Registration Number
0221U101568,
0120U100324
, R & D reports
Title
Regioselectivity of epichlorohydrin acidolysis: effect of steric factor and solvent polarity
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Head
Shved Olena M, Доктор хімічних наук
Registration Date
22-01-2021
Organization
Vasyl' Stus Donetsk National University
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Acidolysis of 2-(chloromethyl)oxirane (epichlorohydrin) by acetic and benzoic acids in the presence of tetraalkylammonium halides in binary solvent epichlorohydrin:tetrahydrofuran (1:1 by volume) is investigated by the methods of chemical kinetics, computer modeling and NMR spectroscopy. It is found that this is a zero-order reaction with respect to the acid and a first-order one with respect to the catalyst. The products of the reaction are chlorohydrin esters with «normal» (n-P) and «abnormal» (a-P) structures. It is determined that the reaction rate depends on both the nature and structure of the acid reagent and catalyst and the polarity of the solvent. Benzoic acid is found to exhibit a higher reactivity than acetic acid. The catalytic activity of tetraalkylammonium halides increases with increasing ion radius and nucleophilicity of the salt anion. Reduction of the polarity of the solvent (epichlorohydrin and binary mixture of epichlorohydrin:tetrahydrofuran) contributes to the increase of the reaction rate and its regioselectivity (the formation of the «normal» product n-P). The regioselectivity of the reaction is almost independent of the nature of the acid and increases with an increase in the steric factor. A preferential formation of the ester n-P corresponds to the essential contribution of the SN2 mechanism to the nucleophilic opening of oxirane ring. A symbatic increase in the reactivity of carboxylic acids and the steric factor in the reaction system «carboxylic acid – 2-(chloromethyl)oxirane – tetraalkylammonium halide» allows to identifying the mechanism of the catalytic reaction, which corresponds to the mechanism of anion transfer of a nucleophilic reagent by anion pair.
Product Description
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Bakhalova Ievheniia A.
Bespal'ko Yuliya M.
Sytnyk Nataliia S.
Shpan'ko Igor V.
Yutilova Kseniia S.
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2021-01-22
