Modification method and application of dimethyl ether carbonylation catalyst
Through the gas-phase modified mordenite molecular sieve of imidazole organics, the problems of low catalytic activity and poor stability in dimethyl ether carbonylation catalysis were solved, and efficient catalytic effect and long-term stability were achieved under mild conditions.
Patent Information
- Application Number
- CN202411722261.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-03-18
AI Technical Summary
Mordenite (MOR) has problems such as low catalytic activity, poor stability and limited active sites in dimethyl ether carbonylation catalysis, which limits its promotion in commercial applications.
The stability of the catalyst is significantly improved by gas-phase modified mordenite molecular sieve through imidazole organics. The specific steps include placing the H-MOR molecular sieve in the reactor, passing saturated vapor containing imidazole organic matter, performing adsorption and purging treatment, and obtaining the modified H-MOR molecular sieve.
The modified H-MOR molecular sieve can effectively catalyze the carbonylation of dimethyl ether under mild conditions to prepare methyl acetate. The dimethyl ether conversion rate reaches 70-90%, the selectivity of methyl acetate is greater than 99%, and the activity of the catalyst remains stable after 500 hours of stable reaction operation.
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Abstract
Description
Technical Field
[0001] The present application relates to a modification method of a dimethyl ether carbonylation catalyst and application thereof, belonging to the field of industrial catalysis. Background Art
[0002] At present, people are vigorously developing renewable energy such as solar energy, wind energy, and hydropower. Although the development of renewable energy has achieved certain results, fossil energy consumption still occupies an important position in my country's energy structure consumption. Therefore, fossil energy will continue to play an important role in energy consumption. Among them, the preparation of important basic chemicals using coal as raw material can not only reduce the degree of dependence on oil, but also has immeasurable significance for achieving long-term stable development of my country's economy and society. As a world-recognized environmentally friendly clean fuel and excellent gasoline additive, ethanol has long received great attention. The Dalian Institute of Chemical Physics has developed a new process route for synthesizing ethanol from coal-based synthesis gas through carbonylation and hydrogenation. This route is centered on dimethyl ether carbonylation and uses non-precious metal catalysts to directly produce anhydrous ethanol. It is a unique new environmentally friendly process. At present, mordenite (MOR) molecular sieve has the best catalytic performance for dimethyl ether carbonylation. Although mordenite (MOR) shows good dimethyl ether carbonylation activity, it still has problems such as low catalytic activity, poor stability, and limited active sites, which limits its promotion in commercial applications. Summary of the invention
[0003] According to the first aspect of the present application, a method for modifying a dimethyl ether carbonylation catalyst is provided. The method utilizes imidazole organic matter to modify mordenite molecular sieve in gas phase, thereby significantly improving the stability of the catalyst.
[0004] A method for modifying a dimethyl ether carbonylation catalyst, the modification method comprising the following steps:
[0005] The H-MOR molecular sieve is placed in a reactor, and saturated vapor containing imidazole organic matter is introduced until adsorption is saturated to obtain a modified H-MOR molecular sieve;
[0006] The imidazole organic compound is selected from at least one of 2-methylimidazole, 4-methylimidazole, 1,2-methylimidazole, 2,4-methylimidazole, 2-ethylimidazole, 4-ethylimidazole, 1,2-ethylimidazole and 2,4-ethylimidazole.
[0007] Optionally, the H-MOR molecular sieve is placed in a reactor, heated to 200-400° C., gas is introduced, and the treatment is carried out for 1-5 hours, and then saturated steam containing imidazole organic matter is introduced;
[0008] The gas is selected from at least one of He, N2, argon and air.
[0009] Optionally, the saturated vapor of the imidazole organic compound is introduced by a gas;
[0010] The gas is selected from at least one of He, N2, argon and air.
