Catalyst for low-temperature oxidation of carbon monoxide and preparation method thereof
SUBSTANCE: disclosed catalyst for low-temperature oxidation of carbon monoxide, which is silver deposited on a silicon dioxide surface in amount of 1-16% of the weight of the catalyst. The catalyst contains silver in the form of nanoparticles with a size smaller than 6 nm, which are uniformly distributed on the surface of mesoporous silica gel with specific surface area of 50-200 m2/g and pore size of 3-60 nm, which is used as a support. The invention also relates to a method of using the catalyst to remove carbon monoxide from air, which is carried out using the catalyst by passing a stream of moist air containing up to 100-115 mg/m3 CO through the catalyst bed at room temperature.
EFFECT: improved catalyst properties.
4 cl, 1 tbl, 4 dwg, 5 ex
The invention relates to the field of heterogeneous catalysis, namely the low-temperature oxidation of CO (carbon monoxide, carbon monoxide), and can be used for cleaning air in enclosed spaces (for example, the interior of motor vehicles), industrial, office and residential spaces.
Catalytic oxidation of air pollutants (carbon monoxide, formaldehyde and other volatile organic compounds) to harmless CO2and water recently attracted special attention as an effective and promising method of air purification. Carbon monoxide is one of the most dangerous and widespread pollutants. It is produced from the combustion of various materials, forest fires, operation of internal combustion engines or in the untimely closure of the flue of the heating furnace. The maximum allowable concentration of CO in the air of working zone is not more than 20 mg/m3(GN 22.214.171.1243-03), and for premises of a valid daily average concentration is 3 mg/m3(GN 126.96.36.1998-03). The main difficulty of air purification from impurities CO is that CO catalytic oxidation must occur at room temperature and ambient humidity no less than 50%.
Most active in low-temperature CO oxidation are applied to�talesfore, containing as an active ingredient gold, palladium and platinum [RF №2506988 from 20.02.2014, RF 2339446 from 27.11.2008, RF 2464086 from 20.10.2012]. In the literature one can distinguish two main groups of catalysts. The first group consists of the catalytic composition constituting the noble metal deposited on an inert media, such as Al2O3[X. Zou, S. Qi et al. Activity and deactivation of Au/Al2O3catalyst for low temperature CO oxidation //Catalysis Communications. - 2007. - V. 8. - P. 784-788; A. Satsuma, K. Osaki, M. Yanagihara et al. Activity controlling factors for low-temperature oxidation of CO over supported Pd catalysts //Applied Catalysis B: Environmental. - 2013. - V. 132-133. - P. 511-518; K. Arnby, A. Törncrona et al. Investigation of Pt/γ-Al2O3catalysts with locally high Pt concentrations for oxidation of CO at low temperatures //Journal of Catalysis. - 2004. - V. 221. - No. 1. - P. 252-261] or SiO2[H. Zhu, Z. Ma, Jason C. Clark et al. Low-temperature CO oxidation on Au/fumed SiO2-based catalysts prepared from Au(en)2Cl3precursor //Applied Catalysis A: General. - 2007. - V. 326. - P. 89-99; J. L. Margitfalvi, I. Borbáth, M. Hegedűs. Low temperature oxidation of CO over a tin-modified Pt/SiO2catalysts //Catalysis Today. - 2002. - V. 73. - №3-4. - P. 343-353].
The second group is represented by catalysts, in which the media are oxides of transition metals, e.g., cerium oxide [A. Satsuma, K. Osaki, M. Yanagihara et al. Activity controlling factors for low-temperature oxidation of CO over supported Pd catalysts //Applied Catalysis B: Environmental. - 2013. - V. 132-133. - P. 511-518; X. Huang, H. Sun, L. Wang et al. Morphology effects of nanoscale ceria on the activity of Au/CeO2catalysts for low temperature CO oxidation //Applied Catalysis B: Environmental. - 2009. - . 90. - P. 224-232], iron [S. Kudo, T. Maki et al. A new preparation method of Au/ferric oxide catalyst for low temperature CO oxidation //Chemical Engineering Science. - 2010. - V. 65. - No. 1. - P. 214-219; L. Liu, F. Zhou, L. Wang et al. Low-temperature CO oxidation over supported Pt, Pd catalysts: the Particular role of FeOxsupport for oxygen supply during reactions //Journal of Catalysis. - 2010. - V. 274. - No. 1. - P. 1-10], manganese [Q. Ye, J. Zhao, F. Huo et al. Nanosized Au supported on three-dimensionally ordered mesoporous b-MnO2: Highly active catalysts for the low temperature oxidation of carbon monoxide, benzene, and toluene //Microporous and Mesoporous Materials. - 2013. - V. 172. - P. 20-29].
