Decontamination of Dichlorvos by Hydrogen Peroxide

H2O2 aerosol was used to oxidize dichlorvos vapor. 80.7% of dichlorvos, with the initial concentration of 90.9 mg/m3, was decontaminated when the H2O2 concentration kept in the range of 110~130 mg/m3 within 60 min. According to the oxidation products, analyzed by GC-MS, the decontamination reaction mechanism was discussed. Radical chain reaction is the main decontamination mechanism. H2O2 is dissociated to HOO-, which can induce the formation of ·OH. The double bond in dichlorvos molecule is attacked by ·OH to form molecule radical, which is further oxidized to 1,1-dichloro ethoxy dimethyl phosphate, 1,1,1-trichloro-2-hydroxyl-ethyl dimethyl phosphate, dimethyl phosphite, dimethyl phosphate, trimethyl phosphate, methyl phosphate, dichloro acetaldehyde, oxalic acid, CH2Cl2, CHCl3, parts of which are mineralized to phosphoric acid, CO2, H2O and chloridion.

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The high-temperature oxidation of propane

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1959.0079 ◽

1959 ◽

Vol 250 (1263) ◽

pp. 493-513 ◽

Cited By ~ 16

Keyword(s):

Hydrogen Peroxide ◽

Oxidation Products ◽

Methyl Radicals ◽

Secondary Oxidation ◽

Chain Reaction ◽

Radical Chain ◽

Temperature Oxidation ◽

Second Stage ◽

Reaction Proceeds ◽

Homogeneous Decomposition

Above 400 °C propane is oxidized by a two-stage degenerately branching chain reaction. The first 20% of reaction proceeds by an HO 2 /C 3 H 7 radical chain where the main immediate products are propylene and hydrogen peroxide. Pyrolysis of a small fraction of the propyl radicals gives rise to methyl radicals and finally formaldehyde. The further oxidation of formaldehyde by molecular oxygen probably accounts for the observed chain branching although at temperatures above 475 °C homogeneous decomposition of hydrogen peroxide may lead to the initiation of new chains. In the second stage of the reaction the secondary oxidation of propylene becomes important. While propane still in the main reacts to form propylene the subsequent oxidation of the propylene alters both the kinetics and the oxidation products so that the reaction appears overall to proceed by a mechanism similar to that operative at temperatures below 400 °C where the important branching agents are probably higher aldehydes.

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IRRADIATION OF AQUEOUS CHLORAL HYDRATE WITH Sr90–Y90 BETA RAYS

Canadian Journal of Chemistry ◽

10.1139/v59-146 ◽

1959 ◽

Vol 37 (6) ◽

pp. 1022-1028 ◽

Cited By ~ 6

Author(s):

R. F. Platford ◽

J. W. T. Spinks

Keyword(s):

Free Radical ◽

Rate Constants ◽

Chloral Hydrate ◽

Average Lifetime ◽

Chain Reaction ◽

Radical Chain ◽

Acid Yield ◽

Initial Concentration ◽

Free Radical Chain Reaction ◽

Radical Chain Reaction

Air-saturated aqueous chloral hydrate has been irradiated with beta rays and the acid yield as determined by titration has been studied as a function of dose rate, temperature, and initial concentration of the chloral hydrate.The average lifetime of the intermediates has been found, by means of the rotating sector technique, to be about 0.5 second. Propagation and termination rate constants for the reaction have been calculated and an effort has been made to explain the results observed in terms of a free radical chain reaction.

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Catalyst- and Silane- Controlled Enantioselective Hydrofunctionalization of Alkenes by Cobalt-Catalyzed Hydrogen Atom Transfer and Radical-Polar Crossover

10.26434/chemrxiv.9981395 ◽

2020 ◽

Author(s):

Kousuke Ebisawa ◽

Kana Izumi ◽

Yuka Ooka ◽

Hiroaki Kato ◽

Sayori Kanazawa ◽

...

