An amine etherification reaction method and the reactor used therefor

Abstract

The present invention belongs to the chemical engineering field and relates to a new amine etherification reactor and a corresponding amine etherification reaction method. The present invention discloses an amine etherification reactor, which includes an alkanolamine storage tank, a concentrated sulfuric acid storage tank, a Venturi-type distributor, a reaction kettle, a water collection tank with an exhaust port, etc.; The present invention is a new method for obtaining amine ethers by using alkanolamine, concentrated sulfuric acid and alkali (sodium hydroxide) as main raw materials, through steps such as continuous heat-collecting mixing and batching, water-controlled etherification, neutralization, solid-liquid separation and rectification separation. The water fraction separated by atmospheric rectification can be recycled, and the use of organic solvents is not involved. Therefore, the safety risks caused by the use of organic solvents are reduced, the inherent safety of the process is improved, the reaction time is shortened and the work efficiency is increased.

Description

Technical Field

[0001] The present invention belongs to the chemical industry field, and relates to a new amine etherification reactor and a corresponding amine etherification reaction method, which are particularly suitable for the etherification production of bis(dimethylaminoethyl) ether (hereinafter referred to as BDMAEE) from N,N-dimethylethanolamine (hereinafter referred to as DMEA), the etherification production of bis(morpholinylethyl) ether (hereinafter referred to as DMDEE) from triethanolamine (hereinafter referred to as TEOA), the etherification production of bis(methylaminoethyl) ether (hereinafter referred to as BMAEE) from methylethanolamine (hereinafter referred to as MMEA), the etherification production of N-methylmorpholine (hereinafter referred to as NMM) from N-methyldiethanolamine (hereinafter referred to as MDEA), etc. Background Art

[0002] There are many synthesis methods for important amine catalysts such as BDMAEE and DMDEE in the polyurethane industry. Taking BDMAEE as an example, the following description is given, and DMDEE, BMAEE, and NMM also have similar methods.

[0003] BDMAEE is a colorless liquid and soluble in water. Its structural formula is as shown in S-1. It is one of the important amine catalysts in the polyurethane industry, having extremely high catalytic activity and selectivity for the foaming reaction; it is applicable to the foaming catalysts of all flexible foams. Its strong catalytic effect in the foaming reaction can be balanced by a strong gel catalyst. In the application of flexible slab foam formulations, BDMAEE can improve the processing of foams from low to high density grades and can be filled to high resilience grades. Due to its unique functional characteristics, BDMAEE is also an efficient catalyst for high resilience molded foams.

[0004]

[0005] There are already various synthesis methods for BDMAEE, which are specifically as follows:

[0006] 1) Patent US4177212A discloses a preparation method of BDMAEE. This process discloses a one-pot reaction, using DMEA and the sodium salt of DMEA as raw materials, adding chlorosulfonic acid, thionyl chloride, and sulfonyl chloride as chlorinating reagents for reaction, and using long-chain alkanes as solvents, with a yield of 54%. The main disadvantages of this method are: the post-treatment of chlorine-containing compounds is complex, there are many by-products, and the corrosion of equipment is serious.

[0007] The reaction equation is as follows:

[0008]

[0009] 2) Patent US6150559A discloses a preparation method of BDMAEE. This process uses DMEA as the raw material and a solid base zeolite catalyst for continuous reaction. At a reaction temperature of 400 °C, the yield is 25%. The main disadvantages of this method are: high reaction temperature, many side reactions, poor selectivity, and low yield.

[0010] The reaction equation is as follows:

[0011]

[0012] 3) Patent US4247482A discloses a preparation method of BDMAEE. This process uses the sodium salt of DMEA and DMEA under the action of sulfur trioxide to react at 115 °C for 2.5 h to obtain BDMAEE, and the yield is 63% - 68%. Sulfur trioxide is highly reactive and has a high operation safety risk. It is a serious pollutant and is not environmentally friendly.

[0013] The reaction equation is as follows:

[0014]

[0015] 4) Patent CN105837457A discloses a preparation method of BDMAEE. This method first prepares a metal oxide, and then prepares a metal catalyst through the metal oxide. Using the catalytic action of the metal catalyst, BDMAEE is prepared with dimethylamine and dimethylaminoethoxyethanol as raw materials. Dimethylamine is not environmentally friendly, and there is a problem of less supply in the industrial raw material market for the main raw material dimethylaminoethoxyethanol, which is not conducive to industrial production.

[0016] The reaction equation is as follows:

[0017]

[0018] 5) Patent CN103450035A discloses a preparation method of BDMAEE. This process uses dimethylaminoethoxyethanol and synthesizes BDMAEE through two steps of ammonolysis and condensation reduction. The first step requires reaction at a pressure of 10 MPa and a high temperature of 180 °C, and the second step requires Pd / C as the catalyst, a pressure of 2.5 MPa, and a reaction temperature of 100 °C. There is a problem of less supply in the industrial raw material market for the main raw material dimethylaminoethoxyethanol. Both steps require reaction under high temperature and high pressure, which requires high equipment requirements and relatively harsh process conditions, and is not conducive to industrialization.

