Electrodeposition of Al,Zn, and Pt on silver-coated textile fibres from ionic liquids

In the present paper, we report on the electrodeposition of aluminium, zinc and platinum on silver-coated textile fibres from ionic liquids. For electrodeposition of Al, the 60:40 mol% mixture of AlCl₃/1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and 1.7 M AlCl₃ in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py_1,4]TFSA) were employed. It was observed that microcrystalline aluminium was electrodeposited on the textile fibres in 60:40 mol% AlCl₃/[EMIm]Cl. The deposited Al layers either on single fibres or on textile assemblies are well adherent and uniform. An adherent, homogeneous and nanocrystalline Al layer was obtained on the silver-coated textile samples from 1.7 M AlCl₃/[Py_1,4]TFSA at 75 °C. The obtained Al layers from 60:40 mol% AlCl₃/[EMIm]Cl on the textile fibres exhibit a good corrosion resistance in an aqueous iodide/iodine electrolyte. Furthermore, we obtain Al microtubes from the investigated ionic liquids after dissolving the textile fibres. In addition, zinc electrodeposition was carried out on the textile samples from 60:40 mol% ZnCl₂/[EMIm]Cl at 80 °C. The electrodeposition of platinum on the textiles was done from 50 mM PtCl₂ in 1-butyl-1-methylpyrrolidinium dicyanamide ([Py_1,4]DCA).     

Electrodeposition of nanocrystalline aluminium from a chloroaluminate ionic liquid

In this letter we show that nanocrystalline aluminium can be electrodeposited in the Lewis acidic ionic liquid based on AlCl₃ (60 mol%) and 1-(2-methoxyethyl)-3-methylimidazolium chloride ([MoeMIm]Cl) (40 mol%). The study comprised cyclic voltammetry, potentiostatic polarization, and SEM and XRD measurements. The methoxy group in the side chain of the imidazolium cation significantly influences the electrodeposition pathway of Al in comparison to [EMIm]Cl/AlCl₃. Cyclic voltammetry shows a significant current loop attributed to nucleation. Shiny Al layers are obtained with an average crystallite size of about 40 nm.     

A new method for practical electrodeposition of aluminium from ionic liquids

Successful electrodeposition of aluminium from ionic liquids has been long achieved scientifically. Nevertheless, standard industrial procedures have not yet been established due to the difficulties associated with using closed system filled with inert gas for the electrodeposition process. This paper presents a new methodology in which electrodeposition of aluminium is conducted in air, after preparation of ionic liquids in a glove box and covering them by a nonwater-absorbable layer of particular organic compound. This compound is stable and shows no reaction with the ionic liquid. Using this new methodology, functional aluminium layers were successfully deposited from a first generation ionic liquid AlCl₃/1-ethyl-3-methylimidazolium chloride – [EMIm]Cl – (60/40 mol%) on low carbon steel. Cyclic voltammetry (CV) measurements revealed that there was no significant difference in electrochemical properties characteristic of Al deposition when conducted in open air. SEM/EDX assessments showed that uniform, dense and adherent Al layers were obtained. Adherence of Al to the steel substrate was improved via in-situ electrochemical etching.     

Electrodeposition of nanocrystalline aluminium, copper, and copper–aluminium alloys from 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ionic liquid

