Kinetics of the early stages of high-energy radiation initiated polymerization

Takács, Erzsébet; Wojnárovits, László; Dajka, Katalin

doi:10.1002/1521-3935(20001101)201:16<2170::aid-macp2170>3.0.co;2-4

Cited by 11 publications

(2 citation statements)

References 23 publications

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“…Furthermore, each datum of a spectrum is an average of 5 measurements for the same reasons. The details of the experimental set-up have been described elsewhere [ 28 , 29 ]. The reactions of e aq − were studied in N 2 -saturated solution containing 0.5 mol·dm −3 tert -butanol, which scavenges • OH according to the reaction: • OH + (CH 3 ) 3 COH → H 2 O + • CH 2 C(CH 3 ) 2 OH, affording a radiation chemical yield of G (e aq − ) = 0.28 μmol·J −1 .…”

Section: Methodsmentioning

confidence: 99%

One-Electron Reduction of Penicillins in Relation to the Oxidative Stress Phenomenon

Szabó

Tóth

Takács

et al. 2015

IJMS

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Certain bactericidal antibiotics target mitochondrial components and, due to the leakage of electrons from the electron transport chain, one-electron reduction might occur that can lead to intermediates passing the electron to suitable acceptors. This study aimed at investigating the one-electron reduction mechanism of selected penicillin derivatives using pulse radiolysis techniques. Penicillins can accommodate the electron on each of their carbonyl carbon. Ketyl radicals are thus produced, which are reducing agents with possibility to interact with suitable biomolecules. A detailed mechanism of the reduction is reported.

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Section: Methodsmentioning

confidence: 99%

One-Electron Reduction of Penicillins in Relation to the Oxidative Stress Phenomenon

Szabó

Tóth

Takács

et al. 2015

IJMS

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“…This method is based on using series of short pulses of fast electrons instead of pulses of laser light. High-energy electrons, being a form of ionizing radiation, lead to formation of monomer radicals, thus initiating polymerization. − No initiator is needed, and the polymerizing system does not need to be transparent.…”

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confidence: 99%

Determination of Propagation Rate Coefficient for the Polymerization of N-Vinylpyrrolidone in Aqueous Solution by Pulsed Electron Polymerization and Size Exclusion Chromatography

et al. 2014

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A new method for determination of a propagation rate coefficient in radical polymerization, pulsed electron polymerization−size exclusion chromatography (PEP−SEC), has been tested on N-vinylpyrrolidone in water and shown to yield results very similar to those obtained by the well-established pulsed laser polymerization−size exclusion chromatography (PLP−SEC). A potential advantage of PEP− SEC is its applicability to studying polymerizations in nontransparent systems and lack of any additives. Series of nanosecond pulses of high-energy electrons from an accelerator generate radicals which initiate polymerization. Further analysis of the samples and data processing are the same as in PLP−SEC. The described technique can be potentially developed into a method complementary and/or comparative to PLP−SEC.

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Hydroxyl radical-induced degradation of fenuron in pulse and gamma radiolysis: kinetics and product analysis

Kovács

Mile

Csay

et al. 2014

Environ Sci Pollut Res

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Radiolytic reactions of phenylureas were studied in detail with fenuron model compound in dilute aqueous solutions using pulse radiolysis for detection of the intermediates, gamma radiolysis with UV-Vis and HPLC-MS techniques for analysis of the final products. The kinetics of oxidation was followed by COD, TOC and toxicity measurements. During radiolysis of aerated solutions hydroxyl radical ((•)OH), eaq (-), H(•) and O2 (•-)/HO2 (•) reactive intermediates are produced, the degradation of solute takes place practically entirely through (•)OH reactions. Therefore, the product distribution is similar to the distributions reported in other advanced oxidation processes with (•)OH as main reactant. (•)OH mainly reacts with the aromatic ring, forming cyclohexadienyl radical as an intermediate. This radical in pulse radiolysis has a wide absorption band in the 310-390 nm wavelength range with a maximum at 350 nm. Cyclohexadienyl radical reacts with dissolved O2 with a rate coefficient of ∼ 4 × 10(8) mol(-1) dm(3) s(-1) forming peroxy radical. The latter may eliminate HO2 (•) giving phenols or undergoes fragmentation. The one-electron oxidant (•)OH on average induces more than two-electron oxidations. The toxicity first increases with absorbed dose, then decreases. This increase is partly due to phenols formed during the first degradation period.

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Kinetics of the early stages of high-energy radiation initiated polymerization

Cited by 11 publications

References 23 publications

One-Electron Reduction of Penicillins in Relation to the Oxidative Stress Phenomenon

One-Electron Reduction of Penicillins in Relation to the Oxidative Stress Phenomenon

Determination of Propagation Rate Coefficient for the Polymerization of N-Vinylpyrrolidone in Aqueous Solution by Pulsed Electron Polymerization and Size Exclusion Chromatography

Hydroxyl radical-induced degradation of fenuron in pulse and gamma radiolysis: kinetics and product analysis

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