离子液体复配溶剂体系改进壬二酸的合成工艺

以油酸为原料,50%的H2O2为氧化剂,在离子液体作为主要溶剂的条件下,采用钨酸为催化剂所得中间产物用自制的过氧乙酸继续氧化裂解合成了高纯度壬二酸。其中分别对异丙醇、离子液体(BMIMPF6和BMIMBF4)单独作溶剂以及二者复配作溶剂的各种情况作了详细比较。最终经过收率、熔点、FT-IR及HPGC等手段将对上述各产物品质进行了表征与分析,从而得出了合成壬二酸的最佳条件为n(C18H34O2)∶n(H2O2)∶n(H2WO4)=1.0∶3.0∶0.04,V(BMIMPF6)∶V(isopropanol)=1∶0.7,所得中间产物中加入300mL含量为25%的过乙酸在90℃氧化裂解3h。最终壬二酸收率可达46%,纯度高于95%。     

Colloidal gold immobilized on mesoporous silica as a highly active and selective catalyst for styrene epoxidation with H2O2

Colloidal gold nanoparticles were synthesized by different procedures affording suspensions with two different mean sizes (2 and 5 nm). Au catalysts were prepared by sol immobilization onto several silica frameworks with different 2D and 3D mesoporosities. The catalysts were tested in styrene oxidation reactions showing excellent efficiency and selectivity. The effect of nanoparticle size and mesoporous framework on the physical and catalytic properties of the final materials was studied. The most selective catalyst was prepared from the 5 nm Au nanoparticles and the more interconnected silica framework (3D mesoporosity).     

离子液体体系制备高分散碳载Pt催化剂

用离子液体做溶剂制备碳载Pt催化剂,透射电镜结果表明,用离子液体做溶剂制备的催化剂Pt/C(A),活性组分Pt粒径小,分散的非常均匀。用这种方法制备的Pt/C(A)催化剂对乙二醇的阳极电氧化具有很高的电催化活性和稳定性。     

Hybrid peroxotungstophosphate organized catalysts highly active and selective in alkene epoxidation

Heterogenization of homogeneous catalysts is still a challenge but can improve drastically the processability of these compounds. Hybridization of polyoxometalates offers an efficient heterogenization route of homogeneous epoxidation catalysts. The Keggin [PW₁₂O₄₀]^3 − and the Ventruello {PO₄[WO(O₂)₂]₄}^3 − species were inserted by electrostatic interactions in a poly(ampholytic) polymeric matrix in order to prevent the leaching of these species. The presence of the polymeric matrix allows to tune the catalyst performance in cyclooctene epoxidation and to improve the selectivity to epoxide. Indeed, the hydrophobicity of the matrix induces a quick desorption of hydrophilic epoxide species. Their over-oxidation and the catalyst species deactivation by over-adsorption of epoxide are then avoided.     

Supported copper oxide as a highly active/selective catalyst for the epoxidation of styrene by TBHP to styrene oxide

Liquid phase epoxidation of styrene by anhydrous and aqueous TBHP to styrene oxide has been studied under reflux, using different supported CuO (viz. CuO/Si-MCM-41, CuO/Al₂O₃, CuO/Ga₂O₃ and CuO/In₂O₃) as easily separable and reusable heterogeneous catalysts. The CuO/Ga₂O₃ catalyst showed the best performance in the epoxidation by aqueous TBHP. The CuO supported on In₂O₃ or Si-MCM-41 also showed very good performance in the epoxidation but only by anhydrous TBHP. However, the CuO/SiO₂ catalyst, however, showed very good performance in the epoxidation by both the anhydrous and aqueous TBHP. Influence of the reaction conditions (temperature, time and TBHP/styrene ratio) on the epoxidation by aqueous TBHP over the best catalyst (CuO/Ga₂O₃) has been investigated.     

离子液体溶解牛骨工艺条件研究

以牛骨为原料,利用1-乙基-3-甲基溴代咪唑([Emim]Br)离子液体进行溶解。分析实验中固液比(牛骨与离子液体质量比)、溶解温度、溶解时间对牛骨溶解率的影响,设计了单因素实验和正交实验。骨粉溶解率随溶解温度的升高、溶解时间的增长而增加,但在不同固液比下溶解率在某一范围波动;离子液体溶解牛骨的最佳工艺参数为:溶解时间为7 h,溶解时固液比为1∶10(g∶g),溶解温度为230℃。利用红外光谱对120℃下溶解牛骨得到的产物进行分析,判定产物为再生胶原和牛骨羟基磷灰石,初步判定该溶解工艺可以同时分离得到有机物和无机物组分。     

离子液体溶解牛骨工艺条件研究

以牛骨为原料,利用1-乙基-3-甲基溴代咪唑([Emim]Br)离子液体进行溶解。分析实验中固液比(牛骨与离子液体质量比)、溶解温度、溶解时间对牛骨溶解率的影响,设计了单因素实验和正交实验。骨粉溶解率随溶解温度的升高、溶解时间的增长而增加,但在不同固液比下溶解率在某一范围波动;离子液体溶解牛骨的最佳工艺参数为:溶解时间为7 h,溶解时固液比为1∶10(g∶g),溶解温度为230℃。利用红外光谱对120℃下溶解牛骨得到的产物进行分析,判定产物为再生胶原和牛骨羟基磷灰石,初步判定该溶解工艺可以同时分离得到有机物和无机物组分。     

