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INVENTION
Patent of the Russian Federation RU2282496

A METHOD FOR PREPARING A MEDICAL CALCULUME CATALYST (VARIANTS)

The name of the inventor: Komova Zoya Vladimirovna (RU); Firsov Oleg Petrovich (RU); Weinbender Alexander Yakovlevich (RU); Sharkina Valentina Ivanovna (RU)
The name of the patent owner: ALVIGO-M, Limited Liability Company (RU)
Address for correspondence: 111123, Moscow, sh. Enthusiasts, 38, LLC "ALVIGO-M", V.F. Dovganiucu
Date of commencement of the patent:

The invention relates to the production of copper-zinc-aluminum catalysts, which are used for low-temperature conversion of carbon monoxide by steam, for low-temperature methanol synthesis, for hydrogenation and dehydrogenation of various organic compounds. A method for the preparation of a catalyst comprising the preparation of ammonium carbonate solutions of copper and zinc, the treatment of an aluminum-containing feedstock with an ammonia-carbonate zinc solution, mixing of the treated or a mixture thereof with an untreated aluminum-containing feedstock and copper and zinc compounds, maintaining the resulting slurry in the reactor at elevated temperature and stirring, Separation of the resulting catalyst mass from the solution, drying, calcining and granulation, the treatment of the aluminum-containing raw material with an ammonia-carbonate zinc solution is carried out at a temperature of 75-90 ° C and kept under stirring until the decomposition of the ammonia-carbonate zinc solution, and the mixing of copper, zinc compounds And the aluminum-containing raw material is carried out in a dosed manner while maintaining the temperature in the reactor at 75-90 ° C and a predetermined ratio of copper to zinc in the liquid phase of the suspension, the zinc compounds being introduced into the reactor as an ammonia-carbonate solution or oxide or basic carbonate, In the form of an ammonia-carbonate solution, and the atomic ratio of copper to zinc in the resulting catalyst is (0.55-2.2): 1 at an atomic aluminum content of 2.6 to 10.6. The technical result is the creation of a simple and economical technology for the preparation of copper-zinc-aluminum catalysts, which do not have harmful wastewater and gas emissions and ensures the production of highly active, stable and mechanically strong catalysts.

DESCRIPTION OF THE INVENTION

The present invention relates to the production of copper-zinc-aluminum catalysts, which are used for low-temperature conversion of carbon monoxide by steam, for the low-temperature synthesis of methanol, for the hydrogenation and dehydrogenation of various organic compounds, for example, for the dehydrogenation of cyclohexanol to cyclohexanone in the production of caprolactam, for purifying gases from sulfur impurities, Carbon monoxide, oxygen, etc.

A method for the preparation of a copper -aluminum catalyst is known , comprising the preparation of a solution of nitric acid aluminum by dissolving its hydroxide in a solution of nitric acid, in excess of it against stoichiometry, dissolving zinc oxide in excess nitric acid contained in a solution of nitric acid, By dissolving metallic copper in a solution of nitric acid, by feeding the formed nitric gases into an absorber for absorption, obtaining a working solution by mixing in appropriate amounts of prepared solutions of nitric acid salts of copper, zinc, aluminum, preparing the precipitating agent - sodium carbonate solution by dissolving the solid salt in Water, precipitation (one or two-stage) of insoluble compounds of copper, zinc, aluminum at a given temperature and pH, by simultaneous or stepwise infusion of a mixed nitric acid solution of copper, zinc, aluminum and sodium carbonate solution into the precipitating reactor. The precipitated catalyst mass is stirred, cooled to 40-45 ° C, filtered from the mother liquor and washed on the filter with water at a temperature of 40-45 ° C until no sodium nitrate is present in the wash water. The mother liquor and washings are sent for purification and the washed catalyst mass is dried at 150 ° C. and then calcined at a temperature of 280-400 ° C. to a carbonate ion content of not more than 7% by weight (per CO ₂ ). The calcined mass is tabletted.

In this process, a catalyst is prepared for the low temperature synthesis of methanol. (Declaration patent of Ukraine No. 51460, B 01 J 37/03, 23/80, 2002).

