Production method and production system of dimethyl adipate

Abstract

The invention relates to the field of preparation of dimethyl adipate, in particular to a production method and system of dimethyl adipate. The production method comprises the following steps: carrying out carbonyl esterification reaction on raw materials containing butadiene, CO and methanol in the presence of a carbonyl esterification catalyst, and carrying out low-pressure flash evaporation on the obtained reaction mixture to obtain a gas component and a liquid-phase reaction liquid; carrying out evaporation treatment on the liquid-phase reaction liquid, and sequentially carrying out primary condensation and secondary condensation on the obtained light component; carrying out methanol removal treatment on the primary condensate to obtain a light component and a crude dimethyl adipate product; and carrying out light component removal treatment and heavy component removal treatment on the crude dimethyl adipate product to obtain a dimethyl adipate product and heavy components. According to the method and the process system, unreacted raw materials are recycled, separation of the raw materials, products and by-products is achieved through overall planning, the process flow is simple, operation is convenient and easy, and industrial operation is easy to achieve.

Description

Technical Field

[0001] The invention relates to the field of dimethyl adipate preparation, and in particular to a production method and system for dimethyl adipate. Background Art

[0002] Dimethyl adipate is a very important chemical intermediate. Dimethyl adipate hydrolysis can prepare adipic acid, and its hydrogenation can prepare hexylene glycol, which has high application value. In the current industry, the conventional way is to prepare dimethyl adipate by adipic acid esterification method, such as patent document CN111320543A a method for producing dimethyl adipate by adipic acid, which adopts adipic acid as raw material, and then double esterification is carried out after pre-esterification to obtain dimethyl adipate. CN106242970A a kind of equipment and method for producing dimethyl adipate also adopts adipic acid to produce dimethyl adipate. For the above method, from the aspect of raw materials, adipic acid cost is high, and the esterification process is difficult, and the resin catalyst needs to be regularly replaced, resulting in the high cost of dimethyl adipate.

[0003] Although other raw materials are used in the prior art to prepare dimethyl adipate, they often face major difficulties in the subsequent processing technology, such as inconvenient operation and low atomic utilization. How to coordinate the separation of raw materials, products, and by-products, as well as the recycling of unreacted raw materials, and how to facilitate industrialization cannot be easily solved. This is a problem faced by the development of new industrial production methods.

[0004] Therefore, how to provide a new industrial preparation process of dimethyl adipate with low raw material cost, atom economy and easy industrial operation is a technical problem that needs to be solved at present. Summary of the invention

[0005] The present invention uses butadiene, CO and methanol to generate dimethyl adipate under the action of a carbonylation catalyst, which has low raw material cost, atom economy, green and pollution-free, and is very competitive. The process flow of the present invention is simple, convenient and easy to operate, and easy to realize industrial operation. The process flow of the present invention is simple to operate and easy to industrialize.

[0006] The first aspect of the present invention is to provide a method for producing dimethyl adipate, comprising the following steps:

[0007] (1) subjecting a raw material containing butadiene, CO and methanol to a carbonylation reaction in the presence of a carbonylation catalyst to obtain a reaction mixture containing dimethyl adipate;

[0008] (2) flashing the reaction mixture containing dimethyl adipate at low pressure to obtain a gas component containing butadiene and CO and a liquid reaction liquid, and returning the gas component containing butadiene and CO to step (1);

[0009] (3) subjecting the liquid reaction liquid to evaporation treatment, and subjecting the obtained light components to primary condensation and secondary condensation in sequence, to obtain a primary condensate containing dimethyl adipate and a secondary condensate containing methanol and butadiene, respectively, and the secondary condensate is returned to step (1);

[0010] (4) removing methanol from the primary condensate containing dimethyl adipate to obtain a light component containing methanol and a crude dimethyl adipate product, and the light component is returned to step (1);

[0011] (5) subjecting the crude dimethyl adipate product to light component removal treatment to remove light component by-products, and then subjecting the crude dimethyl adipate product after light component removal treatment to heavy component removal treatment to obtain a dimethyl adipate product and a heavy component.