Keyword(s):

Hydrogen Atom ◽

Absolute Configuration ◽

Kinetic Resolution ◽

Hydrogen Atom Transfer ◽

Biologically Active ◽

Atom Transfer ◽

High Concentration ◽

Chain Reaction ◽

Radical Chain ◽

Radical Chain Reaction

Catalytic enantioselective synthesis of tetrahydrofurans, which are found in the structures of many biologically active natural products, via a transition-metal catalyzed-hydrogen atom transfer (TM-HAT) and radical-polar crossover (RPC) mechanism is described herein. Hydroalkoxylation of non-conjugated alkenes proceeded efficiently with excellent enantioselectivity (up to 94% ee) using a suitable chiral cobalt catalyst, <i>N</i>-fluoro-2,4,6-collidinium tetrafluoroborate, and diethylsilane. Surprisingly, absolute configuration of the product was highly dependent on the steric hindrance of the silane. Slow addition of the silane, the dioxygen effect in the solvent, thermal dependency, and DFT calculation results supported the unprecedented scenario of two competing selective mechanisms. For the less-hindered diethylsilane, a high concentration of diffused carbon-centered radicals invoked diastereoenrichment of an alkylcobalt(III) intermediate by a radical chain reaction, which eventually determined the absolute configuration of the product. On the other hand, a more hindered silane resulted in less opportunity for radical chain reaction, instead facilitating enantioselective kinetic resolution during the late-stage nucleophilic displacement of the alkylcobalt(IV) intermediate.

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The reaction of thionitrites with barton esters: a convenient free radical chain reaction for decarboxylative nitrosation

Tetrahedron ◽

10.1016/s0040-4020(98)01164-8 ◽

1999 ◽

Vol 55 (12) ◽

pp. 3573-3584 ◽

Cited By ~ 16

Author(s):

Pierre Girard ◽

Nadine Guillot ◽

William B. Motherwell ◽

Robyn S. Hay-Motherwell ◽

Pierre Potier

Keyword(s):

Free Radical ◽

Chain Reaction ◽

Radical Chain ◽

Free Radical Chain Reaction ◽

Radical Chain Reaction

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ChemInform Abstract: A FREE-RADICAL CHAIN REACTION INVOLVING ELECTRON TRANSFER. THE REPLACEMENT OF THE NITRO GROUP BY HYDROGEN USING TRIALKYLTIN HYDRIDE, A VARIATION OF THE KORNBLUM REACTION

Chemischer Informationsdienst ◽

10.1002/chin.198127133 ◽

1981 ◽

Vol 12 (27) ◽

Author(s):

D. D. TANNER ◽

E. V. BLACKBURN ◽

G. E. DIAZ

Keyword(s):

Electron Transfer ◽

Free Radical ◽

Nitro Group ◽

Chain Reaction ◽

Radical Chain ◽

Kornblum Reaction ◽

Free Radical Chain Reaction ◽

Radical Chain Reaction

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Radical Chain Reaction of Alkene Molecule on H-terminated Si(100)-2×1 Surface

Acta Physico-Chimica Sinica ◽

10.3866/pku.whxb20080102 ◽

2008 ◽

Vol 24 (01) ◽

pp. 8-12

Author(s):

YAN Hui ◽

◽

YUAN Shi-Ling ◽

LIU Cheng-Bu

Keyword(s):

Chain Reaction ◽

Radical Chain ◽

Radical Chain Reaction

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Future Therapeutic Perspectives into the Alzheimer’s Disease Targeting the Oxidative Stress Hypothesis

Molecules ◽

10.3390/molecules24234410 ◽

2019 ◽

Vol 24 (23) ◽

pp. 4410 ◽

Cited By ~ 10

Author(s):

Jéssika P. Teixeira ◽

Alexandre A. de Castro ◽

Flávia V. Soares ◽

Elaine F. F. da Cunha ◽

Teodorico C. Ramalho

Keyword(s):

Oxidative Stress ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neuronal Cell ◽

The Elderly ◽

Oxygen Species ◽

Chain Reaction ◽

Radical Chain ◽

App Metabolism ◽

Radical Chain Reaction

Alzheimer’s disease (AD) is a neurodegenerative disease that is usually accompanied by aging, increasingly being the most common cause of dementia in the elderly. This disorder is characterized by the accumulation of beta amyloid plaques (Aβ) resulting from impaired amyloid precursor protein (APP) metabolism, together with the formation of neurofibrillary tangles and tau protein hyperphosphorylation. The exacerbated production of reactive oxygen species (ROS) triggers the process called oxidative stress, which increases neuronal cell abnormalities, most often followed by apoptosis, leading to cognitive dysfunction and dementia. In this context, the development of new therapies for the AD treatment is necessary. Antioxidants, for instance, are promising species for prevention and treatment because they are capable of disrupting the radical chain reaction, reducing the production of ROS. These species have also proven to be adjunctive to conventional treatments making them more effective. In this sense, several recently published works have focused their attention on oxidative stress and antioxidant species. Therefore, this review seeks to show the most relevant findings of these studies.

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