酸性功能化离子液体催化“一锅法”合成酰胺烷基萘酚

用磺酸型离子液体1-甲基-3-磺酸丙基咪唑硫酸氢盐([MIMPS][HSO₄])催化β-萘酚、芳香醛和酰胺（或脲）3组分“一锅法” 类Ritter反应合成了酰胺烷基萘酚。 投料比为n(β-萘酚)∶n(芳香醛)∶n(酰胺或脲)∶n([MIMPS][HSO₄])=1∶1∶1.3∶0.1,无需溶剂,恒温125 ℃反应5～40 min,通过简单水洗抽滤即可分离产物,酰胺烷基萘酚产率为85%～97%。 离子液体[MIMPS][HSO₄]可回收重复使用4次,其催化活性无明显降低。 探讨了醛、酰胺或脲结构对反应的影响及可能的反应机理。     

High performance "ionic liquid" chromatography

We firstly developed high performance liquid chromatography methods with "ionic liquids" as eluents (HPILC) and successfully demonstrated the analysis of various biopolymers including scarcely soluble highly polymerized cellulose by means of HPILC with highly polar ionic liquid.     

Ionic Liquids-New "Solutions" for Transition Metal Catalysis

Ionic liquids are salts that are liquid at low temperature (<100 degrees C) which represent a new class of solvents with nonmolecular, ionic character. Even though the first representative has been known since 1914, ionic liquids have only been investigated as solvents for transition metal catalysis in the past ten years. Publications to date show that replacing an organic solvent by an ionic liquid can lead to remarkable improvements in well-known processes. Ionic liquids form biphasic systems with many organic product mixtures. This gives rise to the possibility of a multiphase reaction procedure with easy isolation and recovery of homogeneous catalysts. In addition, ionic liquids have practically no vapor pressure which facilitates product separation by distillation. There are also indications that switching from a normal organic solvent to an ionic liquid can lead to novel and unusual chemical reactivity. This opens up a wide field for future investigations into this new class of solvents in catalytic applications.     

Synthesis and characterization of novel chiral imidazolium and pyridinium ionic liquids derived from tartaric acid and 2-oxazolidinone

Abstract

Novel chiral imidazolium and pyridinium ionic liquids based on tartaric acid and 2-oxazolidinone were designed. Symmetrical dicationic ionic liquids based on tartaric acid have been synthesized and characterized. These chiral ionic liquids were designed by employing very short and simple methods. Incorporation of alkyl halide over tartaric acid and 2-oxazolidinone is an important step. N-methyl imidazole and pyridine were used for preparation of quaternary salts. These ionic liquids have been evaluated for the asymmetric sulfide oxidation. Chiral ionic liquids based on tartaric acid showed superior chiral inducing property as compare to 2-oxazolidinone based chiral ionic liquids.     

Stability Constants of Zinc and Cadmium Complexes of 2-Hydroxypropene-1,3-Diamine-N,N,N",N"-Tetraacetic Acid

Stability constants of complexes of 2-hydroxypropene-1,3-diamine-N,N,N",N"-tetraacetic acid with Zn²⁺ and Cd²⁺ ions have been determined by potentiometric titration in a KNO₃ supporting electrolyte at 298.15 K and ionic strengths of 0.1, 0.5, and 1.0. The results obtained were extrapolated to the zero ionic strength of the solution using a one-parameter equation.     

Study on biodegradable polymer. 3. Synthesis and characterization of poly(DL-lactic acid)-co-poly(ethylene glycol)-co-poly(L-lysine) copolymer

The synthesis of poly(DL-lactic acid)-co-poly(ethylene glycol)-co-poly(L-lysine) copolymer was investigated by the reaction of amino acid-N-carboxy anhydride with lactic acid anhydrosulphite and methoxypolyoxyethylene amine (MPEG-NH₂). The successful synthesis was obtained after adding dibutylmegnesium into the system. The product was proved to be copolymer. The solubility of the polymer revealed that it was ionic polymer.     

Aggregation work at polydisperse micellization: ideal solution and "dressed micelle" models comparing to molecular dynamics simulations

General thermodynamic relations for the work of polydisperse micelle formation in the model of ideal solution of molecular aggregates in nonionic surfactant solution and the model of "dressed micelles" in ionic solution have been considered. In particular, the dependence of the aggregation work on the total concentration of nonionic surfactant has been analyzed. The analogous dependence for the work of formation of ionic aggregates has been examined with regard to existence of two variables of a state of an ionic aggregate, the aggregation numbers of surface active ions and counterions. To verify the thermodynamic models, the molecular dynamics simulations of micellization in nonionic and ionic surfactant solutions at two total surfactant concentrations have been performed. It was shown that for nonionic surfactants, even at relatively high total surfactant concentrations, the shape and behavior of the work of polydisperse micelle formation found within the model of the ideal solution at different total surfactant concentrations agrees fairly well with the numerical experiment. For ionic surfactant solutions, the numerical results indicate a strong screening of ionic aggregates by the bound counterions. This fact as well as independence of the coefficient in the law of mass action for ionic aggregates on total surfactant concentration and predictable behavior of the "waterfall" lines of surfaces of the aggregation work upholds the model of "dressed" ionic aggregates.     

