Aqueous chemistry of inorganic free radicals. VI. Effect of oxygen on the rate of photolysis of hydrogen peroxide in aqueous solutions containing carbon monoxide

1969 ◽  
Vol 73 (4) ◽  
pp. 867-873 ◽  
Author(s):  
F. P. Laming ◽  
George Buxton ◽  
W. K. Wilmarth
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Monoxide ◽  
Free Radicals ◽  
Aqueous Solutions ◽  
Aqueous Chemistry ◽  
Effect Of Oxygen

The gaseous oxidation of aliphatic alcohols. III. n - and iso -propyl alcohols

1960 ◽  
Vol 257 (1290) ◽  
pp. 402-412 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Monoxide ◽  
Free Radicals ◽  
Induction Period ◽  
Isopropyl Alcohol ◽  
Side Reactions ◽  
Chain Mechanism ◽  
Complete Elimination ◽  
Chain Branching ◽  
A Chain

A study of the gaseous oxidation of n -propyl alcohol (1-propanol) at 264°C shows that, after an induction period during which higher aldehydes and hydrogen peroxide are apparently the only products formed, the pressure starts to rise autocatalytically and methanol, formaldehyde and carbon monoxide become detectable. Additions of higher aldehydes reduce the induction period but the amounts required for its complete elimination are considerably greater than those normally present at the end of the induction period. A chain mechanism is proposed which involves initially abstraction of hydrogen from 1-propanol by HO 2 radicals followed by interaction of the resulting hydroxypropyl radicals with oxygen to yield propionaldehyde. Further reactions of this aldehyde are believed to be responsible for chain-branching and for the formation of the various C 1 products. Isopropyl alcohol (2-propanol) is much less readily oxidized than 1-propanol. At 330°C the main oxidation product is acetone which is formed together with hydrogen peroxide in somewhat smaller quantities. Minor products include methanol, acetaldehyde and formaldehyde. The course of the oxidation of 2-propanol is little affected by additions of acetone or formaldehyde but the induction period is markedly reduced by added acetaldehyde. The chain cycle suggested for the initial stages of oxidation involves attack by HO 2 radicals at the tertiary C─H bond of the alcohol followed by reaction of the resulting free radicals with oxygen to give acetone. The intermediate responsible for chain-branching is believed to be acetaldehyde which is produced by side reactions. C 1 compounds are formed partly by oxidation of this aldehyde and partly by further reactions of acetone.

Endothelium-dependent contractions to oxygen-derived free radicals in the canine basilar artery

1993 ◽  
Vol 264 (3) ◽  
pp. H859-H864 ◽  
Author(s):  
Z. S. Katusic ◽  
J. Schugel ◽  
F. Cosentino ◽  
P. M. Vanhoutte
Keyword(s):  
Hydrogen Peroxide ◽  
Free Radicals ◽  
Xanthine Oxidase ◽  
Isometric Tension ◽  
Thromboxane B2 ◽  
Prostaglandin F2 Alpha ◽  
Oxygen Derived Free Radicals ◽  
Basilar Arteries ◽  
Canine Basilar Artery ◽  
Effect Of Oxygen

