Synthesis and characterization of a lipase-friendly DES based on cholinium dihydrogen phosphate

Abstract

The main objective of the present work was to synthesize and characterize three novel lipase-friendly deep eutectic solvents (DESs) using cholinium dihydrogen phosphate (N1112OHDHP) as hydrogen bond acceptor and ethylene glycol (EG) and/or glycerol (GL) as hydrogen bond donors in the following proportions: N1112OHDHP:EG (molar ratio 1:2), N1112OHDHP:GL (molar ratio 1:2) and N1112OHDHP:EG:GL (molar ratio 1:1:1). FTIR, 1H NMR, TGA and DSC were employed to shed light on their distinctive structural characteristics. Density, refractive index and dynamic viscosity were also measured at different temperatures, and the experimental data were correlated with several well-known equations. Finally, the suitability of the newly synthesized DESs to be employed in biocatalytic reactions was demonstrated by analysing the activity of a commercial enzyme (Candida antarctica lipase B) after being in contact with them.