Method of producing nanoporous material for sensitive elements of gas sensors and nanoporous material obtained using said method

FIELD: chemistry.

SUBSTANCE: invention relates to production of nanoporous materials based on silicon-aluminium aerogels and can be in making sensitive elements of measurement devices of gas sensors, used in power engineering, chemical industry, as well as analysis of expired air in medicine. Disclosed is a method of producing nanoporous material, which is a composite silicon-aluminium aerogel composition SiO2/Al2O3, using a sol-gel process, in which to produce aluminium oxide sol a product of reacting aluminium nanopowder and/or aluminium nitride composition with particle size from 50 to 500 nm with water is used, which is then peptized to obtain sol. Also disclosed is a corresponding nanoporous material.

EFFECT: technical result is obtaining nanoporous material based on silicon-aluminium aerogel with required charge properties: zeta-potential from -20 to -26 mV, charge surface density from 10-3 to 10-2 C/m2, in pores of which it is possible to perform transformation (change) of spectra of molecules of gases, as well as producing an aerogel without use of supercritical drying during its synthesis.

9 cl, 4 dwg, 1 tbl, 5 ex

 



 

Same patents:

FIELD: chemistry.

SUBSTANCE: present invention relates to a composition for improving formation of crystal agglomerates during crystallisation from a mother solution, which includes: one or a mixture of fatty acids, esters thereof, amides or precursors in amount of 0.1-30%, white kerosene in amount of 15.1-50% and water, wherein said components together form an emulsion. The present invention also relates to a method of improving formation and extraction of crystal agglomerates during crystallisation from a mother solution, which includes the following steps: (i) adding a crystal growth-modifying composition to the mother solution according to claim 1 in an amount which is effective for increasing the size of crystal agglomerates; (ii) distributing the crystal growth-modifying composition in the mother solution and (iii) depositing crystal agglomerates from the mother solution.

EFFECT: obtaining large aluminium hydroxide crystals.

11 cl, 5 ex, 5 tbl

FIELD: chemistry.

SUBSTANCE: inventions can be used in chemical and electronic industry. Method of obtaining aluminium α-oxide for obtaining sapphire monocrystal includes stage at which 100 weight parts of aluminium (I) α-oxide and 25-235 weight parts of aluminium (II) α-oxide are mixed. Aluminium (I) α-oxide has specific surface area from 0.1 to 5 m2/g and volume density 1.5 g/cm3 or more. Aluminium (II) α-oxide is formed from sintered particles and has specific surface area 1 m2/g or less and relative density 85% or higher, and each of sintered particles has volume 0.01 cm3 or more.

EFFECT: inventions make it possible to reduce quantity of adsorbed water, reduce crucible oxidation and increase efficiency of monocrystalline sapphire obtaining.

6 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical and electronic industry. The volume per particle of α-aluminium oxide for producing monocrystalline sapphire is not less than 0.01 cm3, relative density is not less than 80%, bulk density of the aggregate is 1.5-2.3 g/cm3, and its shape is any one of spherical, cylindrical and briquette-like.

EFFECT: invention reduces the amount of adsorbed water, reduces crucible oxidation and improves the efficiency of producing monocrystalline sapphire.

3 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an ammonia synthesis catalyst. Said catalyst is a supported metal catalyst which is deposited on a mayenite-type compound, containing conduction electrons in concentration of 1015 cm-3 or higher and serving as a support for the ammonia synthesis catalyst. The invention also relates to a method of producing said catalyst and an ammonia synthesis method using said catalyst.

EFFECT: disclosed catalyst enables synthesis of ammonia with high efficiency in mild conditions.

7 cl, 1 dwg, 4 tbl, 11 ex

FIELD: chemistry.

SUBSTANCE: method includes processing aluminium salt with a solution of an alkaline reagent, washing the sediment and its thermal processing. As aluminium salt applied are crystals of aluminium hexahydrate chloride, which are processed with the excess of a water ammonia solution at a temperature of 20-80°C with the formation of boehmite. Thermal processing is realised at 450-650°C until aluminium oxide is formed.

EFFECT: invention makes it possible to obtain aluminium oxide in the from of separate particles with a specified structure and properties.

2 dwg

FIELD: metallurgy.

SUBSTANCE: invention relates to methods for obtaining amorphous mesoporous aluminium hydroxide with a laminated fibrous microstructure. A method for obtaining amorphous mesoporous aerogel of aluminium hydroxide with a laminated fibrous oriented nanostructure involves the performance of a synthesis reaction of aluminium hydroxide aerogel in a tight container by the treatment of a binary melt with a steam-gas flow based on a mixture of inert and (or) low-active gases with a water vapour at the melt temperature of 280-1000°C. As the binary melt, bismuth with the aluminium content of 0.05-7.00 wt % is used.

