Comparison of the a Priori COSMO-RS Models and Group Contribution Methods: Original UNIFAC, Modified UNIFAC(Do), and Modified UNIFAC(Do) Consortium

A comparison of the performances of the COSMO-SAC, COSMO-RS­(Ol), original UNIFAC, modified UNIFAC­(Do), and modified UNIFAC­(Do) Consortium for activity coefficients at infinite dilution and binary VLE data is presented. The σ-profiles used in performing COSMO-SAC and COSMO-RS­(Ol) calculations were taken from the published σ-profile database VT 2005. The predicted results were compared with the experimental data stored in the Dortmund Data Bank and analyzed with respect to the types of components in the mixture. The results show that the UNIFAC models based on experimental data are superior to the a priori COSMO-RS models

An Environmentally Benign Cycle To Regenerate Chitosan and Capture Carbon Dioxide by Ionic Liquids

A new cycle platform has been built to provide an efficient method for biomass utilization and greenhouse gas control simultaneously via the interplay of interactions between ionic liquids (ILs), chitosan, and CO₂. All samples, including chitosan/IL solutions, chitin/IL solutions, and pure ILs, were employed to perform experiments on CO₂ capture/release. The results indicated that chitosan with a high degree of deacetylation can capture CO₂ in a nearly 2:1 stoichiometry. In the meantime, different mechanisms of chitosan regeneration from acetate-based ILs and others were explored. For the acetate-based ILs, ¹H and ¹³C NMR spectroscopy implied the formation of new species of [imida⁺–COO^–] after the chemical CO₂ capture, while only the changes of volume expansion and solvatochromic UV–vis parameters can give rise to chitosan regeneration for the ILs with less basic anions. In addition, raw chitosan was used to demonstrate the cycle by selective capture of CO₂ and precipitation from [Bmim]­OAc using compressed CO₂

Biomass-Derived γ‑Valerolactone-Based Solvent Systems for Highly Efficient Dissolution of Various Lignins: Dissolution Behavior and Mechanism Study

Binary solvent systems consisting of biomass-derived γ-valerolactone (GVL) and one cosolvent (e.g., water, ionic liquids, DMSO, and DMF) were developed as highly efficient systems for dissolution of various types of lignin. It was found that the content of cosolvent in GVL significantly affected the solubility of lignins. More importantly, we first concluded that the relationship between the solubility of lignin and hydrogen bond basicity parameter β value of solvents depends both on the solvent and on the lignin, which clarifies the existing dispute on this topic. Additionally, the dissolved lignin can be easily recovered by the addition of ethanol without its structure noticeably changing. The as-proposed systems are not only mild and highly efficient but also versatile and flexible (with different components and concentrations), thus adapting to the highly diversity of lignin

Water Sorption in Functionalized Ionic Liquids: Kinetics and Intermolecular Interactions

The water sorption by nine functionalized imidazolium based ionic liquids (ILs) with the effects of temperature and relative humidity were investigated. Three kinds of parameters (sorption capacity, sorption rate, and sorption equilibrium) were derived to comprehensively characterize the sorption processes. A sorption triangle was proposed to correlate these kinds of parameters, which were the corresponding three vertices of this triangle. The sorption triangle has three effective categories numbered types 1, 2, and 3. The hydrophilicity of the ILs was sorted into four levels according to the steady-state water sorption capacity. The sorption results were consistent with the water–IL interaction investigation with attenuated total refletance infrared (ATR-IR) and nuclear magnetic resonance (NMR) spectra. The functionalized ILs investigated in this study are more hydrophilic than conventional ILs from a statistical view

Efficient and Sustainable Strategy for the Hierarchical Separation of Lignin-Based Compounds Using Ionic Liquid/Compressed CO₂

Lignin has received increasing attention as a potential starting material for providing valuable low-molecular-weight aromatic compounds. Herein, a strategy for lignin degradation and low-molecular-weight compound hierarchical separation is presented. Ionic liquid and compressed CO₂ were used in the two-step protocol. 1-Butyl-3-methylimidazolium acetate was used to induce the cleavage of C–O and C–C linkage as well as dehydration reaction of lignin at high temperatures, especially combined with sonication assistance. The low-molecular-weight aromatic compounds from lignin can be followed to separate efficiently and hierarchically by adjusting the pressure of compressed CO₂. The size distribution and chemical structure of lignin samples were investigated to explain the mechanism, indicating that our method is easy and efficient

Ionic Liquid as Reaction Medium for Synthesis of Hierarchically Structured One-Dimensional MoO₂ for Efficient Hydrogen Evolution

