143314-17-4Relevant articles and documents
Induction of lignin solubility for a series of polar ionic liquids by the addition of a small amount of water
Akiba, Takashi,Tsurumaki, Akiko,Ohno, Hiroyuki
, p. 2260 - 2265 (2017)
Addition of a small amount of water was found to induce the lignin solubilizing ability in several polar ionic liquids which showed no lignin solubility in the absence of water. Similarly, addition of water was found to enhance lignin solubility in many polar ionic liquids. Though addition of water lowered the proton accepting ability of these ionic liquids, their proton donating ability was found to increase. The lignin dissolution by ionic liquids was newly found to be a function of both the proton accepting ability and proton donating ability of the ionic liquids. Water is a poor solvent for polysaccharides, and water addition has therefore been confirmed to be effective to improve the selective extraction yield of lignin from cedar powder under mild conditions.
A novel and simple procedure to synthesize chitosan-graft-polycaprolactone in an ionic liquid
Wang, Zhaodong,Zheng, Liuchun,Li, Chuncheng,Zhang, Dong,Xiao, Yaonan,Guan, Guohu,Zhu, Wenxiang
, p. 505 - 510 (2013)
An ionic liquid, 1-ethyl-3-methylimidazolium acetate (EMIMAc), was synthesized and employed as a homogeneous and green reaction media to prepare chitosan-graft-polycaprolactone (CS-g-PCL) via ring-opening polymerization, using stannous octoate (Sn(Oct)2) as a catalyst. The structures and compositions of copolymers could be facilely controlled by the reaction conditions and feed ratios. The grafting content of polycaprolactone (PCL) could reach as high as 630%. The chemical structures of the copolymers were systematically characterized by 1H NMR, Fourier transform infrared spectroscopy (FTIR) and wide-Angle X-ray diffraction (WAXD), while thermal properties were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The thermal stability and glass transition temperature (Tg) of the graft copolymers vary regularly with the change of PCL grafting content.
Catalytic conversion of cellulose to 5-hydroxymethyl furfural using acidic ionic liquids and co-catalyst
Ding, Zhen-Dong,Shi, Jin-Cai,Xiao, Jing-Jing,Gu, Wen-Xiu,Zheng, Chang-Ge,Wang, Hai-Jun
, p. 792 - 798 (2012)
Efficient catalytic conversion of microcrystalline cellulose (MCC) to 5-hydroxymethyl furfural (HMF), is achieved using acidic ionic liquids (ILs) as the catalysts and metal salts as co-catalysts in the solvent of 1-ethyl-3-methylimidazo-lium acetate ([emim][Ac]). A series of acidic ILs has been synthesized and tested in conversion of MCC to HMF. The effect of reaction conditions, such as reaction time, temperature, catalyst dosage, metal salts, water dosage, Cu2+ concentration and various acidic ILs are investigated in detail. The results show that CuCl2 in 1-(4-sulfonic acid) butyl-3-methylimidazolium methyl sulfate ([C4SO 3Hmim][CH3SO3]), is found to be an efficient catalyst for catalytic conversion of MCC to HMF, and 69.7% yield of HMF is obtained. A mechanism to explain the high activity of CuCl2 in [C4SO3Hmim][CH3SO3] is proposed. To the best of our knowledge, this report first proposes that the Cu2+ and [C4SO3Hmim][CH3SO3] show better catalytic performance in catalytic conversion of MCC to HMF.
Halogen-free ionic liquids and their utilization as cellulose solvents
Gr?svik, John,Eliasson, Bertil,Mikkola, Jyri-Pekka
, p. 156 - 163 (2012)
This work demonstrates a novel synthesis route to halogen-free ionic liquids. A one-pot synthetic reaction route avoiding the use of toxic and high-energetic alkyl halides was developed to reduce the environmental impact of the synthesis process of ionic liquids. However, the elimination of halogens and alkyl halides in the preparation of ionic liquids is not just an environmental issue: the aforementioned species are also among the most common and persistent contaminants in today's Ionic Liquids (ILs). Thus, this paper introduces a range of quaternized nitrogen based ionic liquids, including both aromatic and non-aromatic components, all prepared without alkyl halides in any step of the process. Moreover, bio-renewable precursors such as (bio-)alcohols and carboxylic acids were employed as anion sources and alkylation media, thus avoiding halogen contamination or halogen-containing anions. The IL's prepared were designed to dissolve cellulose, some of which was included in a cellulose dissolution study using a sulphite cellulose from the company Domsj?.
