I. V. Novikov

Volatility of some aromatic nitrosubstituted plasticizers for polymers

Nine derivatives of nitrophthalic acids and nitrophenols were synthesized as potential plasticizers for polymers and structurally characterized by 1H NMR and elemental analysis. The time dependences of the weight loss for the nitro derivatives synthesized and for commercial plasticizers (dibutyl phthalate and dioctyl phthalate) were obtained by gravimetric method at 100ºC, and their volatilities and dipole moments were calculated. The resultant nitroplasticizers are considerably less volatile than dibutyl phthalate. Low volatility is associated not so much with high molecular weight as with high polarity. The nitroplasticizers are well compatible with cellulose esters and exhibit low rates of migration from polymer films.

Mesomorphic and dielectric properties of the systems based on nematic cyanobiphenyls

Nematic cyanobiphenyls have been modified with small amount of polar additives. Phase transition temperatures as a function of composition of the prepared mixtures have been determined by polarization thermomicrscopy. The dielectric constant as a function of temperature has been determined via dielcometry measurements, and the dielectric anisotropy of the studied mixtures has been revealed. Broadening of the mesophase existence temperature range and enhancement of the dielectric anisotropy of the nematic biphenyls upon addition of polar dopants results from the supramolecular self-assembly via hydrogen bonding.

Homogeneous catalysis of n-propyl mercaptan oxidation with a cobalt tetraphenylporphyrin complex

A kinetic study of the oxidation of n-propyl mercaptan (PrSH) with chloridotetraphenylporphyrinatocobalt(III) in the absence of oxygen has been performed. The activation parameters of this reaction have been found to be close to those of the oxidation step of the Co(II) complex, and the structure of the transition state has been hypothesized. A stepwise mechanism of PrSH oxidation in the presence of Co complexes is proposed, comprising the sequential oxidation of PrSH with cobalt(III) tetraphenylporphyrinate and the oxidation of the resulting Co(II) complex with oxygen. The adequacy of the proposed scheme has been kinetically substantiated using the experimental data.

Optically active 4-(4-{4-[(2S)-(2-methylbutoxy)]benzoyloxy}-phenyldiazenyl)benzaldehyde

Abstract4-(4-{4-[(2S)-(2-methylbutoxy)]benzoyloxy}phenyldiazenyl)benzaldehyde was synthesized and its structure was identified.

Dielectric and orientation effects of ‘classical’ and supramolecular liquid crystals self-assembly

ABSTRACT Fragments of phase diagrams of binary systems containing 4-pentyloxy-4ʹ-cyanobiphenyl (5OCB) and 4-(ω-hydroxyalkyloxy)-4ʹ-cyanobiphenyl (HO3OCB, HO6OCB and HO9OCB) were obtained. The temperature range expansion of the nematic phase at mixing of the components was established. The dielectric and optical properties of binary mixtures were studied. A significant increase in the dielectric anisotropy was observed when the ‘classical’ liquid crystal (LC) was mixed with supramolecular HOnOCB. From the data on birefringence and the 1H NMR spectra, temperature dependences of the orientational order parameter of the ‘classical’ LC + supramolecular LC systems were obtained. There is a good agreement between S values obtained by independent methods. The invariability of the order parameter at mixing 5OCB with HO3OCB and HO9OCB and some growth in systems containing HO6OCB were observed. On the basis of quantum chemical calculations, the analysis of the most probable types of components association in the systems 5ОСВ + HOnOCB was carried out. From the analysis of Kirkwood correlation factors, the main role of competition between the two mechanisms of intermolecular interaction was revealed. ABSTRACT