A disadvantage of the known method is the formation of a large amount of washing water contaminated with sodium nitrate and requiring special purification, as well as the need for careful maintenance of the preset regime during the precipitation process, especially the pH in a narrow range (6.5-6.9). As a result, the properties of the precipitated mass and, accordingly, the finished catalyst are not reproducible. Nitric acid, used for the preparation of nitric acid solutions, has a strong chemical aggressiveness, and when dissolved in metallic copper, nitrogen oxides are released, which need to be disposed of.

It is also known to prepare a copper-zinc- aluminum catalyst for the synthesis of methanol by thermal decomposition of ammonium-carbonate copper and zinc complexes at a temperature of 60-100 ° C in the presence of aluminum hydroxide. This method involves the preparation of ammonium carbonate solutions of copper and zinc, mixing of the solutions prepared and the introduction of hydrated, gelatinous alumina-Al ₂ O ₃ · H ₂ O into the resulting mixture, holding the resulting suspension at a temperature of 75.5-99 ° C until decomposition of ammonia Carbonate complexes of copper and zinc to form the main carbonates, separating the catalyst mass on the filter and calcining it at 280 ° C, pressing the calcined powder into tablets (US Patent No. 4279781, 502-343, 1981).

This method of preparation differs from the comparative simplicity presented above and the absence of harmful emissions, but has a number of disadvantages.

Thus, the joint decomposition of ammonium-carbonate complexes of copper and zinc from a mixed solution does not ensure their quite complete coprecipitation and the production of a catalyst mass homogeneous in terms of the crystal-chemical composition: the rate of decomposition of the zinc complex is 3-4 times higher than that of the copper complex.

The method of preparation of a copper-zinc- aluminum catalyst , which includes the preparation of ammonium-carbonate solutions of copper and zinc, mixing solutions of ammonium-carbonate complexes of copper and zinc, treatment of aluminum hydroxide with an ammonia-carbonate zinc solution, mixing of an ammonium-carbonate solution of copper and Zinc with a suspension of freshly precipitated aluminum hydroxide, untreated or treated with an ammoniacal carbonate solution of zinc or a mixture thereof to form a suspended reaction mixture, feeding the reaction mixture in a continuous manner to a reactor containing a liquid medium constituting an ammoniacal carbonate solution of copper and zinc, while maintaining In the reactor a temperature of 84-96 ° C with continuous bubbling of CO ₂ and maintaining the total concentration of copper and zinc at a level of 100-120 g / l.

The suspended catalyst pulp is partially pumped to the filter and the separated precipitate is dried at 105 ° C., calcined at 300 ° C., and the powder is compressed into tablets. (RF Patent No. 1774556, B01J 37/04, 23/80, 1995).

Disadvantages of this method of preparing the catalyst are:

- the formation of a zinc-aluminum precursor (stabilizer) with a spinel structure does not provide the accepted conditions for treating aluminum hydroxide with an ammonia-carbonate zinc solution at a temperature of 65-70 ° C without adequate aging and control over the degree of its decomposition: zinc aluminum zinc (ZnAl ₂ O ₄ ) In the form of a cation (Zn ²⁺ );

- the homogeneity of the crystallochemical composition of the precipitated catalyst mass when the reaction mixture is fed to the reactor at a certain rate and the total concentration of copper and zinc is maintained at a level of 100-120 g / l will not provide without control over the amount of precipitated mass and the specified ratio of copper to zinc in the liquid phase of the reactor, Since the ammonium-carbonate zinc solution is less stable and will precipitate much faster;

- The use of freshly precipitated aluminum hydroxide as a raw material considerably complicates the technology of catalyst preparation: the production of hydroxide by precipitation from nitrate salts requires careful washing away from nitrate ions.

The technical result to which the invention is directed is the creation of a simple and economical technology for the preparation of copper-aluminum catalysts that do not have harmful wastewater and gas emissions and ensures the production of highly active, stable and mechanically strong catalysts.

