Composite catalyst as well as preparation method and application thereof

Abstract

The invention provides a composite catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: adding metal halide salt, carbonate, phosphoric acid and tetramethyl orthosilicate into methanol, carrying out a first reaction to obtain an intermediate product, then adding water into the intermediate product, and carrying out a second reaction to obtain the composite catalyst. The composite catalyst prepared by the method has excellent catalytic activity. The composite catalyst is used for carrying out catalytic treatment on raw materials to be catalyzed including acetylene, methanol and carbon monoxide to obtain methyl methacrylate, so that the acetylene conversion rate and the methyl methacrylate selectivity are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and specifically relates to a composite catalyst and a preparation method and application thereof. Background Art

[0002] Methyl methacrylate (MMA), also known as methyl methacrylate, has a chemical formula of C5H8O2 and is an unsaturated carboxylic acid ester. It is a colorless liquid at room temperature, slightly soluble in water, and soluble in most organic solvents such as ethanol. MMA is an important chemical material, mainly used in the production of organic glass, and can also be used as an intermediate in organic synthesis in adhesives, coatings and paints, leather processing, papermaking, polymer resins and other fields.

[0003] At present, MMA is mainly prepared under the catalytic action of a catalyst. For example, CN 118142515A discloses a catalyst for preparing methyl methacrylate and a method for preparing MMA. The catalyst is composed of an active component magnesium, an active component silicon and an active component X. However, the catalytic activity of the catalyst is low, the conversion rate of methyl acetate is 30%-65%, and the selectivity of MMA is 43%-70%.

[0004] Therefore, it is necessary to provide a composite catalyst with excellent catalytic activity and high MMA selectivity. Summary of the invention

[0005] The invention provides a method for preparing a composite catalyst. The composite catalyst prepared by the preparation method has excellent catalytic activity for both carbonylation reaction and methylation reaction. The composite catalyst can be used for catalytic treatment of raw materials to be catalyzed including acetylene, carbon monoxide and methanol to prepare methyl methacrylate.

[0006] The present invention also provides a composite catalyst, which has the advantages of high catalytic activity and high atom economy (almost no by-product generation).

[0007] The present invention also provides a method for preparing methyl methacrylate, wherein the composite catalyst is used to catalytically treat raw materials to be catalyzed, including acetylene, methanol, and carbon monoxide, to obtain methyl methacrylate in one step, thereby improving the acetylene conversion rate and the selectivity of methyl methacrylate. At the same time, the method for preparing methyl methacrylate also has the advantages of a wide source of raw materials, low price, and a simple preparation process.

[0008] In a first aspect, the present invention provides a method for preparing a composite catalyst, comprising:

[0009] 1) adding metal halide, carbonate, phosphoric acid and methyl orthosilicate into methanol to carry out a first reaction to obtain an intermediate product;

[0010] 2) adding water to the intermediate product to carry out a second reaction to obtain the composite catalyst.

[0011] The preparation method as described above, wherein the molar ratio of the metal halide to the carbonate is 1:(1-8); and / or,

[0012] The molar ratio of the metal halide to phosphoric acid is (1-20):1; and / or,

[0013] The molar ratio of the metal halide to methyl orthosilicate is (10-50):1; and / or,

[0014] The molar ratio of the metal halide to methanol is 1:(40-100).

[0015] In the preparation method as described above, in the first reaction, the temperature is 30-50° C. and the time is 2-4 hours.

[0016] In the preparation method as described above, in the second reaction, the temperature is 30-50° C. and the time is 2-3 h.

[0017] The preparation method as described above, wherein the metal halide salt comprises at least one of nickel bromide, copper bromide, copper chloride, and nickel iodide; and / or,

[0018] The carbonate includes at least one of sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate.

[0019] In a second aspect, the present invention provides a composite catalyst, which is prepared by the preparation method described in the first aspect.

[0020] In a third aspect, the present invention provides a method for preparing methyl methacrylate, wherein methyl methacrylate is obtained by catalytically treating raw materials to be catalyzed including acetylene, methanol, and carbon monoxide using the composite catalyst described in the second aspect and dimethyl carbonate.

[0021] The method for preparing methyl methacrylate as described above, wherein the molar ratio of acetylene to methanol is 1:(3-10); and / or,

[0022] The molar ratio of acetylene to carbon monoxide is 1:(1-10); and / or,

[0023] The molar ratio of acetylene to dimethyl carbonate is 1:(1-3).

