RU2782893C1 - Method for producing a metathesis catalyst for lower olefins, catalyst and application thereof - Google Patents

Abstract

FIELD: catalysts.

SUBSTANCE: invention relates to methods for producing catalysts by modifying the acidic properties of the active phase carrier of the catalyst, to a catalyst and to an application of the catalyst for synthesising ethylene or propylene, including the reaction of olefin metathesis, wherein a mixture of olefin hydrocarbons C₂-C₄ is used as a raw material. Method for producing an oxide catalyst involves treating a carrier containing aluminium oxide with a solution of molybdenum or tungsten compounds and subsequently calcining until a catalytically active phase in the form of molybdenum or tungsten oxides is formed on the carrier. Aluminium oxide or aluminium-containing zeolite or clay is taken as an alumina carrier. The carrier is pre-impregnated by wetness with a modifying solution of salts containing anions selected from the following: F^-, Cl^-, Br^-, I^-, BF₄ ^-, SiF₆ ^-, SO₄ ^2-, PO₄ ^3-, BO₃ ^3-. The impregnation is conducted for a time sufficient to replace the surface OH^- groups of the carrier with anions of the modifying salts before said anions are introduced in an amount from 0.1 to 15% wt. The resulting mass is held for at least 24 hours, dried, and calcined at 450 to 550°C. The modified carrier is treated with an aqueous solution of molybdenum or tungsten compounds capable of decomposing to the corresponding oxide after heat treatment, followed by drying and heat treatment at 450 to 550°C in an oxidising or inert medium, forming a catalytically active phase of Mo or W oxides on the carrier, containing oligomeric MoO_5/6 or WO_5/6 surface groups. The catalyst contains 1 to 15% wt. Mo or W oxide on an alumina carrier.

EFFECT: production of highly active and selective heterogeneous catalysts.

6 cl, 1 dwg, 3 tbl, 40 ex

Description

The present invention relates to methods for preparing and modifying olefinic hydrocarbon metathesis catalysts by modifying the acidic properties of the catalyst active phase support. The catalysts described here can be successfully used for the synthesis of propylene and ethylene by the metathesis of unsaturated hydrocarbons.

A known method of metathesis of olefins with ethylene on a catalyst consisting of 0.1-25.0% of the mass. SnO ₂ , MoO ₃ , 0.01-1.00% wt. - fluorine, carrier SiO ₂ - the rest (US 3923920, 1975).

The disadvantage of the method of preparing catalysts in the known method is the use of pure SiO ₂ as a carrier, which worsens the interaction of the active phase with the carrier and, as a result, requires elevated temperatures during the metathesis process (>200°C) to achieve maximum conversion.

A known method of modifying metathesis catalysts with an active component in the form of oxides of Mo, W or Re with fluorine ions. The mass ratio of the content of fluorine to the oxide of the active component in the catalyst is (0.065-0.20):1. Fluorine enters the catalyst in the form of soluble inorganic salts such as NaF, KF, CdF ₂ , etc. The use of the resulting catalyst for the metathesis of a mixture of isobutylene with a fraction of olefins C ₃ -C ₂₀ is proposed (US 3697613, 1972).

A known method of preparing rhenium oxide catalysts on a substrate of γ-alumina containing fluorine as an anion. The content of the components in the catalyst in terms of γ-alumina, is in wt.%: Re ₂ O ₇ - 0.1-10.0; fluorine - 0.2-4.0 According to the method, a solid carrier containing fluorine is treated with a solution of rhenium-containing compounds and calcined at 600-900°C (RU 2292951, 2007).

The disadvantage of this method is the use of expensive and highly volatile rhenium as an active component, as well as uncontrolled distribution of fluorine on the carrier, which is γ-Al ₂ O ₃ .

A known method for producing propylene from ethylene by simultaneous dimerization and metathesis of the latter on a catalyst. The catalyst consists of rhenium oxide, tungsten oxide and palladium on an oxide carrier, which is aluminum oxide. The composition of the catalyst in wt. %: rhenium oxide 0.5-2.0; tungsten oxide 5.0-10.0; palladium 0.01-0.25; oxide carrier - the rest. According to the method, aluminum oxide can be treated with solutions of inorganic acids, which will increase the selectivity of the catalyst to the formation of propylene (RU 2370314, 2009).