Hierarchically structured one-dimensional (1D) MoO₂ is synthesized for the first time in ionic liquid 1-butyl-3-methylimidazolium bis­(trifluoromethanesulfonyl)­imide ([BMIM]­[Tf₂N]). The synthesis system is very simple (single [BMIM]­[Tf₂N] solvent plus MoO₂(acac)₂ reactant). [BMIM]­[Tf₂N] itself works as both the reaction medium and the template for the formation of these interesting 1D MoO₂ particles with ultrathin nanosheet subunits. The as-synthesized hierarchically 1D MoO₂_₄₀ particles exhibit remarkable electrocatalytic activity with good long-term cycle stability for the hydrogen evolution reaction (HER) in acidic media. The HER activity of present synthesized MoO₂ is comparable to those of the most active Mo-based electrocatalysts in acid media reported up to now. Therefore, the ionic liquid route provides us with a newly powerful tool for the synthesis of interesting alternative to noble metal catalysts for efficient electrocatalytic production of hydrogen in acidic environment

Preparation and Properties of CX (X: O, N, S) Based Distillable Ionic Liquids and Their Application for Rare Earth Separation

The negligible vapor pressure of ionic liquids prevents the separation of ionic liquids from other nonvolatile substances by distillation. Most distillable ionic liquids have been reported are protic ionic liquids, and the aprotic ionic liquids are still scarce. In this work, we designed and synthesized a series of unsaturated bond (CX; X is O, N, S) based ionic liquids and some of them could be distilled at a mild condition. Moreover, [MDMF]­TfO shows a high efficiency for separation of EuCl₃ from the mixture of EuCl₃ and NdCl₃

Gadolinium-Based Metal–Organic Framework as an Efficient and Heterogeneous Catalyst To Activate Epoxides for Cycloaddition of CO₂ and Alcoholysis

Development of heterogeneous catalysts for the cycloaddition of CO₂ with epoxides to prepare cyclic carbonates is a hot topic in the field of CO₂ transformation. Herein, a rare-earth-metal gadolinium-based metal–organic framework (Gd-MOF) was synthesized from GdCl₃ and pyromellitic dianhydride in <i>N,N</i>-dimethylformamide, which was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption–desorption, and Fourier transform infrared (FT-IR) spectroscopy. The synthesized Gd-MOF could be used as heterogeneous catalyst for the cycloaddition of CO₂ with epoxides in the presence of quaternary ammonium salts, and Gd-MOF/<i>n</i>-Bu₄NBr showed the best performance for the cycloaddition of CO₂ with various epoxides to form the corresponding cyclic carbonates due to the excellent synergetic effect. Furthermore, the prepared Gd-MOF could be used as heterogeneous catalyst for alcoholysis of various epoxides to form β-alkoxy alcohols effectively

Kamlet–Taft Parameters of Deep Eutectic Solvents and Their Relationship with Dissolution of Main Lignocellulosic Components

Deep eutectic solvents (DESs) have attracted significant interest in dissolving lignocellulosic components. However, revealing the relationship between the solvation properties of DESs and their ability to dissolve lignocellulosic components remains a significant challenge. Herein, 56 DESs were prepared and applied to dissolve lignocellulosic components. This revealed that the Kamlet–Taft parameters (i.e., α, β, and π*) were significantly affected by the structures of DESs. More notably, the correlation between Kamlet–Taft parameters and solubility varied with DESs and lignocellulosic components. Concretely, DESs have greater values of β and β–α (net basicity), are expected to dissolve cellulose efficiently, have greater net basicity, and are favorable to dissolve lignin, and the solubility of xylan was linearly correlated with the β value. These findings provided valuable information and necessary theoretical guidance on designing robust DESs to dissolve lignocellulosic components based on Kamlet–Taft solvatochromic parameters

Large-Scale, Highly Efficient, and Green Liquid-Exfoliation of Black Phosphorus in Ionic Liquids

We developed a facile, large-scale, and environmentally friendly liquid-exfoliation method to produce stable and high-concentration dispersions of mono- to few-layer black phosphorus (BP) nanosheets from bulk BP using nine ionic liquids. The prepared suspensions can stabilize without any obvious sedimentation and aggregation in ambient air for one month. In particular, the concentration (up to 0.95 mg mL^–1) of BP nanoflakes obtained in 1-hydroxyethyl-3-methylimidazolium trifluoromethansulfonate ([HOEMIM]­[TfO]) is the highest reported for BP nanosheets dispersions. This work provides new opportunities for preparing atomically thin BP nanosheets in green, large-scale, and highly concentrated processes and achieving its in situ application