High-selectivity tandem catalytic system for preparing methyl acetate from synthesis gas and preparation method of high-selectivity tandem catalytic system
By using a bifunctional catalyst and a tandem reaction system, the problems of low selectivity and numerous byproducts in the preparation of methyl acetate from syngas were solved, achieving the preparation of methyl acetate with high selectivity and low cost.
Patent Information
- Application Number
- CN202511692831.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-02-10
AI Technical Summary
Existing methods for preparing methyl acetate from syngas generate numerous byproducts, have low selectivity, and are difficult to control under reaction conditions, resulting in high production costs.
By employing a bifunctional catalyst and a tandem reaction system, and by combining a methanol synthesis catalyst and a methanol dehydration catalyst, and designing reasonable reaction conditions, a highly selective tandem catalytic preparation of methyl acetate was achieved.
It improves the selectivity and purity of methyl acetate, reduces the formation of byproducts, lowers production costs, and provides mild reaction conditions.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of compound preparation, and particularly relates to a high-selectivity series catalytic system for preparing methyl acetate from synthesis gas and a preparation method. BACKGROUND
[0002] Methyl acetate (MA), also known as methyl acetate, is a fatty acid ester with important application value in industry. It plays a key role in the fields of coatings, inks, adhesives, pharmaceutical and pesticide intermediates due to its excellent solubility. As a fast-drying solvent, methyl acetate can dissolve various resins such as polyurethane and phenolic resin, and has a higher flash point than acetone, which makes it gradually replace traditional solvents such as acetone, butanone and toluene. In the pharmaceutical industry and organic synthesis field, methyl acetate is an important raw material, which can be used to synthesize methyl methacrylate, and then produce polymethyl methacrylate. In addition, methyl acetate is also a main raw material for producing ethanol, which is obtained by hydrogenation reaction, and this process has high conversion rate and selectivity, and mild conditions.
[0003] At present, the main methods for synthesizing methyl acetate include methanol and acetic acid reaction rectification method, methanol dehydrogenation synthesis method, methanol carbonylation one-step method, homologation reaction of methyl formate and dimethyl ether carbonylation method. In recent years, the one-step method for synthesizing methyl acetate from synthesis gas has become a research hotspot in the field of catalysis due to its potential environmental friendliness and economic benefits. The dehydration of methanol to dimethyl ether is an acid catalytic reaction, and its activity is closely related to the acidity of the catalyst. Under strong acidic conditions, the dehydration reaction of methanol is violent, which may lead to the generation of a large amount of by-product methane. In addition, the matching of reaction conditions is also crucial. For example, the reaction temperature, pressure and space velocity of the dehydration of methanol to dimethyl ether will affect the conversion rate of methanol and the selectivity of dimethyl ether. Overcoming these challenges is the key to realizing the one-step method for synthesizing methyl acetate from synthesis gas. SUMMARY
[0004] The application aims to provide a high-selectivity series catalytic system for preparing methyl acetate from synthesis gas and a preparation method, which realizes high-selectivity synthesis of methyl acetate by using a bifunctional catalyst and a series reaction system, and helps to improve the purity of the product and reduce the generation of by-products.
[0005] To solve the above technical problems, the technical scheme adopted by the application is as follows: A preparation method of a high-selectivity series catalytic system for preparing methyl acetate from synthesis gas, comprising the following steps: S1, preparing a bifunctional catalyst: placing a methanol synthesis catalyst and a methanol dehydration catalyst in a mortar, grinding them thoroughly at a speed of 200-350 rpm for 10-20 min, and sieving them through a 60-100 mesh sieve to obtain the bifunctional catalyst; S2, the bifunctional catalyst obtained in step S1 is loaded into a fixed bed reactor A, and synthesis gas is introduced to heat the reaction to produce dimethyl ether; S3, the dimethyl ether obtained in step S2 is introduced into a fixed bed reactor B to heat the reaction to obtain methyl acetate.
[0006] Preferably, in step S1, the mass ratio of the methanol synthesis catalyst and the methanol dehydration catalyst is 2-3:1-1.5.
[0007] Preferably, the methanol synthesis catalyst has a preparation method comprising the following steps: A1, Cu(NO3)2 3H2O, Zn(NO3)2 6H2O and Al(NO3)3 9H2O is dissolved in deionized water to obtain a mixed solution A; A2, a 70% by mass phytic acid solution is mixed with deionized water to obtain a mixed solution B; A3, the mixed solution A is added dropwise to the mixed solution B at a speed of 3-5 , heated at a rate of 2-3 to 50-55 for 10-20 min, stirred at 400-1200 rpm for 1-2 h, and the reaction precipitate is collected, washed and centrifuged to obtain a solid mixture; A4, the solid mixture obtained in step A3 is heated to 360-400 at a rate of 4-6 under N2 atmosphere and calcined at constant temperature for 2-4 h to obtain a methanol synthesis catalyst.