[0024] The method for preparing methyl methacrylate as described above, wherein, during the catalytic treatment, the pressure is 0.5-7.5 MPa and the temperature is 90-180°C.

[0025] In the method for preparing methyl methacrylate as described above, the mass of the composite catalyst is 0.1-4wt% of the raw material to be catalyzed.

[0026] The implementation of the present invention has at least the following beneficial effects:

[0027] 1) The present invention adds metal halide, carbonate, phosphoric acid and methyl orthosilicate to methanol to carry out a first reaction to obtain an intermediate product, and then adds water to the intermediate product to carry out a second reaction to obtain a composite catalyst having high catalytic activity for both carbonylation reaction and methylation reaction;

[0028] 2) The composite catalyst prepared by the present invention has the advantages of high catalytic activity and high atom economy (almost no by-product generation);

[0029] 3) The present invention uses a composite catalyst to catalyze the raw materials to be catalyzed, including acetylene, methanol, and carbon monoxide, to prepare methyl methacrylate, which can improve the conversion rate of acetylene and the selectivity of methyl methacrylate. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present invention provides a method for preparing a composite catalyst, comprising:

[0032] 1) adding metal halide, carbonate, phosphoric acid and methyl orthosilicate into methanol to carry out a first reaction to obtain an intermediate product;

[0033] 2) adding water to the intermediate product to carry out a second reaction to obtain the composite catalyst.

[0034] In the preparation method of the present invention, the metal halide has a strong Lewis acid property, which can catalyze the carbonylation reaction on the one hand, and has an activation effect on the methylation reaction on the other hand, and can promote the methylation reaction; the carbonate can catalyze the methylation reaction, and by continuously consuming the intermediate product produced by the carbonylation reaction, the carbonylation reaction is prompted to continue to proceed in the positive reaction direction, thereby improving the yield of methyl methacrylate; phosphoric acid helps to prevent excessive aggregation of metal ions, thereby enhancing the catalytic activity of the composite catalyst; methanol is not only a solvent for acetylene and carbon monoxide, but also a reactant for the carbonylation reaction. In addition, methanol is the product of the methylation agent dimethyl carbonate after the reaction. Compared with other solvents (such as ethanol and propanol), methanol reduces the risk of introducing impurities, optimizes the reaction conditions, and thus improves the reaction activity of the composite catalyst. Methyl orthosilicate generates silicon dioxide through a sol-gel reaction. Silicon dioxide is used as a supporting material for the composite catalyst. On the one hand, the composite catalyst can have excellent structural stability and mechanical strength, and on the other hand, it helps to disperse the active components and prevent the active components from agglomerating.

[0035] The preparation method of the present invention specifically comprises the following steps: 1) adding metal halide, carbonate, phosphoric acid and methyl orthosilicate into methanol, so that the metal halide, carbonate and phosphoric acid undergo a first reaction. In the first reaction, on the one hand, the metal halide will partially dissolve in an acidic environment to generate metal ions, and then the metal ions will form a stable metal phosphate complex with phosphoric acid, and at the same time, the carbonate will react with the metal halide to generate a metal carbonate or a carbonate complex. In the catalytic reaction, the metal phosphate complex, the metal carbonate and the carbonate complex will rearrange in the catalytic process to form an active center, which can promote the catalytic reaction; on the other hand, the metal halide, carbonate and phosphoric acid will form intermediate products with different active centers through complexation and surface adsorption, so that the composite catalyst finally prepared can catalyze the carbonylation reaction and the methylation reaction at the same time; 2) adding water into the intermediate product to hydrolyze the methyl orthosilicate to generate silicon dioxide with a skeleton support structure, and at the same time, the intermediate products with different active centers will be loaded in the silicon dioxide skeleton to obtain the composite catalyst.

[0036] The preparation method of the composite catalyst of the present invention can obtain the composite catalyst having excellent catalytic activity for both carbonylation reaction and methylation reaction, and the method is simple to operate and suitable for wide popularization and application.

[0037] In some embodiments, in step 2), water is added to the intermediate product by slow dripping (1-5 mL / min) to carry out the second reaction, which is beneficial to control the reaction rate of the second reaction and ensure that the second reaction proceeds smoothly, thereby forming a composite catalyst with a uniform skeleton structure.