The disadvantages of this method are the need to treat the carrier with acids, which significantly increases the requirements for equipment, as well as the introduction of expensive palladium in the preparation of the catalyst.

The prior art known industrially used catalysts for the process of metathesis of lower olefins based on MoO ₃ , WO ₃ deposited on a substrate. It has been found that the active phase (MoO ₃ ) on a support can be represented by various types of groups: isolated MoO ₄ , oligomeric MoO _5/6 groups, and crystalline MoO ₃ nanoparticles. It has been suggested in the literature that the stability and activity of the groups mentioned above differ significantly. The isolated MoO ₄ surface groups are stable but inactive during the metathesis of lower olefins at 25-200°C. Oligomeric MoO _5/6 surface groups, on the contrary, are converted into centers active for metathesis at a lower temperature. The ability of surface MoOx groups to activate is related to the acidity of the support. The more active forms of MoO _5/6 probably form on the more acidic HO-Al(IV) hydroxyl groups, while the MoO ₄ appears to form on the more basic HO-Al(V/VI). Crystalline MoO ₃ nanoparticles are inactive in olefin metathesis and their presence reduces the ability of propylene to activate MoOx groups. It was noted that the acidity of the support is an important factor affecting the amount of catalytically active oligomeric forms of MoOx; therefore, a high proportion of oligomeric groups and, as a consequence, a large proportion of easily activated MeOx fragments can be achieved on a support with optimal acidity. (Chakrabarti A., Wachs IE Molecular Structure-Reactivity Relationships for Olefin Metathesis by Al ₂ O ₃ -Supported Surface MoOx Sites // ACS Catal. 2018. Vol. 8, No. 2. P. 949-959, see chapters 4.1 and 2.1).

The method of obtaining the catalyst described in the above article, and adopted by us as a prototype, is as follows. Take 2 types of commercial carriers of aluminum oxide with different acidity of the surface. According to the method described in the article, the aluminum oxide support is calcined in air at 500°C for 16 hours, impregnated with a solution of ammonium paramolybdate, dried at 120°C for 2 hours, the temperature is raised to 500°C at a rate of 1° C/min, held at final temperature for 4 hours. In this way, catalysts containing 13, 18, 20 wt % MoO ₃ on an alumina support were obtained.

Raman spectroscopy revealed the presence on the surface of the tested alumina carriers of both isolated MoO ₄ and oligomeric MoO _5/6 groups. However, in this source of information there is no information about the methods that make it possible to obtain a catalyst on an alumina carrier containing predominantly oligomeric surface MoO _5/6 groups.

In the prior art, we have not found methods that make it possible to increase the acidity of the support in such a way that, upon further introduction of the catalytic phase of molybdenum and tungsten oxides into the catalyst, these oxides are present on the surface of the support mainly in the form of oligomeric MoO _5/6 or WO _5/6 groups.

The objective of the present invention is to develop a method for obtaining highly active and selective heterogeneous catalysts for the metathesis of lower olefins by modifying the initial support containing alumina, which provides an increased formation of highly active oligomeric MeOx forms (Me = Mo, W) on the surface of the support, and as a result, improves catalytic properties of the target product.

The problem is solved by the described method for obtaining an oxide catalyst for the metathesis of lower olefinic hydrocarbons, which includes the deposition of a catalytically active phase in the form of molybdenum or tungsten oxides on an alumina carrier, in which aluminum oxide or an aluminum-containing zeolite, or clay is taken as an alumina carrier. The carrier is pre-impregnated according to its moisture capacity with a modifying solution of salts containing anions selected from the series: F^-, Cl^-, Br^-, I^-, bf_four ^-, SiF₆ ^-, SO_four ^2-, PO_four ^3-, BO₃ ³ for a period of time sufficient to replace the surface OH^- carrier groups on the mentioned anions of modifying salts, providing the introduction of modifier anions in an amount of from 0.1 to 15 wt. %, maintaining the resulting mass for at least 24 hours, drying and calcining at 450-550 ° C, processing the modified carrier with an aqueous solution of molybdenum or tungsten compounds capable of decomposing to the corresponding oxide during heat treatment, after which drying and heat treatment are carried out at 450-550 ° С in an oxidizing or inert atmosphere with the formation of a catalytically active phase of oxides of Mo or W containing oligomeric MoO_5/6 or WO_5/6 surface groups.