[0019] The reaction equation is as follows:

[0020]

[0021] 6) Patent CN106316868A discloses a preparation method of BDMAEE. This process uses dimethylamine and ethylene oxide to react to obtain 2-(2-(dimethylamino)ethoxy)ethanol. Then, dimethylamine and the synthesized 2-(2-(dimethylamino)ethoxy)ethanol react under the action of the catalyst Cu-Ni / γ-Al2O3 at a temperature controlled at 190-220 °C and a reaction pressure of 10-25 MPa for 6-13 h to obtain BDMAEE. This method requires high-temperature and high-pressure reactions, has high requirements for equipment, ethylene oxide has high activity, there are relatively high safety risks during the production process, and dimethylamine is not environmentally friendly.

[0022] The reaction equation is as follows:

[0023]

[0024] 7) Patent CN110028413A discloses a preparation method of BDMAEE. This process uses DMEA as a raw material and prepares BDMAEE by the sulfuric acid dehydration method. Under the action of a catalyst, after an etherification reaction at 150-190 °C for 5-15 h, an organic solvent is added and then neutralization and rectification are carried out in sequence to obtain the product, and the yield is 65%. When chemically mixing in this process, a large amount of circulating water needs to be introduced to maintain a certain dropping temperature, resulting in a large waste of energy, an extended reaction time, an extended entire production cycle, and restricting the expansion of production capacity. The organic solvent used during extraction belongs to Class A liquids and has high safety risks. A catalyst with a cumbersome production process is used, the raw material cost is high, the yield is low, and it is not environmentally friendly.

[0025] The reaction equation is as follows:

[0026]

[0027] The synthesis methods in the existing literature have high raw material consumption, reduced yields, and there are poisoning and safety hazards. Therefore, improving the synthesis process of BDMAEE is of great significance for reducing raw material consumption, increasing the product yield and quality, reducing the reaction time, and improving production efficiency. Summary of the Invention

[0028] The technical problem to be solved by the present invention is to provide a synthesis method of amine ether and the amine etherification reactor used.

[0029] To solve the above technical problem, the present invention provides an amine etherification reactor, including an alkanolamine storage tank, a concentrated sulfuric acid storage tank, a Venturi-type distributor, a reaction kettle, and a water collection tank with an exhaust port;

[0030] The concentrated sulfuric acid storage tank is connected to the Venturi-type distributor through a concentrated sulfuric acid metering pump, and the alkanolamine storage tank is connected to the Venturi-type distributor through an alkanolamine metering pump;

[0031] The top of the reactor is respectively provided with a material inlet, a water inlet, and an alkali inlet; the outlet of the Venturi distributor is directly opposite to the material inlet of the reactor;

[0032] The bottom outlet of the reactor is divided into two paths. One path is successively connected to the Venturi distributor through a reaction liquid circulation valve and a reaction liquid forced circulation pump; the other path is connected to a discharging valve;

[0033] An air lift pipe is provided at the top of the reactor, and the air lift pipe is connected to a water collection tank through a condenser;

[0034] The inert gas insertion pipe is connected to the inner cavity of the reactor.

[0035] As an improvement to the amine etherification reactor of the present invention: a reactor jacket is provided on the outer surface of the reactor, and a coil pipe with a hot oil inlet and a hot oil outlet is provided in the reactor jacket, and the reactor is heated by using the reactor jacket.

[0036] As a further improvement to the amine etherification reactor of the present invention: a thermometer is provided in the reactor; a water outlet valve is provided at the bottom of the water collection tank.

[0037] As a further improvement to the amine etherification reactor of the present invention: the Venturi distributor includes an inner shell and an outer shell;

[0038] The inner shell is sleeved inside the outer shell, and the top surface of the inner shell is higher than the top surface of the outer shell; the side wall of the inner shell is hermetically connected to the top surface of the outer shell;

[0039] The top surface of the inner shell is provided with an inner shell inlet, and the outlet of the reaction liquid forced circulation pump is hermetically connected to the inner shell inlet through a connecting pipe I, and the bottom of the inner shell is open; the open end is located in the inner cavity of the outer shell;

[0040] On the side wall of the outer shell, there are respectively provided an outer shell inlet I and an outer shell inlet II; the outlet of the alkanolamine metering pump is hermetically connected to the outer shell inlet I through a connecting pipe II, and the outlet of the concentrated sulfuric acid metering pump is hermetically connected to the outer shell inlet II through a connecting pipe III;

[0041] The outer shell inlet I and the outer shell inlet II are at the same height and are both above the open bottom of the inner shell; therefore, the materials are mixed in the inner cavity of the outer shell below the open bottom of the inner shell;

[0042] The bottom surface of the outer shell is provided with a material outlet, one end of a connecting pipe IV is hermetically connected to the material outlet, and the other end is hermetically connected to the material inlet of the reactor.

