Formation of Hydrogen Peroxide by Ultrasonic Waves: Free Radicals

Weissler, Alfred

doi:10.1021/ja01514a015

Cited by 166 publications

(93 citation statements)

References 9 publications

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“…2, in the presence of the various gases follows the order 0 2 > air > Ar > N2 in agreement with previously reported results (13,14). The mechanism whereby Hz02 is produced sonolytically has been the subject of some controversy (9,17). The use of hydroxyl radical scavengers to study the diminution of H202 Can.…”

Section: Hydrogen Peroxidesupporting

confidence: 89%

“…In aqueous solution there is evidence (8)(9)(10)(11)) that the lifetime of chemically active radicals produced by sonolysis is larger than the lifetime of the cavitation bubble and so these chemically active species which are formed in the vapour phase of the cavity (the temperature of a hot gas bubble will be greater than 2000 K) migrate and are available to trigger chemical reactions. It has also been shown (1,(12)(13)(14) that the presence of certain gases can alter the secondary reaction of these radicals.…”

Section: Introductionmentioning

confidence: 99%

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The effect of ultrasound on water in the presence of dissolved gases

Mead¹,

Sutherland²,

Verrall³

1976

Can. J. Chem.

149

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Sonolysis of water at 447 kHz causes a decrease in the pH. The products formed depend to some extent on the nature of the dissolved gases; products observed are hydrogen peroxide, nitrous and nitric acid. The yield of hydrogen peroxide follows the order O2 > air > Ar > N2. In the case of total acid (nitrous and nitric) the yield follows the order air >N2 > Ar > O2. Nitrogen fixation occurs in the presence of Ar and O2 because of the presence of small amounts of N2 either as an impurity in the dissolved gases, or as residual air in the incompletely degassed water.An attempt was made by using the Fricke dosimeter to obtain information on the relative chemical activity of cavitation.

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Section: Hydrogen Peroxidesupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

The effect of ultrasound on water in the presence of dissolved gases

Mead¹,

Sutherland²,

Verrall³

1976

Can. J. Chem.

149

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“…Secondary implications are brought from the physicochemical nature of the pollutant. Volatile compounds can scavenge the radicals formed inside the cavitating bubble [118], avoiding their release into the solution or their recombination, a situation which could not occur with non-volatile compounds [ 119 ]. Heinglein et al have determined from radiolysis and ultrasound experiments that the ability of a wide range of known scavengers to decrease H 2 O 2 yields depends only upon their hydrophobic character [120].…”

Section: General Statementsmentioning

confidence: 99%

Sonochemical Treatment of Water Polluted by Chlorinated Organocompounds. A Review

González-Garcı́a

Sáez

Tudela

et al. 2010

Water

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As one of several types of pollutants in water, chlorinated compounds have been routinely subjected to sonochemical analysis to check the environmental applications of this technology. In this review, an extensive study of the influence of the initial concentration, ultrasonic intensity and frequency on the kinetics, degradation efficiency and mechanism has been analyzed. The sonochemical degradation follows a radical mechanism which yields a very wide range of chlorinated compounds in very low concentrations. Special attention has been paid to the mass balance comparing the results from several analytical techniques. As a conclusion, sonochemical degradation alone is not an efficient treatment to reduce the organic pollutant level in waste water.

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“…Esses radicais foram detectados por ressonância de spin eletrônico (ESR) e pela identificação dos adutos: (H-DMPO), (OH-DMPO), (H-PYBN), (OH-PYBN), (H-POBN) e (OH-POBN) 22,23 . Soluções aquosas de acrilamida, ou ácido fórmico, ou aliltiouréia, saturadas com oxigênio ou argônio, quando irradiadas com ondas ultra-sônicas resultam na formação de radical • OH que é um intermediário na produção sonoquímica de peróxido de hidrogênio 21 . A reação de polimerização de acrilonitrila em meio aquoso induzida por ultra-som 17 envolve inicialmente a formação de radicais hidrogênio e hidroxílico, equação 13.…”

Section: Sonóliseunclassified

O efeito do ultra-som em reações químicas

Martines¹,

Davolos²,

Júnior³

2000

Quím. Nova

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Recebido em 2/2/99; aceito em 16/6/99 THE ULTRASOUND EFFECT ON CHEMISTRY REACTIONS. Unusual chemical phenomenon associated with ultrasound is on account of cavitation effect. The ultrasound increase the rate and yield of chemical reaction on account of its ability to emulsify liquids. When the ultrasound is used in metallic catalyst reaction the activity of catalyst is increased because the ultrasound clean the surface of catalyst. Sonogels have a fine porosity and large specific surface improving different properties. This paper deals with ultrasound phenomenon and gives some examples of reactions and properties where this radiation takes an important role.

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Formation of Hydrogen Peroxide by Ultrasonic Waves: Free Radicals

Cited by 166 publications

References 9 publications

The effect of ultrasound on water in the presence of dissolved gases

The effect of ultrasound on water in the presence of dissolved gases

Sonochemical Treatment of Water Polluted by Chlorinated Organocompounds. A Review

O efeito do ultra-som em reações químicas

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