Method of obtaining mesoporous nanosized cerium dioxide powder (versions). RU patent 2506228.

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry, to production of nanosized powders of metal oxides for fine-grained ceramics of broad spectrum. Method of obtaining cerium dioxide powder includes stages: obtaining water 0.05M solution of cerium nitrate or cerium acetate, using Ce(NO₃)₃·6H₂O or Ce(CH₃COO)₃·H₂O, obtaining alcohol solution of stabiliser of sol of organic N-containing compound: N,N-dimethyloctylamine, tetraethylammonium hydroxide or monoethanolamine with concentration 0.45-3.30M, 0.37M and 0.016M, obtaining sol in water-organic system by combination of composed solutions, evaporation of water-organic system, formation of gel and thermal processing of gel in the interval of temperatures 95-500°C by step-by-step schedule, with application as sol stabilser of one of the following low-molecular organic N-containing compounds (N): N,N-dimethyloctylamine, tetraethylammonium hydroxide or monoethanolamine in form of alcohol solution with molar ratio N/metal, equal 1-20.

EFFECT: invention ensures technologically easily realised, economically efficient and non-toxic obtaining mesoporous nanopowders of cerium dioxide.

8 cl, 16 dwg, 1 tbl, 17 ex

The present invention relates to chemical industry, production of nanomaterials, to the technological processes of production of ultrafine powders of metal oxides, in particular to obtain nano-crystalline cerium dioxide, which is an intermediate for obtaining fine-grained ceramics broad spectrum assignment, nanostructured and mesoporous catalysts, composition and photosensitive materials, solid oxide fuel cells and other

Modern technology of fine-grained ceramic materials has specific requirements for physical-chemical properties of the original intermediates, ultra-fine powders of metal oxides. They must have certain textural and morphological characteristics: the phase composition and phase purity, the presence or absence of defects in the crystal lattice, the degree of stereometrical, dispersion, distribution, crystallite size, specific surface area, porosity characteristic.

The hallmark of fine-grained ceramics is the grain size is not more than 5 (according to some sources - 3) microns and a narrow size distribution. To obtain materials with such characteristics is necessary to create the appropriate intermediates, which include ultrafine or nano) powders of metal oxides. The size of the crystallites in them should not exceed 100 nm. This allows for the compaction and sintering of ceramic materials to obtain a grain size of 0.5 to 5.0 microns with a narrow distribution in size. The use of ultra-fine powders for ceramic materials allows to obtain more uniform distribution of components in the volume of the mixture for compaction. This is especially important in multi-component mixtures, where the content of individual oxides may be only a few percent or even fraction of a percent.

Is a recognized fact that traditional methods of obtaining powders associated with the shredding large pieces of the array, it is almost impossible to achieve the required characteristics of the original powders-intermediates for fine-grained ceramics. To obtain ultra-fine powders of metal oxides of the most acceptable methods are the so-called wet chemistry wet chemistry), where the main reaction medium used solutions and colloids. This precipitation, hydrothermal, microemulsion and Sol-gel methods.

The most cheap and simple in organization deposition method rarely allows to achieve the desired dispersion. Hydrothermal and microemulsion methods road and portable in hard industrial conditions. Practice has shown that the economic is Kim indications for technological realization is most appropriate Sol-gel method. For its realization it is possible to use a simple domestic equipment.

The Sol-gel method refers to techniques of "wet" chemistry and implemented in a "soft" conditions: at low temperatures and atmospheric pressure. The proposed method is based on a modified Sol-gel method allows to control the growth of crystallites at the molecular level by the selection of the qualitative and quantitative composition of the reaction mixture: the concentration of each of the source metal-containing reagents, molar relationships co-solvents, complexing agents and stabilizer Zola to metals.

Nano-crystalline ceria is a highly sought-after intermediate for production of a wide range of ceramic and quasiballistic materials for optical devices [Sujana M.G., Chattopadyay K.K., Anand S. Appl. Surf. Sci 254 (2008) 7405-7409], solid oxide fuel cells [Steele B.C.H. // Solid State lonics 129 (2000) 95-110], sensors oxygen [N. Izu, W. Shin, I. Matsubara, N. Murayama // Actual Sensors. B: Chem. 113 (2006) 207-213], semiconductors [Panhans M.A., R.N. Blumenthal // Solid State lonics 60 (1993) 279-298], electrochromic devices [Baundry P., A.C.M. Rodrigues, M.A. Aegerter, Bulhoes L.O. // J. Non-Cryst. Solids 121 (1990) 319-322], a wide range of materials for small-size electronic devices [Feng X., Sayle D.C., Z.L. Wang et al. // Science. 312 (2006) 1504-1508], nanostructured catalysts for Neftekhim and and environmental catalysis [G. Kirn // Ind. Eng. Chem. Prod. Res. Dev. 21 (1982) 267-274], membranes as catalytic and mixed conductivity [Fu Y.-P. // Ceram. Int. 35 (2009) 653-659], and it is known that the biocompatible form SEO₂are an important component of ceramic materials for implants [.V.Dudnik, A.V.Shevchenko, A.K.Ruban, V.P.Red'ko, L.M.Lopato; Microstructural design of ZrO₂-Y₂O₃-SEO₂-Al₂O₃materials; powder metallurgy and metal ceramics, vol. 49, Nos. 9-10, 2011 // W.Rieger, S.Leyen, S.Kobel, W.Weber; The use ofbioceramics in dental and medical applications; Digital dental news, 3, 6-13, 2009].

