The carrier and the catalyst for heterogeneous reactions

 

(57) Abstract:

The invention relates to catalysts used in deep oxidation of hydrocarbons (afterburning of exhaust gases), partial oxidation of hydrocarbons (epoxidation of ethylene, propylene), alkylation of hydrocarbons, oxidation of sulfur dioxide in sulfuric acid production), hydrogenation (acetylene, nitrobenzene), the conversion of ammonia (nitrogen and hydrogen cyanide) and the other Describes the carrier of the catalyst for heterogeneous reactions, for example for deep oxidation of hydrocarbons, partial oxidation of hydrocarbons, alkylation of hydrocarbons, oxidation of sulfur dioxide, hydrogenation of hydrocarbons, ammonia conversion and others, including oxides of silicon and/or aluminum, the media contains centers, activating the applied catalytic substances, characterized in infrared absorption band of hydroxyl groups with wave number 3620-3650 cm-1and the width of 65-75 cm-1. The technical result is the development of active and stable in different processes, catalysts having a high strength by using certain media. 2 S. and 9 C.p. f-crystals, 1 Il., 6 table.

Their exhaust gases), partial oxidation of hydrocarbons (epoxidation of ethylene, propylene), alkylation of hydrocarbons, oxidation of sulfur dioxide in sulfuric acid production), hydrogenation (acetylene, nitrobenzene), the conversion of ammonia (nitrogen and hydrogen cyanide) and other

Usually the active components of catalysts for these processes represent the metals, their oxides or salts deposited on the media - amorphous or crystalline oxides of silicon and/or aluminium, magnesium, titanium, zirconium, etc., the Role of media is to provide the necessary thermal and mechanical properties of the catalyst (thermal stability, strength, durability, low hydraulic resistance), as well as in the implementation of the most active state damage catalytic components. The latter is usually achieved through the effects of media on the structure and chemical properties of the active metal complexes, dispersion and optimal distribution of the active particles in the media. One of the activation methods applied components is the use of highly dispersed, and therefore porous media.

A known catalyst (A. C. USSR N 1447393, MKI IN 123/26, 1988) for the purification of gases 2/g and a pore volume of 0.34 - 0,46 cm3/year In the composition of the catalyst comprises oxides of Nickel, chromium.

The disadvantage of the catalyst is low strength and stability, as well as the low degree of use of the applied active substances, due to the fact that the essential part is in deep pores of the pellet carrier and is not involved in the process of chemical transformation.

To improve stability, strength and hydrodynamic properties, it is preferable to have a more coarse media. To improve their ability to activate the applied catalytic substances in some cases on a coarse frame put an extra layer of fine media, and only after that enter the catalytically active substance.

Known ceramic coating for carriers of catalysts (US Patent N 5114901, MCI IN 1 J 21/08, 32/00), in which the frame of the carrier is applied to the dispersion of fine particles of silica, using particles of two sizes, so that particles of the same size filled the voids between the particles of different size.

The disadvantage of the catalysts prepared in this medium is not high enough activity.the comfort of chemical modification of the media. For example, in a known catalyst for chemical processes (Patent RF N 2069584, MCI IN 1 J23/38, 23/70, 1996) the composition of the catalyst carrier made in the form of granules, filaments, fibers, in the form of woven and nonwoven materials from oxides of silicon and/or aluminum, impose additional alloying of catalytically active metals and/or their oxides.

The catalyst compared with the previous analogues sufficiently solves the problem of increasing the service life of the catalysts, but the downside of it is the necessity of introducing a promoter at the stage of preparation of the medium with the subsequent stage of deposition of the active component, which leads to additional waste metals, especially precious metals.

In the field of catalysts, the composition of the medium composition and the method of introduction of the catalytically active components closest to the proposed invention is the Application of Japan N 63-34781, MCI IN 1 J 21/06. Catalyst for oxidation of carbon monoxide, hydrocarbons, degreasing and deodorizing processes, based on the decomposition of hydrocarbons, is a Foundation with a layer of the carrier with a coating of a catalytically active component. The base material contains 70% a is a crystalline mixture of 2 compounds, for example, oxides of aluminum, silicon, zirconium and titanium, as catalytically active components used noble metals such as platinum, palladium, rhodium or osmium, and the oxides of vanadium, iron, Nickel, manganese, cobalt, copper or chromium. The increased activity of the marked components is achieved through the use of highly dispersed amorphous or crystalline silicon - and aluminium-containing media in which to create additional activating centers enter a small amount of cerium.