[0008] Preferably, the methanol dehydration catalyst has a preparation method comprising the following steps: B1, octadecyltrimethoxysilane and a 60% by mass H2SO4 solution are mixed, the pH is adjusted to 1.2-1.8, C9H 21 AlO3 is added, and stirred at 300-600 rpm for 0.5-1 h to obtain a mixed solution C; B2, F127 (polyether F127) is mixed with a 60% by mass H2SO4 solution, the pH is adjusted to 1.2-1.8, and stirred at 300-600 rpm for 0.5-1 h to obtain a mixed solution D; B3, the mixed solution C is added dropwise to the mixed solution D at a speed of 3-5 , heated at a rate of 1-2 to 30-40 for 10-20 min, the reaction is transferred to an autoclave, and 110-150 Heat for 0.5-1.5 hours, filter, wash with distilled water, and heat to 60-70°C. Dry for 24-48 hours under N2 atmosphere at 4-6 degrees Celsius. Heating rate to 450-540 The catalyst was then calcined at a constant temperature for 4-8 hours to obtain a methanol dehydration catalyst.
[0009] Preferably, in step S2, the molar ratio of H2 to CO in the synthesis gas is 2-4:1-1.5.
[0010] Preferably, in step S2, the specific process conditions for the reaction are: a reaction temperature of 130-280°C. The reaction pressure is 1-10 MPa, and the reaction time is 1-3 h.
[0011] Preferably, the fixed-bed reactor A and the fixed-bed reactor B are connected in series via conduits.
[0012] Preferably, in step S3, the fixed-bed reactor B is filled with a dimethyl ether carbonyl catalyst.
[0013] Preferably, the dimethyl ether carbonyl catalyst comprises one or more of the following zeolite molecular sieves having an eight-membered ring topology: MOR, ETL, MFS, MTF, and EMT.
[0014] Preferably, in step S3, the reaction conditions are specifically: 3-5 The heating rate is such that the temperature can be increased to 300-420°C. The reaction pressure is 1-10 MPa, and the reaction time is 2-3 hours. Compared with the prior art, the present invention has the following advantages and technical effects: This invention discloses a highly selective tandem catalytic system and method for the preparation of methyl acetate from syngas. This system avoids the inhibitory effect of water generated during methanol dehydration on the carbonylation reaction of dimethyl ether, while effectively suppressing the side reactions of methanol and dimethyl ether converting to hydrocarbons, ensuring the highly selective synthesis of methyl acetate. Through carefully designed reaction conditions and catalyst ratios, this invention not only improves the selectivity of methyl acetate but also achieves efficient conversion under mild conditions, thereby reducing production costs and improving economic efficiency. The simplified process flow and reduced fixed investment and production costs provide a new technical route for the one-step production of methyl acetate from syngas, with broad market application prospects.
[0015] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation
[0016] The technical solution of the present invention will be further illustrated by the following embodiments.
[0017] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.
[0018] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.
[0019] Example 1 This embodiment provides a highly selective tandem catalytic system for the preparation of methyl acetate from syngas, and the preparation method includes the following steps: S1. Preparation of bifunctional catalyst: 20g of methanol synthesis catalyst and 10g of methanol dehydration catalyst were placed in a mortar and ground thoroughly at 300rpm for 15min. The mixture was then passed through a 100-mesh sieve to obtain the bifunctional catalyst. S2. The bifunctional catalyst obtained in step S1 is loaded into a fixed-bed reactor A, and syngas is introduced and pressurized to 5 MPa, wherein the molar ratio of H2 to CO in the syngas is 2:1. Dimethyl ether was obtained by heating for 1.5 hours. S3. The dimethyl ether obtained in step S2 is passed into fixed-bed reactor B (filled with MOR zeolite molecular sieve with an eight-membered ring topology). Fixed-bed reactors A and B are connected in series via conduits at a speed of 4... The heating rate, heated to 400 Methyl acetate was obtained by reacting at a pressure of 5 MPa for 2 hours.
