Solvent effect on the protonation of some alkylamines

1980 ◽  
Vol 58 (9) ◽  
pp. 953-958 ◽  
Author(s):  
Alfonso Mucci ◽  
Robert Domain ◽  
Robert L. Benoit
Keyword(s):  
Solvent Effect ◽  
Gas Phase ◽  
Propylene Carbonate ◽  
Vapour Pressure ◽  
Thermodynamic Data ◽  
Solution Thermodynamics ◽  
Heat Of Solution ◽  
Phase Data

Thermodynamic data were obtained at 25 °C for the solution and protonation of six bases B: ammonia, three methylamines, and monoethyl and n-propylamines in dimethylsulfoxide (Me2SO) and propylene carbonate (PC). Vapour pressure, potentiometric, and calorimetric determinations were carried out. The solvent effect on the basicity order and protonation of the amines is analysed by using gas phase data and comparing the solution thermodynamics of gaseous B and BH+. The heat of solution of B in both solvents is close to its heat of condensation. The solution data for BH+ are discussed in terms of two recent hydration data interpretations.

scholarly journals Basicity of N-substituted anilines and pyridine in dimethylsulfoxide

1981 ◽  
Vol 59 (10) ◽  
pp. 1501-1504 ◽  
Author(s):  
Robert L. Benoit ◽  
Moyra J. Mackinnon ◽  
Léon Bergeron
Keyword(s):  
Gas Phase ◽  
Aromatic Amines ◽  
Ionization Constants ◽  
Heat Of Solution ◽  
Substituted Anilines ◽  
Heat Of Vaporization ◽  
Heats Of Solution ◽  
Phase Data

The ionization constants of the conjugated acids BH+ of aniline, N-methyl- and N,N-dimethylaniline, and pyridine have been determined potentiometrically in Me2SO. The heats of neutralization of the amines B and their heats of solution have been obtained by calorimetry. The pK's and enthalpies of ionization of these BH+ ions and alkylammonium ions are linearly related. Comparisons with gas phase data show that the abnormal basicity order of the amines B in Me2SO is mainly due to the decreasing exothermicity of the heat of solution of the BH+ ions with the number of N—H protons available for H-bonding to Me2SO. The large increase in basicity difference between equally substituted aromatic and alkylamines, when passing from the gas phase to Me2SO, is linked to the larger heat of vaporization of the aromatic amines.

The crystallization of the teschenite from the Lugar Sill, Ayrshire

1968 ◽  
Vol 105 (1) ◽  
pp. 23-34 ◽  
Author(s):  
W. J. Phillips
Keyword(s):  
Gas Phase ◽  
Vapour Pressure ◽  
Gas Bubbles

SUMMARYTwelve stages in the crystallization of the teschenite are defined by the commencement or cessation of crystallization of particular minerals. Ocellar structures, outlined by tangentially arranged biotite flakes, developed in liquid pockets after the sill had begun to consolidate, due to the coalescence of crystalline masses. It is thought that these ocellar structures were formed by the growth of gas bubbles and that this caused the expansion and fracturing of the partially consolidated sill. It is argued that the separation of the gas phase was the result of a retrograde increase in the vapour pressure during crystallization.

The vibrational force field of diazirine from gas phase data and from ab initio calculations

1994 ◽  
Vol 320 ◽  
pp. 107-123 ◽  
Author(s):  
Brenda P. Winnewisser ◽  
Alberto Gambi ◽  
Manfred Winnewisser
Keyword(s):  
Force Field ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Gas Phase ◽  
Phase Data

scholarly journals Identification of ion pairs in solution by IR spectroscopy: crucial contributions of gas phase data and simulations

2019 ◽  
Vol 21 (24) ◽  
pp. 12798-12805 ◽  
Author(s):  
Sana Habka ◽  
Thibaut Very ◽  
Jeremy Donon ◽  
Vanesa Vaquero-Vara ◽  
Benjamin Tardivel ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Gas Phase ◽  
Ion Pairs ◽  
Phase Data

Ion pairs between sodium and acetate are evidenced by IR spectroscopy in solution with the help of gas phase data and simulations.

Protonation of purines and related compounds in dimethylsulfoxide and water

1985 ◽  
Vol 63 (6) ◽  
pp. 1228-1232 ◽  
Author(s):  
Robert L. Benoit ◽  
Danielle Boulet ◽  
Luc Séguin ◽  
Monique Fréchette
Keyword(s):  
Solvent Effect ◽  
Functional Groups ◽  
Thermodynamic Data ◽  
Ionization Constants ◽  
Enthalpies Of Transfer ◽  
Heats Of Solution ◽  
Bonding Properties ◽  
Related Compounds

The ionization constants of the conjugated acids BH+ of purine, adenine, 9-methyladenine, adenosine, guanine, and hypoxanthine, and of the related compounds imidazole, N-methylimidazole, benzimidazole, and 4-amino-2,6-dimethylpyrimidine have been determined potentiometrically in Me2SO. The heats of solution and the heats of protonation of most of these bases have been obtained by calorimetry. Some additional determinations were carried out in water so that thermodynamic data in Me2SO and in water could be compared. Our discussion of the solvent effect on these data is largely based on a consideration of the enthalpies of transfer of B and BH+ and emphasizes the contrasting H-bonding properties of the solvents and of the functional groups on the solutes B and BH+.

Computational Determination of Heats of Formation of Energetic Compounds

1995 ◽  
Vol 418 ◽  
Author(s):  
Peter Politzer ◽  
Jane S. Murray ◽  
M. Edward Grice
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Functional Group ◽  
Solid Phase ◽  
Heats Of Formation ◽  
Energetic Compounds ◽  
Phase Data ◽  
Heats Of Vaporization ◽  
Group Effects

AbstractA recently-developed density functional procedure for computing gas phase heats of formation is briefly described and results for several categories of energetic compounds are summarized and discussed. Liquid and solid phase values can be obtained by combining the gas phase data with heats of vaporization and sublimation estimated by means of other relationships. Some observed functional group effects upon heats of formation are noted.

Studies on the iodide–triiodide equilibrium

1977 ◽  
Vol 55 (5) ◽  
pp. 792-797 ◽  
Author(s):  
Robert L. Benoit ◽  
Michael F. Wilson ◽  
Sing-Yeung Lam
Keyword(s):  
Free Energy ◽  
Solvent Effect ◽  
Gas Phase ◽  
Formation Enthalpy ◽  
Aprotic Solvents ◽  
Free Energies ◽  
Potentiometric Measurements ◽  
Cast Doubt ◽  
Transfer Parameters ◽  
The Enthalpy Of Formation

The solvent effect on the iodide–triiodide equilibrium has been investigated by means of calorimetric and potentiometric measurements. The aprotic solvents studied were nitromethane, nitrobenzene, sulfolane, acetonitrile, propylene carbonate, acetophenone, dimethylformamide, dimethylsulfoxide, and o-dichlorobenzene. The resulting enthalpy and free energy changes imply that the variations of the enthalpies and free energies of transfer of the iodide and triiodide ions probably are small and that there is an important non-coulombic contribution to these transfer parameters. Values were obtained for the enthalpy of formation of two solid triiodides, which together with values for other triiodides, cast doubt on reported calculated lattice enthalpies of triiodides and formation enthalpy of I3− ion in the gas phase. This latter formation enthalpy is found to be, from our solution data, more negative than −22 kcal mol−1.

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