An environmentally friendly hydroformylation using carbon dioxide as a reactant catalyzed by immobilized Ru-complex in ionic liquids

The compatibility of the mixed electrolyte of two ionic liquids based on 1,3-substituted imidazolium cations with lithium manganese oxide LiMn2O4, lithium iron phouphate LiFePO4, graphite, and a hard carbon has been confirmed. For LiMn2O4 and LiFePO4, the mixed imidazolium ionic liquid electrolyte provides slightly higher plateau in discharge curves, while the initial capacity is slightly lower, when compared with piperidinium ionic liquid. In case of LiMn2O4, the capacity in the mixed ionic liquid is recovered by subsequent cycling. The thermal stabilities of charged positive electrodes with the mixed ionic liquid, as well as with the piperidinium one, from accelerating rate calorimetry are far over those in conventional carbonate electrolyte. A hard carbon electrode is compatible with the mixed ionic liquid electrolyte.

Review: 33 refs.

Molecular interactions are crucial between the enzyme molecules and the surrounding solution in an enzymatic catalysis. Although aqueous solutions used as conventional enzymatic reaction media, non-aqueous enzymology emerges as a major area of biotechnology research and development. Ionic liquids, as new generation of promising alternatives to traditional organic solvents, possess potential industrial enzymatic applications. Enzymes in ionic liquids present enhanced activity, stability, and selectivity. In addition, the potential of ionic liquids in bio-catalysis is raised by high ability of dissolving a wide variety of substrates and their extensively tunable solvent properties through appropriate modification of the cations and anions. However, despite the bio-friendly nature of ionic liquids for enzymatic reactions, their growing interests increase concerns associated with toxicity and environmental pollution of such compounds. This mini-review presents a brief highlight of the contemporary knowledge of enzymes activity and stability in ionic liquids and the environmental influences regarding the potential risks related to the growing applications of these green solvents. HIGHLIGHTS •Conventional organic solvents can be replaced by ionic liquids as green solvents. •Ionic liquids are used as additives, catalysts, or reaction media in industries. •Advantages and disadvantages of ionic liquids are discussed. •Potential environmental hazards linked to application of ionic liquids are highlighted. •The environmental fate needs to be considered in designing safer ionic liquids.

Cytocompatible drug delivery devices based on poly[(2-dimethylamino) ethyl methacrylate]/chondroitin sulfate polyelectrolyte complexes prepared in ionic liquids

In this study, a new class of polymerizable ionic liquids were synthesized and modified upon conductive surfaces to enhance the sensitivity and/or selectivity of the electrodes, or to be electrochromic films. At suitable conditions, the poly-ionic liquids were soluble in some organic solvents. Ionic liquids (ILs) have shown the advantages on electroanalysis when they were modified on electrode surface. Electropolymerization might be a good approach for the modification of ILs on conductive surface. Various carbazole-based ILs (Figure 1) were synthesized in this study and they were electropolymerized on indium tin oxide (ITO) electrodes by cyclic voltammetry in ILs BMP-TFSI, BMIm-PF6 and etc., as well as in conventional solvents (i.e. acetonitrile, methanol and DMSO)[1]. Electrochemical oxidation of the carbazole pendant units affords a conjugated polymer network (CPN) film of polycarbazole and the polymer is expected to have good conductivity on the conducting surface[2]. The electrode with electropolymerized ILs shows improved activity towards the oxidation of uric acid (UA), compared with that of unmodified electrodes. The polymerized ILs also exhibit electrochromic properties. The ITO electrodes modified with polycarbazole ILs show color change from deep green to pale yellow while the applied potential was scanned from +1.2 V to -0.2 V and vice versa. On the other hand, bipyridinium (viologen) ionic liquids modified with carbazole via an alkyl spacer were synthesized and their electrochromic behavior in liquid state was studied in various ILs or conventional volatile organic solvents. Viologen is a well-known electroactive material with three different redox states: the dication, the radical cation and the neutral compound. The colors of radical cations depend on the groups substituted on the nitrogen atoms of the viologen moiety[3]. By introducing the carbazole groups, colors different from those observed for the traditional viologen compounds were recorded. This behavior is currently studied. [1] D.-X. Zhuang, P.-Y. Chen, Journal of Electroanalytical Chemistry, 2009, 626: 197–200. [2] Antonio F. Frau, Nicel C. Estillore and Rigoberto C. Advincula,ACS Appl. Mater. Interfaces, 2010, 2: 3726–3737. [3] N. Jordao, L. Cabrita, F. Pina and L.C. Branco, Chem.-Eur.J., 2014, 20: 3982–3988. Figure 1

