Aryl C-glycosylation using an ionic liquid containing a protic acid

Aryl C-glycosylation of several glycosyl donors, including unprotected sugars, with phenol and naphthol derivatives in an ionic liquid containing a protic acid proceeded effectively and stereoselectively to give the corresponding aryl C-glycosides in good to high yields. Because the ionic liquid was nonvolatile, the reaction could be carried out under reduced pressure; in addition, the ionic liquid could be reused without loss of effectiveness. These features contribute to the significant advantages of this novel aryl C-glycosylation reaction.     

Synthesis,thermal and lyotropic liquid crystalline properties of protic ionic salts

A series of protic ionic salts were synthesised by a simple acid–base reaction from various pyridine derivatives and dodecylbenzenesulfonic acid in a common organic solvent and characterised in terms of their thermal and lyotropic liquid crystalline properties using various experimental techniques. All of them exhibited lyotropic liquid crystalline phases in toluene, methanol, acetonitrile, dimethyl sulfoxide and water. Their critical concentrations for the formation of biphasic solutions and concentrations for the formation of lyotropic solutions were quite broad depending on the dielectric constants of the solvents. Their lyotropic phases were identified as lamellar phases, since their textures exhibited bâtonnets, oily streaks and mosaic textures. They can potentially be used for many organic transformations, which may have implications in green chemistry.     

A novel glycosylation of inactive glycosyl donors using an ionic liquid containing a protic acid under reduced pressure conditions

The glycosylation of inactive glycosyl donors, such as methyl glycosides and 1-hydroxy sugars with nearly stoichiometric amounts of various alcohols (1.1 equiv) in an ionic liquid containing a protic acid (acid-IL) under reduced pressure conditions proceeded effectively to give the corresponding glycosides in good to high yields. Furthermore, the acid-IL could be reused for additional glycosylations without the loss of efficiency.     

A greener electrochromic liquid crystal based on ionic liquid electrolytes

An electrochromic liquid crystal (ECLC) material composed of only liquid crystal (LC) and ionic liquid (IL) was developed. The LC containing the substituted diphenylacetylene serves as electrochromic (EC) material to realise transmittance and colour change under the direct current (DC) field, while the IL with the designable cation and anion served as electrolyte. Herein, a series of IL electrolytes was screened to investigate how IL tunes the electro-optic performance of the ECLC cell. By testing the electrochemistry window of ILs in EC cells, IL with the [NTf₂]^? anion shows adequate electrochemical stability when the EC material undergoes oxidation and reduction. The electro-optic performance of ECLC containing 1-ethoxy-4-[2-(4-pentylphenyl) ethynyl]-benzene (PEB) and IL was then evaluated by UV-vis spectrometry under the control of an electrochemical work station. Compared with other PEB-IL, PEB-[Bmim][NTf₂] with [Bmim][NTf₂] electrolyte shows a satisfactory transmittance at low operating voltage. Furthermore, Pd NPs in situ formed in [Bmim][NTf₂] reduced the EC potential and improved the light scattering of the ECLC cell. In this work, we also designed a bifunctional device based on polymer dispersed liquid crystal (PDLC) that hosts electrochromic guest molecules, and analysed the electro-optical and electrochromic properties of LC electrolyte mixtures, in order to gain control of the incident daylight and glare in building and automotive applications.     

新型质子离子液体/硅凝胶电解质的制备及其性能

采用一步溶胶-凝胶法首次将质子型离子液体固定于纳米多孔硅骨架中,合成了表面光滑、柔软、透明的质子增强型固态复合凝胶电解质.研究表明,该凝胶电解质结合了无机硅骨架和质子离子液体的双重优点,具有高的热稳定性（〉300℃）、宽的电化学稳定窗口（〉2.8V）和优异的中低温导电性（11.25×10？3Scm？1,80℃）.可望作为一种新型固态电解质应用于先进储能器件.     

A novel promoter, heteropoly acid, mediated chemo- and stereoselective sulfoxide glycosidation reactions

The chemo- and stereoselective glycosidations of sulfinylglycosides and alcohols using a heteropoly acid, H₃PW₁₂O₄₀, as a new promoter have been developed.     

Synthesis of 1,2-azidoalcohols from epoxides using a task-specific protic ionic liquid: 1-hydrogen-3-methylimidazolium azide

A task-specific ionic liquid as an environmentally eco-friendly green catalyst has been synthesized and used in the ring opening of epoxides under green conditions. In order to use protic ionic liquids (PIL), we decided to synthesize 1,2-azidoalcohols via a ring opening reaction of epoxides with 1-hydrogen-3-methylimidazolium azide ([Hmim]N₃), which actually acts as a solvent, a reagent and an activator of the epoxide ring. The reaction was carried out in short times (50–70 min) at 70 °C to give 1,2-azidoalcohol in 80–94% isolated yields.     

