Topicality and demand of the theme of dissertation. One of the actual problems of modern physical chemistry and macromolecular chemistry is the study on the development of the fundamentals of synthesis of functional polymers with ion-exchange and complexing properties.
Anion exchange and complexing compounds based fibrous materials have a high specific surface area, which provides a high possibility of sorption and desorption processes. They arc especially effective in removing toxic substances, even at very low content of the latter from the air and water pollution. Of particular interest is the acrylic fiber "Nitron", which is produced by JSC "Navoiazot" (Uzbekistan).
In the Academy of Sciences of the Republic of Uzbekistan, Tashkent Institute of Textile and Light Industry conducted research on the development of fibrous ion exchange materials based on acrylic fiber "Nitron" but they have not been brought to its logical end. In addition, when these studies neglected the study of the physicochemical aspects of the preparation of these materials.
In developing the fundamentals of ion exchange materials obtaining a lot of attention paid to the study of physical and chemical aspects of the synthesis and properties of these high-molecular compounds. These studies due to the fact that they allow you to adjust the processes of synthesis and, therefore, necessary to obtain polymers with required composition and with complex specific properties.
As noted above, to date, no attention was paid to the study of the physicochemical foundations of anion exchangers and polycomplcxons, due to applied research conducted to date in this field of research. In this regard, the study of physical and chemical principles of bases of creation, and the properties of anion exchangers and polycomplcxons based on acrylic fiber "Nitron" arc actual both from a theoretical and practical point of view.
Demand perform of the dissertation is characterized by the fact that modern worldwide technology for extraction of non-ferrous and precious metals can not be realized without the use of ion-exchange materials. These techniques use mostly granular sorbents, while fibrous sorbents comprise just 2-3 % of the ion exchange materials used . Using technology employing ion exchange material from algae and natural brine deposits of oil and gas recovered to 90% of iodine and bromine, lodinc-containing sorbents arc used for disinfection of drinking water from microorganisms and extraction of mercury from wastewater and gas emissions. They can be used for concentrating the processing solutions and biologically active substances in the preparation of catalyst systems nanoparticles metals. It should also be noted that Uzbekistan hitherto not been established as industrial manufacture granular and fibrous sorbents, although such polymers arc widely used in industry.
The purpose of this study is to identify the physico- chemical characteristics of the formation and properties of anion exchangers polycomplcxons based on acrylic fiber " Nitron ".
Scientific novelty of disscrtational research consists in the following:
in the first time studied the kinetics of the interaction of acrylic fiber "Nitron" with nitrogen-containing bases in aqueous and organic media;
shown that due to the high surface area fibers arc modifiable , the reaction rate depends on the concentration of the nitrile groups of the polymer being in the solid surface;
proved previously identified mechanism of the catalytic action of small amounts of hydroxylaminc on the process of modifying of fiber " Nitron " with nitrogen-containing bases;
in the first lime developed a method for producing anion exchangers branched structure by sequential treatment of acrylic fiber " Nitron " with cthylcncdiaminc and dichlorocthanc;
found that the interaction of PAN - fibers with hcxamcthylcnc- and ethylene diamines formed anion exchange fibrous materials having in its composition as a weakly basic and strongly basic functional groups ;
in the first time obtained new polycomplcxons with ampholytic properties by reacting maleic anhydride with amine -modified polyacrylonitrile fiber " Nitron " or by hydrolysis of residual of the nitrile groups modified with diamines of acrylic fiber "Nitron";
established values of the thermodynamic equilibrium constants of adsorption of ions Cr (VI), Си (II), halogens, Arsenazo (III) by synthesized anion exchangers and polycomplcxons and alteration in thermodynamic functions of the process testify to high sorption capacity of these ion-exchange materials with respect to the sorption ions;
Conclusion
1. Values degree reaction of the nitrile group and a nitrogenous base, the activation energy of the process shows that the process of modifying fiber " Nitron " nitrogen-containing bases subject to the usual regularities observed in homogeneous reactions. This effect is due to a high fiber surface area to be modified, allowing the reactants to facilitate access to the nitrile groups of the polymer. (Physical chemistry, High molecular compounds).