[0011] Optionally, the introducing saturated steam containing imidazole organic matter comprises:
[0012] The solid of the imidazole organic compound is heated and liquefied, and then the saturated vapor of the imidazole organic compound is introduced through the gas;
[0013] The gas is selected from at least one of He, N2, argon and air.
[0014] Optionally, the heating temperature is 200-400°C.
[0015] Optionally, the adsorption temperature is 300-450°C.
[0016] Optionally, the adsorption time is 1-24 hours.
[0017] Optionally, after adsorption saturation, gas is introduced for purging for 1-5 hours to obtain a modified H-MOR molecular sieve;
[0018] The gas is selected from at least one of He, N2, argon and air.
[0019] Optionally, the H-MOR molecular sieve has a silicon to aluminum ratio of 5-50.
[0020] As a preferred embodiment, the modification method comprises:
[0021] The H-type mordenite is loaded into a reactor, and pre-treated and modified under preset conditions to obtain modified H-type mordenite;
[0022] The pre-conditions include:
[0023] The reactor pretreatment temperature is 200-400°C, and the treatment is carried out under He, N2, argon or dry air atmosphere for 1-5 hours;
[0024] The activator is filled with solid imidazole organic matter, which is heated to 200-400°C for liquefaction, and saturated vapor is carried by He, N2, argon or dry air into the reactor for adsorption for 1-24 hours; then, He, N2, argon or dry air is purged at this temperature for 1-5 hours to form saturated adsorbed H-type mordenite.
[0025] According to a second aspect of the present application, a method for preparing methyl acetate by carbonylation of dimethyl ether is provided. The method uses the H-MOR molecular sieve obtained by the above-mentioned modification method as a catalyst, and can catalyze the carbonylation of dimethyl ether to prepare methyl acetate under mild conditions. The conversion rate of dimethyl ether is 70-90%, the selectivity of methyl acetate is greater than 99%, and the activity of the catalyst remains stable after the reaction is stably operated for 500 hours.
[0026] A method for preparing methyl acetate by carbonylation of dimethyl ether, wherein a raw gas containing dimethyl ether and carbon monoxide is introduced into a reactor, contacted with a catalyst, and reacted to obtain methyl acetate;
[0027] The catalyst is selected from the H-MOR molecular sieve obtained by the modification method described above.
[0028] Optionally, the reaction conditions are: the molar ratio of dimethyl ether to carbon monoxide is 1:1-50, and the total reaction space velocity is 1000-2000h -1 , temperature is 200~280℃, pressure is 2~8MPa.
[0029] Optionally, the reaction conditions are: the molar ratio of dimethyl ether to carbon monoxide is 1:1-10, and the total reaction space velocity is 1500-2000h -1 , temperature is 210~250℃, and pressure is 2~5MPa.
[0030] The beneficial effects of this application include:
[0031] The modification method of the dimethyl ether carbonylation catalyst provided in the present application uses imidazole organic matter to modify the mordenite molecular sieve in the gas phase, which significantly improves the stability of the catalyst. The H-MOR molecular sieve obtained by the modification method can be used as a catalyst to catalyze the carbonylation of dimethyl ether to produce methyl acetate under mild conditions. The dimethyl ether conversion rate is 70-90%, the selectivity of methyl acetate is greater than 99%, and the activity of the catalyst remains stable after the reaction is stably operated for 500 hours. DETAILED DESCRIPTION
[0032] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.
[0033] Unless otherwise specified, the raw materials and catalysts in the examples of this application were purchased through commercial channels.
[0034] Unless otherwise specified, conventional methods were used for testing and instrument settings were those recommended by the manufacturer.
[0035] The silicon-aluminum ratio of H-MOR molecular sieve is 19.
[0036] The analysis method in the examples of this application is as follows:
[0037] Relative crystallinity analysis of the modified H-MOR molecular sieve: X-ray diffractometer (XRD) was used for analysis, SmartLab SE X-ray diffractometer of Rigaku Corporation of Japan, sample testing conditions: Cu target, Kα ray (λ=0.1542nm), tube voltage 40kV, tube current 30mA, scanning rate 20° / min, range 3°~55°.