During past few years, ionic liquids have kept attracting much attention as “green and designer” media for chemical reactions. Room-temperature ionic liquids have emerged as a potential replacement for organic solvents in catalytic processes on both laboratory and industrial scales (Holbrey & Seddon, 1999b). Literature reports on a wide range of reactions including advances in alkylation reactions (Earle et al., 1998), Diels-Alder cyclizations (Earle et al., 1999; Jaeger & Tucker, 1989), and the development of commercially competitive processes for dimerization, oligomerization, and polymerization of olefins (Abdul-Sada et al., 1995a; 1995b; Ambler et al., 1996; Chauvin et al., 1988; 1989). Effectively, Ionic liquids, among a unique set of chemical and physical properties (Chauvin, 1996; Chauvin & Mussmann 1995; Seddon, 1997), have no measurable vapor pressure, which lends them as ideal replacements for volatile, conventional organic solvents. The wide and readily accessible range of room-temperature ionic liquids with corresponding variations in physical properties, prepared by simple structural modifications to the cations (Gordon et al., 1998; Holbrey & Seddon, 1999a) or changes in anions (Bonhoˆte et al., 1996; Wilkes & Zaworotko, 1992), offers the opportunity to design an ionic liquid-solvent system optimized for particular processes. In other words, these ionic liquids can be considered as “designer solvents” (Freemantle, 1998). Applications of ionic liquids as solvents for polymerization processes have widely been reviewed in literature (Kubisa, 2004; Shen & Ding, 2004; Lua et al., 2009). Ionic liquids have been used in polymer science, mainly as polymerization media in several types of polymerization processes, including conventional free radical polymerization (Sarbu, & Matyjaszewski, 2001), living/controlling radical polymerizations (such as atomtransfer radical polymerizations (ATRP) (Ding et al., 2005; Shen & Ding., 2004; Biedron & Kubisa., 2001; Biedron & Kubisa., 2002; Biedron & Kubisa., 2003), reversible addition-ragmentation transfer (RAFT) (Perrier & Davis, 2002), as well as in ionic and coordination polymerizations (Chiefari et al., 1998; Vijayaraghavan & MacFarlane et al., 2004). When radical polymerizations are conducted in an ionic liquid, a significant increase of kp/kt ratio is normally observed in comparison to those carried out in other polar/coordinating solvents. As solvents for ATRP and RAFT, ionic liquids facilitate separation of the polymer from residual catalyst and reduce the extent of side-reactions.

Development in the green synthesis of cyclic carbonate from carbon dioxide using ionic liquids

For Abstract see ChemInform Abstract in Full Text.

Introduction Ionic liquids can be used as a medium in which perform catalytic reactions and the system recovered and reused in multiple runs (1-6). The necessary condition for this reuse is that the catalyst should remain unaltered in the ionic liquid while the reaction mixture is separated from the ionic melt by precipitation, distillation, extraction or any other physical mean. The combination of catalysis and ionic liquids derives from the principles of green chemistry that aim to accomplish waste minimization, atom economy and the avoidance of volatile organic solvents (7, 8). Ionic liquids are considered greener than conventional organic solvents due to their low vapor pressure, no flammability and the possibility to devise procedures for catalyst reuse. As some other groups (9-18), our work in ionic liquids has been focused on the transformation of successful transition metal catalysts in conventional organic solvents into recoverable and reusable (homogeneous or heterogeneous) catalytic