However, these catalytic systems are not sufficiently stable in the presence of CO2and water vapor. The cause of deactivation may be the adsorption of water, the formation of adsorbed carbonates and hydroxocobalamin, blocking the active sites of the catalyst surface. To increase the stability of the catalyst requires additional cleaning of the air, which complicates the design of the entire air-scrubbers. So, in [H. Zhu, Z. Ma, Jason C. Clark et al. Low-temperature CO oxidation on Au/fumed SiO2-based catalysts prepared from Au(en)2Cl3precursor //Applied Catalysis A: General. - 2007. - V. 326. - P. 89-99] used a dry mixture based on the air with the water vapor content less than 4 ppm. However, even in these conditions, the catalyst Au/SiO2were subjected to decontamination (after 20 hours, the conversion decreased from 85 to 70%). The authors other work [Y. Shen, G. Lu, Y. Guo. An excellent support of Pd-Fe-Oxcatalyst for low temperature CO oxidation: CeO2with rich (200) facets //Catalysis Communicaions. - 2012. - V. 18. - P. 26-31] a study was conducted on the stability of the catalyst Pd-FeOx/CEO2at 25°C. it is Established that when using a mixture of CO+air water vapor content less than 10 ppm, the catalyst begins to lose activity after 2 hours of work.
Because of these disadvantages and high cost of catalysts based on Au, Pd and Pt (even when they are sufficiently small content), more stable and cheap silver system could potentially be used in the systems of purification of air in enclosed spaces.
In the patent [EP 2191884 from 26.06.2013] described the catalyst Ag/Al2O3obtained by impregnation of boehmite aqueous solution of silver nitrate, followed by drying at 100°C, the annealing of catalyst at 900-1000°C in air and the recovery at 100-500°C in a stream of a mixture of 1% H2/He. However, this catalyst has no activity in CO oxidation at room temperature.
Known silver-containing catalyst, which is inert substrate used active oxide media such as CeO2[US 8360073 from 29.01.2013]. This catalyst was developed as an additive to cigarette filter to reduce the concentration of carbon monoxide in the inhaled smoke, but can potentially be used for air purification. However, the low-temperature activity of the catalyst �ri relatively low silver content (10 wt. % in terms of Ag2O) is not high enough. With increasing silver content to 40 wt. % (in terms of Ag2O) low-temperature activity increases, however, decreases significantly for several minutes. To return activity to the initial level requires heating of the catalyst layer 110aboutC. it Should also be noted that increasing the silver content in the catalyst is disadvantageous from an economic point of view.
The closest to the claimed technical essence is a CO oxidation catalyst based on silver nanoparticles stabilized in mesoporous silica gel described in [CN 101890349 from 24.11.2010] and selected as a prototype.
The catalyst containing 1-16 wt. % Ag/SiO2receive a one-step synthesis using silver nitrate (AgNO3) as a precursor of the silver particles, tetraethoxysilane (Si(OC2H5)4, TEOS) as a source of silicon, formaldehyde (HCHO) as a reductant and dodecylamine (C12H25NH2) as a template. The molar ratio of the reactants TEOS:C12H25NH2:C2H5OH:AgNO3:HCHO:H2O=1:0,2965:7,593:0,0055-0,088:0,131:24,58. After the completion of the recovery of silver and of gelation (24-48 h) the resulting product was washed with deionized water, dried p�and 80-120°C and calcined at 400-600°C. The catalytic properties of the catalyst (loading 200 mg) in the reaction of CO oxidation was evaluated by the degree of conversion of CO at various temperatures using a gas mixture containing 1%CO, 0.5 TO 20% O2, 98,5-79 He (volumetric feed rate of 30 ml/min). The catalyst provides 100% conversion of CO at 60°C for 12 hours of continuous operation.
A feature of the catalyst of the prototype is the high value of specific surface area (878-1142 m2/y) with a pore size of 2.2-2.8 nm. Materials with similar textural characteristics have low strength characteristics and are highly dispersed powders, poorly pressed or hard-molded to obtain pellets of a given size and shape [A. P. Karnaukhov Adsorption. The texture of dispersed and porous materials. Novosibirsk: Nauka, 1999. - 470 p.]. The catalyst in this form seems to be inconvenient for use in real systems cleaning air WITH.
