Dielectric, acoustic, densimetric and viscosimetric investigations of the tributylamine + propionic acid system

TGA–FTIR study of the vapors released by triethylamine–acetic acid mixtures

“…The formation of the A 1 C 3 complex in triethylamine-acetic acid mixtures is supported by the sharp viscosity maximum observed at the 1:3 amine to acid mole ratio [16]. The existence of an A 1 C 2 complex has also been reported [12,18,[23][24]. When the tertiary amine is replaced with a secondary or a primary amine the situation changes dramatically.…”

“…This was also theoretically predicted by ab initio calculations for the trimethylamine-formic acid and propylamine-propionic acid systems [22,30]. The ionic nature of the complexes was confirmed by both mid and near infrared spectroscopy [20,21,[24][25], FT-Raman [17], 1 H-NMR and 13 C-NMR [15,31], dielectric spectroscopy, conductivity measurements [18,23], melting and boiling point measurements, ultrasound absorption and relaxation spectroscopy [12,24,[32][33], and combinations of different measurement techniques including density, optical refractive index, and shear viscosity [23].…”

“…The A 1 C 1 ionic complex requires stabilization and ab initio calculations showed that, at equimolar mixing ratios, the formation of an A 2 C 2 complex is more likely [17]. In the absence of water and in the presence of excess carboxylic acid, the A 1 C 1 complex is stabilized by reacting with the cyclic dimers of the carboxylic acid forming the A 1 C 3 complex [12,17,18,[21][22][23][24]. The formation of the A 1 C 3 complex in triethylamine-acetic acid mixtures is supported by the sharp viscosity maximum observed at the 1:3 amine to acid mole ratio [16].…”

“…The interactions between amines (A) and carboxylic acids (C) have been comprehensively studied [12][13][14][15][16][17][18]. Amines and carboxylic acid mixtures interact strongly via hydrogen bonding [12,15].…”

Кислотно-Основні Взаємодії В Двокомпонентній Системі «карбонова Кислота – Апротонний Розчинник».

“…в присутствии катализаторов основной природы в реакции (1) важным является рассмотрение особенностей состояния протонодонорных нуклеофилов и их поведения с основаниями в апротонных растворителях. Кислотно-основные взаимодействия в апротонных растворителях представляют собой равновесный процесс, результат которого зависит от индивидуального поведения кислот и оснований в растворах [3].…”