Scale-up of biomass conversion using 1-ethyl-3-methylimidazolium acetate as the solvent

This scale-up study demonstrated the feasibility of an ionic liquid(IL)pretreatment process at 40 kg scale,using the IL 1-ethyl-3-methylimidazolium acetate([C2C1Im][OAc])as the solvent.The pretreatment was followed by enzymatic hydrolysis through which the process efficiency for biomass conversion to monomeric sugars was determined.The results show that 43 wt%of switchgrass was dissolved in IL after 2 h of pretreatment at 160℃ with 15 wt%solid loading.A 120 h enzymatic hydrolysis of the pretreated switchgrass results in 96%glucan and 98%xylan conversion.[C2C1Im][OAc]pretreatment has been successfully scaled up to 40 kg with improved sugar titers and yields relative to bench scale(6 kg).The mass flow of the overall process was established and the major scale-up challenges of the process were identified.

Synthesis and physico-chemical properties of new green electrolyte 1-butyl-3-methylimidazolium perchlorate

1-butyl-3-methylimidazolium perchlorate([BMIM]ClO4) was synthesized by two steps with N-methylimidazolium.Some physico-chemical properties,such as density,surface tension,viscosity,electrical conductivity as well as electrochemical window,were investigated and solvent performance was also studied.The results show that this kind of ionic liquid is an excellent electrolyte with low viscosity,high electrical conductivity and wide electrochemical window.In addition,[BMIM]ClO4 is soluble in most conventional solvents and some metal oxides have high solubility in it,which lays the foundation of direct electrolysis of metal oxides in this ionic liquid.

DFT Study on the Structure of Ionic Liquid 1-Ethyl-3-methylimidazolium Hexafluorophosphate

This paper reports the ab initio and Density Functional Theory (DFT) studies on the structure of the ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMIM]+[PF6]-). Hartree-Fock (HF) and DFT(B3LYP) methods are respectively used to obtain the stable structure of the gas phase ion pair at the 6-311++G(d, p) basis set level. The theoretical IR spectra of [EMIM]+[PF6]- were obtained from the calculated vibrational frequencies and intensities. The changes of atomic charge population have been investigated using Natural Bond Orbital (NBO) analysis. The computational results show that there may exist hydrogen bonds between the cation and the anion. After ZPE and BSSE corrections, the interaction energy between the cation and the anion is –314.44 kJ?mol-1.

Interactions of 1-hexyl-3-methylimidazolium Bromide with Acetone

^1H and ^13C NMR chemical shifts were determined to investigate the interactions of acetone with a room temperature ionic liquid 1-hexyl-3- methylimidazolium bromide [C6mim]Br at various mole fractions. Changes in chemical shifts of hydrogen nuclei and of carbon nuclei with the acetone concentration indicated the formation of hydrogen bond between anion of the ionic liquid and methyl protons of acetone. The NMR results were in good agreement with the ab initio computational results.

Crystal Structure,Thermal Behavior and Luminescence of a New Dimeric Manganese(Ⅱ) Complex Constructed with 3-Carboxy-1-carboxymethyl-2-oxidopyridinium

A new dimeric Mn（Ⅱ） complex,namely,[Mn（L）（PIP）]_2·H_2O（1）,was synthesized under hydrothermal condition（H_2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium and PIP = 2-（pyridin-3-yl）-1H-imidazo[4,5-f][1,10]phenanthroline）.It crystallizes in triclinic,space group P1 with a = 9.2037（13）,b = 9.6794（13）,c = 14.649（3） A,α = 94.858（3）,β = 94.928（3）,γ = 114.468（2）o,V = 1172.9（3） A^3,Z = 1,C_（52）H_（34）Mn_2N_（12）O_（11）,Mr = 1112.79,Dc = 1.575 g/cm^3,F（000） = 568,μ（Mo Ka） = 0.618 mm^-1,R = 0.0432 and w R = 0.1151.In 1,two L anions bridge two Mn（Ⅱ） atoms to give a dimeric [Mn（L）（PIP）] unit with the Mn···Mn distance of 3.009（2） A.The two PIP ligands are located on both sides of the dimer,which provides suitable π-π stacking interactions between PIP ligands.By these π-π stacking interactions,adjacent dimers are extended into a two-dimensional supramolecular layer.Further,the strong N–H···O hydrogen bond stabilizes the supramolecular layer structure of 1.Moreover,the thermal behavior and luminescent property of 1 have been studied.