High demand for cerium dioxide due to the unique electronic properties of its lattice, high mobility in it of oxygen ions. In nano-crystalline cerium dioxide) have been observed size effect caused by the increase of lattice parameters with decreasing crystallite to sizes less than 10 nm. The result of the ongoing changes in the lattice formed by oxygen vacancies, and parts of cerium ions the oxidation number is reduced to +3. Nano-crystalline SEO₂get different methods: deposition [Abi-aad E., R. Bechara, J. Grimblot, Aboukais A. // Chem. Mater. 5 (1993) 793-797], solvothermal method [Hosokawa, S., Shimamura, K., Inoue M. // Mater. Res. Bull. 46 (2011) 1928-1932], microemulsion [Roderick E., C. Schrage, A. Grigas, Geiger D., Kaskel S. // J. Solid State Chem. 181 (2008) 1614-1620], when heated by microwave radiation [Ivanov VK, Polezhaeva O.S, Gil UP., Kopitsa G.P., Tretyakov WD // DAN, 2009, CH, No. 5, 632-634], ultrasound [D. Zhang, H. Fu, Shi L, Pan C., Li Q., Chu Y., Yu W. // Inorg. Chem. 46 (2007) 2446-2451], hydrothermal [Xu J., Li G., Li L. // Mater. Res. Bull. 43 (2008) 990-995].

Known attempts to obtain nano-crystalline powders of metal oxides, including ceria, methods of "wet" chemistry.

US Pat 8,029,754. The powder of cerium oxide and method thereof, 2011

Nho Jun-seok, Kim Jang-yul, Oh Myoung-hwan, Kim Jong-pil Cho Seung-beom hydrothermal synthesis were obtained fine powders SEO₂with the size of the spherical particles 10-500 nm. As the initial cerium-containing reagents have been used carbonate, chloride, sulfate and hydroxide of cerium. As the fluxes used the chlorides of sodium or potassium (or fluoride), the share of which in the reaction mixture was 0.5-10.0 wt.%. As dispersing agents used non-ionic polymer additives with a molecular weight of up to 4000: polyvinyl alcohol, ethylene glycol, glycerin, polyethylene glycol, polypropyleneglycol, polyvinylpyrrolidone, polyacrylate, ammonium polyacrylate, polyacrylat. The duration of the synthesis was achieved 12 hours Heat treatment was performed in the temperature range 70-1200°C in two stages. First, the obtained product was dried at a temperature of 70-200°C., and then subjected to calcination at 600-1200°C for 2-3 hours Feature is used the e highly diluted solutions of the starting reagents.

The disadvantages of this method include large volumes of liquid required to obtain powders of cerium dioxide. When this method uses high-molecular components, the removal of which requires a high temperature heat treatment and correspondingly high energy consumption per unit of product in industrial process. The latter circumstance leads to large volumes of exhaust gases, a large flow of air for oxidation of the hydrocarbon component of the xerogel and increase the costs of protecting the environment.

US Pat 7,473,408. A method of obtaining single-crystal powders of cerium oxide. 2009

Jun-Seok Noh, Tae-Hyun Kwon, Seung-Beom Cho, Hye-Jeong Hong, Dae-Gon Han reported the hydrothermal method for obtaining fine powders SEO₂with the size of single crystals of 30-300 nm. The synthesis was carried out in an alkaline medium, which used NaOH, KOH or NI-LiOH. As a source of salts of cerium used nitrate or acetate. As organic co-solvents used alcohols With_1-4, ethylene glycol, propylene glycol, butyleneglycol, acetone, glycerine, ethyl acetate, or mixtures thereof. Hydrothermal synthesis was carried out at a temperature of 180-300°C., and the duration ranged from 1 to 12 o'clock as the precipitating used sodium chloride, nitric acid, citric acid or urea.

To not is to Adam of this method include the need to wash the product with distilled water and then, that is not always possible to obtain nanopowders, moreover, it is not possible to obtain powders with crystallite size less than 30 nm.

Patent of the Republic of Korea No. 10-2010-0098927. A method of obtaining a nanopowder of cerium oxide having a narrow size distribution of particles. 2010

Yoido-Dong and co-authors reported obtaining fine powders SEO₂in which particles with a size up to 100 nm is less than 50 wt.%. As the dispersion medium were used polyacrylic acid, and ammonium salts of polyacrylic acids. In the reaction medium pH was 5-10.

The disadvantages of this method include the use of high molecular weight compounds for the preparation of the reaction mixture, a large amount of exhaust gases during the heat treatment and the cost of measures for the protection of the environment.