The technical result is achieved in the first variant of the catalyst preparation process , which includes the production of ammonia-carbonate solutions of copper and zinc, treatment of the aluminum-containing raw material with an ammonia-carbonate zinc solution, mixing of the processed aluminum-containing raw material or its mixture with raw aluminum containing raw materials and copper and zinc compounds, Suspending at an elevated temperature and stirring, separating the resulting catalyst mass from the solution, drying, calcining and granulating, according to the invention, treatment of the aluminum-containing feed with an ammonia-carbonate zinc solution is carried out at a temperature of 75-90 ° C. and kept under stirring until the decomposition of the ammonium carbonate zinc solution , And the mixing of the copper, zinc and aluminum-containing feed compounds is carried out in a dosage, maintaining the temperature in the reactor at 75-90 ° C. and a predetermined ratio of copper to zinc in the liquid phase of the resulting slurry, the zinc compounds being introduced into the reactor in the form of an ammoniacal carbonate solution or oxide, Or basic carbonate, and the copper compound in the form of an ammonia-carbonate solution, and the atomic ratio of copper to zinc in the resulting catalyst is (0.55-2.2): 1 at an atomic aluminum content of 2.6 to 10.6.

According to a second variant of the process for preparing a catalyst comprising the preparation of ammonium carbonate solutions of copper and zinc, mixing of the aluminum-containing feedstock and copper and zinc compounds, keeping the resulting slurry in the reactor at elevated temperature and stirring, separating the resulting catalyst mass from solution, drying, calcining and pelletizing, Mixing of the copper, zinc and aluminum-containing raw materials is carried out in a dosed manner while maintaining the temperature in the reactor at 75-90 ° C. and a predetermined ratio of copper to zinc in the liquid phase of the slurry, wherein the zinc compounds are introduced into the reactor as an ammoniacal carbonate solution or oxide or basic carbonate, And the copper compound in the form of an ammonia-carbonate solution, and the atomic ratio of copper to zinc in the resulting catalyst is (0.55-2.2): 1 at an atomic aluminum content of 2.6 to 10.6.

In both the first and second embodiments of the process, aluminum hydroxide or oxide compounds having a predominantly fine crystalline structure up to 100 Å or having undergone mechanochemical activation are used as the aluminum-containing raw material.

Distinctive features of the variants of the method according to the present invention are that in the first variant, the treatment of the aluminum-containing raw material with an ammonia-carbonate zinc solution is carried out at a temperature of 75-90 ° C and kept under stirring until the decomposition of the ammonia-carbonate zinc solution, and the mixing of copper, zinc compounds And the aluminum-containing feedstock are dosed in a controlled manner maintaining the temperature in the reactor at 75-90.degree. C. and a predetermined ratio of copper to zinc in the liquid phase of the slurry, the zinc compounds being introduced into the reactor as an ammonia-carbonate solution or an oxide or base carbonate, and the copper compound in In the form of an ammoniacal carbonate solution, and the atomic ratio of copper to zinc in the resulting catalyst is (0.55-2.2): 1 at an atomic aluminum content of 2.6 to 10.6, and in the second embodiment, mixing copper, zinc compounds And aluminum-containing raw materials and dosed under the same conditions as in the first variant of the process.

Further distinctive features for both the first and second embodiments of the method are that aluminum hydroxide or oxide compounds having a predominantly fine crystalline structure up to 100 Å or having undergone mechanochemical activation are used as the aluminum containing raw material.

The proposed invention corresponds to the patentability condition - novelty , because the technical level could not find a technical solution, the essential features of which would completely coincide with all the features available in the independent claims.

And the proposed invention corresponds to the condition of patentability - an inventive step , because it was not possible to find a technical solution from the state of the art, the distinguishing features of which provided the same technical tasks for solving which the invention was directed.

The invention is illustrated by the following examples.

To prepare the catalysts presented in the examples below, ammonium carbonate solutions of copper and zinc were used, obtained by dissolving their oxides in solutions of ammonium carbonate with a specified ratio of NH ₃ and CO ₂ . For the preparation of solutions, basic copper and zinc salts or their metals can be used. In the solutions prepared, the concentration of copper or zinc was 100-120 g / l and the weight ratio of Cu (Zn): NH ₃ : CO ₂ = 1: 1.25: 0.8.

