Jaap van Spronsen

Natural deep eutectic solvents as new potential media for green technology.

Developing new green solvents is one of the key subjects in Green Chemistry. Ionic liquids (ILs) and deep eutectic solvents, thus, have been paid great attention to replace current harsh organic solvents and have been applied to many chemical processing such as extraction and synthesis. However, current ionic liquids and deep eutectic solvents have still limitations to be applied to a real chemical industry due to toxicity against human and environment and high cost of ILs and solid state of most deep eutectic solvents at room temperature. Recently we discovered that many plant abundant primary metabolites changed their state from solid to liquid when they were mixed in proper ratio. This finding made us hypothesize that natural deep eutectic solvents (NADES) play a role as alternative media to water in living organisms and tested a wide range of natural products, which resulted in discovery of over 100 NADES from nature. In order to prove deep eutectic feature the interaction between the molecules was investigated by nuclear magnetic resonance spectroscopy. All the tested NADES show clear hydrogen bonding between components. As next step physical properties of NADES such as water activity, density, viscosity, polarity and thermal properties were measured as well as the effect of water on the physical properties. In the last stage the novel NADES were applied to the solubilization of wide range of biomolecules such as non-water soluble bioactive natural products, gluten, starch, and DNA. In most cases the solubility of the biomolecules evaluated in this study was greatly higher than water. Based on the results the novel NADES may be expected as potential green solvents at room temperature in diverse fields of chemistry.

Are Natural Deep Eutectic Solvents the Missing Link in Understanding Cellular Metabolism and Physiology

Over the past decade, metabolomics has developed into a major tool for studying the metabolism of organisms and cells, and through this approach much has been learned about metabolic networks and the reactions of organisms to various external conditions ([Lay et al., 2006][1]). Most of this work

Ionic Liquids and Deep Eutectic Solvents in Natural Products Research: Mixtures of Solids as Extraction Solvents

Mixtures of solid chemicals may become liquid under certain conditions. These liquids are characterized by the formation of strong ionic (ionic liquids) or hydrogen bonds (deep eutectic solvents). Due to their extremely low vapor pressure, they are now widely used in polymer chemistry and synthetic organic chemistry, yet little attention has been paid to their use as extraction solvents of natural products. This review summarizes the preparation of ionic liquids and deep eutectic solvents with natural product components and recent progress in their applications to the extraction and analysis of natural products as well as the recovery of extracted compounds from their extracts. Additionally, various factors affecting extraction features of ionic liquids and deep eutectic solvents, as well as potential useful technologies including microwave and ultrasound to increase the extraction efficiency, are discussed.

Recovery of pure products from ionic liquids using supercritical carbon dioxide as a co-solvent in extractions or as an anti-solvent in precipitations

In this paper two advanced methods for separation and purification of products from ionic liquids by using supercritical carbon dioxide as a co-solvent in extractions or as an anti-solvent in precipitations are demonstrated. As an example, the recovery of the product N-acetyl-(S)-phenylalanine methyl ester (APAM) from the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) was studied experimentally. APAM is the product of the asymmetric hydrogenation of methyl-(Z)-α-acetamidocinnamate (MAAC). For extraction of the product, the solubility of APAM in CO2 should be sufficiently high. This solubility is 1.78 g kg−1 at 12.0 MPa and 323 K, whereas [bmim][BF4] has a negligible solubility in scCO2. The extracted product was found to contain no detectible amount of ionic liquid. The solubility of the reactant MAAC in scCO2 is five times lower than the solubility of APAM, which means that a selectivity towards extraction of APAM exists. The product APAM was also precipitated out of the ionic liquid phase using scCO2 as an anti-solvent, enabled by the lower solubility of APAM in ionic liquid/scCO2 mixtures compared to the solubility in the pure ionic liquid at atmospheric conditions (650 g l−1). For example, the solubility of APAM in ionic liquid + scCO2 (1∶1.34 g g−1) at 313 K and 18.0 MPa is 162 g l−1. After precipitation the formed crystals can be washed using CO2 to obtain pure product.

Crystallization of an organic compound from an ionic liquid using carbon dioxide as anti-solvent

In this paper the anti-solvency behavior of supercritical carbon dioxide (CO2) as a way to recover an organic compound from an ionic liquid by crystallization is explored. As an example, the conditions for crystallization of the organic compound methyl-(Z)-α-acetamido cinnamate (MAAC) from the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim+][BF4−]) using supercritical CO2 as anti-solvent are studied experimentally by measuring the phase behavior of the ternary system [bmim+][BF4−] + CO2 + MAAC. MAAC can be recovered from [bmim+][BF4−] by either using a shift to higher CO2 concentrations at constant temperature (anti-solvent crystallization) or by using a shift to lower temperatures at constant CO2 concentration (thermal shift).

Solubility of carbon dioxide in systems with [bmim][BF4] and some selected organic compounds of interest for the pharmaceutical industry

This work presents phase equilibrium data of the ternary system CO2 + [bmim][BF4] + solute. Three different organic compounds were studied as the solute in the ternary system: 1-methyl-3-phenylpiperazine (MPhPz), 2-chloro-nicotinonitrile (NtN) and 2-(4-methyl-2-phenyl-1-piperazinyl)-3-pyridinecarbonitrile (PCN). Experiments were carried out in a pressure and temperature range of 1–14 MPa and 343.15–443.15 K, respectively. Samples were prepared with CO2 molar fractions of 0.10 until 0.40 for the system with NtN as the solute, and 0.20 for the other two systems for comparison. The data collected show how the various solutes affect the phase behavior of the binary system CO2 + [bmim][BF4], and at which conditions homogeneous phase can be obtained.