[0038] Product analysis: carried out on a Fuli GC9790 gas chromatograph, HP-PLOT / Q column, FID detector; dimethyl ether (DME) conversion rate and methyl acetate (MA) selectivity data were uniformly calculated by the area normalization method.
[0039] In the examples of this application, the conversion rate and selectivity are calculated as follows:
[0040] In the examples and comparative examples, the conversion of dimethyl ether (DME) and the selectivity of methyl acetate (MA) are calculated based on the carbon molar number of dimethyl ether:
[0041] Dimethyl ether conversion rate = [(molar number of dimethyl ether carbon in the feed gas) - (molar number of dimethyl ether carbon in the product)] ÷ (molar number of dimethyl ether carbon in the feed gas) × (100%);
[0042] Methyl acetate selectivity = (2 / 3) × (the number of moles of carbon of methyl acetate in the product) ÷ [(the number of moles of carbon of dimethyl ether in the feed gas) - (the number of moles of carbon of dimethyl ether in the product)] × (100%).
[0043] Example 1
[0044] H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300°C in a N2 atmosphere for 1 h, 2-methylimidazole in the activator was heated at 200°C, saturated vapor was introduced into the reactor with N2, adsorbed at 300°C for 2 h, and then switched to N2 purge for 2 h to obtain H-MOR molecular sieve modified with 2-methylimidazole.
[0045] Example 2
[0046] H-MOR was tableted, crushed and sieved, 2g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300°C in a N2 atmosphere for 1h, 2-methylimidazole in the activator was heated at 200°C, saturated vapor was introduced into the reactor with N2, adsorbed at 350°C for 2h, and then switched to N2 purge for 2h to obtain 2-methylimidazole-modified H-MOR molecular sieve.
[0047] Example 3
[0048] H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300°C in a N2 atmosphere for 1 h, 4-methylimidazole in the activator was heated at 200°C, saturated vapor was introduced into the reactor with N2, adsorbed at 300°C for 2 h, and then switched to N2 purge for 2 h to obtain H-MOR molecular sieve modified with 4-methylimidazole.
[0049] Example 4
[0050] H-MOR was tableted, crushed and sieved, 2g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300℃ for 1h in N2 atmosphere, 4-methylimidazole in the activator was heated at 200℃, saturated vapor was introduced into the reactor with N2, adsorbed at 350℃ for 2h, and then switched to N2 purge for 2h to obtain H-MOR molecular sieve modified with 4-methylimidazole.
[0051] Example 5
[0052] H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300°C in a N2 atmosphere for 1 h, 1,2-methylimidazole in the activator was heated at 200°C, saturated vapor was introduced into the reactor with N2, adsorbed at 300°C for 2 h, and then switched to N2 purge for 2 h to obtain H-MOR molecular sieve modified with 1,2-methylimidazole.
[0053] Example 6
[0054] H-MOR was tableted, crushed and sieved, 2g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300℃ for 1h in N2 atmosphere, 1,2-methylimidazole in the activator was heated at 200℃, saturated vapor was introduced into the reactor with N2, adsorbed at 350℃ for 2h, and then switched to N2 purge for 2h to obtain H-MOR molecular sieve modified with 1,2-methylimidazole.
[0055] Example 7
[0056] H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300°C in a N2 atmosphere for 1 h, 2,4-methylimidazole in the activator was heated at 200°C, saturated vapor was introduced into the reactor with N2, adsorbed at 300°C for 2 h, and then switched to N2 purge for 2 h to obtain H-MOR molecular sieve modified with 2,4-methylimidazole.
