Radiation chemistry of ethanol :

Freeman, Gordon R.

doi:10.6028/nbs.nsrds.48

Cited by 42 publications

(12 citation statements)

References 18 publications

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“…For the experiments with terphenyl, pyrene, and biphenyl, in which protonations of the anion radicals were slow, ethanol was purified by distillation from CaH 2 and then from NaBH 4 . The solvent quality was judged from the solvated electron half-life; it was 2.5 and 5.5 μs in commercial and purified ethanol, respectively; the latter compares well with the literature value of 6 μs . Monodeuterated ethanol (EtOD) was distilled from NaBD 4 .…”

Section: Methodsmentioning

confidence: 56%

Rate and Driving Force for Protonation of Aryl Radical Anions in Ethanol

et al. 2007

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Aryl radical anions created in liquid alcohols decay on the microsecond time scale by transfer of protons from the solvent. This paper reports a 4.5 decade range of rate constants for proton transfer from a single weak acid, ethanol, to a series of unsubstituted aryl radical anions, Ar-*. The rate constants correlate with free energy change, DeltaG(o), despite wide variations in the two factors that contribute to DeltaG(o): (a) the reduction potentials of the aryls and (b) the Ar-H* bond strengths in the product radicals. For aryl radical anions containing CH2OH substituents, such as 2,2'-biphenyldimethanol*- which is protonated with a rate constant of 3x10(9) s(-1), the faster rates do not fit well in the free energy correlation, suggesting a change in mechanism.

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Section: Methodsmentioning

confidence: 56%

Rate and Driving Force for Protonation of Aryl Radical Anions in Ethanol

et al. 2007

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“…palustre cormus after the reaction with free carbon-centered α-hydroxyethyl radicals (HERs). The main molecular products of de-aerated ethanol radiolysis are EA (CH 3 CHO) and butanediol-2,3 − …”

Section: Results and Discussionmentioning

confidence: 99%

Radiation Chemical Investigation of Antioxidant Activity of Biologically Important Compounds from Plant Materials

et al. 2020

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Radiation chemical modeling of redox reactions of biologically active compounds from plant materials showed that coumarins possess strong antiradical properties. Data confirming the radioprotective properties of these compounds were obtained. Antioxidant activity has been shown for specific medicinal plant extractsMelilotus officinalis and Ledum palustre cormus. The radiation chemical transformations of coumarins revealed that an unsubstituted coumarin has greater radioprotective activity.

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“…They are formed as a result of the disproportionation and combination reactions of α -hydroxyethyl radicals [15,16] Maiboroda et al [17] found that reactions (1) and (2) occur with approximately equal probabilities. Solvated electron, which is formed in the radiolysis of ethanol, can decrease the apparent yield of acetaldehyde because the rate constant of the reaction of solvated electron with…”

Section: Radiolysis Of Ethanol Solutionsmentioning

confidence: 99%

Effect of flavonols on radiation-induced reactions with the participation of α-hydroxyl-containing organic radicals

Grintsevich

Шадыро

2005

High Energy Chem

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1 Flavonols, which are plant polyphenols, are widely used for the regulation of free-radical oxidation processes in biological systems [1][2][3][4]. The antioxidant activity of flavonols, as well as a number of other flavonoids, is responsible for their useful therapeutic properties. Because of this, it is of considerable interest to study the properties of this class of compounds.Previously [5][6][7][8], it was found that biologically important molecules exposed to γ -radiation and other initiators of free-radical processes can be damaged not only by oxidation but also as a result of fragmentation. In the latter process, the step of degradation of α -hydroxyl-containing radicals plays a key role. It was also found [9, 10] that carbonyl-containing compounds and quinones affect free-radical processes that involve α -hydroxyl-containing carbon-centered organic radicals. As regards flavonoids, only a few publications [11][12][13][14] have been devoted to their reactivity toward carbon-centered radicals.In this paper, we report data that allow us to judge the probabilities and reaction pathways of flavonols and structurally related model compounds with organic radicals formed in the radiolysis of ethanol and aqueous ethylene glycol and 2-methoxyethanol solutions. EXPERIMENTALThe figure summarizes the structural formulas of compounds used in this study. Commercial quercetin (more than 95% purity), rutin (more than 95% purity), morin (more than 95% purity), maltol (more than 98% purity), and kojic acid (more than 98% purity) from Aldrich were used without additional purification. Ethanol (96 vol %) was purified using Wolfen Zeosorb LA zeolite and distilled using a 3-m rectification column. 1 Ethylene glycol and 2-methoxyethanol were purified by double distillation. The purity of the substances was monitored by chromatography.Before dissolving samples, ethanol was sparged with high-purity argon (99.9%) for 50 min. All of the subsequent procedures up to sealing ampules with solutions were performed in an argon atmosphere.Ethylene glycol and 2-methoxyethanol solutions at a concentration of 3 mol/l were prepared with twicedistilled water, fresh solutions being used for each particular set of experiments. Required concentrations of additives in the resulting solutions were obtained by introducing weighed portions of test substances into the solutions. Oxygen was removed by five freezingpumping-thawing cycles. Next, the ampules were sealed under vacuum.The γ -radiation of 137 Cs was used as an initiator of free-radical processes in model systems. Irradiation was performed in sealed ampules (inner diameter, 6 mm; height, 40 mm; sample volume, 0.7 ml). The dose rate was 0.31 ± 0.01 Gy/s; the absorbed dose range 0.2-3.5 kGy was used.All of the data given were obtained by averaging the results of no less than three sets of experiments. The radiation-chemical yields of formation of substances were determined from the dose dependence of the buildup of these substances.The concentrations of acetaldehyde, 2,3-butanediol, and methano...

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Radiation chemistry of ethanol :

Abstract: The yields (G) for products and intermediates formed by irradiation of ethanol, in the solid, liquid and gaseous state, have been compiled and reviewed. Rates of reactions of transient ions and radicals and spectroscopic parameters, including optical and esr spectra, are also included.

Cited by 42 publications

References 18 publications

Rate and Driving Force for Protonation of Aryl Radical Anions in Ethanol

Rate and Driving Force for Protonation of Aryl Radical Anions in Ethanol

Radiation Chemical Investigation of Antioxidant Activity of Biologically Important Compounds from Plant Materials

Effect of flavonols on radiation-induced reactions with the participation of α-hydroxyl-containing organic radicals

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