4 •and • OH to generate lower molecular-weight compounds that are often less toxic and more bioavailable.…”

Section: Persulfatementioning

confidence: 99%

Factors affecting contaminant transformation by heat-activated persulfate

Zrinyi¹

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Persulfate-based in situ chemical oxidation (ISCO) involves the injection of persulfate (S2O8 2-) into the subsurface to remediate contaminated groundwater and soils. Although S2O8 2does not react with contaminants to an appreciable extent, it can be activated into stronger oxidants (e.g., SO4 • and • OH) by heat, alkaline solutions, dissolved iron and ironcontaining minerals. The objective of the research described in this thesis is to explore the influence of temperature and background solutes on contaminant transformation by heat-and mineral-activated S2O8 2-. Through the transformation of benzoic acid (a model organic compound) and chlorendic acid (a flame retardant), it was discovered that temperature affects not only the rate of contaminant transformation but also the transformation pathway and distribution of byproducts. Solution pH, alkalinity, and chloride also influence the rates of persulfate activation and contaminant degradation.These novel understandings may help improve the design and operation of S2O8 2--based remedial systems.

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Aromatic substitution by free radicals

Abstract: This article summarizes recent investigations upon orientation and reaction rates with respect to homolytic substitution.

Cited by 4 publications

References 17 publications

Antioxidant synergism and antagonism between selected monoterpenes using the 2,2‐diphenyl‐1‐picrylhydrazyl method

Antioxidant synergism and antagonism between selected monoterpenes using the 2,2‐diphenyl‐1‐picrylhydrazyl method

A Review of Photocatalysis using Self‐organized TiO₂ Nanotubes and Other Ordered Oxide Nanostructures

Factors affecting contaminant transformation by heat-activated persulfate

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Aromatic substitution by free radicals

Abstract: This article summarizes recent investigations upon orientation and reaction rates with respect to homolytic substitution.

Cited by 4 publications

References 17 publications

Antioxidant synergism and antagonism between selected monoterpenes using the 2,2‐diphenyl‐1‐picrylhydrazyl method

Antioxidant synergism and antagonism between selected monoterpenes using the 2,2‐diphenyl‐1‐picrylhydrazyl method

A Review of Photocatalysis using Self‐organized TiO2 Nanotubes and Other Ordered Oxide Nanostructures

Factors affecting contaminant transformation by heat-activated persulfate

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Product

Resources

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A Review of Photocatalysis using Self‐organized TiO₂ Nanotubes and Other Ordered Oxide Nanostructures