A catalyst and process for the oxidation of olefins to aldehydes and acids

Abstract

The invention provides a catalyst for preparing alkenals and alkenoic acids from alkylene oxides, which is composed of a carrier and an active component supported on the carrier, the active component having a general chemical formula of MoBiCoCaB a Co b Ca x B c O y wherein Mo is molybdenum, Bi is bismuth, Co is cobalt, Ca is calcium, B is boron, and O is oxygen; a, b, c, x and y are molar ratios of the respective elements; wherein 0.2≦a≦0.65, 0.3≦b≦1.0, 1.5≦x≦3, 0.4≦c≦1.5, and y is determined by the oxidation degrees of the other elements and is the number of oxygen atoms required to satisfy the valence of the other elements; the carrier is obtained by mixing molecular sieve powder, graphite and C 60 The catalyst has high alkylene conversion rate, high yield of alkenals and alkenoic acids, good stability and long service life.

Description

Technical Field

[0001] This invention relates to the field of industrial synthesis of acrylic acid, and more specifically to a catalyst and method for oxidizing olefins to prepare alkenal and olefinic acids. Background Technology

[0002] Acrylic acid is an important organic chemical raw material, mainly used to manufacture multifunctional polymer materials such as acrylates. It has wide applications in papermaking, leather, coatings, textiles, plastics, rubber, oil additives, and oil extraction. In recent years, the market demand for acrylic acid has exceeded supply. Therefore, research on how to produce acrylic acid efficiently and with high quality has become increasingly popular.

[0003] Currently, propylene is commonly used in industry to produce acrylic acid through oxidation. This method involves two stages: first, propylene undergoes gas-phase catalytic oxidation to produce acrolein, and then acrolein is further oxidized to acrylic acid. In this process, the performance of the catalyst directly determines the conversion rate of propylene and the yield of acrolein or acrylic acid. Furthermore, as a crucial consumable in this production system, the catalyst's stability and lifespan significantly impact the economic benefits of enterprises. Therefore, domestic and international companies have continuously conducted various research and improvements over the years.

[0004] Japanese Patent Publication Nos. 50 (19750)-1330A1 and 50-47915A1 disclose catalysts containing at least one element selected from potassium, rubidium, and cesium as the main component, and also supplemented with molybdenum, bismuth, iron, antimony, and nickel. TW518253B discloses a composite oxide catalyst that not only contains tungsten, bismuth, and iron, but also supplemented with other elements from the AE series. The A series is selected from at least one element from nickel or cobalt; the B series is selected from at least one element from sodium, potassium, rubidium, cesium, and thallium; the C series is selected from at least one element from alkaline earth metals; the D series is selected from at least one element from phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, boron, and zinc; and the E series is selected from at least one element from silicon, aluminum, titanium, or zirconium. The compositions of these disclosed catalysts are relatively complex, and there is still considerable room for cost reduction. Furthermore, the yields of acrylic acid and acrolein need to be improved.

[0005] Therefore, the present invention aims to provide a novel catalyst with a relatively simple composition, which is expected to reduce costs, and which has catalytic effects that are no less than those of the prior art. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a novel catalyst for the oxidation of olefins to prepare alkenal and olefinic acids.

[0007] This invention provides a catalyst for the oxidation of olefins to prepare enaldehydes and olefinic acids, comprising a support and an active component supported on the support, wherein the chemical formula of the active component is:

[0008] MoBi a Co b Ca x B c O y

[0009] Mo is molybdenum, Bi is bismuth, Co is cobalt, Ca is calcium, B is boron, and O is oxygen; a, b, c, x, and y are the molar ratios of each element; where 0.2≦a≦0.65, 0.3≦b≦1.0, 1.5≦x≦3, 0.4≦c≦1.5, and y is determined by the oxidation degree of each of the other elements and is the number of oxygen atoms required to satisfy the valence of each of the other elements; the support is composed of molecular sieve powder, graphite, and C. 60 The mixture is obtained.

[0010] In one manner, the content of the active component in the catalyst is 10 to 35 wt% by weight.

[0011] In one manner, the molecular sieve powder is one or more combinations of type A molecular sieve, type X molecular sieve, type Y molecular sieve, ZSM-5, SAPO-34, β molecular sieve or SAPO-11.

