Year: 2017
Type: article
Abstract: The formation pathways of self- and heteroassociates in the “carboxylic acid – base (tertiary amine / tetraalkylammonium salt) – oxirane” system were investigated. The effect of the steric parameters and solvent characteristics was considered. It was shown that carboxylic acids are highly complexable. The hydrogen-bonded acid dimers, acid – oxirane, and acid – base associates are also capable to form secondary complexes. The dependence of processes of primary and secondary association on solvent polarity and acid-base properties of system components was established. It was stated that the inert aprotic solvents promote primary and secondary complex formation in the “carboxylic acid – base – oxirane” system, but the primary association is the dominant interaction process. The effect of the nucleophilic and base properties of organic nitrogen-containing base on the association degree of the system components was estimated. The decrease of steric hindrances at the nitrogen atom in the base results in decrease of concentration of the complex acid – base, and the temperature decrease has similarly effect. It was established that more nucleophilic and more polar then amines, quaternary ammonium salts tend to form ionic complexes, yet increase of system temperature shifts the equilibrium towards formation of molecular complexes. The existence of all the considered types of hydrogen-bonded complexes was confirmed by experimental spectral methods: IR and UV spectroscopy. The spectroscopic studies were carried in two solvents: non-polar aprotic carbon tetrachloride and polar aprotic epichlorohydrin. The quantitative characteristics of complexes: acid – acid, acid – oxirane, acid – base and their effect on reaction rate and its mechanism were analyzed.
Authors: Донецький національний університет імені Василя Стуса, K. S. Yutilova, Yu. N. Bespal’ko, Донецький національний університет імені Василя Стуса, E. N. Shved, Донецький національний університет імені Василя Стуса
Institution: Vasyl' Stus Donetsk National University
Language: Ukrainian
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2889518446