Method for preparing propionic acid through ethylene carbonylation
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-11-13
- Publication Date
- 2026-05-15
AI Technical Summary
Existing methods for producing propionic acid by ethylene carbonylation require high temperature and pressure, resulting in highly corrosive equipment, difficult product separation, low catalyst stability, high cost of precious metal catalysts, and problems with iodide auxiliaries.
Acidic molecular sieve catalysts, such as ZSM-35, ZSM-11, and ZSM-5, are used to carry out the ethylene carbonylation reaction at a lower pressure in a fixed-bed reactor, avoiding the use of precious metals and iodide auxiliaries and simplifying product separation.
This technology enables the preparation of propionic acid under lower pressure, reduces equipment corrosion, simplifies product separation, is suitable for large-scale production, improves catalyst stability, and reduces costs.
Smart Images
Figure BDA0005132070440000051 
Figure BDA0005132070440000061
Abstract
Description
Technical Field
[0001] This application relates to a method for producing propionic acid by carbonylation of ethylene, which belongs to the field of catalytic chemistry. Background Technology
[0002] Propionic acid (CH3CH2COOH) is an important chemical product and organic intermediate, widely used in synthetic plastics, pharmaceuticals, pesticides, feed, and fragrances. Due to its biocompatibility, propionic acid and its propionate salts are also commonly used as food preservatives. Currently, the main industrial production method for propionic acid is the Reppe process from BASF in Germany. This process uses nickel carbonyl as a catalyst, and ethylene, carbon monoxide, and water undergo a carbonyl synthesis reaction at a reaction temperature of 250–320℃ and a reaction pressure of 10–30 MPa to produce propionic acid in one step. The Reppe method involves high reaction pressure, and propionic acid is highly corrosive under the reaction conditions, requiring extremely sophisticated equipment. Ethanol carbonylation is another method for preparing propionic acid. The homogeneous carbonylation of ethanol is similar to the mature methanol carbonylation method, mainly using noble metal complex catalysts such as Rh and Ir, and also requiring the addition of iodide auxiliaries. In the homogeneous carbonylation of ethanol, not only are the noble metal catalysts expensive, but the reaction also produces severely corrosive iodide substances, and the reaction pressure is also high, requiring sophisticated equipment and making product separation difficult. The heterogeneous carbonylation of ethanol generally employs supported metal catalysts. The active component can be either noble metals or non-noble metals such as Zn, Pb, Sn, Cu, and Ni. While the heterogeneous carbonylation of ethanol can improve some of the problems of the homogeneous method, it still suffers from issues such as low catalyst stability, severe carbon deposition, and metal loss. Furthermore, it is difficult to avoid the addition of iodide promoters. Summary of the Invention
[0003] Currently, the Reppe process for the carbonylation of ethylene to produce propionic acid requires high temperature, high pressure, and strong corrosion, resulting in harsh reaction conditions, demanding equipment, and difficult product separation. Therefore, this application provides a method for the carbonylation of ethylene to produce propionic acid using acidic molecular sieves. This method does not require the use of metal or iodide auxiliaries, has low system corrosivity, and facilitates product separation.
[0004] A method for producing propionic acid by carbonylation of ethylene, the method comprising:
[0005] Raw materials containing ethylene, carbon monoxide, and water are passed through a reactor loaded with an acidic molecular sieve catalyst to produce a product containing propionic acid.
[0006] The acidic molecular sieve catalyst is selected from at least one of the following: hydrogen-type ZSM-35 molecular sieve, hydrogen-type ZSM-11 molecular sieve, hydrogen-type ZSM-5 molecular sieve, hydrogen-type ZSM-57 molecular sieve, hydrogen-type ZSM-23 molecular sieve, hydrogen-type ZSM-22 acidic molecular sieve, and hydrogen-type MCM-22 molecular sieve.
[0007] The acidic molecular sieve catalyst is an acidic molecular sieve catalyst with a 10-membered ring channel structure.
[0008] The acidic molecular sieve catalyst is selected from at least one of the following: acidic molecular sieves with FER structure, acidic molecular sieves with MEL structure, acidic molecular sieves with MFI structure, acidic molecular sieves with MFS structure, acidic molecular sieves with MTT structure, acidic molecular sieves with TON structure, and acidic molecular sieves with MWW structure.
[0009] Optionally, the silicon-to-aluminum ratio (SiO2 / Al2O3) of the acidic molecular sieve catalyst is 10–200.
[0010] Preferably, the silicon-to-aluminum ratio (SiO2 / Al2O3) of the acidic molecular sieve catalyst is 20–80.
[0011] Optionally, the silicon-aluminum ratio (SiO2 / Al2O3) of the acidic molecular sieve catalyst is selected from any value or a range between 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, and 200.