Patent PRC CN 101164889 Century Nanostructured cerium oxide with a structure of "core-shell" and methods of their preparation. 2010

Li Xing, Lu Bin et al. a method of obtaining particles SEO₂type "core-shell" with a grain size of 400-1000 nm and the size of the kernel 200-700 nm. As the original used a mixed salt of ammonium. Specific surface area of obtained powders was 70-120 m²/, This invention has the advantages: low cost, process organization in the industry is costly, technologically advanced, and the process easy to manage.

The disadvantages of this method should include the fact that it does not provide the nanocrystalline cerium dioxide.

Patent PRC CN 101407331 A. Method of obtaining nanorods cerium oxide. 2009 Zhang Dengsong et al. the hydrothermal method has received nanoparticles of cerium dioxide. As a source of reagent used is a water-soluble salt of cerium, as surfactant - hexadecyldimethylamine, and deposition was performed using ammonia. Upon cooling, the reaction mixture was ultrasonically treated in order to avoid or reduce the likelihood of agglomeration of particles. Hydrothermal synthesis was carried out for 1-3 days at a temperature of 100-180°C. the Product was dried at 60°C. the Obtained particles had a shape of a four - or hexagons with the size of 20-80 nm and a thickness of 3-5 nm.

The disadvantages of this method should include a greater duration of synthesis and low productivity of the process, as well as the use of high molecular weight surfactants and ammonia. The first increases the cost of the process, and the presence in the technological scheme of the second makes the production less environmentally acceptable.

Patent of Ukraine # 93073. A method of obtaining a composition containing a water-soluble nanoparticles of cerium dioxide. 2011 Averatec, Aberbach, Vchebanov proposed a method of obtaining ultrafine casteldaccia cerium with an average size of 2 nm in the composition of the colloidal composition with the addition of polyacrylic acid. The composition is intended to develop on its basis, and pharmaceutical and cosmetic compositions.

Limitations to the applicability of this method should be considered it unacceptable to use to create the technology for the production of large quantities of cerium dioxide as an intermediate for fine-grained ceramics.

Taekyung Yu and others (Aqueous-Phase Synthesis of Single-Crystal Ceria Nanosheets. Angewandte Chemie International Edition, Volume 49, Issue 26, pages 4484-4487, June 14, 2010) was a simple, according to the authors, the method of synthesis of ultrathin single-crystal plates SEO₂a thickness of approximately 2.2 nm and a width of 4 μm. This method is very interesting from the point of view of definition of the experiment, has a high theoretical potential and importance for fundamental research, but at present it is far from the industrial embodiment, since the question remains zoom.

Alexander E.Baranchikov (Lattice expansion and oxygen non-stoichiometry of nanocrystalline ceria. CrystEngComm, 2010, 12, 3531-3533) with co-authors reported on the comparison of texture powders SEO₂obtained by different methods "soft" chemistry: thermal decomposition, hydrothermal, and with the use of microwave processing liquid substrates. As the source were used water-soluble mineral salts include nitrate, chloride, and cerium sulfate, and nitrate of ammonium cerium. Installed the influence of the size of nanoparticles SEO ₂the parameters of the unit cell and an oxygen nonstoichiometry.

To the limitations of the proposed methods should include significant difficulties in their industrial adaptation, as proposed methodology is often focused on the use of unconventional approaches (ultrasonic method), large amounts of fluids (hydrothermal) or is unable to provide high reproducibility when scaling process.

The closest method to the proposed method is proposed in patent RU 2375153, a New method for large-scale production of monodisperse nanoparticles, 2009

Hyeon Taeghwan, Park Gangnam reported method of obtaining monodisperse nanoparticles of metals, metal alloys, metal oxides and oxides of several metals from the following range: Fe, Co, Ti, V, Cr, Mn, Ni, cu, Zn, Y, Zr, Mo, Ru, Rh, Pd, Ag, Cd, Ce, Pt, Au, Ba, Sr, Pb, Hg, Al, Ga, In, Sn and Ge. The key moment of the formation of metal-containing nanoparticles was the formation of the carboxylate complex with aliphatic hydrocarbons_6-25or amine With_6-25; and aromatic hydrocarbons With_6-25or ethers With_6-25. As sources of metals used water-soluble salt. The synthesis was carried out at temperatures 200-380°C. the Molar ratio of carboxylate complex of the metal to the surface-active substances is actually chosen in the range of 1:0.1 to 1:100, preferably 1:0.1 to 1:20. In the application reported receiving 100 g of powders with crystallite size 5-22 nm, and this number is estimated as large.

The disadvantages of this method include the use of high boiling, high-molecular organic compounds, soluble at temperatures above 100°C, which sought to create a synthesis reactor temperature 320-370°C. This requires a high energy production costs. The use of aromatic components in the preparation of reaction mixtures also increases the load on the environment, increases the cost of maintenance of ecological safety of production. In addition, from the data of the patent does not follow that the obtained particles are crystalline cerium dioxide. In addition, proposed in patent method, obtaining 100 g is estimated as large-scale. Apparently, the implementation of this method in production will require the use of reactors a large amount to get a few kilos of products.

