An apparatus, method and application for the production of acetoxypropionaldehyde
By employing a method of reusing catalysts and solvents separately in the acetoxypropionaldehyde production process and setting up separation units between reaction units, the complexity of catalyst and solvent recycling was solved, achieving high reaction efficiency and low energy consumption in production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2023-08-16
- Publication Date
- 2026-07-31
AI Technical Summary
In the existing acetoxypropionaldehyde production process, the catalyst and solvent recycling methods are complicated, resulting in high separation process complexity, high energy consumption, low efficiency of the second reaction unit, large equipment scale, and high investment.
By adopting a method of reusing catalysts and solvents separately, a separation unit is set up between the first and second reaction units to separate unreacted materials and recycle catalysts and solvents, reducing the number of equipment, sharing a single separation unit, flexibly adjusting the catalyst ratio, and ensuring the reaction residence time.
It improves reaction efficiency, reduces energy consumption, lowers equipment size and investment, simplifies separation process, and increases recovery rate.
Smart Images
Figure CN119488858B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of acetoxypropionaldehyde preparation technology, specifically relating to an apparatus, method and application for the production of acetoxypropionaldehyde. Background Technology
[0002] Polypropylene terephthalate (PTT), synthesized from 1,3-propanediol, is a novel polyester material that combines the high performance of polyethylene terephthalate (PET) with the easy processability of polybutylene terephthalate (PBT). Currently mature industrial processes all have their own drawbacks. The acrolein hydration hydrogenation process developed by Evonik (formerly Degussa) in Germany uses highly toxic, flammable, and explosive acrolein, which is difficult to store and transport, and is also expensive and hard to obtain. Shell's hydroformylation of ethylene oxide (EO) requires high-pressure equipment, is technically challenging, has a complex catalytic system, is demanding and unstable, and the reaction is difficult to control. DuPont's bio-enzyme catalysis method suffers from low production efficiency and complex purification processes. Therefore, processes for synthesizing propylene glycol and hydroxypropionic acid compounds using vinyl acetate hydroformylation as a key step have been extensively studied in recent years, and the preparation technology of its catalysts is becoming increasingly mature. In this process, vinyl acetate is first hydroformylated to produce the intermediate product acetoxypropanal, then hydrogenated to produce acetoxypropanol, and then hydrolyzed to obtain 1,3-propanediol and 1,2-propanediol, with acetic acid as a byproduct.
[0003] In this process, the hydroformylation of vinyl acetate to prepare aldehydes is the key synthetic step. To improve the conversion rate of olefins, this reaction generally uses two or more reactors in series. This method allows the unconverted raw materials or solutions containing raw materials from the first reaction unit to co-enter the second reaction unit with the syngas to continue the reaction, ensuring residence time and improving the overall conversion rate of vinyl acetate. This method is mentioned in patents CN102826973A, CN86101063A, and US5105018A. In the above patents, the catalyst is often recycled in solution form, usually involving the use of solvent. In this invention, the catalyst and solvent are recycled separately. Inert solvents or products can be used as solvents. Moreover, using products as solvents can reduce the complexity of subsequent separation processes, reduce energy consumption, and improve recovery rate. The method provided by this invention allows two reaction units to share a single separation unit, reducing the number of equipment, shrinking equipment size, and saving investment. Summary of the Invention
[0004] This invention provides an apparatus and method for producing acetoxypropionaldehyde, which employs a method of reusing catalyst and solvent separately. An inert solvent or the product can be used as the solvent. A separation unit is set between the first reaction unit and the second reaction unit to separate the liquid stream obtained from the first reaction unit, separating unreacted materials to continue the reaction, thereby improving the reaction efficiency.
[0005] One objective of this invention is to provide an apparatus for producing acetoxypropionaldehyde, comprising a first reaction unit and a second reaction unit, wherein a first separation unit, a second separation unit, and a third separation unit are sequentially connected by pipelines between the first reaction unit and the second reaction unit, wherein the first reaction unit has a circulation branch on its liquid phase outlet pipeline connected to the first separation unit and connected to the liquid phase inlet of the first reaction unit, the second reaction unit has a pipeline on its liquid phase outlet connected to the first separation unit, and the liquid phase outlet of the second separation unit has pipelines connected to both the first reaction unit and the second reaction unit.
[0006] According to the present invention, in the acetoxypropionaldehyde production apparatus:
[0007] The first reaction unit can be any synthesis reactor known in the art. The first reaction unit is also provided with a raw material inlet, a synthesis gas inlet, a gas phase outlet, a liquid phase outlet, and an optional hydrogen inlet. Preferably, in the first reaction unit, the gas phase outlet is connected to the material inlet of the first separation unit by a pipeline. The first reaction unit is also provided with a cooling system, preferably a cooling coil.