Novel efficient procedure for biodiesel synthesis from waste oils with high acid value using 1-sulfobutyl-3-methylimidazolium hydrosulfate ionic liquid as the catalyst

Preparation of biodiesel from waste oils containing 72% of free fatty acids catalyzed by a novel Br?nsted acidic ionic liquid 1-sulfobutyl-3-methylimidazolium hydrosulfate([BHSO_3MIM][HSO_4]) was systematically investigated.The optimum molar ratio of methanol to waste oils,catalyst amount,reaction temperature and reaction time were 8/1,10%(based on the mass of waste oils),140°C and 6 h,respectively,under which the obtained yield of biodiesel reached 94.9%.Also,[BHSO_3MIM][HSO_4] as a catalyst still retained around 97% of its original catalytic activity after successive re-use of 5 batches(6 h per batch),showing the excellent operational stability.Moreover,the acidic IL [BHSO_3MIM][HSO_4] was able to ef ficiently catalyze conversions of waste oils with different amounts of FFAs(free fatty acids) into biodiesel,and showed tremendous application potential.Therefore,an ef ficient and environmentally friendly catalyst is provided for the synthesis of biodiesel from waste oils with high acid value.

Removal of Trace Olefins from Aromatics by Catalytic Alkylation Using 1-Alkyl-3-methylimidazolium Bromochloroaluminate Catalyst

Removal of trace olefins from aromatic liquids had been investigated in the presence of various ionic liquids like 1-ethyl-3-methylimidazoliurn bromochloroaluminate （EMIMBr-AlCl3）, 1-butyl-3-methylimidazolium bromochloroaluminate （BMIMBr-AlCl3）, l-hexyl-3-methylimidazolium bromochloroaluminate （HMIMBr-AlCl3）, and 1-octyl-3-methylimidazolium bromochloroaluminate （OMIMBr-A1C13）. It was found that the longer the alkyl chain of ionic liquid cations was, the higher the olefins conversion would be. OMIMBr-AlCl3 （with 0.67 molar fraction of AlCl3） had an obvious performance on olefins removal. The influences of various reaction parameters such as the dosage of catalyst, the reaction temperature, and the reaction time on the reaction catalyzed by OMIMBr-AlCl3 were investigated. Under optimum reaction conditions, a higher than 99% conversion of olefins was achieved. The preliminary results revealed that the process could save time, consume less energy, separate products easier, and cause less pollution to the environment.

Oil recovery tests with ionic liquids: A review and evaluation of 1-decyl-3-methylimidazolium triflate

The main advantages of the use of ionic liquids in enhanced oil recovery are their tunability and stability in harsh environmental conditions. In this work, a comprehensive review of ionic liquids proposed to improve current chemical oil recovery methods has been presented, focusing on core flooding experiments. With an almost infinite number of possible ionic liquids, the amount of experiments carried out up to now has been very limited. However, results are promising, with additional recovery after secondary flooding of up to 32% of the original oil in place. Most formulations with ionic liquids have been proposed for sandstone reservoirs, the number of studies with carbonate cores being very scarce. The possibilities of a new room temperature surface active ionic liquid, 1-decyl-3-methylimidazolium triflate,for this application were analyzed. It was shown that it is able to drastically reduce the water/oil interfacial tension. An optimized formulation was proposed for carbonate reservoirs. After secondary flooding with brine, an additional recovery of 10.5% of original oil in place was achieved at room conditions. A combination of the proposed method followed by a polymer flooding step with polyacrylamide led to a lesser but still significant recovery, reducing the costs associated to the ionic liquid.

Isobaric Vapor–Liquid Equilibrium for tert-Butyl Alcohol + Water + Propane-1,3-Diol + 1-Ethyl-3-Methylimidazolium Chloride at 101.3 kPa

In this study, we used a mixture of organic liquid propane-1,3-diol and ionic liquid 1-ethyl-3-methylimidazolium chloride([emim]Cl) as the entrainer to separate tert-butyl alcohol(TBA) + water. We measured the isobaric vapor–liquid equilibrium(VLE) for the quaternary system TBA + water + propane-1,3-diol + [emim]Cl at 101.3 kPa, and found the VLE data to be well correlated with the nonrandom two-liquid model. These results show that the mixed solvent of propane-1,3-diol + [emim]Cl can increase the relative volatility of TBA to water and break the azeotropic point. We found no notable synergetic effect between them, and observed that the liquid mixed solvent of propane-1,3-diol and [emim]Cl had lower viscosity than [emim]Cl, which makes it a promising entrainer for separating the TBA + water azeotrope in industrial applications.