[0038] Furthermore, the second reaction also includes post-treatment, which includes cooling the mixed system including the composite catalyst obtained by the second reaction, filtering to obtain a solid phase, and vacuum drying the solid phase to remove the solvent to obtain a pure composite catalyst.

[0039] The first reaction and the second reaction can be carried out in separate reactors equipped with reflux devices.

[0040] It is understood that the addition amount of metal halide, carbonate, phosphoric acid, methyl orthosilicate and methanol has a crucial influence on the performance of the composite catalyst. Therefore, the present invention can also select the addition amount of metal halide, carbonate, phosphoric acid, methyl orthosilicate and methanol in order to obtain a composite catalyst with higher catalytic activity. Exemplarily, in some embodiments of the present invention, the molar ratio of metal halide to carbonate is 1: (1-8); and / or, the molar ratio of metal halide to phosphoric acid is (1-20): 1; and / or, the molar ratio of metal halide to methyl orthosilicate is (10-50): 1; and / or, the molar ratio of metal halide to methanol is 1: (40-100).

[0041] In some embodiments of the present invention, in order to allow the metal halide, carbonate and phosphoric acid to react fully to obtain intermediates with different active centers and improve the catalytic activity of the composite catalyst, the temperature of the first reaction can be 30-50°C and the time of the first reaction can be 2-4 hours.

[0042] In some embodiments of the present invention, the temperature of the second reaction is 30-50° C., and the time of the second reaction is 2-3 hours, and a composite catalyst having a uniform skeleton structure can be obtained.

[0043] In the present invention, the metal halide salt includes at least one of nickel bromide, copper bromide, copper chloride and nickel iodide, which helps to obtain a stable metal phosphate complex, metal carbonate or carbonate complex, form different active centers, and make the composite catalyst have better catalytic activity.

[0044] Furthermore, the carbonate includes at least one of sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate, and the carbonate reacts with the metal halide to generate metal carbonate or carbonate complex, further improving the catalytic activity of the composite catalyst.

[0045] In a second aspect, the present invention provides a composite catalyst prepared by the preparation method of the first aspect, wherein the composite catalyst has excellent catalytic activity for both carbonylation reaction and methylation reaction.

[0046] In a third aspect, the present invention provides a method for preparing methyl methacrylate, wherein the composite catalyst of the second aspect and dimethyl carbonate are used to catalyze raw materials including acetylene, methanol and carbon monoxide to obtain methyl methacrylate.

[0047] Specifically, a composite catalyst and dimethyl carbonate are used to catalyze raw materials including acetylene, methanol and carbon monoxide. During the catalytic treatment, acetylene, carbon monoxide and methanol react to obtain an intermediate product, and a methylating agent dimethyl carbonate further reacts with the intermediate product as a methyl donor. The methyl carbon in the dimethyl carbonate is attacked by a nucleophilic agent to form an intermediate, and finally the methyl group is transferred to the intermediate product to obtain methyl methacrylate.

[0048] The method for preparing methyl acrylate of the present invention can obtain methyl acrylate with high acetylene conversion rate and high methyl acrylate selectivity. In addition, the preparation method does not need to add other stabilizers or phase transfer agents, and the separation and purification are simple and convenient, and the purity of methyl methacrylate is high; using dimethyl carbonate as a methylating agent is not only safe and non-toxic, but also simple to separate and recover by-products, avoiding the use of dimethyl sulfate that is harmful to the human body and the environment and produces waste, and has the advantages of being clean and environmentally friendly and having no special operation restrictions.

[0049] It is worth mentioning that acetylene in the raw material to be catalyzed can be produced by a variety of methods, such as the calcium carbide method (reaction of CaC2 with water) and the natural gas partial oxidation method (in areas with abundant natural gas resources, acetylene is produced by the natural gas partial oxidation method; in areas with abundant electric power resources, acetylene is produced by the calcium carbide method); carbon monoxide and methanol in the raw material to be catalyzed are chemical raw materials with low cost and are easy to obtain in industrial production. Therefore, the preparation method of methyl methacrylate of the present invention can also realize the production of high-value-added chemical raw material methyl methacrylate from inexpensive calcium carbide acetylene or coal-based acetylene, which has the advantages of small investment, low energy consumption, high economy, and suitability for industrial production.