Ionic parachor and its application in acetic acid ionic liquid homologue 1-alkyl-3-methylimidazolium acetate {[Cnmim][OAc](n = 2,3,4,5,6)}
Guan, Wei,Ma, Xiao-Xue,Li, Long,Tong, Jing,Fang, Da-Wei,Yang, Jia-Zhen
, p. 12915 - 12920 (2011)
Five acetic acid ionic liquids (AcAILs) [Cnmim][OAc](n = 2,3,4,5,6) (1-alkyl-3-methylimidazolium acetate) were prepared by the neutralization method and characterized by 1HNMR spectroscopy and differential scanning calorimetry (DSC). The values of their density and surface tension were measured at 298.15 ± 0.05 K. Since the AcAILs can strongly form hydrogen bonds with water, the small amounts of water are difficult to remove from the AcAILs by common methods. In order to eliminate the effect of the trace water, the standard addition method (SAM) was applied to these measurements. As a new concept, ionic parachor was put forward. [OAc] - was seen as a reference ion, and its individual value of ionic parachor was determined in terms of two extrathermodynamic assumptions. Then, the values of ionic parachors of a number of anions, [NTf2] -, [Ala]-, [AlCl4]-, and [GaCl 4]-, were obtained by using the value of the ionic parachor of the reference ion; the parachor and surface tension of the investigated ionic liquids in literature were estimated. In comparison, the estimated values correlate quite well with their matching experimental values.
Simple and recyclable ionic liquid based system for the selective decomposition of formic acid to hydrogen and carbon dioxide
Berger,Assenbaum,Taccardi,Spiecker,Wasserscheid
, p. 1411 - 1415 (2011)
Exploitation of hydrogen as an energy carrier requires the development of systems for its storage and delivery. Formic acid has been proposed as valuable hydrogen carrier compound, due to its relatively high hydrogen content (53 g L-1), the latter being easily and cleanly released in catalytic reactions under mild conditions (HCOOH → H2 + CO2). Ionic liquids are interesting solvents for homogeneous catalyzed formic acid decomposition systems as their extremely low volatility avoids solvent contamination of the produced hydrogen stream. In this paper an outstandingly simple, robust and active catalyst system is presented, namely RuCl3 dissolved in 1-ethyl-2,3-dimethylimidazolium acetate (RuCl3/[EMMIM] [OAc]). This system proved to be fully recyclable over 10 times. Turnover frequencies (TOF) of 150 h-1 and 850 h-1 were obtained at 80 °C and 120 °C, respectively.
Theoretical and experimental investigation of the interactions between [emim]Ac and water molecules
Ding, Zhen-Dong,Chi, Zhen,Gu, Wen-Xiu,Gu, Sheng-Ming,Wang, Hai-Jun
, p. 147 - 155 (2012)
Density functional theory (DFT) calculations, atom in molecules (AIM) theory, natural bond orbital (NBO) analysis and infrared (IR) spectroscopy were performed to investigate the interactions between water molecules and ionic liquid 1-ethyl-3-methylimidazolium acetate ([emim]Ac). It was found that [emim]Ac interacts with water molecules mainly via H-bonds, and the anionic part of [emim]Ac plays a major role in the interaction with H2O. The energies of H-bonds were estimated from spectral shifts of hydroxy antisymmetric stretching vibration. Moreover, the experimental results also indicated that hydroxy of water mainly interacts with the COO- of [emim]Ac. Further studies indicated that the intensity of hydroxy stretching vibrations tend to be stronger with the increase of the concentration of water. In addition, the frequency of hydroxy stretching vibrations showed clearly red-shift, and the COO- vibrational frequency gradually shifted to the lower wavenumber region, which were indicative of extended hydrogen bonded network.
Organocatalytic upgrading of the key biorefining building block by a catalytic ionic liquid and N-heterocyclic carbenes
Liu, Dajiang,Zhang, Yuetao,Chen, Eugene Y.-X.
