The most suitable method for the ecology and economy of the country is to obtain calcium nitrate using raw materials.
Список использованной литературы:
1. Hojamuhammedowa B., Hajyyew M. D. Esasy organiki dal sintezin tehnologiyasy I bolum. - A§gabat, 2010.
2. Карякин Ю. В., Ангелов И.И. Чистые химические вещества. - Москва, 1974.
3. Беглов Б. М., Намазов Ш. С., Дадаходжаев А. Т., Юлдашев Ш. Х., Ибрагимов Г. И. Нитрат кальция. Его свойства, получение и применение в сельском хозяйстве. - Ташкент: "Мехнат", 2001.
© Charyyeva G. D., Atamyradov K. D., 2024
УДК 547
Esenova M.H.
Instructor of Oguz han Engineering and Technology University of Turkmenistan Ashgabat, Turkmenistan
ADSORPTION PROPERTIES OF METAL-ORGANIC FRAME WORK STRUCTURE OF MOF - 5
Annotation
It has been shown that the synthesized metal-organic compounds based on teraphthalic acid and ions have the structure of MOF - 5 and they have been studied synthesized MOF-5 sample obtained by scanning electron microscopy. It's clear that the crystals have a well-defined cubic structure.
Keywords
Metal-organic framework; microscopy, structure, acid, adsorption.
Metal-organic framework (MOF) materials, which are constructed from metal ions or metal ion clusters and bridging organic linkers, exhibit regular crystalline lattices with relatively well-defined pore structures and interesting properties.
MOF
Figure 1 - Structure preparation of MOF 5
MOFs exhibit unique physical and chemical properties, which include: wide possibilities for varying their chemical composition, flexibility of the metal-organic framework, the possibility of forming the so-called. "intertwined" (such as catenane structures) as well as extremely high porosity and low crystalline density.
The modular or block structure of MOF-5 contributes to the regulation of the spatial structure, as well as the pore geometry and functionality of these materials, through the rational selection of inorganic and organic building units, as well as the way they are connected. For example, depending on the coordination number of the inorganic center (metal ion) and the nature of the organic linker, pores ranging in size from ~0.5 to several nanometers can form in MOF-5 matrices [1].
Figure 2 - The structure of MOF-5 is presented in the form of ZnO4 tetrahedra connected phenylene dicarboxylate units
The purpose of this study is the synthesis and assessment of the physicochemical and adsorption properties of metal-organic compound MOF-5, synthesized on the basis of terephthalic acid and zinc.
Preparation of MOF-5 of a known structure for the creation of hybrid functional materials - adsorbents, carriers of heterogeneous catalysts containing metal nanoparticles, and membranes with a mixed matrix. Development of new methods and express methods for obtaining metal-organic frameworks, as well as a comprehensive study of the physicochemical properties of the resulting compounds.
The choice of synthesis strategy depends on the type of framework being formed. So, when preparing carboxylate metal-organic frameworks, the presence of a base, usually an amine, is necessary to deprotonate the organic acid (future organic linker) and initiate the reaction. In this case, it is important to exclude competitive coordination of the base and organic acid.
Methods for synthesizing MOF-5 have in three steps. The earliest of them is the so-called. "slow diffusion" method. A necessary condition for such a synthesis is the high solubility of the components of the reaction mixture. According to this technique, there is a slow diffusion of a volatile amine into a dilute solution of a metal salt and an organic acid at room temperature and atmospheric pressure. The disadvantage of this methods is that the synthesis takes too long time (1 - 2 weeks). In as a result, large crystals (several hundred micrometers) are formed, which are used mainly for structural studies [5].
DMF
H2BDC + Zn(NO3)2 • 6H2O Zn4O(BDC)3 Z^O(BDCb
3000C, 2,5 h, (DMF)y
C2H5OH,
Figure 3 - MOF-5 synthesis of metallic organic frame work compounds
Later, the hydro/solvothermal method, widely used for the preparation of zeolites, was used to synthesize MOF-5. This method made it possible to reduce the reaction of 2.5 hours . In this case, crystallization of MOF from dilute solutions in polar solvents (DMF, water, ethanol) is usually carried out in autoclave at moderate temperature (not higher tha5n 1100C) [3, 4]. Under solvothermal synthesis conditions, it is possible to overcome the limitations on the solubility of reagents [5].
References
1. J. L. C. Rowsell, O. M Yaghi, Metal-organic frameworks: a new class of porous materials // Micropor. Mesopor. Mater., 2004, 73, 3-14.
2. Yaghi O.M., Li G., Li H. // Nature. 1995. 378. Р. 703-706.
3. Yaghi O.M., Li H. // J. Am. Chem. Soc. 1995. 117. Р. 10401-10402.
4. Пат. РФ 2213055 (2000 г.). Способ получения модифицированного цеолита.
5. Isaeva V.I. "Гибридные материаллы на основе металл-органических каркасов (MOF) и исследование их каталических и физико - химических свойств" Москва, 2016.
© Esenova M.H., 2024