The principal difference in the proposal method is that it uses only low molecular weight organic components that form oligomeric gel, including the formation of a future phase of cerium dioxide.

The task of the invention is to create an ecologist who Cesky acceptable low-temperature method of producing ultrafine powders SEO ₂.

The technical result of the invention is to provide a method for obtaining ultra-fine powders of cerium dioxide (crystallite size of less than 80 nm) with a predominantly mesoporous structure (pore size - 2-20 nm).

The proposed method leglization to industrial conditions, and its technological implementation solves the problem of creating an environmentally-friendly technology. In addition, it provides for the creation of cost-effective technologies for producing large amounts of ultrafine powders with desired physico-chemical characteristics: porosity, dispersion, phase composition.

These advantages are achieved due to the following features of the proposed method: budget source reagents, such as cerium nitrate and low molecular weight organic N-containing compounds is N,N-dimethylethylamine, tetraethylammonium hydroxide, monoethanolamine, and in some cases - acetylacetone (1)at the stage of heat treatment the main components of the exhaust gases are carbon dioxide and water vapor (2), no stage filtration and washing simplifies the technological scheme, reduces the cost of material and energy resources (3), the process of the synthesis gel at low temperatures (below 100°C) and subsequent heat treatment at temperatures up to 500°C also reduces energos the waste per unit of product (4).

The technical result allows to get access 95-99% ultra-fine powders mesoporous cerium dioxide with specified morphological characteristics: specific surface area of up to 120 m²/g mesoporous structure with a pore size of 2-20 nm and a crystallite size of less than 80 nm. The share of micropores comprise not more than 10% of the total pore volume and not more than 15% of the specific surface. The microstrain of the obtained crystals of fluorite not exceed 0.5%.

Technical result is achieved by two variants of the method of obtaining mesoporous nano-sized powder of cerium dioxide (options).

On the first version of the technical result is achieved in that in the method of obtaining mesoporous nano-sized powder of cerium dioxide (options), comprising the following stages: receiving water 0,05M solutions of nitrate or cerium acetate; obtaining alcohol solutions of organic N-containing compounds: N,N-dimethylacrylamide, tetraethylammonium hydroxide or monoethanolamine concentration of 0.45-3,30M, 0,37M and 0 M respectively; obtaining Zola in aqueous-organic system; the process of evaporation of water-organic systems; gel formation and heat treatment of the gel in the temperature range 95-500°C on speed graphics that includes multiple intermediate isothermal plots, according to the invention as stabilizat the ditch Zola use the following low-molecular organic N-containing compounds (N): N,N-dimethylethylamine, tetraethylammonium hydroxide or monoethanolamine in the form of alcohol solution at a molar ratio of N/metal equal to 1-20.

On the second version of the technical result is achieved in that in the method of obtaining mesoporous nano-sized powder of cerium dioxide (options), comprising the following stages: receiving water 0,05M solution of the original nitrate cerium; obtaining alcohol solution of N,N-dimethylacrylamide and acetylacetone concentration of 0.29 0,M and 0.69-1,65M respectively; obtaining Zola in aqueous-organic system composed by connecting solutions; the process of evaporation of water-organic systems; the formation of gels and heat treatment of the gel in the temperature range 95-500°C on speed schedule that includes multiple intermediate isothermal sections; according to the invention as stabilizers Zola using N,N-dimethylethylamine at a molar ratio of N,N-dimethylacrylamide/metal equal to 1-20, and is also used as an additional complexing agents the acetylacetone at a molar ratio of the acetylacetone/metal equal to 2-5.

The invention

The invention consists in using a modified Sol-gel method for obtaining nanosized crystalline cerium dioxide. A special feature of this method is that as the stabilizer h is La used the following organic N-containing compounds: N,N-dimethylethylamine, tetraethylammonium hydroxide, monoethanolamine. The process of particle formation Zola takes place in an aqueous-organic medium, the phase boundary. The proposed method allows to obtain ultra-fine powders of cerium dioxide with crystallite size less than 60 nm with a narrow distribution in size.

Created method allows to obtain ultra-fine powders of cerium dioxide with a crystallite size of less than 80 nm and wholly or mainly (more than 50%) with mesoporous structure (pore size - 2-20 nm). These morphological characteristics are achieved due to the fact that

- when the implementation of the modified Sol-gel synthesis as stabilizers Zola uses the following low molecular weight organic N-containing compounds (N): N,N-dimethylethylamine, tetraethylammonium hydroxide, monoethanolamine in the form of alcoholic solutions at a molar ratio of N/metal equals 1-20;

as stabilizers Zola used low molecular weight organic N-containing compounds: N,N-dimethylethylamine, tetraethylammonium hydroxide, monoethanolamine in the form of alcohol solution (molar ratio N/metal=1-20), but in addition additionally used as an additional complexing agents the acetylacetone (molar ratio acetylacetone /metal=2-5). In both cases,

- saloobrazovanie performed at the temperature of 70°C and stirring;

the gelation is carried out at a temperature of 93-95°C and stirring;

- heat treatment of the obtained gel is conducted in a stepwise schedule in the temperature range 98-500°C, at 500°C, the powder was incubated for 1 h

EXAMPLES

Figure 1 shows the diffraction patterns of powders of cerium dioxide, obtained on the diffractometer DRON-3 and DRON-3M using uKα-radiation. *The diffraction pattern obtained using Kα-radiation. The crystallite size was calculated using the Rietveld method.