The functionalized ionic liquid-stabilized palladium nanoparticles catalyzed selective hydrogenation in ionic liquid

The functionalized ionic liquid (2,3-dimethyl-1-[3-N,N-bis(2-pyridyl)-propylamido] imidazolium hexafluorophosphate, [BMMDPA][PF₆]) stabilized and modified palladium nanoparticles were obtained by reducing palladium(II) complex with molecular hydrogen. The as-synthesized palladium nanoparticles have been characterized by different methods. It was demonstrated that the Pd nanoparticles were very efficient catalysts for the selective hydrogenation of the CC bonds of various functionalized alkenes under mild conditions in neat ionic liquid (1-n-butyl-2,3-dimethylimidazolium hexafluorophosphate, [BMMIM][PF₆]). An efficient separation of the products from reaction mixture (ionic liquid phase) was realized and the catalyst’s nano-dispersion and high performance could be preserved.     

高活性离子液体催化酯化反应的研究

制备了4种吡啶、三乙胺类水溶性离子液体,考察了其催化制备油酸乙酯的活性。结果表明,这4种离子液体催化活性很高,在醇酸摩尔比6∶1,反应温度77℃,反应时间6 h,催化剂用量8%反应条件下,乙基吡啶硫酸氢盐活性最高,酯化转化率可达95.9%;在催化混合脂肪酸的酯化反应中,4种离子液体均表现出较高活性,酯化转化率均高于94%,且离子液体稳定性好,可循环使用。     

Polyethylene glycol-supported ionic liquid as a highly efficient catalyst for the synthesis of propylene carbonate under mild conditions

The coupling reaction of propylene and CO₂ to form propylene carbonate (PC) was promoted by an ionic liquid (IL) covalently bound to polyethylene glycol (PEG). The supported ionic liquid, which has both acidic and basic components, proved to be an active catalyst for PC synthesis under mild conditions. The effects of different cations and anions, reaction temperature, CO₂ pressure, and reaction time were investigated. It was demonstrated that the acid group in the catalyst plays an important role in the reaction. With this system, a high PC yield (95%) was achieved under mild conditions (3.0 MPa, 120°C and 4 h) without a co-solvent. In addition, the catalyst was readily recovered and reused. Based on the experimental results, a plausible mechanism for the catalyst was proposed.     

丝素蛋白在离子液体中的溶解特性研究

文章以离子液体为溶剂,研究了丝素蛋白在离子液体中的溶解特性。首先研究了丝素蛋白在不同结构的离子液体1-烯丙基-3-甲基咪唑氯化物（[AMIM]C1）和1-丁基-3_-甲基咪唑氯化物（[BMIM]c1）中的溶解速率和溶解度。结果发现,相同条件下,丝素蛋白在[AMIM]cl中具有较快的溶解速率和较大的溶解度;随温度的升高,溶解速度加快,合适的温度为95～105℃;随着丝素蛋白浓度的增大,相同条件下丝素蛋白在离子液体中的溶解速度减慢。XRD结果表明,丝素蛋白的非晶相部分首先被溶解,晶相部分结构被破坏后与溶剂作用逐渐被溶解。采用粘度法测定了丝素蛋白分子质量随溶解时间和温度的变化,结果表明：随加热时间增加和温度升高,蛋白质分子质量减小。为保证丝素蛋白的稳定性和溶解速率,温度一般控制在100℃以下,溶解时间小于5h。     

Effect of solvent on ionic liquid dissolved regenerated antheraea assamensis silk fibroin

We report on the dissolution of semi‐domestic silk type Antheraea assamensis using ionic liquids. We investigated the impact of different coagulating solvents, including isopropanol and water on the structure and the morphology of the regenerated silk. We found that the water regenerated silk film showed a high β‐sheet content and a native silk‐like XRD pattern. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A highly selective electrochemical biosensor for Hg using hemin as a redox indicator

A highly selective electrochemical biosensor for the detection of Hg²⁺ in aqueous solution has been developed. This sensor is based on the strong and specific binding of Hg²⁺ by two DNA thymine bases (T–Hg²⁺–T). The hemin worked as a redox indicator to generate a readable electrochemical signal. Short oligonucleotide strands containing 5 thymine (T₅) were used as probe. Thiolated T₅ strands were self-assembled through Au–S bonding on gold electrode. In the presence of Hg²⁺, the specific coordination between Hg²⁺ and thymine bases resulted in more stable and porous arrangement of oligonucleotide strands, so hemin could be adsorbed on the surface of gold electrode and produced an electrochemical signal, which was monitored by differential pulse voltammetry (DPV). The DPV showed a linear correlation between the signal and the concentration of Hg²⁺ over the range 0–2 μM (R² = 0.9983) with a detection limit of 50 nM. The length of probe DNA had no significant impact on the sensor performance. This electrochemical biosensor could be widely used for selective detection of Hg²⁺.     