EFFECT: invention allows improving technical and economic indices at the production of nanostructured aerogel AlOOH.

1 dwg, 1 tbl

FIELD: power industry.

SUBSTANCE: invention relates to power engineering, and namely to a processing method of ash-slag materials (ASM) of coal-fired power stations, and can be used when obtaining aluminous concentrate and belite slurry for purposes of the aluminuos and construction industry. The processing method of the ash-slag materials of the coal-fired power stations involves activation of the ash-slag materials and separation of processing products so that silica and alumina can be obtained. The method differs by the fact that hydraulic classification of th ash-slag materials is performed as per Class 45 mcm so that two fractions are obtained: +45 mcm and slightly magnetic fraction -45 mcm, fraction +45 is subject to magnetic separation so that magnetic concentrate and tail ends of magnetic separation are obtained; the magnetic separation tail ends are subject to flotation so that carbon concentrate and floatation tail ends are obtained; the floatation tail ends with classification of less than 45 mcm and slightly magnetic fraction -45 is combined into a common fraction with further dilution of the common fraction in a sodium hydroxide solution, separation of the obtained pulp into a cake rich in alumina, and a sodium silicate solution; after that, the cake is processed into alumina, and the sodium silicate solution is recovered by lime.

EFFECT: eliminating disadvantages of known technical solutions by changing implementation of the method and increasing full ASM processing owing to obtaining quality target products from them in the form of alumina and high-disperse silica, which are maximum cleaned from hazardous impurities limited by GOST (manganese, chrome, sulphur, zinc, iron, phosphorus, etc).

2 cl, 9 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: method of producing alpha-phase of aluminium oxide includes distillation purification of aluminium alcoholate, hydrolysis thereof and synthesis of alpha-phase of aluminium oxide. Distillation purification of the aluminium alcoholate is carried out in a current of inert gas, and hydrolysis of the aluminium alcoholate and synthesis of the alpha-phase of aluminium oxide is carried out in a supercritical reactor.

EFFECT: method increases degree of purity of the alpha-phase of aluminium oxide, increases output and reduces power consumption per unit product while increasing packed density of the alpha-phase of aluminium oxide.

3 cl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: to obtain corundum microfilm layer of corundum is precipitated on film base or drum from material with reduced adhesion, as such applied is fluoroplast, after that, corundum film is removed from film base or drum. Layer of corundum can be precipitated on film base from sublimated material, as such applied is fluoroplast-4, with further sublimation of base. Also corundum layer is precipitated on film base from soluble material, as such applied is nitrocellulose, with further dissolution of base. In addition to this, to obtain corundum microfilm corundum layer is precipitated on film base or drum from melting material, as such applied is tin, after which film base or drum is melted and corundum layer is separated.

EFFECT: invention makes it possible to obtain corundum microfilm of higher strength and elasticity.

6 cl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method for synthesis of nanosize composite metal oxide and a composite metal oxide obtained using said method. The method involves adding a dispersant to a colloid with nanoparticles of composite cerium dioxide with average nanoparticle diameter of 10 nm or less, adding a dispersant to a colloid with aluminium oxide nanoparticles with average nanoparticle diameter of 10 nm or less, separately feeding the colloid with composite cerium dioxide nanoparticles, to which a dispersant has been added, and the colloid with aluminium oxide nanoparticles, to which a dispersant has been added, into a high-speed mixer, synthesis of aluminium oxide-composite cerium dioxide nanoparticles by facilitating interaction in a microspace of the composite cerium dioxide nanoparticles and aluminium oxide nanoparticles and applying a shearing force with degree of shear of 17000 s-1 or higher to the aluminium oxide-composite cerium dioxide nanoparticles.

EFFECT: synthesis of more homogeneous nanocomposite metal oxides with improved properties.

6 cl, 6 dwg, 2 tbl, 8 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to methods for obtaining colloids of a metal oxide (versions), namely silicon dioxide, as well as to colloids themselves. The method involves addition of a chemically active metal oxide to a reaction tank at optimum mass velocity of addition of the metal oxide, which is based on a mathematical model that considers (i) particle nucleation rate, (ii) rate of metal oxide deposition on existing particles of metal oxide and (iii) growth of metal oxide particles in the reaction tank. Mass velocity of addition of metal oxide increases as a reaction time function. Introduction of inoculating particles of metal oxide to the reaction tank is performed prior to a stage of addition of the chemically active metal oxide. An optimum mass velocity of addition of metal oxide q is presented by the following formula: q=(3moGr/Dpo3)(Dpo+Grt)2, where: mo represents mass of metal oxide particles in the reaction tank in grams; Gr represents growth rate of metal oxide particles for metal oxide particles in the reaction tank as is determined as per increase of particle diameter, in nanometres per hour; Dpo represents average diameter of metal oxide particles in nanometres; t represents time in hours. Gr is within approximately 10 to approximately 50 nm/hours and q is within approximately 10.6 to approximately 52.8 g/1000 m2-hour during at least some part of the reaction period.