[0012] The inventors of the present invention have found that the reaction in step (1) is difficult to complete. By setting steps (2), (3) and (4), the unreacted raw materials can be sent back to the reactor for further reaction to reduce the unit consumption of raw materials. At the same time, due to the high reaction pressure and the high solubility of butadiene, multi-step recovery can be used to recover the dissolved butadiene.

[0013] For example, a methanol removal tower is set up to return unreacted methanol and butadiene to the reactor for repeated use, thereby reducing the unit consumption of butadiene and methanol.

[0014] The preferred technical scheme of the present invention is as follows: methanol, butadiene and CO enter the reactor for carbonyl esterification reaction, and after dimethyl adipate is generated, the reaction liquid enters the low-pressure separation tank, and after the dissolved butadiene and CO are released, the reaction liquid is compressed to the reaction pressure by the tail gas compressor and then returned to the reactor. The gas phase comes out of the low-pressure separation tank, which can be directly compressed and returned to the reactor for application. The liquid phase reaction liquid of the low-pressure separation tank enters the evaporator, and the evaporator adopts vacuum distillation to flash the light component. A part of the light component (first condensed) enters the methanol recovery tower, and the other part of the light component (secondary condensation) is pressurized and returned to the reactor for recycling. The uncondensed light component is discharged from the system as a discharge gas. The operating pressure of the above part is negative pressure, which may contain oxygen, so the gas phase needs to be condensed as much as possible, and the liquid phase returns to the reactor. The gas phase may contain oxygen, so it is directly discharged. If oxygen returns to the system, it will cause ligand degradation.

[0015] Methanol is recovered at the top of the methanol recovery tower, mixed with the light components condensed twice from the evaporator and then pressurized and returned to the reactor. The bottom of the methanol recovery tower is sent to a light removal tower, which removes other isomers of dimethyl adipate generated by the reaction and discharges them as light components. The bottom of the light removal tower is sent to a heavy removal tower, and the dimethyl adipate product is obtained at the top of the heavy removal tower, and the bottom is discharged as a heavy component.

[0016] In a preferred embodiment of the present invention, the gas component containing butadiene and CO obtained in step (2) is compressed and returned to step (1); a tail gas compressor is provided to press unreacted CO, methanol and butadiene back into the reactor for repeated use, thereby reducing the unit consumption of CO, methanol and butadiene.

[0017] According to the present invention, in step (1):

[0018] In a preferred embodiment of the present invention, the carbonylation catalyst is an organic palladium, preferably at least one of palladium acetate and palladium acetylacetonate.

[0019] In a preferred embodiment of the present invention, the usage of the carbonyl esterification catalyst is 50-4000 ppm, preferably 300-1000 ppm.

[0020] In a preferred embodiment of the present invention, the feed molar ratio of methanol to butadiene is (1-10):1, preferably (1.05-1.2):1, and / or the feed molar ratio of CO to butadiene is (1-1.4):1, preferably (1.02-1.05):1.

[0021] According to the present invention, in step (1):

[0022] In a preferred embodiment of the present invention, the operating temperature of the carbonyl esterification reaction is 80-160°C, preferably 90-120°C, and / or the operating pressure is 1-10 MPaG, preferably 2-5 MPaG; and / or the residence time is 0.5-100h, preferably 2-12h.

[0023] According to the present invention, in step (2):

[0024] After the carbonyl esterification reaction of the present invention, it first enters a low-pressure flash tank. In a preferred embodiment of the present invention, the operating pressure of the low-pressure flash tank is 0.15-1 MPaG, preferably 0.15-0.5 MPaG.

[0025] In a preferred embodiment of the present invention, the low-pressure flash evaporation is carried out at the temperature of the reaction mixture containing dimethyl adipate. The low-pressure flash evaporation does not require heating, and only the butadiene and methanol dissolved in the reaction solution are flashed out.

[0026] Preferably, the discharged gas from the low-pressure flash tank of the present invention enters a tail gas compressor, and the tail gas compressor returns to the reactor.

[0027] According to the present invention, in step (3):

[0028] The liquid phase of the low-pressure flash tank of the present invention is an evaporation tank. In a preferred embodiment of the present invention, the evaporation treatment operating temperature does not exceed 160°C, preferably 80-160°C, and more preferably 100-120°C. The evaporation treatment operating temperature is not recommended to exceed 160 degrees. If it exceeds 160 degrees, the ligand is easily degraded and the catalyst is easily deactivated. The higher the temperature, the faster the ligand degrades. The laboratory is controlled at 120 degrees. The evaporation temperature determines the operating pressure of the evaporation tank.