In this paper, we show that nanocrystalline aluminium, copper, and copper–aluminium alloys can be electrodeposited from the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate, [Py_1,4]TfO. Furthermore, Al deposition was studied in 1-ethyl-3-methylimidazolium trifluoromethylsulfonate, [EMIm]TfO for comparison. The two employed ionic liquids exhibit different concentration-dependent phase behaviour with AlCl₃. This study comprises cyclic voltammetry, potentiostatic electrolysis, scanning electron microscopy, X-ray diffraction, atomic absorption spectroscopy, and inductively coupled plasma optical emission spectroscopy. Thick (in micrometre regime) and uniform layers of aluminium deposits were obtained from 2.75?M AlCl₃ in [Py_1,4]TfO at 100?°C. The average crystallite size of aluminium was found to be around 40 to 50?nm. However, a coarse and cubic-shaped Al deposit with crystal sizes in the micrometre regime was obtained from [EMIm]TfO. Electrodeposition of copper was investigated in [Py_1,4]TfO-containing Cu(TfO)₂ at 100?°C. The average grain size of the copper deposit obtained from the electrolysis is around 20 to 40?nm. Electrodeposition of copper–aluminium alloys was successful in the same ionic liquid at 100?°C. Thick layers of copper–aluminium alloys were obtained from the employed ionic liquid. XRD analysis of the obtained deposits from electrolysis experiments revealed that Cu₃Al alloy was formed. SEM analysis indicated that the nanocrystalline copper–aluminium deposits have an average grain size of 60 to 70?nm.     

The “one-pot” synthesis of 2,5-diformylfuran,a promising synthon for organic materials in the conversion of biomass

The organic ionic oxidant 4-acetamido-2,2,6,6-tetramethyl-1-oxopiperidinium tetrafluoroborate, [Pip*(O)][BF₄], was found to be compatible with both classical organic solvents and the ionic liquids [BMIm][Cl]/[BMIm][BF₄] (BMIm is 1-butyl-3-methylimidazolium), which are essential in the conversion of cellulose biomass. A unique NMR monitoring procedure developed in our group was used to study the conversion of fructose to 2,5-diformylfuran in ionic liquids. This process can successfully be carried out in a “one-pot” fashion; [Pip*(O)][BF₄] efficiently oxidizes intermediate 5-hydroxymethylfurfural. The reaction is highly selective, giving 2,5-diformylfuran in 95% yield.     

Metal Assisted Synthesis of Cationic Sulfidobismuth Cubanes in Ionic Liquids

Bi₂S₃ was dissolved in the presence of either AuCl/PtCl₂ or AgCl in the ionic liquids [BMIm]Cl ⋅ xAlCl₃ (BMIm=1-n-butyl-3-methylimidazolium; x=4–4.3) through annealing the mixtures at 180 or 200 °C. Upon cooling to room temperature, orange, air-sensitive crystals of [BMIm](Bi₄S₄)[AlCl₄]₅ ( 1 ) or Ag(Bi₇S₈)[S(AlCl₃)₃]₂[AlCl₄]₂ ( 2 ) precipitated, respectively. 1 did not form in the absence of AuCl/PtCl₂, suggesting an essential role of the metal cations. X-ray diffraction on single-crystals of 1 revealed a monoclinic crystal structure that contains (Bi₄S₄)⁴⁺ heterocubanes and [AlCl₄]⁻ tetrahedra as well as [BMIm]⁺ cations. The intercalation of the ionic liquid was confirmed via solid state NMR spectroscopy, revealing unusual coupling behavior. The crystal structure of 2 consists of (Bi₇S₈)⁵⁺ spiro-dicubanes, [S(AlCl₃)₃]²⁻ tetrahedra triples, isolated [AlCl₄]⁻ tetrahedra, and heavily disordered silver(I) cations. No cation ordering took place in 2 upon slow cooling to 100 K.     

Challenges in the electrochemical coating of high-strength steel screws by aluminum in an acidic ionic liquid composed of 1-Ethyl-3-methylimidazolium chloride and AlCl3

In this paper we show that screws made of high-strength steel (12.9 grade) can, in principle, be electrochemically coated with up to 40-μm-thick Al layers in an ionic liquid composed of 1-Ethyl-3-methylimidazolium chloride and AlCl₃ (40/60 mol%). The main challenge for the adhesive deposition of Al is a thorough purification and pretreatment of the screws prior to Al deposition. It is shown that a combination of degreasing, etching, plasma treatment, and electrochemical etching in the ionic liquid is a prerequisite for an adhesive and well protecting Al layer. Even then it can happen that at some sites Al does not adhere sufficiently well. A proper posttreatment is essential, too, and we show that the ionic liquid must be removed with another ionic liquid prior to a chemical passivation in boiling distilled water to get a high layer quality.     