[0057] Example 8
[0058] H-MOR was tableted, crushed and sieved, 2g of 20-40 mesh catalyst was weighed and placed in a reactor, dried at 300℃ for 1h in N2 atmosphere, 2,4-methylimidazole in the activator was heated at 200℃, saturated vapor was introduced into the reactor with N2, adsorbed at 350℃ for 2h, and then switched to N2 purge for 2h to obtain H-MOR molecular sieve modified with 2,4-methylimidazole.
[0059] Comparative Example 1
[0060] The H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and placed in a reactor, and dried at 300° C. in a N 2 atmosphere for 1 h to obtain an unmodified H-MOR molecular sieve.
[0061] Comparative Example 2
[0062] The H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and exchanged with 1-methylimidazole hydrochloride (aqueous solution of 1-methylimidazole hydrochloride, concentration of 1.0 mol / L, amount of 20 ml), treated at 80°C for 4 h, filtered, washed, dried, placed in a reactor, and dried at 300°C in a N2 atmosphere for 1 h to obtain the H-MOR molecular sieve modified with 1-methylimidazole hydrochloride.
[0063] Comparative Example 3
[0064] The H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and exchanged with 1,3-dimethylimidazole chloride (aqueous solution of 1,3-dimethylimidazole chloride, concentration was 1.0 mol / L, amount was 20 ml), treated at 80°C for 4 h, filtered and washed, dried, placed in a reactor, and dried at 300°C in N2 atmosphere for 1 h to obtain H-MOR molecular sieve modified with 1,3-dimethylimidazole chloride.
[0065] Comparative Example 4
[0066] The H-MOR was tableted, crushed and sieved, 2 g of 20-40 mesh catalyst was weighed and exchanged with 1-butyl-3-methylimidazolium chloride (aqueous solution of 1-butyl-3-methylimidazolium chloride, concentration 1.0 mol / L, amount 20 ml), treated at 80°C for 4 h, filtered, washed, dried, placed in a reactor, and dried at 300°C in a N2 atmosphere for 1 h to obtain the H-MOR molecular sieve modified with 1-butyl-3-methylimidazolium chloride.
[0067] Comparative Example 5
[0068] The operation is the same as that of Example 1, except that 2-methylimidazole is replaced by 2-methylpyridine to obtain H-MOR molecular sieve modified with 2-methylpyridine.
[0069] Relative crystallinity analysis of modified H-MOR molecular sieve:
[0070] XRD analysis was performed on the modified H-MOR molecular sieves of Examples 1, 2, 5, 7 and Comparative Examples 2, 3, 4 to obtain relative crystallinity data, which reflects the crystal structure of the modified molecular sieve and affects the catalytic performance of the molecular sieve. The test data are shown in Table 1.
[0071] Table 1
[0072] Example / Comparative Example Modification of H-MOR molecular sieve Relative crystallinity (%) Example 1 2-Methylimidazole modified 100 Example 2 2-Methylimidazole modified 98 Example 5 1,2-Methylimidazole modified 99 Example 7 2,4-Methylimidazole modified 102 Comparative Example 2 1-Methylimidazole hydrochloride modification 80 Comparative Example 3 1,3-Dimethylimidazolium chloride modification 85 Comparative Example 4 1-Butyl-3-methylimidazolium chloride modified 83
[0073] It can be seen from Table 1 that the relative crystallinity of the modified H-MOR molecular sieves of Examples 1, 2, 5, and 7 remains unchanged, that is, the modification by saturated vapor of imidazole organic matter will not affect the crystallinity of the molecular sieve; the relative crystallinity of the modified H-MOR molecular sieves of Comparative Examples 2, 3, and 4 is slightly above 80%, that is, after modification by imidazole salt solution, because it is carried out in liquid, the crystallinity of the molecular sieve is significantly reduced, and its catalytic performance is also significantly reduced.
[0074] Evaluation of carbonylation of dimethyl ether to produce methyl acetate:
[0075] The H-MOR molecular sieve obtained in the above examples and comparative examples was used as a catalyst. The activity evaluation was carried out at a temperature of 225°C and a pressure of 2.0 MPa. The feed volume ratio DME:N2:CO was 1:13:7, and the volume space velocity was 1800 h -1 The operation was continued, and the reaction results were detected after 30 hours and 500 hours of operation, as shown in Table 2.