Preferably, as compounds of molybdenum and tungsten capable of decomposition during heat treatment, tetravalent oxides of molybdenum or tungsten, paramolybdate or ammonium paratungstate, or molybdic or tungstic acids are used, while an aqueous solution of these compounds is taken based on the formation of 1-15 masses on the carrier .% oxide Mo or W.

The problem is also solved by the catalyst obtained as described above, intended for the metathesis of lower olefinic hydrocarbons, containing 1-15 wt. % oxide Mo or W on alumina carrier, in which the catalytically active phase contains oligomeric forms, MoO _5/6 or WO _5/6 , the proportion of which is 25-40%.

The problem is also solved by using the obtained catalyst for the synthesis of propylene, including the metathesis reaction of a mixture of olefinic hydrocarbons C ₂ -C ₄ in the presence of a catalyst corresponding to this invention, as well as using the obtained catalyst for the synthesis of ethylene, including the reaction of metathesis of a mixture of olefinic hydrocarbons C ₂ -C ₄ or propylene alone in the presence of a catalyst according to the invention.

The use of catalysts obtained by the claimed method allows, without changing the conditions of the metathesis reaction, to significantly increase, relative to the prototype, the conversion rates of the feedstock in the metathesis of lower olefins while maintaining selectivity at a high level.

The possibility of carrying out the invention is illustrated below by specific examples of obtaining the claimed catalyst and information about its effectiveness, shown in tables 1-3.

Figure 1 schematically depicts 3 types of fragments of the active phase, which, under different conditions of the process of obtaining a catalyst, are able to form on a carrier.

Example 1. (comparative - according to the prototype).

The reference molybdenum oxide catalyst is prepared by impregnating 10 g of γ-alumina with an aqueous solution of ammonium paramolybdate (NH ₄ ) ₆ Mo ₇ O ₂₄ at 30°C for 24 hours, dried at 110°C, and heat treated in air at 550° C within 3 hours. The final catalyst contains 9 wt. % MoO ₃ based on γ-alumina. Before carrying out catalytic experiments, here and in all cases described below, the catalyst is purged with nitrogen at 500°C at a rate of 30 ml/min. within 1 hour.

The results of testing the proposed oxide catalysts in the reaction of propylene metathesis to ethylene and butylenes are disclosed in further examples, information about which is combined in Table 1 and Table 2. In the described examples, the experimental parameters are as follows: m catalyst = 3 g, fraction 0.5-1 mm. Propylene feed rate = 30 ml/min., T reaction = 100°C, reactor pressure 9 atm. A sample for analysis of products on a chromatograph and mass spectrometer was taken 60 and 120 minutes after the establishment of the declared reaction mode.

Example 2

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 1, however, before the stage of processing the carrier with molybdenum compounds, the stage of modifying the carrier is carried out. The modification stage includes impregnation of a 0.5-1 mm fraction of the carrier with a modifier salt solution in the required amount (anions and their amount are given in the tables below). After impregnation, the resulting mixture is kept for a day, dried at 110°C for 3 hours and calcined for 5 hours at the temperatures indicated in the tables below. As a carrier modifier in example 2, an ammonium fluoride solution is used in an amount that provides a mass fraction of fluorine in the catalyst of 0.1 wt. % based on γ-alumina. The catalyst was tested in the reaction of propylene metathesis under the conditions of example 1 corresponding to the prototype.

The specific conditions of the production method for all examples are summarized in tables 1-3.

