Production method for producing DEA and co-producing OEA
Through the preparation and application of modified supported catalysts, the problems of low raw material utilization, high production costs and serious environmental pollution in traditional DEA and OEA production methods are solved, and efficient co-production and environmentally friendly production of DEA and OEA are achieved.
Patent Information
- Application Number
- CN202510239682.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2025-06-27
AI Technical Summary
Traditional DEA and OEA production methods have problems such as low raw material utilization rate, high production costs, and serious environmental pollution. The catalyst activity is not high enough, the selectivity is not ideal, and the stability is poor, resulting in increased production costs and environmental pollution.
Using the preparation method of a modified supported catalyst, the catalyst with a high specific surface area and multi-stage pore structure is formed by reacting tetraethyl orthosilicate, aluminum isopropoxide and isopropanol with bis(2-hydroxyethyl)methyltetradecyl chloride quaternary ammonium salt and tetramethyl ammonium fluoride in specific proportions and conditions, and the performance of the catalyst is improved by alkali solution etching and ammonium molybdate.
It realizes efficient co-production of DEA and OEA, improves raw material utilization and production efficiency, reduces production costs and environmental pollution, and the modified catalyst has the characteristics of high conversion and easy recycling, and supports multiple reuses.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of OEA production, and specifically to a production method for co-producing OEA in DEA production. Background Art
[0002] Traditional production methods of 2,6 - diethylaniline (DEA) and o - ethylaniline (OEA) often have problems such as low raw material utilization rate, high production cost, and serious environmental pollution. These problems limit the further development of traditional production technologies and also prompt researchers to continuously explore new production technologies. The emergence of co - production technology aims to solve these problems by optimizing the production process, improving raw material utilization rate, and reducing production costs.
[0003] Co - production technology is a technology for simultaneously producing multiple products in the same set of equipment. In the process of co - producing OEA in DEA production, by adjusting parameters such as reaction conditions and catalyst selection, it is possible to simultaneously generate 2,6 - diethylaniline and 2 - ethylaniline in the same reaction system, optimize the production process, improve raw material utilization rate, reduce production costs, reduce waste emissions, and improve resource utilization rate to reduce environmental pollution. However, some current catalysts may have problems such as insufficient activity, unsatisfactory selectivity, and poor stability, resulting in the need to use a large amount of catalysts in the production process, increasing costs, and frequent catalyst replacement will also affect the continuity of production. At the same time, the recovery and regeneration of catalysts are also a difficult problem, and improper handling will cause resource waste and environmental pollution. Summary of the Invention
[0004] The purpose of the present invention is to provide a production method for co - producing OEA in DEA production to solve the problems existing in the prior art.
[0005] To solve the above - mentioned technical problems, the present invention provides the following technical solution: A production method for co - producing OEA in DEA production, comprising the following steps:
[0006] (1) Preparation of modified supported catalyst: Tetraethyl orthosilicate, aluminum isopropoxide, and isopropanol are dissolved in cyclohexane to form solution A. Bis(2 - hydroxyethyl)methyltetradecylammonium chloride and tetramethylammonium fluoride are dissolved in deionized water to form solution B. Solution A is added to solution B, and stirred at 200 rpm at room temperature for 30 - 40 min, then transferred into a reaction kettle and reacted at 120 °C for 4 - 8 h. The solid is filtered, washed 3 times with deionized water and ethanol, dried in an oven at 50 - 60 °C for 14 - 24 h, and calcined in a calcination furnace for 4 - 8 h to obtain the modified catalyst;
[0007] (2) After etching the modified catalyst with an alkaline solution, it is dispersed in an aqueous ammonium molybdate solution, stirred at 20-30 °C for 24 h, filtered to obtain the solid, and calcined in a calcination furnace for 1-3 h to prepare the modified supported catalyst;
[0008] (3) Alkylation reaction: 50-100 kg of the modified supported catalyst is mixed evenly with 2200-2500 kg of aniline in a synthesis kettle. After reacting at 140 °C - 160 °C for 1 hour, the temperature is raised to 310 °C, the pressure is adjusted to 4.6-5.0 MPa, and 1300 kg - 2300 kg of ethylene is introduced. The reaction lasts for 8-14 h. After the reaction is completed, heating is stopped and the temperature is lowered to 120 °C;
[0009] (4) After filtering the materials in the synthesis kettle, the liquid is transferred to an evaporation kettle, and then the ethylene in the synthesis kettle and the evaporation kettle is recovered. The vacuum pump is turned on and the temperature is raised to 140 °C to distill out the crude products of 2,6-diethylaniline and o-ethylaniline;
[0010] (5) Rectification: Turn on the vacuum pump to separate and refine the crude products of 2,6-diethylaniline and o-ethylaniline.