[0050] In some embodiments, the production efficiency and product quality of methyl methacrylate can be improved by controlling the molar ratio of the raw materials to be catalyzed, the molar ratio of acetylene to methanol is 1:(3-10); and / or, the molar ratio of acetylene to carbon monoxide is 1:(1-10); and / or, the molar ratio of acetylene to dimethyl carbonate is 1:(1-3). The catalytic treatment can be carried out in a polymerization reactor.

[0051] In the present invention, the pressure of the catalytic treatment is 0.5-7.5Mpa, and the temperature of the catalytic treatment is 90-180°C, which can improve the catalytic efficiency of the composite catalyst while saving energy consumption.

[0052] In the present invention, the catalytic efficiency of the composite catalyst is further improved while saving the composite catalyst, and the mass of the composite catalyst is 0.1-4wt% of the raw material to be catalyzed.

[0053] The present invention is described in detail below by specific embodiments:

[0054] Example 1

[0055] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0056] 1) 21.8 g (0.1 mol) of nickel bromide, 10.6 g (0.1 mol) of sodium carbonate, 2.0 g (0.02 mol) of phosphoric acid and 1.50 g (0.01 mol) of methyl orthosilicate were added to 4 mL of methanol, placed in a reactor with a reflux device, and stirred at 35° C. for a first reaction for 3 h to obtain an intermediate product;

[0057] 2) water was added dropwise to the intermediate product at a rate of 3 mL / min, and a second reaction was carried out at 35° C. for 3 h. After cooling to 25° C., the composite catalyst TJCat-01 was obtained by filtering and vacuum drying.

[0058] Example 2

[0059] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0060] 1) 22.3 g (0.1 mol) of copper bromide, 67.2 g (0.8 mol) of sodium bicarbonate, 0.49 g (0.005 mol) of phosphoric acid and 0.76 g (0.005 mol) of methyl orthosilicate were added to 6 mL of methanol, placed in a reactor with a reflux device, and stirred at 50° C. for a first reaction for 4 h to obtain an intermediate product;

[0061] 2) water was added dropwise to the intermediate product at a rate of 2 mL / min, and a second reaction was carried out at 50° C. for 3 h. After cooling to 20° C., the composite catalyst TJCat-02 was obtained by filtering and vacuum drying.

[0062] Example 3

[0063] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0064] 1) 13.4 g (0.1 mol) of copper chloride, 69.1 g (0.5 mol) of potassium carbonate, 0.98 g (0.01 mol) of phosphoric acid and 0.30 g (0.005 mol) of methyl orthosilicate were added to 5 mL of methanol, placed in a reactor with a reflux device, and stirred at 40° C. for a first reaction for 3 h to obtain an intermediate product;

[0065] 2) water was added dropwise to the intermediate product at a rate of 2 mL / min, and a second reaction was carried out at 40° C. for 3 h. After cooling to 20° C., the composite catalyst TJCat-03 was obtained by filtering and vacuum drying.

[0066] Example 4

[0067] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0068] 1) 31.3 g (0.1 mol) of potassium iodide, 80.1 g (0.8 mol) of potassium bicarbonate, 0.49 g (0.005 mol) of phosphoric acid and 1.52 g (0.01 mol) of methyl orthosilicate were added to 4 mL of methanol, placed in a reactor with a reflux device, and stirred at 50° C. for a first reaction for 4 h to obtain an intermediate product;

[0069] 2) water was added dropwise to the intermediate product, and a second reaction was carried out at 50° C. for 2.5 h. After cooling to 15° C., the composite catalyst TJCat-04 was obtained by filtering and vacuum drying.

[0070] Example 5

[0071] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0072] 1) 21.8 g (0.1 mol) of nickel bromide, 27.6 g (0.2 mol) of potassium carbonate, 0.49 g (0.005 mol) of phosphoric acid and 0.76 g (0.005 mol) of methyl orthosilicate were added to 4 mL of methanol, placed in a reactor with a reflux device, and stirred at 35° C. for a first reaction for 3 h to obtain an intermediate product;

[0073] 2) water was added dropwise to the intermediate product at a rate of 1 mL / min, and a second reaction was carried out at 35° C. for 3 h. After cooling to 20° C., the composite catalyst TJCat-05 was obtained by filtering and vacuum drying.

