Deuterium isotope effects on the dipole moment and polarizability of hydrogen chloride and ammonia

1982 ◽  
Vol 86 (5) ◽  
pp. 654-658 ◽  
Author(s):  
Chava Scher ◽  
Baruch Ravid ◽  
E. Amitai Halevi
Keyword(s):  
Dipole Moment ◽  
Hydrogen Chloride ◽  
Isotope Effects ◽  
Deuterium Isotope Effects

Reactions of alicyclic ketones in carbon tetrachloride. I, The kinetics of the chlorination of cyclopentanone and cyclohexanone catalyzed by hydrogen chloride

1986 ◽  
Vol 64 (9) ◽  
pp. 1681-1689 ◽  
Author(s):  
Eize J. Stamhuis ◽  
Henk Maatman ◽  
Henk Stinissen ◽  
Geert E. H. Joosten
Keyword(s):  
Carbon Tetrachloride ◽  
Hydrogen Chloride ◽  
Isotope Effects ◽  
Reaction Rates ◽  
Zero Order ◽  
Rate Determining Step ◽  
Conjugate Acid ◽  
Deuterium Isotope Effects ◽  
Self Association ◽  
Kinetics Of

The kinetics of the direct chlorination of cyclopentanone (cp) and cyclohexanone (ch) in carbon tetrachloride, catalyzed by hydrogen chloride, was studied. The rate of chlorination, measured by flow and stopped-flow techniques, is zero order in chlorine; the order in cp and ch increases from 1 at [cp] and [ch] of 0.01 M concentration to 2 at concentrations of 1 M. This is explained by self-association of the ketones in carbon tetrachloride solutions. The order in hydrogen chloride is 1. Since this compound is one of the products, the reaction is autocatalytic. Deuterium isotope effects and the kinetic data strongly point to a mechanism in which the oxygen-protonated monomeric ketone is α-carbon deprotonated in a rate-determining step. This step, which is catalyzed by the bases cp or ch, respectively, leads to the corresponding enol as intermediate. The enol is then chlorinated very rapidly. In addition to the chloro ketone, very reactive chloride anions are formed. A small fraction of these anions deprotonate α- or α′-carbon atoms of the oxygen-conjugate acid of the monochloro ketone. The remainder are captured by HCl to form energetically more favored Cl--(HCl)n complexes with n = 1, 2, or 3. This explains why, even at low conversions of the ketones, substantial amounts of the various dichloro isomers are formed in addition to monochloro products. A rate expression is derived, which excellently describes the experimentally obtained rates of chlorination of cp and ch over a range of reaction rates of more than three decades.

Mechanism of hydration and isomerisation of 4-ethylidene-2,6-di-tert-butyl-2,5-cyclohexadien-1-one. Kinetics, acid-base catalysis and solvent deuterium isotope effects

1979 ◽  
Vol 44 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Milan Souček
Keyword(s):  
Aqueous Medium ◽  
Rate Equation ◽  
Kinetic Data ◽  
Isotope Effects ◽  
Base Catalysis ◽  
Quinone Methide ◽  
Reaction Products ◽  
Acid Base ◽  
Deuterium Isotope Effects ◽  
Hydroxybenzyl Alcohol

Competitive hydration and isomerisation of the quinone methide I at 25 °C in an aqueous medium in the region of pH 2.4-13.0 was studied spectrophotometrically. The only reaction products in the studied range of pH are 4-hydroxybenzyl alcohol (II) and 4-hydroxystyrene (III). The form of the overall rate equation corresponds to a general acid-base catalysis. The mechanism of both reactions for three markedly separated pH regions is discussed on the basis of kinetic data and solvent deuterium effect.

Hydrogen/Deuterium-Isotope Effects on NMR Chemical Shifts and Symmetry of Homoconjugated Hydrogen-Bonded Ions in Polar Solution

2000 ◽  
Vol 122 (51) ◽  
pp. 12878-12879 ◽  
Author(s):  
Parwin Schah-Mohammedi ◽  
Ilja G. Shenderovich ◽  
Carsten Detering ◽  
Hans-Heinrich Limbach ◽  
Peter M. Tolstoy ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Isotope Effects ◽  
Polar Solution ◽  
Nmr Chemical Shifts ◽  
Hydrogen Deuterium ◽  
Deuterium Isotope Effects ◽  
Hydrogen Bonded
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