Synthesis and Characterization of Poly [2,2-( m-phenylene) -5,5-bibenzimidazole] in 1-butyl-3-methylimidazolium Chloride

Poly[ 2, 2-（m.phenylene） -5, 5-bibenzimidazole] （mPBI） were synthesized by mixing 3, 3＇, 4, 4＇-tetraaminobiphenyl and isophthallc acid in 1 -butyl-3 -methyUmidazolinm chloride （ E BMIM] CI）. Intrinsic viscosity of mPBI polymers was 0.67 dL/g which was measured in 96% sulfuric acid. The polymer was characterized by Fourier transform infrared spectroscopy （FTIR）, nuclear magnetic resonance （ 1H-NMR ）, and thermogravimetric analysis （TGA）. The effects of polymerization conditions on the intrinsic viscosity of mPBI were investigated. It showed that the molecular weight of polymer mainly depended on pre-reaction time and reaction temperature. Comparison of structure and properties of mPBI synthesized in ionic liquids（ILs） and polyphosphoric acid was also reported. It indicates that the ionic liquids are a kind of good solvents in synthesis process of m_PBI and ionic liquids mainly affect molecular weight of mPBL

Impact of Ionic Liquid 1-Ethyl-3-Methylimidazolium Acetate Mediated Extraction on Lignin Features

This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.

氯桥连1-甲基-3-羧甲基咪唑镉一维配位聚合物:[Cd_2(C_6H_8N_2O_2)_2Cl_4]_n·3nH_2O的合成及晶体结构(英文)

A metal-organic coordination polymer [Cd2(C6H8N2O2)2Cl4]n·3nH2O [where C6H8N2O2 is ionic liquid,1-carboxymethyl-3-methylimidazolium] 1 has been hydrothermally synthesized and characterized by X-ray diffraction single-crystal structure analysis.The complex crystallizes in orthorhombic,space group Aba2 with a=1.747 6(3) nm,b=1.933 6(4) nm,c=0.692 75(13) nm,V=2.340 9(8) nm3,Mr=700.96,Dc=1.989 g·cm-3,μ(Mo Kα) =2.312 mm-1,F(000) =1 368,Z=4,the final R=0.021 4 and wR=0.051 2 for 3 331 observed reflections(I>2σ(I) ) .Each Cd(Ⅱ) atom is in a distorted octahedral environment,surrounded by an uncommon symmetrical bidentate chelating carboxylato group and two pairs of bridging chloro ligands.Successive octahedra related by the c-glide of eration share edges to generate a one-dimensional polymeric structure.CCDC:692298.

氯化1-羧甲基-3-甲基咪唑的热稳定性、平衡蒸汽压和升华焓

利用非等温、等温热重分析法（TG）,研究了高纯氮气气氛下氯化1-羧甲基-3-甲基咪唑（[cmmim]Cl）的热稳定性、平衡蒸汽压和标准升华焓.非等温TG曲线表明[cmmim]Cl的初始分解温度和最大分解速率对应的温度分别为547和570 K.然而长期等温TG研究表明,[cmmim]Cl的最高可使用温度约为433 K.另外,利用基于TG的蒸发技术研究了[cmmim]Cl的平衡蒸汽压与温度的关系并计算了标准升华焓.在403~463 K温度范围内,平衡蒸汽压和温度的关系是：lgPe=（9.8±0.2）＋（-2.88±0.09）×103/T.

