Supported Ionic Liquids Research Articles

Copolymerization of ethylene with norbornene or 1-octene using supported ionic liquid systems

Copolymerization of ethylene with norbornene (E/NB) and ethylene with 1-octene (E/Oct) is performed using supported ionic liquid (SIL) systems, in which metallocene (Cp2VCl2) or post-metallocene [VCl2(salenCl2)] vanadium catalysts are immobilized in pyridinium chloroaluminate ionic liquid supported on silica. The studied SIL catalysts show higher activities as well as stability than their non-supported analogues. In addition, higher activities and better comonomer incorporation are observed for norbornene (above 30 mol%). The comonomer incorporation has considerable influence on copolymer molecular weight (Mw), melting temperature, crystallinity degree, and microstructure of the copolymers. Molecular-weight distribution is relatively narrow (1.5 ≤ Mw/Mn ≤ 3.0), which indicates the presence of single-site catalyst systems.

Study on the esterification for ethylene glycol diacetate using supported ionic liquids as catalyst: Catalysts preparation, characterization, and reaction kinetics, process

Three supported ionic liquids (SILs) were synthesized and characterized. And the catalytic activity for the preparation of ethylene glycol diacetate (EGDA) via the esterification of ethylene glycol (EG) and acetic acid were studied. Among them, [Silica-Ps-im]HSO4 performed best and was chosen as catalyst for further study. The reaction kinetics experiments were carried out to correlate the parameters in a pseudo-homogeneous second order kinetic model. It has been found that there is good agreement between the calculated values and experimental data. In order to enhance the conversion of EG and yield of EGDA, a batch reactive distillation experimental apparatus was set up. A high conversion of EG of 100% and yield of EGDA of 99.14% were obtained under the optimal reaction conditions. The reusability test shows that [Silica-Ps-im]HSO4 catalyst has excellent utility for repeated use, the ease of its isolation from reaction mixture by simple filtration is beneficial from an economical point of view.

Metallocenes and post-metallocenes immobilized on ionic liquid-modified silica as catalysts for polymerization of ethylene

The supported ionic liquid (SIL) strategy was used for the first time to metallocene and post-metallocene heterogeneous catalysts for olefin polymerization. The metal complexes: Cp2TiCl2, Cp2ZrCl2, FI–Ti, and Sal–Ti were immobilized in the 1-(3-triethoxysilyl)propyl-3-methylimidazolium alkylchloroaluminate ionic liquid, anchored on the surface of the mesoporous amorphous silica. The SIL systems were characterized by FTIR, 29Si NMR, N2 adsorption, EA, AAS, TG, and SEM techniques. The developed supported catalytic systems were found to be active in the ethylene polymerization and produce the polyethylene of various properties.

Imidazolium-based ionic liquids grafted on solid surfaces.

Supported ionic liquids (SILs), which refer to ionic liquids (ILs) immobilized on supports, are among the most important derivatives of ILs. The immobilization process of ILs can transfer their desired properties to substrates. Combination of the advantages of ILs with those of support materials will derive novel performances while retaining properties of both moieties. SILs have been widely applied in almost all of fields involving ILs, and have brought about drastic expansion of the ionic liquid area. As green media in organic catalytic reactions, based on utilizing the ability of ILs to stabilize the catalysts, they have many advantages over free ILs, including avoiding the leaching of ILs, reducing their amount, and improving the recoverability and reusability of both themselves and catalysts. This has critical significance from both environmental and economical points of view. As novel functional materials in surface science and material chemistry, SILs are ideal surface modifying agents. They can modify and improve the properties of solids, such as wettability, lubricating property, separation efficiency and electrochemical response. With the achievements in the field of ILs, using magnetic nanoparticles (MNPs) to SILs has drawn increasing attention in catalytic reactions and separation technologies, and achieved substantial progress. The combination of MNPs and ILs renders magnetic SILs, which exhibit the unique properties of ILs as well as facile separation by an external magnetic field. In this article, we focus on imidazolium-based ILs covalently grafted to non-porous and porous inorganic materials. The excellent stability and durability of this kind of SILs offer a great advantage compared with free ILs and IL films physically adsorbed on substrates without covalent bonds. Including examples from our own research, we overview mainly the applications and achievements of covalent-linked SILs in catalytic reactions, surface modification, separation technologies and electrochemistry.

MOR zeolite supported Brønsted acidic ionic liquid: an efficient and recyclable heterogeneous catalyst for ketalization

In order to widen the application of ionic liquids as efficient and renewable heterogeneous catalysts, supported ionic liquids (SILs) have received considerable attention.

Adsorption of bromophenol blue from aqueous samples by novel supported ionic liquids

AbstractBACKGROUNDDyeing industry effluent is one of the most problematic waste waters needing to be treated. New adsorption materials, supported ionic liquids (SILs), have been successfully applied for dyes separation.RESULTSIn this study, five SILs including two novel SILs were prepared and characterized by Fourier transform infrared spectroscopy (FT‐IR), elemental analysis, thermogravimetric analysis (TG‐DTA) and nitrogen adsorption–desorption isotherms. The new benzothiazolium hexafluorophosphate‐supported silica (SiO2·Bth+·PF6−) was screened out as the most effective adsorbent for adsorption of bromophenol blue (BPB), and had excellent adsorption and desorption capacity in dynamic adsorption and desorption experiments. It could be reused easily after elution with 0.01 mol L‐1 NaOH. Studies showed that the kinetic data were well described by the pseudo‐second‐order kinetic model. Moreover, the isotherm experiments revealed that the Langmuir model yielded better fitting than the Freundlich model for BPB adsorption. The calculated thermodynamic parameters indicated that the adsorption of BPB was spontaneous and endothermic.CONCLUSIONFive SILs including two novel SILs were prepared and characterized, and their application in the adsorption of BPB was investigated in detail. Among them, SiO2·Bth+·PF6− was found to be the best. This study is expected to be helpful in expanding the type of SILs and their application in the treatment of dyes pollution.© 2013 Society of Chemical Industry

ChemInform Abstract: The Preparation of Supported Ionic Liquids (SILs) and Their Application in Rare Metals Separation

AbstractReview: 58 refs.