Given that the pore size of the catalyst of the prototype is 2.2-2.8 nm is expected to have low stability of the catalyst in the presence of water vapor, i.e., in the humid air. Adsorption of water vapor with subsequent condensation in high humidity conditions will lead to blocking of the active surface (the inner part of the granule or block parts of the porous space) and decontamination catalysate�.
It is also important to note that the study of the activity and stability of the catalyst was carried out using a gas mixture of He/O2/CO, free from water vapor, so nothing is known about the activity of the catalyst of the prototype in the presence of water vapor and the change in the activity of the catalyst in continuous operation for more than 12 hours.
The technical problem to be solved by the present invention is to develop a catalyst with high efficiency oxidation of carbon monoxide to carbon dioxide (CO2, carbon dioxide) over a long period of time at temperatures close to ambient, atmospheric air containing water vapor (humidity not less than 50%).
To solve this problem we used a catalytic oxidation of carbon monoxide containing as an active ingredient silver (1-16 wt. % ) deposited on silicon dioxide (silica gel) with a specific surface area of 50-200 m2/g and a pore size of 3-60 nm, and can also contain oxides of cerium, zirconium, manganese or a mixture of these oxides in an amount up to 10% by weight of the catalyst.
We offer the silver-containing catalyst prepared by impregnation from an aqueous solution of silver nitrate (the most affordable and cheap precursor of the active component), followed by those�chemical treatment to (400-700)°C. The proposed method is easy to implement in laboratory conditions and can be used for industrial (semi) obtaining a catalyst.
The technical result according to the method of applying the catalyst is to increase the stability of the catalyst due to thermal pre-treatment media and additives oxide modifier, and also due to the uniformity of application and small size of the particles of the active ingredient is silver.
The problem is solved in that a method of using the catalyst for purification of air from carbon monoxide is carried out using a catalyst according to claims. 1-3 of the formula by passing the stream of humid air containing CO (up to 100-115 mg/m3), through the catalyst bed at room temperature.
As a carrier can be used silica gels of various grades, including those available on the Russian market technical silicagel XKG. The technical problem is solved due to the special conditions of pretreatment of the carrier, consisting of a hydrothermal treatment of silica gel in the presence of an aqueous solution of ammonia to modify the porous structure and providing additional strength to the pellets, followed by high temperature treatment at temperatures of 500-1000°C.
The catalyst has the form of spherical granules, the size of which op�Adelaide the size of grains of the original media. Also the catalyst may be obtained in the form of granules of different size and shape depending on the requirements of the air treatment device in which it will be used.
The essence of the invention is as follows.
The low-temperature oxidation catalyst WITH contains silver as an active ingredient in a number (1-16) % by weight of the catalyst, silicon dioxide as the carrier and may contain oxides of cerium, zirconium and manganese in an amount up to 10% by weight of the catalyst. The catalyst is characterized in that it has a mesoporous structure with a developed system of transport pores (3-60 nm), providing efficient transfer of reagents, including water vapor. The isotherms of adsorption-desorption of nitrogen and the distribution of pore size for the catalysts described in examples 1-3, are shown in Fig. 1 and Fig. 2, respectively. It is seen that for all samples the main distribution of pores is in the area of 15-40 nm.
Another feature of the catalyst is that the silver is in the form of particles smaller than 6 nm. Fig. 3 shows a PAM image as well as the distribution of the silver particles size of the catalyst described in example 2. It is seen that the silver is evenly distributed along the surface of the carrier, and the particle size of silver is 1-6 nm with an average particle size of 2.8 nm.
Clean air�ha from WITH carried out by passing a stream of moist air containing 100-115 mg/m3WITH, through the catalyst bed at temperatures close to room. Observed in this technical effect is to make more than 80% of CO in CO2and this conversion for a long time (at least 20 hours).
The proposed catalyst was obtained by the following method.
Pre-calcined at 500-900°C, the silica gel was impregnated with an aqueous solution containing a predetermined amount of silver nitrate or ammonia complex of silver nitrate, then the resulting samples were dried at 70°C without access of light during the day and calcined to 500°C in air. Catalysts containing the oxides of transition metals, obtained by impregnating silica gel with an aqueous solution of nitrates of the respective metals and silver nitrate followed by heat treatment under similar conditions.
