: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Sustainable technologies applied to energy-related applications should develop a pivotal role in the next decades. In particular, carbon dioxide capture from flue gases emitted by fossil-fueled power plants should play a pivotal role in controlling and reducing the greenhouse effect. Therefore, the development of new materials for carbon capture purposes has merged as central research line, for which many alternatives have been proposed. Ionic liquids (ILs) have emerged as one of the most promising choices for carbon capture, but in spite of their promising properties, some serious drawbacks have also appeared. Deep eutectic solvents (DESs) have recently been considered as alternatives to ILs that maintain most of their relevant properties, such as task-specific character, and at the same time avoid some of their problems, mainly from economic and environmental viewpoints. DES production from low-cost and natural sources, together with their almost null toxicity and total biodegradability, makes these sol...

Deep Eutectic Solvents: Physicochemical Properties and Gas Separation Applications

The thermal and physicochemical properties of protic ionic liquids (PILs) are reported. It is highly evident that there has been an extensive range of alkylammonium, imidazolium, and heterocyclic cations paired with many organic and inorganic anions that have been employed to prepare PILs. There has been strong interest in modifying the properties of PILs through the addition of water or other molecular solvents. For many applications, the presence of some water in the PILs is not detrimental, and instead leads to enhanced solvent properties such as lower viscosity, higher conductivities, and lower melting points. It remains an issue of definition though of how to refer to these resulting protic solutions. There is also an ongoing difficulty surrounding how to describe the proton activity in the PILs, analogous to pH in aqueous systems. For a broad range of applications, it has been reported that the acidity/basicity of the PIL or PIL-solvent system is crucial for their beneficial properties. It is expected that the fundamental properties of PILs will continue to be explored, along with continued interest in many existing and new applications, such as in electrochemistry, organic and inorganic synthesis, and biological applications. In particular, there has been a significant interest in a broad- range of PILs for use as electrolytes and incorporation in polymer electrolytes for fuel cells, and other energy storage devices.

Protic Ionic Liquids: Evolving Structure–Property Relationships and Expanding Applications

The inherent structure tunability, good affinity with CO2, and nonvolatility of ionic liquids (ILs) drive their exploration and exploitation in CO2 separation field, and has attracted remarkable interest from both industries and academia. The aim of this Review is to give a detailed overview on the recent advances on IL-based materials, including pure ILs, IL-based solvents, and IL-based membranes for CO2 capture and separation from the viewpoint of molecule to engineering. The effects of anions, cations and functional groups on CO2 solubility and selectivity of ILs, as well as the studies on degradability of ILs are reviewed, and the recent developments on functionalized ILs, IL-based solvents, and IL-based membranes are also discussed. CO2 separation mechanism with IL-based solvents and IL-based membranes are explained by combining molecular simulation and experimental characterization. Taking into consideration of the applications and industrialization, the recent achievements and developments on the t...

Ionic-Liquid-Based CO2 Capture Systems: Structure, Interaction and Process

Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

Acidic Ionic Liquids.

Ionic liquids (ILs) have been widely applied for CO2 separation owing to their distinctive properties, such as nonvolatility, tunability of structures, and good affinity with CO2. IL-based membranes exhibit hybrid properties of both ILs and membranes, which is a prospective method to achieve efficient CO2 separation from other light gases. This chapter principally reviewed the research progresses of IL-based membranes for CO2 separation, including supported IL membranes, poly(ionic liquid) membranes, and IL-based polymer membranes. The CO2 permeability and selectivity of membrane, the influences of IL structures on membrane separation performance and CO2 separation mechanism were emphatically analyzed and concluded. The challenges and prospective of IL-based membranes for CO2 separation are presented.

Ionic Liquid–Based Membranes for CO2 Separation

Coal-tar pitch (CP) is a promising carbon raw material for producing needle coke, carbon fiber etc. During processing, the H/C ratio, ash content, and quinoline insoluble (QI) in the CP are the key factors that influence the material preparation. In this study, NMP was selected to extract CP first; then [BMIM]Cl/NMP mixed solvent was used; and finally a series of ionic liquids (ILs) mixtures with NMP were developed for the extraction of CP to obtain the refined pitch. The extracts were analyzed via elemental analysis, TGA, FT-IR, and 13C-NMR. Results indicate that different NMP/IL mass ratios or different kinds of ILs have impact on the extraction yield. The relationship of the hydrogen to carbon (H/C) ratio changed with different solvents and QI extracts were obtained. Results showed that the H/C ratios changed little between NMP extracts and could be adjusted by changing the NMP/ILs mass ratio or using different ILs. The extracts are suitable for preparation mesophase pitch because of no ash content, low QI, and appropriate H/C ratios. As a result, NMP can be used to refine pitch. In addition, [BMIM]Cl is good mixed with NMP for CP extraction, because it can obtain a relatively high yield under the same extraction conditions.

Extraction of coal-tar pitch using NMP/ILs mixed solvents

Exploring NH3 Transport Properties by Tailoring Ionic Liquids in Pebax-Based Hybrid Membranes

Ethyl acetate (EA) is a widely used solvent and raw material in chemical and pharmaceutical industries. The removal of the low water content (<2%) in EA is difficult using the conventional separati...

Highly Efficient Dehydration of Ethyl Acetate using Strong Hydrophilic Ionic Liquids

The invention relates to a method for preparing a cellulose-based carbon fiber or carbon film from an ionic liquid. The ionic liquid is used as a solvent to efficiently dissolve cellulose and dispersea carbon nanomaterial, and an ionic liquid-cellulose-carbon nanocomposite solution is obtained; a conductive fiber or a conductive film is prepared from the composite solution by spinning or wiping;the cellulose-based carbon fiber or carbon film with high conductivity is further prepared by preoxidation and carbonization treatment. The method is simple in process, cellulose is abundantly sourcedand cheap, an ionic liquid is environmentally friendly and recoverable, a carbon nanotube, graphene and conductive carbon black are added to a cellulose matrix, conductivity of the carbon fiber or the carbon film is greatly improved, and the carbon fiber or the carbon film can be applied to the fields of antistatic textiles, electric heating garments, electromagnetic shielding fabrics and the like and has wide application prospect.

Lu Bai

Papers

Ionic Liquid–Based Membranes for CO2 Separation

Extraction of coal-tar pitch using NMP/ILs mixed solvents

Exploring NH3 Transport Properties by Tailoring Ionic Liquids in Pebax-Based Hybrid Membranes

Highly Efficient Dehydration of Ethyl Acetate using Strong Hydrophilic Ionic Liquids

Method for preparing cellulose-based carbon fiber or carbon film from ionic liquid