[0029] The light component of the evaporator of the present invention is first subjected to secondary condensation, and the primary condensation is preferably cooled by circulating water, and the condensate enters the methanol removal tower, and the secondary condensation is preferably cooled by low-temperature water, and the condensed product is returned to the reactor for reuse. After the uncondensed gas phase enters the vacuum pump, the tail gas is discharged.

[0030] In a preferred embodiment of the present invention, the outlet temperature of the primary condensation is not higher than 80°C, preferably 40-80°C.

[0031] In a preferred embodiment of the present invention, the outlet temperature of the secondary condensation is (-15°C) to (10)°C.

[0032] The purpose of methanol removal is to remove the residual methanol and butadiene in the reaction product dimethyl adipate, and the operating pressure is 0.01-0.025 MPaA. The operating pressure determines the bottom temperature. According to the present invention, in step (4):

[0033] In a preferred embodiment of the present invention, the operating pressure of methanol removal is 0.01-0.025 MPaA, preferably 0.018-0.022 MPaA; and / or, the tower bottom operating temperature is 120-190° C., preferably 120-180° C. The optimal operating pressure is 0.02 MPaA, at which the tower bottom temperature is about 180 degrees. When the temperature is too high, dimethyl adipate will produce by-products.

[0034] In a preferred embodiment of the present invention, the temperature at the tower top outlet is 5-30°C, preferably 5-20°C.

[0035] The purpose of the lightness removal column is to remove by-products produced during the carbonylation reaction, such as dimethyl 2-methylglutarate, dimethyl 2-ethylsuccinate and dimethyl propylmalonate. According to the present invention, in step (5):

[0036] In a preferred embodiment of the present invention, the conditions for light removal treatment include: an operating pressure of 0.001-0.01 MPaA, preferably 0.0015-0.003 MPaA, and / or a tower top operating temperature of 45-160°C, preferably 45-118°C, and a tower bottom operating temperature of 145-210°C.

[0037] The purpose of the deweighting tower is to remove the heavy components produced during distillation and reaction. In a preferred embodiment of the present invention, the conditions for deweighting treatment include: an operating pressure of 0.001-0.01 MPaA, preferably 0.0015-0.003 MPaA, and / or a tower top operating temperature of 46-170°C, preferably 46-122°C, and a tower bottom operating temperature of 148-215°C.

[0038] In a preferred embodiment of the present invention, the uncondensed light components obtained after the secondary condensation in step (3) are discharged.

[0039] In a preferred embodiment of the present invention, the light component by-product obtained in step (4) is discharged.

[0040] In a preferred embodiment of the present invention, the heavy components obtained after the de-heavy treatment in step (5) are discharged.

[0041] The second aspect of the present invention is to provide a production system of dimethyl adipate, preferably used in the production method of dimethyl adipate described in the first aspect, such as Figure 1 As shown, the production system comprises:

[0042] Reactor 1, low-pressure separation tank 2, evaporation tank 3, primary condenser 8, secondary condenser 9, methanol recovery tower 4, light removal tower 5 and heavy removal tower 6;

[0043] The feed inlet of the reactor 1 is connected to a butadiene raw material source, a CO raw material source and a methanol raw material source respectively.

[0044] The discharge port of the reactor 1 is connected to the feed port of the low-pressure separation tank 2;

[0045] The top discharge port of the low-pressure separation tank 2 is connected to the feed port of the reactor 1;

[0046] The bottom discharge port of the low-pressure separation tank 2 is connected to the feed port of the evaporation tank 3, and the top discharge port of the evaporation tank 3 is connected to the feed port of the primary condenser 8 and the feed port of the secondary condenser 9 in sequence;

[0047] The liquid outlet of the primary condenser 8 is connected to the feed inlet of the methanol recovery tower 4, and the liquid outlet of the secondary condenser 9 is connected to the feed inlet of the reactor 1; the top discharge port of the methanol recovery tower 4 is connected to the feed inlet of the reactor 1, the bottom discharge port of the methanol recovery tower 4 is connected to the feed inlet of the light removal tower 5, and the bottom discharge port of the light removal tower 5 is connected to the feed inlet of the weight removal tower 6;

[0048] The tops of the light-removing tower 5 and the heavy-removing tower 6 are respectively provided with discharge ports, and the bottom of the heavy-removing tower 6 is provided with a discharge port.

