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.

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.

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.

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.

Microscopic structures of ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate in water probed by the relative chemical shift

The relative chemical shifts (△δ) △δwere put forward to investigate the microscopic structure of 1-ethyl-3-methyl-imidazolium tetrafluoroborate (EmimBF4) during the dilution process with water.The concentration-dependent △δ(C2)H-(C4)H,△δ(C2)H-(C5)H and △δ(C4)H-(C5)H were analyzed.The results reveal that the variations of the microscopic structures of three aromatic protons are inconsistent.The strength of the H-bond between water and three aromatic protons follows the order:(C2)H···O > (C4)H···O > (C5)H···O.The concentration-dependent △δ(C6)H-(C7)H and △δ(C6)H-(C8)H indicate the formation of the H-bonds of (Calkyl)H···O is impossible,and more water is located around (C6)H than around (C7)H or (C8)H.The concentration-dependent △δ(C2)H-(C4)H and △δ(C2)H-(C5)H both increase rapidly when xwater > 0.9 or so,suggesting the ionic pairs of EmimBF4 are dissociated rapidly.The turning points of concentration-dependent △δ(C2)H-(C4)H and △δ(C2)H-(C5)H indicate that some physical properties of the EmimBF4/water mixtures also change at the corresponding concentration point.The microscopic structures of EmimBF4 in water could be clearly detected by the relative chemical shifts.

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

The Hartree-Fock method has been employed to investigate the electronic structures of EMIM^＋（1-ethyl-3-methyl-imidazolium^＋）, CuCl2^-, Cu2Cl3^-, CuCl3^2-, EMIM＋^-CuCl2^-, EMIM^＋-Cu2Cl3^-, and EMIM^＋-CuCl3^2- pairs. Full optimization and frequency analyses of EMIM^＋, CuCl2^-, Cu2Cl3^-, CuC13^-, eight initial EMIM^＋-CuCl2^-, six EMIM^＋-Cu2Cl3^-, and four EMIM^＋-CuCl3^2- geometries have been carried out using Gaussian-94 soft-package at 6-31＋G（d,p） basis set level for hydrogen, carbon, nitrogen, chlorine atoms and Hay-Wadt effective core potential for copper atom. The electronic structures of lowest energy of EMIM^＋-CuCl2^-, EMIM＋-Cu2Cl3^-, EMIM^＋-CuCl3^2-, single EMIM^＋, CuCl2^-, Cu2Cl3^-, and CuCl3^2- have been comparatively studied. The calculated results showed that EMIM^＋-CuCl2^- pair conformer of lowest energy was five ring parallel to Cl-Cu-Cl with 3.2A distance, EMIM^＋-CuCl3^2- pair conformer of lowest energy was five ring parallel to CuCl3^2-plane with 3.4A distance, and the optimized EMIM^＋-Cu2Cl3^- pair conformer of lowest energy was five ring perpendicular to Cl-Cu-Cl-Cu-Cl plane with 3.0A distance between the terminal Cl atoms and the 5-ring of EMIM^＋. The cohesion between cations and anions is brought about by C-H. C1 hydrogen bonds that are reinforced by charge assistance. The frequency analyses suggested that all stationary points are minimum because of no appearing of imaginary frequency. The assigned frequencies were in agreement with the experimental report. The low energy of interaction because of the bulkyasymmetry of EMIM＋ and the charge dispersion of cation and anion leads to the low melting point of the ionic liquids, EMIM^＋-CuCl2^-, EMIM^＋-Cu2Cl3^-, and EMIM^＋-CuCl3^2-. The interaction energy of EMIM^＋-CuCl2^-, EMIM^＋-Cu2Cl3^-, and EMIM^＋-CuCl3^2- is 309.0 kJ/mol, 316.8 kJ/mol, and 320.2 kJ/mol, respectively. The relationship of interaction energy via distance between cations and anions was also investigated by single point energy scan.