EFFECT: methods according to the invention are more effective due to reduction of reaction periods necessary to obtain colloids of metal oxide.

25 cl, 5 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: hybrid sol, containing nano- and microparticles, is obtained by mixing a silica sol containing nano- and microparticles and a refractory metal sol containing microparticles in a ratio where the refractory metal oxide in the hybrid sol ranges from 0.1 to 20 wt %. The nano-micro silica sol is formed by hydrolytic polycondensation of tetraethoxysilane at temperature of 20-40°C; aqueous ammonia solution is added to the tetraethoxysilane at a rate of 1-10 ml/min, followed by holding for 5-24 hours and concentrating the obtained sol to solid phase content of 25-40 wt %. The refractory metal oxide sol is obtained via hydrolytic condensation by adding an alcohol solution of refractory metal alkoxides in a water-alcohol solution at a rate of 1-10 ml/min, followed by holding for 5-24 hours and concentrating the obtained sol to solid phase content of not less than 3 wt %.

EFFECT: invention enables to obtain nano- and microstructured hybrid sols based on tetraalkoxysilane and hydrolysed refractory metal alkoxides.

2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to production of silicate materials. Disclosed is a method of producing inverted-phase hydrophobisated polysilicate sorbents, which includes reaction of a hydrophilic silicate component with an amphiphilic silicate component in an aqueous medium. Co-condensation of said components is carried out with molar ratio of water to the sum of the silicate components of 124-250. An acidic and/or alkaline component is also added to the reaction mixture until polysilicate hydrogel forms. The obtained sorbent is intended for use as a filter medium and as an enterosorbent.

EFFECT: obtaining three-dimensional hydrogel of polysilicic acid containing hydrophilic and hydrophobic groups in an aqueous medium.

17 cl, 3 tbl, 1 dwg, 16 ex

FIELD: chemistry.

SUBSTANCE: claimed invention relates to suspensions, containing very small amount of salts and containing, at least, one precipitated silicon oxide. Claimed is method of obtaining suspensions which have low content of salts and include, at least, one precipitated silicon oxide, including the following stages: provision of suspension, containing, at least, one precipitated silicon oxide; bringing suspension pH to value 0.5-5, if pH of suspension, obtained at the previous state, is not in the said interval; purification of suspension by means of electrodialysis, with device for electrodialysis including one or more electrodialysis cells, in each of which product-containing area is separated from catholyte-containing area by means of cation-exchange membrane and distance between electrodes constitutes from 2 to 200 mm; and application of potential from 5 to 1000 V. Also claimed are: suspension obtained by said method, cell for electrodialysis and device which contains it, as well as suspension application. Obtained suspensions are suitable for obtaining coatings for paper in manufacturing information carriers with application of inkjet printing or for obtaining dried precipitated silicon oxides.

EFFECT: method makes it possible to obtain suspensions, containing precipitated silicon oxide with content of sodium sulphate lower than 1000 ppm.

21 cl, 1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the chemical industry and can be used to produce composites which are used in photocatalytic processes as catalysts of oligomerisation of olefins and polymerisation of ethylene. The composite material based on silica gel is obtained by precipitation of silicon dioxide from sodium silicate in the presence of titanium dioxide or copper oxide by bubbling of carbon dioxide through the thickness of the suspension at the atmospheric pressure to form the composite material with the type "core (silicon dioxide)/shell (metal oxide)". The method can be used both in the laboratory and in industrial conditions.

EFFECT: invention enables to simplify the process of obtaining a composite, as the need for complex instrumental execution of the process is eliminated, connected with the use of high pressure of carbon dioxide in obtaining the silica gel, as well as environmental safety of the technology, which is connected to the lack of carbon dioxide emissions, achieved by its repeated use.

3 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. Silica gel is obtained by acidifying an alkali metal silicate solution by adding natural sulphur water. The sodium sulphide Na2S obtained during the reaction can be used to deposit heavy metal ions in electroplating industry.

EFFECT: invention reduces power consumption.

