Acceleration of diffusion in ethylammonium nitrate ionic liquid confined between parallel glass plates

The bulk self diffusion of the ethylammonium cation and the nitrate anion can both be described by respective single diffusion coefficients. Diffusion of the anion is 1.7 times higher than that of the cation. This indicates no tight association of the ions in the ionic liquid. For the ethylammonium cation confined between glass plates the effective diffusion coefficient along, as well as normal to the confining glass plates is higher by a factor of 1.86 as compared to that in the bulk. The same time, NMR T2 relaxation of protons of NH3 group of the EA cation is faster by a factor of 22 than that in bulk. 2H NMR spectra of selectively labeled CH2 and CH3 groups of EA do not demonstrate any ordering of the EA between the glass plates. We suggested that these data favor a model where a bulk isotropic sponge like structure of EAN is saved in the confinement, but sizes of connecting channels increases. Those leads to faster translational diffusion and faster exchange processes of protons of NH3 group, in comparison with the bulk.Comment: 11 pages, 5 figures, 1 tabl

Influence of Alzheimer's β-amyloid peptide on the lateral diffusion of lipids in raft-forming bilayers

The effect of added Alzheimer's Aβ(1-40) peptide of the wild type on the lateral diffusion of lipids in macroscopically oriented bilayers of 'raft' compositions [a mixture of dioleoylphosphatidylcholine (DOPC), sphingomyelin (SM) and cholesterol (CHOL)] was studied by an NMR-diffusion technique. In homogeneous bilayers, diffusion coefficients decrease, while they change differently in liquid ordered and in liquid disordered phases at varied concentrations of CHOL; this was explained by the decreased maximum solubility of CHOL in phospholipids in the presence of Aβ(1-40) peptide. © 2013 Mendeleev Communications. All rights reserved

The Surface Properties of Aqueous Fluorapatite & Maghemite with Reference to the Dephorization of Magnetite

The Luossavaara-Kirunavaara AB(LKAB) in northern Sweden is one of the biggest suppliers in the world of high grade iron ore products. However, the Kiruna magnetite ore deposit contains an average of 1 wt% phosphorus (mainly fluorapatite), which is detrimental to the blast-furnace technology and the quality of the iron products. Conseque-ntly the apatite content has to be minimized. After magne-tic separation the dephosphorization is performed by froth flotation of the apatite from magnetite fines using a fatty acid type collector (ATRAC)in a combination with sodium silicate. The concentrated magnetite fines are then treated in a pelletizing plant

Diffusion of ions in phosphonium orthoborate ionic liquids studied by 1H and 11B pulsed field gradient NMR

Non-halogenated boron-based ionic liquids (ILs) composed of phosphonium cations and chelated orthoborate anions have high hydrolytic stability, low melting point and exceptional properties for various applications. This study is focused on ILs with the same type of cation, trihexyltetradecylphosphonium ([P-6,P-6,P-6,P-14](+)), and two orthoborate anions, such as bis(salicylato)borate ([BScB](-)) and bis(oxalato)borate ([BOB](-)). We compare the results of this study with our previous studies on ILs with bis(mandelato)borate ([BMB](-)) and a variety of different cations (tetraalkylphosphonium, dialkylpyrrolidinium and dialkylimidazolium). The ion dynamics and phase behavior of these ILs is studied using H-1 and B-11 pulsed-field-gradient (PFG) NMR. PFG NMR is demonstrated to be a useful tool to elucidate the dynamics of ions in this class of phosphonium orthoborate ILs. In particular, the applicability of B-11 PFG NMR for studying anions without H-1, such as [BOB](-), and the limitations of this technique to measure self-diffusion of ions in ILs are demonstrated and discussed in detail for the first time

Adsorption of butanol and water vapors in silicalite-1 films with a low defect density

Pure silica zeolites are potentially hydrophobic and have therefore been considered to be interesting candidates for separating alcohols, e.g., 1-butanol, from water. Zeolites are traditionally synthesized at high pH, leading to the formation of intracrystalline defects in the form of silanol defects in the framework. These silanol groups introduce polar adsorption sites into the framework, potentially reducing the adsorption selectivity toward alcohols in alcohol/water mixtures. In contrast, zeolites prepared at neutral pH using the fluoride route contain significantly fewer defects. Such crystals should show a much higher butanol/water selectivity than crystals prepared in traditional hydroxide (OH–) media. Moreover, silanol groups are present at the external surface of the zeolite crystals; therefore, minimizing the external surface of the studied adsorbent is important. In this work, we determine adsorption isotherms of 1-butanol and water in silicalite-1 films prepared in a fluoride (F–) medium using in situ attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy. This film was composed of well intergrown, plate-shaped b-oriented crystals, resulting in a low external area. Single-component adsorption isotherms of 1-butanol and water were determined in the temperature range of 35–80 °C. The 1-butanol isotherms were typical for an adsorbate showing a high affinity for a microporous material and a large increase in the amount adsorbed at low partial pressures of 1-butanol. The Langmuir–Freundlich model was successfully fitted to the 1-butanol isotherms, and the heat of adsorption was determined. Water showed a very low affinity for the adsorbent, and the amounts adsorbed were very similar to previous reports for large silicalite-1 crystals prepared in a fluoride medium. The sample also adsorbed much less water than did a reference silicalite-1(OH–) film containing a high density of internal defects.The results show that silicalite-1 films prepared in a F– medium with a low density of defects and external area are very promising for the selective recovery of 1-butanol from aqueous solutions

Halogen-free pyrrolidinium bis(mandelato)borate ionic liquids : some physicochemical properties and lubrication performance as additives to polyethylene glycol

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