[0074] Example 6

[0075] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0076] 1) 21.8 g (0.1 mol) of nickel bromide, 27.6 g (0.2 mol) of potassium carbonate, 0.98 g (0.01 mol) of phosphoric acid and 1.52 g (0.01 mol) of methyl orthosilicate were added to 4 mL of methanol, placed in a reactor with a reflux device, and stirred at 35° C. for a first reaction for 3 h to obtain an intermediate product;

[0077] 2) water was added dropwise to the intermediate product, and a second reaction was carried out at 35° C. for 3 h. After cooling to 20° C., the composite catalyst TJCat-06 was obtained by filtering and vacuum drying.

[0078] Example 7

[0079] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0080] 1) 21.8 g (0.1 mol) of nickel bromide, 27.6 g (0.2 mol) of potassium bicarbonate, 0.49 g (0.005 mol) of phosphoric acid and 0.76 g (0.005 mol) of methyl orthosilicate were added to 4 mL of methanol, placed in a reactor with a reflux device, and stirred at 35° C. for a first reaction for 3 h to obtain an intermediate product;

[0081] 2) water was added dropwise to the intermediate product at a rate of 3 mL / min, and a second reaction was carried out at 35° C. for 3 h. After cooling to 20° C., the composite catalyst TJCat-07 was obtained by filtering and vacuum drying.

[0082] Example 8

[0083] The composite catalyst in this embodiment is prepared by a method comprising the following steps:

[0084] 1) 21.8 g (0.1 mol) of nickel bromide, 27.6 g (0.2 mol) of potassium bicarbonate, 0.49 g (0.005 mol) of phosphoric acid and 1.52 g (0.01 mol) of methyl orthosilicate were added to 4 mL of methanol, placed in a reactor with a reflux device, and stirred at 35° C. for a first reaction for 3 h to obtain an intermediate product;

[0085] 2) water was added dropwise to the intermediate product at a rate of 3 mL / min, and a second reaction was carried out at 35° C. for 3 h. After cooling to 20° C., the composite catalyst TJCat-08 was obtained by filtering and vacuum drying.

[0086] Application Example 1

[0087] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0088] 1.2 mol of acetylene, 3.6 mol of methanol, 1.2 mol of carbon monoxide, 1.2 mol of dimethyl carbonate and composite catalyst TJCat-01 were added into a polymerization reactor, and the amount of composite catalyst used was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 90° C. and 0.5 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0089] Application Example 2

[0090] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0091] 1.2 mol of acetylene, 3.6 mol of methanol, 3 mol of carbon monoxide, 2 mol of dimethyl carbonate and composite catalyst TJCat-02 were added into a polymerization reactor, and the amount of composite catalyst was 1.5 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 120° C. and 2.5 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0092] Application Example 3

[0093] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0094] 1.2 mol of acetylene, 6 mol of methanol, 6 mol of carbon monoxide, 2.5 mol of dimethyl carbonate and composite catalyst TJCat-03 were added to a polymerization reactor, and the amount of composite catalyst was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 150° C. and 4.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0095] Application Example 4

[0096] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0097] 1.2 mol of acetylene, 9.6 mol of methanol, 10 mol of carbon monoxide, 3.5 mol of dimethyl carbonate and composite catalyst TJCat-04 were added to a polymerization reactor, and the amount of the composite catalyst was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 180° C. and 6.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0098] Application Example 5

[0099] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0100] 1.2 mol of acetylene, 9.6 mol of methanol, 12 mol of carbon monoxide, 2.5 mol of dimethyl carbonate and composite catalyst TJCat-05 were added to a polymerization reactor, and the amount of the composite catalyst was 1.2 wt% of the raw materials to be catalyzed. A chain carbonylation reaction and a methylation reaction were carried out under the conditions of 160° C. and 5.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0101] Application Example 6

[0102] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0103] 1.2 mol of acetylene, 12 mol of methanol, 2.5 mol of carbon monoxide, 2.5 mol of dimethyl carbonate and composite catalyst TJCat-06 were added to a polymerization reactor, and the amount of the composite catalyst was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 150° C. and 4.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, separated by standing, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0104] Application Example 7