[0043] As a further improvement to the amine etherification reactor of the present invention: the inner shell is an inverted conical cylinder;

[0044] The outer shell body is composed of a large cylinder, an inverted cone cylinder, a small cylinder, and a cone cylinder which are integrated and arranged in sequence from top to bottom;

[0045] The inner diameter of the large cylinder = the inner diameter of the top of the inverted cone cylinder, and the inner diameter of the bottom of the inverted cone cylinder = the inner diameter of the small cylinder = the inner diameter of the top of the cone cylinder;

[0046] An outer shell body feed port 1 and an outer shell body feed port 2 are arranged on the side wall of the inverted cone cylinder;

[0047] The open position at the bottom of the inner shell body corresponds to the height position of the inverted cone cylinder.

[0048] The present invention also simultaneously provides an amine etherification reaction method. Using the above amine etherification reactor, with alkanolamine, concentrated sulfuric acid, and an alkali (sodium hydroxide) as reaction raw materials and water as a solvent, it includes the following steps:

[0049] 1), Continuous heat-collecting mixing and batching:

[0050] Open the reaction liquid circulation valve of the reaction kettle pre-filled with etherification liquid (reaction liquid), start the reaction liquid forced circulation pump, and the etherification liquid returns to the reaction kettle after passing through the Venturi-type distributor, and the etherification liquid is forced to circulate;

[0051] Add alkanolamine to the alkanolamine storage tank, add concentrated sulfuric acid to the concentrated sulfuric acid storage tank, and while opening the reaction liquid circulation valve, open the alkanolamine metering pump and the concentrated sulfuric acid metering pump, and feed into the reaction kettle through the Venturi-type distributor. The molar ratio of sulfuric acid to alkanolamine is 1.0 - 2.0:1 (preferably 1.19 - 1.8:1), and the flow rates Q 反应液 、Q 醇胺 、Q 浓硫酸 are controlled according to the set ratio; the metered alkanolamine and concentrated sulfuric acid are continuously fed into the reaction kettle. While continuously feeding, under the action of the Venturi-type distributor, the reaction neutralization heat of the alkanolamine and concentrated sulfuric acid is used for flash evaporation in the reaction kettle (under the condition of not passing cooling water and only relying on the system mixing heat generation and spontaneous heat dissipation, keeping the temperature in the kettle not lower than a certain temperature), and the moisture content of the reaction system in the reaction kettle is controlled to be 0.03 - 0.9 Wt% by introducing an inert gas;

[0052] The water and gas generated by the reaction enter the condenser through the air lift pipe, the generated water after condensation is collected and metered by the water collection tank, and the exhaust gas is exhausted through the exhaust port; after the feeding of the alkanolamine and concentrated sulfuric acid is completed, stop the alkanolamine metering pump and the concentrated sulfuric acid metering pump;

[0053] Note: The etherification liquid is the product obtained in step 2); during the first reaction, since there is no etherification liquid, first open the alkanolamine metering pump and the concentrated sulfuric acid metering pump to feed into the reaction kettle through the Venturi-type distributor. When the volume of the reaction liquid in the reaction kettle exceeds 10 ml, the reaction liquid forced circulation pump can be normally started and run, and at this time, the reaction liquid forced circulation pump can be opened;

[0054] Flow rate Q 反应液 represents the flow rate of the materials in the reactor; Q 醇胺 represents the flow rate of the alkanolamine flowing out of the alkanolamine storage tank, Q 浓硫酸 represents the flow rate of the concentrated sulfuric acid flowing out of the concentrated sulfuric acid storage tank;

[0055] In this step, by controlling the flow rate, it can ensure that the alkanolamine and the concentrated sulfuric acid are fed simultaneously, and the feeding time is about 1 - 1.5 h; under the action of an inert gas (such as nitrogen), the moisture in the reaction system in the reactor is controlled;

[0056] 2), Water - controlled etherification reaction:

[0057] After the feeding in step 1) is completed, open the hot oil outlet and the hot oil inlet of the reactor jacket to continue heating the reaction system, control the reaction temperature to be 150 - 220 °C (at the temperature shown by the thermometer, preferably 180 - 210 °C), and continue to control the moisture content in the reaction system in the reactor to be 0.03 - 0.9 Wt%. When the total amount of water distilled into the water collection tank reaches 50 - 100% of the theoretical amount of water produced by etherification (by weight), stop the reaction to obtain the etherification liquid;

[0058] Note: The total amount of water is the total amount of water produced in step 1) and step 2);

[0059] 3), Neutralization:

[0060] First, release a pre - added amount of the etherification liquid from the discharge valve of the etherification liquid obtained in step 2). After the discharge is completed, close the discharge valve, then add water from the water inlet for dilution, and then add solid base (such as sodium hydroxide) from the base inlet for neutralization to make the pH value of the system reach 9 - 10 to obtain a solid - liquid mixture;

[0061] 4), Solid - liquid separation:

[0062] After discharging the solid - liquid mixture obtained in step 3) from the discharge valve, filter it to obtain the filtrate;

[0063] 5), Rectification:

[0064] Rectify the filtrate obtained in step 4). First, rectify (at atmospheric pressure) to separate and obtain the water fraction (which can be recycled), and then rectify and separate to obtain the amine - ether fraction.

[0065] Note: During the rectification process, recoverable alkanolamine fractions (which can be recycled), intermediate fractions, and amine - ether fractions are obtained.