[0049] In a preferred embodiment of the present invention, the production system further comprises a gas compressor 7, and the top discharge port of the low-pressure separation tank 2 is connected to the feed port of the reactor 1 through the gas compressor 7. A tail gas compressor is provided to press unreacted CO, methanol and butadiene back to the reactor 1 for reuse, thereby reducing the unit consumption of CO, methanol and butadiene.

[0050] In a preferred embodiment of the present invention, the top discharge port of the methanol recovery tower 4 and the liquid outlet of the secondary condenser 9 are connected to the feed port of the reactor 1 through part of the same pipeline.

[0051] In a preferred embodiment of the present invention, the secondary condenser 9 is provided with an air outlet.

[0052] The advantages of the present invention are:

[0053] The invention provides a novel industrial preparation process of dimethyl adipate which has low raw material cost, atom economy and is easy to realize industrial operation. The process adopts butadiene, methanol and CO to react in one step to generate dimethyl adipate. The raw material price is cheap, the process flow is simple, the equipment investment is small and the operation is simple.

[0054] The present invention reuses unreacted raw materials through the method and process system of the present invention, and realizes the separation of raw materials, products and by-products in an overall manner. The process flow of the present invention is simple, convenient and easy to operate, and easy to realize industrial operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is the process flow chart of dimethyl adipate production.

[0056] 1 reactor; 2 low-pressure separation tank; 3 evaporation tank; 4 methanol recovery tower; 5 light removal tower; 6 heavy removal tower; 7 gas compressor; 8 primary condenser, 9 secondary condenser. DETAILED DESCRIPTION

[0057] The present invention is described in detail below in conjunction with specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0058] In the following examples, the composition of the raw materials in the reactor was detected by chromatographic analysis.

[0059] The unit consumption of butadiene is calculated as follows: the amount of butadiene fed divided by the amount of product output.

[0060] The calculation method of CO consumption is: the amount of CO in the feed divided by the amount of product output.

[0061] Example 1

[0062] 6405kg / h of room temperature methanol, 5395kg / h of butadiene, 9.15kg of palladium acetate catalyst, and 636kg / h of compressed gas (92.2% carbon monoxide, 5.99% methanol, 1.8% butadiene) from the tail gas compressor are mixed into the carbonyl esterification reactor. The reaction operating pressure is 4.0MPaG, the operating temperature is 120℃, and the reactor is a stirrer with a volume of about 60m 3 , three-stage fully mixed kettle, room temperature, the flow rate of about 5575.5kg / h of carbon monoxide can maintain the pressure of the three reactors, the residence time is 4h; the composition in the reactor was detected to be 0.03% CO, 1.92% methanol, 85.6% dimethyl adipate, 9.04% other isomers of dimethyl adipate, and 0.14% butadiene.

[0063] The gas discharged from the top of the reactor at a rate of about 521 kg / h (98.4% CO and 1.11% methanol) enters the tail gas compressor after decompression, and the reaction liquid of the reactor enters the low-pressure flash tank at a rate of about 19880 kg / h. The operating pressure of the low-pressure flash tank is 0.15 MPaG. At this time, the reaction liquid becomes 118°C, and the gas phase dissolved in the reaction liquid flashes out a non-condensable gas of about 116 kg / h (64% CO, 27.9% methanol and 7.9% butadiene) after being cooled to 40°C, and enters the tail gas compressor. After being compressed by the tail gas compressor, it returns to the reactor;