The essence of the claimed invention is illustrated by the description, the drawings and table:
Fig. 1 shows the isotherms of adsorption-desorption of nitrogen for the catalysts described in examples 1-3;
Fig. 2 shows the distribution of pore size for the catalysts described in examples 1-3;
Fig. 3 shows the PAM image and the distribution of the silver particles size of the catalyst described in example 2;
Fig. 4 shows the dependence of the degree of conversion of CO from time to Cathal�congestion, the compositions described in examples 1-4;
Table 1 provides data on the porous structure of catalysts and a comparison of the CO oxidation process in real conditions, clean the air with humidity not less than 50% for the catalysts described in examples 1-4.
The efficiency of the catalyst characterized by the following values: degree of transformation WITH at 29°C, expressed in percent, the lifetime of the catalyst in a stream of air with a humidity of not less than 50%.
The present invention is illustrated by examples of specific performance.
Example 1. The catalyst composition of 8 wt. % Ag, SiO2- the rest.
Commercial silica gel brand XCG (GOST 3956-76, Sbeats=268 m2/g, Vthen=0,95 cm3/g, Dthen=10 nm) was used as a carrier. The silica gel was subjected to a hydrothermal treatment in an aqueous solution of ammonia at 120°C for 3 hours. Further, the silica gel was dried in air at 120°C for 3 h. the resulting carrier has a specific surface area of 98 m2/g. Silica gel (2,76 g) soaked in water holding capacity (water volume 2.0 ml) with an aqueous solution of silver nitrate (0,378 g), then the sample is dried at 70°C overnight, calcined in air atmosphere at 500°C.
Is characterized in that as the carrier used technical silicagel XCG (GOST 3956-76, Sbeats=28 m 2/g, Vthen=0,95 cm3/g, Dthen=10 nm), in the form of spherical granules with a diameter of 3-6 mm or in the form of granules of irregular shape smaller size.
Example 2. The catalyst composition of 8 wt. % Ag, SiO2- the rest.
Similar to example 1. The difference is that the silica gel used as the carrier was subjected to additional high-temperature treatment at 700°C before applying the active component.
Example 3. The catalyst composition of 8 wt. % Ag, 10% wt. MnOx(calculated as MnO2), SiO2- the rest. Similar to example 2, the difference lies in the fact that in its composition contains oxides of manganese in an amount of 10 wt%. in the calculation of MnO2.
Example 4. The catalyst composition of 8 wt. % Ag, 10 wt. % Ce0,5Zr0,5O2, SiO2- the rest.
Similar to example 2. The difference lies in the fact that in its composition contains the oxides of zirconium and cerium in an amount of 10 wt%.
Example 5. Method of air purification from WITH is passing moist air containing 100 to 115 ppm of CO, through the catalyst bed described in p. 1-4.
In table 1 and Fig. 4 shows the results of catalytic testing of the proposed catalysts in conditions close to real operating conditions of air-cleaning devices, as well as their comparison with catalyst-prototype (CN 101890349 from 24.11.2010). The air humidity not less than 50% contained�of ASI 100-115 ppm CO, was passed through the quartz reactor with a catalyst made of PP. 1-4 (volume of catalyst 0.5 cm3) at a flow rate of 100 ml/min at a temperature of 29°C. the Residual concentration was measured WITH an electrochemical sensor.
Analysis of the results of experimental determination of the efficiency of catalysts, the composition of which is listed in Table 1, in the cleaning process of moist air from impurities of carbon monoxide, showed that the catalysts provide efficient removal of 100-115 mg/m3CO (conversion not less than 80%) within an extended period of time (20 hours).
All described in the examples, the catalysts contain not more than 8.0 wt. % of silver, and a method of producing the present catalyst is more simple in comparison with the prototype.
The use of pre-calcination of silica gel and applying the composition of oxides of transition metals makes the catalyst more resistant to the adsorption of water vapor and CO2that allows to increase the activity and prolong its service life.
Thus, the above data confirm that the implementation of the use of the claimed invention, the following set:
- the claimed method and the catalyst is intended for use in catalytic purification of moist air from impurities of carbon monoxide;
- for the claimed invention in the form as it is characterized in the independent claims, confirmed the possibility of its implementation using the described in the application of tools and methods.