[0008] The first separation unit is also provided with a gas phase outlet and a liquid phase outlet. The liquid phase outlet is connected to the material inlet of the second separation unit by a pipeline. The first separation unit can be any gas-liquid separator known in the art, as long as it can effectively separate the non-condensable gas component and the liquid phase component. For example, it can be any vacuum flash vapor-liquid separator or a combination thereof.
[0009] The second separation unit is further provided with an oxidation gas inlet for introducing oxidation gas into the second separation unit to cause the catalyst to precipitate; the second separation unit is also provided with a gas phase outlet, a catalyst outlet, and a solvent outlet; preferably, in the second separation unit, the gas phase outlet is connected to the material inlet of the third separation unit by a pipeline, the catalyst outlet is connected to the first reaction unit and the second reaction unit by a pipeline, and the solvent outlet is connected to the first reaction unit and the second reaction unit by a pipeline; the catalyst pipeline and solvent pipeline provided in the second separation unit are used to circulate the catalyst and solvent to the first reaction unit and the second reaction unit respectively, realizing the recycling of the catalyst and solvent; the second separation unit can be a combination of various separation equipment known in the art, for example, it can be a centrifugal separator, a tower separator, or a combination thereof;
[0010] The third separation unit is further provided with an unreacted stream outlet, an acetoxypropionaldehyde crude product outlet, and a light component outlet; preferably, in the third separation unit, the unreacted stream outlet is connected to the material inlet of the second reaction unit by a pipeline; the third separation unit can be a combination of various separation devices known in the art, as long as it can separate the unreacted stream, crude product, and light component. For example, the third separation unit can be a tower separation device, which can be a single separation tower or two or more separation towers connected in series;
[0011] The second reaction unit can be any synthesis reactor known in the art. The second reaction unit is also provided with a synthesis gas inlet, an optional hydrogen inlet, a gas phase outlet, and a liquid phase outlet. The gas phase outlet and the liquid phase outlet are respectively connected to the first separation unit by pipelines. The second reaction unit is provided with a cooling system, preferably a jacketed cooling system.
[0012] The second objective of this invention is to provide a method for producing acetoxypropionaldehyde, which is implemented in the aforementioned acetoxypropionaldehyde production apparatus.
[0013] According to the present invention, the method for producing acetoxypropional includes: reacting raw materials, synthesis gas, catalyst, and solvent in a first reaction unit; dividing the resulting liquid phase component into two parts, one part being recycled back to the first reaction unit, and the other part being sequentially sent to a first separation unit, a second separation unit, and a third separation unit for separation; sending the unreacted stream obtained after separation to the second reaction unit for further reaction; and sending the gaseous and liquid phase components obtained from the reaction to the first separation unit respectively. Further, the production method specifically includes the following steps:
[0014] 1) Vinyl acetate, catalyst, synthesis gas S1, and solvent are fed into the first reaction unit for contact reaction, and the gas phase G1 obtained after the reaction is sent into the first separation unit.
[0015] 2) The liquid phase component L1 obtained after the reaction in the first reaction unit is divided into two parts. One part, liquid phase component L1-1, is recycled to the first reaction unit, and the other part, liquid phase component L1-2, is sent to the first separation unit. The separated gas phase component G2 is discharged, and the liquid phase component L2 continues to enter the second separation unit.
[0016] 3) In the second separation unit, gaseous component G3, catalyst and solvent are separated under the action of oxidizing gas; then gaseous component G3 is sent to the third separation unit to separate unreacted stream G4, light component and crude acetoxypropionaldehyde product; the catalyst separated in the second separation unit is recycled to the first reaction unit and the second reaction unit, and the solvent separated is recycled to the first reaction unit and the second reaction unit.
[0017] 4) The unreacted stream G4 and syngas S2 are fed into the second reaction unit for contact reaction, and the gas phase component G5 and liquid phase component L5 obtained from the reaction are fed into the first separation unit respectively.
[0018] According to the present invention, in step 1) of the method for producing acetoxypropionaldehyde:
[0019] The syngas S1 can be any type of syngas available in the art. For example, the syngas S1 is a gaseous component containing hydrogen and carbon monoxide. Preferably, the molar ratio of hydrogen to carbon monoxide in the syngas S1 is (0.5-5.5):1, and more preferably (0.5-3):1. In step 1) above, during continuous industrial production, hydrogen is optionally introduced into the first reaction unit according to the composition of the syngas, in order to adjust the ratio of hydrogen to carbon monoxide in the syngas to be within the above range.
[0020] The molar ratio of vinyl acetate to syngas S1 is 1:(1-21), preferably 1:(1-10), wherein the molar amount of syngas S1 is calculated as the total molar amount of hydrogen and carbon monoxide therein.