Biocatalytic reactions in hydrophobic ionic liquids

This study investigates the process and economic impacts of using an aqueous mixture of 1‐butylpyridinium tetrafluoroborate ([Bpy][BF4]) ionic liquid (IL) and monoethanolamine (MEA) as the solvent for CO2 capture from a coke‐oven plant. The gaps highlighted in the literature on the study of an aqueous mixture of IL and MEA for CO2 capture include lack of detailed process models or information on the impacts of varying the IL concentration on different process conditions and economics. This study addressed these needs by developing a rate‐based, solvent‐based CO2 capture process model with a mixed IL and MEA solvent and using the model to perform process and economic evaluations. The model was developed with Aspen Plus® and was used to investigate seven different aqueous mixtures of IL and MEA. The MEA concentration was 30 wt% for all the seven aqueous solvent mixtures, and the corresponding IL concentration was 0, 5, 10, 15, 20, 25 and 30 wt% for each combination. The hybrid IL solvent mixtures (i.e. 5–30 wt% IL) have 7–9% and 12–27% less regeneration energy and solvent circulation rate respectively compared to the base case (i.e. 30 wt% MEA). Based on a commercial‐scale cost benchmark for the IL, the initial solvent cost for the mixed solution is predictably higher. However, the solvent makeup cost is less for the mixed solvent. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

As environmentally benign "green" solvents, room temperature ionic liquids (ILs) have been used as solvents or (co)solvents in biocatalytic reactions and processes for a decade. The technological utility of enzymes can be enhanced greatly by their use in ionic liquids (ILs) rather than in conventional organic solvents or in their natural aqueous reaction media. In fact, the combination of green properties and unique tailor-made physicochemical properties make ILs excellent non-aqueous solvents for enzymatic catalysis with numerous advantages over other solvents, including high conversion rates, high selectivity, better enzyme stability, as well as better recoverability and recyclability. However, in many cases, particularly in hydrophilic ILs, enzymes show relative instability and/or lower activity compared with conventional solvents. To improve the enzyme activity as well as stability in ILs, various attempts have been made by modifying the form of the enzymes. Examples are enzyme immobilization onto support materials via adsorption or multipoint attachment, lyophilization in the presence of stabilizing agents, chemical modification with stabilizing agents, formation of cross-linked enzyme aggregates, pretreatment with polar organic solvents or enzymes combined with suitable surfactants to form microemulsions. The use of these enzyme preparations in ILs can dramatically increase the solvent tolerance, enhance activity as well as stability, and improve enantioselectivity. This perspective highlights a number of pronounced strategies being used successfully for activation and stabilization of enzymes in non-aqueous ILs media. This review is not intended to be comprehensive, but rather to present a general overview of the potential approaches to activate enzymes for diverse enzymatic processes and biotransformations in ILs.

Some organic solvents are highly toxic, flammable, and even explosive. In particular, high vapor pressures and toxicity of certain volatile organic solvents may cause significant environmental problems. Therefore, alternative solvents or media with tunable and versatile solvation properties for conducting chemical reactions and materials synthesis have been actively sought. Ionic liquids have numerous applications not only as environmentally benign reaction media, but also as catalysts and reagents. Due to the increase of environmental consciousness in chemical research and industry, the challenge for a sustainable environment calls for clean procedures that avoid the use of harmful organic solvents. Due to the special properties of ILs (ionic liquids) such as wide liquid range, good solvating ability, negligible vapor pressure, non-inflammability, non-volatility, environment friendly medium, high thermal stability, good stability in air and moisture, easy recycling and rate promoters etc. they are used in organic synthesis. Therefore, ionic liquids have attracted the attention of chemists and act as catalyst and reaction medium in organic reactions with high activity. Highly efficient methods are explored for the preparation of S-heterocycles with the application of ILs as catalyst and reaction medium.

Chitosan/iota-carrageenan/curcumin-based materials performed by precipitating miscible solutions prepared in ionic liquid

Switchable hydrophilicity solvents for lipid extraction from microalgae for biofuel production