1. The catalyst of low-temperature oxidation of carbon monoxide, representing the silver deposited on the surface of silicon dioxide in amounts of 1 to 16% by weight of the catalyst, characterized in that it comprises silver nanoparticles with size<6 nm, which are uniformly distributed on the surface of mesoporous silica having a specific surface area of 50-200 m2/g and a pore size of 3-60 nm, used as a carrier.
2. The catalyst according to claim 1, characterized in that in its composition contains oxides of manganese in an amount up to 10 wt.% in the calculation of MnO2.
3. The catalyst according to claim 1, characterized in that in its composition contains the oxides of zirconium and cerium in an amount up to 10 wt.%.
4. A method of using the catalyst for purification of air from carbon monoxide, characterized in that it is carried out using a catalyst according to claims. 1-3 by passing the stream of humid air containing CO (up to 100-115 mg/m3), through the catalyst bed at room temperature.
SUBSTANCE: invention can be used in obtaining coatings, reducing coefficient of secondary electronic emission, growing diamond films and glasses, elements, absorbing solar radiation. Colloidal solution of nano-sized carbon is obtained by supply of organic liquid - ethanol, into chamber with electrodes, injection of inert gas into inter-electrode space, formation of high-temperature plasma channel in gas bubbles, containing vapours of organic liquid. High-temperature plasma channel has the following parameters: temperature of heavy particles 4000-5000K, temperature of electrons 1.0-1.5 eV, concentration of charged particles (2-3)·1017 cm3, diameter of plasma channel hundreds of microns. After that, fast cooling within several microseconds is performed.
EFFECT: simplicity, possibility to obtain nanoparticles of different types.
3 cl, 1 dwg
SUBSTANCE: invention relates to field of nanotechnologies and can be used for obtaining composite materials with high electric and heat conductivity, additives to concretes and ceramics, sorbents, catalysts. Carbon-containing material is evaporated in volume thermal plasma and condensed on target surface 9 and internal surface of collector 7. Plasma generator 3, which includes coaxially located electrodes: rod cathode 4 and nozzle-shaped output anode 5, are used. Gaseous carbon-containing material 6 is supplied with plasma-forming gas through vortex chamber with channels 2 and selected from the group, consisting of methane, propane, and butane. Bottom of collector is made with hole 8 for gas flow to pass.
EFFECT: invention makes it possible to reduce energy consumption of the process, extend types of applied hydrocarbon raw material, simplify device construction and provide continuity of the process and its high productivity.
2 dwg, 3 ex
SUBSTANCE: invention relates to synthesis of diamond nanoparticles, which can be used in various fields of technology. Claimed method of synthesis of ultradispersed diamonds includes generation of carbon plasma from carbon-containing substance and its condensation with cooling liquid under conditions of cavitation. As plasma-generating substance any hydrocarbon gas or organic carbon-containing liquid, including one which additionally contains substances, containing heteroatoms, as well as dispersions of carbon particles of non-diamond allotropic shape in organic fluids or water, can be used. Flow of liquid inside flow cavitation apparatus, providing additional cavitation impact on cooling liquid, is used as cooling liquid.
EFFECT: invention makes it possible to increase energy efficiency of realised synthesis of nanodiamonds and provides possibility of managing properties of synthesised nanodiamonds.
3 dwg, 1 tbl
SUBSTANCE: method of obtaining a composite material includes the influence on a mixture of a carbon-containing material, filler and sulphur-containing compound by a pressure of 0.1-20 GPa and a temperature of 600-2000°C. As the sulphur-containing compound applied is carbon bisulphide, a compound from the mercaptan group or a product of its interaction with elementary sulphur. As the carbon-containing material applied is molecular fullerene C60 or fullerene-containing soot. As the filler applied are carbon fibres, or diamond, or nitrides, or carbides, or borides, or oxides in the quantity from 1 to 99 wt % of the weight of the carbon-containing material.
EFFECT: obtained composite material can be applied for manufacturing products with the characteristic size of 1-100 cm and is characterised by high strength, low density, solidity not less than 10 GPa and high heat resistance in the air.
11 cl, 3 dwg, 11 ex
SUBSTANCE: preliminary devolatilisation and purification of a rolled film is realised in a mixture of an inert gas and nitrogen with its movement relative to plasma of a magnetron discharge in a vacuum chamber. The application of oxide is carried out in the chamber with, at least, one pair of magnets in the bipolar pack-pulse mode or their electrical power supply with the stabilised voltage and current, limit for the source of electricity.