[0012] As one method, the amount of graphite added accounts for 2-8 wt% of the total weight of the carrier, C 60 The amount added is 0.05 to 0.5 wt% of the total weight of the carrier.

[0013] In one approach, the preparation method of the catalyst includes: preparing a mixture containing active component elements and the support; impregnating the support with the mixture of active component elements, followed by molding and calcination to obtain the catalyst.

[0014] As one method, the molecular sieve powder is treated at 45-55°C for 2-5 hours in a mixed acid solution obtained by mixing 8-15 wt% HF and 10-20 wt% hydrochloric acid in a 1:1 volume ratio, washed with water, dried, and ready for use.

[0015] As one method, the calcination conditions are: calcination at 460℃~650℃ for 3~8 hours.

[0016] The present invention also provides a method for preparing olefins and olefinic acids by oxidizing olefins, which uses a catalyst according to any one of the above descriptions.

[0017] In one embodiment, the olefin is propylene, the aldehyde is acrolein, and the olefinic acid is acrylic acid.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The catalyst of the present invention has relatively simple and readily available constituent elements, which helps to reduce the production cost of the catalyst.

[0020] 2. The catalyst of the present invention has a high propylene conversion rate and high yield of acrolein and acrylic acid, good stability and long service life, which can reduce the amount of catalyst used and improve economic benefits.

[0021] 3. The active components in the catalyst of the present invention work synergistically with the support to achieve better catalytic effect, improve catalyst stability, and extend service life. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] (1) Preparation of a mixture containing active component elements

[0025] The raw materials used are shown in the table below:

[0026] Active component elements Specific raw materials used Usage Mo Ammonium molybdate ((NH4)6Mo7O 24 )]]> 0.1mol Bi <![CDATA[Bismuth nitrate (Bi(NO3)3)]]> 0.14mol Co <![CDATA[Cobalt nitrate (Co(NO3)2)]]> 0.7mol Ca <![CDATA[Calcium chloride (CaCl2)]]> 2.1mol B <![CDATA[Ammonium borate (NH4HB4O7·3H2O)]]> 1.05mol

[0027] According to the above formula, ammonium molybdate, cobalt nitrate, calcium chloride and ammonium borate are dissolved in 2L of deionized water (50℃) to obtain solution A; 50g of 60wt% nitric acid and 200mL of deionized water are mixed evenly, and then bismuth nitrate is added and dissolved completely to obtain solution B; solution A and solution B are mixed evenly to obtain a mixed solution containing active component elements.

[0028] The active component in the prepared mixture has an elemental composition of MoBi. 0.2 CoCa3B 1.5 O 9.55 The weight is 340.15g.

[0029] (2) Preparation of carrier

[0030] Weigh out 2984.82g of type A molecular sieve powder, 61.23g of graphite (2wt% of the carrier), and 15.31g of C. 60 Mix evenly (0.5 wt% of the carrier) to form the carrier.

[0031] (3) Impregnation and molding

[0032] The carrier is dispersed in the above-mentioned mixture containing active component elements, stirred and impregnated for 14 hours, and then the water is evaporated to a state suitable for extrusion molding, and extruded into spherical particles with a particle size of 5 mm.

[0033] (4) Drying and roasting

[0034] The above spherical particles are dried at 110°C for 4 hours, and then calcined at 650°C for 3 hours.

[0035] The obtained catalyst, by weight, has the following composition: 10 wt% MoBi 0.2 CoCa3B 1.5 O 9.55 +90wt% carrier.

[0036] Example 2

[0037] The only difference from Example 1 is that the molecular sieve powder in Example 1 was purchased directly from the market, while the molecular sieve powder in this case has undergone the following optimization treatment:

[0038] The mixture of 10wt% HF and 20wt% hydrochloric acid in a 1:1 volume ratio was treated at 55℃ for 2 hours, washed with water, dried and ready for use.

[0039] Everything else remains the same as in Example 1.

[0040] Example 3

[0041] The difference from Example 1 is that the active component in the catalyst is 35% and the support is 65 wt%.

[0042] The active component was prepared according to the method in Example 1.

[0043] The support consists of 580.85g of type A molecular sieve powder, 50.54g of graphite (8wt% of the support), and 0.32g of C. 60 (0.05wt% of the carrier) are mixed evenly to form the mixture.

[0044] The obtained catalyst, by weight, has the following composition: 35 wt% MoBi. 0.2 CoCa3B 1.5 O 9.55 +65wt% carrier.