The investigation of surface and porosity of the powders was performed using an analyzer, specific surface area NOVA 2200. Specific surface area was determined by the method of Brunauer-Emmett-teller (BET)and pore sizes by the method of Barrett-Joyner-Halenda (BCH) at a temperature of -196°C.

EXAMPLE 1.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved is 3.08 ml of N,N-dimethylacrylamide (0.015 mol) under stirring on a magnetic stirrer (400 rpm) in accordance with the s 40 min at 70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (600 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (600 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained of 2.23 g (0.013 mole) of powder CEO₂.

In figure 1, the diffraction pattern 1 corresponds to the sample powder of cerium dioxide No. 1. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 12 nm. Figure 2 shows curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 1. According to the adsorption-desorption of N₂its porous structure was represented mainly by mesopores (figure 2A), and not more than 10% of the surface was provided by micropores. The specific surface of the powder was 90,8 m²/g with a narrow distribution of pore size in the interval for the Le 5-12 nm (figure 2B).

EXAMPLE 2.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved is 3.08 ml of N,N-dimethylacrylamide (0.015 mol) under stirring on a magnetic stirrer (400 rpm) for 40 min at 70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (400 rpm) at a temperature of 90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (400 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed at 500°C without pre-high temperature (rapid hardening) within 2 hours Was obtained 2.24 g (0,013 mol) CeO₂.

In figure 1, the diffraction pattern 2 corresponds to the sample powder of cerium dioxide No. 2. By Dan is haunted by x-ray diffraction, the powder of cerium dioxide with the fluorite structure had an average crystallite size of 17 nm. Figure 3 shows curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 2. According to the adsorption-desorption of N₂its porous structure was represented mainly by mesopores (figure 3A), and no more than 5% of the surface was provided by micropores. The specific surface of the powder was 30.7 m²/g with a narrow distribution of pore size in the range of 3.5-4.0 nm (figure 3b).

EXAMPLE 3.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (500 rpm) for 40 min at 90°C.

In 30 ml of ethanol (0,515 mol) was dissolved is 3.08 ml of N,N-dimethylacrylamide (0.015 mol) under stirring on a magnetic stirrer (500 rpm) for 40 min at 70°C.

The resulting solutions were combined and stirred the mixture for 5 min on a magnetic stirrer (500 rpm) at a temperature of 88-90°C. Then the solution was placed in an autoclave and stirred (1000 rpm) at 95-98°C. and autogenous pressure (~2.5 ATM) in ECENA 12 PM Then the reaction mixture was filtered.

The precipitate was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained 2.24 g (0,013 mol) powder CEO₂.

In figure 1, the diffraction pattern 3 corresponds to the sample powder of cerium dioxide No. 3. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 12 nm. Figure 4 shows curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 3. According to the adsorption-desorption of N₂its porous structure was almost completely mesoporous (figure 4A). The specific surface of the powder was 84,7 m²/g with a narrow distribution of pore size in the range of 5-8 nm (figure 4B).

EXAMPLE 4.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (500 rpm) for 40 min at 90°C.

In 30 ml ETANA is a (0,515 mol) was dissolved is 3.08 ml of N,N-dimethylacrylamide (0.015 mol) under stirring on a magnetic stirrer (500 rpm) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 5 min on a magnetic stirrer (500 rpm) at a temperature of 88-90°C. Then the solution was placed in an autoclave and subjected to hydrothermal treatment (800 rpm) at 127-130°C. and autogenous pressure for 3 h Then the reaction mixture was filtered.

The precipitate was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained of 2.23 g (0,013 mol) powder CEO₂.

In figure 1, the diffraction pattern 4 corresponds to the sample powder of cerium dioxide No. 4. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 12 nm.

EXAMPLE 5.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 5,16 g (0.015 mol) of the monohydrate of cerium acetate (CE(CH₃Soo)₃·H₂O) under stirring on a magnetic stirrer (500 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved is 3.08 ml of N,N-dimethylacrylamide (0.015 mol) under stirring on a magnetic mesh is ke (500 rpm) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (500 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (500 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained of 2.23 g (0,013 mol) powder CEO₂.

In figure 1, the diffraction pattern 5 corresponds to the sample powder of cerium dioxide No. 5. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 9 nm. Figure 5 shows curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 5. According to the adsorption-desorption of N₂its porous structure was represented mainly by mesopores (figure 5A), and not more than 10% of the surface was provided by micropores. The specific surface of the powder was 113,1 m²/g with a narrow distribution of pore size in the intervals in which f is 3.5-4.0 nm (figure 5B).