Synthesis and Crystal Structure of Tri(4-(3-hydroxy2-ethyl-4-pyridinone-1-yl)-aniline Condensation Salicylaldehydato) Monohydratotricopper(II)Dimethylformamide Monohydrate Solvate

The title complex [Cu3L3(H2O)]DMFH2O (H2L = 4-(3-hydroxy-2-ethyl-4- pyridinone-1-yl)-aniline condensation salicylaldehyde) was obtained. The single-crystal X-ray study shows that it is a trinuclear compound [Cu3(C20H15N2O3)3(H2O)]DMFH2O. The coordi- nation sphere about each copper ion in the complex consists of two oxygen atoms from hydroxylpyridinone moiety of one ligand and one oxygen and one nitrogen atoms from salicyladehyde Schiff-base moiety of another ligand arranged in a slightly distorted square planar geometry. Among the three copper ions, one (Cu(2)) is coordinated by the other oxygen atom of water molecule on the fifth coordinate position to form a distorted square pyramid geometry. The crystal is of monoclinic, space group P21/c with a = 12.9202(5), b = 27.197(1), c = 17.0116(7) ? b = 100.588(1), V = 5875.9(4) 3, Z = 4, C63H57N7O12Cu3, Mr = 1294.78, Dc = 1.464 g/cm3, m = 1.146 mm-1, F(000) = 2668, R = 0.0784 and wR = 0.1546 for 6926 observed reflections with I > 2s(I). The differences of coordinate bond lengths are observed between anhydrous and hydrous units: in the former unit, the average bond lengths are 1.978 ?for CuN (azomethine), 1.883 ?for CuO (phenolic) in Schiff-base moiety, 1.959 ?for CuO (keto), and 1.919 ?for CuO (hydroxy) in hydroxypyridinone moiety; while those in the latter are longer with the following corresponding values: 1.985(5), 1.908(5), 1.993(5) and 1.919(4) ? respectively. The Cu(2)O (water) bond length is 2.375(6) ?

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

Hartree-Fock 方法被采用了调查 EMEVI^+(1-ethyl-3-methylimidazohum ^+) 的电子结构， AlCl_4^- ，和 EMIM^+-AlCl_4^- 。EMIM^+ 的完整的优化和频率分析， AlCl_4^- ，十起始的 EMIM^+-AlCl4 几何学用在 6-31+G 软包裹的 Gaussian-94 被执行了(d， p ) 为氢，碳，氮，氯，和铝的基础集合水平原子。EMIM^+-AlCl_4^- 对，单个 EMIM^+ ，和 AlCl_4^- 的最低精力的电子结构比较地被学习了。计算结果证明最低精力的优化 EMIM^+-AlCl_4^-pair conformer 与 2.7 A 的 H6-Cl22 距离是在在甲基组和乙醇组之间的五戒指的飞机外面的 AlCl_4^- 。频率分析建议因为出现的没有想象的频率，所有静止的点是最小的点，并且分配频率与试验性的报告一致。在 EMIM^+ 和 AlCl_4^- 之间的相互酌能是 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 of EMIM+(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 6-31+G (d, p) basis set level for hydrogen, carbon, nitrogen, chlorine atoms and the Hay-Wadt effective core poten- tial 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?, 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 ? 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.

Synthesis and Crystal Structure of 3-(1-Ethyl-1H-indole-3-carbonyl)aminopropionic Acid

3-（1-Ethyl-1H-indole-3-carbonyl）aminopropionic acid has been synthesized by alkylation of 3-（1H-indole-3-carbonyl）aminopropionic acid methyl ester with bromoethane,follo-wed by saponifying and acidating,in 89.0% yield.Its crystal structure was gotten and determined by X-ray diffraction method.The crystal is of orthorhombic,space group P212121 with a = 8.9490（12）,b = 11.1010（15）,c = 13.0475（18） ,V = 1296.2（3） 3,Z = 4,Dc = 1.334 g/cm3,λ = 0.71073 ,μ（MoKα） = 0.095 mm-1,Mr = 260.29 and F（000） = 552.The structure was refined to R = 0.0306 and wR = 0.1445 for 2612 observed reflections with I 2σ（I）.In the crystal structure,molecules are linked to each other through hydrogen bonds of N（2）-H（2）···O（1） and O（3）-H（3）···O（1）,generating a three-dimensional network.