Example 1
0.325 L of an aqueous suspension containing 18.9 g of aluminum hydroxide with a boehmite structure (AlOOH) and a crystal size of 80-100 Å is introduced into the decomposition reactor, heated to 80-85 ° C. and 0.11 L of an ammonia-carbonate zinc solution containing (In grams): Zn - 10.5; NH ₃ - 13.2; CO ₂ - 8.5. The content of the reactor is maintained at a temperature of 80-85 ° C and vigorous stirring until the decomposition of the ammonium-carbonate zinc solution ends. Then, 0.56 liters of a mixed ammoniacal carbonate solution of copper and zinc containing (in grams) are introduced into the reactor: Cu-28, Zn-28.8, NH ₃ -71.8, CO ₂ -46.5, , That the ratio of copper to zinc in the liquid phase of the reactor was at the level of 2.1-2.2. At the end of the infusion of the solution, the suspension in the reactor is stirred to equalize the concentrations and sub-decompose the residues of the ammonia-carbonate salts to an NH ₃ content in the solution of 2-3 g / l. The resulting catalyst mass is filtered, dried and calcined at a temperature of 280-290 ° C to a volatile content in the calcined mass of 8-15% by weight, and then the resulting powder is compressed into tablets.

In the catalyst prepared, the ratio of Cu: Zn = 0.71 and the atomic content of Al is 7.62.

Example 2
0.325 liters of an aqueous suspension containing 24 g of technical aluminum hydroxide - AL (OH) ₃ , which has undergone mechanochemical activation in a bead mill (30 min), is poured into the reactor, it is heated to 85-90 ° C and 0.11 L of an ammonia-carbonate solution Zinc, containing (in grams): Zn - 10.5; NH ₃ - 13.2; CO ₂ - 8.5. The contents of the reactor are maintained at this temperature until the end of the decomposition of the ammonia-carbonate zinc solution, after which 49 g of zinc oxide is introduced into the reactor and 0.28 l of an ammonium-carbonate solution of copper is started to be dosed, maintaining a copper concentration in the liquid phase of 2.0-2.5 G / l. The catalyst is then prepared as in Example 1.

Example 3
The reactor is filled with 0.325 liters of an aqueous suspension containing 16 g of active aluminum oxide - Al ₂ O ₃ , heated to 75 ° C and 0.11 L of an ammonia-carbonate zinc solution containing (in grams): Zn-10.5; NH ₃ - 13.2; CO ₂ - 8.5 and kept with stirring until the decomposition of the ammonia-carbonate zinc solution ends, then 0.28 liters of ammonium carbonate copper solution is poured into the reactor and 68.5 g of basic zinc carbonate 0,9 ZnCO ₃ 0 are dosed, 1 Zn (OH) ₂ , maintaining the temperature in the reactor at 75 ° C and the ratio Cu: Zn in the liquid phase at the level of 0.75. Further preparation as in Example 1.

Example 4
0.325 L of an aqueous suspension containing 18.9 g of boehmite is poured into the reactor, heated to 87-88 ° C and 0.11 L of an ammonia-carbonate zinc solution is added, the contents of the reactor are maintained at this temperature and stirred until the decomposition of the ammonium carbonate zinc solution , Then 0.28 L of the ammoniacal carbonate solution of copper is poured into the reactor and immediately starts to dose 0.393 liters of the ammonia-carbonate zinc solution, maintaining the desired temperature and the ratio of Cu: Zn in the liquid phase of the suspension at the level of 0.75 in the reactor. The resulting suspension of the catalyst mass is thoroughly mixed, and then the preparation is carried out as in Example 1.

Example 5
0.325 L of an aqueous suspension containing 18.9 g of boehmite is poured into the reactor, heated to 75 ° C., 0.11 L of an ammonia-carbonate zinc solution is added. The slurry is held at a predetermined temperature until the decomposition of the ammonia-carbonate zinc solution is complete, then 0.28 L of an ammoniacal carbonate solution of copper is poured into the reactor and zinc oxide is dosed, maintaining the temperature in the reactor and the Cu: Zn ratio in the liquid phase at 0, 71. Further preparation as in Example 1.