2. Kinetic studies of the reaction of acrylic fiber " Nitron " with diamine (hexamethylene and ethylenediamine) showed that the change of physical and chemical parameters of the modification process can be controlled sorption properties, chemical resistance and the strength of the anion exchangers due to network structure of the polymer. It has been established that this modification "Nitron" produces strongly basic anion character especially in organic media. Strongly basic anion exchangers possibility of obtaining a high sorption capacity with graft polycthylcnpolyaminc chain reactions revealed in fiber modification "Nitron " ethylenediamine in the presence of dichloroethane. (High molecular compounds, Physical chemistry ).
3. IR - spectroscopic and analytical determination of the formation of intermediate amidoxime groups in the polymer chains and free hydroxylaminc after substitution reaction proved previously proposed mechanism of the catalytic action of hydroxylaminc on the process of chemical modification of acrylic fiber " Nitron " nitrogen-containing bases . ( Physical Chemistry).
4. Developed conditions of synthesis polycomplcxons reacting maleic anhydride with modified by hcxamcthylcncdiaminc acrylic fiber "Nitron" and with of hydrolysis of residual nitrile groups modified by hcxamcthylcnc- and cthylcncdiamin of acrylic fibers . (High molecular compounds, Physical Chemistry).
5. Alkalinity obtained anion exchange resins depends on the nature of their functional groups. Strongly basic anion exchangers have in their composition cyclic amidine groups and they arc formed by the reaction of polyacrylonitrile fiber with a diamine. The specific surface area obtained fibrous sorbents exceeds by two orders of known surface area granular ion exchange resins, and their crosslinking rate is up to 100 nodes per macromolecule polymer. ( Physical Chemistry )
6. Kinetics and thermodynamics of the sorption of various inorganic and organic ions obtained polycomplcxons sorbents showed that ions of Cr (VI), Arsenazo (111) can be sorbed strongly basic anion exchangers only, and the process of sorption of copper (II) with polycomplcxons occurs not only due to the ion exchange, but also due to chelation. ( Physical Chemistry ).
7. Developed the conditions obtaining bromide complexes of polymers and kinetics, thermodynamics of the sorption halogen anion in synthesized materials was studied. It is shown that the lower the stability of the ion [Bn]’ for ion [J3]'than the ability to form such molecular chlorine ions leads to the fact that almost no molecular chlorine is adsorption, and molecular bromine is absorbed to a lesser extent than the molecular iodine. (Physical Chemistry ).
8. Combined developed iodinated anion exchange materials based on acrylic fiber " Nitron " and chitosan. Insertion of the iodinc-containing chitosan materials, leads to an increase of absorbent capacity. Combined antibacterial dressings have a pronounced anti-inflammatory and antibacterial effect, arc effective for the treatment of necrotic soft tissue diseases. (High molecular compounds, Physical Chemistry).
In this article, the problems of determining the optimal tax burden in the economy are scientifically and theoretically researched, in which issues such as the problems of determining the optimal tax burden in the national economy, the distribution of the tax burden in the economy, indicators that are important to consider when calculating the optimal tax burden are considered. Also, directions for determining the tax burden of enterprises were studied
ЖССТ маьлумотларига кўра болалар хирургии патологиялари ичида иккинчи ўринда сийдик айирув системаси касалликлари туради. Охирги ўн йилликда касалликнинг учраш частатаси 2,5-3 баробарга ортган ва хар 1000 та болада 20,6 дан 106,0 гаччани ташкил килади. Касалликнинг ортиб бориши хозирги кундаги долзарб муомолардан биридир. Болаларда сийдик тош касаллигининг эрта диогностикаси ва оптимал даволаш тактикасини танлаш.