Self-associated, "distillable" ionic media

Liquid or low melting association products of carbon dioxide and a secondary amine, both neutral molecules that may be gaseous, are recognised as "distillable" ionic media.     

Synthesis of Tetrahydrofuran and Tetrahydropyran Derivatives Catalyzed by Tungstophosphoric Acid in Ionic Liquid

Synthesis of tetrahydrofuran and tetrahydropyran derivatives catalyzed by tungstophosphoric acid （H3PW12040） were conveniently performed with high yield from the corresponding unsaturated alcohols in ionic liquid. Sufuric acid （H2SO4）, trifluoromathanesulfonic acid （TfOH） and p-toluenesulfonic acid （TsOH） were also explored for preparing these products in ionic liquid. The catalysts and ionic liquid can be easily recovered and reused.     

Study on mechanism for oxidation of <Emphasis Type="Italic">N,N</Emphasis>-dimethylhydroxylamine by nitrous acid

The oxidation of N,N-dimethylhydroxylamine (DMHAN) by nitrous acid is investigated in perchloric acid and nitric acid medium, respectively. The effects of H⁺, DMHAN, ionic strength and temperature on the reaction are studied. The rate equation in perchloric acid medium has been determined to be −d[HNO₂]/dt = k[DMHAN][HNO₂], where k = 12.8 ± 1.0 (mol/L)⁻¹ min⁻¹ when the temperature is 18.5 °C and the ionic strength is 0.73 mol/L with an activation energy about 41.5 kJ mol⁻¹. The reaction becomes complicated when it is performed in nitric acid medium. When the molarity of HNO₃ is higher than 1.0 mol/L, nitrous acid will be produced via the reaction between nitric acid and DMHAN. The reaction products are analyzed and the reaction mechanism is discussed in this paper.     

果糖在酸性离子液体中脱水制备5-羟甲基糠醛

制备了多种离子液体,并将其作为催化剂和溶剂催化果糖脱水制备5-羟甲基糠醛（HMF）。 制备的酸性离子液体包括磺酸基功能化酸性离子液体、咪唑类酸性离子液体和吡啶类酸性离子液体。 利用核磁共振仪和红外光谱仪对离子液体的结构进行表征。 利用紫外可见光分光光度计结合Hammett指示剂计算Hammett酸度函数,比较了酸强度的大小对反应的影响。 结果表明,离子液体的酸强度对反应有较大影响,在无其它催化剂和溶剂的情况下,离子液体具有较高的催化活性,通过使用1-丁基-3-甲基咪唑氯盐(BmimCl)作为催化剂,当反应温度为120 ℃,反应进行到4 h时,HMF收率可以达到74.97%。     

Effects of ionic liquid as additive and the pH of the mobile phase on the retention factors of amino benzoic acids in RP-HPLC

As an organic salt, ionic liquids are widely used as new solvent media. In this paper, three positional isomers, such as o-amino benzoic acid, m-amino benzoic acid, and p-amino benzoic acid are separated with four different ionic liquids as additives to the mobile phase using reversed-phase (RP) high-performance liquid chromatography (HPLC). Amino benzoic acids are biologically active substances; the p-isomer is present in a group of water-soluble vitamins and is widely known as a sunscreen agent. The ionic liquids used are 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methylsulfate, and 1-octyl-3-methylimidazolium methylsulfate. The effects of the length of the alkyl group on the imidazolium ring and its counterion, the concentrations of the ionic liquid, and the effect of the pH of the mobile phase on the retention factor of the amino benzoic acid isomers are studied. Separation with the ionic liquid in the eluent was better than the separation without the ionic liquid. The pH mainly affected the retention and elution order of the solutes in RP-HPLC.     

Ni2＋的引入对离子液体烷基化催化性能的影响

Thealkylationofisobutanewithbuteneisanim portantprocessforthe productionofhigh qualitypetroleum .In placeofconcentratedsulfuricacid ,Et3NHCl/AlCl3ionicliquidhasbeenusedinthereac tionwithfairlygoodeffect[1] ,butthereisstillabigdifferencecomparedwiththeresultsofconcentratedsulfuricacid .TheC8contentinthealkylatesobtainedwithconcentratedsulfuricacidwas 72 1% [2 ] ,butitwasonly 5 6 %withtheionicliquid .ThekeyreactioninthealkylationishydrogentransferfromC+8toC08[3] ,andthisisthemainreasonforth…     