[0020] The preparation method of the methanol synthesis catalyst includes the following steps: A1. 3.15g Cu(NO3)2 3H₂O, 2.01g Zn(NO₃)₂ 6H2O and 2.53g Al(NO3)3 9H2O was dissolved in 50 mL of deionized water to obtain mixed solution A; A2. Mix 13.5 mL of 70% phytic acid solution with 100 mL of deionized water to obtain mixed solution B; A3. Mix solution A with 3 Add it dropwise to mixed solution B at a rate of 3... Heating rate to 54 Keep for 15 minutes, stir at 600 rpm for 1.2 hours, collect the reaction precipitate, wash and centrifuge to obtain a solid mixture; A4. The solid mixture obtained in step A3 is subjected to a nitrogen atmosphere at 5°C. Heating to 400 at a rate The temperature was kept constant for 2 hours to obtain the methanol synthesis catalyst.
[0021] The preparation method of the methanol dehydration catalyst includes the following steps: B1. Mix 7.2 mL of octadecyltrimethoxysilane and 18 mL of 60% (w / w) H2SO4 solution, adjust the pH to 1.8, and add 1.578 g of C9H. 21 AlO3 was stirred at 600 rpm for 0.5 h to obtain mixed solution C; B2. Mix 3.0g of F127 with 50mL of 60% H2SO4 solution, adjust the pH to 1.8, and stir at 600rpm for 0.5h to obtain mixed solution D; B3. Mix solution C with 4 Add it dropwise to mixed solution D at a rate of 2 Heating rate to 40 Hold for 10 minutes, then transfer the reactants to a hydrothermal reactor at 120°C. Heat for 1 hour, filter, wash with distilled water, 60 Drying for 36 hours under N2 atmosphere at 5 Heating to 450 at a rate The catalyst was then calcined at a constant temperature for 8 hours to obtain a methanol dehydration catalyst.
[0022] Example 2 This embodiment provides a highly selective tandem catalytic system for the preparation of methyl acetate from syngas, and the preparation method includes the following steps: S1. Preparation of bifunctional catalyst: 30g of methanol synthesis catalyst and 12g of methanol dehydration catalyst were placed in a mortar and ground thoroughly at 300rpm for 15min. The mixture was then passed through a 100-mesh sieve to obtain the bifunctional catalyst. S2. The bifunctional catalyst obtained in step S1 is loaded into a fixed-bed reactor A, and syngas is introduced and pressurized to 5 MPa, wherein the molar ratio of H2 to CO in the syngas is 4:1.5. Dimethyl ether was obtained by heating for 1 hour. S3. The dimethyl ether obtained in step S2 is passed into fixed-bed reactor B (filled with EMT zeolite molecular sieve with an eight-membered ring topology). Fixed-bed reactors A and B are connected in series via conduits at a speed of 3... The heating rate, heated to 300 Methyl acetate was obtained by reacting at a pressure of 5 MPa for 3 hours.
[0023] The preparation methods for the methanol synthesis catalyst and the methanol dehydration catalyst are the same as in Example 1.
[0024] Example 3 This embodiment provides a highly selective tandem catalytic system for the preparation of methyl acetate from syngas, and the preparation method includes the following steps: S1. Preparation of bifunctional catalyst: 20g of methanol synthesis catalyst and 15g of methanol dehydration catalyst were placed in a mortar and ground thoroughly at 200rpm for 20min. The mixture was then passed through a 60-mesh sieve to obtain the bifunctional catalyst. S2. The bifunctional catalyst obtained in step S1 is loaded into a fixed-bed reactor A, and syngas is introduced and pressurized to 10 MPa, wherein the molar ratio of H2 to CO in the syngas is 2:1. Dimethyl ether was obtained by heating for 1 hour. S3. The dimethyl ether obtained in step S2 is passed into fixed-bed reactor B (filled with ETL zeolite molecular sieves with an eight-membered ring topology). Fixed-bed reactors A and B are connected in series via conduits at a speed of 5... The heating rate, heated to 420 Methyl acetate was obtained by reacting at a pressure of 10 MPa for 2 hours.
[0025] The preparation methods for the methanol synthesis catalyst and the methanol dehydration catalyst are the same as in Example 1.
[0026] Comparative Example 1 S1. Preparation of bifunctional catalyst: 20g Cu-ZnO and 10g ZSM-5 molecular sieve were placed in a mortar and ground thoroughly at 300rpm for 15min. The mixture was then passed through a 100-mesh sieve to obtain the bifunctional catalyst. S2. The bifunctional catalyst obtained in step S1 is loaded into a fixed-bed reactor A, and syngas is introduced, wherein the molar ratio of H2 to CO in the syngas is 2:1. The reactor is then subjected to a pressure of 5 MPa and a temperature of 150°C. Dimethyl ether was obtained by heating for 1.5 hours. S3. The dimethyl ether obtained in step S2 is passed into fixed-bed reactor B (filled with MOR zeolite molecular sieve with an eight-membered ring topology). Fixed-bed reactors A and B are connected in series via conduits at a speed of 4... The heating rate, heated to 400 Methyl acetate was obtained by reacting at a pressure of 5 MPa for 2 hours.