Example 3

The preparation of a molybdenum-containing oxide catalyst is carried out as in example 2, but an ammonium fluoride solution is used as a carrier modifier so that the mass fraction of fluorine in the final catalyst is 2 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 4

The production of a molybdenum-containing oxide catalyst is carried out as in example 2, but an ammonium fluoride solution is used as a carrier modifier so that the mass fraction of fluorine in the final catalyst is 3 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 5

The production of a molybdenum-containing oxide catalyst is carried out as in example 2, but an ammonium fluoride solution is used as a carrier modifier so that the mass fraction of fluorine in the final catalyst is 6 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 6

The production of a molybdenum-containing oxide catalyst is carried out as in example 2, but an ammonium fluoride solution is used as a carrier modifier so that the mass fraction of fluorine in the final catalyst is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 7

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but as a carrier modifier, an aqueous solution of NH ₄ BF ₄ is used so that in the final catalyst the mass fraction of the anion BF ₄ ^- is 0.1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 8

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of NH ₄ BF ₄ is used as a carrier modifier so that in the final catalyst the mass fraction of the anion BF ₄ ^- is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 9

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of NaCl is used as a carrier modifier so that the mass fraction of chlorine in the final catalyst is 0.1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 10

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of NaCl is used as a carrier modifier so that the mass fraction of chlorine in the final catalyst is 1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 11.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of NH ₄ Br is used as a carrier modifier so that the mass fraction of bromine in the final catalyst is 1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 12.

The production of a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of NH ₄ Br is used as a carrier modifier so that the mass fraction of bromine in the final catalyst is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 13

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of NH ₄ I is used as a carrier modifier so that in the final catalyst the mass fraction of iodine is 1 mass. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 14

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of NH ₄ I is used as a carrier modifier so that in the final catalyst the mass fraction of iodine is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 15

The production of a molybdenum-containing oxide catalyst is carried out as in example 2, but first, the mass of ammonium paramolybdate is taken such that the catalyst contains 15 wt. % MoO ₃ based on γ-alumina. Secondly, an ammonium fluoride solution is used as a carrier modifier so that the mass fraction of fluorine in the catalyst is 1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 16

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of (NH ₄ ) ₂ SiF ₆ is used as a carrier modifier so that in the final catalyst the mass fraction of the SiF ₆ ^2- anion is 0.1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 17.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of (NH ₄ ) ₂ SiF ₆ is used as a carrier modifier so that in the final catalyst the mass fraction of the SiF ₆ ^2- anion is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 18.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of Na ₂ SO ₄ is used as a carrier modifier so that in the final catalyst the mass fraction of the SO ₄ ^2- anion is 1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 19.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of Na ₂ SO ₄ is used as a carrier modifier so that in the final catalyst the mass fraction of the SO ₄ ^2- anion is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 20.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of Na ₃ PO ₄ is used as a carrier modifier so that in the final catalyst the mass fraction of the PO ₄ ^3- anion is 1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 21.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of Na ₃ PO ₄ is used as a carrier modifier so that in the final catalyst the mass fraction of the PO ₄ ^3- anion is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 22.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of H ₃ BO ₃ is used as a carrier modifier so that in the final catalyst the mass fraction of the BO ₃ ^3- anion is 0.1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 23.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but an aqueous solution of H ₃ BO ₃ is used as a carrier modifier so that in the final catalyst the mass fraction of the BO ₃ ^3- anion is 15 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 24 (comparative, carried out under the conditions of the prototype without the stage of modifying the support, the support is zeolite, the catalytic phase is WO ₃ ).

The reference tungsten oxide catalyst is obtained by impregnating 10 g of the Na-form of zeolite ZSM-5 (Si/Al=40) with an aqueous solution of ammonium paratungstate (NH ₄ ) ₁₀ H ₂ W ₁₂ O ₄₂ at 30°C for 24 hours, dried at 110 °C and carry out heat treatment in an inert atmosphere at 500°C for 5 hours. The final catalyst contains 9 wt. % WO ₃ in terms of aluminum oxide. The catalyst was tested in the propylene metathesis reaction as in Example 1, except for the reaction temperature, which is 200°C.