[0011] Further, the mass ratio of tetraethyl orthosilicate, aluminum isopropoxide, and isopropanol in step (1) is 1:(0.06 - 0.07):(0.2 - 0.3).
[0012] Further, the mass of cyclohexane in step (1) is 8-12 times the mass of tetraethyl orthosilicate.
[0013] Further, the mass ratio of bis(2-hydroxyethyl)methyltetradecylammonium chloride, tetramethylammonium fluoride, and tetraethyl orthosilicate in step (1) is 1:(0.37 - 0.49):(0.14 - 0.22).
[0014] Further, the mass of deionized water in step (1) is 7-10 times the mass of tetraethyl orthosilicate.
[0015] Further, the rate of adding solution A to solution B in step (1) is 5 mL / min.
[0016] Further, the steps of alkaline solution etching in step (2) are as follows: The modified catalyst is dispersed in a 0.4 mol / L sodium hydroxide aqueous solution, stirred at 75-85 °C at 120 rpm for 1-2 h, immediately cooled with an ice-water bath, repeated 3 times, and then stirred at 75-85 °C and 100 rpm in a 2 mol / L ammonium chloride aqueous solution for 30-60 min, repeated 3 times, and calcined in a calcination furnace for 2-4 h.
[0017] Further, the ammonium molybdate content in the ammonium molybdate aqueous solution in step (2) is 5 wt%.
[0018] Further, the temperature of the calcination furnace is 500 - 600 °C.
[0019] Further, after starting the vacuum pump, the vacuum degree is -0.1 to -0.098 MPa.
[0020] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:
[0021] Through the co-production technology, the present invention makes full use of raw materials, reduces waste of raw materials, improves production efficiency, and precisely controls the dosage of the modified supported catalyst and ethylene to ensure the quality stability of the product. At the same time, on the basis of high conversion rate and easy recovery, the modified supported catalyst can be reused multiple times, greatly reducing production costs and realizing green, safe and environmentally friendly production.
[0022] The modified supported catalyst uses bis(2-hydroxyethyl)methyltetradecylammonium chloride and tetramethylammonium fluoride as structure-directing agents, so that the lamellar structure of the catalyst is supported by long-chain organic substances between the layers, forming a stacked and ordered mesoscopic structure to achieve a swelling effect, thereby increasing the contact area between reactants and active sites, and further improving the reaction efficiency. In cooperation with the weak acid sites of tetramethylammonium fluoride, while promoting the reaction, it can also avoid side reactions caused by strong acid sites, improving the selectivity and yield of the target product; then aluminum isopropoxide is added to modify the molecular sieve framework to form hierarchical pores inside the particles, preparing a layered porous molecular sieve with a high specific surface area and a large pore volume, enhancing the catalytic effect and providing a growth environment for subsequent loading; then ammonium molybdate is used for loading to form a hierarchical pore structure, providing a more unobstructed diffusion channel for reactants and products, and further improving the catalytic reaction efficiency. Specific Embodiments
[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0024] Example 1
[0025] (1) Preparation of modified supported catalyst: Tetraethyl orthosilicate, aluminum isopropoxide and isopropanol were dissolved in cyclohexane at a mass ratio of 1:0.06:0.2, and the amount of cyclohexane was 8 times the mass of tetraethyl orthosilicate to form solution A. Bis(2-hydroxyethyl)methyltetradecylammonium chloride at 0.37 times the mass of tetraethyl orthosilicate and tetraethylammonium fluoride at 0.14 times the mass of tetraethyl orthosilicate were dissolved in deionized water at 7 times the mass of tetraethyl orthosilicate to form solution B. Solution A was added to solution B at a rate of 5 mL / min, and stirred at 200 rpm for 30 min at room temperature. Then it was transferred into a reaction kettle and reacted at 120 °C for 4 h. The solid was collected by filtration, washed 3 times with deionized water and ethanol, dried in an oven at 50 °C for 14 h, and calcined in a calcination furnace at 500 °C for 4 h to obtain the modified catalyst;
