Design and Characterization of Sugar-Based Deep Eutectic Solvents Using Conductor-like Screening Model for Real Solvents

Abstract

Inspired by the lack of characterization of natural eutectic and deep eutectic (DES) systems, we studied the solid-liquid equilibria (SLE) of binary and ternary mixtures involving choline chloride and sugars. The densities, viscosities and solvatochromic parameters for the binary systems containing choline chloride, [Ch]Cl, were measured at the eutectic composition, and the water impact on these properties was also investigated in order to address the tailoring of their properties using water. Mixtures of sugars are shown to present an ideal behavior, while their binary mixtures with choline chloride present negative deviations to the ideality, particularly in the sugar solubility curve. Aiming to develop a predictive model to design new sugar based DES, the [Ch]Cl + sugars phase diagrams were used to tune the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) parameters, which was after applied in the estimation of the eutectic points of new ternary DES. The predictions quality was checked experimentally, proving that COSMO-RS can be a useful tool for the design of deep eutectic solvents.

Using COSMO-RS to design choline chloride pharmaceutical eutectic solvents

“…is 31 C. However, the model displayed abnormal innacurate predictions for close-ring sugars (glucose, frutose and saccarose), and aromatica acids (benzoic and salicylic acids). The difficulties herein encountered to describe the choline chloride/sugar systems have already been reported in the literature along with fine-tuning of COSMO-RS parameters to overcome them [30]. If these five systems are disregarded as outliers, the mean deviation of the AB model is decreased to just 12 C. Fig.…”

“…For the mixtures with a paste-like consistency, a visual method with an oil bath previously described elsewhere [30] was employed. The mixtures were gradually heated until complete melting and the temperature was controlled with a PT100 probe (previously calibrated) with a precision of ±0.1 K.…”

“…For the remaining mixtures, the recrystallized solid was crushed in a mortar inside a glove-box and the powder was filled into a glass capillary. The solid-liquid phase diagrams were measured using a melting point device, model M À 565 by Buchi (100e240 V, 50e60 Hz, 150 W), with a temperature resolution of 0.1 K, as previously described [30], and a temperature gradient of 0.1 K min À1 .…”

“…It should be noted that COSMO-RS is not particularly suitable for calculations with ionic species [30,52]. Attempting to minimize this problem, two distinct approaches are investigated in this work.…”

Low Transition Temperature Mixtures (LTTM) Containing Sugars as Potato Starch Plasticizers

“…Characterization of sugar‐based DES, LTTM, and molten salts was presented in many works . These type of media were proposed, e.g., for biomass pretreatment, extraction, production of porous materials from starch/polycaprolactone blends, as polysaccharide solvents, and reaction media/substrates . In this work, we presented for the first time sugar/glycerol‐based LTTM.…”