Highly selective and efficient transport of toluene in bulk ionic liquid membranes containing Ag as carrier

Ionic liquids have very low vapour pressure and a very high boiling temperature and are therefore a potentially environmentally friendly solvent. In this paper, room-temperature ionic liquids are used as a bulk liquid membrane for separation of toluene from n-heptane. Aromatic hydrocarbon, toluene, is successfully transported through the ionic liquid membrane based on 1-methyl-3-octyl imidazolium chloride. Using silver ion as a carrier in 1-methyl-3-octyl imidazolium chloride membranes, batch wise extraction experiments are carried out. The separation performances, represented by the permeation rate and separation factor, are analyzed systematically by varying the operating parameters: the contact time, concentration of Ag⁺, stirring effect, initial feed phase concentration and temperature.     

Glycine hydrochloride ionic liquid/aqueous solution system as a platform for the utilization of chitosan

Glycine hydrochloride ([Gly]Cl), a room‐temperature ionic liquid (IL), is proposed as a new, good solvent for chitosan with different deacetylation degrees and molecular weights. However, considered from the viscosity of a solution of chitosan and [Gly]Cl, a 2% [Gly]Cl IL aqueous solution was selected as an optimum solvent system for dissolving chitosan. X‐ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to visualize the modifications of the native structures of chitosan during the dissolution and the regeneration processes, morphological features, and properties of the reconstituted chitosan membranes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

ARGET ATRP of acrylonitrile with ionic liquid as reaction medium and FeBr3/isophthalic acid as catalyst system

Atom transfer radical polymerization using activators regenerated by electron transfer (ARGET ATRP) of acrylonitrile with FeBr₃ and isophthalic acid (IA) as catalyst and ligand, ascorbic acid (VC) as reducing agent, and ethyl 2‐bromoisobutyrate as initiator was approached for the first time in the presence of air in 1‐dodecyl‐3‐methylimidazolium tetrafluoroborate ([C₁₂mim][BF₄]), 1‐octyl‐3‐methylimidazolium tetrafluoroborate ([C₈mim][BF₄]), and 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C₄mim][BF₄]). The rate of polymerization in [C₁₂mim][BF₄] was considerably faster than in [C₈mim][BF₄] and [C₄mim][BF₄]. With an increase of VC concentration, both the monomer conversion and the molecular weight distribution showed a trend of increase. Polyacrylonitrile (PAN) with higher molecular weight at 166,250 and broader distribution at 1.34 was successfully prepared with PAN as macroinitiator via ARGET ATRP in [C₁₂mim][BF₄] in the presence of air. The resultant polyacrylonitrile fibers were obtained with the fineness at 1.15 dtex and the tenacity at 6.24 cN dtex^?1. Additionally, it was shown that [C₁₂mim][BF₄] could be recycled and reused after simple purification and had no effect on the living nature of polymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Efficient epoxidation of alkenes with sodium periodate catalyzed by manganese porphyrins in ionic liquid: Investigation of catalyst reusability

In the present work, efficient epoxidation of alkenes with sodium periodate catalyzed by tetraphenylporphyrinatomanganese(III) chloride, Mn(TPP)Cl, and octabromotetraphenylporphyrinatomanganese(III) chloride, Mn(Br₈TPP)Cl, using (1-n-butyl-3-methylimidazolium tetrafluoroborate), [bmim][BF₄], as ionic liquid is reported. The effect of substituted bromines on the catalytic activity and reusability of manganese porphyrins was also investigated.     

Selective propylene epoxidation in liquid phase using highly dispersed Nb catalysts incorporated in mesoporous silicates

Selective propylene epoxidation to propylene oxide(PO) with hydrogen peroxide(H_2O_2) was carried out in a catalytic semi-batch reactor.High propylene epoxidation activity(44 h~(-1)) was observed over Nb based mesoporous silicate materials Nb-TUD-1 under mild operating conditions.The physical and chemical properties of the Nb based silicates characterized using BET,FTIR,TPD,TEM and UV–Vis revealed that the site isolation and surface acidity are crucial for PO production.Catalyst synthesis methods were investigated for their effects on PO productivity,PO selectivity and H_2O_2 utilization efficiency.It is found that Nb-TUD-1 material synthesized by the sol–gel method is more active and selective than impregnated materials for liquid phase propylene epoxidation.Surface characterization confirms that thus synthesized Nb-TUD-1 catalysts have more Lewis acidity and less Bronsted acidity compared to the catalysts by impregnation.     

Electrosyntheses of free-standing and highly conducting polyselenophene films in an ionic liquid

The electrochemical polymerization of selenophene in a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF₆) led to the formation of free-standing and highly conducting polyselenophene (PSe) films with an electrical conductivity as high as 2.3 S/cm, higher than PSe electrodeposited in conventional media. The polymerization rate was significantly improved as BmimPF₆ served as both the growth medium and an electrolyte. PSe showed good electroactivity and stability even in concentrated sulfuric acid. Infrared (IR) spectra confirmed the polymerization mainly through α-α′ coupling. Scanning electron microscopy results indicated the formation of smooth and compact PSe films.