[0026] (2) The modified catalyst was dispersed in 0.4 mol / L sodium hydroxide aqueous solution, stirred at 120 rpm at 75 °C for 1 h, and immediately cooled with an ice-water bath, repeated 3 times. Then it was stirred at 75 °C and 100 rpm in 2 mol / L ammonium chloride aqueous solution for 30 min, repeated 3 times, calcined in a calcination furnace at 500 °C for 2 h, and dispersed in ammonium molybdate aqueous solution with 5 wt% ammonium molybdate content, stirred at 20 °C for 24 h. The solid was collected by filtration and calcined in a calcination furnace at 500 °C for 1 h to obtain the modified supported catalyst;
[0027] (3) Alkylation reaction: 50 kg of the modified supported catalyst was mixed evenly with 2200 kg of aniline in a synthesis kettle. After reacting at 140 °C for 1 h, the temperature was raised to 310 °C, the pressure was adjusted to 4.6 MPa, and 1300 kg of ethylene was introduced and reacted for 8 h. After the reaction, heating was stopped and the temperature was lowered to 120 °C;
[0028] (4) After filtering the materials in the synthesis kettle, the liquid was transferred to an evaporation kettle, and then ethylene in the synthesis kettle and evaporation kettle was recovered. The vacuum pump was turned on to a vacuum degree of -0.1 MPa, and the temperature was raised to 140 °C to distill out the crude products of 2,6 - diethylaniline and o - ethylaniline;
[0029] (5) Rectification: The vacuum pump was turned on to a vacuum degree of -0.1 MPa to separate and refine the crude products of 2,6 - diethylaniline and o - ethylaniline.
[0030] Example 2
[0031] (1) Preparation of modified supported catalyst: Tetraethyl orthosilicate, aluminum isopropoxide and isopropanol were dissolved in cyclohexane with a mass ratio of 1:0.07:0.25 and 10 times the mass of tetraethyl orthosilicate to form solution A. Bis(2-hydroxyethyl)methyltetradecylammonium chloride with 0.43 times the mass of tetraethyl orthosilicate and tetraethylammonium fluoride with 0.18 times the mass of tetraethyl orthosilicate were dissolved in deionized water with 8 times the mass of tetraethyl orthosilicate to form solution B. Solution A was added to solution B at a rate of 5 mL / min and stirred at 200 rpm at room temperature for 35 min. Subsequently, it was transferred into a reaction kettle and reacted at 120 °C for 6 h. The solid was filtered out, washed 3 times with deionized water and ethanol, dried in an oven at 55 °C for 19 h, and calcined in a calcination furnace at 550 °C for 6 h to obtain the modified catalyst;
[0032] (2) The modified catalyst was dispersed in a 0.4 mol / L aqueous sodium hydroxide solution and stirred at 120 rpm at 80 °C for 1.5 h, then immediately cooled with an ice-water bath, and this was repeated 3 times. Then it was stirred at 80 °C and 100 rpm in a 2 mol / L aqueous ammonium chloride solution for 45 min, and this was repeated 3 times. It was calcined in a calcination furnace at 550 °C for 3 h, dispersed in an aqueous ammonium molybdate solution with 5 wt% ammonium molybdate content, and stirred at 25 °C for 24 h. The solid was filtered out and calcined in a calcination furnace at 550 °C for 2 h to obtain the modified supported catalyst;
[0033] (3) Alkylation reaction: 75 kg of the modified supported catalyst was mixed evenly with 2350 kg of aniline in a synthesis kettle. After reacting at 150 °C for 1 h, the temperature was raised to 310 °C, the pressure was adjusted to 4.8 MPa, and 1800 kg of ethylene was introduced and reacted for 11 h. After the reaction ended, heating was stopped and the temperature was lowered to 120 °C;
[0034] (4) After filtering the materials in the synthesis kettle, the liquid was transferred to an evaporation kettle, and then the ethylene in the synthesis kettle and the evaporation kettle was recovered. The vacuum pump was turned on to a vacuum degree of -0.099 MPa, and the temperature was raised to 140 °C to distill out the crude products of 2,6 - diethylaniline and o - ethylaniline;
[0035] (5) Rectification: The vacuum pump was turned on to a vacuum degree of -0.099 MPa to separate and refine the crude products of 2,6 - diethylaniline and o - ethylaniline.