Liquid-liquid equilibria of butyric acid for solvents containing a phosphonium ionic liquid

L/L equilibrium data of butyric acid (BA) in aqueous solutions contacted with the solvents containing ionic liquid (IL), trihexyl-(tetradecyl)phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL-104), and a related model are presented. IL-104 and its solutions in dodecane were found to be effective solvents of BA. The values of the distribution coefficients of BA were higher than those for solvents with the widely used extractant trioctylamine, especially at low acid concentrations and were also several-fold higher than those of lactic acid (LA). IL extracted BA only in its undissociated form (BAH) at pH well below pK _a of the acid. The loading of IL was independent of IL concentration and it achieved a value higher than four at saturation. Complexes with 1–5 molecules of BA per one IL molecule were supposed in the mass action model in which the reactive formation of complexes (BAH) _p (IL)(H₂O)₂ was supposed. Up to 10 % of the total extracted BA was extracted physically by dodecane as a monomer and dimer, in the solvent. The water content in the organic phase steeply decreased with the BA concentration, which was caused by splitting water-IL reverse micelles due to the formation of the BAH/IL complexes. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

A novel glycosidation of glycosyl fluoride using a designed ionic liquid and its effect on the stereoselectivity

The glycosidations of glucopyranosyl fluoride and alcohols using an ionic liquid containing a protic acid effectively proceeded under mild conditions to afford the corresponding glycosides in good to high yields. The stereoselectivity of the glycosidation was significantly affected by the ionic liquid solvent. 1-n-Hexyl-3-methylimidazolium trifluoromethanesulfonate (C₆mim[OTf]), containing a trifluoromethanesulfonate anion, and 1-(3-cyanopropyl)-3-methylimidazolium trifluoromethanesulfonimidide (CNC₃mim[NTf₂]), possessing a cyano group at the side chain of the imidazolium cation, gave the β-stereoselectivity.     

A cross-linker containing aldehyde functionalized ionic liquid for chitosan

The synthesis of conductive and eco-friendly new chitosan composite biopolymer with a novel aldehyde functionalized ionic liquids (AFILs) was investigated in this work. The AFILs, 1,1′-(pentane-1,5-diyl) bis(4-formylpyridin-1-ium) dibromide (C₅PyBr), 1,1′-(octane-1,8-diyl) bis(4-formylpyridin-1-ium) dibromide (C₈PyBr) and 1,1′-(decane-1,10-diyl) bis(4-formylpyridin-1-ium) dibromide (C₁₀PyBr) have been synthesized and they were characterized by FT-IR, UV–vis and ¹H-NMR and ¹³ C-NMR, TG, and DSC analyses. The synthesized AFILs, C₅PyBr C₈PyBr and C₁₀PyBr were used as cross-linker for chitosan biopolymers and the cross-linked chitosan composites, chitosan/1,1′-(pentane-1,5-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C₅PyBr), chitosan/1,1′-(octane-1,8-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C₈PyBr) and chitosan/1,1′-(decane-1,10-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C₁₀PyBr) were prepared. Herein, the synthesized AFILs have not only cross-linked chitosan, but also provide them the desired novel, functional groups. The prepared chitosan composites were characterized by FT-IR for the analysis of structural, TG and DSC for the thermal behavior, and an electrometer for the electrical conductivity. The electrical conductivity of the prepared Ch/C₅PyBr composite was measured as 1.69?×?10^?5 ± 2.37?×?10^?5 S cm^?1 by the four-point probe at room temperature and this value is higher about 4500-fold than the electrical conductivity of the chitosan.     

Direct and stereoselective synthesis of β-d-mannosides using 4,6-O-benzylidene-protected mannosyl diethyl phosphite as a donor

A direct and practical method for the construction of β-mannosidic linkages is described. While β-selectivities in the TMSOTf-promoted glycosidation of 2,3,4,6-tetra-O-benzyl-d-mannosyl diethyl phosphite are found to be highly dependent on the reactivity of acceptor alcohols, 2,3-di-O-benzyl-4,6-O-benzylidene-d-mannosyl diethyl phosphite reacts with a wide range of acceptor alcohols in the presence of TMSOTf in CH₂Cl₂ at −45 °C to give β-mannosides in high yields with good to high β-selectivities.     