The article theoretically investigates the value of the tax burden in the economy, the problems of its determination, the different views of domestic and foreign scientists on determining the optimal level of the tax burden in the economy, formulates scientific conclusions and recommendations.
The article provides a theoretical and practical study of the content of the tax burden, the problems of its determination in the economy, the views of domestic and foreign scientists on determining the optimal level of the tax burden, and also formulates scientific conclusions and recommendations.
The article theoretically investigates the value of the tax burden in the economy, the problems of its determination, the different views of domestic and foreign scientists on determining the optimal level of the tax burden in the economy, formulates scientific conclusions and recommendations.
Topicality and demand of the subject of dissertation. Development of science and intensification of all branches of national economy and also introduction of new technogenic processes of production have resulted in antropogenic influence of industrial activity of man on the environment and ecological equilibrium According to the data of regional evaluation of stable toxical compounds in the countries of the European Counsel the highest concentrations of Pb, Cd and Hg in the environment have been noted in the Ukraine (Pb-31,02; Cd-54, Hg-36 ton/year).Release of heavy metals to the environment for Russia equaled Pb-50%; Cd-66%; Hg-37% and in some others countries: Pb-10%,Cd-21%,Hg-58%,.Short analysis of the situation interms of these tree toxical metals has shown the level of antropogenic throwings of heavy toxical metals(HTM).The biggest part of HTM finding with throwings released to the atmosphere thrown out on soil and in waters of the country being the-surce the release and then they accumulate in neighbouring countries .
At presente time in the Republic of Uzbekistan the level of manufacture is rapidly growing and this results in the increase of the concervation of HTM compared with global scale of some natural processes. The most dangerous for the health of population are the non-essencial elements (Hg, Cd, Pb, As) . For this reason the monitoring of pollutions of objects of environment especialy HTM has acquired special importance and actuality. Qualitative and quantitative determination of ions of HTM has acquired important and necessary demands and has pulled out before analysts and ecologists the task of elaboration of express sensitive and selective methods of determination of microquantities of these elements which are dangerous toxicants, cancerogens and mutagens.
In this regard in the process protection of objects of the environment it is important and necessary to determinetion precise concentrations of HTM by different physical, chemical and physico-chemicals methods. For the practical realization of this problem at chemical analysis it is necessary to improve perfection existing methods analysis and elaborationof new modern methods ecotoxicants monitoring (espessially HTM). In the aspect of realization of theoretical prerequisites and practical confirmation of analytical determination of ecotoxicants concentrations it is necessary to elaborate some new hybrid methods with immobilization of different complexe-forming reagents on polymeric bearers and matrixes differing by high meteological and operation parameters.
Existing actual problems can be solved by introducing to the analytical practices of the methods of HTM determination of some new selective and specific organic reagents.The most perspective way of their solution is the purposeful synthesis and immobilization of new organic reagents with some definite analytical characteristics with following forecast of their properties with the aim of the optimal solving of the given tasks.
Elaboration of methods and approaches of prognosis as method of further development of sorbtion-spectroscopical method of analysis is an actual problem .In this range of theoretical and applied analytical chemistry there are considerable achivments bonding with investigations of home and forcing investigators ,but row of questions of problematical character has demanded of deep investigation and knowledges of new approaches and methods of their decision.
It is known that theory of action of OR is characterized as “system of ideas” allow ing to construct of some analytical system to find optimal by nature reagent and medium in which analytical reaction will carried out .In decision of some taskes of development of theory of OR action the fallowing stages neussarg to take into acconnl:”esplantion of observe processes and phenoments:prediction and direction works by synthesis of reagents with given properties .’’Thus the elaborated methodology and predication of properties of immobilized analytical reagents can be consider as definite seintific contribution in development of theory of action of IMOR for their using in analytical chemistry and ecology.