EXAMPLE 6.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved 15,39 ml of N,N-dimethylacrylamide (0,075 mol) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (600 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (600 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained 2.15 g (of 0.0125 mole) of powder CEO₂.

In figure 1, the diffraction pattern 6 corresponding to the sample powder of cerium dioxide No. 6. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 25 nm. Figure 6 shows the curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 6. According to the adsorption-desorption of N₂its porous structure was represented mainly by mesopores (figure 6A), and not more than 20% of the surface was provided by micropores. The specific surface of the powder was 35.5 m²/g with a narrow distribution of pore size in the range of 3-5 nm (figure 6b).

EXAMPLE 7.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved 30,78 ml of N,N-dimethylacrylamide (0,150 mol) under stirring on a magnetic stirrer (400 rpm) for 40 min at 70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (600 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C at constant p is remesiana on a magnetic stirrer (600 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by solidification of the mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained of 2.23 g (0,013 mol) powder CEO₂.

In figure 1, the diffraction pattern 7 corresponds to the sample powder of cerium dioxide No. 7. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 22 nm. Figure 7 shows curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 7. According to the adsorption-desorption of N₂its porous structure was represented mainly by mesopores (figure 7a), and not more than 10% of the surface was provided by micropores. The specific surface of the powder was 48.8 m²/g with a narrow distribution of pore size in the range of 3-5 nm (figure 7b).

EXAMPLE 8.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) R is was storyli 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO ₃)₃·6N₂O) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved 61,56 ml of N,N-dimethylacrylamide (0,300 mol) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (600 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (600 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained 2.15 g (of 0.0125 mole) of powder CEO₂.

In figure 1, the diffraction pattern 8 corresponds to the sample powder of cerium dioxide No. 8. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 18 nm. Figure 8 shows curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 8. To the authorized adsorption-desorption of N ₂its porous structure was represented mainly by mesopores (figure 8A) with a pore diameter of 2-3 and 10-12 nm (figure 8b), and not more than 10% of the surface was provided by micropores. The specific surface of the powder was 71.4 m²/year

EXAMPLE 9.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (400 rpm) for 40 min at 90°C.

In 30 ml of ethanol (0,515 mol) was dissolved to 10.6 ml of 20% aqueous solution of tetraethylammonium hydroxide (0.015 mol) under stirring on a magnetic stirrer (400 rpm) for 40 min at 70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (600 rpm) at a temperature of 90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (600 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed the do in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained 2.15 g (of 0.0125 mole) of powder CEO₂.

In figure 1, the diffraction pattern 9 corresponds to the sample powder of cerium dioxide No. 9. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 15 nm. Figure 9 shows the curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 9. According to the adsorption-desorption of N₂the powder had a mesoporous structure (figure 9a), its specific surface area amounted to 60.6 m²/g with pore sizes in the range of 2-4 nm (figure 9b). Not more than 5% of the surface was provided by micropores.

EXAMPLE 10.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (500 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved to 10.6 ml of 20%aqueous solution of tetraethylammonium hydroxide (0.015 mol) under stirring on a magnetic stirrer (Ob/min) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 5 min on a magnetic stirrer (500 rpm) at a temperature of 88-90°C. Then the solution was placed in an autoclave and subjected to hydrothermal treatment (800 rpm) at 127-130°C. and autogenous pressure for 3 h Then the reaction mixture was filtered.

The precipitate was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Received 2.14 g (of 0.0125 mole) of powder CEO₂.

In figure 1, the diffraction pattern 10 corresponds to the sample powder of cerium dioxide No. 10. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 11 nm.

EXAMPLE 11.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 5,16 g (0.015 mol) of the monohydrate of cerium acetate (CE(CH₃Soo)₃·H₂O) under stirring on a magnetic stirrer (500 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved to 10.6 ml of 20% aqueous solution of tetraethylammonium hydroxide (0.015 mol) when paramesh the processes on a magnetic stirrer (500 rpm) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (500 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (500 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Was obtained 2,12 g (of 0.0125 mole) of powder CEO₂.

In figure 1, the diffraction pattern 11 corresponds to the sample powder of cerium dioxide No. 11. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 8 nm. Figure 10 shows the curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 11. According to the adsorption-desorption of N₂the powder had a mesoporous structure (figure 10A), its specific surface area was 129,0 m²/g with pore sizes in the range of 4.0 to 4.2 nm (figure 10B). Not more than 15% of the surface was provided by micropores.

EXAMPLE 12.

The dioxide powder C is Riya received 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved in 0.9 ml of monoethanolamine (0.015 mol) under stirring on a magnetic stirrer (400 rpm) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (600 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (600 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Received 2,13 g (of 0.0125 mole) of powder CEO₂.

In figure 1, the diffraction pattern 12 corresponds to the sample powder of cerium dioxide No. 12. According to x-ray diffraction, Orasac CERIC oxide with a fluorite structure had an average crystallite size of 21 nm. Figure 11 shows the curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 12. According to the adsorption-desorption of N₂the powder had a mesoporous structure (figure 11a), its specific surface area was 23.4 m²/g with pore sizes in the range of 3.5-4.0 nm (figure 11b). No more than 20% of the surface was provided by micropores.

