15 September 2022

Nmr-Monitoring Of H/D Exchange Reaction Of Ketones In Solutions Of Imidazolium Ionic Liquids

NMR spectroscopy was used to study hydrogen-deuterium exchange in CH3, CH2 and CH moieties of ketones dissolved in mixtures of solvents containing exchangeable deuteriums and imidazolium ionic liquids (IL) acting as catalysts. Factors affecting the efficiency of the exchange, as well as the role of the deuterated solvent, temperature and concentration, were investigated. Depending on the sample composition and temperature, the degree of deuteration can reach different values at equilibrium state, and the exchange rate can vary from several minutes to several months. ILs with OAc anions and with ethyl chain cations exhibit significant catalytic properties and high degrees of deuteration (up to 98%), which can be achieved by consecutive deuteration cycles. A convenient practical protocol for monitoring the exchange process by NMR spectroscopy and calculating the degree of deuteration was developed and can be used for various molecular systems.

Reference: J. Mol. Liq., 2022, 362, 119746

DOI: 10.1016/j.molliq.2022.119746