[0076] Table 2
[0077]
[0078] Note: MA selectivity is greater than 99%.
[0079] As shown in Table 2, for the catalysts modified by saturated steam of imidazole organic matter in Examples 1-8, after running for 500 hours, the DME conversion rate did not decrease significantly, and was always maintained at more than 77%. For the unmodified comparative example 1, after running for 500 hours, the DME conversion rate dropped to 20%; for the comparative examples 2-4 modified by imidazole salt solution, the best performing comparative example 3 also dropped to 58%, and comparative examples 2 and 4 dropped to 2% and 8% respectively. It can be seen that the imidazole salt solution modification, because it is carried out in liquid, not only affects the crystallinity of the catalyst, but also has a poor modification effect; for the comparative example 5 modified by 2-methylpyridine, although it is also modified by saturated steam, due to the difference in the modified substances, after running for 500 hours, the DME conversion rate dropped to 45%.
[0080] In summary, compared with the existing modification methods, the hydrogen-type mordenite obtained by the modification method of the present application has higher stability and exhibits better catalytic activity and stability in the reaction of carbonylation of dimethyl ether to prepare methyl acetate.
[0081] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for modifying a dimethyl ether carbonylation catalyst, characterized in that: The modification method comprises the following steps: The H-MOR molecular sieve is placed in a reactor, and saturated vapor containing imidazole organic matter is introduced until adsorption is saturated to obtain a modified H-MOR molecular sieve; The imidazole organic compound is selected from at least one of 2-methylimidazole, 4-methylimidazole, 1,2-methylimidazole, 2,4-methylimidazole, 2-ethylimidazole, 4-ethylimidazole, 1,2-ethylimidazole and 2,4-ethylimidazole.
2. The modification method according to claim 1, characterized in that: Place the H-MOR molecular sieve in a reactor, heat to 200-400°C, introduce gas, treat for 1-5 hours, and then introduce saturated steam containing imidazole organic matter; The gas is selected from at least one of He, N2, argon and air.
3. The modification method according to claim 1, characterized in that: The introduction of saturated steam containing imidazole organic matter comprises: The solid of the imidazole organic compound is heated and liquefied, and then the saturated vapor of the imidazole organic compound is introduced through the gas; The gas is selected from at least one of He, N2, argon and air.
4. The modification method according to claim 3, characterized in that: The heating temperature is 200-400°C.
5. The modification method according to claim 1, characterized in that: The adsorption temperature is 300-450°C; The adsorption time is 1-24 hours.
6. The modification method according to claim 1, characterized in that: After adsorption saturation, gas is introduced for purging for 1-5 hours to obtain the modified H-MOR molecular sieve; The gas is selected from at least one of He, N2, argon and air.
7. The modification method according to claim 1, characterized in that: The silicon-aluminum ratio of the H-MOR molecular sieve is 5-50.
8. A method for preparing methyl acetate by carbonylation of dimethyl ether, characterized in that: The raw gas containing dimethyl ether and carbon monoxide is introduced into the reactor, contacted with the catalyst, and reacted to obtain methyl acetate; The catalyst is selected from the H-MOR molecular sieve obtained by the modification method according to any one of claims 1 to 7.
9. The method according to claim 8, characterized in that The reaction conditions are: the molar ratio of dimethyl ether to carbon monoxide is 1:1-50, and the total reaction space velocity is 1000-2000h -1 , temperature is 200~280℃, pressure is 2~8MPa.
10. The method according to claim 8, characterized in that The reaction conditions are: the molar ratio of dimethyl ether to carbon monoxide is 1:1-10, and the total reaction space velocity is 1500-2000h -1 , temperature is 210~250℃, and pressure is 2~5MPa.