Example 6
0.325 L of an aqueous suspension containing 18.9 g of aluminum hydroxide with a boehmite structure (AlOOH) is introduced into the decomposition reactor, heated to 75 ° C and 0.06 L of an ammonia-carbonate zinc solution containing (in grams): Zn-5, 7, NH ₃ - 7.2, CO ₂ - 4.6. The content of the reactor is maintained at a temperature of 75-80 ° C and vigorously stirred to an NH ₃ content in the liquid phase, close to 1 g / l. Then, keeping the set temperature, 0.61 liters of ammonium-carbonate solution of copper and zinc containing (in grams): Cu-28, Zn-33.6, NH ₃ -77.8, CO ₂ -50.4 At a rate ensuring the concentration of copper and zinc in the liquid phase of the suspension corresponding to Cu: Zn = 2.3-2.4. The catalyst is then prepared as in Example 1.

The prepared catalyst has a composition corresponding to a ratio of Cu: Zn = 0.71 and an atomic aluminum content of 7.62.

Example 7
0.325 liters of an aqueous suspension containing 9.5 g of boehmite-AlOOH and 12 g of technical aluminum hydroxide are poured into the reactor and heated to 90 ° C. 0.11 l of ammonium carbonate zinc solution is poured into the suspension and, with stirring, is maintained until the decomposition of the ammonium carbonate zinc solution, after which the mixture of ammonium carbonate solutions of copper and zinc starts to be dosed, maintaining the desired temperature and the Cu: Zn ratio in the liquid phase, Which is equal to 2.1-2.5. At the end of the dosage of the solutions, the suspension of the catalyst mass is thoroughly mixed and further prepared as in Example 1.

Example 8
0.325 L of an aqueous suspension containing 18.9 g of aluminum hydroxide with a boehmite structure (AlOOH) is introduced into the reactor, heated with vigorous stirring to 88-90 ° C, and a 0.67 L of an ammonia-carbonate solution of copper, zinc containing (In grams): Cu - 28, Zn - 39.3, NH ₃ - 85, CO ₂ - 55, dosing it at a rate ensuring the ratio of Cu: Zn in the liquid phase of the suspension at 2.5. Further, the preparation and composition of the catalyst as in Example 1.

Example 9
0.325 L of an aqueous suspension containing 18.9 g of boehmite (AlOOH) is introduced into the reactor, heated to 85-88 ° C, 0.28 L of an ammoniated carbonate solution of copper containing (in grams) Cu-28, MH ₃ - 35.5, CO ₂ - 23.1, and with vigorous stirring, immediately begin to dose 0.39 liters of ammonia-carbonate zinc solution containing (in grams): Zn - 39.3, NH ₃ - 49.5, CO ₂ - 31.9, at a rate providing the ratio Cu: Zn = 2.5 in the liquid phase of the suspension. Further, the preparation and composition of the catalyst as in Example 1.

Example 10
0.325 L of an aqueous suspension containing 18.9 g of aluminum hydroxide with a boehmite structure is introduced into the reactor, heated to 80-85 ° C, 0.28 L of an ammoniated carbonate solution of copper containing (in grams): Cu-28, NH ₃ - 35.5, CO ₂ - 23.1, add 0.1 ammonium carbonate solution containing (in grams): NH ₃ - 14.5 and CO ₂ - 9.5, and with vigorous stirring, 49 g of zinc oxide (ZnO), maintaining the rate of its supply in the liquid phase of the reactor suspension, the ratio of Cu: Zn = 0.71-0.75. Further, the preparation and composition of the catalyst as in Example 1.

Example 11
0.325 liters of an aqueous suspension containing (in grams) 18.9 g of boehmite (AlOOH) are introduced into the decomposition reactor, heated to 77-80 ° C, 0.28 l of the prepared ammonium carbonate copper solution is poured, 0.1 l of the carbonate solution Ammonium containing (in grams): NH ₃ - 14.5, CO ₂ - 9.5, and with vigorous stirring, 59.3 g of the basic zinc carbonate powder are dispensed. Further, the preparation and composition of the catalyst as in Example 10.

