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.

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.

Analysis of Aromatic Amines in Industrial Wastewater by Capillary Gas Chromatography-Mass Spectrometry

2000 ◽  
Vol 35 (2) ◽  
pp. 245-262 ◽  
Author(s):  
Francis I. Onuska ◽  
Ken A. Terry ◽  
R. James Maguire
Keyword(s):  
Gas Chromatography ◽  
Aromatic Amines ◽  
Methylene Chloride ◽  
Solid Phase ◽  
Stationary Phases ◽  
Gas Chromatography Mass Spectrometry ◽  
Substituted Anilines ◽  
Environmental Media ◽  
Solid Phase Extraction Cartridge ◽  
Wide Range

Abstract The analysis of aromatic amines, particularly benzidines, at trace levels in environmental media has been difficult because of the lack of suitable deactivated capillary column stationary phases for gas chromatography. This report describes the use of an improved type of column as well as a method for the analysis of anilines and benzidines in water, wastewater and sewage samples. Extraction procedures are applicable to a wide range of compounds that are effectively partitioned from an aqueous matrix into methylene chloride, or onto a solid-phase extraction cartridge. The extracted analytes are also amenable to separation on a capillary gas chromatographic column and transferable to the mass spectrometer. These contaminants are converted to their N-trifluoroacetyl derivatives. Aniline and some substituted anilines, and 3,3’-dichlorobenzidine and benzidine were determined in 24-h composite industrial water, wastewater, primary sludge and final effluent samples at concentrations from 0.03 up to 2760 µg/L.

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.

scholarly journals Regioselective Thiocyanation of Aromatic and Heteroaromatic Compounds Using [2-(Sulfooxy)ethyl]sulfamic Acid as an Efficient, Recyclable Organocatalyst and Novel Difunctional Brønsted Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Sami Sajjadifar ◽  
Saaid Karimian ◽  
Hadi Noorizadeh ◽  
Hojat Veisi
Keyword(s):  
Hydrogen Peroxide ◽  
Aromatic Amines ◽  
Room Temperature ◽  
Simple Procedure ◽  
Sulfamic Acid ◽  
Chlorosulfonic Acid ◽  
Substituted Anilines ◽  
Heteroaromatic Compounds ◽  
Reaction Cycles ◽  
Considerable Loss

A green and simple procedure for the thiocyanation of aromatic and heteroaromatic compounds is described. [2-(Sulfooxy)ethyl]sulfamic acid (SESA) (supported on silica) is easily produced by addition of chlorosulfonic acid to 2-aminoethanol and this catalyst is applied as an efficient, reusable, and heterogeneous catalyst for the thiocyanation of heterocycles, substituted anilines (electron-rich and electron-deficient), and N,N-disubstituted aromatic amines using hydrogen peroxide in the water : ethanol as a solvent at room temperature. The catalyst can be easily recovered and reused for five reaction cycles without considerable loss of activity.

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.

An amorphous-to-amorphous transition in Ni–Zr–B alloys as probed by hydrogen storage

1988 ◽  
Vol 3 (6) ◽  
pp. 1349-1354
Author(s):  
J. H. Harris ◽  
W. A. Curtin
Keyword(s):  
Hydrogen Storage ◽  
Gas Phase ◽  
Hydrogen Absorption ◽  
Structural Transition ◽  
Alloy System ◽  
Absorption Properties ◽  
Amorphous Phases ◽  
Phase Data ◽  
A Site ◽  
Storage Properties

The hydrogen occupation characteristics of the ternary amorphous alloy system Ni–Zr–B are investigated using gas-phase and electrochemical hydrogen-absorption techniques. Boron concentrations of as little as 1% are observed to cause large changes in the hydrogen storage properties relative to the binary Ni–Zr. Generalizations of a site statistical model, which accurately accounted for H storage in thebinary Ni–Zr and is based on tetrahedral interstitial hydrogen sites, cannot account for the hydrogen absorption properties of the boron-containing alloys, suggesting a structural transition between two amorphous phases induced by only 1% boron. A simple model in which the new amorphous phase stores H in higher-coordinated interstitial sites is shown to be consistent with the electrochemical and gas-phase data.

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