2 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of obtaining mineral silicic water (MSW), intended for application for medical purposes. The method of obtaining includes hydrolysis of tetraethoxysilane in the TEOS mixture: ethanol: water, acidified by HCl. Nanosol is obtained at a temperature of 55-65°C for 1.5 hours with evaporation of ethanol to the volume reduction by 1/3, then, dilution of the obtained nanosol with a physiological solution NaCl is carried out in 2 steps with equal portions of the physiological solution, preliminarily heated to 40-50 in a ratio of volumes of the initial nanosol: physiological solution 1:7 with 15-minute interval. After each dilution a temperature of the solution is kept in the range of 55-65°C.

EFFECT: increase of the compound application efficiency.

1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of obtaining silicon-dioxide-containing polyol dispersions, used to obtain polyurethane materials. Claimed is the method of obtaining silicate-containing polyols, which includes stages: (i) mixing water silica sol (K) with the average diameter of particles from 1 to 150 nm, content of silicic acid, calculated as SiO2, from 1 to 60 wt % and pH value from 1 to 6 depending on the used content of SiO2 and from 0.1 to 20-fold amount calculated per water of, at least, one organic solvent (L); (ii) mixing the obtained mixture with polyol; (iii) at least, partial distillation of an organic solvent (L) and water; (iv) mixing, at least, with one compound (S), which contains, at least, one at least once alkoxilated silyl group and, at least, one alkyl, cycloalkyl or aryl substituent, which can contain heteroatoms, and the said substituent contains, if necessary, a group, reactionable with respect to alcohol, amine or isocyanate, in an amount from 0.1 to 30 mol % calculated per SiO2 content; (v) if necessary, bringing pH value of silicate-containing polyol to a value of 7 to 12 by addition of a strongly basic compound, and the stage (v) can be realised between stages (iii) and (iv).

EFFECT: claimed method makes it possible to obtain low-viscous dispersions of silicon dioxide particles from commercially available water sols of silicon dioxide.

16 cl, 3 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to a method of obtaining silicon-dioxide-containing polyol dispersions, used to obtain polyurethane materials. Claimed is the method of obtaining silicate-containing polyols, which includes stages: (i) mixing water silica sol (K) with the average diameter of particles from 1 to 150 nm, content of silicic acid, calculated as SiO2, from 1 to 60 wt % and pH value from 1 to 6 depending on the used content of SiO2 and from 0.1 to 20-fold amount calculated per water of, at least, one organic solvent (L); (ii) mixing the obtained mixture with polyol; (iii) at least, partial distillation of an organic solvent (L) and water; (iv) mixing, at least, with one compound (S), which contains, at least, one at least once alkoxilated silyl group and, at least, one alkyl, cycloalkyl or aryl substituent, which can contain heteroatoms, and the said substituent contains, if necessary, a group, reactionable with respect to alcohol, amine or isocyanate, in an amount from 0.1 to 30 mol % calculated per SiO2 content; (v) if necessary, bringing pH value of silicate-containing polyol to a value of 7 to 12 by addition of a strongly basic compound, and the stage (v) can be realised between stages (iii) and (iv).

EFFECT: claimed method makes it possible to obtain low-viscous dispersions of silicon dioxide particles from commercially available water sols of silicon dioxide.

16 cl, 3 tbl

FIELD: chemistry.

SUBSTANCE: invention can be used in paint industry. The method of producing an aqueous dispersion of silanised colloidal particles of silica in an aqueous medium involves mixing a) at least one silane compound with epoxy functionality, b) at least one silane compound without epoxy functionality, capable of modifying colloidal particles of silica, and c) colloidal particles of silica to form an aqueous dispersion of silanised colloidal particles of silica containing silane compounds from a) and b). The weight ratio of a) and b) to silica ranges from about 0.01 to 1.5.

EFFECT: invention increases stability of colloidal silica dispersions, water resistance and hardness of lacquer coatings.

13 cl, 15 tbl

FIELD: chemistry.

SUBSTANCE: first step includes obtaining low-hydroxylated insoluble fullerenols by reacting concentrated fullerene solution in o-xylene with aqueous ammonia solution in the presence of a tetrabutylammonium hydroxide phase-transfer catalyst at 35-40°C. At the second step, the obtained low-hydroxylated insoluble fullerenols are hydroxylated to transform them into a water-soluble form by mixing with 6-15% aqueous hydrogen peroxide solution and heating for 4-5 hours at 65°C. Water-soluble fullerenols are then precipitated from an alcohol-containing solution.

EFFECT: simplifying the method while preserving quality characteristics and full extraction of the end product.

2 cl, 1 dwg, 4 tbl, 3 ex

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