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.

乙酸乙酯-乙醇-1-乙基-3-甲基四氟硼酸咪唑盐物系等压汽液平衡数据的测定

在101.32 kPa 下,用改进的 Othmer 釜测定了含离子液体1-乙基-3-甲基咪唑四氟硼酸盐([EMIM]BF_4)的乙酸乙酯-乙醇物系的等压汽液平衡数据。实验结果表明,加入[EMIM]BF_4使汽液平衡线偏离乙酸乙酯-乙醇二组分物系的汽液平衡线,[EMIM]BF_4含量越高,偏离程度越大;[EMIM]BF_4表现出盐效应,使乙酸乙酯对乙醇的相对挥发度发生改变,消除了乙酸乙酯-乙醇物系的共沸点;[EMIM]BF_4含量越高,盐效应越明显,随[EMIM]BF_4含量的增加,乙酸乙酯对乙醇的相对挥发度增加。[EMIM]BF_4可以作为乙酸乙酯-乙醇物系萃取精馏的溶剂,适宜的[EMIM]BF_4摩尔分数约为20%。

1-乙基-3-甲基咪唑四氟硼酸盐离子液体的量子化学研究

采用量子化学的从头算(abinitio)和密度泛函(DFT)方法,在6311++G计算水平上研究了离子液体1乙基3甲基咪唑四氟硼酸盐在气相模型下的离子对结构.经振动分析得到了离子对的红外谱,并利用自然键轨道(NBO)分析了阴阳离子与离子对的电荷布居差异.计算结果表明,离子对中存在氢键等弱相互作用.运用Counterpoise方法消除基组重叠误差,得到阴阳离子间的相互作用能为346.78kJ/mol.

溴化1-乙基-3-甲基咪唑的合成与表征

实验以溴乙烷和N-甲基咪唑为原料合成了离子液体中间体溴化1-乙基-3-甲基咪唑,优化了合成条件,即在室温下,回流2 h。利用红外光谱法对其进行了化学结构的表征;通过紫外光谱法考察了不同溶剂对离子液体中间体的影响,溶剂的极性和酸碱性对离子液体中间体的紫外光谱均有影响。考察了离子液体中间体在常用溶剂中的溶解性,得出EMIMBr在水、乙醇、甲醇、乙酸、乙腈、丙酮等溶剂中有较好的溶解性;在乙醚、乙酸乙酯、三氯甲烷、四氯化碳、环己烷溶剂中不溶或难溶的结论。

1-乙基-3-甲基咪唑二氨腈盐中各类溶质无限稀释活度系数的测定

采用反相气相色谱法将离子液体作为固定相测定了27种溶质(烷烃、芳烃,卤代甲烷、醇、酮、醚、酯、三乙胺、二硫化碳、四氢呋喃、乙腈、吗啡啉、吡啶和水)在离子液体1-乙基-3-甲基咪唑二氨腈盐([EMIM][N(CN)2])323.15K,333.15K,343.15K和353.15K下的无限稀释活度系数γ1,3∞。通过计算不同溶质无限稀释活度系数的比值,探讨了[EMIM][N(CN)2]作为共沸、萃取精馏和萃取操作中的夹带剂或萃取剂的可行性。结果显示[EMIM][N(CN)2]在含水以及极性不对称性较大的共沸二元体系中有很好的选择性。此外,通过温度与γ1,3∞值的关系得到溶质的无限稀释偏摩尔焓。

