Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya

6-11

Authors: Aliev И.А. , Sinegovskaya L.M. , Trofimov B.A.

The purpose of this research was to develop a selective rapid method for verifying the presence of palladium. For the first time, 2-(4-ethilthiophenyl) pyrrole has been used as a reagent for palladium determination. The reagent was obtained by the Trofimov reaction from 4-ethylthiophenylketoxime and acetylene at atmospheric pressure (Potassium Hydroxide/Dimethyl Sulfoxide, 96 °С, 5 h). It is established that Pd (II) and 2-(4-ethilthiophenyl) pyrrole form a complex compound of yellow colour in hydrochloric solutions (6 M of HCl, with a pH of up to 5). This compound absorbs in the visible region, λ = 415 nm. The properties of the palladium pyrrole complex were studied by an extraction-photometric method. The limits of Pd (II) concentrations (0,5-5,0 μg/ml), obeying the basic law of photometry, were revealed. The developed method for verifying the presence of Pd has been tested on complex solutions and the samples of industrial catalyst RC-404. It is shown that the new reagent provides a high selectivity of Pd (II) determination in the presence of Ag (I), Mn (II), Zn (II), Pb (II) and Ni (II), Al (III), Fe (III), Bi (III), Th (IV), Pt (IV), (VI), W (VI) and (VI), with the accuracy of analysis being ± 4%. In comparison with other analytical reagents, 2-(4-ethylthiophenyl) pyrrole is characterized by a high accuracy and good reproducibility of results, as well as by the selectivity and promptness of the analysis (4-5 min).

17-24

Authors: Dragunskii A.V.

Research into the kinetics of processes associated with the regeneration of spent chromium-containing solutions primarily aims to determine such basic parameters, as the order and rate constants of the reactions involved, their activation energies and transference numbers. All these parameters determine the efficiency of the regeneration process and its power consumption values. In addition, knowledge of these dependencies is essential for the selection of optimal operating modes of a device for regenerating spent chromium-containing solutions, as well as for the development of mathematical models and engineering calculation methods describing such processes. On the basis of experimental data, a functional relationship between changes in the values of electric current intensity and transference numbers has been established. The optical density of samples was measured using a photoelectric concentration colorimeter KFK-2-UHL 4.2. The voltage and current intensity values were controlled and regulated using a power supply unit Mastech HY3005-2. It is shown that an increase in the intensity of electric current leads to a decrease in the mobility of chromium ions. This occurs because the gas is absorbed by the solution, which prevents the passage of electric cur-rent. In addition, an increase in the current intensity results in the deposition of chromium on the electrode. Optimal dependencies between the key kinetic characteristics and parameters of the re-generation process are provided. Diagrams are presented for calculating optimal parameters of the process and corresponding power consumption values, which can be helpful in carrying out the re-generation of spent chromium-containing solutions with a high efficiency.

9-18

Authors: A.A. Chumakov, O.A. Kotelnikov, Yu.G. Slizhov

Fenton reaction systems are applied in organic synthesis for the selective oxidative functionalisation of hydrocarbons, organonitrogen and organosulfur compounds. For the Fe3+/ H2O2 complex, a mechanism is proposed for the oxidative activation of hydrogen peroxide, which involves the transfer of a proton resulting in the formation of oxywater Fe3 + -O-+OH2, which dissociates heterolytically, liberating water and generating a complex of iron (III) -1D-oxene [Fe3+O0(1D)]3+, where the oxygen atom is in the singlet quantum state (2p [↑ ↓ ] [↑ ↓] [_]). This intermediate is intended to be a selective oxidant of organic compounds. The aim of the work is to study the selectivity of oxidation of pyridoxine with hydrogen peroxide in an aqueous solution in the presence of iron (III) ions, bound to complexes by organic molecules. The structure of the oxidation product was studied using proton and carbon nuclear magnetic resonance (NMR) methods. Based on the results of NMR spectroscopy, the primary conversion pathway in the system is based on oxidation of the primary alcohol group at the 4carbon atom of the pyridine nucleus to the carboxyl group, which acylates the hydroxyl group at the 3-carbon atom of the neighbouring molecule to form an intermolecular ester bond. As a result, a cyclic oligomer is formed, comprising two or three monomeric units.

35-41

Authors: Yu.N. Pozhidaev*, O.V. Lebedeva*, G. Burmaa

An extensive number of organic sorbents can be used for extraction of precious metals from solutions, among which organosilicon sorbents deserve a particular attention. The sorption activity of organosilicon sorbents is determined by the nature of the functional group and its position in the polymer chain. In this study, the effect of the nature and position of the functional substituent on the sorption activity of polyalkylsilsesquioxanes with respect to Ag (I) and Au (III) ions is analyzed for polymer homologues and polymer analogs with sulfhydril, sulphonic, thioalkylamine, guanidine, biguanidine, malonodiamide and phthalamide groups. It is shown that the sorption activity of the com-pounds under study increases during a transition from polyalkylsilsesquioxanes, containing chemically active groups in the  -position, to their polymer homologues, containing these groups in the  - и  -position. The sorption activity of complexing polymers is determined by the stability of the chelate compounds formed, the number of donor-active atoms in the functional groups and their spatial position facilitating the formation of complexes

51-58

Authors: N.D. Zambulaeva, S.D. Zhamsaranova

This paper is aimed at investigating the antimicrobial and antioxidant properties of dried cranberry and cowberry extracts, as well as assessing the possibility for cranberry extract to be used in the production of biscuits having antioxidant attributes. By-products from berry processing contain biologically active substances, such as phenolic compounds and benzoic acid, the extraction and concentration of which allowed dried berry extracts to be obtained for further use as possible functional ingredients. The radical binding and Fe2+chelating ability of the extracts and their antimicrobial action towards Escherichia coli, Staphylococcus aureus, Bacillus cereus, Salmonella typhimurium, Listeria monocytogenes are determined. The possibility for dried extracts obtained from berry processing by-products to be used in the production of sugar-containing biscuits of increased biological value is investigated. The level of antioxidants in the experimental sample is shown to exceed that of the control sample by 5.2 times, proving the extract to be an effective ingredient in the production of confectionery and other food products.