[0066] As an improvement to the amine - etherification reaction method of the present invention:

[0067] In the said step 1):

[0068] The weight of the etherification liquid pre-loaded into the reactor (11) is 0 to 20 Wt% (preferably 1 to 20 Wt%) of the sum of the weights of the alkanolamine and concentrated sulfuric acid as raw materials;

[0069] The flow rate (volume flow rate) is controlled to be Q 反应液 : Q 醇胺 : Q 浓硫酸 = 1:0.04 to 3:0.04 to 3.

[0070] Preferably, Q 反应液 : Q 醇胺 : Q 浓硫酸 = 1:0.18 to 0.32:0.15 to 0.21.

[0071] As a further improvement of the amine etherification reaction method of the present invention:

[0072] When the total amount of water distilled into the water collection tank reaches 90 to 95% of the theoretical water output (weight) of the etherification, the reaction is stopped.

[0073] As a further improvement of the amine etherification reaction method of the present invention:

[0074] The weight of the etherification liquid pre-loaded into the reactor (11) is 3 to 10 Wt% of the sum of the weights of the alkanolamine and concentrated sulfuric acid as raw materials.

[0075] As a further improvement of the amine etherification reaction method of the present invention:

[0076] The alkanolamine and concentrated sulfuric acid are mixed under the action of a Venturi-type distributor; flash evaporation is carried out using the heat of neutralization of the alkanolamine and concentrated sulfuric acid under the action of the Venturi-type distributor;

[0077] Drainage is carried out through the water outlet valve.

[0078] The reaction equation of BDMAEE of the present invention is as follows in Formula S-2:

[0079]

[0080]

[0081] The reaction equation of DMDEE of the present invention is as follows in Formula S-3:

[0082]

[0083] The reaction equation of BMAEE of the present invention is as follows in Formula S-4:

[0084]

[0085] The reaction equation of NMM of the present invention is as follows in Formula S-5:

[0086]

[0087] The present invention relates to a new method for obtaining amine ethers by using alkanolamine, concentrated sulfuric acid and alkali (sodium hydroxide) as main raw materials, through steps such as continuous heat-collecting mixing and batching, water-control etherification, neutralization, solid-liquid separation and rectification separation. The water fraction separated by atmospheric rectification can be recycled, without involving the use of organic solvents. Therefore, the safety risks caused by the use of organic solvents are reduced, the inherent safety of the process is improved, the reaction time is shortened and the work efficiency is increased. The alkanolamine separated by vacuum rectification is recycled to the water-control etherification reaction, improving the atom economy of the process, reducing material consumption and costs from the source of the process, and reducing the emission of three wastes. In addition, the multifunctional etherification reaction device developed by the present invention has the following four advantages: one is that it can continuously mix raw materials, the second is that it can utilize the neutralization heat of the raw material reaction, the third is that it can utilize the neutralization heat for flash evaporation, and the fourth is that it can achieve water-control etherification. It can effectively increase the reaction rate, reduce energy consumption, improve the product yield and production efficiency, and has a low total production cost and simple operation. Description of the Drawings

[0088] The following further elaborates on the specific embodiments of the present invention with reference to the accompanying drawings.

[0089] Figure 1 is a schematic diagram of the etherification reaction device of the present invention;

[0090] Figure 2 is Figure 1 a detailed view of the Venturi-type distributor 5 in Specific Embodiments

[0091] The following further describes the present invention with reference to specific embodiments, but the protection scope of the present invention is not limited thereto:

[0092] Device Example 1. A device for producing amine ethers, as Figure 1 shown:

[0093] It includes an alkanolamine storage tank 1, an alkanolamine metering pump 2, a concentrated sulfuric acid storage tank 3, a concentrated sulfuric acid metering pump 4, a Venturi-type distributor 5 (material: zirconium), a reaction liquid forced circulation pump 6, a reaction liquid circulation valve 7, a discharge valve 8, a hot oil inlet 9, a hot oil outlet 10, a reaction kettle 11, a reaction kettle jacket 12, a water feed inlet 13, an alkali feed inlet 14, a thermometer 15, an inert gas insertion tube 16, an air lift tube 17, a condenser 18, an exhaust port 19, a water collection tank 20, and a water outlet valve 21.

[0094] The concentrated sulfuric acid storage tank 3 is connected to the Venturi-type distributor 5 through the concentrated sulfuric acid metering pump 4, and the alkanolamine storage tank 1 is connected to the Venturi-type distributor 5 through the alkanolamine metering pump 2.

[0095] The outer surface of the reactor 11 is provided with a reactor jacket 12. A coil pipe with a hot oil inlet 9 and a hot oil outlet 10 is arranged inside the reactor jacket 12, and the reactor 11 is heated by the reactor jacket 12. The top of the reactor 11 is respectively provided with a material feed inlet, a water feed inlet 13, an alkali feed inlet 14 and an air lift pipe 17. A thermometer 15 and an inert gas insertion pipe 16 are also arranged inside the reactor 11.

