RELATIONSHIP BETWEEN VARIOUSLY ASSOCIATED MOLECULES IN THE HF–Et2CO SOLUTION
G. V. Yukhnevich, E. G. Tarakanova
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
Keywords: binary liquid system, IR spectroscopy, hydrogen bond, heteroassociates, hydrogen fluoride, diethyl ketone
Abstract
Data on the relationship between the molecules involved in various heteroassociates (HAs) and «free» molecules in the HF-Et2CO binary liquid system (BLS) are obtained by two independent methods: experimental and computational. The first method is applicable in the 0:1-6:1 molar range provided that the IR spectrum of the solvent molecule contains a band whose frequency and intensity can be measured when this molecule passes from the «free state» to the composition of all Has present in BLS. The second method is based on taking into account the material balance between the «free» molecules and molecules involved in various HAs of the solvent and HF. This method requires the knowledge of stoichiometric ratios of molecules in HAs and concentrations at which they appear in the solution. It is shown that in HF-Et2CO BLS, starting from the molar fraction of HF of ~0.25, the majority of molecules is involved in the composition of the complexes, and at the molar fraction of HF of ~0.50-0.92 already 90-100% of molecules of the solution form HAs.
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