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In this paper, two Natural Deep Eutectic Solvents, glyceline (Gly) and glyceline-water (GlyW), containing choline chloride as acceptor H-bond compound and glycerol as donor H-bond group are studied. For glyceline the mole relation is 1 (choline chloride): 2 (glycerol) and for glyceline-water the mole relation is 1 (choline chloride) : 1.99 (glycerol) : 1.02 water. The ternary NADES has been synthetized and characterized chemically by NMR techniques for this work. Several thermophysical properties in a wide range of temperature (278.15-338.15) K and at atmospheric pressure (0.1 MPa) have been measured for both compounds: density, , speed of sound, , refractive index, , surface tension, , isobaric molar heat capacity, , , kinematic viscosity, , and electric conductivity,. Furthermore, some related properties have been also calculated: isobaric expansibility, , isentropic compressibility, , molar refraction, , entropy and enthalpy of surface formationper unit surface area (Δ and Δ), and dynamic viscosity, , and viscous flow and electrical conductivity activation energies. The results have been discussed in terms of the effect of temperature and the inclusion of water. We conclude that the compound containing water into the structurehas a higher molar volume and a higher fluidity. The binary NADES (Gly) is a more structured liquid than ternary one (GlyW).

Deep eutectic solvents (DESs) are a relatively new type of solvent that have attracted the attention of the scientific community due to their environmentally friendly properties and their versatility in many applications. Many possible DESs have been described and, thus, it is not easy to unequivocally characterize and generalize their properties. This is especially important in the case of the (eco)toxicity information that can be found for these mixtures. In this review, we collect data on the human and environmental toxicity of DESs, with the aim of gathering and exploring the behavioral patterns of DESs. The toxicity data found were analyzed attending to different factors: hydrogen bond donors or acceptors that form part of the eutectic mixture, pH, and the presence of organic acids in the DES molar ratio of the components, or interactions with natural compounds. In the case of ecotoxicity, results generally depend on the biomodel studied, along with other factors that have been also revised. Finally, we also carried out a revision of the biodegradation of DESs.

Densities of levulinic acid, ethyl levulinate, butyl levulinate, furfural, and furfuryl alcohol have been measured using a high-pressure, high-temperature vibrating tube densimeter system over a temperature range from 283.15 to 338.15 K and a pressure range from 0.1 to 60.0 MPa. In the case of levulinic acid, the temperature range was from 308.15 to 338.15 K. The experimental densities have been satisfactorily correlated with the temperature and pressure using the TRIDEN equation. Finally, from the measured densities, some thermodynamic properties, isobaric thermal expansion and isothermal compressibility, have been calculated.

Abstract:The increasing interest in the development of novel green solvents has led to the synthesis of benign alternative products with minimized environmental impacts.However, most of published studies on green solvents focus primarily on their physicochemical properties, with limited emphasis on absence of ecotoxicological assessment. In this study, we evaluated the acute ecotoxicity of four levulinates (levulinic acid, methyl levulinate, ethyl levulinate and butyl levulinate) on freshwater algae (Chlamydomonas reinhardtii), bacteria (Vibrio fischeri), daphnids (Daphnia magna) and earthworms (Eisenia foetida) using various dose-response tests. As a general trend, the toxicity of levulinate esters in aquatic exposure (assessed as the EC 50 ) increased as a function of increasing alkyl chain length; accordingly, the most toxic compound for the aquatic organisms was butyl levulinate, followed by ethyl levulinate and methyl levulinate. The most toxic compound for Eisenia foetida (terrestrial exposure) was methyl levulinate, followed by ethyl levulinate, butyl levulinate and levulinic acid; in this case, we observed an inverse relationship between toxicity and alkyl chain length. Based on both the lowest EC 50 found in the aquatic media and the ratio between predicted environmental concentration (PEC) and the predicted no-effect concentration (PNEC), we have estimated the maximum allowable values in the 2 environment for these chemicals to be 1.093 mg L -1 for levulinic acid, 2.761 mg L -1 for methyl levulinate, 0.982 mg L -1 for ethyl levulinate and 0.151 mg L -1 for butyl levulinate.

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