An experimental and theoretical investigation of orientational dependence of H–F couplings in fluoro-olefins

Abraham, Raymond J.; Ellison, Stephen L. R.; Barfield, Michael; Thomas, W. A.

doi:10.1039/p29870000977

Cited by 39 publications

(68 citation statements)

References 2 publications

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“…Thus the equilibrium constant for deprotonation of the tertiary carbocation to give the alkene is Ka = 5.6 x 10" M, or A G O = -16.0 kcal/mol. Abraham (23) gives -16.5 kcal/mol for the same process, in excellent agreement.…”

Section: Thermodynamics Of Ion Triplet Formationsupporting

confidence: 63%

“…Intrinsic barrier for S N l solvolysis Abraham gives a value for the free energy of activation as 24.7 kcal/mol (23,29,30). From this value and the equilibrium free energy change for ionization we can derive the intrinsic barrier as 12.66 kcal/mol in terms of the quadratic model, or 12.39 in terms of the quartic model.…”

Section: Thermodynamics Of Ion Triplet Formationmentioning

confidence: 99%

“…For the simple solvolysis of tBuBr, the free energy of ionization is reasonably well defined, as shown by the agreement of estimated (23) and quasi-experimental values (24,25), and the rate is known (23,29,30) so the intrinsic barrier should also be reasonably well defined, and the uncertainty should be 0 . 8~~~0 .…”

Section: Thermodynamics Of Ion Triplet Formationmentioning

confidence: 99%

“…jCalculated after ref. 23. kEstimated by taking advantage of Abraham's finding (64) that for non-polar molecules free energies of transfer from water to alcohol depend only on molecular volume; since isopropyl bromide has a molar volume (94 mL/mol, calculated from data in ref.…”

Section: Equilibria For C-h Ionizationmentioning

confidence: 99%

“…For the ionization of tert-butyl bromide to the ion pair in ethanol, Abraham change (by a careful estimation procedure) as 20.1 kcal/mol (23).…”

Section: Thermodynamics Of Ion Triplet Formationmentioning

confidence: 99%

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Concertedness and E2 elimination reactions: prediction of transition state position and reaction rates using two-dimensional reaction surfaces based on quadratic and quartic approximations

Guthrie¹

1990

Can. J. Chem.

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This paper is dedicated to Professor Ross Stewart on the occasion of his 65th birthday J. PETER GUTHRIE. Can. J. Chem. 68, 1643 (1990). An analytical expression for the two-dimensional reaction surface appropriate for discussing a concerted reaction has been derived for the quartic approximation to a reaction coordinate, and shown to be consistent with Marcus theory. By analysis of literature data for SN1 solvolyses and carbanion formation we have been able to reproduce the qualitative behavior of eliminations involving tBuBr, iPrBr, and EtBr in EtOH/EtO-, and to predict the rates of these reactions within the uncertainties of the input data. IntroductionWe have recently reported an equation for the energy surface for the situation where two reaction progress variables are required to describe a reaction ( 1 ) . The equation, which was a generalization of the inverted parabola model for the reaction coordinate of a simple reaction, was shown to be consistent with Marcus theory (2-4) for the edge reactions. It provides a basis for predicting when a reaction will be concerted and when it will be stepwise in terms of the thermodynamics and intrinsic barriers of the edge reactions. A logical consequence of the simple theory used is that the intrinsic barriers are the same for each pair of parallel edge reactions.There has been considerable interest in the use of various energy surfaces to analyze concerted reactions ( 1 , 5-18). We wish now to report that, using information from the literature, it is possible to predict which of a set of simple P-elimination reactions are concerted, and to make semiquantitative predictions of the rate constants, with no adjustable parameters.We ( 8 ) and others (19,20) have discussed the advantages of a quartic equation as an approximation to a reaction coordinate diagram, since it has the correct shape at the extrema. We have now devised an analogous equation with two reaction coordinate dimensions, which provides the simplest generalized surface in the quartic approximation with the correct behavior for the edge reactions, and which satisfies Marcus theory for all sections through it.

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Section: Thermodynamics Of Ion Triplet Formationsupporting

confidence: 63%

Section: Thermodynamics Of Ion Triplet Formationmentioning

confidence: 99%

Section: Thermodynamics Of Ion Triplet Formationmentioning

confidence: 99%

Section: Equilibria For C-h Ionizationmentioning

confidence: 99%

“…For the ionization of tert-butyl bromide to the ion pair in ethanol, Abraham change (by a careful estimation procedure) as 20.1 kcal/mol (23).…”

Section: Thermodynamics Of Ion Triplet Formationmentioning

confidence: 99%

See 3 more Smart Citations

Concertedness and E2 elimination reactions: prediction of transition state position and reaction rates using two-dimensional reaction surfaces based on quadratic and quartic approximations

Guthrie¹

1990

Can. J. Chem.

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Stereoselective Palladium‐Catalyzed Four‐Component Cascade Synthesis of Pyrrolidinyl‐, Pyrazolidinyl‐, and Isoxazolidinyl Isoquinolines

et al. 2005

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Study of sorption/desorption of water and organic vapors on poly(ethylene maleate)‐based sensor‐coating materials using an automated gravimetric analyzer

Dubey¹,

Kuthe²,

Saxena³

et al. 2003

J of Applied Polymer Sci

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Hydrophobic comonomers bisphenol-A and hexafluorobisphenol-A were incorporated as diol components in the sensor-coating material poly(ethylene maleate) (PEM), resulting in modified polymers, HCPEM and HFPEM, respectively. To assess the suitability of these polymers as sensor interfaces, the sorption/desorption isotherms and kinetics of water and a range of volatile organic vapors were obtained over the entire relative pressure range of 0.1 to 1.0, using an automated intelligent gravimetric sorption analyzer. The extent and rate of sorption of organic vapors were higher in the modified polymers compared to those of the parent polymer. Sorption hysteresis was observed at high relative pressures, especially with water and other hydrogen-bonded polar organic vapors. Polarizable vapors like toluene and benzene were sorbed more than nonpolarizable cyclohexane vapors. The sorption results were interpreted in terms of semiempirical models based on concepts of thermodynamic interaction parameter, partition coefficient, and linear solvation energy relationship. The study reveals the potential of sorption/desorption isotherms and kinetics in characterizing the sorption properties of coating materials that are used as an interface in acoustic wave sensors.

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An experimental and theoretical investigation of orientational dependence of H–F couplings in fluoro-olefins

Cited by 39 publications

References 2 publications

Concertedness and E2 elimination reactions: prediction of transition state position and reaction rates using two-dimensional reaction surfaces based on quadratic and quartic approximations

Concertedness and E2 elimination reactions: prediction of transition state position and reaction rates using two-dimensional reaction surfaces based on quadratic and quartic approximations

Stereoselective Palladium‐Catalyzed Four‐Component Cascade Synthesis of Pyrrolidinyl‐, Pyrazolidinyl‐, and Isoxazolidinyl Isoquinolines

Study of sorption/desorption of water and organic vapors on poly(ethylene maleate)‐based sensor‐coating materials using an automated gravimetric analyzer

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