THE MEDIUM EFFECTS IN THE SULPHONATION OF POLYCYCLIC AROMATIC HYDROCARBONS

Abstract

Both the relative reactivities and the initial isomer distributions in the sulphonation of polycyclic hydrocarbons were found to be strongly dependent on the composition of reaction medium.     

Investigation of Condensed Media in Weak Fields by the Method of Nuclear Magnetic Resonance

Russian Physics Journal - A compact design of a rapid-response nuclear magnetic spectrometer for investigation of condensed media in weak fields is reported. As a result of investigation of...     

New Achievements in the Field of Intramolecular Phenolic Coupling Reactions,Using Hypervalent (III) Iodine Reagent: Synthesis of Galanthamine

Our investigations on the oxidative possibilities of the hypervalent iodine(III) reagent established that phenyliodine(III)bis(trifluoroacclate) (PIFA) can provide one-pot contiguous coupling-cyclization reaction giving a product with narwedine skeleton, when used in a phenolic coupling reaction of p'-bromonorbelladine derivatives. A suitably selected precursor gave up to 60% yield of the coupled product.     

Dielectric properties of liquid crystalline composites doped with nano-dimensional fragments of shungite carbon

A cholesteric liquid crystal (CLC) – cholesteryl tridecylate (X-20) was doped with nanoparticles of shungite carbon (Sh) to effectively improve some physicochemical properties of the CLC matrix for the further use in electronic devices. The influence of Sh (concentration of 0.005 and 0.02 wt. %) on phase transition temperatures of X-20 was studied. Addition of 0.005 wt. % of Sh shifts phase transition temperatures upward, while the concentration increase to 0.02 wt. % leads to the opposite effect. These data were taken into account during the study of dielectric properties in different phase states. The dielectric properties were studied in the frequency range from 20 Hz to 10 MHz. Only for the system X-20/Sh (0.02 wt. %), dispersion of the dielectric permittivity was observed. The dispersion was caused by the appearance of additional relaxation processes and it was substantially more extended than the classical Debye theory suggests. The results of the research show that the ‘CLC – Sh nanoparticles’ composites can be used as promising materials to increase the efficiency of radio electronics devices.     

Isotopically invariant dunham parameters and the potential function of the HCl molecule

The isotopically invariant Dunham parameters U _mj , Δ _mj ^H and Δ _mj ^Cl were determined by simultaneously fitting the line centers of vibration-rotation transitions of six isotopic HCl forms in the ground electronic state. Fitting included relations between U _mj values. The parameters of the isotopically invariant potential of HCl were determined using independent U _m0 and U _m1 values. The contributions to the vibrational terms of H³⁵Cl caused by violation of the Born-Oppenheimer approximation were calculated.     

Classification of topologies on finite sets using graphs

With the use of directed graphs, we study topologies on finite sets. On this basis, we propose a new classification of these topologies. Some properties of T ₀-topologies on finite sets are proved. In particular, we prove the existence, in T ₀-topologies, of open sets containing any number of elements that does not exceed the cardinality of the set itself. Translated from Ukrains'kyi Matematychnyi Zhurnal, Vol. 60, No. 7, pp. 992–996, July, 2008.