EFFECT: creation of multilayer polymer films, high-barrier relative to the penetration of gases and vapours.
3 cl, 1 dwg, 1 ex
SUBSTANCE: invention relates to method of obtaining L-arginine nanocapsules in sodium alginate envelope. In the process of method realisation L-arginine is suspended in benzene. Obtained mixture is dispersed into suspension of sodium alginate in hexane in presence of preparation E472c with mixing at 1000 rev/sec. After that, chloroform is added, and obtained suspension of nanocapsules is filtered and dried at room temperature. Process is realised for 15 minutes.
EFFECT: method in accordance with invention provides simplification and acceleration of process of obtaining nanocapsules and increased output by weight.
SUBSTANCE: tray for high-temperature superconducting (HTS) powder is mounted coaxially to an arc evaporator. A rotated inductance coil and a metal perforated disc are installed on a flexible electroconductive shaft between the evaporator and the tray. The tray is equipped with vibration and mechanic stirrers for powder. The arc evaporator is equipped with a cathode and the inner surface of a vacuum chamber and the surface of the electroconductive equipment serves as an anode. The vacuum chamber is equipped with a reaction gas feed system.
EFFECT: improved quantum electromagnetic properties of nanosized crystals in coating particles for HTS powder.
2 cl, 1 dwg
SUBSTANCE: invention relates to a method of producing bismuth ferrite-based nanopowder for producing magnetoelectric materials - multiferroic materials and electronic components, which can be widely used in microelectronics, particularly spin electronics (spintronics), sensor and microwave engineering, information recording, reading and storage devices, etc. The objective of the present invention is to produce pure homogeneously dispersed nanocrystalline bismuth ferrite-based powder with strict stoichiometry in a single step for producing electronic materials and components. The advantages of the present method are: directly obtaining single-phase bismuth ferrite; purity and homogeneity; low synthesis temperature; rapidness owing to obtaining the product in a single synthesis step.
EFFECT: invention increases efficiency and reduces power consumption when producing pure homogeneously dispersed nanocrystalline bismuth ferrite-based powder with strict stoichiometry by heating, at different rates, a glycerine-containing solution of nitrates of corresponding metals with different saturation.
SUBSTANCE: method includes crushing and fractioning of initial raw material, delignification of initial raw material, which includes alkaline hydrolysis with further washings, two-stage acidic hydrolysis with intermediate neutralisation and three washings, bleaching with three washings with ozonation, with possible additional stages of homogenisation and drying.
EFFECT: invention makes it possible to obtain final product, possessing high absorbing and adsorbing properties, high water retention coefficient.
SUBSTANCE: invention relates to production of glucosamine sulphate nanocapsules in a konjac gum shell. According to the present method, glucosamine sulphate is added in portions to a suspension of a konjac gum in butyl alcohol containing an E472c preparation as a surfactant. The weight ratio of glucosamine sulphate and konjac gum is 1:3. The mixture is stirred. Hexane is then added and the obtained nanocapsule suspension is filtered, washed with hexane and dried. The process is carried out at 25°C for 15 minutes.
EFFECT: method simplifies and speeds up the process of producing nanocapsules in konjac gum and increases mass output.
1 tbl, 2 ex, 1 dwg
SUBSTANCE: invention relates to a process of formaldehyde removal by catalytic oxidizing which can be used in waste water treatment in petrochemical, medical, chemical and pharmaceutical industries. The process of formaldehyde removal from aqueous solutions at ambient temperature comprises exposing formaldehyde to a catalyst and oxidizing with oxygen. A nanocomposite material comprising silver - high basic anion exchanger in OH--form is used as a catalyst. The oxidation is conducted within 0.5-5 hours.
EFFECT: simple and cost-effective method for removal of up to 60-80% of the initial formaldehyde concentration in aqueous solutions at the temperature of T = 20-25°C and atmospheric pressure.
SUBSTANCE: disclosed is a catalyst containing nanoparticles of a noble metal on a support - mesoporous zeolite-like silicate MCM-41. The noble metal used in the catalyst is nanoparticles of silver metal with size of 2-5 nm, with the following ratio of components, wt %: Ag - 0.5-10, support - the balance. Also disclosed is a method for hydroamination of liquid acetylene hydrocarbons with an amine at 100-150°C in the presence of a silver-containing catalyst Ag/MCM-41, molar ratio of the amine to the acetylene hydrocarbon of 1-1.5:1, and molar ratio of the acetylene hydrocarbon to the silver in the catalyst of 210-1000:1. The amine used is aniline or piperidine.