[0021] The catalyst is selected from at least one of compounds containing the metallic component cobalt, and can be a cobalt compound and / or complex commonly used in the art; preferably, the catalyst is cobalt octacarbonyl; the amount of the catalyst can be within a range commonly used in the art, for example, in molar amounts, the amount of the catalyst is 0.3 to 10 mol% of vinyl acetate, preferably 0.5 to 5 mol%.
[0022] The solvent is selected from at least one of aromatic solvents and acyloxypropionates, preferably from at least one of toluene, o-dichlorobenzene, and acetoxypropionates. According to the present invention, the solvent can be an inert medium such as toluene or o-dichlorobenzene, or a solvent containing acetoxypropionates, such as 3-acetoxypropionate, or a mixture containing 2-acetoxypropionate and 3-acetoxypropionate, wherein the mixture containing 2-acetoxypropionate and 3-acetoxypropionate can be the crude product of the hydroformylation reaction. According to a specific embodiment of the present invention, the solvent is most preferably a solvent containing acetoxypropionates (3-acetoxypropionate, or a mixture containing 2-acetoxypropionate and 3-acetoxypropionate).
[0023] The catalyst and solvent can be added to the reaction system in a mixed form, wherein the content of the catalyst can be varied within a wide range. Preferably, based on a total catalyst and solvent content of 100 wt%, the catalyst is 1 to 30 wt% of the total catalyst and solvent content, and more preferably 10 to 20 wt%.
[0024] The reaction conditions of the first reaction unit are: reaction temperature of 50-150℃, reaction pressure of 0.5-8MPa, and reaction residence time of 30-180min; preferably, the reaction temperature is 80-130℃, the reaction pressure is 1-7MPa, and the reaction residence time is 30-120min.
[0025] According to the present invention, in step 2) of the method for producing acetoxypropionaldehyde:
[0026] The liquid phase component L1 obtained from the first reaction unit includes reaction products 2-acetoxypropanal and 3-acetoxypropanal, catalyst, solvent, and unreacted vinyl acetate, etc., wherein the liquid phase product L1-1 recycled to the first reaction unit accounts for 8-90% of the liquid phase component L1, preferably 10-50%; preferably, the liquid phase component L1-2 is cooled and then recycled to the first reaction unit to control the reaction temperature of the first reaction unit; further, the temperature of the liquid phase component L1-2 after cooling is 25-90°C, preferably 25-80°C;
[0027] The operating conditions of the first separation unit are not particularly limited, and commonly used separation conditions in the art can be adopted, such as flash evaporation at a pressure of 0.5 to 2.5 MPa, cooling separation at 45 to 80°C, or a combination thereof.
[0028] According to the present invention, in step 3) of the method for producing acetoxypropionaldehyde:
[0029] In the second separation unit, the oxidizing gas is an oxygen-containing gas atmosphere. Preferably, the oxygen content in the oxidizing gas is 0.5-25 wt%. Specifically, it can be air or a mixture of air and oxygen. An excess of oxidizing gas is introduced into the second separation unit to precipitate the catalyst and separate it from the product system. The amount of oxidizing gas is not particularly limited, as long as it is sufficient to completely precipitate and recover the catalyst. For example, the molar ratio of oxidizing gas S3 to catalyst is 1-99, preferably 1-90.
[0030] The operation process of the second separation unit is not particularly limited, and common separation methods in the art can be used. Specifically, the liquid phase component L2 enters the second separation unit, and excess oxidizing gas is introduced to cause the catalyst to precipitate. After filtration and separation, the remaining liquid phase material is directly separated or separated by a separation tower to obtain the catalyst, solvent and crude product stream. The separation tower equipment can be common separation tower equipment and operating conditions in the art, for example, pressure of 5 to 201 kPa, number of trays of 5 to 40, and reflux ratio of 0.1 to 10.
[0031] The third separation unit can be any separation equipment and combination known in the art, as long as it can separate the crude acetoxypropionaldehyde product, the light components, and the stream containing unreacted materials. For example, a separation tower can be used, and the operating conditions of the separation tower can be any conditions known in the art. Preferably, the top temperature of the separation tower is 80-120°C, the bottom temperature is 90-150°C, the pressure is 10-200 kPa (g), the number of trays is 5-40, and the reflux ratio is 0.1-10. The obtained crude acetoxypropionaldehyde product includes 2-acetoxypropionaldehyde and 3-acetoxypropionaldehyde, and the light components mainly contain acetic acid and ethyl acetate.