The disadvantage of the catalyst is low strength and activity.

The problem solved by the present invention is the development of active and stable in different processes, catalysts having a high strength by using certain media.

The problem is solved when the media is used for the preparation of catalysts for heterogeneous reactions, for example, deep oxidation of hydrocarbons, partial oxidation of hydrocarbons, alkylation of hydrocarbons, oxidation of sulfur dioxide, hydrogenation of hydrocarbons, the conversion of ammonia, comprising the oxides of silicon and/or aluminum, the media contains centers, aka hydroxyl groups with wave number 3620-3650 cm-1and the width of 65-75 cm-1.

The media contains silicon dioxide 55-99 wt.% and has a specific surface area of 0.1 to 30 m2/, Content of hydroxyl groups in the matrix of the carrier (s-O-H) is in the range from two hydroxyl groups on one atom of silicon to one hydroxyl troupe on two atoms of silicon.

The carrier has the form of granules of spherical or irregularly shaped or has the form of filaments, fibers, woven or nonwoven materials.

The task is also solved using the proposed catalyst for heterogeneous processes, for example, oxidation of hydrocarbons, partial oxidation of hydrocarbons, alkylation of hydrocarbons, oxidation of sulfur dioxide, hydrogenation of hydrocarbons, the conversion of ammonia containing at least one active component selected from the group comprising platinum, palladium, rhodium, iridium, silver, zirconium, chromium, cobalt, Nickel, manganese, copper and/or their oxides in an amount not less than 0.01% on the media, including oxides of silicon and/or aluminum; media contains the centers that activates the applied catalytic substances, characterized in infrared absorption band of hydroxyl groups with the wave number of the LASS="ptx2">

The content of hydroxyl groups (- O-H) in the matrix carrier is in the range from two hydroxyl groups on one atom of silicon to one hydroxyl group on two atoms of silicon.

The magnitude of the carrier surface is 0.1-30 m2,

The carrier has the form of granules of spherical or irregular shape and/or form of filaments, fibers, woven or nonwoven materials.

The active component is deposited by impregnation on capacity media solutions of inorganic or organic compounds of the respective elements.

Our invention is a method of creation and nature activating centers, namely activating centers in the infrared spectrum, the characteristic absorption band of hydroxyl groups. High activating effect of these centers allows you to get active and stable catalysts as highly dispersed media, and relatively coarse media, the use of which is preferred due to better strength and hydrodynamic characteristics of the catalyst, but also due to better use, and therefore less catalytically active substances.

The detection is aderrasi oxides of silicon and/or aluminum. These centers are characterized by the high-frequency region of the IR spectra of the absorption band of hydroxyl groups with wave number 3620-3650 cm-1and the width of 65-75 cm-1. Note that we know of silica and silicates with a low specific surface ( 30 m2) the specific absorption band is not observed. For fine specimens of the most high-frequency is a band at 1740 10 cm-1. The drawing shows the IR spectra of several well-known silicon-containing samples.

Sample 1 (carrier prototype) - mixed oxide carrier containing 95 wt.% SiO2and 5 wt.% Al2O3(SID200 m2/g, Rthen40-300 A).

Sample 2 - industrial silica gel brand stewards, calcined at 1000oC (SID1.2 m2/g, Rthen7-10 104A).

In the IR spectra of these samples is observed broad absorption band with wave numbers in the interval 3400-3600 cm-1(drawing crooked. 1,2). In contrast, our invention the carriers have the absorption band with the wave number 3620-3650 cm-1and a width of 70 cm-1(drawing crooked. 3,4), which is most of the observed high-frequency.

mi. Let us point out some important principles of their receipt. We found that the above centers are formed during the extraction of amorphous or glassy silicon, aluminium-containing materials related cations subject to the following conditions:

a) homogeneous distribution of competing cations in the volume of silicon-containing source material;

b) lack of coalescence centers when removing cations and/or subsequent chemical and thermal treatments.

These conditions can be implemented, for example, as follows. Superfine powder Aerosil (SID150 m2/g, D grains 2-4 μm) is mixed with 1.5 wt.% NaOH, moisturize, homogenize, granularit in grain to the size of 3-4 mm, dried at a temperature of 110oC, calcined in air at 1200oC for 24 hours and treated with 20% solution of H2SO4at a temperature of 40oC for 2 hours. Obtained by this method, the sample 3 has a specific surface area measured by the BET method 1.3 m2/year In the IR spectrum is observed absorption band with wave number 3650 cm-1and a width of 75 cm-1(drawing, curve 3).