[0096] The Venturi type distributor 5 is located above the reactor 11; the discharge port of the Venturi type distributor 5 is directly opposite to the material feed inlet of the reactor 11;

[0097] The bottom discharge port of the reactor 11 is divided into two paths. One path is successively connected to the Venturi type distributor 5 through a reaction liquid circulation valve 7 and a reaction liquid forced circulation pump 6; the other path is connected to a discharging valve 8.

[0098] The air lift pipe 17 is connected to a water collection tank 20 through a condenser 18. An exhaust port 19 is arranged at the top of the water collection tank 20, and a water outlet valve 21 is arranged at the bottom of the water collection tank 20.

[0099] The structure of the Venturi type distributor 5 is specifically as Figure 2 shown: The Venturi type distributor 5 includes an inner housing 51 and an outer housing 52; the inner housing 51 is sleeved inside the outer housing 52, and the top surface of the inner housing 51 is higher than the top surface of the outer housing 52; the top surface of the outer housing 52 is hermetically connected to the side wall of the inner housing 51;

[0100] The top surface of the inner housing 51 is provided with an inner housing feed inlet. The outlet of the reaction liquid forced circulation pump 6 is hermetically connected to the inner housing feed inlet through a connecting pipe I 53. The bottom of the inner housing 51 is open (fully open); the open part is located in the inner cavity of the outer housing 52;

[0101] On the side wall of the outer housing 52, there are respectively provided an outer housing feed inlet one and an outer housing feed inlet two; the outlet of the alkanolamine metering pump 2 is hermetically connected to the outer housing feed inlet one through a connecting pipe II 54, and the outlet of the concentrated sulfuric acid metering pump 4 is hermetically connected to the outer housing feed inlet two through a connecting pipe III 55;

[0102] The outer housing feed inlet one and the outer housing feed inlet two are at the same height and are both above the bottom open part of the inner housing 51; therefore, the materials are mixed in the inner cavity of the outer housing 52 below the bottom open part of the inner housing 51;

[0103] The bottom surface of the outer housing 52 is provided with a material outlet. One end of a connecting pipe IV 56 is hermetically connected to the material outlet of the outer housing 52, and the other end is hermetically connected to the material feed inlet of the reactor 11.

[0104] The inner housing 51 is an inverted conical cylinder; the inner housing 51 has a top surface and the bottom surface is fully open.

[0105] The outer housing 52 is composed of a large cylinder 521, an inverted cone 522, a small cylinder 523, and a cone 524 that are integrated and arranged in sequence from top to bottom. That is, the inner diameter of the large cylinder 521 = the inner diameter of the top of the inverted cone 522, the inner diameter of the bottom of the inverted cone 522 = the inner diameter of the small cylinder 523 = the inner diameter of the top of the cone 524; the top surface of the large cylinder 521 forms the top surface of the outer housing 52, and the bottom surface of the cone 524 forms the bottom surface of the outer housing 52.

[0106] An outer housing feed port one and an outer housing feed port two are provided on the side wall of the inverted cone 522.

[0107] The open position at the bottom of the inner housing 51 corresponds to the height position of the inverted cone 522.

[0108] The specific dimensions can be as follows:

[0109] The inner radius of the top surface of the inner housing 51 is 15 mm; the diameter of the open bottom is 10 mm; the total length of the side wall of the inner housing 51 is 60 mm.

[0110] The top surface of the large cylinder 521 of the outer housing 52 is flush with the 10 mm position of the side wall length of the inner housing 51; the top surface of the large cylinder 521 is annular, and the width of the annulus is 10 mm; the height of the large cylinder 521 is 10 mm.

[0111] The side wall length of the inverted cone 522 is 60 mm, and an outer housing feed port one and an outer housing feed port two are respectively provided at the middle of the side wall length of the inverted cone 522;

[0112] The inner diameter (diameter) of the bottom of the inverted cone 522 is 15 mm;

[0113] The height of the small cylinder 523 is 10 mm;

[0114] The inner bottom diameter of the cone 524 is 30 mm (i.e., the inner radius is 15 mm), and the side wall length of the cone 524 is 15 mm.

[0115] In the present invention:

[0116] The concentrated sulfuric acid is sulfuric acid with a mass concentration ≥ 98%.

[0117] The volume of the reaction kettle (11) is 2000 ml.

[0118] The volume flow rate can be, for example, ratioed based on the reaction liquid circulation amount of 20 ml / min.

[0119] After comparison with the standard sample, nuclear magnetic resonance hydrogen spectrum, and nuclear magnetic resonance carbon spectrum detection, the molecular structures of the products obtained in the following cases are all correct.

[0120] Example 1-1, A method for synthesizing BDMAEE, successively perform the following steps:

[0121] 1) Continuous heat - collecting type mixed batching:

[0122] Add 232.4 g (2.611 mol) of DMEA into the alkanolamine storage tank 1, and add 470 g (4.7 mol) of concentrated sulfuric acid into the concentrated sulfuric acid storage tank 3. At the same time, open the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4, and feed materials into the reaction kettle 11 through the Venturi - type distributor 5. The above - mentioned DMEA and concentrated sulfuric acid are both fed within about 1 hour at the same time.

