Dynamics of reaction of [meso-tetrakis(2,6-dimethyl-3-sulfonatophenyl)porphinato]-iron(III) hydrate with various alkyl hydroperoxides in aqueous solution. 4. Comparison of kinetic parameters and D2O solvent isotope effects

1991 ◽  
Vol 113 (16) ◽  
pp. 6090-6094 ◽  
Author(s):  
Enona Gopinath ◽  
Thomas C. Bruice
Keyword(s):  
Aqueous Solution ◽  
Kinetic Parameters ◽  
Isotope Effects ◽  
Alkyl Hydroperoxides ◽  
Solvent Isotope ◽  
Solvent Isotope Effects

Ketonization of the unusually acidic elongated enol generated by flash photolytic decarboxylation of p-formylphenylacetic acid in aqueous solution

2008 ◽  
Vol 86 (2) ◽  
pp. 101-104 ◽  
Author(s):  
Yvonne Chiang ◽  
Kirill Kolmakov ◽  
A Jerry Kresge
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Sodium Hydroxide ◽  
Perchloric Acid ◽  
Flash Photolysis ◽  
Isotope Effects ◽  
Solvent Isotope ◽  
Solvent Isotope Effects

Rates of photolysis of p-formylphenylacetic acid were measured flash photoytically in perchloric acid and sodium hydroxide solutions, and also in acetic acid, biphosphate ion, and tris-(hydroxymethyl)methaneammonium ion buffers, using H2O and D2O as solvents. The results provide rate profiles and solvent isotope effects, which indicate that photolysis occurs through an elongated enol intermediate. This enol is unusually strongly acidic, by some two to three pQa units, when compared with simple non-elongated enols.Key words: flash photolysis, elongated enols, rate profiles, solvent isotope effects.

Generation of 6-methylene-2,4-cyclohexadienylidene ketene by flash photolysis of benzocyclobutenone in aqueous solution and study of the reactions of this ketene in that medium

2003 ◽  
Vol 81 (6) ◽  
pp. 607-611 ◽  
Author(s):  
Y Chiang ◽  
A J Kresge ◽  
H -Q Zhan
Keyword(s):  
Aqueous Solution ◽  
Ring Opening ◽  
Flash Photolysis ◽  
Isotope Effects ◽  
Buffer Solutions ◽  
Product Identification ◽  
Rate Profile ◽  
Solvent Isotope ◽  
Rates Of Decay ◽  
Solvent Isotope Effects

Flash photolysis of benzocyclobutenone in aqueous solution produced a transient species with a microsecond lifetime whose rates of decay were measured in perchloric acid, sodium hydroxide, and buffer solutions over the acidity range [H+] 1 × 10–13 – 100 M. This produced a rate profile, isotope effects, and buffer behaviour typical of ketene reactions, and that, together with product identification, served to identify this transient as 6-methylene-2,4-cyclohexadienylidene ketene, formed by electrocyclic opening of the four-membered ring of benzocyclobutenone. Comparison of rates of reaction of this ketene with those of its saturated analog, pentamethyleneketene, produced some expected as well as some unexpected results. Key words: cyclobutenone chemistry, electrocyclic ring opening, ketene hydration, rate profile, solvent isotope effects.

Photoredox chemistry of nitrobenzyl alcohols in aqueous solution. Acid and base catalysis of reaction

1986 ◽  
Vol 64 (10) ◽  
pp. 2076-2086 ◽  
Author(s):  
Peter Wan ◽  
Keith Yates
Keyword(s):  
Aqueous Solution ◽  
Isotope Effects ◽  
Base Catalysis ◽  
Quantum Yields ◽  
Hydronium Ion ◽  
Acid And Base ◽  
New Type ◽  
Solvent Isotope ◽  
Catalytic Effects ◽  
Solvent Isotope Effects

The photochemistry of several m- and p-nitrobenzyl alcohols (1–5) has been studied in aqueous solution. These compounds react via an intramolecular photoredox pathway to give reduced and oxidized moieties of the substituent groups. The reaction is an example of a new type of photoreaction of nitro-substituted aromatic derivatives that is not observed in organic solvents, the presence of water being essential. This effect is exemplified by measuring the quantum efficiency as a function of mol% water in aqueous acetonitrile, methanol, and formamide: the reaction efficiency decreases rapidly as water is depleted in the mixture. Catalytic effects due to the hydronium and hydroxide ions were studied: the para derivatives exhibited hydroxide ion catalysis; the meta derivatives exhibited hydronium ion catalysis. Quantum yields, solvent isotope effects, and α-deuterium isotope effects are reported for the parent derivatives.

Solvent isotope effects on the solubility of argon and pair interactions in aqueous solution of hexamethylenetetramine

2000 ◽  
Vol 49 (8) ◽  
pp. 1383-1388 ◽  
Author(s):  
V. K. Abrosimov ◽  
E. V. Ivanov ◽  
L. S. Efremova ◽  
Yu. P. Pankratov
Keyword(s):  
Aqueous Solution ◽  
Isotope Effects ◽  
Solvent Isotope ◽  
Solvent Isotope Effects ◽  
Pair Interactions

Kinetic deuterium isotope effects and kinetic solvent isotope effects for the solvolyses in water and in water + acetonitrile mixtures related to a series of substituted benzyl nitrates

1980 ◽  
Vol 58 (20) ◽  
pp. 2142-2145 ◽  
Author(s):  
Mohammed Ahsan ◽  
Ross Elmore Robertson ◽  
Michael Jesse Blandamer ◽  
John Marshall William Scott
Keyword(s):  
Aqueous Solution ◽  
Benzene Ring ◽  
Isotope Effect ◽  
Isotope Effects ◽  
Bond Breaking ◽  
Relative Importance ◽  
Stage Process ◽  
Deuterium Isotope Effects ◽  
Solvent Isotope ◽  
Solvent Isotope Effects

In aqueous solution, the α-deuterium isotope effects in the solvolyses of benzyl nitrates derivatives depend on the nature of the substituent in the benzene ring. In addition, the isotope effect for some derivatives depends on mole fraction of added acetonitrile while for others the isotope effect is insensitive to solvent composition. However, the kinetic solvent isotope effects for para-methyl and meta-trifluoromethyl derivatives remain unchanged when acetonitrile is added. These observations are accounted for in terms of a model which describes the solvolytic reaction as a two-stage process and contrasts the relative importance of bond-making and bond-breaking.

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