[0064] About 19764 kg / h (1.48% methanol, 89.3% dimethyl adipate, 9.11% dimethyl adipate isomers) of the reaction liquid at the bottom of the flash tank enters the evaporator, the operating pressure of the evaporator is 2.6 kPaA, the operating temperature is 120 ° C, and 2100 kg / h (93.1% dimethyl adipate and 6.8% dimethyl adipate isomers) of the catalyst solution is obtained at the bottom and returned to the reactor. The top gas phase is cooled by a primary cooling cooler. The inlet temperature is 120 degrees, the outlet temperature is 40 degrees) and then 17558 kg / h of crude product (1.27% methanol, 89.2% dimethyl adipate and 9.4% dimethyl adipate isomers) is obtained, which enters the methanol recovery tower. The top gas phase is subjected to secondary condensation at -15°C to obtain 82 kg / h of crude methanol (78.3% methanol, 3.66% dimethyl adipate and 29.3% butadiene), which is then returned to the reactor for reuse after being pressurized by a pump.

[0065] Crude methanol tower, tower top operating temperature -20 ° C, tower top outlet gas phase temperature 17 ° C, tower bottom operating temperature 167 ° C, methanol removal operating pressure is 0.02MPaA, 210kg / h crude methanol (98.7% methanol, 1.22% butadiene) is obtained at the top of the tower and returned to the reactor after being pressurized by a pump;

[0066] The bottom of the tower obtains 17348 kg / h of crude dimethyl adipate, which enters the light-removing tower. The operating pressure of the light-removing tower is 2.1 kPaA, the operating temperature of the tower top is 107.5°C, the operating temperature of the tower bottom is 145°C, 1550 kg / h of light components are obtained at the top of the tower, and 15798 kg / h of bottom liquid is obtained in the bottom of the tower. The tower then enters the heavy-removing tower. The operating pressure of the heavy-removing tower is 2.0 kPaA, the operating temperature of the tower top is 109°C, the operating temperature of the tower bottom is 150°C, 15775 kg / h of dimethyl adipate product (with a purity greater than 99.7%) is obtained at the top of the tower, and 23 kg / h of heavy components are obtained in the bottom of the tower.

[0067] The unit consumption of butadiene is 0.341, and the unit consumption of CO is 0.353.

[0068] Example 2

[0069] 6405kg / h of room temperature methanol, 5395kg / h of butadiene, 11.8kg of palladium acetate catalyst, and 715kg / h of compressed gas (95.5% carbon monoxide, 3.23% methanol, 1.2% butadiene) from the tail gas compressor are mixed into the carbonyl esterification reactor. The reaction operating pressure is 2.0MPaG, the operating temperature is 160℃, and the reactor is a stirrer with a volume of about 90m 3 , three-stage fully mixed kettle, normal temperature, flow rate, about 5574kg / h of carbon monoxide is blown in to maintain the pressure of the three reactors, the residence time is 5h, and the composition in the reactor is detected to be 0.0069% CO, 7.87% methanol, 82.67% dimethyl adipate, 8.43% other isomers of dimethyl adipate, and 0.032% butadiene.

[0070] The gas discharged from the top of the reactor at a rate of about 641 kg / h (92.5% of CO and 6.29% of methanol) enters the tail gas compressor after decompression, and the reaction liquid of the reactor enters the low-pressure flash tank at a rate of about 19821 kg / h. The operating pressure of the low-pressure flash tank is 0.15 MPaG. At this time, the reaction liquid becomes 157°C, and the gas phase dissolved in the reaction liquid flashes out a non-condensable gas of about 41 kg / h (87.7% of CO, 29.2% of methanol and 13.4% of butadiene) after being cooled to 40°C, and enters the tail gas compressor. After being compressed by the tail gas compressor, it returns to the reactor;

[0071] About 19782 kg / h (1.48% methanol, 89.3% dimethyl adipate, 9.11% dimethyl adipate isomers) of the reaction liquid at the bottom of the flash tank enters the evaporator, the operating pressure of the evaporator is 14 kPaA, the operating temperature is 160 ° C, and 2106 kg / h (91.9% dimethyl adipate and 7.9% dimethyl adipate isomers) of the catalyst solution is obtained at the bottom and returned to the reactor. The top gas phase is cooled by a primary cooling. The inlet temperature of the reactor is 160 degrees, the outlet temperature is 80 degrees) and 17518 kg / h of crude product (6.1% methanol, 85% dimethyl adipate and 8.88% dimethyl adipate isomers) is obtained, which enters the methanol recovery tower. The top gas phase is condensed at -15°C for two stages to obtain 151 kg / h of crude methanol (94.3% methanol, 2.28% dimethyl adipate and 2.84% butadiene), which is returned to the reactor for reuse after being pressurized by a pump.