[0045] Example 4

[0046] (1) Preparation of a mixture containing active component elements

[0047] The raw materials used are shown in the table below:

[0048] Active component elements Specific raw materials used Usage Mo <![CDATA[Ammonium paramolybdate ((NH4)6Mo7O 24 )]]> 0.1mol Bi <![CDATA[Bismuth nitrate (Bi(NO3)3)]]> 0.455mol Co <![CDATA[Cobalt nitrate (Co(NO3)2)]]> 0.21mol Ca Calcium chloride 1.05mol B <![CDATA[Ammonium borate (NH4HB4O7·3H2O)]]> 0.28mol

[0049] According to the above formula, ammonium molybdate, cobalt nitrate, calcium chloride and ammonium borate are dissolved in 3L of deionized water (50℃) to obtain solution A; 50g of 60wt% nitric acid and 200mL of deionized water are mixed evenly, and then bismuth nitrate is added and dissolved completely to obtain solution B; solution A and solution B are mixed evenly to obtain a mixed solution containing active component elements.

[0050] The active component in the prepared mixture has an elemental composition of MoBi. 0.65 Co 0.3 Ca 1.5 B 0.4 O 6.375 The weight is 291.90g.

[0051] (3) Preparation of carrier

[0052] Weigh out 1106.87g of ZSM-5 molecular sieve powder, 58.37g of graphite (5wt% of the carrier), and 2.34g of C. 60 Mix evenly (0.2 wt% of the carrier) to form the carrier.

[0053] (3) Impregnation and molding

[0054] The carrier is dispersed in the above-mentioned mixture containing active component elements, stirred and impregnated for 20 hours, and then the water is evaporated to a state suitable for extrusion molding, and extruded into spherical particles.

[0055] (4) Drying and roasting

[0056] The above spherical particles are dried at 130°C for 2 hours, and then calcined at 460°C for 8 hours.

[0057] The obtained catalyst, by weight, has the following composition: 20 wt% MoBi. 0.65 Co 0.3 Ca 1.5 B 0.4 O 6.375 +80wt% carrier.

[0058] Example 5

[0059] The only difference from Example 4 is that the molecular sieve powder in Example 4 was purchased directly from the market, while the molecular sieve powder in this case has undergone the following optimization treatment:

[0060] The mixture of 15wt% HF and 10wt% hydrochloric acid in a 1:1 volume ratio was treated at 50°C for 3 hours, washed with water, dried and ready for use.

[0061] Everything else remains the same as in Example 4.

[0062] Example 6

[0063] (1) Preparation of a mixture containing active component elements

[0064] The raw materials used are shown in the table below:

[0065] Active component elements Specific raw materials used Usage Mo <![CDATA[Ammonium paramolybdate ((NH4)6Mo7O 24 )]]> 0.1mol Bi <![CDATA[Bismuth nitrate (Bi(NO3)3)]]> 0.28mol Co <![CDATA[Cobalt nitrate (Co(NO3)2)]]> 0.35mol Ca <![CDATA[Calcium chloride (CaCl2)]]> 1.4mol B <![CDATA[Ammonium borate (NH4HB4O7·3H2O)]]> 0.7mol

[0066] According to the above formula, ammonium molybdate, cobalt nitrate, calcium chloride and ammonium borate are dissolved in 3L of deionized water (50℃) to obtain solution A; 50g of 60wt% nitric acid and 200mL of deionized water are mixed evenly, and then bismuth nitrate is added and dissolved completely to obtain solution B; solution A and solution B are mixed evenly to obtain a mixed solution containing active component elements.

[0067] The active component in the prepared mixture has an elemental composition of MoBi. 0.4 Co 0.5 Ca2BO 7.6 The weight is 295.11g.

[0068] (4) Preparation of carrier

[0069] Weigh out 665.17g of SAPO-11 molecular sieve powder, 20.66g of graphite (3wt% of the carrier), and 2.75g of C. 60 Mix evenly (0.4 wt% of the carrier) to form the carrier.

[0070] (3) Impregnation and molding

[0071] The carrier is dispersed in the above-mentioned mixture containing active component elements, stirred and impregnated for 24 hours, and then the water is evaporated to a state suitable for extrusion molding, and extruded into spherical particles.

[0072] (4) Drying and roasting

[0073] The above spherical particles are dried at 100°C for 4 hours, and then calcined at 500°C for 6 hours.

