1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

ATR and transmission IR spectroscopy have been used to investigate the state of water in room temperature ionic liquids (RTILs) based on the 1-alkyl-3-methylimidazolium cation with the anions: [PF6]−, [SbF6]−, [BF4]−, [ClO4]−, [CF3SO3]−, [(CF3SO2)2N]−, [NO3]− and [CF3CO2]−. It has been shown that in these RTILs water molecules absorbed from the air are present mostly in the “free”
(not self-associated) state, bound via H-bonding with [PF6]−, [BF4]−, [SbF6]−, [ClO4]−, [CF3SO3]−, [(CF3SO2)2N]− with the concentrations of dissolved water in the range 0.2–1.0 mol dm−3. It has been concluded that most of the water molecules at these concentrations exist in symmetric 1 : 2 type H-bonded complexes: anion...HOH...anion. Additional evidence that the preferred sites of interaction with water molecules are the anions has been obtained from the experiments with RTILs of the 1-butyl-2,3-dimethylimidazolium and 1-butyl-2,3,4,5-tetramethylimidazolium cations. Water molecules can also form associated liquid-like formations in RTILs with anions of stronger basicity such as [NO3]− and [CF3CO2]−. When these RTILs are exposed to air the water concentrations exceed 1.0 mol dm−3. The strength of H-bonding between water molecules and anions increases in the order [PF6]− < [SbF6]− < [BF4]− < [(CF3SO2)2N]− < [ClO4]− < [CF3SO3]− < [NO3]− < [CF3CO2]−. The energies of this H-bonding were estimated from spectral shifts, with the resulting enthalpies being in the range 8–13 kJ mol−1. ATR-IR spectroscopy has also been used to study H-bonding between methanol and RTILs.

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Molecular states of water in room temperature ionic liquids

Ionic liquids: solvent properties and organic reactivity

Sustainable solvents are a topic of growing interest in both the research community and the chemical industry due to a growing awareness of the impact of solvents on pollution, energy usage, and contributions to air quality and climate change. Solvent losses represent a major portion of organic pollution, and solvent removal represents a large proportion of process energy consumption. To counter these issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Much of the focus has been on the environmental credentials of the solvent itself, although how a substance is deployed is as important to sustainability as what it is made from. In this Review, we consider several aspects of the most prominent sustainable organic solvents in use today, ionic liquids, deep eutectic solvents, supercritical fluids, switchable solvents, liquid polymers, and renewable solvents. We examine not only the performance of each class of solvent within the context of the...

Green and Sustainable Solvents in Chemical Processes

Production of nanocrystalline cellulose from lignocellulosic biomass: Technology and applications

Effect of water addition on choline chloride/glycol deep eutectic solvents: Characterization of their structural and physicochemical properties

Surfactant promoting effects on clathrate hydrate formation : Are micelles really involved?

We report the preparation and the study of the properties of novel deep eutectic solvents (DESs) formed by zwitterionic trimethylglicine and high melting point carboxylic acids. These zwitterionic DESs are liquid at room temperature or at temperatures lower than 70 °C and do not have chloride or any metal ions in their composition. These media were characterized in terms of their viscosity, conductivity, density, ionicity (via Walden plots), surface tension and thermal stability. The values observed are similar to other typical DESs, and the mixtures resulted in “poor ionic liquids” in the Walden plot. The values obtained could be correlated to the carboxylic acids' structures. The toxicity of the pure mixtures was evaluated via an FTIR-bioassay on Saccharomyces cerevisiae cells. This method allowed us to define the action of these media as dehydrating agents on eukaryotic model cells, with a mechanism highly correlated with CaCl2, a well-known dehydrating agent. The Glycolic acid/Trimethylglicine eutectic system can be considered a NADES (Natural Deep Eutectic Solvent) and resulted as the best in our set for many reasons. It is formed by natural, renewable, eco-compatible and cheap compounds (both the molecules can be derived from sugar beet) and it can be used in many applications because it has a low melting point (−36 °C) and it is colorless, and therefore suitable for spectroscopic measurements. For these reasons, the solubility of some α-L-amino acids was investigated in this DES, showing a good solubility for aromatic amino acids, which are normally scarcely soluble in water.

Raimondo Germani

Papers

Effect of water addition on choline chloride/glycol deep eutectic solvents: Characterization of their structural and physicochemical properties

Surfactant promoting effects on clathrate hydrate formation : Are micelles really involved?

Novel zwitterionic deep eutectic solvents from trimethylglycine and carboxylic acids: characterization of their properties and their toxicity

Mercury extraction by ionic liquids: temperature and alkyl chain length effect

Novel Brønsted acidic deep eutectic solvent as reaction media for esterification of carboxylic acid with alcohols