The Gas-Phase Acidity Order of Some Inorganic Acids

1971 ◽  
Vol 49 (6) ◽  
pp. 979-981 ◽  
Author(s):  
L. Brewster Young ◽  
E. Lee-Ruff ◽  
D. K. Bohme
Keyword(s):  
Gas Phase ◽  
Thermochemical Data ◽  
Flowing Afterglow ◽  
Gas Phase Acidity ◽  
Inorganic Acids

The gas-phase acidity order at 300 °K of the inorganic acids, water, ammonia, and hydrogen has been directly determined using the flowing afterglow technique. The order established is H2O > H2 > NH3, water being the strongest acid in this series. This result is inconsistent with recent calculations, current available thermochemical data, and the order found in solution.

Absolute gas-phase acidities of CH3NH2, C2H5NH2, (CH3)2 NH, and (CH3)3N

1976 ◽  
Vol 54 (10) ◽  
pp. 1624-1642 ◽  
Author(s):  
Gervase I. Mackay ◽  
Ronald S. Hemsworth ◽  
Diethard K. Bohme
Keyword(s):  
Equilibrium Constant ◽  
Gas Phase ◽  
Equilibrium Constants ◽  
Heats Of Formation ◽  
Molecular Orbital Calculations ◽  
Electron Affinities ◽  
Flowing Afterglow ◽  
Experimental Assessment ◽  
Gas Phase Acidity ◽  
Conjugate Bases

The flowing afterglow technique has been employed in measurements of the rate and equilibrium constants at 296 ± 2 K for reactions of the type[Formula: see text]and[Formula: see text]where R1 and R2 may be H, CH3, or C2H5. The equilibrium constant measurements provided absolute values for the intrinsic (gas-phase) acidities of the Brønsted acids CH3NH2, C2H5NH2, (CH3)2NH, and (CH3)3N, the heats of formation of their conjugate bases, and the electron affinities of the corresponding radicals R1R2N. Proton removal energies, ΔG0298/(kcal mol−1), were determined to be 395.7 ± 0.7 for [Formula: see text] 391.7 ± 0.7 for [Formula: see text] 389.2 ± 0.6 for [Formula: see text] and > 396 for [Formula: see text] Heats of formation, ΔH0f.,298, were determined to be 30.5 ± 1.5 for CH3NH−, 21.2 ± 1.5 for C2H5NH−, and 24.7 ± 1.4 for (CH3)2N−. Electron affinities (in kcal mol−1) were determined to be 13.1 ± 3.5 for CH3NH, 17 ± 4 for C2H5NH, and 14.3 ± 3.4 for (CH3)2N. These results quantify earlier conclusions regarding the intrinsic effects of substituents on the gas-phase acidity of amines and provide an experimental assessment of recent molecular orbital calculations of proton removal energies for alkylamines.

scholarly journals Experimental and Computational Studies on the Gas-Phase Acidity of 5,5-Dialkyl Barbituric Acids

2021 ◽  
Author(s):  
Juan Z. Dávalos-Prado ◽  
Javier González ◽  
Josep M. Oliva-Enrich ◽  
Emma J. Urrunaga ◽  
Alexsandre F. Lago
Keyword(s):  
Gas Phase ◽  
Computational Studies ◽  
Gas Phase Acidity

Ab initio calculation of the thermochemical data on the H3O++H2O=H5O+2 gas‐phase clustering

1984 ◽  
Vol 80 (4) ◽  
pp. 1576-1578 ◽  
Author(s):  
Shinichi Yamabe ◽  
Tsutomu Minato ◽  
Kimihiko Hirao
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Ab Initio Calculation ◽  
Thermochemical Data

An experimental study of the reactivity of the hydroxide anion in the gas phase at room temperature, and its perturbation by hydration

1981 ◽  
Vol 59 (11) ◽  
pp. 1615-1621 ◽  
Author(s):  
Scott D. Tanner ◽  
Gervase I. Mackay ◽  
Diethard K. Bohme
Keyword(s):  
Experimental Study ◽  
Proton Transfer ◽  
Gas Phase ◽  
Rate Constants ◽  
Room Temperature ◽  
Gas Phase Reactions ◽  
Flowing Afterglow ◽  
Hydroxide Anion

Flowing afterglow measurements are reported which provide rate constants and product identifications at 298 ± 2 K for the gas-phase reactions of OH− with CH3OH, C2H5OH, CH3OCH3, CH2O, CH3CHO, CH3COCH3, CH2CO, HCOOH, HCOOCH3, CH2=C=CH2, CH3—C≡CH, and C6H5CH3. The main channels observed were proton transfer and solvation of the OH−. Hydration with one molecule of H2O was observed either to reduce the rate slightly and lead to products which are the hydrated analogues of the "nude" reaction, or to stop the reaction completely, k ≤ 10−12 cm3 molecule−1 s−1. The reaction of OH−•H2O with CH3—C≡CH showed an uncertain intermediate behaviour.

scholarly journals Gas-phase acidity of sulfonamides: implications for reactivity and prodrug design

Tetrahedron ◽  
2005 ◽  
Vol 61 (10) ◽  
pp. 2705-2712 ◽  
Author(s):  
J.R.B. Gomes ◽  
P. Gomes
Keyword(s):  
Gas Phase ◽  
Gas Phase Acidity

Gas-phase proton-transfer reactions of the hydronium ion at 298 K

1979 ◽  
Vol 57 (12) ◽  
pp. 1518-1523 ◽  
Author(s):  
Gervase I. Mackay ◽  
Scott D. Tanner ◽  
Alan C. Hopkinson ◽  
Diethard K. Bohme
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Rate Constants ◽  
Transfer Reactions ◽  
Flowing Afterglow ◽  
Hydronium Ion ◽  
Proton Transfer Reactions

Rate constants measured with the flowing afterglow technique at 298 ± 2 K are reported for the proton-transfer reactions of H3O+ with CH2O, CH3CHO, (CH3)2CO, HCOOH, CH3COOH, HCOOCH3, CH3OH, C2H5OH, (CH3)2O, and CH2CO. Dissociative proton-transfer was observed only with CH3COOH. The rate constants are compared with the predictions of various theories for ion–molecule collisions. The protonation is discussed in terms of the energetics and mechanisms of various modes of dissociation.

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