, p. 2738 - 2746,9 (2012)
The present study of rapid degradation of the key biorefining building block 5-hydroxymethylfurfural (HMF) in an ionic liquid (IL), 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), has led to highly selective and efficient upgrading of HMF to 5,5′-di(hydroxymethyl)furoin (DHMF), a promising C12 kerosene/jet fuel intermediate. This HMF upgrading reaction is carried out under industrially favourable conditions (i.e., ambient atmosphere and 60-80 °C), catalyzed by N-heterocyclic carbenes (NHCs), and complete within 1 h; this process selectively produces DHMF with yields up to 98% (by HPLC or NMR) or 87% (unoptimized, isolated yield). Mechanistic studies have yielded four lines of evidence that support the proposed carbene catalytic cycle for this upgrading transformation catalyzed by the acetate IL and NHCs.
Water sorption by ionic liquids: Evidence of a diffusion-controlled sorption process derived from the case study of [BMIm][OAc]
Brandt, Philipp,Janiak, Christoph,Schmitz, Alexa,Spie?, Alex
, (2021/11/24)
The hydrophilicity of ionic liquids (ILs) could be exploited as desiccants or in sorption-driven heat transformation, yet reports of water sorption isotherms of pure ionic liquids are still scarce. Here, water sorption studies for the six pure hydrophilic ionic liquids with 1-ethyl-3-methylimidazolium [EMIm]+ or 1-butyl-3-methylimidazolium [BMIm]+ cations and acetate [OAc]?, formate [HCOO]? or lactate [Lac]? anions show a steady and high water uptake with a small hysteresis between absorption and desorption over the relative pressure range of p/p0 = 0 – 0.9 for the first time. Repeated static volumetric sorption measurements with different amounts or different surface area of the example IL [BMIm][OAc] reveal a slow and strongly diffusion-driven sorption process stemming from the absorption of surface-adsorbed water into the bulk IL. Extrapolation of the water uptake to very small IL amounts with negligible kinetic hindrance gives an equilibrium water uptake capacity of over 2100 mg/g(IL) at p/p0 = 0.9. Gravimetric control experiments at a relative humidity of 75.5 % confirm the time-dependence with the IL surface area at the gas–liquid-interface and the amount of the IL to reach the equilibrium uptake of 1040 mg/g at p/p0 = 0.75.
Carboxylate ionic liquid as well as preparation method and application thereof
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Paragraph 0120; 0123; 0127-0129, (2019/10/23)
The invention provides carboxylate ionic liquid as well as a preparation method and application thereof. According to the carboxylate ionic liquid provided by the invention, an imidazole group or a pyridine group is introduced into the cationic part of the carboxylate ionic liquid and a carboxylic acid group is introduced into the anionic part of the carboxylate ionic liquid; and the ionic liquidcatalyst provided by the invention is simple and convenient in synthesis route, high in yield and easy to recover. Anion carboxylate radical in the carboxylate ionic liquid provided by the invention serves as an active site, so that synthesis of diol can be realized through high-efficiency and high-selectivity catalysis of hydration reaction of epoxy compounds under the condition of not adding other catalysts.
Synthesis of propylene glycol ethers from propylene oxide catalyzed by environmentally friendly ionic liquids
Zhao, Cong,Chen, Shengxin,Zhang, Ruirui,Li, Zihang,Liu, Ruixia,Ren, Baozeng,Zhang, Suojiang
, p. 879 - 888 (2017/05/24)
A series of acetate ionic liquids were synthesized using a typical two-step method. The ionic liquids were used as environmentally benign catalysts in the production of propylene glycol ethers from propylene oxide and alcohols under mild conditions. The basic strengths of the ionic liquids were evaluated by determination of their Hammett functions, obtained using ultraviolet-visible spectroscopy, and the relationship between their catalytic activities and basicities was established. The catalytic efficiencies of the ionic liquids were higher than that of the traditional basic catalyst NaOH. This can be attributed to the involvement of a novel reaction mechanism when these ionic liquids are used. A possible electrophilic-nucleophilic dual activation mechanism was proposed and confirmed using electrospray ionization quadrupole time-of-flight mass spectrometry. In addition, the effects of significant reaction parameters such as concentration of catalyst, molar ratio of alcohol to propylene oxide, reaction temperature, and steric hindrance of the alcohol were investigated in detail.