[0012] Optionally, the molar ratio of carbon monoxide to ethylene is 5:1 to 200:1.
[0013] Preferably, the molar ratio of carbon monoxide to ethylene is 30:1 to 100:1.
[0014] Optionally, the molar ratio of carbon monoxide to ethylene is selected from any value or a range between 5:1, 10:1, 20:1, 50:1, 75:1, 100:1, 125:1, 150:1, 175:1, and 200:1.
[0015] Optionally, the molar ratio of water to ethylene is 0.5:1 to 20:1.
[0016] Preferably, the molar ratio of water to ethylene is 2:1 to 5:1.
[0017] Optionally, the molar ratio of water to ethylene is selected from any value or a range between 0.5:1, 1.0:1, 2.0:1, 3.0:1, 4.0:1, 5.0:1, 6.0:1, 7.0:1, 8.0:1, 9.0:1, 10.0:1, 12.0:1, 15.0:1, 17.5:1, and 20:1.
[0018] Optionally, the reaction temperature is 180–320°C.
[0019] Preferably, the reaction temperature is 230–280°C.
[0020] Optionally, the reaction temperature is selected from any value or a range between 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, and 320°C.
[0021] Optionally, the reaction pressure is 2 to 10 MPa.
[0022] Preferably, the reaction pressure is 4–6 MPa.
[0023] Optionally, the pressure of the reaction is selected from any value of 2MPa, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa, 10MPa or a range between any two.
[0024] Optionally, the mass hourly space velocity (MSV) of ethylene is 0.05–1.0 h⁻¹. -1 .
[0025] Preferably, the mass hourly space velocity (MSV) of ethylene is 0.1–0.3 h⁻¹. -1 .
[0026] Optionally, the space velocity of ethylene is selected from 0.05 h⁻¹. -1 0.1h -1 0.15h -1 0.2h -1 0.25h -1 0.3h -1 0.35h -1 0.4h -1 0.45h -1 0.5h -1 0.55h -1 0.6h -1 0.65h -1 0.7h -1 0.75h -1 0.8h -1 0.85h -1 0.9h -1 0.95h -1 1.0h -1 Any value in the range or any value between the two.
[0027] Optionally, the reactor is a fixed-bed reactor.
[0028] The beneficial effects that this application can produce include:
[0029] 1) This application proposes a new method for the carbonylation of ethylene to produce propionic acid using acidic molecular sieve catalysis.
[0030] 2) The propionic acid preparation method in this application has a catalyst system that does not contain metal and iodide additives, the reaction products are easy to separate from the catalyst, the gas phase reaction system has low corrosivity, the fixed bed process is easy to engineer, and it is suitable for large-scale single-unit production. Detailed Implementation
[0031] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0032] The endpoints and any values of the ranges disclosed in this application are not limited to the precise ranges or values, but should be understood to include those approximations of such ranges or values. For numerical ranges, the endpoint values of the various ranges and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0033] This application provides a method for producing propionic acid by carbonylation of ethylene, comprising passing a raw material containing ethylene, carbon monoxide and water through a reactor supported on an acidic molecular sieve catalyst and carrying out a hydrolysis reaction under predetermined reaction conditions to obtain a product containing propionic acid.
[0034] The reaction equation for the carbonylation of ethylene to propionic acid catalyzed by acidic molecular sieves is as follows:
[0035] CH2=CH2+CO+H2O=CH3CH2COOH
[0036] It will also be accompanied by side reactions such as ethylene hydration to produce ethanol and ethylene hydrogen transfer to produce other hydrocarbons.
[0037] The above-mentioned mechanism of ethylene carbonylation to propionic acid is as follows: ethylene reacts with Brønsted acid (ZEO-H) on acidic molecular sieves to generate surface ethoxylate (ZEO-CH2CH3) species; carbon monoxide inserts into the surface ethoxylate to form surface propionyl (ZEO-COCH2CH3) species; propionyl reacts with water to generate propionic acid (CH3CH2COOH), which is desorbed while Brønsted acid (ZEO-H) is reduced.
[0038] Surface ethoxy species can also react directly with water to generate ethanol, which then desorbs and reduces Brønsted acid.
[0039] In some embodiments, the acidic molecular sieve catalyst comprises a shaped acidic molecular sieve catalyst.
[0040] In some embodiments, the shaped acidic molecular sieve catalyst contains binders such as alumina and silicon dioxide.
[0041] In some embodiments, the raw material contains components such as nitrogen, argon, helium, and hydrogen.
[0042] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially.
[0043] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.
[0044] The analysis method in the embodiments of this application is as follows:
[0045] The products and unreacted raw materials were analyzed online using an Agilent 7890B gas chromatograph, with its FID detector connected to a PLOT-Q capillary column and its TCD detector connected to a Porapak Q packed column.
