Proton–deuterium exchange of acetone catalyzed in imidazolium-based ionic liquid–D₂O mixtures

Abstract

The reaction of the proton–deuterium exchange of acetone in imidazolium-based ionic liquid (IL)–deuterium oxide mixtures was studied in detail via NMR spectroscopy.

Synthesis and Comprehensive Study of Quaternary-Ammonium-Based Sorbents for Natural Gas Sweetening

“…However, the protons of the amino group (taurate anion) were invisible in the spectrum. This observation could be explained by deuterium exchange with protons of deuterated solvent [32]. Three methyl protons of acetate anion appeared as a singlet at 2.09 ppm (Figure 4).…”

Long range deuterium isotope effects on 13C NMR chemical shifts of 2-alkanones in CD3OD solutions of imidazolium acetate ionic liquids

“…1) and was demonstrated in details for acetone. 8 The H/D substitution occurs in methyl group via the keto-enol tautomerization and four isotopomers with n ¼ 0, 1, 2, and 3 deuterons are generated. Due to the large value of J CD coupling constant and different chemical shis of methyl carbon in CH 3 , CH 2 D, CHD 2 , and CD 3 containing isotopomers, the corresponding signals observed in 13 C{H} NMR spectra are well resolved.…”

“…It consists of 7 superimposed multiplets, corresponding to isotopomers with various numbers of deuteriums in the molecule (from 0 to 6) with the same downeld chemical shi of À0.0587 ppm. 8 However, for non-symmetrical 2-alkanones, the DIE effects depend on the substitution site (C1 or C3), leading to differentiation of multiplets corresponding to different isotopomers with the same number of deuteriums in the molecule. As a result, C2 carbonyl carbon spectral pattern is much more complex (Fig.…”

“…We have observed DIE during the deuteration of acetone due to the exchange reaction via keto-enol tautomerization, occurring in heavy water environment only in the existence of IL served as a catalyst. 8 DIE in 13 C NMR spectra have been rst reported in 1967 only for carbonyl carbon of acetone-d 6 . 9 Later DIE were studied thoroughly in ten compounds by Sergeyev et al 10 In all cases the upeld shi approximately 0.1-0.3 ppm per one substituted deuterium was observed over two bonds, and 0.02-0.04 ppm over three bonds.…”

“…However, H/D exchange reactions occurring in solutions of imidazolium ionic liquids (IL) in deuterated solvents containing exchangeable deuterons (like chloroform-d, methanol-d 6 or heavy water) provide a good opportunity for such studies. 8 Especially attractive is the simultaneous existence of large set of different isotopomers in the reaction mixture and variation of this set over the time.…”