[0036] Example 3
[0037] (1) Preparation of modified supported catalyst: Tetraethyl orthosilicate, aluminum isopropoxide and isopropanol were dissolved in cyclohexane 12 times the mass of tetraethyl orthosilicate at a mass ratio of 1:0.07:0.3 to form solution A. Bis(2-hydroxyethyl)methyltetradecylammonium chloride 0.49 times the mass of tetraethyl orthosilicate and tetramethylammonium fluoride 0.22 times the mass of tetraethyl orthosilicate were dissolved in deionized water 10 times the mass of tetraethyl orthosilicate to form solution B. Solution A was added to solution B at a rate of 5 mL / min and stirred at 200 rpm for 40 min at room temperature, then transferred to a reaction kettle and reacted at 120 °C for 8 h. The solid was filtered out, washed 3 times with deionized water and ethanol, dried in an oven at 60 °C for 24 h, and calcined in a calcination furnace at 600 °C for 8 h to obtain the modified catalyst;
[0038] (2) The modified catalyst was dispersed in a 0.4 mol / L aqueous sodium hydroxide solution and stirred at 120 rpm at 85 °C for 2 h, then immediately cooled with an ice-water bath and repeated 3 times. Then it was stirred at 85 °C and 100 rpm in a 2 mol / L aqueous ammonium chloride solution for 60 min and repeated 3 times, calcined in a calcination furnace at 600 °C for 4 h, dispersed in an aqueous ammonium molybdate solution with a molybdenum ammonium content of 5 wt%, stirred at 30 °C for 24 h, the solid was filtered out, and calcined in a calcination furnace at 600 °C for 3 h to obtain the modified supported catalyst;
[0039] (3) Alkylation reaction: 100 kg of the modified supported catalyst was mixed evenly with 2500 kg of aniline in a synthesis kettle. After reacting at 160 °C for 1 h, the temperature was raised to 310 °C, the pressure was adjusted to 5.0 MPa, and 2300 kg of ethylene was introduced and reacted for 14 h. After the reaction, heating was stopped and the temperature was lowered to 120 °C;
[0040] (4) After filtering the materials in the synthesis kettle, the liquid was transferred to an evaporation kettle, and then ethylene in the synthesis kettle and the evaporation kettle was recovered. The vacuum pump was turned on to a vacuum degree of -0.098 MPa and the temperature was raised to 140 °C to distill out the crude products of 2,6 - diethylaniline and o - ethylaniline;
[0041] (5) Rectification: The vacuum pump was turned on to a vacuum degree of -0.098 MPa to separate and refine the crude products of 2,6 - diethylaniline and o - ethylaniline.
[0042] Comparative Example 1
[0043] The difference between Comparative Example 1 and Example 2 lies in the difference in step (1). Step (1) is changed to: Dissolve tetraethyl orthosilicate, aluminum isopropoxide, and isopropanol in cyclohexane with a mass ratio of 1:0.07:0.25 and a volume 10 times that of tetraethyl orthosilicate to form Solution A. Dissolve tetraethylammonium fluoride with a mass 0.18 times that of tetraethyl orthosilicate in deionized water with a volume 8 times that of tetraethyl orthosilicate to form Solution B. Add Solution A to Solution B at a rate of 5 mL / min, stir at 200 rpm at room temperature for 35 min, then transfer it into a reaction kettle, react at 120°C for 6 h, filter to obtain the solid, wash it 3 times with deionized water and ethanol, dry it in an oven at 55°C for 19 h, and calcine it in a calcination furnace at 550°C for 6 h to obtain the modified catalyst. The remaining steps are the same as those in Example 2.