Immobilizing Penicillin G Acylase Using Silica-Supported Ionic Liquids: The Effects of Ionic Liquid Loadings

The supported ionic liquids (SILs) were prepared via immobilizing silane-functionalized ionic liquids (IL) onto the monodispersive silica nanoparticles, and the composite material was then applied in the immobilization of penicillin G acylase (PGA, EC 3.5.1.11), an important industrial enzyme for the production of semisynthetic antibiotics. This was a novel approach of immobilizing PGA proposed in our previous report, in which we had studied the effects of IL types on the performance of this novel support. Here, we focused on the effects of IL loading on the properties of the SILs and their performance in PGA immobilization. The effects of silica sizes and routes of preparing SILs (the solvent route and the sol–gel route) on IL loading were investigated. The results showed that (1) the IL loading could be tuned efficiently by changing the silica sizes. (2) As compared with the solvent route, the sol–gel route is more simple, time-saving, and ecofriendly in operation. What's more, it has a higher IL loading. Among the factors affecting the IL loading, the reaction time was the most feasible factor to control to tune the IL loading, as compared with the temperature and the dosage of ILs. (3) With the increase of IL loading, the surface ζ-potential of silicas changed from negative to positive, and the isoelectronic point (IEP) increased accordingly, which caused the decrease of the protein loading but the increase of apparent and specific activity. A reusability experiment showed that the sol–gel 1 sample maintained approximately 55% of the initial activity even after 10 consecutive operation cycles under the experimental conditions. This activity was 3.7 times higher than that of the sol–gel 2 sample.

The preparation of supported ionic liquids (SILs) and their application in rare metals separation

This review summarizes the preparation methods of support ionic liquids (SILs) and their applications in rare metals separation. The rare metals separation includes the recovery of high value metal ions and the removal of heavy metal ions from wastewater. SILs can be used as a kind of highly efficient multifunctional separation materials. The preparation methods of SILs include chemical immobilization technique in which ILs moieties are supported on solid supports via covalent bonds and physical immobilization techniques in which ILs are immobilized on solid supports via physical method such as simple impregnation, sol-gel method. According to the difference of solid supports, this review summarizes the application of polymer supported ionic liquids (P-SILs), silica based material supported ionic liquids (SM-SILs) and membrane supported ionic liquids (M-SILs) in rare metals separation. P-SILs and SM-SILs prepared by chemical method with N-methylimidazolium group can be used as highly efficient anion exchangers with high thermal stability and good chemical stability for adsorption of Cr(VI), Re(VII), Ce(IV). P-SILs prepared via simple impregnation afforded IL functionalized solvent impregnated resins (SIRs) which showed high separation efficiency and selectivity in the separation of rare earths(III) (REs(III)). SM-SILs prepared via sol-gel method with IL doped in the support as porogens or extractant show high removal efficiencies and excellent stability for the separation of RE(III), Cr(III) and Cr(VI). M-SILs with IL as plasticizer or carrier show improved stability, high permeability coefficient and good selectivity for Cr(VI) transport. Different supports and different supporting methods were sufficiently compared. Based on the different practical application, different forms of SILs can be prepared for separation of rare metals with high separation efficiency and selectivity.

Research on the adsorption property of supported ionic liquids for ferulic acid, caffeic acid and salicylic acid

In this paper, the preparation of new supported ionic liquids (SILs) composed of the N-methylimidazolium cation and the quinoline cation is described. They have been confirmed and evaluated by infrared spectroscopy, elemental analysis and thermogravimetric analysis. Six kinds of different SILs included SiO 2·Im +·Cl −, SiO 2·Im +·BF 4 −, SiO 2·Im +·PF 6 −, SiO 2·Qu +·Cl −, SiO 2·Qu +·BF 4 − and SiO 2·Qu +·PF 6 −. The adsorption characteristics of ferulic acid (FA), caffeic acid (CA) and salicylic acid (SA) on SILs were investigated by static adsorption experiments. It was found that SiO 2·Qu +·Cl − had excellent adsorption and desorption capacity to three tested phenolic compounds. The dynamic adsorption characteristics of FA, CA and SA on SiO 2·Qu +·Cl − were also studied. The saturated adsorption capacity of FA, CA and SA using SiO 2·Qu +·Cl − as adsorbent was 64.6 mg/g, 53.2 mg/g and 72.2 mg/g respectively. Using 70% ethanol as eluent, the saturated desorption efficiencies of FA, CA and SA were 97.2%, 90.3% and 96.5% respectively. Thus, SiO 2·Qu +·Cl − had strong adsorption and separation capacity for FA, CA and SA.