[0074] The obtained catalyst, by weight, has the following composition: 30 wt% MoBi. 0.4 Co 0.5 Ca2BO 7.6 +70wt% carrier.

[0075] Comparative Example 1

[0076] The difference from Example 1 is that no graphite was added to the carrier.

[0077] Comparative Example 2

[0078] The difference from Example 1 is that C was not added to the carrier. 60 .

[0079] Test Example 1

[0080] 1500 ml of the catalyst obtained according to the methods of Examples 1-6 and Comparative Examples 1-2 was added to a stainless steel reactor with a diameter of 25 mm, and the mixture was subjected to an incubation period of 1800 h. -1 The space rate (STP) introduces a gas mixture containing 7v% propylene, 14v% oxygen, 25v% water vapor and 54v% nitrogen, and carries out the oxidation reaction at 310°C.

[0081] The specific experimental results are shown in Table 1, where:

[0082] Conversion rate (%) = Amount of propylene reacted / Original total amount of propylene * 100%

[0083] Yield (%) = Total molar amount of acrylic acid and acrolein / Original molar amount of propylene * 100%.

[0084] Table 1

[0085]

[0086]

[0087] Furthermore, the catalysts of Examples 1-6 and Comparative Examples 1-2 were continuously operated under the above conditions for 2000 h. Then, the propylene conversion rate, the yield of acrolein + acrylic acid, and the loss rates of molybdenum and bismuth were tested, and the appearance of the catalysts was observed. The specific results are shown in Table 2.

[0088] Table 2

[0089]

[0090] Therefore, it can be seen that after the catalyst of the present invention has been running continuously for 2000 hours, the propylene conversion rate and the yield of the target product have hardly changed, the loss rate of the main active elements Mo and Bi is very low, the performance is more stable, the service life is longer, and the catalyst replacement frequency of the production system can be reduced, saving consumable expenses.

[0091] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A catalyst for oxidizing olefins to prepare alkenals and olefinic acids, comprising a support and an active component supported on the support, characterized in that, The chemical formula of the active component is: MoBi a Co b Ca x B c O y Mo is molybdenum, Bi is bismuth, Co is cobalt, Ca is calcium, B is boron, and O is oxygen; a, b, c, x, and y are the molar ratios of each element; where 0.2≤a≤0.65, 0.3≤b≤1.0, 1.5≤x≤3, 0.4≤c≤1.5, and y is determined by the oxidation degree of the other elements and is the number of oxygen atoms required to satisfy the oxidation states of the other elements; The carrier is composed of molecular sieve powder, graphite, and C. 60 The mixture is used to obtain the molecular sieve powder, which is selected from one or more combinations of type A molecular sieve, type X molecular sieve, type Y molecular sieve, ZSM-5, SAPO-34, β molecular sieve, or SAPO-11; the amount of graphite added accounts for 2-8 wt% of the total weight of the carrier, and C 60 The amount added is 0.05 to 0.5 wt% of the total weight of the carrier.

2. The catalyst for oxidizing olefins to prepare enaldehydes and olefinic acids according to claim 1, characterized in that, The catalyst contains 10–35 wt% of the active component by weight.

3. The catalyst for oxidizing olefins to prepare alkenals and olefinic acids according to claim 1, characterized in that, The method for preparing the catalyst includes: preparing a mixture containing active component elements and the support; impregnating the support in the mixture of active component elements, then molding and calcining it to obtain the catalyst.

4. The catalyst for oxidizing olefins to prepare alkenals and olefinic acids according to claim 3, characterized in that, The molecular sieve powder is treated at 45-55°C for 2-5 hours in a mixed acid solution obtained by mixing 8-15 wt% HF and 10-20 wt% hydrochloric acid in a 1:1 volume ratio, washed with water, dried, and ready for use.

5. The catalyst for oxidizing olefins to prepare enal and olefinic acids according to claim 3, characterized in that, The calcination conditions are: calcination at 460℃~650℃ for 3~8 hours.

6. A method for preparing enal and olefinic acids by oxidizing olefins, characterized in that, The catalyst according to any one of claims 1-5 is used.

7. The method for preparing enal and olefinic acids by oxidizing olefins according to claim 6, characterized in that, The olefin is propylene, the aldehyde is acrolein, and the olefinic acid is acrylic acid.

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