Quasiclassical trajectory study of the F + H2 system. Rate constants, kinetic isotope effects and energy partitioning among reaction products

Rate constants in aqueous solutions are reported for proton and deuteron abstraction by a variety of bases from tricarbomethoxymethane, the propan-2-one-1-sulphonate ion, 2-acetylcyclohexanone and ethyl nitroacetate. The rates of ionization were measured by using bromine or iodine as scavengers to remove the anions, and, for ethyl nitroacetate by direct observation of the rate of appearance of the anion. The kinetic isotope effects vary from k H / k D = 2.5 to k H / k D = 10.3, and confirm the regularities previously found (Bell & Crooks 1965; Bell & Goodall 1966). In particular, the results for the reaction of ethyl nitro-acetate with nine bases show clearly that with increasing basic strength the isotope effect passes through a well-marked maximum. Sterically hindered pyridine bases give rise to abnormally high isotope effects, probably attributable to increased tunnel corrections.

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Quantum Mechanical Enhancement of Rate Constants and Kinetic Isotope Effects for Water-Mediated Proton Transfer in a Model Biological System

The Journal of Physical Chemistry A ◽

10.1021/acs.jpca.6b10337 ◽

2017 ◽

Vol 121 (4) ◽

pp. 819-826 ◽

Cited By ~ 6

Author(s):

James W. Mazzuca ◽

Chase P. Schultz

Keyword(s):

Proton Transfer ◽

Biological System ◽

Rate Constants ◽

Isotope Effects ◽

Kinetic Isotope Effects ◽

Quantum Mechanical ◽

Kinetic Isotope

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The lowest-lying electronic singlet and triplet potential energy surfaces for the HNO–NOH system: Energetics, unimolecular rate constants, tunneling and kinetic isotope effects for the isomerization and dissociation reactions

The Journal of Chemical Physics ◽

10.1063/1.4704895 ◽

2012 ◽

Vol 136 (16) ◽

pp. 164303 ◽

Cited By ~ 25

Author(s):

Uğur Bozkaya ◽

Justin M. Turney ◽

Yukio Yamaguchi ◽

Henry F. Schaefer

Keyword(s):

Potential Energy ◽

Rate Constants ◽

Potential Energy Surfaces ◽

Isotope Effects ◽

Kinetic Isotope Effects ◽

Kinetic Isotope ◽

Energy Surfaces

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Hydrogen abstraction from (2H3)methyl acetate by methyl and trifluoromethyl radicals

Australian Journal of Chemistry ◽

10.1071/ch9810727 ◽

1981 ◽

Vol 34 (4) ◽

pp. 727 ◽

Cited By ~ 2

Author(s):

NL Arthur ◽

PJ Newitt

Keyword(s):

Rate Constants ◽

Methoxy Group ◽

Methyl Acetate ◽

Isotope Effects ◽

Hydrogen Abstraction ◽

Kinetic Isotope Effects ◽

Temperature Range ◽

Kinetic Isotope ◽

Acetyl Group

A study of hydrogen abstraction from CH3COOCD3 by CH3 radicals in the temperature range 113-232�, and by CF3 radicals in the range 83-212�, has yielded data on the reactions: CH3+CH3COOCD3 → CH4+CH2COOCD3 (1)CH3+CH3COOCD3 → CH3D+CH3COOCD2 (2) CF3+CH3COOCD3 → CF3H+CH2COOCD2 (3) CF3+CH3COOCD3 → CF3D+CH3COOCD2 (4) The corresponding rate constants, based on the values 1013.34 and 1013.36 cm3 mol-1 s-1 for the recombination of CH3 and CF3 radicals, respectively, are given by (k in cm3 mol-1 s-1 and E in J mol-1): logk1 = (11.31�0.12)-(43500�1030)/19.145T (1) logk1 = (11.31�0.12)-(53460�640)/19.145t (2) logk3 = (11.12�0.06)=(34260�450)/19.145T � (3) logk4 =(10.93�0.12)-(38650�900)/19.145T (4)These results lead to kinetic isotope effects at 400 K for attack on the acetyl group of 11, for the CH3 reaction, and 24, for the CF3 reaction, thus confirming the values we obtained previously. For attack on the methoxy group, the kinetic isotope effects are 8 and 4, for the CH3 and CF3 reactions, respectively.

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