Purpose of research is elaboration of express, high-sensitive sorbtion-spectroscopical methods and test-systems of HTM determination with using of IMOR. Elaboration on the base of these methods some general approach to prognosis of properties and construction of specifical analytical grouos in organic reagents immobilized on different types of bearers synthesis of new organic reagents with given up properties on the base of our theretical prognosisesand introduction of them in practice of analysis of different analytical and ecological laboratories.
To achieve this goal the following tasks of research is solved: -optimization of immobilization conditions of organic reagents with preservation of their analytical properties; determination of mechanism of coloured reactious of complex-formation of immobilized organic reagents with ions of HTM;
-determination of connection between structure of OR and their analytical characteristics; prognosis of some perspective ways of their modification and directed synthesis of new specifical reagents on the base of nitronaphtols;
-analytical groups (EAG): (6-methyl-pyridil-2-azo-aminophenol; l-(5-methyl -2-pyridilfzo )-5-diethglaminophenol ;l-(4-antipyridilazo) -2-napthol sulphoacid; 1-(2-pyridilazo)-2-oxynaphtalin-6-sulphoacid sodlium; 3-hydroxy-4-nitrozo-2-naphtoic acid;2-hydroxiy -3-nitrozo naphtaldehyde and others);
-determination of influence of different factors and parameters on value of the analytical signal ;wing of elaborated methods in analysis of different by nature model binary ,triple and more complex mixtabiological objects industrial materials
-comparison of obtained results with results obtained by existing methods of determination of the investisated metals in solution.
Scientific novelty of disscrtational research consists in the following:
-Immobilization of different by nature reagents for prognosis and prediction of optimal construction of some OR based on quantum-chemical value of changing of analytical characteristics in dependence on structure of the functional and analytical-active groups has been theoretically based and practically has been realized;
-Chemico-analytical properties of OR immobilized on bearers on the base of polyacrylonitrile (PAN) and polypropylene (PP) for apriory prediction of structure of different OR and elaboration on their base an optical chemical sensors on the base PAN and PP-matrixes having some necessary analytical parameters;
Conclusion
1. Litrature date about using fiber sorbents and ion-exchanging on their base for determination of HTM cations at analysis objects of environment have been summarized. Advantages of using of fiber sorbents in comparison with their using as granule and powder have been shown. Necessarily of search of new immobilized reagents for determination metals in different objects was ground.
2. New scientific trend in analytical chemistry based on the sorbtion-spectroscopical determination of HTM in different objects of enviroment with using immobilized on fiber material organical reagents of different nature with aim of improvment of metrological parameters, exploitational and analytical parameters was developed.
3. Pysico-chemical and analytical properties of immobilized reagents on the base of reagents Arsenaza and threephenylmethan row and also synthesized on the department of organical chemistry NUUz sorbited on the fiber “Nitron” were systematically investigated. Optimal conditions of immobilization of new reagents on some polymeric bearers with preservation of theirspecifical analytical properties were determined.
4. 1R- spectroskopical investigation of immobilized reagents of fiber sorbents and their complexes with cations of HTM was carriedout. It was proved that in complex-formation of HTM ions with immobilized reagents the same functional analytical groups participated as in case of native solutions.
5. Results of investigations of interaction of reagents group Arsenazo and theephenylmethanic raw and also reagents synthesized on the derailment of inorganical and analytical chemistry of chemical faculty ofNUUz immobilized on marix on the base of PAN and PP-fibers with ions of HTM have shown that their immobilization was carried out owing to ionic changing and also formation of strong intermolecular hydrogenous bonds with bearers.
6. Using of calculating quant- chemical methods such as EMN, MNDO, RMZ and AM-1 has allowed in apriori to predict the structures of different rengents having some necessary analytical parameters (sensibility, contrastion of reactions and conditions of their carring out).
