Mechanisms of elimination reactions. Part III. Rate coefficients for elimination from substituted 2-phenylethyl arenesulphonates with potassium in t-butyl alcohol

1971 ◽  
pp. 498 ◽  
Author(s):  
J. Banger ◽  
Anthony F. Cockerill ◽  
G. L. O. Davies
Keyword(s):  
Butyl Alcohol ◽  
Rate Coefficients ◽  
Elimination Reactions

THE TRANSMISSION OF POLAR EFFECTS: PART II. THE KINETICS OF ESTERIFICATION WITH DIAZODIPHENYLMETHANE AND THE IONIZATION OF 3-SUBSTITUTED ACRYLIC ACIDS

1965 ◽  
Vol 43 (12) ◽  
pp. 3354-3363 ◽  
Author(s):  
Keith Bowden
Keyword(s):  
Butyl Alcohol ◽  
Polar Effect ◽  
Rate Coefficients ◽  
Strengthening Effect ◽  
Benzoic Acids ◽  
Linear Free Energy ◽  
Substituted Benzoic Acids ◽  
Energy Relations ◽  
Acrylic Acids ◽  
Kinetics Of

The rate coefficients for the reaction with diazodiphenylmethane in ethanol, t-butyl alcohol, and ethyl acetate at 30° and the pKa values in water at 25° of fourteen 3-substituted acrylic acids have been determined. The effect of substitution is assessed by use of linear free energy relations. A definite incremental acid-strengthening effect solely due to cis-substitution is confirmed. This is not a "bulk" steric effect and is due solely to the orientation of substitution. The polar effect of a substituent is found to be approximately the same from the cis- or trans-position. An attempt is made to test the suggested mechanisms for the transmission of the polar effect. In the reactions studied the transmission of the polar effect in 3-substituted acrylic acid and ortho-substituted benzoic acids is approximately twice that of the meta- or para-substituted benzoic acids. This appears to be reasonably accommodated by a significant field effect.

Some elimination reactions of hydroxy tosylates in the bornane series

1972 ◽  
Vol 25 (2) ◽  
pp. 361 ◽  
Author(s):  
RFM Cole ◽  
JM Coxon ◽  
MP Hartshorn
Keyword(s):  
Butyl Alcohol ◽  
Elimination Reactions

The reaction of cis-bornane-2,3-diol monotosylates with potassium t-butoxide in t-butyl alcohol gives exclusively the corresponding born-2-ene epoxide; trans-bornane-2,3-diol monotosylates give a ketone in addition to the epoxide.

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

1985 ◽  
Vol 63 (1) ◽  
pp. 100-102 ◽  
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.

Isotope effect studies on elimination reactions. VII. The stereochemistry of elimination from 2-phenylethylammonium ions

1970 ◽  
Vol 48 (1) ◽  
pp. 133-137 ◽  
Author(s):  
A. N. Bourns ◽  
A. C. Frosst
Keyword(s):  
Magnetic Resonance ◽  
Isotope Effect ◽  
Proton Magnetic Resonance ◽  
Spectroscopic Analysis ◽  
Butyl Alcohol ◽  
Magnetic Resonance Spectroscopic Analysis ◽  
Solvent Systems ◽  
Elimination Reactions

The stereochemistry of the base-promoted elimination reactions of 2-phenylethyltrimethylammonium and 2-phenylethyldimethylanilinium ions has been investigated using both ethoxide ion in ethanol and t-butoxide in t-butyl alcohol as base-solvent systems. The proton magnetic resonance spectroscopic analysis of the deuterated styrene products formed from the reactions of the threo-2-phenylethylammonium-1,2-d2 ions established that elimination proceeds more than 95% by an anti process.

The transmission of polar effects. Part X. The esterification with diazodiphenyl-methane and the ionization of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids

1969 ◽  
Vol 47 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Keith Bowden ◽  
D. C. Parkin
Keyword(s):  
Free Energy ◽  
Ethyl Acetate ◽  
Field Effect ◽  
Isopropyl Alcohol ◽  
Substituent Effects ◽  
Butyl Alcohol ◽  
Rate Coefficients ◽  
Linear Free Energy ◽  
Energy Relations ◽  
Substituted 1

The rate coefficients for the reaction with diazodiphenylmethane in methanol, ethanol, isopropyl alcohol, t-butyl alcohol, 2-methoxyethanol, 2-n-butoxyethanol, and ethyl acetate at 30° and the pKa values in 80% 2-n-butoxyethanol–water of a series of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids have been determined. The effect of substitution has been analyzed by linear free energy relations. The variation in the susceptibilities of the systems to polar substituent effects with the medium are examined. The occurrence of reversed dipolar substituent effects in the reactions of the 1,8-naphthoic acids is detected. The implications of the results for the inductive and field effect models for the transmission of polar effects are discussed.

The transmission of polar effects. Part V. The kinetics of esterification with diazodiphenylmethane and the ionization of substituted acetic and propionic acids in several solvents

1968 ◽  
Vol 46 (18) ◽  
pp. 2929-2940 ◽  
Author(s):  
Keith Bowden ◽  
M. Hardy ◽  
D. C. Parkin
Keyword(s):  
Isopropyl Alcohol ◽  
Butyl Alcohol ◽  
Rate Coefficients ◽  
Esterification Reaction ◽  
Linear Free Energy ◽  
Ionization Reaction ◽  
Reaction Constants ◽  
Polar Substituents ◽  
Energy Relations ◽  
Kinetics Of

The rate coefficients for the reaction with diazodiphenylmethane in methanol, ethanol, isopropyl alcohol,t-butyl alcohol, 2-methoxyethanol, 2-n-butoxyethanol, dimethyl sulfoxide, ethyl acetate, and toluene at 30° and the pKa values in water, 50% ethanol–water, and 80% 2-methoxyethanol–water of 18 substituted acetic and propionic acids have been determined. A further 14 acids have been studied to a more limited extent. The effect of substitution has been estimated by linear free energy relations. The reaction constants for the ionization reaction are almost independent of the medium. This is interpreted as being due to the field effect of the proximate polar substituents passing through the molecular cavity almost alone. The occurrence of steric inhibition of solvation causing acid weakening for bulky multi-substitution is confirmed. The reaction constants for the esterification reaction are affected by the solvent. This is attributed to dependence on solvation of the transition state.

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