Pyrylium sulfonate based ionic liquids

Pyrylium salts represent a new group of ionic liquids (ILs) containing a positive charge on the oxygen atom. The novel ILs were obtained starting with 4-pyrones from petroleum feedstock and renewable resources and sulfonic acids. The use of carboxylic acids instead of salts resulted in the formation of cocrystals. The synthesized pyrylium ionic liquids were stable in air and in contact with water and common organic solvents. The permanganate indices which are characteristic for prepared sulfonates were also investigated. The pyrylium ionic liquids were useful as immobilizers and dissolving agents in hydrosilylation reactions.     

RF system for VEPP-5 damping ring

This paper presents the RF system of VEPP-5 damping ring created at BINP Novosibirsk. The RF system operates at 700 MHz and consists of a generator based on KU-393 klystron, a transmitting waveguide with wave-to-coax adapters, an accelerating cavity, and a control system. Cavity HOMs are damped with resistive loads to eliminate the beam instability. Parameter results of cold measurement tests and high-power level tests are presented.     

Reactions of azoles with tetrachloro-1,2-difluoroethane and 1,2-dichlorodifluoroethylene

Tetrachloro-1,2-difluoroethane reacted with pyrazole and imidazole sodium salts to give mixtures of the corresponding N-(1,2,2-trichloro-1,2-difluoroethyl) derivatives and (E)-1,2-difluoro-1,2-dihetarylethenes. (E)-1,2-Difluoro-1,2-di(3,5-dimethyl-1H-pyrazol-1yl)ethene was also obtained as a result of replacement of chlorine atoms in 1,2-dichloro-1,2-difluoroethene. Analogous reaction with more nucleophilic imidazole involved replacement of not only chlorine but also fluorine atoms in 1,2-dichloro-1,2-difluoroethene, yielding tetraimidazolyl-substituted ethylene.     

<Emphasis Type="Italic">N</Emphasis>-(2-chloro-1,2-difluorovinyl) derivatives of azoles

Reactions of N-(2,2-dichloro-1,1,2-trifluoroethyl)-substituted azoles with zinc, magnesium, butyllithium, and tris(diethylamino)phosphine were studied, and optimal conditions for the preparation of the corresponding N-(2-chloro-1,2-difluorovinyl) derivatives were found [tris(diethylamino)phosphine, chlorotrimethylsilane]. Some reactions of the obtained unsaturated fluorinated compounds with sulfur-centered nucleophiles were examined.     

Current Status and Planned Upgrades of the VEPP-5 Injection Complex

Physics of Particles and Nuclei Letters - The VEPP-5 injection complex, consisting of two linacs and a damping storage ring, delivers electron and positron beams to the VEPP-4M and VEPP-2000...     

Description of Simple Exceptional Sets in the Unit Ball

For z B ⁿ, the boundary of the unit ball in . If the exceptional set for f. In this note we give a tool for describing such sets. Moreover we prove that if Eis a G and F subset of the projective (n– 1)-dimensional space then there exists a holomorphic function fin the unit ball B ⁿso that E(f) = E.     

Stress Assessment in Artistic Materials Using a Micro-Scratching Technique

Experimental Techniques - The paper presents an experimental procedure based on micro-scratching to detect stresses in the ground layer of panel paintings. The method relies on the fact that...