Method for preparing isobutyric acid through propylene carbonylation
By using an acidic molecular sieve catalyst in a fixed-bed reactor to carry out the carbonylation reaction of propylene, the problems of high raw material price and environmental protection in the preparation of isobutyric acid have been solved, and the preparation of isobutyric acid that is easy to separate and can be produced on a large scale has been realized.
Patent Information
- Application Number
- CN202411615300.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2026-05-15
AI Technical Summary
Existing isobutyric acid preparation processes suffer from problems such as high raw material prices, harsh reaction conditions, difficulty in product separation, high difficulty in industrialization, and environmental unfriendliness.
An acidic molecular sieve catalyst was used to carry out the carbonylation reaction of propylene in a fixed-bed reactor with propylene, carbon monoxide and water to produce isobutyric acid. The acidic molecular sieves used included hydrogen form ZSM-35, ZSM-11 and ZSM-5. The reaction conditions were optimized to 180-320℃ and 2-10MPa. The isobutyric acid was easy to separate after it was generated.
It achieves the advantages of cheap and readily available raw materials, low corrosivity, easy product separation, and easy industrialization of fixed-bed technology, making it suitable for large-scale production and reducing the discharge of waste gas, wastewater, and solid waste.
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Abstract
Description
Technical Field
[0001] This application relates to a method for producing isobutyric acid by carbonylation of propylene, which belongs to the field of catalytic chemistry. Background Technology
[0002] Isobutyric acid (CH3CH(CH3)COOH) is an important chemical product widely used in the manufacture of coatings, plasticizers, photoinitiators, fragrances, food preservatives, pesticides, and disinfectants. It is expensive and in high demand. Isobutyric acid is also recognized as a safe chemical by the Food Flavor Manufacturers Association. Industrially, isobutyric acid can be synthesized from isobutanol by oxidation with potassium permanganate in an alkaline medium followed by distillation. This process generates a large amount of waste residue and does not meet green environmental protection requirements. Alternatively, isobutyric acid can be synthesized from propylene, carbon monoxide, and water under homogeneous reaction conditions of high temperature, high pressure, and strong acids (such as concentrated sulfuric acid and hydrofluoric acid) based on the Koch carbonylation mechanism. Although the raw materials for the homogeneous Koch carbonylation method are inexpensive and readily available, the reaction conditions are harsh, the reactor materials are extremely demanding, product separation is difficult, and industrialization is challenging. Summary of the Invention
[0003] Currently, the process of oxidizing isobutanol to produce isobutyric acid not only involves high raw material costs but also generates a large amount of solid waste, failing to meet the requirements of green environmental protection. Therefore, this application provides a method for producing isobutyric acid by catalytic carbonylation of propylene using acidic molecular sieves. This method uses inexpensive and readily available raw materials, has low system corrosivity, facilitates product separation, and minimizes the discharge of waste gas, wastewater, and solid waste.
[0004] Based on this, this application provides a method for producing isobutyric acid by carbonylation of propylene, comprising passing a raw material containing propylene, carbon monoxide and water through a reactor supported on an acidic molecular sieve catalyst and reacting it under predetermined reaction conditions to obtain a product containing isobutyric acid.
[0005] A method for producing isobutyric acid by propylene carbonylation, the method comprising:
[0006] Raw materials containing propylene, carbon monoxide, and water are passed through a reactor loaded with an acidic molecular sieve catalyst to produce a product containing isobutyric acid.
[0007] 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.
[0008] The acidic molecular sieve catalyst is an acidic molecular sieve catalyst with a 10-membered ring channel structure.
[0009] 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.
[0010] Optionally, the silicon-to-aluminum ratio (SiO2 / Al2O3) of the acidic molecular sieve catalyst is 10–200.
[0011] Preferably, the silicon-to-aluminum ratio (SiO2 / Al2O3) of the acidic molecular sieve catalyst is 20–80.
[0012] 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.
[0013] Optionally, the molar ratio of carbon monoxide to propylene is 5:1 to 200:1.
[0014] Preferably, the molar ratio of carbon monoxide to propylene is 30:1 to 100:1.
[0015] Optionally, the molar ratio of carbon monoxide to propylene 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.
[0016] Optionally, the molar ratio of water to propylene is 0.5:1 to 20:1.
[0017] Preferably, the molar ratio of water to propylene is 2:1 to 5:1.
[0018] Optionally, the molar ratio of water to propylene 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.
[0019] Optionally, the reaction temperature is 180–320°C.
[0020] Preferably, the reaction temperature is 230–280°C.
[0021] 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.
[0022] Optionally, the reaction pressure is 2 to 10 MPa.
[0023] Preferably, the reaction pressure is 4–6 MPa.
[0024] 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.
[0025] Optionally, the mass hourly space velocity (MHV) of propylene is 0.05–1.0 h⁻¹. -1 .
[0026] Preferably, the mass hourly space velocity (MSV) of propylene is 0.1–0.3 h⁻¹. -1 .
[0027] Optionally, the space velocity of propylene 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.
[0028] Optionally, the reactor is a fixed-bed reactor.