Ionothermal Synthesis of Sulfidobismuth spiro-Dicubane Cations

Bi₂S₃ was dissolved in the presence of NaCl in the ionic liquid [BMIm]Cl ⋅ 4AlCl₃ (BMIm=1-n-butyl-3-methylimidazolium) through annealing the mixture at 180 °C. Upon cooling to room temperature, orange, air-sensitive crystals of Na(Bi₇S₈)[S(AlCl₃)₃]₂[AlCl₄]₂ ( 1 ) precipitated. X-ray diffraction on single-crystals of 1 revealed a triclinic crystal structure that contains (Bi₇S₈)⁵⁺ spiro-dicubanes, [S(AlCl₃)₃]²⁻ tetrahedra triples, isolated [AlCl₄]⁻ tetrahedra, and sodium cations.     

Al electroplating on the AZ121 Mg alloy in an EMIC–AlCl3 ionic liquid containing ethylene glycol

To improve the corrosion resistance of Mg alloys, an Al layer was electrodeposited on the Mg surface from an ionic liquid of 1-ethyl-3-methylimidazolium chloride (EMIC) and aluminum chloride (AlCl₃) at 283?K. A smooth surfaced Al electrodeposit can be electroplated in the AlCl₃–EMIC ionic liquid by pulse electrolysis at 6.7?Hz and a duty ratio of 0.67. A denser and flatter Al layer was successfully electroplated on AZ121 substrate at the lower temperature of 283?K in an AlCl₃–EMIC ionic liquid with 0.1?M ethylene glycol added.     

Application of chloroaluminate ionic liquid as catalyst and medium for the dealkylation of esters

Abstract  

Dealkylation of esters to carboxylic acids was performed using chloroaluminate ionic liquids (PyHBr/AlCl₃, PyHCl/AlCl₃, Me₃NHCl/AlCl₃, Et₃NHCl/AlCl₃) as catalyst and medium. The catalytic activity of PyHBr/AlCl₃ (X(AlCl₃) = 0.67) proved to be superior to the other three ionic liquids for the dealkylation of methyl benzoate with a conversion of 97% after 3 h at 140 °C. After easy separation from the products the ionic liquid PyHBr/AlCl₃ could be reused six times without loss of its activity.     

Measurement and modeling of osmotic coefficients of aqueous solution of ionic liquids using vapor pressure osmometry method

Osmotic coefficients of binary mixtures containing an ionic liquid, (1-butyl-3-methylimidazolium tetrafluoroborate, [BMIm]BF₄, 1-ethyl-3-methylimidazolium ethyl sulfate, [EMIm]ES, and 1-butyl-3-methylimidazolium methyl sulfate, [BMIm]MS) with water were measured until about 3 molal concentrations using vapor pressure osmometry method (VPO) at temperature ranges 298.15–328.15 K and modeled using different electrolyte excess Gibbs free energy models including electrolyte non-random two liquids (NRTL), modified NRTL (MNRTL), mean spherical approximation NRTL (MSA-NRTL), non random factor (NRF), and extended Wilson models. The results show that osmotic coefficient data increase with increasing temperature. The calculated standard deviations of the studied systems show that the applicability of these models for the correlation of VLE properties of ionic liquid solutions. The average standard deviations for the models have the order σ(?) MNRTL < σ(?) Wilson < σ(?) NRTL < σ(?) MSA-NRTL < σ(?)NRF. The results show MNRTL model is able to reproduce experimental osmotic coefficients of aqueous solution of studied ionic liquids with good precision.     