Example 12
0.325 L of an aqueous suspension containing 16 g of active aluminum oxide ( Al ₂ O ₃ ), heated to a temperature of 85-88 ° C, 0.28 liters of the prepared ammoniacal carbonate solution of copper are poured, 0.1 liters of a solution of ammonium carbonate containing (in grams): NH ₃ - 14.5, CO ₂ - 9.5, and with intensive stirring, 49 g of zinc oxide (ZnO) are dosed. Further, the preparation and composition of the catalyst as in Example 10.

Example 13
0.325 L of an aqueous suspension containing 24.5 g of freshly precipitated aluminum hydroxide Al (OH) ₃ is introduced into the reactor, heated to 75-80 ° C, 0.28 of the prepared ammonium carbonate copper solution is poured, 0.1 l of a solution of ammonium carbonate , Containing (in grams): NH ₃ - 14.5, CO ₂ - 9.5, and ZnO is dosed with stirring while maintaining the Cu: Zn ratio in the liquid phase at the level of 0.71-0.75. Further, the preparation and composition of the catalyst as in Example 10.

Example 14
0.325 L of an aqueous suspension containing 24 g of technical aluminum hydroxide Al (OH) ₃ , which was mechanochemically treated in a bead mill for 30 minutes, was introduced into the reactor, the suspension was heated to 85-90 ° C, 0.28 L of the prepared ammonia-carbonate Solution of copper, add 0.1 liters of ammonium carbonate solution containing (in grams) NH ₃ - 14.5, CO ₂ - 9.5, and ZnO is dosed with vigorous stirring as in Example 13. Further, the preparation and composition of the catalyst, both in Example 10.

Example 15
0.2 liters of an aqueous suspension containing 5.9 g of aluminum hydroxide with a boehmite structure (AlOOH) having a crystal size of 80-100 Å is introduced into the decomposition reactor, heated to 75-80 ° C., 25 g of zinc oxide (ZnO) are poured and dosed 0.44 L of an ammonium carbonate solution of copper containing (in grams): Cu-44, NH ₃ -55.8, CO ₂ -36.3. The resulting suspension is maintained with vigorous stirring until the decomposition of ammonium carbonate solutions of copper and zinc (NH ₃ content in the liquid phase of the suspension is 2-3 g / l). Further, the preparation of the catalyst is carried out as in Example 1.

In the catalyst prepared, the ratio of Cu: Zn = 2.2, and the atomic content of aluminum (Al) is 2.6.

Example 16
0.42 L of an aqueous suspension containing 12.5 g of aluminum hydroxide with a boehmite structure (AlOOH) is introduced into the decomposition reactor, heated to 85-90 ° C., 0.2 l of an ammoniated carbonate solution of copper containing (in grams): Cu - 20, NH ₃ - 25.3, CO ₂ - 16.5. Into this suspension, 0.36 L of an ammonia-carbonate zinc solution containing (in grams): Zn-36, NH ₃ -45.4, CO ₂ -29.3, is dispensed into the resulting suspension at a rate providing a Cu: Zn ratio of Liquid phase of the suspension at a level of 3.0-3.5. Further, the preparation of the catalyst is as in Example 1. In the catalyst prepared, the ratio Cu: Zn = 0.55, and the atomic aluminum (Al) content is 10.6.

The proposed options for the preparation of a catalyst based on copper, zinc and aluminum provide the following advantages:

- so treatment of aluminum-containing raw materials with an ammonium-carbonate zinc solution at a temperature of 75-90 ° C, accompanied by its decomposition, leads to the formation of zinc cations (Zn ²⁺ ) capable of interacting with aluminum-containing raw materials to form a highly disperse thermally stable zinc-aluminum compound, Structure (ZnAl ₂ O ₄ ), providing formation in the catalyst of a fine-crystalline, stable copper-zinc compound responsible for its catalytic properties;

- the dosed introduction of the main components of the catalyst into the decomposition reactor is caused by the fact that ammonium carbonate solutions of copper and zinc have different resistance to decomposition: the instability constant of the zinc solution is 3-4 times higher than that for a similar solution of copper. Therefore, their joint decomposition leads to the enrichment of the formed solid decomposition products with zinc compounds: the catalyst mass is obtained non-uniform, without proper coprecipitation of copper and zinc. Maintaining a predetermined ratio between copper and zinc in the liquid phase of the reactor by dosing the components, taking into account the different decomposition rates of their ammoniacal carbonate solutions and the chemical composition of the catalyst, makes it possible to form a catalyst mass with a homogeneous phase and crystallochemical composition that determines the high catalytic properties of the finished catalyst;