[0123] After feeding for 2 min, open the reaction liquid circulation valve 7 of the reaction kettle 11, start the reaction liquid forced circulation pump 6 to force - circulate the reaction liquid in the reaction kettle 11, and mix the materials (DMEA, concentrated sulfuric acid, reaction liquid) through the Venturi - type distributor 5.

[0124] Note: Generally speaking, as long as the amount of the reaction liquid in the reaction kettle 11 exceeds about 10 ml, the reaction liquid forced circulation pump 6 can operate normally, and at this time, the reaction liquid forced circulation pump 6 can be started. After feeding for 2 min, the amount of the reaction liquid in the reaction kettle 11 is about 17 ml.

[0125] Control the feeding flow rate to be Q 反应液 : Q DMEA : Q 浓硫酸 = 1:0.22:0.21 (volume flow ratio), continuously feed the measured DMEA and concentrated sulfuric acid into the reaction kettle 11. While continuously feeding, under the action of the Venturi - type distributor 5, use the reaction heat of neutralization of DMEA and concentrated sulfuric acid for flash evaporation. Note: The flash evaporation is carried out in the reaction kettle 11. After the materials are mixed through the Venturi - type distributor 5, the temperature rises rapidly. Therefore, the water in the materials after passing through the Venturi - type distributor 5 becomes water vapor in the reaction kettle 11 to achieve flash evaporation.

[0126] Nitrogen enters the reaction system in the reaction kettle 11 through the inert gas insertion tube 16. Under the action of nitrogen, control the water content in the reaction system to be 0.3 - 0.35 Wt%. Note: Detect the water content in the reaction system in the reaction kettle 11 (water analysis) by the conventional volumetric method; when the water content exceeds the standard, increase the nitrogen flow rate. Nitrogen can drive the water generated in the reaction in the reaction kettle 11 to be discharged from the air - lift pipe 17.

[0127] Without passing cooling water and only relying on the heat generated by system mixing and spontaneous heat dissipation, the temperature inside the reaction kettle 11 can be maintained not lower than 150 °C. The water generated by the reaction and nitrogen enter the condenser 18 through the air - lift pipe 17. Use the water collection tank 20 to collect and measure the condensed generated water. Since nitrogen cannot be condensed, it is discharged through the exhaust port 19. The collected generated water can finally be drained through the water outlet valve 21.

[0128] The time for continuous heat - collecting mixing of ingredients is about 1 h.

[0129] 2), water - controlled etherification reaction:

[0130] After the feeding in step 1) is completed, only the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4 are stopped, the hot oil outlet 10 and the hot oil inlet 9 of the reaction kettle jacket 12 are opened, and the reaction system in the reaction kettle 11 is continuously heated. When the thermometer 15 shows a temperature of 200 - 210 °C, under the action of nitrogen in the inert gas insertion tube 16, the water content of the reaction system is controlled to be 0.3 - 0.35 Wt%. When the total amount of water distilled into the water collection tank 20 reaches 21.15 g (90% of the theoretical water output of etherification), stop heating (i.e., close the hot oil outlet 10 and the hot oil inlet 9), and close the reaction liquid forced - circulation pump 6 to obtain about 678.1 g of etherification liquid. The reaction takes 7 h, the reaction power consumption is about 9 KW, and the daily production capacity is 3.43 batches.

[0131] The theoretical water output of etherification = 232.4 / 89 / 2 * 18 = 23.5 g.

[0132] The total amount of water 21.15 g is the total amount of water generated in step 1) and step 2).

[0133] 3), neutralization:

[0134] First, 70.24 g of the etherification liquid obtained in step 2) is discharged from the discharge valve 8. After the discharging is completed, the discharge valve 8 is closed. Then, 315 g of water is added from the water inlet 13 for dilution. After the diluted liquid is discharged from the discharge valve 8, it is subjected to vacuum filtration outside the reaction kettle, and the obtained filtrate is returned to the reaction kettle 11 from the water inlet 13; the amount of solid coke is 3.7 g, and the carbon - deposition rate is 1.59 Wt% based on DMEA. About 338 g of solid sodium hydroxide is added from the alkali inlet 14 to neutralize the filtrate, so that the pH value of the system reaches 9 - 10 to obtain a crude solid - liquid mixture. The crude product is sampled for GC analysis, and the BDMAEE content is 80.23%.

[0135] Note: The purpose of vacuum filtration is to remove coke, etc.

[0136] 4), solid - liquid separation:

[0137] The crude solid - liquid mixture obtained in step 3) is discharged from the discharge valve 8 and then filtered to obtain a filtrate.

[0138] Note: The purpose of filtration is to remove sodium sulfate generated by neutralization.

[0139] 5), rectification:

[0140] The filtrate obtained in step 4) is subjected to rectification. First, water fraction is separated by rectification (under normal pressure), and the water fraction is recycled for the next round of neutralization and dilution. Rectification is continued under a pressure of 8 mmHg, and 33.5 g of DMEA fraction at 60 - 70 °C is recovered by condensation. This DMEA fraction is a DMEA fraction with a content of 99.4%; 18.5 g of transitional fraction above 70 - 110 °C is recovered by condensation. This transitional fraction is BDMAEE with a content of less than 99%; 128.9 g of BDMAEE fraction above 110 - 115 °C is recovered by condensation. The mass content of BDMAEE in this BDMAEE fraction is 99.94%, and the yield is 61.7%.

