Химия

Sensor obtained by ion associate of vitamin B6 with tetraphenylborate ion and determined its electrochemical characteristics. Method biionnyh potentials determined selectivity coefficients of the electrode. The method of determination of the main substance in the product «Pyridoxine hydrochloride».

The ability of using cellulose diacetate (CDA) as matrix for luminescent determination of polycyclic aromatic hydrocarbons (PAH) in aqueous media was studied. PAH sorption was carried out on the example of pyrene from water solutions. Cellulose diacetate matrix was modified by anionic and cationic surfactants - sodium dodecylsulphate (SDS) and cetyltrimethylammonium bromide (CTAB). The comparative analysis of dependence of fluorescence intensity and polarity index of pyrene was carried out.

By differential scanning calorimetry (DSC) was first investigated experimentally determined complexes and phase characteristics of equilibrium points of the invariant three-phase triangles reciprocal systems of several Li,M || I,NO3 (M – Na, K, Rb). The compositions of eutectic (mol%) Li,Na || I,NO3 : (E1 ) NaNO3 – 42,5%, NaI – 5,0%, LiNO3 – 52,5% with a melting point of 178 °C. Li,K || I,NO3 (E2 ) LiNO3 – 44,0%, KI – 2,0%, KNO3 – 54,0% (mol) with a melting point of 117°.

The isothermal behavior of systems SDS – H2 O and SDS – H2 O – electrolytes has been investigated in the range 0–100 °C. The effect of the addition of sodium chloride, salicylic acid and sodium salicylate on the nature of phase transitions was shown. The viscosity of aqueous solutions of SDS (0–30 wt. %) was studied. The view about the nature of possible self-assembled structures in the systems was expressed.

The quaternary mutual system Li,K||F,MoO4 ,WO4 was partitioned into the simplexes and described the chemical interaction by conversion method and by method of ion balance. The prediction of the crystallizing phases conducted on the basis of the partition and of the equations for the reactions of conversion lines and for the method of ion balance.

An elemental composition and particle size distribution of the solid residue oil sludge are investigated, and a test samples series of a composite material is performed. The physico-chemical and operational properties of this material are investigated. Found that the characteris tics of the resulting material allow to use it in production of bituminous concrete for road construction.

In this paper is presented quantum-chemical research of the mechanism of reaction of an acylating butylmethylamine by propionyl chloride in the presence of lithium hydride. The estimate of two basic synthetic paths of an acylating butylmethylamine is made. Prereactionary complexes, transient states and reaction products are computed in program PRIRODA by a density functional theory (DFT) in approximation PBE and basis L1. Activation energies of reactions are computed. 

This work shows the possibility of synthesizing previously unknown 5-(4-bromophenyl)-3-((6-amino-2-mercaptopyrimidine)-4-amino)) methylidene-3H-furan-2-one containing a pharmacophore pyrimidine fragment by four-component one-pot reaction of malononitrile as the second methylene active component, thiourea, orthoester and 5-(4-bromophenyl)-3H-furan-2-one, which proceeds under mild conditions during thermal activation of the reaction mixture in isopropyl alcohol.

The structural and sorption properties of composite sorbents based on natural bentonite modified with carbon compounds have been investigated. Modification of the initial bentonite by low-temperature (650°C) pyrolysis of sucrose in the presence of metal salts of the iron subgroup leads to a significant increase in the specific surface area of composite sorbents (up to 275 m2/g), this is due to low-temperature catalytic graphitization of the carbon fraction formed during pyrolysis.

One of the widely used antibiotics of the penicillin series in medicine are amoxicillin and amoxiclav – the representatives of "protected" penicillins. To control the concentration of these antibiotics, HPLC, spectrophotometry, capillary electrophoresis are applicable, which are long-lasting, require expensive equipment, operators and are not applicable for the express determination of aminopenicillins in biological and medicinal aqueous.