Proton conductivity of composites based on Nafion and silica matrices with a chemically modified surface

The surface of aerosilogel and macroporous and microporous glasses was modified with aromatic sulfo groups (≡Si(CH₂)₂-C₆H₄-SO₃H) by the chemical assembly method. Composite solid electrolytes containing Nafion were prepared from the silica matrices with a chemically modified surface. The proton conductivity of the materials was studied by impedance spectroscopy. Composite materials based on Nafion and aerosilogel matrices and macroporous glasses with grafted ≡Si(CH₂)₂-C₆H₄-SO₃H groups showed the highest proton conductivity.     

Chemical transformations of methane in trifluoroacetic acid

The reaction of methane conversion in anhydrous trifluoroacetic acid (TFA) is shown to take place at room temperature and atmospheric pressure and to result in the formation of a resinous product. Signals of ions with molecular weights of 684 and 700 are observed in MALDI-TOF spectra of the dry residue of methane conversion products.     

Reaction of 2-Chloropyridine-3,4-dicarbonitrile with Anilines. Synthesis of 2-(Arylamino)pyridine-3,4-dicarbonitriles

Russian Journal of Organic Chemistry - The reaction of 2-chloropyridine-3,4-dicarbonitrile with anilines in propan-2-ol in the presence of N,N- diisopropylethylamine (DIPEA) in a sealed vial at...     

Coercivity of Combined Boundary Integral Equations in High‐Frequency Scattering

We prove that the standard second‐kind integral equation formulation of the exterior Dirichlet problem for the Helmholtz equation is coercive (i.e., sign‐definite) for all smooth convex domains when the wavenumber k is sufficiently large. (This integral equation involves the so‐called combined potential, or combined field, operator.) This coercivity result yields k‐explicit error estimates when the integral equation is solved using the Galerkin method, regardless of the particular approximation space used (and thus these error estimates apply to several hybrid numerical‐asymptotic methods developed recently). Coercivity also gives k‐explicit bounds on the number of GMRES iterations needed to achieve a prescribed accuracy when the integral equation is solved using the Galerkin method with standard piecewise‐polynomial subspaces. The coercivity result is obtained by using identities for the Helmholtz equation originally introduced by Morawetz in her work on the local energy decay of solutions to the wave equation. © 2015 Wiley Periodicals, Inc.     

A study of n-dodecylammonium acrylamido-2-methylpropanesulfonate association in aqueous solutions

Association of a micelle-forming monomer, n-dodecylammonium 2-acrylamido-2-methylpropanesulfonate, in aqueous solutions has been studied in a concentration range of 1.5 × 10^?3–2.5 × 10^?1 M with the use of conductometry, capillary and rotational viscometry, isothermal translational diffusion, and atomic force microscopy. Two critical micelle concentrations have been determined, and the shape of n-dodecylammonium 2-acrylamido-2-methylpropanesulfonate micelles has been proposed.     

Synthesis of composite solid electrolytes based on polyacrylic acid via radical polymerization initiated from silica surface

A procedure has been developed for the synthesis of silica-supported polymerization initiators, which includes chemisorption of (3-aminopropyl)triethoxysilane, hydrolysis of the alkoxy groups, and chemisorption of 4,4′-azobis(4-cyanopentanoic acid). It has been found that the reaction of 4,4′-azobis(4-cyanopentanoic acid) with immobilized amino groups in the presence of N,N′-dicyclohexylcarbodiimide involves only one functional group in the former. The effect of the solid support porosity on the composition of organosilica obtained by surface-initiated radical polymerization of acrylic acid has been studied. The best yield of grafted polyacrylic acid is obtained on aerosilogel with large mesopores in combinations with developed surface. The dependence of the impedance of polyacrylic acid-modified aerosilogel on the relative air humidity has been studied, and the possibility of using this material in humidity sensors has been shown.     

Synthesis of 1,3,6-triaryl-6-trifluoromethyl-5,6-dihydro-1,3,5-triazine-2,4(1H,3H)-diones by reaction of aryl trifluoromethyl ketone imines with aryl isocyanates

Russian Journal of Organic Chemistry -     

Study of chromium ion sorption on modified silica ordered materials

The sensitivity of chemical sensors depends on the number of receptors on the surface; hence, an important role is played by the accessible support surface. Films based on silica mesoporous mesophase materials feature the highest specific surface area for silica materials, and their walls can be modified by various functional groups. In this paper, we propose to use mesoporous mesophase films as supports of sensitive elements for Cr³⁺ ions.     

Reduction of 3,4-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole 2-oxide

Russian Journal of Organic Chemistry -