[0032] The catalyst and solvent obtained from the second separation unit are recycled to the first and second reaction units, respectively. The ratio of recycled catalyst to solvent is not particularly limited and can be adjusted within a wide range. Preferably, the catalyst recycled to the first reaction unit is 50-99% of the total catalyst obtained from the second separation unit, preferably 60-99%; the catalyst recycled to the second reaction unit is 1-50% of the total catalyst obtained from the second separation unit, preferably 1-40%; the solvent recycled to the first reaction unit is 50-99% of the total solvent obtained from the second separation unit, preferably 60-99%; and the solvent recycled to the second reaction unit is 1-50% of the total solvent obtained from the second separation unit, preferably 1-40%. The recycled catalyst and solvent can be partially or completely returned to the first and second reaction units according to actual needs, with the remaining portion being discharged for recovery.
[0033] According to the present invention, in step 4) of the method for producing acetoxypropionaldehyde:
[0034] The syngas S2 can be any type of syngas available in the art. For example, the syngas S2 is a gaseous component containing hydrogen and carbon monoxide. Preferably, the molar ratio of hydrogen to carbon monoxide in the syngas S2 is (0.5-5.5):1, and more preferably (0.5-3):1. In the continuous industrial production process, hydrogen is optionally introduced into the second reaction unit according to the composition of the syngas introduced, in order to adjust the ratio of hydrogen to carbon monoxide in the syngas within the above range.
[0035] The molar ratio of the synthesis gas S2 to the vinyl acetate in the unreacted stream G4 is (1-21):1, preferably (1-10):1, wherein the molar amount of the synthesis gas S2 is calculated as the total molar amount of hydrogen and carbon monoxide therein.
[0036] In the second reaction unit, the amount of catalyst used is 0.3 to 20 wt% of vinyl acetate in the unreacted stream G4, preferably 1 to 18 wt%.
[0037] The reaction conditions of the second reaction unit are: reaction temperature of 50-150℃, reaction pressure of 0.5-8MPa, and reaction residence time of 30-180min; preferably, the reaction temperature is 80-130℃, the reaction pressure is 1-7MPa, and the reaction residence time is 30-120min.
[0038] In the second reaction unit, the obtained gaseous and liquid products are sent to the first separation unit to repeat the above separation operation, and the catalyst and solvent are recovered and recycled to obtain crude acetoxypropionaldehyde product.
[0039] The method for producing acetoxypropionaldehyde provided by this invention is suitable for continuous production processes. In the initial reaction, an appropriate amount of catalyst and solvent are added to the first reaction unit. In the continuous production process, vinyl acetate and syngas are added to the first and second reaction units in a timely manner. By controlling the circulating ratio of catalyst and solvent during the separation process, the ratio of vinyl acetate to catalyst in the first and second reaction units is kept within an appropriate range to ensure the reaction residence time and improve the reaction efficiency.
[0040] The third objective of this invention is to apply the above-mentioned acetoxypropionaldehyde production apparatus or the above-mentioned acetoxypropionaldehyde production method to the preparation of acetoxypropionaldehyde.
[0041] Because the liquid phase obtained from the first reaction unit contains unconverted raw materials and a large amount of acetoxypropionaldehyde product, it reduces the efficiency of the second reaction unit. This invention incorporates a separation unit between the first and second reaction units to separate the crude product, light components, and the stream containing unreacted materials. The unreacted materials are then fed back into the second reaction unit. Furthermore, the catalyst and solvent obtained during the separation process are recycled back to the first and second reaction units, respectively. This method effectively improves the reaction efficiency of the second reaction unit, reduces the size of the second reaction unit, reduces side reactions, and reduces energy consumption. When the product is used as a solvent, it reduces the complexity of subsequent separation processes, reduces energy consumption, and increases the recovery rate. Moreover, it allows for flexible control of the catalyst ratio between the first and second reaction units, ensuring sufficient reaction residence time and efficiency.
[0042] This invention, by setting up multiple reaction units and gas-liquid separation units, rationally arranging the material flow direction, and flexibly adjusting the catalyst ratio of each reaction unit, saves energy consumption, effectively improves the reaction efficiency of the reaction units, reduces the size of the reaction unit equipment, and reduces side reactions. At the same time, two reaction units can share a set of separation units, reducing the number of equipment and shrinking the equipment size, thus saving investment. Attached Figure Description
[0043] Figure 1 This is a schematic diagram of the hydroformylation reaction apparatus used in an embodiment of the present invention.
[0044] Explanation of reference numerals in the attached figures:
[0045] 1-First reaction unit, 2-Second reaction unit, 3-First separation unit, 4-Second separation unit, 5-Gas phase component G1 pipeline, 6-Gas phase component G5 pipeline, 7-Synthesis gas S1 pipeline, 8-Vinyl acetate pipeline, 9-Hydrogen pipeline, 10-Synthesis gas S2 pipeline, 11-Solvent circulation pipeline, 12-Oxidizing gas pipeline, 13-Liquid phase component L1-1 circulation pipeline, 14-Third separation unit, 15-Liquid phase component L5 pipeline, 16-Light component discharge pipeline, 17-Crude product discharge pipeline, 18-Catalyst circulation pipeline, 19-Unreacted stream G4 pipeline. Detailed Implementation
[0046] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.