[0141] BDMAEE yield = BDMAEE fraction amount / BDMAEE theoretical production amount (calculated based on the DMEA feed amount).

[0142] Example 1 - 2. A method for synthesizing BDMAEE, which successively performs the following steps:

[0143] 1), Continuous heat - collecting type mixing and batching:

[0144] 70.24 g of the etherification liquid prepared in Example 1 - 1 is pre - loaded into the reaction kettle 11;

[0145] The reaction liquid circulation valve 7 of the reaction kettle 11 is opened, and the reaction liquid forced circulation pump 6 is started to perform forced circulation on the reaction liquid. At the same time, the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4 are also opened, and the materials are mixed through the Venturi - type distributor 5.

[0146] The rest is the same as step 1) of Example 1 - 1.

[0147] 2), Water - controlling etherification reaction:

[0148] The same as step 2) of Example 1 - 1. About 748.34 g of etherification liquid is obtained. The reaction time is 7 h, the reaction power consumption is about 9 KW, and the daily production capacity is 3.43 batches.

[0149] 3), Neutralization:

[0150] The amount of water for dilution added from the water feed port 13 is changed from 315 g to 350 g; the amount of sodium hydroxide for neutralization added from the alkali feed port 14 is changed from about 338 g to about 376 g; the rest is the same as step 3) of Example 1 - 1.

[0151] The amount of solid coke obtained is 4.7 g, and the carbon deposition rate is 2.02 Wt% based on DMEA. The BDMAEE content in the crude product sample analyzed by GC is 86.12%.

[0152] Steps 4) - step 5) are the same as steps 4) - step 5) of Example 1 - 1, and the obtained results are as follows:

[0153] Rectify the filtrate obtained in step 4). First, rectify (under normal pressure) to separate the water fraction, and the water fraction is recycled for the next round of neutralization and dilution. Continue rectifying under a pressure of 8 mmHg, condense and recover 27 g of the DMEA fraction at 60 - 70 °C, and this DMEA fraction is a DMEA fraction with a content of 99.5%; condense and recover 19.2 g of the transition fraction above 70 - 110 °C, and this transition fraction is BDMAEE with a content of less than 99%; condense and recover 158.8 g of the BDMAEE fraction above 110 - 115 °C, and the BDMAEE mass content in this BDMAEE fraction is 99.95% with a yield of 76.02%.

[0154] Examples 1 - 3: Use the DMEA fraction with a content of 99.5% obtained in Examples 1 - 2 to replace DMEA as the raw material, with the weight remaining unchanged; use the water fraction obtained in Examples 1 - 2 to replace the water for dilution, with the weight remaining unchanged; the rest is the same as Examples 1 - 2. The results obtained are as follows:

[0155] The amount of solid coke obtained is 4.6 g, the carbon deposition rate is 1.98 Wt%, the BDMAEE content obtained by GC analysis of the crude product sample is 86.07%, 157.9 g of the BDMAEE fraction is obtained, the BDMAEE mass content in this BDMAEE fraction is 99.47%, and the yield is 75.59%. The reaction time is 7 h, the reaction power consumption is about 9 KW, and the daily production capacity is 3.43 batches.

[0156] Example 1 - 4: Compared with Examples 1 - 2: The amount of DMEA used remains unchanged, and the amount of concentrated sulfuric acid used is changed to 3.9165 mol, that is, the sulfuric acid:DMEA molar ratio is changed to 1.5:1, and the corresponding feed flow rate is controlled as Q 反应液 :Q DMEA :Q 浓硫酸 = 1:0.22:0.18 (volume flow rate ratio); the rest is basically the same as Examples 1 - 2.

[0157] The results obtained are as follows:

[0158] The amount of solid coke obtained is 14.1 g, the carbon deposition rate is 6.07 Wt%, the BDMAEE content obtained by GC analysis of the crude product sample is 43.4%, 76.4 g of the BDMAEE fraction is obtained, the BDMAEE mass content in this BDMAEE fraction is 99.51%, and the yield is 36.57%. The reaction time is 16 h, the reaction power consumption is about 17 KW, and the daily production capacity is 1.5 batches. Compared with Examples 1 - 2, the reaction time is extended by 9 h, the time extension rate is 128.6%, the energy consumption increases by 8 KW, the increase rate is 88.89%, the daily production capacity decreases by 1.93 batches, and the production capacity reduction rate is 56.27%.

[0159] Comparative Example 1-1: Replace the "Venturi-type distributor" in Example 1-2 with an ordinary mixer - a pipe four-way mixer. Since the mixing effect is poor and the neutralization heat cannot be utilized for flash evaporation, the hot oil outlet 10 and the hot oil inlet 9 of the jacket 12 of the reaction kettle 11 need to be opened to heat the reaction system in the reaction kettle 11 while mixing the materials; the rest is basically the same as Example 1-2.

