โ Scribed by A.J. Kresge; D.P.N. Satchell
No coin nor oath required. For personal study only.
IT has recently been demonstrated that secondary hydrogen isotope effects are absent from aromatic substitution by nitronium ion, mercuric ion, and molecular bromine,l** All evidence bearing on the mechanisms of these three reactions is consistent with a two-step reaction sequence having a single intermediate species for the actual substitution process, 3 Another type of aromatic substitution reaation, however, ie thought to exist: the evidence concerning electrophilic subetitution by hydrogen appears to + Work carried out under the auspices of the U.S. Atomic Energy Commission.
H The secondary isotope effeot of 1.046 for bromination cited in this reference is now open to doubt: the expected large primary isotope effect in side ohain bromination2 Gould well account for all of the observed effect, even if only a relatively emall amount of benzyl bromide were formed,
๐ SIMILAR VOLUMES
The PODSs of the Hs system and its isotopic derivatives are used for computing exact adiabatic barriers we Fmd good agreement with experimentally measured ground and vibrationally excited activation energies. The theoretical results should stimulate further measurements of activation energies of vib
## Abstract Nickel metal in various forms is useful for the catalytic exchange labeling of a wide range of compounds from isotopic water or isotopic hydrogen gas sources. Substantial investigative work has been done on the metal's activities in simple test compounds, providing information useful fo