Kinetic Isotope Effect for Hydrogen Abstraction by•OH Radicals from Normal and Carbon-Deuterated Ethyl Alcohol and Methylamine in Aqueous Solutions†

2003 ◽  
Vol 107 (30) ◽  
pp. 7268-7276 ◽  
Author(s):  
Marija Bonifačić ◽  
David A. Armstrong ◽  
Igor Štefanić ◽  
Klaus-Dieter Asmus
Keyword(s):  
Aqueous Solutions ◽  
Isotope Effect ◽  
Ethyl Alcohol ◽  
Kinetic Isotope Effect ◽  
Hydrogen Abstraction ◽  
Oh Radicals ◽  
Kinetic Isotope

Efficient oxidation of ethers with pyridine N-oxide catalyzed by ruthenium porphyrins

2015 ◽  
Vol 19 (01-03) ◽  
pp. 411-416 ◽  
Author(s):  
Nobuki Kato ◽  
Yu Hamaguchi ◽  
Naoki Umezawa ◽  
Tsunehiko Higuchi
Keyword(s):  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Hydrogen Abstraction ◽  
Oxide System ◽  
Cyclic Ethers ◽  
Rate Determining Step ◽  
Kinetic Isotope ◽  
Oxidized Products

We found that oxidation of cyclic ethers with the Ru porphyrin-heteroaromatic N-oxide system gave lactones or/and ring-opened oxidized products with regioselectivity. A relatively high kinetic isotope effect was observed in the ether oxidation, suggesting that the rate-determining step is the first hydrogen abstraction.

Reactions of trifluoromethyl radicals. V. Hydrogen abstraction from methyl acetate and methyl (2H3)Acetate

1980 ◽  
Vol 33 (7) ◽  
pp. 1437
Author(s):  
NL Arthur ◽  
PJ Newitt
Keyword(s):  
Isotope Effect ◽  
Rate Constants ◽  
Methoxy Group ◽  
Methyl Acetate ◽  
Kinetic Isotope Effect ◽  
Hydrogen Abstraction ◽  
Activation Energies ◽  
Temperature Range ◽  
Kinetic Isotope ◽  
Acetyl Group

Hydrogen abstraction by CF3 radicals from CH3COOCH3 and CD3COOCH3 has been studied in the temperature range 78-242°, and data have been obtained for the reactions: CF3 + CH3COOCH3 → CF3H+[C3H5O2] �������������(3) CF3 + CH3COOCH3 → CF3H+CH2COOCH3������������ (4) CF3 + CD3COOCH3 → CF3D+CD2COOCH3������������ (6) CF3 + CD3COOCH3 → CF3H+CD3COOCH2������������ (7) The corresponding rate constants, based on the value of 1013.36 cm3 mol-1 S-1 for the recombination of CF3 radicals, are given by (k in cm3 mol-1 s-1 and E in J mol-1): logk3 = (11.52�0.05)-(35430�380)/19.145T ���� (3)logk4 = (11.19�0.07)-(34680�550)/19.145T ���� (4)logk6 = (11.34�0.06)-(46490�490)/19.145T ���� (6)logk7 = (11.26�0.05)-(36440�400)/19.145T ���� (7)At 400 K, 59% of abstraction occurs from the acetyl group, and 41 % from the methoxy group. The kinetic isotope effect at 400 K for attack on the acetyl group is 25, due mainly to a difference in activation energies.

Kinetic Isotope Effect for γ-Radiolytic Reduction of Divalent Lead in Aqueous Solutions

1994 ◽  
Vol 4 (4) ◽  
pp. 124-125
Author(s):  
Aleksandr Yu. Garnov ◽  
Sergey I. Nikitenko ◽  
Arkadii A. Lukonin ◽  
Boris G. Ershov
Keyword(s):  
Aqueous Solutions ◽  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Kinetic Isotope ◽  
Radiolytic Reduction

Effect of changing pH upon the kinetic 13C-isotope effect in the decarboxylation of 4-methoxyanthranilic acid

1968 ◽  
Vol 46 (4) ◽  
pp. 563-566 ◽  
Author(s):  
G. E. Dunn ◽  
John Buccini
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Isotope Effect ◽  
Aromatic Ring ◽  
Kinetic Isotope Effect ◽  
13C Isotope ◽  
Kinetic Isotope ◽  
The One

The 13C-carboxyl kinetic isotope effect on decarboxylation of 4-methoxyanthranilic acid has been determined in aqueous solutions of ionic strength 0.50 at 60 °C. The isotope effect, 100(k12/k13 −1), is found to be 4.2% at pH −0.3, 1.4% at pH 1.3, and zero at pH 4.0. This information makes it possible to decide between two mechanisms previously proposed in favor of the one in which both anion and neutral acid are protonated at carbon-1 of the aromatic ring but only the protonated anion decarboxylates.

Reactions of Methyl Radicals. III. Hydrogen Abstraction from Methyl Acetate and Methyl [2H3]Acetate

1979 ◽  
Vol 32 (8) ◽  
pp. 1697 ◽  
Author(s):  
NL Arthur ◽  
PJ Newitt
Keyword(s):  
Isotope Effect ◽  
Rate Constants ◽  
Methoxy Group ◽  
Methyl Acetate ◽  
Kinetic Isotope Effect ◽  
Hydrogen Abstraction ◽  
Methyl Radicals ◽  
Temperature Range ◽  
Kinetic Isotope ◽  
Acetyl Group

A study of hydrogen abstraction by CH3 radicals from CH3COOCH3 in the temperature range 116-224°, and from CD3COOCH3 in the range 117-234°, has yielded data on the reactions: CH3 + CH3COOCH3 → CH4 + [C3H5O2] (4) CH3 + CH3COOCH3 → CH4 + CH2COOCH3 (5) CH3 + CH3COOCH3 → CH4 + CH3COOCH2 (6) CH3 + CD3COOCH3 → CH3D + CD2COOCH3 (7) The corresponding rate constants, based dn the value of 1013.34 cm3 mol-1 s-1 for the recombination of CH3 radicals, are given by (k in cm3 mol-1 s-1 and E in J mol-1): logk4 = (11.56 ± 0.12) - (44430 ± 970)/19.145T (4) logk5 = (11.17 ± 0.22) - (42900 ± 1760)/19.145T (5) logk6 = (11.44 ± 0.16) - (46980 ± 1290)/19.145T (6) logk7 = (11.39 ± 0.04) - (52110 ± 330)/19.145T (7) At 400 K, 64% of abstraction occurs from the acetyl group, and 36% from the methoxy group. The kinetic isotope effect at 400 K for attack on the acetyl group is 9.6; this is mainly due to a difference in activation energies since the quotient of A factors is close to unity.

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