[0027] The above Examples 1-3 and Comparative Example 1 were subjected to online gas chromatography analysis of all components, and the results are shown in Table 1.
[0028] Table 1 Chromatographic Detection Results
[0029] Note: Others are all hydrocarbons except ethane.
[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a highly selective tandem catalytic system for the production of methyl acetate from syngas, characterized in that, Includes the following steps: S1. Preparation of bifunctional catalyst: The methanol synthesis catalyst and the methanol dehydration catalyst are placed in a mortar and ground thoroughly at 200-350 rpm for 10-20 min. The mixture is then passed through a 60-100 mesh sieve to obtain the bifunctional catalyst. S2. The bifunctional catalyst obtained in step S1 is loaded into a fixed-bed reactor A, syngas is introduced, and the reaction is heated to obtain dimethyl ether. S3. The dimethyl ether obtained in step S2 is introduced into a fixed-bed reactor B and heated to react, yielding methyl acetate.
2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of methanol synthesis catalyst to methanol dehydration catalyst is 2-3:1-1.
5.
3. The preparation method according to claim 1 or 2, characterized in that, The methanol synthesis catalyst is prepared by the following steps: A1. Cu(NO3)2 3H2O, Zn(NO3)2 6H2O and Al(NO3)3 9H2O dissolves in deionized water to obtain mixed solution A; A2. Mix a 70% phytic acid solution with deionized water to obtain mixed solution B; A3. Mix solution A with 3-5 Add it dropwise to mixed solution B at a rate of 2-3 times. Heating rate to 50-55 Keep for 10-20 minutes, stir at 400-1200 rpm for 1-2 hours, collect the reaction precipitate, wash and centrifuge to obtain a solid mixture; A4. The solid mixture obtained in step A3 is subjected to a nitrogen atmosphere at a temperature of 4-6... Heating rate to 360-400 The catalyst was then calcined at a constant temperature for 2-4 hours to obtain a methanol synthesis catalyst.
4. The preparation method according to claim 1 or 2, characterized in that, The methanol dehydration catalyst is prepared by the following steps: B1. Mix octadecyltrimethoxysilane and a 60% (w / w) H₂SO₄ solution, adjust the pH to 1.2-1.8, and add C9H₂O. 21 AlO3 was stirred at 300-600 rpm for 0.5-1 h to obtain a mixed solution C; B2. Mix F127 with a 60% H2SO4 solution, adjust the pH to 1.2-1.8, and stir at 300-600 rpm for 0.5-1 h to obtain mixed solution D; B3. Mix solution C with 3-5 Add the solution dropwise to the mixed solution D at a rate of 1-2 drops. Heating rate to 30-40 Maintain for 10-20 minutes, then transfer the reactants to a hydrothermal reactor at 110-150°C. Heat for 0.5-1.5 hours, filter, wash with distilled water, and heat to 60-70°C. Dry for 24-48 hours under N2 atmosphere at 4-6 degrees Celsius. Heating rate to 450-540 The catalyst was then calcined at a constant temperature for 4-8 hours to obtain a methanol dehydration catalyst.
5. The preparation method according to claim 1, characterized in that, In step S2, the molar ratio of H2 to CO in the synthesis gas is 2-4:1-1.
5.
6. The preparation method according to claim 1, characterized in that, In step S2, the specific process conditions for the reaction are: a reaction temperature of 130-280°C. The reaction pressure is 1-10 MPa, and the reaction time is 1-3 h.
7. The preparation method according to claim 1, characterized in that, The fixed-bed reactor A and fixed-bed reactor B are connected in series via conduits.
8. The preparation method according to claim 1, characterized in that, In step S3, the fixed-bed reactor B is filled with a dimethyl ether carbonyl catalyst.
9. The preparation method according to claim 8, characterized in that, The dimethyl ether carbonyl catalyst includes one or more of the following zeolite molecular sieves: MOR, ETL, MFS, MTF, and EMT, which have an eight-membered ring topology.
10. The preparation method according to claim 1, characterized in that, In step S3, the specific reaction conditions are: 3-5 The heating rate is such that the temperature can be increased to 300-420°C. The reaction pressure is 1-10 MPa, and the reaction time is 2-3 h.