67-73

Authors: T.V. Katsurba, S.N. Evstaf'ev, V.K. Frantenko, A.I. Demina

There is little scientific data on the use of sodium selenite, a mineral form of selenium, as an intensifier of malting. Therefore, this work is aimed at investigating the possibility of using sodium selenite in accelerating the malting process. To this end, barley of the Acha variety was soaked in an aqueous sodium selenite solution. The malt was obtained using the air-irrigation soaking method, with the barley being germinated in a laboratorybased malting plant. During the experiment, the degree of soaking and the temperature of the grain layer were varied. Under various conditions of barley soaking and germination, the maximum amylolytic activity of the malt was observed on the 4th day of germination. The addition of sodium selenite led to the accumulation of amylases on the 3rd day of germination. Based on the experimental data and mathematical modelling, the maximum amylolytic activity of the malt, when a sodium selenite aqueous solution with a concentration of 0.033 mg / l was used, was established. The amylolytic activity of the malt obtained by soaking barley grain with sodium selenite was shown to be 1.5 times higher than that in the reference sample. Thus, our studies have shown that sodium selenite can be used as an intensifier of the malting process

82-91

Authors: N.M. Musta Ogly*, N.Yu. Sharova*,**, A.R. Yushkauskaite**

This research sets out to study the activity of the phytase enzyme synthesized by the Aspergillus niger L-4 fungus strain in sucrose-mineral medium and to determine optimal conditions for culturing this strain, under which the greatest amount of the phytase enzyme can be synthesized. The possibility of obtaining the phytase enzyme as an additional target product of microbiological synthesis is investigated. The activity of the phytase synthesized by the Aspergillus niger L-4 micromycete is studied by the colorimetric method. This method is based on the determination of inorganic phosphates (PO4) that form as a result of the phytase enzyme action on the sodium phytate substrate (sodium salt of phytic acid): under standard conditions the phosphates react with the vanadium-molybdenum reagent to yield a phosphor vanadium molybdenum complex of yellow colour. As a result of the fermentation of the Aspergillus niger L-4 strain into citric acid in a sucrose-mineral medium, the maximum activity of phytase in native solution constituted 68.75 units/cm3 for the inoculated mycelium aged 24 and 48 hours, at different volumes of inoculated mycelium (15 and 20%, respectively) and a temperature of 29 ºC.

99-105

Authors: Y.A. Zykova, N.M. Samokhvalov, V.V. Vinogradov

This aim of this research was to study the mechanism and efficiency of the regeneration of filtering walls by means of reverse jet blasting with a rotating nozzle during dusty gas treatment by a slotted filter. Within a series of experiments, the rotational speed of the blowing nozzle and its distance to the filtering wall, the number of wire layers and the gaps between them were varied. Air consumption for filtration and purging was measured along with the hydraulic resistance of a clean filtering wall, a wall with dust sedimentation and one following regeneration. The balance of the forces acting on the dust sediment during regeneration and the conditions for the separation of the sediment from the filtering wall were analysed, allowing the minimum velocity of the blowing jet to be mathematically defined. A dependency relation is proposed for calculating the effective working speed of the jet, which ensures efficient regeneration and minimum purging costs. The efficiency of regeneration is found to be exponentially related to the residual creep resistance index determined by the conditions of filtration and regeneration. A dependency relation is derived to calculate the regeneration coefficient, which can be recommended for determining the total hydraulic resistance of the slotted filter, taking into account the resistance of the clean filtering wall, the resistance of the dust sediment and the residual resistance of the filtering wall after regeneration

115-121

Authors: N.A. Belokonova, E.Yu. Ermishina, N.A. Naronova, T.V. Borodulina

This paper is aimed at assessing the possibility of using passive transport processes through semipermeable membranes of cellulose acetate as a criterion for the evaluation of the properties of adapted milk formulas and breast milk. The content of potassium and sodium ions and that of calcium and magnesium in the calcined milk mixtures prepared for the analysis were determined by the potentiometric and titrimetric methods, respectively. The data obtained was used to estimate the rate of diffusion from reconstituted milk mixtures. The permeability coefficients of potassium, sodium, magnesium and calcium ions were calculated for reconstituted milk mixtures and an experimental solution that simulated the milk mixtures used in the study in terms of their ionic composition. The diffusion of ions in vitro, which was evaluated using the permeability coefficient, is demonstrated to be identical to the processes of absorption through the gastrointestinal canal wall. The results of the study demonstrate that, in contrast with breast milk, no caseinate cell phosphate complex forms during the reconstitution of adapted milk mixture. This is evidenced by a higher diffusion rate of calcium and magnesium ions from reconstituted adapted milk mixtures than that from breast milk. The calcium and magnesium ions are absorbed less easily from infant formulas than from breast milk