As starting materials for the production of offer is aloknath, woven and nonwoven products. Specific activating centers appear in the case, if the composition of the starting material and the conditions of its subsequent chemical and thermal treatments ensure the implementation of these principles is the emergence and persistence of active centers. So, in the drawing, crooked. a 4.5 shows the spectra of samples 4 and 5, obtained from the same source material (industrial glass), but distinguished by the preparation conditions. In the spectrum of sample 4 is band 3640 cm-1and a width of 70 cm-1, while the IR spectrum of sample 5 obtained in sub-optimal conditions, the intensity of this band decreases dramatically. Note that this is accompanied by a decrease in catalytic activity caused the catalytic substances (example 15).

The proposed media must contain silica and/or alumina, with preferably the content of SiO2not less than 55 wt.%.

The value of specific surface area of the proposed carriers, as measured by the BET method by adsorption of argon or nitrogen must be 0.1-30 m2/g, preferably 0.5 to 10 m2/, Advantage of using media such textural parameters is reduced or at a variety of shapes and sizes, optimal in specific catalytic processes: non-porous granules are spherical or irregular shape, filaments, fibers, woven or nonwoven materials.

As the applied active compounds is proposed to use metals (platinum, palladium, rhodium, iridium, silver, zirconium, chromium, cobalt, Nickel, manganese, copper) and/or their oxides in an amount not less than 0.01%. Such catalysts can be used for a wide range of catalytic processes, for example: deep oxidation of hydrocarbons, partial oxidation of hydrocarbons, alkylation, oxidation of sulfur dioxide, hydrogenation, the conversion of ammonia and other,

Thus, the proposed solution is new. Salient features of the carrier and catalyst are:

the carrier contains centers, activating the applied catalytic substance;

the centers feature in the infrared spectrum absorption band of hydroxyl groups with wave number 3620-3650 cm-1and the width of 65-75 cm-1.

The proposed catalysts prepared as follows:

Media in the form of granules, fibrous woven and nonwoven materials containing a specific band in the infrared spectrum (drawing, the next heat treatment.

As the palladium compounds preferably used salts of mineral acids, complex ammonium salts, salts of carboxylic acids. As platinum compounds using hexachloroplatinic acid, daugherity platinum tetrachloride hydrate, platinum, etc.

The catalysts of the prototype and obtained by the present method are experiencing in the process of deep oxidation in oxygen excess on model mixtures containing n-butane, propane and carbon monoxide.

Test for n-butane and carbon monoxide is performed on a flow-circulation installation at atmospheric pressure, the same space velocity of the gas mixture and the same test conditions.

For measure the catalytic activity of the catalyst in the oxidation of n-butane adopted responsiveness ((cm3C4H10)/ ,S. 10-2) oxidation of n-butane at a temperature of 400oC. the higher the speed of reaction of complete oxidation of butane corresponds to a more active catalyst.

For measure the catalytic activity of the catalyst in the oxidation of carbon monoxide adopted the temperature at which achieved 85% degree of oxidation of carbon monoxide.P CLASS="ptx2">

Tests on propane is carried out in an isothermal flow reactor. For measure of catalytic activity adopted value of the degree of conversion at a given temperature.

The catalysts have also in the oxidation of ammonia to oxides of nitrogen, NOx reduction by methane, epoxydecane olefins in the alkylation reaction of isobutane with butylene.

Data on the composition of the catalysts are given in table. 1.

The results are given in table. 2-6.

The following examples illustrate the invention.

Example 1. For the preparation of the catalyst containing 0.01 wt.% Pb, take pellets carrier comprising 96% of SiO2and having a diameter of 2-4 μm, SIDis 1.3 m2/year In the IR spectrum of this medium is characterized by the absorption band of Oh groups with the wave number 3645 cm-1and a width of 65 cm-1(drawing crooked.3).

Dissolve in water at room temperature estimated number of palladium nitrate. The concentration of the prepared impregnating solution is determined by the water capacity of the media and content of active ingredients in the finished catalyst.

Example 2. Similar to example 1, Astara hexachloroplatinic acid, and the medium consists of 80% SiO2and 20% Al2O3and has the form of a woven fibrous material. The IR spectrum of media there is an absorption band of Oh groups with the wave number 3640 cm-1and a width of 75 cm-1.