Experiments were designed to determine the effect of oxygen-derived free radicals in isolated canine basilar arteries. Rings with and without endothelium were suspended for isometric tension recording in modified Krebs-Ringer bicarbonate solution bubbled with 95% O2-5% CO2 (temperature = 37 degrees C; pH = 7.4). A radioimmunoassay technique was used to measure production of prostaglandins and thromboxane B2. Xanthine oxidase (1-9 mU/ml, in the presence of 10(-4) M xanthine) and hydrogen peroxide (10(-6) to 10(-4) M) caused concentration-dependent contractions. The removal of endothelium reversed these contractions into relaxations. Contractions to xanthine oxidase and hydrogen peroxide were inhibited in the presence of superoxide dismutase (150 U/ml), catalase (1,200 U/ml), indomethacin (10(-5) M), and SQ 29548 (10(-6) M) but not in the presence of deferoxamine (10(-4) to 10(-3) M) and dimethyl sulfoxide (10(-4) M). NG-monomethyl-L-arginine (3 x 10(-5) M) augmented the contractions to hydrogen peroxide. Xanthine oxidase stimulated production of 6-ketoprostaglandin F1 alpha, prostaglandin F2 alpha, prostaglandin E2, and thromboxane B2. The stimulatory effect was prevented by the removal of endothelial cells. These studies suggest that xanthine oxidase causes endothelium-dependent contractions mediated by: 1) hydrogen peroxide-induced stimulation of the endothelial metabolism of arachidonic acid via the cyclooxygenase pathway, leading to activation of prostaglandin H2-thromboxane A2 receptors, and 2) inactivation of basal production of nitric oxide by superoxide anions.

The effect of cation concentration on the nitrogen splitting constant of nitroxide free radicals

1990 ◽  
Vol 55 (10) ◽  
pp. 2377-2380
Author(s):  
Hamza A. Hussain
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Bonding ◽  
Free Radicals ◽  
Esr Spectroscopy ◽  
The Other ◽  
Tetraethylammonium Bromide ◽  
Splitting Constant ◽  
The One ◽  
Positively Charged ◽  
Two Equilibria

Nitroxide free radicals prepared from diethylamine, piperidine and pyrrolidine by oxidation with hydrogen peroxide were studied by ESR spectroscopy. The changes in the 14N splitting constant (aN) caused by the addition of KBr or tetraethylammonium bromide were measured in dependence on the concentration of the ions. For diethylamine nitroxide and piperidine nitroxide, the results are discussed in terms of two equilibria: the one, involving the anion, is associated with a gain or loss of hydrogen bonds to the nitroxide oxygen atom, the other is associated with the formation of solvent shared units involving the cation, which results in changes in the hydrogen bonding strenght. The large increase in the aN value in the case of pyrrolidine nitroxide is explained in terms of an interaction from one side of the positively charged N atom; the increase in aN in the case of diethylamine and piperidine nitroxides is explained in terms of interactions with both sides of the positively charged N atom.

Radiation-induced oxidation of 2-propanol by hydrogen peroxide in aqueous solutions

1970 ◽  
Vol 48 (18) ◽  
pp. 2948-2948
Author(s):  
C. E. Burchill ◽  
I. S. Ginns
Keyword(s):  
Hydrogen Peroxide ◽  
Aqueous Solutions ◽  
Radiation Induced

not available

Oxidation-reduction chemistry of hydrogen peroxide in aprotic and aqueous solutions

1979 ◽  
Vol 18 (7) ◽  
pp. 1971-1973 ◽  
Author(s):  
Mark M. Morrison ◽  
Julian L Roberts ◽  
Donald T. Sawyer
Keyword(s):  
Hydrogen Peroxide ◽  
Aqueous Solutions ◽  
Oxidation Reduction

Hydrogen Peroxide Yields in X-Irradiated Aqueous Solutions A Sensitive Method Based on Hydrazide Chemiluminescence

1955 ◽  
Vol 3 (4) ◽  
pp. 379 ◽  
Author(s):  
W. V. Mayneord ◽  
W. Anderson ◽  
H. D. Evans ◽  
D. Rosen
Keyword(s):  
Hydrogen Peroxide ◽  
Aqueous Solutions ◽  
Sensitive Method

Gamma radiolysis of alachlor aqueous solutions in the presence of hydrogen peroxide

2010 ◽  
Vol 184 (1-3) ◽  
pp. 308-312 ◽  
Author(s):  
Dongkyu Choi ◽  
O-Mi Lee ◽  
Seungho Yu ◽  
Seung-Woo Jeong
Keyword(s):  
Hydrogen Peroxide ◽  
Aqueous Solutions ◽  
Gamma Radiolysis
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