EXAMPLE 13.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (500 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved in 0.9 ml of monoethanolamine (0.015 mol) under stirring on a magnetic stirrer (500 rpm) for 40 min at a temperature 69-70°C.

The resulting solutions were combined and stirred the mixture for 5 min on a magnetic stirrer (500 rpm) at a temperature of 88-90°C. Then the solution was placed in an autoclave and subjected to hydrothermal treatment (800 rpm) at 128-130°C. and autogenous pressure (~2.5 ATM) for 3 h Then the reaction mixture was filtered.

The precipitate was transferred into a porcelain or corundum Cup and p which were memali in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Received 2,12 g (of 0.0125 mole) of powder CeO₂.

In figure 1, the diffraction pattern 13 corresponds to the sample powder of cerium dioxide No. 13. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 12 nm. Figure 12 shows the curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 13. According to the adsorption-desorption of N₂the powder had a mesoporous structure (figure 12A), its specific surface area was 88,9 m²/g with pore sizes in the range of 6-7 nm (figure 126). No more than 3% of the surface was provided by micropores.

EXAMPLE 14.

The powder of cerium dioxide obtained in 1 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 5,16 g (0.015 mol) of the monohydrate of cerium acetate (CE(CH₃Soo)₃·H₂O) under stirring on a magnetic stirrer (500 rpm) for 40 min at a temperature of 88-90°C.

In 30 ml of ethanol (0,515 mol) was dissolved in 0.9 ml of monoethanolamine (0.015 mol) under stirring on a magnetic stirrer (500 rpm) for 40 min when the temperature is e 69-70°C.

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (500 rpm) at a temperature of 88-90°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (500 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Received 2,13 g (of 0.0125 mole) of powder CEO₂.

In figure 1, the diffraction pattern 14 corresponds to the sample powder of cerium dioxide No. 14. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 11 nm. Figure 13 shows curves of adsorption-desorption of N₂(a) and size distribution of pores (b) a powder of cerium dioxide No. 14. According to the adsorption-desorption of N₂the powder had completely mesoporous structure (figure 13a), its specific surface area was 49.2 m²/g with pore sizes in the range of 3.0-3.5 nm (figure 13B).

EXAMPLE 15.

The powder of cerium dioxide obtained by the 2 option.

To obtain RA the solutions was used deionized water, obtained through reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (200-300 rpm) for 40 min at a temperature of 88-90°C.

To 7,4 ml of acetylacetone (0,072 mol) was added 6,16 ml of N,N-dimethylacrylamide (0.03 mol) with stirring on a magnetic stirrer (200-300 rpm) for 20 min at a temperature of 88-90°C. the Solution was cooled to 70°C., after which it was added 30 ml of ethanol (0,515 mol) and was stirred for 20 minutes

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (200-300 rpm) at a temperature 69-70°C

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (200-300 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Obtained 2,32 g (0,013 mol) of cerium dioxide.

In figure 1, the diffraction pattern 15 corresponds to the sample powder di is xida cerium No. 15. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 36 nm. Figure 14 shows curves of adsorption-desorption of N₂(a) and the distribution curve of the pore size (b) powder of cerium dioxide No. 15. According to the adsorption-desorption of N₂its porous structure was represented mainly by mesopores (figure 14a) with a 3.5-30 nm (figure 14b). The specific surface of the powder was 15.4 m²/g and not more than 10% of the surface was provided by micropores. Figure 14b presents the micrograph of the powder of cerium dioxide, No. 15, obtained with a transmission electron microscope EM-301 Philips. You can see that the particle size is 10-100 nm, most often they are larger than 40 nm.

EXAMPLE 16.

The powder of cerium dioxide obtained by the 2 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (200-300 rpm) for 40 min at a temperature of 88-90°C.

3.7 ml of acetylacetone (being 0.036 mol) was dissolved is 3.08 ml of N,N-dimethylacrylamide (0.015 mol) under stirring on a magnetic stirrer (200-300 rpm) for 20 min at te is the temperature of 90°C. The solution was cooled to 70°C., after which it was added 30 ml of ethanol (0,515 mol) and was stirred for 20 minutes

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (200-300 rpm) at a temperature 69-70°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (200-300 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using a speed graph of temperature rise. At 500°C the resulting product was kept for 1 h Obtained of 2.34 g (of 0.014 mol) of cerium dioxide.

In figure 1, the diffraction pattern 16 corresponds to the sample powder of cerium dioxide No. 16. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 46 nm. Figure 15 shows the curves of adsorption-desorption of N₂(a) and the distribution curve of the pore size (b) powder of cerium dioxide No. 16. According to the adsorption-desorption of N₂in its porous structure has a large share was mesopores (figure 15A) with a 3.5-4.0 nm (figure 156). The specific surface of the powder is and was 8.0 m ²/g and not more than 50% of the surface was provided by micropores.