- when the zinc compounds are introduced into the reactor in the solid state as an oxide (carbonate), an unexpected positive effect is achieved: a self-regulating decomposition-formation process is created: the ammonium-carbonate solution of copper decomposes and the released NH ₃ and CO ₂ decomposition products interact with zinc oxide to form Ammonium carbonate solution, which, decomposing together with an ammoniacal-carbonate solution of copper, forms a more uniform copper-zinc structure precipitated on an aluminum-containing feedstock. The NH ₃ and CO ₂ liberated during this process dissolve another portion of the zinc oxide (carbonate). With this method of introducing zinc compounds, along with obtaining a homogeneous highly dispersed catalyst mass responsible for the high catalytic properties of the finished catalyst, the manufacturing technology is simplified and cheaper: the consumption of the ammonium salt decreases and the duration of the decomposition step is reduced;

- the use of ready-made, commercially available hydroxides and aluminum oxides with a fine-crystalline structure and, accordingly, sufficiently reactive, allows the production of catalysts with high catalytic properties, including heat resistance and stability, simplifying and cheaper technology by eliminating the step of obtaining freshly precipitated aluminum hydroxide, having Contaminated wastewater.

The characteristics of the catalytic properties of the catalyst samples obtained in accordance with the variants of the proposed method are given in the table.

It follows from the table that copper-zinc-aluminum catalysts prepared according to the invention (examples 1-16) have high activity, thermal stability, selectivity with sufficient mechanical strength.

CLAIM

1. A process for the preparation of a copper-zinc-aluminum catalyst comprising the production of ammonium-carbonate solutions of copper and zinc, treatment of an aluminum-containing feedstock with an ammonia-carbonate zinc solution, mixing of a treated aluminum-containing feed or a mixture thereof with an untreated aluminum-containing feedstock and copper and zinc compounds, maintaining the resulting suspension at an elevated temperature in the reactor, and Stirring, separation of the resulting catalyst mass from the solution, drying, calcining and granulation, characterized in that the treatment of the aluminum-containing feedstock with an ammonia-carbonate zinc solution is carried out at a temperature of 75-90 ° C and kept under stirring until the decomposition of the ammonium-carbonate zinc solution, and mixing Copper compounds, zinc and aluminum-containing raw materials are carried out in a dosed manner, maintaining the temperature in the reactor at 75-90.degree. C. and a predetermined ratio of copper to zinc in the liquid phase of the resulting slurry, the zinc compounds being introduced into the reactor in the form of an ammoniacal carbonate solution or oxide or basic Carbonate, and the copper compound as an ammonia-carbonate solution, and the atomic ratio of copper to zinc in the resulting catalyst is (0.55-2.2): 1 at an atomic aluminum content of 2.6 to 10.6.

2. A process for the preparation of a copper-zinc-aluminum catalyst comprising the preparation of ammonium carbonate solutions of copper and zinc, mixing of aluminum-containing raw materials and copper and zinc compounds, maintaining the resulting slurry in the reactor at elevated temperature and stirring, separating the resulting catalyst mass from solution, drying, calcining and granulating, , That the mixing of the copper, zinc and aluminum-containing feed compounds is carried out in a dosage, maintaining the temperature in the reactor at 75-90.degree. C. and a predetermined ratio of copper to zinc in the liquid phase of the slurry, the zinc compound being introduced into the reactor as an ammoniacal carbonate solution or oxide, Or basic carbonate, and the copper compound as an ammonia-carbonate solution, and the atomic ratio of copper to zinc in the resulting catalyst is (0.55-2.2): 1 with an atomic aluminum content of 2.6 to 10.6.

3. The method according to claim 1 or 2, characterized in that the aluminum-containing raw material is aluminum hydroxide or oxide compounds having a predominantly fine crystalline structure up to 100Å or having undergone mechanochemical activation.

print version
Date of publication 05.12.2006гг

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