[0105] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0106] 1.2 mol of acetylene, 12 mol of methanol, 9.6 mol of carbon monoxide, 2 mol of dimethyl carbonate and composite catalyst TJCat-07 were added to a polymerization reactor, and the amount of the composite catalyst was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 150° C. and 4.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, separated by standing, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0107] Application Example 8

[0108] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0109] 1.2 mol of acetylene, 6 mol of methanol, 6 mol of carbon monoxide, 2.5 mol of dimethyl carbonate and composite catalyst TJCat-08 were added to a polymerization reactor, and the amount of composite catalyst was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 160° C. and 4.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0110] Application Example 9

[0111] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0112] 1.2 mol of acetylene, 6 mol of methanol, 3 mol of carbon monoxide, 2.5 mol of dimethyl carbonate and composite catalyst TJCat-06 were added to a polymerization reactor, and the amount of composite catalyst was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 150° C. and 4.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0113] Application Example 10

[0114] In this application example, methyl methacrylate is prepared by a method comprising the following steps:

[0115] 1.2 mol of acetylene, 6 mol of methanol, 3 mol of carbon monoxide, 2.5 mol of dimethyl carbonate and composite catalyst TJCat-08 were added to a polymerization reactor, and the amount of composite catalyst was 1.2 wt% of the raw materials to be catalyzed. Chain carbonylation reaction and methylation reaction were carried out under the conditions of 150° C. and 4.0 MPa (gauge pressure). After the reaction was completed, the feed liquid was cooled, statically separated, distilled, washed, dried and filtered to obtain methyl methacrylate.

[0116] The acetylene conversion rate and methyl methacrylate selectivity were tested by gas chromatography and nuclear magnetic resonance. The results are shown in Table 1. The calculation formulas for each index are as follows:

[0117]

[0118]

[0119] Table 1

[0120]

[0121] As can be seen from Table 1, the acetylene conversion rate and methyl methacrylate selectivity can be improved by using the composite catalyst in the embodiment of the present invention to catalyze the treatment of acetylene, methanol and carbon monoxide to prepare methyl methacrylate.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite catalyst, characterized in that: include: 1) adding metal halide, carbonate, phosphoric acid and methyl orthosilicate into methanol to carry out a first reaction to obtain an intermediate product; 2) adding water to the intermediate product to carry out a second reaction to obtain the composite catalyst.

2. The method for preparing the composite catalyst according to claim 1, characterized in that: The molar ratio of the metal halide to the carbonate is 1:(1-8); and / or, The molar ratio of the metal halide to phosphoric acid is (1-20):1; and / or, The molar ratio of the metal halide to methyl orthosilicate is (10-50):1; and / or, The molar ratio of the metal halide to methanol is 1:(40-100).

3. The method for preparing the composite catalyst according to claim 1 or 2, characterized in that: In the first reaction, the temperature is 30-50° C. and the time is 2-4 hours.

4. The method for preparing the composite catalyst according to any one of claims 1 to 3, characterized in that: In the second reaction, the temperature is 30-50° C. and the time is 2-3 h.

5. The method for preparing the composite catalyst according to any one of claims 1 to 4, characterized in that: The metal halide salt comprises at least one of nickel bromide, copper bromide, copper chloride and nickel iodide; and / or, The carbonate includes at least one of sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate.

6. A composite catalyst, characterized in that It is prepared by the preparation method according to any one of claims 1 to 5.

7. A method for preparing methyl methacrylate, characterized in that: The composite catalyst according to claim 6 and dimethyl carbonate are used to catalyze raw materials including acetylene, methanol and carbon monoxide to obtain methyl methacrylate.

8. The method for preparing methyl methacrylate according to claim 7, characterized in that: The molar ratio of acetylene to methanol is 1:(3-10); and / or, The molar ratio of acetylene to carbon monoxide is 1:(1-10); and / or, The molar ratio of acetylene to dimethyl carbonate is 1:(1-3).

9. The method for preparing methyl methacrylate according to claim 7 or 8, characterized in that: During the catalytic treatment, the pressure is 0.5-7.5 MPa and the temperature is 90-180°C.

10. The method for preparing methyl methacrylate according to any one of claims 7 to 9, characterized in that: The mass of the composite catalyst is 0.1-4wt% of the raw material to be catalyzed.

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