[0047] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.
[0048] The embodiments of the present invention employ an acetoxypropionaldehyde production device, such as... Figure 1As shown, the system includes a first reaction unit 1 and a second reaction unit 2. Between the first reaction unit 1 and the second reaction unit 2, there are a first separation unit 3, a second separation unit 4, and a third separation unit 14 connected in sequence by pipelines. The first reaction unit 1 has a circulation branch on the liquid phase L1 outlet pipeline connected to the first separation unit 3, which is connected to the liquid phase inlet of the first reaction unit 1. The second reaction unit 2 has a pipeline 15 at the liquid phase outlet connected to the first separation unit 3 and a pipeline 6 at the gas phase outlet connected to the first separation unit 3. The second reaction unit 4 has a solvent circulation pipeline 11 and a catalyst circulation pipeline 18 connected to the first reaction unit 1 and the second reaction unit 2, respectively. The first reaction unit 1 is also equipped with a raw material inlet 8, a synthesis gas S1 inlet 7, a gas phase G1 outlet, a liquid phase L1 outlet, and a hydrogen inlet 9; the first separation unit 3 is also equipped with a gas phase G2 outlet and a liquid phase L2 outlet; the second separation unit 4 is also equipped with an oxidizing gas inlet 12, a gas phase G3 outlet, a catalyst outlet 18, and a solvent outlet 11; the third separation unit 14 is also equipped with an unreacted stream G4 outlet, an acetoxypropionaldehyde crude product outlet 17, and a light component outlet 16; the unreacted stream G4 outlet is connected to the material inlet of the second reaction unit 2 by a pipeline 19; the second reaction unit 2 is also equipped with a synthesis gas S2 inlet 10, a hydrogen inlet 9, a gas phase G5 outlet, and a liquid phase L5 outlet.
[0049] Example 1
[0050] Vinyl acetate, syngas S1, and catalyst solution (solvent is 3-acetoxypropionaldehyde, the amount of cobalt compound in the solution is 11.96% based on cobalt octacarbonyl) are fed into the first reaction unit 1. The feed rate of vinyl acetate is 2829 kg / h, the feed rates of catalyst solution and solvent are 636.69 kg / h and 86.53 kg / h, respectively, and the feed rate of syngas S1 is 1028 kg / h (the molar ratio of hydrogen to carbon monoxide in the syngas is 1.02:1). The feed molar ratio of syngas S1 to vinyl acetate in the reactor is maintained at approximately 2.13:1. After the reaction, the gas phase G1 is sent to the first separation unit 3. A portion of the liquid phase L1-1 at the bottom of the reactor is cooled to 45°C and returned to the first reaction unit 1, while the other portion L1-2 is sent to the second reaction unit 2. The ratio of the liquid phase L1-1 returned to the first reaction unit 1 to the total liquid phase L1 collected from the bottom of the first reaction unit is 0.1.
[0051] In the first separation unit 3, the components including liquid phase components L1-2, gas phase G1, and gas phase G5 are depressurized to 1.0 MPa and then flash-separated. The resulting gas phase G2 is discharged, and the remaining liquid phase component L2 is sent to the second separation unit 4. Air is introduced into the second separation unit 4 at a rate of 100 kg / h, and the catalyst and liquid phase are separated by centrifugation. The catalyst is recycled back to the first and second reaction units at rates of 86.53 kg / h and 14.09 kg / h, respectively. The liquid phase is separated by a distillation column, and 740.33 kg of bottom feed is used as solvent and recycled back to the first reaction unit at a rate of 636.69 kg / h and to the second reaction unit at a rate of 103.65 kg / h. The second separation unit 4 (distillation column) has a top temperature of 97.7℃, a bottom temperature of 123.4℃, a pressure of 30 kPa, 23 trays, and a top reflux ratio of 1, allowing the remaining gas phase G3 to enter the third separation unit 14.
[0052] The third separation unit 14 consists of two separation towers. Separation tower one has a top temperature of 53.6℃, a bottom temperature of 103.8℃, a pressure of 30kPa, and 18 trays. Unreacted reactants are refluxed at the top of the tower at a reflux ratio of 8, allowing unreacted vinyl acetate and other substances to be collected from the top and fed into separation tower two. Separation tower two has a top temperature of 53.6℃, a bottom temperature of 60℃, a pressure of 50kPa, and 22 trays. The top reflux ratio is 5, and 218.5 kg / h of unreacted stream is collected from the top of the tower, while 240 kg / h of light components, mainly containing acetic acid and ethyl acetate, is collected from the bottom of the tower.