Example 25.

The preparation of a tungsten-containing oxide catalyst is carried out as in example 24, however, the support is pre-impregnated with a modifying salt solution. As a carrier modifier, a solution of sodium fluoride is used in an amount that provides a fluorine content of 0.1 wt. % based on Na- form of zeolite ZSM-5. After that, the mass is kept for a day, dried, and heat-treated under the conditions indicated in the table. The catalyst was tested in the propylene metathesis reaction analogously to example 1, except for the reaction temperature, which is 200°C.

Example 26.

Getting tungsten-containing oxide catalyst is carried out as in example 24, but as the carrier of the active phase using clay - kaolinite (Si/Al=0.6). A solution of sodium fluoride is used as a carrier modifier so that the mass fraction of fluorine in the final catalyst is 1 wt. % based on the media. The catalyst was tested in the propylene metathesis reaction as in example 1, except for the reaction temperature, which is 200°C.

Example 27.

The production of a tungsten-containing oxide catalyst is carried out as in example 24, but kaolinite (Si/Al=0.6) is used as the carrier of the active phase. A solution of sodium fluoride is used as a carrier modifier so that the mass fraction of fluorine in the final catalyst is 15 wt. % based on the media. The catalyst was tested in the propylene metathesis reaction as in example 1, except for the reaction temperature, which is 200°C.

Example 28.

The preparation of a tungsten-containing oxide catalyst is carried out as in example 24, but the Na-form of MOR zeolite (Si/Al=5) is used as the carrier of the active phase. A solution of sodium chloride is used as a carrier modifier so that the mass fraction of chlorine in the final catalyst is 2 wt. % based on the zeolite carrier. The catalyst was tested in the propylene metathesis reaction as in example 1, except for the reaction temperature, which is 200°C.

Example 29.

Obtaining a molybdenum-containing oxide catalyst is carried out as in example 2, but molybdenum is applied at the rate of 1 wt. % MoO3 on the carrier, and ammonium fluoride solution is used as the carrier modifier so that the mass fraction of fluorine in the final catalyst is 2 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1.

Example 30.

The preparation of a tungsten-containing oxide catalyst is carried out as in example 24, but clay - kaolinite (Si/Al=0.6) is used as the carrier of the active phase, and tungsten is applied at the rate of 1 wt. % WO ₃ on the media. A solution of sodium fluoride is used as a carrier modifier so that the mass fraction of fluorine in the final catalyst is 1 wt. % based on the media. The catalyst was tested in the propylene metathesis reaction as in example 1, except for the reaction temperature, which is 200°C.

Example 31.

The preparation of the catalyst is analogous to example 2. The catalyst was tested in the reaction of propylene metathesis and conditions similar to example 1, except for the pressure, which was equal to 1 atm.

Example 32.

The preparation of the catalyst is analogous to example 4. The catalyst was tested in the reaction of propylene metathesis and conditions similar to example 1, except for the pressure, which was equal to 1 atm.

Example 33.

A molybdenum-containing oxide catalyst is obtained by impregnating 10 g of the Na-form of ZSM-5 zeolite, which is preliminarily modified with an ammonium fluoride solution so that the mass fraction of fluorine in the final catalyst is 3 wt. % based on the carrier (Si/Al=40). The modified carrier is impregnated with an aqueous solution of ammonium paramolybdate (NH ₄ ) ₆ Mo ₇ O ₂₄ at 30°C for 24 hours, dried at 110°C and heat treated in air at 550°C for 5 hours. The final catalyst contains 9 wt. % MoO ₃ based on the media. The catalyst was tested in a propylene metathesis reaction under conditions analogous to Example 1, except for the pressure, which was 1 atm.

Example 34.