[0029] The beneficial effects that this application can produce include:
[0030] 1) This application proposes a novel method for the carbonylation of propylene to produce isobutyric acid using acidic molecular sieve catalysis.
[0031] 2) The isobutyric acid preparation method in this application uses inexpensive and readily available raw materials, has low corrosivity, is easy to separate products, produces less waste, is easy to engineer as a fixed-bed process, and is suitable for large-scale single-unit production. Detailed Implementation
[0032] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0033] 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.
[0034] This application provides a method for producing isobutyric acid by carbonylation of propylene, comprising passing a raw material containing propylene, carbon monoxide and water through a reactor supported on an acidic molecular sieve catalyst and reacting it under predetermined reaction conditions to obtain a product containing isobutyric acid.
[0035] The reaction equation for the carbonylation of propylene to isobutyric acid catalyzed by acidic molecular sieves is as follows:
[0036] CH3-CH=CH2+CO+H2O=(CH3)2CHCOOH
[0037] It will also be accompanied by side reactions such as propylene hydration to form isopropanol and propylene hydrogen transfer to form other hydrocarbons.
[0038] The above-mentioned mechanism of propylene carbonylation to isobutyric acid is as follows: propylene reacts with Brønsted acid (ZEO-H) on acidic molecular sieves to generate surface isopropoxy group (ZEO-CH(CH3)2) species; carbon monoxide inserts into the surface isopropoxy group to form surface isobutyryl group (ZEO-CO CH(CH3)2) species; isobutyryl group reacts with water to generate isobutyric acid ((CH3)2CHCOOH), which is desorbed while Brønsted acid (ZEO-H) is reduced.
[0039] Surface isopropoxy species can also react directly with water to generate isopropanol, which desorbs and reduces Brønsted acid.
[0040] In some embodiments, the acidic molecular sieve catalyst is an acidic molecular sieve catalyst having a 10-membered ring channel structure.
[0041] In some embodiments, the acidic molecular sieve catalyst is selected from at least one of acidic molecular sieves having a FER structure, an acidic molecular sieve having a MEL structure, an acidic molecular sieve having an MFI structure, an acidic molecular sieve having an MFS structure, an acidic molecular sieve having an MTT structure, an acidic molecular sieve having a TON structure, and an acidic molecular sieve having a MWW structure.
[0042] In some embodiments, the acidic molecular sieve catalyst is selected from at least one of hydrogen-form ZSM-35 molecular sieve, hydrogen-form ZSM-11 molecular sieve, hydrogen-form ZSM-5 molecular sieve, hydrogen-form ZSM-57 molecular sieve, hydrogen-form ZSM-23 molecular sieve, hydrogen-form ZSM-22 acidic molecular sieve, and hydrogen-form MCM-22 molecular sieve.
[0043] In some embodiments, the acidic molecular sieve catalyst comprises a shaped acidic molecular sieve catalyst.
[0044] In some embodiments, the shaped acidic molecular sieve catalyst contains binders such as alumina and silicon dioxide.
[0045] In some embodiments, the raw material contains components such as nitrogen, argon, helium, and hydrogen.
[0046] In some embodiments, the reactor is a fixed-bed reactor.
[0047] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially.
[0048] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.
[0049] The analysis method in the embodiments of this application is as follows:
[0050] 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.
[0051] In the embodiments of this application, the conversion rate and selectivity are calculated as follows:
[0052] Both propylene conversion and isobutyric acid selectivity are calculated based on the number of carbon moles:
[0053] Propylene conversion rate = [(molar carbon content of propylene in feed) - (molar carbon content of propylene in discharge)] ÷ (molar carbon content of propylene in feed) × 100%
[0054] Isobutyric acid selectivity = (number of carbon moles of isobutyric acid in the discharge) ÷ (number of carbon moles of all products) × 100%
[0055] Example 1
[0056] 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. Propylene 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 propylene (CO:C3H6), molar ratio of water to propylene (H2O:C3H6), propylene mass hourly space velocity (WHSV), and reaction results after one day (24h) of operation are shown in Table 1.
[0057] Examples 2-10
[0058] 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.
[0059] Comparative Example 1
[0060] 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.
[0061] Comparative Example 2
[0062] 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.
[0063] Table 1. Reaction conditions and results of Examples 1-10 and Comparative Examples 1-2
[0064]
[0065] Note: Product selectivity <0.1% means that the product is hardly generated.
[0066] 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 producing isobutyric acid by propylene carbonylation, characterized in that, The method includes: Raw materials containing propylene, carbon monoxide, and water are passed through a reactor loaded with an acidic molecular sieve catalyst to produce a product containing isobutyric 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 propylene is 5:1 to 200:1; Preferably, the molar ratio of carbon monoxide to propylene is 30:1 to 100:
1.
4. The method according to claim 1, characterized in that, The molar ratio of water to propylene is 0.5:1 to 20:1; Preferably, the molar ratio of water to propylene 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 propylene is 0.05–1.0 h⁻¹. -1 ; Preferably, the mass hourly space velocity (MSV) of propylene is 0.1–0.3 h⁻¹. -1 .
8. The method according to claim 1, characterized in that, The reactor is a fixed-bed reactor.