[0053] Another stream of syngas S2 (with a hydrogen to carbon monoxide molar ratio of 1.26:1) and unreacted stream G4 from the third separation unit 14 are fed into the second reaction unit 2. The feed rate of unreacted stream G4 is 218.5 kg / h, and the feed rate of syngas S2 is 131 kg / h. The feed molar ratio of syngas S2 to vinyl acetate in unreacted stream G4 in the second reaction unit 2 is maintained at 4.85:1. The liquid product G5467.24 kg / h from the second reaction unit 2 is fed into the first separation unit 3 for combined processing.
[0054] The reaction temperature in the first reaction unit 1 was 109℃ and the pressure was 6.5 MPa. The reaction temperature in the second reaction unit 1 was 115℃ and the pressure was 6.0 MPa. The residence time in the first reaction unit was 60 min, and the residence time in the second reaction unit was 80 min. The conversion rate of vinyl acetate was 99%, and the yield was 87.8%.
[0055] Example 2
[0056] The process flow is the same as in Example 1, except that:
[0057] Vinyl acetate, syngas S1, and catalyst solution (solvent is 3-acetoxypropionaldehyde, the amount of cobalt compound in the solution is 11.21% based on cobalt octacarbonyl) are fed into the first reaction unit 1. The syngas S1 to syngas S1 feed molar ratio in the reactor is maintained at approximately 1.92:1. A portion of the liquid phase L1-1 at the bottom of the reactor in the first reaction unit 1 is cooled to 45°C and returned to the first reaction unit 1, while the other portion L1-2 is sent to the second reaction unit 2. The ratio of the liquid phase L1-1 returned to the first reaction unit 1 to the total liquid phase L1 collected from the bottom of the reactor in the first reaction unit 1 is 0.2.
[0058] The liquid phase component L2 obtained from the first separation unit 3 is fed into the second separation unit 4, where air is introduced at a rate of 200 kg / h. The catalyst and liquid phase are separated by centrifugation. The catalyst is recycled back to the first reaction unit 1 and the second reaction unit 2 at rates of 77.13 kg / h and 12.56 kg / h, respectively. The liquid phase is separated by a distillation column, and 710.27 kg of the bottom feed is recycled back to the first reaction unit at a rate of 610.83 kg / h and the second reaction unit at a rate of 99.44 kg / h. The column top temperature is 97.2℃, the bottom temperature is 123.4℃, the pressure is 30 kPa, the number of trays is 23, and the top reflux ratio is 1, allowing the remaining liquid phase L3 to enter the third separation unit 14.
[0059] In the third separation unit 14, the top temperature of separation tower one is 51.6℃, the bottom temperature is 98.4℃, the pressure is 25kPa, and the number of trays is 18. Unreacted reactants are refluxed at the top of the tower at a reflux ratio of 10, allowing unreacted vinyl acetate and other substances to be collected from the top and sent to separation tower two. Separation tower two has a top temperature of 54.4℃, a bottom temperature of 61.1℃, a pressure of 50kPa, and 23 trays. The top reflux ratio is 5, and the unreacted stream collected at the top is 252.54 kg / h, while the light component mainly containing acetic acid and ethyl acetate is collected at the bottom at 240 kg / h.
[0060] Another stream of syngas S2 (with a hydrogen to carbon monoxide molar ratio of 1.28:1) and unreacted stream G4 from the third separation unit 14 are fed into the second reaction unit 2. The feed rate of unreacted stream G4 is 364.54 kg / h, and the feed rate of syngas S2 is 131 kg / h. The feed molar ratio of syngas S2 to vinyl acetate in unreacted stream G4 in the second reaction unit 2 is maintained at 4.45:1. The liquid product G5495.54 kg / h from the second reaction unit 2 is fed into the first separation unit 3 for combined processing.
[0061] The reaction temperature in the first reaction unit 1 is 105℃ and the pressure is 5.5 MPa, while the reaction temperature in the second reaction unit 2 is 109℃ and the pressure is 6.5 MPa. The conversion rate of vinyl acetate is 99%, and the yield is 88.6%.
[0062] Example 3
[0063] The process flow is the same as in Example 1, except that:
[0064] Vinyl acetate, syngas S1, and catalyst solution (solvent is 3-acetoxypropionaldehyde, the amount of cobalt compound in the solution is 15.51% based on cobalt octacarbonyl) are fed into the first reaction unit 1. The syngas S1 to syngas S1 feed molar ratio in the reactor is maintained at approximately 1.91:1. A portion of the liquid phase L1-1 at the bottom of the reactor in the first reaction unit 1 is cooled to 45°C and returned to the first reaction unit 1, while the other portion L1-2 is sent to the second reaction unit 2. The ratio of the liquid phase L1-1 returned to the first reaction unit 1 to the total liquid phase L1 collected from the bottom of the reactor in the first reaction unit 1 is 0.5.