纤维素经离子液体预处理酶解糖化研究

利用离子液体氯化1－丁基－3－甲基－咪唑（[C4mim]Cl）进行纤维素预处理。实验表明,纤维素经离子液体预处理后聚合度下降;糖化速度随预处理温度增加呈现先增大后下降的趋势,在90℃出现最大值;延长预处理时间和采用乙醇作为沉淀剂,可促进酶解糖化。与未处理的纤维素相比,经离子液体预处理后纤维素的糖化速度可提高70％。根据扫描电子显微镜（SEM）观察,纤维素出现了明显的解聚。     

Green and rapid preparation of thermally stable and highly organosoluble polyamides containing L‐phenylalanine‐9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboximido moieties

A chiral diacid monomer containing L ‐phenylalanine‐9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboximido unit was successfully synthesized in four steps and used in the preparation of a series of novel optically active polyamides by direct polycondensation with diverse aromatic diamines using 1,3‐dipropylimidazolium bromide under microwave dielectric heating. Ionic liquids (ILs) efficiently absorb microwave energy and thus are employed as solvent. By controlling the concentration of 1,3‐dipropylimidazolium bromide, reaction time and power level, high yield and moderate inherent viscosity polymers could be achieved in a very short period of time. All the resulting polymers exhibited excellent solubility in various organic solvents. The polyamides were found to have inherent viscosities in the range of 0.54–0.85 dL g^?1. These polyamides had glass‐transition temperatures (T_g) above 180°C, and a 10% weight‐loss temperatures in excess of 340°C with char yield at 800°C in nitrogen higher than 40%. A comparative study on effects exerted by microwave technique with conventional method is also presented. Copyright © 2009 John Wiley & Sons, Ltd.     

功能化离子液体催化合成柠檬酸三丁酯的研究

柠檬酸三丁酯(TBC)是一种新型无毒塑料增塑剂,具有相溶性好、增塑效率高、无毒、不易挥发、抗霉性、耐候性强等特点而备受关注,成为首选替代邻苯二甲酸酯类的绿色环保产品.随着人们环保意识的增强及法规的日益完善,开发生产柠檬酸三丁酯具有极好的发展前景.     

在离子液体中利用Perkin反应合成肉桂酸

肉桂酸(3-苯基-2-丙烯酸)是一种重要的有机化工原料和中间体,广泛应用于医药工业、香料工业和其它精细化工等领域。本研究用离子液体作溶剂,无水碳酸钾为碱催化剂,用Perkin法[1-4]合成了肉桂酸,产率最高可达80·8%。1实验部分1.1离子液体的合成离子液体的合成见文献[5],在500mL     

Polystyrene sulfonic acid catalyzed greener synthesis of hydrazones in aqueous medium using microwaves

An environmentally benign aqueous protocol for the synthesis of cyclic, bi-cyclic, and heterocyclic hydrazones using polystyrene sulfonic acid (PSSA) as a catalyst has been developed; the simple reaction proceeds efficiently in water in the absence of any organic solvent under microwave irradiation and involves basic filtration as the product isolation step.     

计算离子液体溶液汽液相平衡的分子热力学模型

用平均球近似理论、微扰理论和UNIFAC基团贡献方法分别考虑离子之间的长程静电作用、离子与溶剂之间的中程静电作用以及所有粒子之间的短程作用,本文提出了一种新的分子热力学模型,可用于离子液体溶液中溶剂活度系数的计算.通过对含烷基咪唑磷酸酯类离子液体与水、甲醇或乙醇组成的9个二元体系的饱和蒸汽压数据进行关联,获得了相关的模型参数,即溶剂的分子直径和基团之间的交互作用能参数.溶剂活度系数及饱和蒸汽压的计算结果与实验值的平均偏差为1.40%,符合良好,因此本模型可望用于含离子液体体系汽液相平衡的预测.     

吡咯烷酮酸性离子液体中硼酸酯的催化合成

研究了硼酸与频哪醇和环己醇在离子液体1-甲基-2-吡咯烷酮硫酸氢盐（[Hnmp]HSO4）、1-丁基-3-甲基咪唑四氟硼酸盐（[Bmim]BF4）及1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6)中生成2-环己氧基-4,4,5,5-四甲基-1,3,2-二氧硼烷的酯化反应。 考察了不同离子液体、反应温度、反应时间和离子液体与反应物物质的量比等对反应的影响。 结果表明,当n(硼酸)∶n(频哪醇)∶n(环己醇)∶n([Hnmp]HSO4)=1∶1∶1∶1,反应温度为70 ℃和反应时间为4 h时,硼酸酯的产率为72.5%,离子液体重复使用4次,催化活性无明显降低。