[0072] Crude methanol tower, the temperature of the gas phase at the top outlet is 24°C, the operating temperature at the bottom of the tower is 190°C, the operating pressure of methanol removal is 0.025MPaA, and 210kg / h crude methanol (99% methanol, 0.96% butadiene) is obtained at the top of the tower

[0073] After being pressurized by a pump, it returns to the reactor;

[0074] The bottom of the tower obtains 17308kg / h of crude dimethyl adipate, which enters the light-removing tower. The operating pressure of the light-removing tower is 10kPaA, the operating temperature of the tower top is 146°C, and the operating temperature of the tower bottom is 180°C. 1550kg / h of light components (30.4% dimethyl adipate, the rest are isomers) are obtained at the top of the tower, and 15758kg / h of bottom liquid is obtained in the bottom of the tower. The tower then enters the heavy-removing tower. The operating pressure of the heavy-removing tower is 10kPaA, the operating temperature of the tower top is 152°C, and the operating temperature of the tower bottom is 182°C. 15442kg / h of dimethyl adipate product (with a purity greater than 99.8%) is obtained at the top of the tower, and 316kg / h of heavy components are obtained in the bottom of the tower.

[0075] The unit consumption of butadiene is 0.349, and the unit consumption of CO is 0.36.

[0076] Example 3

[0077] By adopting the method of Example 2, if no tail gas compressor is used, the feed amount of butadiene is 5399.3 kg / h, the feed amount of CO is 6162 kg / h, and 15442 kg / h of dimethyl adipate product can be obtained.

[0078] The unit consumption of butadiene is 0.39496, and the unit consumption of CO is 0.399.

[0079] It can be seen from this that if there is no exhaust gas compressor, the unit consumption of CO will increase by 0.039. If the price of CO is calculated at 2,400 yuan per ton, the raw material cost of dimethyl adipate will increase by 93.6 yuan per ton.

[0080] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0081] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definition in this specification shall prevail.

[0082] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0083] The endpoints and any values ​​of the scope disclosed in the present application document are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, between the endpoint values ​​of each scope, between the endpoint values ​​of each scope and a separate point value, and between separate point values, one or more new numerical ranges can be combined with each other, and these numerical ranges should be considered as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be considered as specifically disclosed in this article.

[0084] In the context of the present specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

[0085] Moreover, any embodiment described in this document may be freely combined with one or more other embodiments described in this document, and the technical solutions or technical ideas formed thereby are deemed to be part of the original disclosure or original record of the present invention, and should not be regarded as new content that has not been disclosed or anticipated in this document, unless a person skilled in the art considers that the combination is obviously unreasonable.

Claims

1. A method for producing dimethyl adipate, comprising the following steps: (1) subjecting a raw material containing butadiene, CO and methanol to a carbonylation reaction in the presence of a carbonylation catalyst to obtain a reaction mixture containing dimethyl adipate; (2) flashing the reaction mixture containing dimethyl adipate at low pressure to obtain a gas component containing butadiene and CO and a liquid reaction liquid, and returning the gas component containing butadiene and CO to step (1); (3) subjecting the liquid reaction liquid to evaporation treatment, and subjecting the obtained light components to primary condensation and secondary condensation in sequence, to obtain a primary condensate containing dimethyl adipate and a secondary condensate containing methanol and butadiene, respectively, and the secondary condensate is returned to step (1); (4) removing methanol from the primary condensate containing dimethyl adipate to obtain a light component containing methanol and a crude dimethyl adipate product, and the light component is returned to step (1); (5) subjecting the crude dimethyl adipate product to light component removal treatment to remove light component by-products, and then subjecting the crude dimethyl adipate product after light component removal treatment to heavy component removal treatment to obtain a dimethyl adipate product and a heavy component.

