Electrodeposition of Aluminum from AlCl3/Et3NHCl Ionic Liquids

Aluminum was successfully electrodeposited on Al electrodes from aluminum chloride (AlCl₃)/triethylamine hydrochloride (Et₃NHCl) ionic liquids by the constant potential electrolysis. Electrical conductivities of AlCl₃/Et₃NHCl ionic liquids were measured as a function of the temperature and composition. The nucleation processes and the influence of experimental conditions on the current efficiency and surface morphology of aluminum electrodeposits were studied on Al electrodes from 2:1 molar ratio AlCl₃/Et₃NHCl ionic liquid. The electrical conductivities of ionic liquids increased as the electrolyte temperature increased, following the Arrhenius behavior. Analyses of the chronoamperograms indicated that the deposition process of aluminum on Al substrates was controlled by instantaneous nucleation with diffusion-controlled growth. Constant potential deposition experiments showed that the electrodeposits obtained on Al electrodes were dense, continuous, and well adherent, and the current efficiency was 73% at −2.4 V(vs Pt) for 20 min electrolysis at room temperature. The purity of aluminum electrodeposits on Al electrodes was above 96% (w).     

Trapping phosphate anions inside the [Ag4I] framework: Structure, bonding, and properties of Ag4I(PO4)

Orange-red Ag₄I(PO₄) crystallizes in the monoclinic system, space group P2₁/m (No. 11), with the unit cell dimensions a=9.0874(6) Å, b=6.8809(5) Å, c=11.1260(7) Å, β=109.450(1)°, and Z=4. The crystal structure is fully ordered; it comprises the silver-iodine three-dimensional positively charged framework hosting the tetrahedral PO₄³⁻ guest anions. The framework features high coordination numbers for iodine and manifold Ag-Ag bonds ranging from 3.01 to 3.46 Å. The Ag-Ag interaction is bonding, it involves silver 4d and 5s orbitals lying, together with the orbitals of iodine, just below the Fermi level. Though the orbitals of silver and iodine define the conducting properties of the title compound, the interaction between the framework and the guest anions is also important and is responsive to the number of the silver atoms surrounding the PO₄³⁻ tetrahedra. Ag₄I(PO₄) melts incongruently at 591 K and produces a mixture of the silver phosphate and an amorphous phase upon cooling. Pure Ag₄I(PO₄) is a poor conductor with a room temperature conductivity of 3×10⁻⁶ S m⁻¹. The discrepancies between the properties observed here and those reported previously in the literature are discussed.     

Fluorination of activated aromatic systems with Selectfluor™ F-TEDA-BF4 in ionic liquids

Selectfluor™ was shown to be soluble in ionic liquid, thus allowing the ‘green’ electrophilic fluorination of activated aromatic systems compounds in high chemoselectivity and yields.     

Synthesis of a Novel Chiral Ionic Liquid and Its Application in Enantioselective Aldol Reactions

A novel chiral ionic liquid, compound 1 , based on camphorsulfonic acid, was prepared. A catalytic amount of 1 readily promotes L ‐proline‐catalyzed aldol reactions, with good chemoselectivity, both in H₂O and in organic solvents. Further, the aldol reaction of cyclohexanone with 4‐nitrobenzaldehyde afforded 2‐[hydroxy(4‐nitrophenyl)methyl]cyclohexanone ( 6 ) in 98% yield with high enantioselectivity (94% ee) when large amounts of 1 (5 equiv.) were used as promoter.     

Charge-tagged polar phosphine ligands in Pd-catalysed reactions in aqueous and ionic media

A new range of polar imidazolium and phosphate-containing ligands was synthesised from readily available starting materials in high yielding multi-step transformations. These ligands were used to generate Pd catalysts for Suzuki and Heck C–C coupling reactions in organic and organic/aqueous media. The catalysts performed well in aqueous media in the Suzuki reaction and less well in the Heck reaction, related to substrate solubility in the aqueous media. When moving to ionic liquids, the Heck reaction dramatically improved, especially in media compatible with the polar catalysts and the non-polar reagents. In all cases, the catalysts were stable to the formation of Pd black, a form of degradation that frequently befalls Pd catalysts. The catalysts could be successfully recycled without loss of activity.     