EFFECT: faster hydroamination as a result of using the disclosed catalyst and high efficiency of the process while maintaining a high degree of conversion of acetylene hydrocarbons.
3 cl, 1 tbl, 5 ex
SUBSTANCE: invention relates to a catalyst system for reducing nitrogen oxides from exhaust gases containing at least two catalyst layers, wherein the first catalyst layer is an iron-beta-zeolite, and the second catalyst layer lying downstream, is silver which is deposited on aluminium oxide, as well as use of said catalyst system to treat exhaust gases from internal combustion engines operating on diluted mixtures, gas turbines and evaporators. The invention also relates to a method of reducing nitrogen oxides to nitrogen in exhaust gas, which includes passing exhaust gas in the presence of a reducing agent through a catalyst system containing at least two catalyst layers, wherein the first catalyst layer is an iron-beta-zeolite and the second catalyst layer, lying downstream, is silver deposited on aluminium oxide.
EFFECT: improved technological capabilities of removing NOx from exhaust gases.
14 cl, 8 dwg, 3 ex
SUBSTANCE: invention relates to field of catalyst. Described is method of obtaining silver crystals with distribution of average size of particles from 0.15 mm to 2.5 mm and porous coating of oxide materials in which a) silver crystals contact with sol-gel solution of said materials, in solvent, which contains organic solvent and b) obtained as a result silver crystals are collected, c) released from organic solvent and d) then subjected to thermal processing at temperature between 50°C and point of silver melting. Described is application of obtained crystals as catalyst for obtaining formaldehyde.
EFFECT: increased activity of catalyst for obtaining formaldehyde.
10 cl, 3 dwg, 4 tbl, 1 ex
SUBSTANCE: invention relates to catalyst supports and catalysis. Described is a support for an ethylene epoxidation catalyst which contains aluminium oxide coupled with a stability enhancing amount of mullite, said stability enhancing amount of mullite being about 7-20% mullite. Described is an ethylene epoxidation catalyst which contains said support and use thereof in a method of converting ethylene to ethylene oxide in vapour phase in the presence of oxygen.
EFFECT: high stability of ethylene epoxidation catalyst.
31 cl, 1 dwg, 2 tbl, 2 ex
SUBSTANCE: invention relates to carriers for catalytic systems and their application. Carrier for catalytic system, which contains at least one catalytically active metal, placed on it, which includes having definite geometric form refractory solid carrier from aluminium oxide (Al2O3), in which width of at least one wall of said having definite geometric form refractory solid carrier from aluminium oxide (Al2O3) constitutes less than 2.5 mm. Catalyst, which includes said carrier and its application at olefin epoxidation are described.
EFFECT: increased efficiency and selectivity of catalyst.
24 cl, 1 tbl, 1 ex
SUBSTANCE: invention relates to catalysts. Described is a catalytic block based on nickel foam and alloys thereof for purifying gases from organic compounds, including benzopyrenes, dioxins, nitrogen oxides, ammonia, carbon and ozone in form of a block which consists of an assembly of separate plates made from nickel foam and alloys thereof with a coating, placed in a cassette made from stainless steel at distance from each other, wherein a support, which is in form of plates made from nickel foam and alloys thereof, which are coated with a heat-resistant coating, is placed at an angle 30-90° to the direction of the gas flow, wherein the support has the following composition, wt %: aluminium oxide 4-55 or titanium oxide - 0.5-10; lanthanum oxide - 0.5-5.0; manganese oxide - 0.25-2.5; silver - 0.1-0.2; nickel foam and alloys thereof - the balance.
EFFECT: wider range of purification catalysts.
1 dwg, 1 tbl, 5 ex
SUBSTANCE: invention relates to field of heterogenic catalysis, namely to catalyst for purification of exhaust industrial gases from volatile organic compounds, and can be used in chemical industry, for instance, for complete oxidation of exhaust gases of glyoxal production from admixtures of formaldehyde, ethylene glycol, carbon monoxide. Described is catalyst for purification of exhaust gases from volatile organic compounds, including cerium dioxide, manganese oxide, silver and carrier - mesoporous silica gel. Also described is method of obtaining catalyst, which includes impregnation of mesoporous silica gel with water solution containing manganese and cerium nitrates, then, after intermediate drying and thermal processing impregnation with ammonia solution of silver oxide with further final drying and thermal processing. Described is method of purification of exhaust gases, which contain volatile organic compounds, with application of said catalyst.