[0044] Comparative Example 2
[0045] The difference between Comparative Example 2 and Example 2 lies in the difference in step (1). Step (1) is changed to: Dissolve tetraethyl orthosilicate, aluminum isopropoxide, and isopropanol in cyclohexane with a mass ratio of 1:0.07:0.25 and a volume 10 times that of tetraethyl orthosilicate to form Solution A. Dissolve bis(2-hydroxyethyl)methyltetradecylammonium chloride with a mass 0.43 times that of tetraethyl orthosilicate in deionized water with a volume 8 times that of tetraethyl orthosilicate to form Solution B. Add Solution A to Solution B at a rate of 5 mL / min, stir at 200 rpm at room temperature for 35 min, then transfer it into a reaction kettle, react at 120°C for 6 h, filter to obtain the solid, wash it 3 times with deionized water and ethanol, dry it in an oven at 55°C for 19 h, and calcine it in a calcination furnace at 550°C for 6 h to obtain the modified catalyst. The remaining steps are the same as those in Example 2.
[0046] Comparative Example 3
[0047] The difference between Comparative Example 3 and Example 2 lies in the difference in step (1). Step (1) is changed to: Dissolve tetraethyl orthosilicate and isopropanol in cyclohexane with a mass ratio of 1:0.25 and a volume 10 times that of tetraethyl orthosilicate to form Solution A. Dissolve bis(2-hydroxyethyl)methyltetradecylammonium chloride with a mass 0.43 times that of tetraethyl orthosilicate and tetraethylammonium fluoride with a mass 0.18 times that of tetraethyl orthosilicate in deionized water with a volume 8 times that of tetraethyl orthosilicate to form Solution B. Add Solution A to Solution B at a rate of 5 mL / min, stir at 200 rpm at room temperature for 35 min, then transfer it into a reaction kettle, react at 120°C for 6 h, filter to obtain the solid, wash it 3 times with deionized water and ethanol, dry it in an oven at 55°C for 19 h, and calcine it in a calcination furnace at 550°C for 6 h to obtain the modified catalyst. The remaining steps are the same as those in Example 2.
[0048] Comparative Example 4
[0049] The difference between Comparative Example 4 and Example 2 lies in step (2), which is changed to: disperse the modified catalyst in an aqueous sodium hydroxide solution of 0.4 mol / L, stir at 120 rpm at 80 °C for 1.5 h, immediately cool with an ice-water bath, repeat 3 times, then stir in an aqueous ammonium chloride solution of 2 mol / L at 80 °C and 100 rpm for 45 min, repeat 3 times, and calcine in a calcination furnace at 550 °C for 3 h to obtain the modified supported catalyst. The remaining steps are the same as those in Example 2.
[0050] Effect Example
[0051] The performance analysis results of the production of coproduct OEA by DEA using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention are given in Table 1 below.
[0052] Table 1
[0053]
[0054]
[0055] From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4, it can be found that the modified supported catalyst uses bis(2-hydroxyethyl)methyltetradecylammonium chloride and tetramethylammonium fluoride as structure-directing agents, so that the lamellar structure of the catalyst is supported by long-chain organic substances between the layers, forming a stacked and ordered mesoscopic structure, achieving a swelling effect, increasing the contact area between the reactants and the active sites, improving the reaction efficiency, cooperating with the weak acid sites of tetramethylammonium fluoride, promoting the reaction while avoiding side reactions caused by strong acid sites, and improving the selectivity and yield of the target product; then adding aluminum isopropoxide to modify the molecular sieve framework to form hierarchical pores inside the particles, obtaining a layered porous molecular sieve with a high specific surface area and a large pore volume, enhancing the catalytic effect while providing a growth environment for subsequent loading; and then using ammonium molybdate for loading to form a hierarchical pore structure, providing a more unobstructed diffusion channel for the reactants and products, and improving the catalytic reaction efficiency.