Obtaining a tungsten-containing oxide catalyst is carried out as in example 9, but kaolinite (Si/Al=0.6) is used as the carrier of the active phase. A solution of sodium chloride is used as a carrier modifier so that the mass fraction of chlorine in the final catalyst is 1 wt. % based on the media. The catalyst was tested in the propylene metathesis reaction as in Example 1, except for the reaction temperature, which was 200° C. and the pressure, which was 1 atm.

Example 35.

Obtaining a tungsten-containing oxide catalyst is carried out as in example 25, but an aqueous solution of (NH ₄ ) ₂ SiF ₆ is used as a carrier modifier so that in the final catalyst the mass fraction of the SiF ₆ ^2- anion is 0.1 wt. % based on γ-alumina. The catalyst was tested in the propylene metathesis reaction as in Example 1, except for the reaction temperature, which was 200° C. and the pressure, which was 1 atm.

Example 36.

Getting molybdenum-containing oxide catalyst is carried out as in example 2. The catalyst was tested in the reaction of metathesis of ethylene and butylene-2. Molar ratio of olefins in the feed stream = 1:1, other process parameters as in example 1.

Example 37.

Getting molybdenum-containing oxide catalyst is carried out as in example 7. The catalyst was tested in the reaction of metathesis of ethylene and butylene-2. Molar ratio of olefins in the feed stream = 1:1, other process parameters as in example 1.

Example 38.

Obtaining tungsten-containing oxide catalyst is carried out as in example 28. The catalyst was tested in the reaction of metathesis of ethylene and butylene-2. The molar ratio of olefins in the original stream = 1:1, the rest of the process parameters as in example 1, except for the temperature, which was 200°C.

Example 39.

Obtaining tungsten-containing oxide catalyst is carried out as in example 26. The catalyst was tested in the reaction of metathesis of ethylene and butylene-2. The molar ratio of olefins in the original stream = 1:1, the rest of the process parameters as in example 1, except for the temperature, which was 200°C.

Example 40.

Obtaining tungsten-containing oxide catalyst is carried out as in example 35. The catalyst was tested in the reaction of metathesis of ethylene and butylene-2. The molar ratio of olefins in the original stream = 1:1, the rest of the process parameters as in example 1, except for the temperature, which was 200°C.

The structure of the surface of the catalysts obtained according to the above examples was investigated by us by the method of Raman spectroscopy.

This method showed that on the surface of the catalysts, the proportion of the catalytically active phase represented by the oligomeric forms of MoO _5/6 or WO _5/6 is 25-40%. Similar studies of catalysts obtained by the prototype method using industrial alumina substrates showed that the proportion of MoO _5/6 oligomeric forms formed on the support is less than 25%. _.

The above examples 1-40 have shown the possibility of carrying out the invention within the scope of the formula. The results of testing catalysts in metathesis reactions, shown in the tables, showed the achievement of the claimed technical result in terms of increasing the catalytic activity of the target product, namely, increasing the degree of conversion with a high degree of selectivity. (Examples 1 and 24 refer to the method corresponding to the prototype).

Thus, the task is solved in the scope of the totality of the features of the claims and the claimed technical result is achieved. We have developed a new method for producing an oxide catalyst for the metathesis of lower olefinic hydrocarbons, in which the catalytically active phase on a support is represented by oligomeric forms of MoO _5/6 or WO _5/6 . The proportion of oligomeric forms on the catalyst obtained by the claimed method is higher than on the catalyst obtained by the known method. In addition, the invention expands the range of methods for the preparation of lower olefin metathesis catalysts and, accordingly, the range of effective catalysts for this purpose.