7. On the base on comparison optimal conditions of immobilization, sorbtion, degree of extraction of metals ions, coefficients of distribution, sorbtion capasity of fiber sorbents, data about sensibility of the analytical action occording to ions Cd, Hg, Cu and Fe in presence of accompanying elements, possibilities of quantitative desorption by small volumes of mineral acids and accessibility of initialcompounds it is shown an perspective of practical using of synthesized reagents and fiber sorbents. Immobilized reagents quantitativly have extracted ions of metals during 20-30 min at temperature 20-25°C in pH diapazone 3-7 (R=90-99%).
8. Coplex of methods of solidphase - spectroshopical and visually-testing determination of HTM in natural objects and samples of sewage and also new effective method of sorbtion - spectroskopical determination of Co,Cu, Cu, Ni, Fe and Hg in drinking and natural waters with using of immobilized organical reagent has been elaborated . This sorbtion - spectroskopical method has allowed to determine abovementioned metals in drinking and natural waters on the level n x 10-6 - n x 10'3 % and also to decrease the limitof their determination . Rightness of elaborated methods was proved by method “introduced - determined” at analysis of some real abjects and also by comparison with data obtained by atom -absorbtion method.
9. Elaborated methods were aprobated at analysis of real objects and were introduced in practics of laboratories by investigation of surface waters NYSMY; SES (sanepidemic station) of Tashkent region and Bekabad; department of radiopreparates of INP (Institute of nucleur physies) and others. Some obtained experimental data have been introduced in educational process at reading of lectures , carring out seminars and labaratory works with bachelors and masters by courses : “Analysis of environment objects”; “Optical methods of analysis “ ; “Physical methods of analysis “ ; “ Metrology statistics and computer in analytical chemistry” on the departments ofNUUz ; SamSU; Term.SV Tash.Pharm.1.
The article provides a theoretical and practical study of the content of the tax burden and the tax burden on enterprises, the problems of optimizing the tax burden on enterprises, the views of local and foreign scientists on determining the optimal level of tax burden on enterprises. Keywords: tax burden, optimal tax burden, tax rates, tax burden on enterprises, tax relations.
The article analyzes the essence, definition, theory and paradigms of cultural diplomacy, international relations, "soft power", theoretical and conceptual foundations of the history of diplomacy, features of models of cultural diplomacy of leading foreign countries and its implementation in Uzbekistan. On this basis, methodological approaches to the study of the history of cultural diplomacy are discussed.
Мақолада охирги йилларда Ўзбекистонда чорвачиликка доир қабул қилинган норматив – ҳуқуқий асослар таҳлил қилиниб, фермер, деҳқон хўжаликлари ҳамда томарқа ер эгаларида ердан фойдаланиш ҳолати ва чорва маҳсулотлари етиштиришнинг кўрсаткичлари ўрганилган, ерлардан самарали ташкил этиш асосида чорвачилик тармоғини ривожлантириш бўйича илмий ва амалий таклифлар беришга ҳаракат қилинган.
The article analyzes the concept of prosecutorial supervision over the execution of legislation in the field of ecology and environmental protection considering its special features and objectives.
This article is devoted to the scientific study of some issues of the national - historical development of social protection of military personnel in Uzbekistan. In this regard, specific historical facts and theoretical foundations of the reforms carried out today in this area are given in more detail
Breech presentations remain as an urgent problem during delivery and occur with a frequency of 3 – 5 % of all births. Up today according to statistics the rate of caesarean delivery in BP accounts for 40 - 82 % and this has led to an increase in the number of women with prior cesarean delivery with corresponding complications. In recent literature there are reports about alternative methods of delivery in breech presentations. This article deals with the results of comparative evaluation of different methods of delivery in breech presentations.
Ўзбекистонда тегишли институционал асослар ва етарли даражада ишлайдиган тартибга солиш тизимига эга кўчмас мулк бозорини яратиш мамлакатдаги ишбилармонлик муҳити ва иқтисодиётдаги инвестиция фаоллигига бевосита таъсир кўрсатадиган энг муҳим вазифалардан биридир.