Iridium-catalyzed regiospecific allylation of dimethyl malonate in ionic liquids

Allylation of dimethyl malonate with 1-(4-chlorophenyl)prop-2-enyl methyl carbonate in the presence of [Pd(All)Cl]₂, [Rh(COD)Cl]₂, [Ir(COD)Cl]₂ (COD is cycloocta-1,5-diene), and a chiral ferrocenyl-containing phosphite ligand based on (R)-BINOL (BINOL is 2,2′-dihydroxy-1,1′-binaphthyl) in CH₂Cl₂ gave a mixture of linear and branched cross-coupling products, the latter having a moderate optical purity (below 51%). The rhodium-and iridium-catalyzed reactions were very highly regioselective (regiospecific in the case of Ir), giving a branched product. In ionic liquids ([bmim][BF₄] and [bdmim][BF₄]) (bmim is 1-butyl-3-methylimidazolium and bdmim is 1-butyl-2,3-dimethylimidazolium), the Ir-catalyzed reaction regiospecifically afforded a branched product as a racemate. The same result was obtained with [Ir(COD)Cl]₂ as a catalyst; this reaction easily occurred in ionic liquids even without a base. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 519–521, March, 2007.     

Dramatic Change in Viscosities of Pure Ionic Liquids upon Addition of Molecular Solvents

Viscosities of binary mixtures of pyridinium based ionic liquids (1-butyl pyridinium tetrafluoroborate, [BP][BF₄], 1-butyl 3-methyl pyridinium tetrafluoroborate [3-MBP][BF₄], 1-butyl 4-methyl pyridinium tetrafluoroborate, [4-MBP][BF₄]), and phosphonium based ionic liquids, (tetrabutyl phosphonium alaninate, [TBP][Ala]; tetrabutyl phosphonium valinate, [TBP][Val]) with the molecular solvents, water, methanol and dichloromethane, have been measured at 298.15 K. A Brookfield ultra-rheometer was employed to measure the reported viscosities. The drop in viscosity in the close vicinity of pure ionic liquid is more prominent in polar solvents like water compared to less polar solvents. The temperature dependence of this observation was also studied for binary mixtures of [4-MBP][BF₄] with water in range of 298.15–323.15 K. The Vogel-Fulcher-Tamman (VFT) equation was employed to investigate the temperature dependence of the viscosities of pure pyridinium-based ionic liquids in the temperature range from 298.15–323.15 K.     

AlCl<Subscript>3</Subscript>/amide ionic liquids for electrodeposition of aluminum

AlCl₃/amide (acetamide, propionamide, butyramide) ionic liquids were used as the electrolytes to study the electrodeposition behavior of aluminum on a tungsten electrode. Cyclic voltammograms on the tungsten electrode indicate that Al(III) ions can be reduced to aluminum only within the molar ratio range of 1.1 to 1.5 and the reduction potentials of Al(III) ions strongly depend on the molar ratio of AlCl₃/amide. Raman spectra results reveal that the electroactive specie of AlCl₃/amide ionic liquids is Al₂Cl₇ ^?. Aluminum coatings were prepared at ?0.25 V (vs. Al/Al³⁺) and at 313 K in AlCl₃/amide ionic liquids with the molar ratio of 1.3. The SEM and cross-sectional SEM images show that all the obtained aluminum films are silver-colored, thick, and adherent. The EDS and XRD analysis confirm that the obtained deposits are pure aluminum. The present results can provide a new route for aluminum electrodeposition under ambient conditions.     