Table 1. Example No. active phase Modifier Carrier Ignition temperature, °C Propylene conversion, % Selectivity for C2+C4, % Type of Mass. % Type of Mass. % Type of Fraction of Al, wt. % After media modification After application of the active phase t=60 min. t=120 min. t=60 min. t=120 min. one MoO ₃ 9 - - _{Al2O3 _} 53 - 550 23.1 26.1 95.4 96.5 2 MoO ₃ 9 ^F- 0.1 _{Al2O3 _} 53 550 550 26.4 29.5 97.3 97.1 3 MoO ₃ 9 ^F- 2 _{Al2O3 _} 53 550 550 32.7 33.4 94.6 96.9 four MoO ₃ 9 ^F- 3 _{Al2O3 _} 53 550 550 32.7 35.7 98.3 98.0 5 MoO ₃ 9 ^F- 6 _{Al2O3 _} 53 550 550 41.6 41.3 99.1 99.0 6 MoO ₃ 9 ^F- fifteen _{Al2O3 _} 53 550 550 39.8 40.5 95.7 94.6 7 MoO ₃ 9 ^BF _4- 0.1 _{Al2O3 _} 53 500 550 27.2 28.3 95.2 95.6 eight MoO ₃ 9 ^BF _4- fifteen _{Al2O3 _} 53 500 550 35.6 35.7 95.0 95.3 9 MoO ₃ 9 ^Cl- 0.1 _{Al2O3 _} 53 500 550 24.9 27.1 96.6 96.9 ten MoO ₃ 9 ^Cl- fifteen _{Al2O3 _} 53 500 550 33.3 34.0 95.8 95.9 eleven MoO ₃ 9 ^br- one _{Al2O3 _} 53 500 550 26.0 26.0 95.1 95.5 12 MoO ₃ 9 ^br- fifteen _{Al2O3 _} 53 500 550 29.7 30.5 95.0 95.8 13 MoO ₃ 9 ^I- one _{Al2O3 _} 53 500 550 26.0 27.4 96.7 96.9 fourteen MoO ₃ 9 ^I- fifteen _{Al2O3 _} 53 500 550 29.1 29.8 96.5 96.5 fifteen MoO ₃ fifteen ^F- one _{Al2O3 _} 53 550 550 31.4 32.5 97.3 97.1 16 MoO ₃ 9 ^SiF6- _{_} 0.1 _{Al2O3 _} 53 500 550 27.1 28.0 96.1 96.3 17 MoO ₃ 9 ^SiF6- _{_} fifteen _{Al2O3 _} 53 500 550 34.7 35.2 96.0 96.1 eighteen MoO ₃ 9 SO ₄ ^2- one _{Al2O3 _} 53 500 550 26.3 26.4 95.3 96.7 19 MoO ₃ 9 SO ₄ ^2- fifteen _{Al2O3 _} 53 500 550 31.7 32.7 95.0 95.5 twenty MoO ₃ 9 PO ₄ ^3- one _{Al2O3 _} 53 500 550 25.4 25.9 96.2 96.3 21 MoO ₃ 9 PO ₄ ^3- fifteen _{Al2O3 _} 53 500 550 27.3 27.8 95.9 95.8 22 MoO ₃ 9 BO ₃ ^3- 0.1 _{Al2O3 _} 53 500 550 27.3 28.1 95.1 95.0 23 MoO ₃ 9 BO ₃ ^3- fifteen _{Al2O3 _} 53 500 550 32.5 32.5 95.9 96.3 24 _WO3 9 - ZSM-5 1.1 - 500 16.2 16.5 98.0 97.2 25 _WO3 9 ^F- 0.1 ZSM-5 1.1 450 500 19.4 21.9 98.2 98.5 26 _WO3 9 ^F- one Kaolinite 22.9 450 500 22.1 22.2 90.3 91.5 27 _WO3 9 ^F- fifteen Kaolinite 22.9 450 500 24.6 24.9 90.5 90.9 28 _WO3 9 ^Cl- 2 MOR 8.9 450 500 23.1 23.6 96.2 96.1 29 MoO ₃ one ^F- one _{Al2O3 _} 53 550 550 8.4 9.3 98.1 98.5 thirty _WO3 one ^F- one Kaolinite 22.9 450 500 6.5 6.7 97.4 97.6

