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Chemical Reviews May 2017Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review... (Review)
Review
Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review offers a compilation on the main results achieved by the use of ionic-liquid-based processes in the extraction and separation/purification of a large range of bioactive compounds (including small organic extractable compounds from biomass, lipids, and other hydrophobic compounds, proteins, amino acids, nucleic acids, and pharmaceuticals). ILs have been studied as solvents, cosolvents, cosurfactants, electrolytes, and adjuvants, as well as used in the creation of IL-supported materials for separation purposes. The IL-based processes hitherto reported, such as IL-based solid-liquid extractions, IL-based liquid-liquid extractions, IL-modified materials, and IL-based crystallization approaches, are here reviewed and compared in terms of extraction and separation performance. The key accomplishments and future challenges to the field are discussed, with particular emphasis on the major lacunas found within the IL community dedicated to separation processes and by suggesting some steps to overcome the current limitations.
Topics: Amino Acids; Biological Products; Chemical Fractionation; Chemistry Techniques, Analytical; Ionic Liquids; Lipids; Liquid-Liquid Extraction; Nucleic Acids; Pharmaceutical Preparations; Proteins
PubMed: 28151648
DOI: 10.1021/acs.chemrev.6b00550 -
PNAS Nexus Sep 2022The existence of a phase transition between two distinct liquid phases in single-component network-forming liquids (e.g. water, silica, silicon) has elicited...
The existence of a phase transition between two distinct liquid phases in single-component network-forming liquids (e.g. water, silica, silicon) has elicited considerable scientific interest. The challenge, both for experiments and simulations, is that the liquid-liquid phase transition (LLPT) occurs under deeply supercooled conditions, where crystallization occurs very rapidly. Thus, early evidence from numerical equation of state studies was challenged with the argument that slow spontaneous crystallization had been misinterpreted as evidence of a second liquid state. Rigorous free-energy calculations have subsequently confirmed the existence of a LLPT in some models of water, and exciting new experimental evidence has since supported these computational results. Similar results have so far not been found for silicon. Here, we present results from free-energy calculations performed for silicon modeled with the classical, empirical Stillinger-Weber-potential. Through a careful study employing state-of-the-art constrained simulation protocols and numerous checks for thermodynamic consistency, we find that there are two distinct metastable liquid states and a phase transition. Our results resolve a long-standing debate concerning the existence of a liquid-liquid transition in supercooled liquid silicon and address key questions regarding the nature of the phase transition and the associated critical point.
PubMed: 36714873
DOI: 10.1093/pnasnexus/pgac204 -
International Journal of Molecular... May 2016Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display... (Review)
Review
Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?
Topics: Hydrophobic and Hydrophilic Interactions; Ionic Liquids; Ions; Liquid Crystals; Models, Chemical; Models, Molecular; Molecular Conformation; Molecular Structure; Phase Transition; Thermodynamics
PubMed: 27196890
DOI: 10.3390/ijms17050731 -
Materials (Basel, Switzerland) Jun 2020Mechanical jamming of nanoparticles at liquid-liquid interfaces has evolved into a versatile approach to structure liquids with solid-state properties. Ferromagnetic...
Mechanical jamming of nanoparticles at liquid-liquid interfaces has evolved into a versatile approach to structure liquids with solid-state properties. Ferromagnetic liquids obtain their physical and magnetic properties, including a remanent magnetization that distinguishes them from ferrofluids, from the jamming of magnetic nanoparticles assembled at the interface between two distinct liquids to minimize surface tension. This perspective provides an overview of recent progress and discusses future directions, challenges and potential applications of jamming magnetic nanoparticles with regard to 3D nano-magnetism. We address the formation and characterization of curved magnetic geometries, and spin frustration between dipole-coupled nanostructures, and advance our understanding of particle jamming at liquid-liquid interfaces.
PubMed: 32549201
DOI: 10.3390/ma13122712 -
Molecules (Basel, Switzerland) Sep 2022Supported ionic liquid phases offer several advantages related with catalysis. Immobilization of ionic liquid on the solid support provides catalytic activity or... (Review)
Review
Supported ionic liquid phases offer several advantages related with catalysis. Immobilization of ionic liquid on the solid support provides catalytic activity or efficient matrix for active phases, as enzymes or metal compounds. Ionic liquid can be physically adsorbed on the carrier (supported ionic liquid phase) or chemically grafted to the material surface (supported ionic liquid-like phase). The use of supported ionic liquid phases improves mass transport, reduces ionic amount in the process and, most importantly, enables effortless catalyst separation and recycling. Moreover, chemical modification of the surface material with ionic liquid prevents its leaching, enhancing length of catalyst life. Silica-based materials have become an effective and powerful matrix for supported ionic liquid-like phase due to its cost-efficiency, presence of hydroxyl groups on the surface enabling its functionalization, and specific material properties, such as the size and shapes of the pores. For these reasons, supported ionic liquid-like phase silica-based materials are successfully used in the organic catalysis.
Topics: Catalysis; Ionic Liquids; Ions; Silicon Dioxide
PubMed: 36144636
DOI: 10.3390/molecules27185900 -
ACS Omega Nov 2021Emerging ionic liquid lubricants were discovered only 20 years ago. The superior performance of ionic liquids over traditional lubricating fluids have been reviewed,... (Review)
Review
Emerging ionic liquid lubricants were discovered only 20 years ago. The superior performance of ionic liquids over traditional lubricating fluids have been reviewed, including low-temperature fluidity, viscosity-temperature properties, thermal oxidation stability, ultralow volatility, incompressibility, electrical conductivity, friction coefficient under elastohydrodynamic lubrication conditions, friction reduction and antiwear performance under boundary lubrication conditions, environmental friendliness, etc. The applications where ionic liquids are superior to traditional lubricant fluids are presented, including hydrogen compressor lubricating fluids and liquid pistons, oxygen compressor lubricating fluids, hydraulic fluids, space lubricants, vehicle engine oils, industrial gear oils, metalworking fluids, industrial coolant, micro/nano electromechanical system applications, electrical conductive lubricants, etc. The ability of ionic liquids to replace ZDDP, a key additive of lubricating oil, is introduced. The future development prospects of ionic liquid lubricants are analyzed.
PubMed: 34778607
DOI: 10.1021/acsomega.1c04512 -
Scientific Reports 2013Liquids flow, and in this sense are close to gases. At the same time, interactions in liquids are strong as in solids. The combination of these two properties is...
Liquids flow, and in this sense are close to gases. At the same time, interactions in liquids are strong as in solids. The combination of these two properties is believed to be the ultimate obstacle to constructing a general theory of liquids. Here, we adopt a new approach: instead of focusing on the problem of strong interactions, we zero in on the relative contributions of vibrational and diffusional motion. We show that liquid energy and specific heat are given, to a very good approximation, by their vibrational contributions as in solids over almost entire range of relaxation time in which liquids exist as such, and demonstrate that this result is consistent with liquid entropy exceeding solid entropy. Our analysis therefore reveals an interesting duality of liquids not hitherto known: they are close to solids from the thermodynamic perspective and to flowing gases. We discuss several implications of this result.
PubMed: 23851971
DOI: 10.1038/srep02188