Determination of the Gas-Phase Basicity of Betaine and Related Compounds Using the Kinetic Method

1996 ◽  
Vol 118 (1) ◽  
pp. 231-232 ◽  
Author(s):  
Jeffrey S. Patrick ◽  
Sheng S. Yang ◽  
R. Graham Cooks
Keyword(s):  
Gas Phase ◽  
Kinetic Method ◽  
Related Compounds

scholarly journals Experimental and Theoretical Investigation on the Thermochemistry of 3-Methyl-2-benzoxazolinone and 6-Nitro-2-benzoxazolinone

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 24
Author(s):  
Ana L. R. Silva ◽  
Vânia M. S. Costa ◽  
Maria D. M. C. Ribeiro da Silva
Keyword(s):  
Gas Phase ◽  
Structural Characteristics ◽  
Enthalpies Of Formation ◽  
Calvet Microcalorimetry ◽  
Static Bomb ◽  
High Level ◽  
The Relationship ◽  
Related Compounds ◽  
Enthalpies Of Sublimation

The determination of the reliable thermodynamic properties of 2-benzoxazolinone derivatives is the main goal of this work. Some correlations are established between the energetic properties determined and the structural characteristics of the title compounds, and the reactivity of this class of compounds is also evaluated. Static-bomb combustion calorimetry and high-temperature Calvet microcalorimetry were used to determine, respectively, the standard molar enthalpies of formation in the solid state and the standard molar enthalpies of sublimation, both at T = 298.15 K. Using the results obtained for each compound, the respective gas-phase standard molar enthalpy of formation was derived. High-level quantum chemical calculations were performed to estimate the same property and the results evidence good accordance. Moreover, the gas-phase relative thermodynamic stability of 2-benzoxazolinone derivatives was also evaluated using the respective gas-phase standard molar Gibbs energy of formation. In addition, the relationship between the energetic and structural characteristics of the benzoxazolinones is presented, evidencing the enthalpic increments associated with the presence of a methyl and a nitro groups in the molecule, and this effect is compared with similar ones in other structurally related compounds.

Gas-Phase Infrared Spectroscopy for Determination of Double-Bond Configuration of Some Polyunsaturated Pheromones and Related Compounds

1995 ◽  
Vol 67 (9) ◽  
pp. 1558-1567 ◽  
Author(s):  
Athula B. Attygalle ◽  
Ales. Svatos ◽  
Charles. Wilcox ◽  
Simon. Voerman
Keyword(s):  
Infrared Spectroscopy ◽  
Double Bond ◽  
Gas Phase ◽  
Related Compounds

Structure, Thermochemistry and Reactivity of Protonated Glycolaldehyde

2001 ◽  
Vol 7 (4-5) ◽  
pp. 351-357 ◽  
Author(s):  
Guy Bouchoux ◽  
Florence Penaud-Berruyer ◽  
William Bertrand
Keyword(s):  
Gas Phase ◽  
Kinetic Method ◽  
Critical Energy ◽  
Protonated Form ◽  
Heats Of Formation ◽  
Molecular Orbital Calculations ◽  
Perfect Agreement ◽  
Stable Conformation ◽  
Water Complex

Structures and relative energies of various conformers of the simplest sugar, glycolaldehyde, 1, and its protonated form, [1H]+, were investigated by ab initio molecular orbital calculations. The 298 K heats of formation of the most stable conformers, deduced from the atomization energies at the G2 level, are equal to Δ fH°(1) = −324.8 kJ mol−1 and Δ fH°[1H]+ = 426.0 kJ mol−1. The corresponding proton affinity value is PA(1) = 779.8 kJ mol−1, in perfect agreement with the experimental determination of 783.3 ± 3.8 kJ mol−1 obtained by the kinetic method. A gas-phase basicity value, GB(1), of 745–748 kJ mol−1 is also deduced from theory and experiment. The exclusive dissociation channel of protonated glycolaldehyde, [1H]+, is water loss which leads essentially to the acylium ion [CH3CO]+. The corresponding potential energy profile, investigated at the MP2/6–31G* level, reveals a route via a [CH3CO]+ / water complex after an energy determining step involving a simultaneous 1,2-hydrogen migration and C–O bond elongation. The critical energy of the reaction, evaluated at the G2(MP2,SVP)level, is 170 kJ mol −1 above the most stable conformation of the [1H]+ ion. The 298 K heats of formation of the three most stable [C2H3O]+ ions have been calculated at the G2 level: Δ fH°[CH3CO]+ = 655.0 kJ mol−1, Δ fH°[CH2COH]+ = 833.0 kJ mol−1, Δ fH°[c-CH2CHO]+ = 886.2 kJ mol−1.

Liquid Chromatographic Determination of Amiodarone Hydrochloride and Related Compounds in Raw Materials and Tablets

1994 ◽  
Vol 77 (6) ◽  
pp. 1447-1453 ◽  
Author(s):  
Pauline M Lacrok ◽  
Norman M Curran ◽  
Wing-Wah Sy ◽  
Dennis K J Goreck ◽  
Pierre Thibault ◽  
...  
Keyword(s):  
Raw Materials ◽  
Chromatographic Determination ◽  
Raw Material ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Amiodarone Hydrochloride ◽  
Related Compounds

Abstract A liquid chromatographic method for the determination of amiodarone hydrochloride and 10 related compounds in drug raw material and for assay of drug in tablets was developed. The method specifies a 3 jxm Hypersil nitrile column (150 × 4.6 mm), a mobile phase of 1 + 1 acetonitrile–ammonium acetate buffer (0.1 M adjusted to pH 6.0 with 0.1 M acetic acid), a flow rate of 1 mL/min, and detection at 240 nm. The lower limit of quantitation of the related compounds is 0.02% or less. Drug contents in 2 raw material samples were 100.1 and 99.9% and ranged from 98.2 to 99.4% in 3 tablet formulations. Impurity levels in 2 samples of raw material from different manufacturers were ca 0.4%. The presence of 3 of the known related compounds in these samples was confirmed by liquid chromatographymass spectrometry. The method applied to raw materials was evaluated by a second laboratory and found to be satisfactory.

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