[0046] In the embodiments of this application, the conversion rate and selectivity are calculated as follows:
[0047] Both ethylene conversion and propionic acid selectivity are calculated based on the number of carbon moles:
[0048] Ethylene conversion rate = [(molar carbon content of ethylene in feed) - (molar carbon content of ethylene in discharge)] ÷ (molar carbon content of ethylene in feed) × 100%
[0049] Propionic acid selectivity = (number of carbon moles of propionic acid in the discharge) ÷ (number of carbon moles of all products) × 100%
[0050] Example 1
[0051] 2g of acidic H-ZSM-35 molecular sieve catalyst (SiO2 / Al2O3 = 40, 20-40 mesh particles) was loaded into a container with an inner diameter of [missing information]. In a fixed-bed reactor, the reactor interior contains Thermocouple sheaths were used. Ethylene and carbon monoxide were fed via mass flow meters, while water was fed via a horizontal flow pump. The raw materials were mixed and preheated before entering the catalyst bed for reaction. The products were heated and analyzed online using gas chromatography. Reaction conditions, including reaction temperature (T), reaction pressure (P), molar ratio of carbon monoxide to ethylene (CO:C2H4), molar ratio of water to ethylene (H2O:C2H4), ethylene mass hourly space velocity (WHSV), and reaction results after one day (24h) of operation are shown in Table 1.
[0052] Examples 2-10
[0053] Except for the changes in catalyst and reaction conditions, the experimental steps and apparatus of Examples 2 to 10 are the same as those of Example 1. The reaction conditions and reaction results after running for one day (24 hours) are shown in Table 1.
[0054] Comparative Example 1
[0055] The catalyst in Example 1 was replaced with H-MOR silica molecular sieve (SiO2 / Al2O3 = 15), and the experimental steps and apparatus were the same as in Example 1. The reaction conditions and reaction results after one day (24h) are shown in Table 1.
[0056] Comparative Example 2
[0057] The catalyst in Example 1 was replaced with a Py / H-MOR pyridine adsorption silicate molecular sieve (SiO2 / Al2O3 = 15). Py / H-MOR was prepared by treating H-MOR at 280°C and atmospheric pressure with a mixture of pyridine and nitrogen at a flow rate of 500 ml / min for 6 hours until adsorption saturation. Other experimental procedures and apparatus were consistent with Example 1. The reaction conditions and results after one day (24 h) of operation are shown in Table 1.
[0058] Table 1. Ethylene carbonylation reaction conditions and results of Examples 1-10 and Comparative Examples 1-2
[0059]
[0060]
[0061] Note: Product selectivity <0.1% means that the product is hardly generated.
[0062] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing propionic acid by carbonylation of ethylene, characterized in that, The method includes: Raw materials containing ethylene, carbon monoxide, and water are passed through a reactor loaded with an acidic molecular sieve catalyst to produce a product containing propionic acid. The acidic molecular sieve catalyst is selected from at least one of the following: hydrogen-type ZSM-35 molecular sieve, hydrogen-type ZSM-11 molecular sieve, hydrogen-type ZSM-5 molecular sieve, hydrogen-type ZSM-57 molecular sieve, hydrogen-type ZSM-23 molecular sieve, hydrogen-type ZSM-22 acidic molecular sieve, and hydrogen-type MCM-22 molecular sieve.
2. The method according to claim 1, characterized in that, The silicon-aluminum molecular ratio (SiO2 / Al2O3) of the acidic molecular sieve catalyst is 10–200. Preferably, the silicon-to-aluminum ratio (SiO2 / Al2O3) of the acidic molecular sieve catalyst is 20–80.
3. The method according to claim 1, characterized in that, The molar ratio of carbon monoxide to ethylene is 5:1 to 200:1; Preferably, the molar ratio of carbon monoxide to ethylene is 30:1 to 100:
1.
4. The method according to claim 1, characterized in that, The molar ratio of water to ethylene is 0.5:1 to 20:1; Preferably, the molar ratio of water to ethylene is 2:1 to 5:
1.
5. The method according to claim 1, characterized in that, The reaction temperature is 180–320°C; Preferably, the reaction temperature is 230–280°C.
6. The method according to claim 1, characterized in that, The reaction pressure is 2–10 MPa; Preferably, the reaction pressure is 4–6 MPa.
7. The method according to claim 1, characterized in that, The mass hourly space velocity (MSV) of ethylene is 0.05–1.0 h⁻¹. -1 ; Preferably, the mass hourly space velocity (MSV) of ethylene is 0.1–0.3 h⁻¹. -1 .
8. The method according to claim 1, characterized in that, The reactor used for the reaction is a fixed-bed reactor.