乙酸甲酯-甲醇-1-乙基-3-甲基咪唑四氟硼酸盐物系等压汽液平衡数据的测定与关联

在101.3kPa下,用改进的Othmer釜测定了乙酸甲酯-甲醇-1-乙基-3-甲基咪唑四氟硼酸盐([emim]BF4)三组分物系的等压汽液平衡数据。实验结果表明,加入[emim]BF4,乙酸甲酯-甲醇二组分物系的汽液平衡线发生偏离,离子液体摩尔分数越大,偏离程度越大;[emim]BF4表现出盐效应,使乙酸甲酯对甲醇的相对挥发度增加。用NRTL模型对汽液平衡的实验数据进行了关联,得到二组分交互作用参数。采用该模型参数,乙酸甲酯-甲醇-[emim]BF4三组分物系乙酸甲酯的汽相摩尔分数的实验值与计算值的绝对平均偏差为0.003,温度平均偏差为0.3K。

1-乙基-3-甲基咪唑醋酸盐溶剂小间隙干湿纺纤维素纤维的结构与性能

通过1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)溶剂小间隙下的干湿法纺丝,制备了不同间隙和牵伸速率条件下的纤维素纤维;采用密度梯度法、压汞法、广角X射线衍射(WAXD)、双折射、纤度强伸联用仪和湿摩擦等方法,对纤维素纤维的结构与力学性能进行表征。结果表明:采用密度法测量的纤维素纤维的密度和结晶度准确性高,采用WAXD法测量的结晶度适用于相对比较;所得纤维结构致密;在小间隙纺丝条件下,增加间隙有利于原液细流内应力的松弛,适当提高牵伸速率,有利于纤维结晶度、取向度的提高,所得纤维的物理机械性能较好。

超声强化溴化1-乙基-3-甲基咪唑从黄花蒿中提取青蒿素

利用超声强化[emim]Br(溴化1-乙基-3-甲基咪唑)-水体系从黄花蒿粉末中提取青蒿素.正交实验和单因素实验结果表明,影响黄花蒿中青蒿素提取因素的显著性次序为液固比>提取时间>提取温度>超声波功率>占空比.综合考虑单因素实验结果及成本,得出优化工艺条件为黄花蒿原料粒度0.38mm,液固比50mL/g,提取时间30min,提取温度20℃,超声波功率600W,占空比1.6s/0.4s.在上述条件下青蒿素提取量为4.37mg/g,提取率为97%.

壳聚糖在1-乙基-3-甲基咪唑醋酸盐溶液中的流变行为

离子液体1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)对壳聚糖具有良好的溶解能力。利用新一代旋转流变仪哈克MARS-Ⅲ考察了壳聚糖-[EMIM]Ac溶液的稳态流变和动态流变性能。稳态流变结果表明:当低黏均分子量壳聚糖离子液体溶液的质量分数在3%以下时,溶液呈牛顿性流体特征,高于此质量分数时溶液呈假塑性流体特征;壳聚糖离子液体溶液的黏度、结构黏度指数随着温度升高而降低;在同一质量分数下,溶液黏度随壳聚糖黏均分子量的增大而增加,溶液的恒剪切活化能黏流活化能随着剪切速率的增大而降低。动态流变结果表明:溶液的储能模量和损耗模量随着温度的升高而下降,储能模量与损耗模量存在一个交叉点,该交叉点随着温度升高向高频区移动。

乙酸乙酯-乙醇-1-辛基-3-甲基咪唑四氟硼酸盐物系汽液平衡数据的测定

在101.32 kPa下,用改进的Othmer汽液平衡釜测定了乙酸乙酯-乙醇-1-辛基-3-甲基咪唑四氟硼酸盐([omim]BF_4)三组分物系的等压汽液相平衡数据。采用NRTL方程对实验数据进行了关联,得到方程参数,活度系数的计算值与实验值的偏差为3.12%。实验结果表明,加入[omim]BF_4使汽液平衡线偏离乙酸乙酯-乙醇二组分物系的汽液平衡线,[omim]BF_4含量越大,偏离程度越大;[omim]BF_4具有明显的盐析效应,能够增大乙酸乙酯对乙醇的相对挥发度;当x([omim]BF_4)为10%时,乙酸乙酯-乙醇物系的共沸点消失,随[omim]BF_4含量的增加,乙酸乙酯对乙醇的相对挥发度增加。