离子液体液-液萃取-高效液相色谱测定水中酚类化合物

建立了离子液体1-丁基-3-甲基咪唑六氟磷酸盐([C4mim][PF6])液-液萃取-高效液相色谱测定水中酚类化合物的方法.研究了水相pH值、萃取时间、水相体积及盐的浓度对萃取的影响.最佳萃取条件分别为:水相pH值为5,萃取时间为40 min,水相体积为60 mL.对比了离子液体对1-辛醇对苯酚、4-硝基苯酚、2-硝基苯酚、2,4-二甲基苯酚和双酚A的富集效率.在最佳条件下,离子液体对5种酚的富集倍率在9～151之间,方法对苯酚、4-硝基苯酚、2-硝基苯酚、2,4-二甲基苯酚和双酚A的检出限分别为:2.0、0.9、0.3、1.8和1.1 μg/L.将该方法应用于自来水、河水、湖水和污水的检测,回收率为87.9%～109.9%.     

Influence of various series of additives on the clouding behavior of aqueous solutions of triblock copolymers

The cloud point (CP) studies on aqueous solutions of two ethylene oxide-propylene oxide triblock copolymers (EO)_2.5(PO)₃₁(EO)_2.5 and (EO)₁₃(PO)₃₀(EO)₁₃ with varying number of ethylene oxide (EO) units were carried out in the presence of series of additives, such as alkali, acids, ionic surfactants, alcohols, salts, and hydrotropes. The results of this study show that sodium hydroxide decreases the CP of the two copolymers. Acids increase the CP in the order hydrochloric acid > acetic acid > formic acid for both the triblock copolymers. Hydrotropes increase the CP, whereas salts decrease or increase the CP based on their salting-out/salting-in nature. Alcohols, which are polar organic additives, affect the CP of the two copolymers differently. The change in the CP of the triblock copolymers depends upon the structure and concentration of the additives and on the number of EO units of the two triblock copolymers.     

Charge mosaic membranes prepared from laminated structures of PVA-based charged layers: 1. Preparation and transport properties of charged mosaic membranes

A charge mosaic (CM) membrane has high permselectivity for electrolytes. While there are many reports of attempts to prepare such membranes, it is difficult to make CM membranes for practical applications. We report the preparation of CM membranes from laminated structures of charged-poly(vinyl alcohol) (PVA) membranes. The membranes were prepared by alternately stacking negatively charged base membranes and positively charged base membranes and by cutting the stack of charged layers. Permeation experiments were performed in a dialysis system consisting of the membrane and mixed solutions of KCl and sucrose. Although the salt flux through the membrane was about 30 times less than that through the charge mosaic membrane Desalton^® (Tosoh Co. Ltd.), which was prepared using microphase separation, the permselectivity for salt of our membrane is more than 30 times higher than that of Desalton^®.     

Effect of the polarity of silver nanoparticles induced by ionic liquids on facilitated transport for the separation of propylene/propane mixtures

The effect of ionic liquids on the formation of a partial positive charge on the surface of silver nanoparticle and its subsequent effect on facilitated olefin transport were investigated. Three different ionic liquids of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM⁺BF₄⁻), 1-butyl-3-methylimidazolium triflate (BMIM⁺Tf⁻), and 1-butyl-3-methylimidazolium nitrate (BMIM⁺NO₃⁻) were employed to control the positive charge density of the surface of silver nanoparticles. The positive charge density of the silver nanoparticles, as characterized by the binding energy of the silver atom, was in the following order: BMIM⁺BF₄⁻/Ag ? BMIM⁺Tf⁻/Ag > BMIM⁺NO₃⁻/Ag. This order was consistent with the tendency of ionic liquids to form free ions. The best separation performance for the propylene/propane mixtures was a mixed gas selectivity of 17 and a permeance of 7 GPU through a composite membrane consisting of BMIM⁺BF₄⁻/Ag. A better separation performance for olefin/paraffin mixtures was observed with a higher positive charge density of the silver nanoparticles. It was therefore concluded that facilitated olefin transport was a direct consequence of the surface positive charge of the silver nanoparticles induced by ionic liquids.     

含糖聚合物可控合成研究进展

活性聚合技术的进步,使设计合成结构可控的含糖聚合物成为可能.本文介绍了阴离子聚合、阳离子聚合、原子转移自由基聚合、可逆加成断裂链转移聚合、硝基氧介导聚合、开环聚合和开环易位聚合等一系列可控/"活性"聚合技术在合成含糖聚合物中的应用,并对这一领域所取得的研究进展及现状进行了综述.