2. The production method according to claim 1, characterized in that: In step (1): The carbonylation catalyst is an organic palladium, preferably at least one of palladium acetate and palladium acetylacetonate; and / or, The carbonyl esterification catalyst is used in an amount of 50-4000 ppm, preferably 300-1000 ppm; and / or, The feed molar ratio of methanol to butadiene is (1-10):1, preferably (1.05-1.2):1, and / or the feed molar ratio of CO to butadiene is (1-1.4):1, preferably (1.02-1.05):

1.

3. The production method according to claim 1, characterized in that: In step (1): The carbonyl esterification reaction has an operating temperature of 80-160° C., preferably 90-120° C.; and / or an operating pressure of 1-10 MPaG, preferably 2-5 MPaG; and / or a residence time of 0.5-100 h, preferably 2-12 h.

4. The production method according to claim 1, characterized in that: In step (2): The operating pressure of the low-pressure flash distillation is 0.15-1 MPaG, preferably 0.15-0.5 MPaG; and / or, The low-pressure flash distillation is carried out at the native temperature of the reaction mixture containing dimethyl adipate.

5. The production method according to claim 1, characterized in that: In step (3): The evaporation treatment operating temperature is 80-160°C, preferably 100-120°C; and / or, The outlet temperature of the primary condensation is not higher than 80°C, preferably 40-80°C; and / or, The outlet temperature of the secondary condensation is (-15°C) to (10)°C.

6. The production method according to claim 1, characterized in that: In step (4): The operating pressure of methanol removal is 0.01-0.025 MPaA, preferably 0.018-0.022 MPaA; and / or, the operating temperature of the tower bottom is 120-190°C, preferably 120-180°C; and / or, The temperature at the tower top outlet is 5-30°C, preferably 5-20°C.

7. The production method according to claim 1, characterized in that: In step (5): The conditions for light removal treatment include: an operating pressure of 0.001-0.01 MPaA, preferably 0.0015-0.003 MPaA, and / or a tower top operating temperature of 45-160°C, preferably 45-118°C, and a tower bottom operating temperature of 145-210°C; and / or, The conditions for the deweighting treatment include: an operating pressure of 0.001-0.01 MPaA, preferably 0.0015-0.003 MPaA, and / or a tower top operating temperature of 46-170°C, preferably 46-122°C, and a tower bottom operating temperature of 148-215°C.

8. The production method according to any one of claims 1 to 5, characterized in that: The gas component containing butadiene and CO obtained in step (2) is compressed and returned to step (1); and / or, The uncondensed light components obtained after the secondary condensation in step (3) are discharged; and / or, The light component by-product obtained in step (4) is discharged; and / or, The heavy components obtained after the de-heavy treatment in step (5) are discharged.

9. A production system of dimethyl adipate, preferably used in the production method of dimethyl adipate according to claims 1-8, the production system comprising: Reactor, low-pressure separation tank, evaporation tank, primary condenser, secondary condenser, methanol recovery tower, light removal tower and heavy removal tower; The feed inlet of the reactor is connected to a butadiene raw material source, a CO raw material source and a methanol raw material source respectively. The discharge port of the reactor is connected to the feed port of the low-pressure separation tank; The top discharge port of the low-pressure separation tank is connected to the feed port of the reactor; The bottom discharge port of the low-pressure separation tank is connected to the feed port of the evaporation tank, and the top discharge port of the evaporation tank is connected to the feed port of the primary condenser and the feed port of the secondary condenser in sequence; The liquid outlet of the primary condenser is connected to the feed inlet of the methanol recovery tower, and the liquid outlet of the secondary condenser is connected to the feed inlet of the reactor; the top discharge port of the methanol recovery tower is connected to the feed inlet of the reactor, the bottom discharge port of the methanol recovery tower is connected to the feed inlet of the lightness removal tower, and the bottom discharge port of the lightness removal tower is connected to the feed inlet of the weight removal tower; The tops of the light-removing tower and the heavy-removing tower are respectively provided with discharge ports, and the bottom of the heavy-removing tower is provided with a discharge port.

10. The production system according to claim 9, characterized in that: The production system further comprises a gas compressor, and the top discharge port of the low-pressure separation tank is connected to the feed port of the reactor through the gas compressor; and / or, The top discharge port of the methanol recovery tower and the liquid outlet of the secondary condenser are connected to the feed port of the reactor through part of the same pipeline; and / or, The secondary condenser is provided with an air outlet.

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