[0065] The liquid phase component L2 obtained from the first separation unit 3 is fed into the second separation unit 4, where air is introduced at a rate of 250 kg / h. The catalyst and liquid phase are separated by centrifugation. The catalyst is recycled back to the first reaction unit 1 and the second reaction unit 2 at rates of 106.69 kg / h and 17.37 kg / h, respectively. The liquid phase is separated by a distillation column, and 675.9 kg of the bottom feed is recycled back to the first reaction unit at a rate of 581.27 kg / h and the second reaction unit at a rate of 94.63 kg / h. The column top temperature is 98.1℃, the bottom temperature is 123.4℃, the pressure is 30 kPa, the number of trays is 23, and the top reflux ratio is 1, allowing the remaining liquid phase L3 to enter the third separation unit 14.
[0066] In the third separation unit 14, the top temperature of separation tower one is 55℃, the bottom temperature is 98.4℃, the pressure is 30kPa, and the number of trays is 18. Unreacted reactants are refluxed at the top of the tower at a reflux ratio of 10, so that unreacted vinyl acetate and other substances are collected from the top of the tower and sent to separation tower two. The top temperature of separation tower two is 54.4℃, the bottom temperature is 61℃, the pressure is 50kPa, the number of trays is 23, the top reflux ratio is 7, the unreacted stream collected from the top of the tower is 145.89 kg / h, and the light component mainly containing acetic acid and ethyl acetate is collected from the bottom of the tower at 240 kg / h.
[0067] Another stream of syngas S2 (with a hydrogen to carbon monoxide molar ratio of 1.28:1) and unreacted stream G4 from the third separation unit 14 are fed into the second reaction unit 2. The feed rate of unreacted stream G4 is 145.89 kg / h, and the feed rate of syngas S2 is 131 kg / h. The feed molar ratio of syngas S2 to vinyl acetate in unreacted stream G4 in the second reaction unit 2 is maintained at 8.1:1. The liquid product G5 from the second reaction unit 2 is fed into the first separation unit 3 for combined processing.
[0068] The reaction temperature in the first reaction unit 1 is 101℃ and the pressure is 6.0 MPa, while the reaction temperature in the second reaction unit 2 is 107℃ and the pressure is 6.5 MPa. The conversion rate of vinyl acetate is 99%, and the yield is 88.6%.
[0069] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.
Claims
1. A method for producing acetoxypropionaldehyde, the method specifically comprising the following steps: 1) Vinyl acetate, catalyst, syngas S1, and solvent are fed into the first reaction unit for contact reaction, and the gas phase G1 obtained after the reaction is fed into the first separation unit; the molar ratio of hydrogen to carbon monoxide in the syngas S1 is (0.5~5.5):1, and the molar ratio of vinyl acetate to syngas S1 is 1:(1~21). 2) The liquid phase component L1 obtained after the reaction in the first reaction unit is divided into two parts. One part, liquid phase component L1-1, is recycled back to the first reaction unit, and the other part, liquid phase component L1-2, is sent to the first separation unit. The separated gas phase component G2 is discharged, and the liquid phase component L2 continues to enter the second separation unit. The liquid phase product L1-1 recycled back to the first reaction unit accounts for 10-50% of the liquid phase component L1. 3) In the second separation unit, gaseous components G3, catalyst, and solvent are separated under the action of oxidizing gas; Then, the gaseous component G3 is sent to the third separation unit to separate unreacted stream G4, light components, and crude acetoxypropionaldehyde product. The catalyst obtained from the second separation unit is recycled to the first and second reaction units, and the solvent obtained from the separation unit is also recycled to the first and second reaction units. 4) The unreacted stream G4 and the syngas S2 are fed into the second reaction unit for contact reaction, and the gaseous component G5 and the liquid component L5 obtained from the reaction are respectively fed into the first separation unit; the molar ratio of hydrogen to carbon monoxide in the syngas S2 is (0.5~5.5):1, and the molar ratio of syngas S2 to vinyl acetate in the unreacted stream G4 is (1~21):
1.
2. The production method according to claim 1, characterized by, The method for producing acetoxypropionaldehyde is implemented in an acetoxypropionaldehyde production apparatus, which includes a first reaction unit and a second reaction unit. Between the first and second reaction units are a first separation unit, a second separation unit, and a third separation unit connected sequentially by pipelines. The first reaction unit has a circulation branch on its liquid phase outlet pipeline connected to the first separation unit, which is then connected to the liquid phase inlet of the first reaction unit. The second reaction unit has a pipeline at its liquid phase outlet connected to the first separation unit, and the liquid phase outlet of the second separation unit has pipelines connecting to both the first and second reaction units. The second separation unit also has an oxidation gas inlet. The second separation unit is further provided with a gas phase outlet, a catalyst outlet, and a solvent outlet. The gas phase outlet is connected to the material inlet of the third separation unit via a pipeline. The catalyst outlet is connected to the first reaction unit and the second reaction unit via a pipeline. The solvent outlet is connected to the first reaction unit and the second reaction unit via a pipeline. The third separation unit is further provided with an unreacted stream outlet, an acetoxypropionaldehyde crude product outlet, and a light component outlet. The unreacted stream outlet is connected to the material inlet of the second reaction unit via a pipeline. The second reaction unit is further provided with a syngas inlet, an optional hydrogen inlet, a gas phase outlet, and a liquid phase outlet. The gas phase outlet and the liquid phase outlet are respectively connected to the first separation unit via pipelines.