Ab Initio Calculation of Room Temperature Ionic Liquid 1-Ethyl-3-Methyl-Imidazolium and AlCl_3

The Hartree-Fock method has been employed to investigate the electronic structures of EMIM＋（1- ethyl-3-methylimidazolium＋）, AlCl4^-, and EMIM＋-AlCl4^-. Full optimization and frequency analyses of EMIM＋, AlCl4^-, ten initial EMIM＋-AlCl4^- geometries have been carried out using the Gaussian-94 soft-package at 6- 31＋G（d,p） basis set level for hydrogen, carbon, nitrogen, chlorine, and aluminum atoms. The electronic structures of the lowest energy of EMIM＋-AlCl4^-pairs, single EMIM^＋, and AlCl4^- have been comparatively studied. The calculated results showed that the optimized EMIM^＋-AlCl4^-pair conformer of lowest energy was AlCl4^-outside the five-ring plane between methyl group and ethyl group with a H6--C122 distance of 2.7 A. The frequency analyses suggested that all stationary points were minimum points because of no imaginary frequency appearing, and the assigned frequencies were in agreement with experimental report. The interaction energy between EMIM^＋ and AlCl4^-was 776.2 kJ/mol.

DFT Calculation of Room Temperature Ionic Liquid 1-Ethyl-3-Methyl-Imidazolium Chlorocuprate (Ⅰ)

The density functional theory （DFT） has been employed to investigate the electronic structures ofEMIM^＋（1-ethyl-3-methylimidazolium＋）, CuCl2^-, Cu2Cl3^- and EMIM^＋-CuCl2^-, EMIM^＋-Cu2Cl3^- pairs. Full optimization and frequency analyses of EMIM^＋, CuCl2^-, Cu2Cl3^-, eight initial EMIM^＋-CuCl2^-, and six initial EMIM^＋-Cu2Cl3^- geometries have been carried out using Gaussian-94 software-package at 6-3 I＋G （d, p） basis set level for hydrogen, carbon, nitrogen, chlorine atoms and the Hay-Wadt effective core potential for copper atoms. The electronic structures of the lowest energy of EMIM^＋-CuCl2^-, EMIM^＋-Cu2Cl3^- pairs, single EMIM^＋, CuCl2^-, and Cu2Cl3^- have been comparatively studied. The calculated results showed that the optimized EMIM^＋-CuCl2^- pair conformer of the lowest energy was five ring moiety parallel to CuCl2^- plane with a distance of around 3.5,A, while EMIM^＋-Cu2Cl3^- pair conformer of the lowest energy was five ring moiety of EMIM^＋ perpendicular to Cu2Cl3^- plane with a distance of around 3.0 ,A between terminal chlorine atoms and 5-ring plane of EMIM^＋. The cohesion between cation and anion is electrostatic interaction and C-H---Cl hydrogen bonds are reinforced by charge assistance. The frequency analyses suggested that all stationary points are minimum points because of absence of imaginary frequency. The low energy of interaction caused by bulky asymmetry of EMIM^＋, and charge dispersion of cation and anion give rise to low melting point of ionic liquids EMIM^＋-CuCl2^-, and EMIM^＋-Cu2Cl3^- . The interaction energy caused by the distance between cations and anions was investigated by single point energy scan.

Preparation and Properties of Regenerated Cellulose/Amylopectin Blend Fibers from 1-Butyl-3-Methylimidazolium Chloride with Controlled Biodegradation

Regenerated cellulose/amylopectin blend fibers with controlled biodegradation were produced using dry-jet wet-spinning technology from cellulose/amylopectin/1-butyl-3-methylimidazolium chloride blends.Morphological,structural and chemical analyses revealed that dense,homogeneous and void-free blend fibers were prepared in a two-stage dissolution process.The blend fibers were regenerated from water and treated with water or 95%(volume fraction)ethanol.However,cellulose-amylopectin interactions caused crystalline rearrangements in the blend fibers,resulting in a general decrease in crystallinity.Generally,tensile properties decreased with increasing amylopectin content,except that the blend fibers with 10%(mass fraction)amylopectin exhibited higher tensile strength than the regenerated cellulose control fibers.Ethanol treatment reduced the hydrophilicity of the blend fibers,increasing the crystallinity of the blend fibers.The blend fibers exhibited remarkable degradation,directly proportional to the amylopectin content.Despite higher crystallinity,ethanol-treated blend fibers degraded faster than water-treated fibers,indicating amylopectin and ethanol regulated the degradation.