吗啡啉碱性离子液体催化合成油酸甲酯

采用两步法合成了由阳离子N-甲基-N-丁基吗啡啉和阴离子氢氧根搭配的[Nbmm]OH新型碱性离子液体。实验利用FT-IR、元素分析和TGA分别对该离子液体的化学结构和热稳定性进行了表征。结果表明,该离子液体的热稳定性超过200℃。对该离子液体的溶解性能进行了考察, 结果表明,该离子液体能与强极性溶剂互溶,而且其水溶液的碱性较强。为了考察该离子液体对酯化反应的催化活性,实验过程中以油酸和甲醇反应生成油酸甲酯的酯化反应为模型反应,评价该离子液体的催化活性。结果表明,当反应温度60℃、酸醇比为1:6、离子液体加入量为原料总质量的15%、反应10 h时,油酸转化率达93.9%,而且该离子液体易于从反应体系中分离,可以循环使用。     

Extraction of organic acids by ion-pair formation with tri-n-octylamine : Part. 1. Extraction Rate and Influence of pH and Ionic Strength

The extraction scheme for dyes, developed previously, is applied to benzoic acid and its hydroxylated derivatives. Extractions are done with tri-n-octylamine at pH 5.5 and an ionic strength of 0.1 into chloroform. Equilibrium is attained in 20 min or less. The influences of pH and ionic strength of the extraction medium on the recoveries are described. The scheme developed for dyes is applicable for benzoic acid and salicyclic acid; for more polar acids the pH and ionic strength must be changed in order to maximize the recovery.     

A cautionary note on thermal runaway reactions in mixtures of 1-alkyl-3-methylimidazolium ionic liquids and <Emphasis Type="Italic">N</Emphasis>-methylmorpholine-<Emphasis Type="Italic">N</Emphasis>-oxide

N-Methylmorpholine-N-oxide (NMMO) cannot be completely separated by extraction from mixtures with common 1,3-dialkylimidazolium ionic liquids (ILs) due to strong ionic interactions between the two components. At elevated temperatures, above approx. 90 °C, especially under dry conditions and in the presence of acid, alkylating or acylating agents, remaining NMMO in ILs tends to undergo autocatalytic degradation. This is a highly exothermic, unstoppable process that results in explosions, flames, and complete charring of the reaction mixtures. Thus, caution must be exercised when drying or heating ILs that were in previous contact with NMMO, and the absence of amine oxide must be confirmed to avoid potential danger.     

Novel Brønsted acidic ionic liquids and their use as dual solvent-catalysts

The reaction of triphenylphosphine or N-butylimidazole with cyclic sultones gives zwitterions that are subsequently converted into ionic liquids by reaction with trifluoromethane sulfonic acid or p-toluenesulfonic acid. The resulting ionic liquids have cations to which are tethered alkane sulfonic acid groups. These Br?nsted acidic ionic liquids are useful solvent/catalysts for several organic reactions, including Fischer esterification, alcohol dehydrodimerization and the pinacol rearrangement. The new ionic liquids combine the low volatility and ease of separation from product normally associated with solid acid catalysts, with the higher activity and yields normally found using conventional liquid acids.     

Extraction of trivalent iron in the ionic and colloidal states with Di-n-butylphosphoric acid

The extraction of trivalent iron in the ionic and colloidal states from diluted nitric acid solutions with di-n-butylphosphoric acid in cyclohexane has been studied. Depending on the concentration of di-n-butylphosphoric and nitric acid, the ionic and colloidal trivalent iron can be distributed between the solvent, aqueous phase and solvent-aqueous interface.     

Tetraalkylphosphonium polyoxometalates: electroactive, "task-specific" ionic liquids

The pairing of selected polyoxometalate (POM) anions with appropriate tetraalkylphosphonium cations is shown to yield an original family of ionic liquids, among them an ambient-temperature "liquid POM".     

Dissociation pathways of protic ionic liquid clusters: Alkylammonium nitrates

Protic ionic liquids are promising candidates for many applications, including as spacecraft propellants. For both fundamental interest and understanding clustering and dissociation during electrospray‐based propulsion, it is useful to explore the dissociation pathways of protic ionic liquid clusters, as well as the factors affecting the relative contributions of each pathway to the observed MS/MS spectra. With that said, most of the published reports on ionic liquid cluster dissociation have focused on aprotic ionic liquids. The purpose of the current work is to explore the dissociation pathways (eg, loss of amine, nitric acid, or ion pair) of alkylammonium nitrates using energy‐resolved collision‐induced dissociation. Here, it was found that, in general, protic ionic liquids have multiple dissociation pathways—namely, protic ionic liquids can lose their neutralized cation (here, an alkylamine) or neutralized anion (here, nitric acid)—in addition to the ion pair dissociation familiar to aprotic salt and aprotic ionic liquid clusters. In general, increasing the basicity of the cation (here, through increasing the degree of alkylation) decreases the propensity to follow these alternative pathways. Interestingly, increasing the cluster size has a similar effect: as cluster size increases, nitric acid loss decreases. These results will help better model and design protic ionic liquids for electrospray‐based spacecraft propulsion and help provide a better understanding for the general behavior of protic ionic liquids versus aprotic ionic liquids within mass spectrometers.