EXAMPLE 17.

The powder of cerium dioxide obtained by the 2 option.

To obtain solutions was used deionized water obtained by reverse osmosis Raifil.

In 300 ml of deionized water (16,670 mol) was dissolved 6,51 g (0.015 mol) of uranyl nitrate cerium (CE(NO₃)₃·6N₂O) under stirring on a magnetic stirrer (200-300 rpm) for 40 min at a temperature of 88-90°C.

To 2.5 ml of acetylacetone (0,024 mol) was added 2,05 ml of N,N-dimethylacrylamide (0,010 mol) under stirring on a magnetic stirrer (200-300 rpm) for 20 min at a temperature of 88-90°C. the Solution was cooled to 70°C., after which it was added 30 ml of ethanol (0,515 mol) and was stirred for 20 minutes

The resulting solutions were combined and stirred the mixture for 30 min on a magnetic stirrer (200-300 rpm) at a temperature 69-70°C.

Then the reaction mixture was evaporated at 93-95°C with constant stirring on a magnetic stirrer (200-300 rpm). Evaporation was performed until then, until it began a sharp rise in temperature (exothermic effect), which was accompanied by zagustevanii mixture with the formation of a gel.

The obtained gel was transferred into a porcelain or corundum Cup and placed in a muffle furnace, where heat treatment was performed using stupen is atogo graph of temperature rise. At 500°C the resulting product was kept for 1 h Obtained 2,33 g (of 0.014 mol).

In figure 1, the diffraction pattern 17 corresponds to the sample powder of cerium dioxide No. 17. According to x-ray diffraction, powder of cerium dioxide with the fluorite structure had an average crystallite size of 44 nm. Figure 16 shows the curves of adsorption-desorption of N₂(a) and the distribution curve of the pore size (b) powder of cerium dioxide No. 17. According to the adsorption-desorption of N₂in its porous structure was dominated by mesopores (figure 16A) with a 3.5-4.0 nm (figure 16B). The specific surface of the powder was 9.9 m²/g and not more than 30% of the surface was provided by micropores. Figure 16B presents a micrograph of the powder of cerium dioxide, No. 17, obtained with a transmission electron microscope EM-301 Philips. You can see that the particle size is 20-80 nm, most often they are larger than 50 nm.

Table 1 shows the morphological characteristics of the powders of cerium dioxide (according to x-ray diffraction and adsorption-desorption of N₂).

1. The method of obtaining mesoporous nano-sized powder of cerium dioxide, including the steps:
- getting water 0,05M solution of cerium nitrate or cerium acetate, using CE(NO₃)₃·6N₂O or CE(CH₃Soo)₃·H₂O accordingly,
- obtaining alcohol solution of the stabilizer Zola organic N-containing compounds: N,N-dimethylacrylamide, tetraethylammonium hydroxide or monoethanolamine concentration of 0.45-3,30M, 0,37M and 0 M respectively,
- getting Zola in aqueous-organic system by connecting composed of rest the ditch,
the process of evaporation of water-organic systems,
- formation of a gel,
- heat treatment of the gel in the temperature range 95-500°C on speed schedule that includes several intermediate isothermal plots
characterized in that the stabilizer is Zola use one of the following low-molecular organic N-containing compounds (N): N,N-dimethylethylamine, tetraethylammonium hydroxide, monoethanolamine in the form of alcohol solution at a molar ratio of N/metal equal to 1-20.

2. The method according to claim 1, characterized in that saloobrazovanie carried out at a temperature of 70°C and stirring.

3. The method according to claim 1, characterized in that the gelation is carried out at a temperature of 93-95°C and stirring.

4. The method according to claim 1, characterized in that the heat treatment of the obtained gel is conducted in a stepwise schedule in the temperature range 98-500°C, at 500°C, the powder was incubated for 1 h

5. The method of obtaining mesoporous nano-sized powder of cerium dioxide, including the steps:
- getting water 0,05M solution of cerium nitrate, using CE(NO₃)₃·6N₂Oh,
- obtaining alcohol solution (ethanol) N,N-dimethylacrylamide and acetylacetone concentration of 0.29 0,M and 0.69-1,65M respectively,
- getting Zola in aqueous-organic system as a result of connections made solutions
- UPrev is the aqueous-organic system, the gel formation and heat treatment of the gel in the temperature range 95-500°C on speed schedule that includes multiple intermediate isothermal plots
characterized in that the stabilizer is Zola's use of low molecular weight organic N-containing compound (N) when the molar ratio N/a metal equal to 1-20, and is also used as an additional complexing agents the acetylacetone at a molar ratio of the acetylacetone/metal equal to 2-5.

6. The method according to claim 5, characterized in that saloobrazovanie carried out at a temperature of 70°C and stirring.

7. The method according to claim 5, characterized in that the gelation is carried out at a temperature of 93-95°C and stirring.

8. The method according to claim 5, characterized in that the heat treatment of the obtained gel is conducted in a stepwise schedule in the temperature range 98-500°C, at 500°C, the powder was incubated for 1 h