Preparation of WO3/C Composite and Its Application in Oxidative Desulfurization of Fuel

The WO_3/C composite was successfully prepared by calcination of a mixture of WO_3 and g-C_3N_4 at 520 ℃. The as-synthesized samples were analyzed by X-ray diffraction(XRD), electronic differential system(EDS), scanning electron microscopy(SEM), infrared spectrometry(IR) and the Brunner-Emmet-Teller(BET) techniques. The WO_3/C composite, in comparison with the WO_3 and C_3N_4, features smaller particle size, bigger surface area and higher desulphurization performance. The influence of the reaction temperature, the catalyst dosage, the reaction time, the oxidant dosage, the sulfide type and the extractant dose on desulfurization reaction was studied. The results showed that the WO_3/C composite revealed a higher desulfurization activity than the WO_3. The desulfurization rate could reach up to 95.8% under optimal conditions covering a catalyst dosage of 0.02 g, a H_2O_2 amount of 0.2 mL, a 1-ethyl-3-methylimidazolium ethyl sulfate(EMIES) amount of 1.0 mL, a reaction temperature of 70 ℃ and a reaction time of 180 min. After five recycles, the desulfurization activity of catalyst did not significantly decline.

Selective Synthesis of 2,6-Dimethylnaphthalene by Transalkylation in the Presence of Acid Ionic Liquids [C_nmim]Cl-AlCl_3

A highly selective synthesis of 2,6-dimethylnaphthanlene（2,6-DMN） by transalkylation between 2-methylnaphthanlene（2-MN） and 1,2,4,5-tetramethylbenzene（TeMB） was performed with 1-alkyl-3-methylimidazo- lium aluminum chloride（[Cnmim]Cl-AlCl3） ionic liquids（ILs） as catalysts. The influences of the alkyl group as the organic cation, the acidic strength of [C4mim]Cl-AlCl3 ILs as well as the reaction conditions on the catalytic performance were investigated. [C4mim]Cl-AlCl3 ILs[x（AlCl3）=71%] exhibited high activity and selectivity toward 2,6-DMN. The selectivity to 2,6-DMN and the 2,6-DMN/2,7-DMN ratio reached up to 68.2% and 3.7：1, respectively. The UV-Vis spectrum of TeMB treated by different ILs shows that the protonated degree of TeMB dependeds on the acidity strength of ILs, which has a significant impact on the reaction results. The high protonated degree of TeMB is advantageous to enhancing the conversion of transalkylation and the large stereo-hindrance effect of TeMB is favorable to improving the selecivity to 2,6-DMN.

The Effect of Ionic Liquids on the CaCO_3 Crystal Growth

In this paper, the effect of ionic liquids on the CaCO3 crystal growth has been studied for the first time. The obtained CaCO3 crystals were charactered by the X-ray diffraction and scanning electron micrographs. The results showed that the control ability of ionic liquids for CaCO3 crystals growth was dependent on the counter anion very much.

Phase Behavior of Liquid Crystals Formed in [C12mim]CI/H2O and [C12mim] Cl/Alcohols Systems

Phase behaviors of different binary systems involving 1-dodecyl-3-methylimidazolium chlo- ride （[C12mim]Cl） and H20, [C12mim]Cl and different alcohols （1-butanol, 1-pentanol, 1- hexanol and 1-octanol） are investigated at 25 ℃. Hexagonal liquid crystal phase （H1） is identified in [C12mim]Cl/H2O system, and lamellar liquid-crystalline （Lα） phase is found in [C12mim]Cl/alcohols systems by using polarized optical microscopy and small-angle X-ray scattering techniques. The formation of such phases is considered as a synergetic result of the solvatophobic force and the hydrogen-bonded network comprising an imidazoliuin ring, chloride ion and water （or alcohols）, which can be confirmed by Fourier transform infrared spectra. It is noticeable that in [C12mim]Cl/1-octanol system, the lattice spacings of lamellar phase increase with increasing C12mimCl concentration, which is opposite to the results of [C12mim]Cl/H2O system. This may result mainly from stronger static repulsion among hydrophilic headgroups of imidazolium salts arranged in the bilayers of lamellar structures. Further measurements by differential scanning calorimetry indicate that the lamellar phase is stable within a wide temperature range above room temperature. However, the lattice spacings decrease with the increase of temperature, which may. be due to the softening of the hydrocarbon chain of [C12mim]Cl molecules. In different alcohols systems, it is found that the lamellar lyotropic liquid crystal structure is easier to be formed when the carbon chain length becomes longer.