The reaction between 2,2-di(4-nitrophenyl)1,1,1-trifluoroethane and tert-butoxide ion in tert-butyl alcohol solvent

The reaction between 2,2-di(4-nitrophenyl) 1,1,1-trifluoroethane and excess sodium tert-butoxide in tert-butyl alcohol takes place rapidly to yield first the olefin, by elimination of HF. This is followed by a slower addition of tert-butoxide to the olefin, which upon reaction with the solvent gives the tert-butyl ether as the final product. The blue anions involved in each of these reactions are observed.Rate constants, the primary deuterium kinetic isotope effects, and the activation parameters have been measured for the appearance of the initial blue colour and also for the formation of the olefin. It is concluded that the reaction proceeds by a reversible ElcB mechanism.

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Secondary α-deuterium kinetic isotope effects for the E2 reaction of the 2-phenylethyl halides with tert-butoxide ion in tert-butyl alcohol

Canadian Journal of Chemistry ◽

10.1139/v85-017 ◽

1985 ◽

Vol 63 (1) ◽

pp. 100-102 ◽

Cited By ~ 1

Author(s):

Peter James Smith ◽

Kanchugarakoppal S. Rangappa ◽

Kenneth Charles Westaway

Keyword(s):

Isotope Effects ◽

Kinetic Isotope Effects ◽

Order Rate Constant ◽

Butyl Alcohol ◽

Tert Butyl ◽

Kinetic Isotope ◽

Tert Butyl Alcohol ◽

Elimination Reactions ◽

Leaving Groups ◽

High Base

Secondary α-deuterium kinetic isotope effects have been determined for the elimination reactions of 2-phenylethyl halides with tert-butoxide in tert-butyl alcohol at 40 °C in the presence and absence of the crown ether 18C6. The second-order rate constant k2 and the normal (kH/kD)α effect remained constant when the tert-butoxide concentration was varied for reaction of the iodo and bromo compounds. However, both the magnitude of k2 and the secondary α-deuterium isotope effect were significantly dependent on [t-BuO−] when chlorine and fluorine are the leaving groups. It is noteworthy that (kH/kD)α is inverse for the reaction of both the chloro and fluoro compounds at "low" base concentrations and normal at "high" base concentrations. These results are discussed in terms of both syn- and anti-elimination pathways promoted by various associated and dissociated base species. It is suggested that the (kH/kD)α effect may be useful as a criterion for determining the stereochemistry of E2 elimination reactions.

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Using secondary alpha deuterium kinetic isotope effects to determine the stereochemistry of an E2 reaction; the stereochemistry of the E2 reaction of 1-chloro-2-phenylethane with potassium tert-butoxide in tert-butyl alcohol

Canadian Journal of Chemistry ◽

10.1139/v01-086 ◽

2001 ◽

Vol 79 (7) ◽

pp. 1145-1152 ◽

Cited By ~ 2

Author(s):

Peter James Smith ◽

David AJ Crowe ◽

Kenneth Charles Westaway

Keyword(s):

Transition State ◽

Isotope Effects ◽

Kinetic Isotope Effects ◽

Butyl Alcohol ◽

State Structure ◽

Transition State Structure ◽

Isotopic Labelling ◽

Tert Butyl ◽

Kinetic Isotope ◽

Tert Butyl Alcohol

Isotopic labelling studies have shown that the E2 reaction of 1-chloro-2-phenylethane with potassium tert-butoxide in tert-butyl alcohol occurs via an anti-periplanar stereochemistry. This demonstrates that the different secondary alpha deuterium kinetic isotope effects found for the high and low base concentrations and in the presence of 18-crown-6 ether are because of changes in transition state structure that occur when the form of the reacting base changes rather than to a change in the stereochemistry of the reaction.Key words: E2 reaction, stereochemistry, secondary alpha deuterium kinetic isotope effects, transition state.

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Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19931001 ◽

1993 ◽

Vol 58 (5) ◽

pp. 1001-1006 ◽

Cited By ~ 1

Author(s):

Oľga Vollárová ◽

Ján Benko

Keyword(s):

Transfer Functions ◽

Activation Parameters ◽

Butyl Alcohol ◽

Oxidation Of Co ◽

Kinetics Of Oxidation ◽

Tert Butyl ◽

Tert Butyl Alcohol ◽

Alcohol Mixtures ◽

Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

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