Table 2. Example No. active phase Modifier Carrier Ignition temperature, °C Propylene conversion, % Selectivity for C2+C4, % Type of Mass. % Type of Mass. % Type of Fraction of Al, wt. % After media modification After application of the active phase t=60 min. t=120 min. t=60 min. t=120 min. 31 MoO ₃ 9 ^F- 0.1 _{Al2O3 _} 53 550 550 8.4 8.5 79.6 80.9 32 MoO ₃ 9 ^F- 3 _{Al2O3 _} 53 550 550 4.1 3.5 66.0 63.3 33 MoO ₃ 9 ^F- 3 ZSM-5 1.1 550 550 3.8 3.9 68.0 68.9 34 _WO3 9 ^Cl- one Kaolinite 22.9 450 500 8.3 8.4 78.1 78.0 35 _WO3 9 ^SiF6- _{_} 0.1 ZSM-5 1.1 450 500 9.8 9.7 81.6 82.1

Table 3 Example No. active phase Modifier Carrier Ignition temperature, °C Ethylene conversion, % Selectivity for C3, % Type of Mass. % Type of Mass. % Type of Fraction of Al, wt. % After media modification After application of the active phase t=60 min. t=120 min. t=60 min. t=120 min. 36 MoO ₃ 9 ^F- 0.1 _{Al2O3 _} 53 550 550 38.4 38.7 95.6 95.5 37 MoO ₃ 9 ^BF _4- 0.1 _{Al2O3 _} 53 500 550 40.2 40.8 93.2 93.4 38 _WO3 9 ^Cl- 2 MOR 8.9 450 500 33.7 34.8 96.2 96.3 39 _WO3 9 ^F- one Kaolinite 22.9 450 500 37.1 37.0 97.1 97.2 40 _WO3 9 ^SiF6- _{_} one ZSM-5 1.1 450 500 39.3 39.5 97.0 97.1

Claims (6)

1. A method for producing an oxide catalyst for the metathesis of lower olefinic hydrocarbons, which includes treating a support containing alumina with a solution of molybdenum or tungsten compounds and subsequent calcination until a catalytically active phase is formed on the support in the form of molybdenum or tungsten oxides, characterized in that the alumina support is taken aluminum oxide or aluminum-containing zeolite, or clay, the carrier is pre-impregnated by moisture capacity with a modifying solution of salts containing anions selected from the series: F ^- , Cl ^- , Br ^- , I ^- , BF ₄ ^- , SiF ₆ ^- , SO ₄ ^2- , PO ₄ ^3- , BO ₃ ^3- , impregnation is carried out for a period of time sufficient to replace the surface OH ^- groups of the carrier with anions of modifying salts before the introduction of the mentioned anions in an amount of from 0.1 to 15 wt.%, the resulting mass is kept for not less than 24 hours, dried and calcined at 450-550°C, the modified carrier is treated with an aqueous solution of molybdenum compounds and or tungsten, capable of decomposing during heat treatment to the corresponding oxide, after which drying and heat treatment are carried out at 450-550 ° C in an oxidizing or inert environment with the formation of a catalytically active phase of Mo or W oxides on the carrier, containing oligomeric MoO _5/6 or WO _{5 /6} surface groups. 2. The method according to claim 1, characterized in that tetravalent oxides of molybdenum or tungsten, paramolybdate or ammonium paratungstate or molybdic or tungstic acid are used as molybdenum and tungsten compounds capable of decomposition during heat treatment, while an aqueous solution of these compounds is taken from calculation of education on the carrier 1-15 wt.% oxide Mo or W. 3. Catalyst for the metathesis of lower olefinic hydrocarbons containing 1-15 wt.% oxide Mo or W on an alumina carrier, in which the catalytically active phase contains oligomeric forms, MoO _5/6 or WO _5/6 obtained by the method described in paragraph 1 . 4. The catalyst according to claim 3, in which the proportion of oligomeric forms is 25-40%. 5. The use of the catalyst described in claim 3 for the synthesis of ethylene, including an olefin metathesis reaction, in which a mixture of C ₂ -C ₄ olefinic hydrocarbons or propylene alone is used as a feedstock. 6. The use of the catalyst described in claim 3 for the synthesis of propylene, including an olefin metathesis reaction, in which a mixture of C ₂ -C ₄ olefinic hydrocarbons is used as a feedstock.

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