EFFECT: increased catalyst efficiency due to more uniform active silver component on carrier surface, elaboration of shorter method of obtaining catalyst for purification of exhaust gases, containing volatile organic compounds.
12 cl, 3 tbl, 4 ex
SUBSTANCE: invention relates to field of heterogenic catalysis, in particular, to method of obtaining catalyst for isotopic protium-deuterium exchange. Method includes obtaining metal nanoparticles in reduction of metal ions in inverse micellar solution, consisting of solution of metal salt, representing RhCl3 or RuOHCl3, SAS, representing sodium bis(2-ethylhexyl)sulfosuccinate, and non-polar solvent, isooctane, with further application on Al2O3 carrier, with silver nanoparticles being obtained by preparation of inverse micellar rhodium or ruthenium solutions with ratio of molar quantity of metal salt water solution to molar quantity of SAS in the range from 1:1 to 10:1; after that water-alcohol solution in quantity 5-50 wt % and ammonium solution in quantity 10-30 wt % are added, after which suspension is subjected to ultrasound processing, deaeration and exposure to γ-irradiation 60Co with dose from 1 to 40 kGy.
EFFECT: invention makes it possible to obtain catalyst which possesses high catalytic activity and is intended for work in temperature interval 77÷400 K.
2 cl, 4 tbl, 4 ex
SUBSTANCE: invention relates to a method of filling a longitudinal section of a contact pipe with a homogeneous part of a solid catalyst bed. The method of filling a longitudinal section of a contact pipe with a homogeneous part of a solid catalyst bed, the active mass of which is at least one multielement oxide which contains a) elements Mo, Fe and Bi, or, b) elements Mo and V, or c) element V, and additionally P and/or Sb, or the active mass of which contains elementary silver on an oxide support-article, and which consists of only one type Si, or a homogenised mixture of various types Si of catalytically active moulded articles of a defined geometrical shape or catalytically active moulded articles and inert moulded articles of a defined geometrical shape, wherein the median of the maximum longitudinal dimensions Ls i of the articles of a defined geometrical shape of type Si is characterised by the value Ds i, at least within one type Si of moulded articles of a defined geometrical shape, the following set of conditions M is satisfied, such that 40 to 70% of the total number of moulded articles of a defined geometrical shape belonging to S1, have a maximum longitudinal dimension Ls i, for which the inequality 0.98·Ds i≤Ls i≤1.02·DS i holds, at least 10% of the total number of moulded articles of a defined geometrical shape belonging to Si have a maximum longitudinal dimension Ls i, for which the inequality 0.94·Ds i≤Ls i<0.98·Ds i holds, at least 10% of the total number of moulded articles of a defined geometrical shape belonging to S1 have a maximum longitudinal dimension Ls i for which the inequality 1.02·Ds i<Ls i≤1.10·Ds i holds, less than 5% of the total number of moulded articles of a defined geometrical shape belonging to Si have a maximum longitudinal dimension Ls i for which the inequality 0.94·Ds i>Ls i holds, and less than 5% of the total number of moulded articles of a defined geometrical shape belonging to Si have a maximum longitudinal dimension Ls i for which the inequality 1.10·Ds i<Ls i holds, wherein the sum of all moulded articles of a defined geometrical shape belonging to Si is 100%; described also is a method of loading a contact pipe with a solid catalyst bed, a shell-and-tube reactor, a method for oxidation of an organic compound and a method for synthesis of separate organic compounds.
EFFECT: high selectivity of moulding the final synthesis product.
17 cl, 3 ex
SUBSTANCE: catalyst is characterised by the following content of components: 30-70 wt % (Mo5-12Sb>6.0-15Bi0.2-3M1 0.1-10M2 0.05-0.5M3 0.01-2On) and 70-30 wt % SiO2, where M1 is one or more elements selected from Co, Ni, Fe, Cr, Cu; M2 is one or more elements selected from Na, K, Cs, Mg, Ce, La, M3 is an element selected from P, B, n is a number defined by the valence and number of elements other than oxygen. The invention also relates to a method of producing butadiene-1,3 using said catalyst.
EFFECT: catalyst enables to achieve high butadiene selectivity in oxidative dehydrogenation of n-butenes and provides high output of butadiene.
3 cl, 1 tbl, 7 ex