3. The production method according to claim 2, characterized in that, The first reaction unit is further provided with a raw material inlet, a synthesis gas inlet, a gas phase outlet, a liquid phase outlet, and an optional hydrogen inlet; and / or, The first reaction unit is also provided with a cooling system; and / or, The first separation unit is further provided with a gas phase outlet and a liquid phase outlet, the liquid phase outlet being connected by a pipeline to the material inlet of the second separation unit; and / or, The second reaction unit is equipped with a cooling system.
4. The production method according to claim 3, characterized in that, In the first reaction unit, the gas phase outlet is connected to the material inlet of the first separation unit via a pipeline; and / or, The cooling system of the first reaction unit is a cooling coil; and / or, The cooling system of the second reaction unit is a jacketed cooling system.
5. The production method according to claim 1, characterized in that, In step 1): The catalyst is selected from at least one of compounds containing the metallic component cobalt; and / or, The amount of catalyst used, in molar amounts, is 0.3~10 mol% of vinyl acetate; and / or, The solvent is selected from at least one of aromatic solvents and acyloxy aldehyde compounds; and / or, Based on a total catalyst and solvent content of 100 wt%, the catalyst comprises 1-30 wt% of the total catalyst and solvent content; and / or, The reaction conditions for the first reaction unit are: a reaction temperature of 50~150 ℃ and a reaction pressure of 0.5~8 MPa.
6. The production method according to claim 5, characterized in that, In step 1): The molar ratio of vinyl acetate to syngas S1 is 1:(1~10); and / or, The catalyst is cobalt octacarbonyl; and / or, The amount of catalyst used, in molar amounts, is 0.5-5 mol% of vinyl acetate; and / or, The solvent is selected from at least one of toluene, o-dichlorobenzene, and acetoxypropionaldehyde compounds; and / or, Based on a total catalyst and solvent content of 100 wt%, the catalyst comprises 10-20 wt% of the total catalyst and solvent content; and / or, The reaction conditions for the first reaction unit are: a reaction temperature of 80~130 ℃ and a reaction pressure of 1~7 MPa.
7. The production method according to claim 1, characterized in that, In step 3): In the second separation unit, the oxidizing gas is an oxygen-containing gaseous atmosphere; and / or, The catalyst recycled to the first reaction unit is 50-99% of the total catalyst obtained from the second separation unit; and / or, The catalyst recycled to the second reaction unit is 1-50% of the total catalyst obtained from the second separation unit; and / or, The solvent recycled to the first reaction unit is 50-99% of the total solvent obtained from the second separation unit; and / or, The solvent recycled to the second reaction unit is 1 to 50% of the total amount of solvent obtained from the second separation unit.
8. The production method according to claim 7, characterized in that, In step 3): In the second separation unit, the oxygen content in the oxidizing gas is 0.5~25wt%; and / or, The catalyst recycled to the first reaction unit is 60-99% of the total catalyst obtained from the second separation unit; and / or, The catalyst recycled to the second reaction unit is 1-40% of the total catalyst obtained from the second separation unit; and / or, The solvent recycled to the first reaction unit is 60-99% of the total solvent obtained from the second separation unit; and / or, The solvent recycled to the second reaction unit is 1 to 40% of the total amount of solvent obtained from the second separation unit.
9. The production method according to claim 1, characterized in that, In step 4): In the second reaction unit, the amount of catalyst used is 0.3~20 wt% of vinyl acetate in the unreacted stream G4; and / or, The reaction conditions for the second reaction unit are: a reaction temperature of 50~150 ℃ and a reaction pressure of 0.5~8 MPa.
10. The production method according to claim 9, characterized in that, In step 4): The molar ratio of the synthesis gas S2 to the vinyl acetate in the unreacted stream G4 is (1~10):1; and / or, In the second reaction unit, the amount of catalyst used is 1-18 wt% of vinyl acetate in the unreacted stream G4; and / or, The reaction conditions for the second reaction unit are: reaction temperature of 80~130 ℃ and reaction pressure of 1~7 MPa.
11. A method for producing acetoxypropionaldehyde according to any one of claims 1 to 10, and its application in the preparation of acetoxypropionaldehyde.