Study on the Conductivities of Pure and Aqueous Bromide-Based Ionic Liquids at Different Temperatures

Electrical conductivities were measured for the pure ionic liquids [C₆mim][Br] (1-hexyl-3-methylimidazolium bromide) and [C₈mim][Br] (1-octyl-3-methylimidazolium bromide) at 0.1 MPa from 293.15 to 333.15 K. Conductivity measurements were also made for the binary water + [C₆mim][Br] and water + [C₈mim][Br] systems and their ternary water + [C₆mim][Br] + [C₈mim][Br] system at 0.1 MPa and 293.15, 298.15, and 303.15 K. The conductivity data of the pure ionic liquids were correlated by the VFT (Vogel-Tamman-Fulcher) equation, and the fitting parameters and mean absolute deviations were determined. New explanations are presented for the molality-dependent behavior of the conductivity of the binary water + [C₆mim][Br] and water + [C₈mim][Br] systems. The generalized Young’s rule and the semi-ideal solution theory for conductivity were used to predict the conductivities of the ternary water + [C₆mim][Br] + [C₈mim][Br] system from the conductivities of its corresponding binary water + [C₆mim][Br] and water + [C₈mim][Br] subsystems. The predictions are in good agreement with the measured values.     

Thermal behavior of α-(Cu–Al–Ag) alloys

Thermal behavior of α-(Cu–Al–Ag) alloys, i.e. alloys with composition less than about 8.5 mass% Al, was studied using differential scanning calorimetry (DSC), differential thermal analysis (DTA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results indicated that the presence of silver introduces new thermal events ascribed to the formation of a silver-rich phase and, after addition higher amounts than 8 mass% Ag to the Cu–8 mass% Al alloy it is possible to observe the formation of the γ₁ phase (Al₄Cu₉), which is only observed in alloys containing minimum of 9 mass% Al. These results may be attributed to some Ag characteristics and its interaction with Cu and Al.     

Electrochemical characterization of common catalysts and initiators for atom transfer radical polymerization in [BMIm][OTf]

The redox properties of some largely employed ATRP initiators and copper catalysts (Cu/L/X⁻) were investigated in 1-butyl-3-methylimidazolium trifluoromethanesulfonate (L = amine ligand, X = Br or Cl). Both Cu(II) and Cu(I) complexes are stable in the IL and, as required by ATRP, X⁻ stabilizes more Cu(II) than Cu(I). The activation rate constants of initiators by [Cu^ITPMA]⁺ were measured and a good correlation between k_act and the C-X bond dissociation free energy (BDFE) was observed. Overall, the results indicated that [BMIm][OTf] behaves much like organic solvents; the reported data launch the bases for a useful database to select the appropriate catalyst/initiator couple for ATRP in ILs.     

Transformations of xylenes in trimethylammonium hydrochloride—Aluminum chloride ionic liquid

Isomerization of m-, o-and p-xylenes in the presence of trimethylammonium hydrochloride-AlCl₃ ionic liquid with different composition was studied. Ionic liquids with the following ammonium salt: AlCl₃ molar ratios were used: 1∶2, 1∶1.5 and 1∶1.25. It was shown that isomerization of xylenes proceeds under mild conditions at temperatures from 60°C to 110°C. It was found that the activity and selectivity of the ionic liquids depends on their composition. The most effective catalyst was the ionic liquid with the ammonium salt: AlCl₃ molar ratio equal to 1∶2.     

Biphasic ethylene polymerisation using ionic liquid over a titanocene catalyst activated by an alkyl aluminium compound

1-n-Butyl-3-methylimidazolium tetrachloroaluminate ([BMIM]⁺[AlCl₄]⁻) was applied to biphasic ionic liquid/hexane ethylene polymerisation as a medium of the Cp₂TiCl₂ titanocene catalyst activated by alkylaluminium compounds (MAO, AlEt₂Cl, AlEt₃). The best results were obtained using AlEt₂Cl. The results show that catalyst recycling, higher ethylene pressure, and greater Al/Ti molar ratio along with a greater volume of the ionic liquid phase enhance catalyst activity. The polyethylene gathered from the hexane phase is characterised primarily by its high purity. Its physical properties remain polyethylene obtained over a heterogeneous metallocene catalyst. Thus, biphasic ionic liquid polymerisation using a metallocene catalyst is possible and offers interesting technological implications.