Example 3. The catalyst is similar to example 2, only different content components and the specific surface of the carrier.

Example 4. The catalyst is similar to example 2, only different content components and the specific surface of the carrier, as the active component contains palladium.

Example 5. The catalyst is similar to example 2, only as an active ingredient contains Nickel and cobalt, and the carrier has the form of fibers.

Example 6. The catalyst is the same as example 1, except that as the active component contains manganese and different content components.

Example 7. The catalyst is similar to example 2, only as an active ingredient contains copper and chrome.

Example 8. The catalyst is similar to example 2, only as an active ingredient contains silver and different content components.

Example 9. The catalyst is similar to example 8, only different content compit zirconium and different content components.

Example 11. The catalyst is similar to example 10, only different content components.

Example 12. The catalyst is similar to example 2, the content of hydroxyl groups (- O-H) in the matrix media is two hydroxyl groups on one atom of silicon, and the catalyst further comprises rhodium.

Example 13. The catalyst is similar to example 2, the content of hydroxyl groups (- O-H) in the matrix medium comprises one hydroxyl group on two silicon atom, as an active ingredient contains palladium and different content components.

Example 14 (comparison). For the preparation of the catalyst used non-porous silica (curve 2, the drawing), which is not typical for the declared object of the bands in the IR spectrum, the catalyst is prepared analogously to example 13.

Example 15 (for comparison). For the preparation of the catalyst used fiberglass cloth (curve 5), in which the characteristic band is absent, the catalyst is prepared analogously to example 13.

Example 16 (the prototype). For the preparation of the catalyst used is a mixed oxide containing 95 wt.% SiO2and 5 wt.% Al2O with SID200 m2/g, Rthen40-300 A (the Khabibullina impregnated with a solution of palladium chloride, dried, calcined.

Thus, from these examples it follows that the present invention is a carrier and a catalyst for heterogeneous reactions has unique physical and chemical properties. This allows to achieve high efficiency and selectivity of catalytic processes, the catalysts are characterized by high chemical and thermal stability, strength characteristics.

1. The carrier of the catalyst for heterogeneous reactions, for example for deep oxidation of hydrocarbons, partial oxidation of hydrocarbons, alkylation of hydrocarbons, oxidation of sulfur dioxide, hydrogenation of hydrocarbons, the conversion of ammonia, comprising the oxides of silicon and/or aluminum, characterized in that the medium contains centers, activating the applied catalytic substances, characterized in infrared absorption band of hydroxyl groups with wave number 3620 - 3650 cm-1and the half-width 65 - 75 cm-1.

2. Media under item 1, characterized in that the silicon dioxide content is 55 to 99 wt.%.

3. Media under item 1, characterized in that it has a specific surface area of 0.1 to 30 m2/,

4. Media under item 1, characterized in that one silicon atom of one hydroxyl group on two atoms of silicon.

5. Media under item 1, characterized in that it has the form of granules of spherical or irregularly shaped or has the form of filaments, fibers, woven and nonwoven materials.

6. The catalyst for heterogeneous reactions, for example for deep oxidation of hydrocarbons, partial oxidation of hydrocarbons, alkylation of hydrocarbons, oxidation of sulfur dioxide, hydrogenation of hydrocarbons, the conversion of ammonia containing at least one active component selected from the group comprising a plate, palladium, rhodium, iridium, silver, zirconium, chromium, cobalt, Nickel, manganese, copper and/or their oxides in an amount not less than 0.01% on the media, including oxides of silicon and/or aluminum, characterized in that the medium contains centers, activating the applied catalytic substances, characterized in infrared absorption band of hydroxyl groups with wave number 3620 - 3650 cm-1and the half-width 65 - 75 cm-1.

7. The catalyst p. 6, characterized in that the silicon dioxide content is 55 to 99 wt.%.

8. The catalyst PP.6 and 7, characterized in that the content of hydroxyl groups (- O-H) in the matrix carrier is in the range from two hydroxyl groups on one atom Creo value of the carrier surface is 0.1 - 30 m2/,

10. The catalyst p. 6, characterized in that the carrier has the form of granules of spherical or irregularly shaped or has the form of filaments, fibers, woven or nonwoven materials.

11. The catalyst p. 6, characterized in that the active component is deposited by impregnation on capacity media solutions of inorganic or organic compounds of the respective elements.

 

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