[0056] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.
Claims
1. A method for producing DEA and co-producing OEA, characterized in that: The following steps are involved: (1) Preparation of modified supported catalyst: tetraethyl orthosilicate, aluminum isopropoxide and isopropanol are dissolved in cyclohexane to form solution A, di(2-hydroxyethyl)methyltetradecyl chloride quaternary ammonium salt and tetramethylammonium fluoride are dissolved in deionized water to form solution B, solution A is added to solution B, stirred at 200 rpm for 30 to 40 min at room temperature, then transferred into a reactor, reacted at 120° C. for 4 to 8 h, filtered to obtain a solid, washed with deionized water and ethanol three times, dried in an oven at 50 to 60° C. for 14 to 24 h, and calcined in a calcining furnace for 4 to 8 h to obtain a modified catalyst; (2) After the modified catalyst is etched with an alkaline solution, it is dispersed in an aqueous solution of ammonium molybdate, stirred at 20 to 30° C. for 24 hours, the solid is filtered out, and calcined in a calcining furnace for 1 to 3 hours to obtain a modified supported catalyst; (3) Alkylation reaction: 50-100 kg of modified supported catalyst and 2200-2500 kg of aniline were mixed evenly in a synthesis reactor, reacted at 140-160 ° C for 1 hour, then heated to 310 ° C, adjusted the pressure to 4.6-5.0 MPa, introduced 1300-2300 kg of ethylene, reacted for 8-14 hours, and after the reaction was completed, stopped heating and the temperature was lowered to 120 ° C; (4) After filtering the material in the synthesis kettle, the liquid is transferred to an evaporator, and then ethylene in the synthesis kettle and the evaporator is recovered, the vacuum pump is turned on, and the temperature is raised to 140° C. to evaporate the crude products of 2,6-diethylaniline and o-ethylaniline; (5) Distillation: Turn on the vacuum pump to separate and purify the crude products of 2,6-diethylaniline and o-ethylaniline.
2. The method for producing DEA and co-producing OEA according to claim 1, characterized in that: The mass ratio of tetraethyl orthosilicate, aluminum isopropoxide and isopropanol in step (1) is 1: (0.06-0.07): (0.2-0.3).
3. The method for producing DEA and co-producing OEA according to claim 1, characterized in that: The mass of cyclohexane in step (1) is 8 to 12 times the mass of tetraethyl orthosilicate.
4. The method for producing DEA and co-producing OEA according to claim 1, characterized in that: The mass ratio of di(2-hydroxyethyl)methyltetradecyl chloride quaternary ammonium salt, tetramethylammonium fluoride and tetraethyl orthosilicate in step (1) is 1:(0.37-0.49):(0.14-0.22).
5. The method for producing DEA and co-producing OEA according to claim 1, characterized in that: The mass of deionized water in step (1) is 7 to 10 times the mass of tetraethyl orthosilicate.
6. The method for producing DEA and co-producing OEA according to claim 1, characterized in that: The rate at which solution A is added to solution B in step (1) is 5 mL / min.
7. The method for producing DEA and co-producing OEA according to claim 1, characterized in that: The alkaline solution etching step in step (2) is as follows: the modified catalyst is dispersed in a 0.4 mol / L sodium hydroxide aqueous solution, stirred at 75-85°C and 120 rpm for 1-2 hours, immediately cooled in an ice water bath, repeated 3 times, then stirred at 75-85°C and 100 rpm for 30-60 minutes in a 2 mol / L ammonium chloride aqueous solution, repeated 3 times, and then placed in a calcination furnace for calcination for 2-4 hours.
8. The method for producing DEA and co-producing OEA according to claim 1, characterized in that: The content of ammonium molybdate in the ammonium molybdate aqueous solution in step (2) is 5wt%.
9. The method for producing DEA and co-producing OEA according to claims 1 to 8, characterized in that: The temperature of the calcining furnace is 500-600°C.
10. The method for producing DEA and co-producing OEA according to claims 1 to 9, characterized in that: After the vacuum pump is turned on, the vacuum degree is -0.1 to -0.098 MPa.