[0160] The obtained results are as follows:

[0161] The amount of solid coke obtained is 13.6 g, the carbon deposition rate is 5.85 Wt%, the BDMAEE content obtained by GC analysis of the crude sample is 52.7%, the BDMAEE fraction obtained is 92.3 g, the mass content of BDMAEE in this BDMAEE fraction is 99.56%, and the yield is 44.18%. The reaction time is 8 h, the reaction power consumption is about 11 KW, and the daily production capacity is 3 batches. Compared with Example 1-2, the reaction time is extended by 1 h, the energy consumption is increased by 2 KW, and the daily production capacity is reduced by 0.43 batches.

[0162] Comparative Example 1-2: Change the "control the water content of the reaction system to 0.3 - 0.35 Wt%" in steps 1) and 2) of Example 1-2 to "control the water content of the reaction system to 0.9 - 0.95 Wt%"; the rest is basically the same as Example 1-2.

[0163] The obtained results are as follows:

[0164] The amount of solid coke obtained is 4.5 g, the carbon deposition rate is 1.94 Wt%, the BDMAEE content obtained by GC analysis of the crude sample is 75.36%, the BDMAEE fraction obtained is 133.7 g, the mass content of BDMAEE in this BDMAEE fraction is 99.42%, and the yield is 64.0%. The reaction time is 8 h, the reaction power consumption is about 10 KW, and the daily production capacity is 3 batches. Compared with Example 1-2, the reaction time is extended by 1 h, the energy consumption is increased by 1 KW, and the daily production capacity is reduced by 0.43 batches.

[0165] Comparative Example 1-3: Change the "stop heating when the total amount of water distilled into the water collection tank 20 reaches 21.15 g (90% of the theoretical water output of etherification)" in step 2) of Example 1-2 to "stop heating when the total amount of water distilled into the water collection tank 20 reaches 17.63 g (75% of the theoretical water output of etherification)"; the rest is basically the same as Example 1-2.

[0166] The obtained results are as follows:

[0167] The amount of solid coke obtained is 3.9 g, the carbon deposition rate is 1.68 Wt%, the BDMAEE content obtained by GC analysis of the crude product sample is 70.84%, the BDMAEE fraction obtained is 124.5 g, the mass content of BDMAEE in this BDMAEE fraction is 99.48%, and the yield is 59.60%. The reaction time is 6 h, the power consumption of the reaction is 8 KW, and the daily production capacity is 4 batches. Although the reaction time is shortened by 1 h and the energy consumption is reduced by 1 KW compared with Examples 1-2, the yield is low.

[0168] Comparative Example 1-4: Change "stop heating when the total amount of water distilled into the water collection tank 20 reaches 21.15 g (90% of the theoretical water output of etherification)" in step 2) of Examples 1-2 to "stop heating when the total amount of water distilled into the water collection tank 20 reaches 23.1 g (98% of the theoretical water output of etherification)"; the rest is basically the same as Examples 1-2.

[0169] The results obtained are as follows:

[0170] The amount of solid coke obtained is 6.5 g, the carbon deposition rate is 2.80 Wt%, the BDMAEE content obtained by GC analysis of the crude product sample is 81.76%, the BDMAEE fraction obtained is 143.8 g, the mass content of BDMAEE in this BDMAEE fraction is 99.37%, and the yield is 68.84%. The reaction time is 9 h, the power consumption of the reaction is 11 KW, and the daily production capacity is 2.67 batches. Compared with Examples 1-2, the reaction time is extended by 2 h, the energy consumption is increased by 2 KW, and the daily production capacity is reduced by 0.76 batch.

[0171] Example 2-1: A method for synthesizing DMDEE, which sequentially performs the following steps:

[0172] 1), Continuous heat-collecting type mixing and batching:

[0173] Add 532 g (3.57 mol) of TEOA into the alkanolamine storage tank 1, add 500 g (5.0 mol) of concentrated sulfuric acid into the concentrated sulfuric acid storage tank 3, and at the same time open the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4 to feed materials into the reaction kettle 11 through the Venturi type distributor 5. The above TEOA and concentrated sulfuric acid are both fed in the same time of about 1.5 hours.

[0174] After feeding for 2 min, open the reaction liquid circulation valve 7 of the reaction kettle 11, start the reaction liquid forced circulation pump 6 to perform forced circulation on the reaction liquid in the reaction kettle 11, and mix the materials through the Venturi type distributor 5.

[0175] Control the feed flow rate to be Q 反应液 : Q TEOA : Q 浓硫酸= 1:0.26:0.15 (volume flow ratio). Metered TEOA and concentrated sulfuric acid are continuously fed into the reaction kettle 11. While continuously feeding, under the action of the Venturi-type distributor 5, flash evaporation is carried out using the reaction heat of neutralization of TEOA and concentrated sulfuric acid. Nitrogen enters the reaction system in the reaction kettle 11 through the inert gas insertion tube 16, and the moisture in the reaction system is controlled at 0.4 - 0.5 Wt% under the action of nitrogen. Without passing cooling water and only relying on the heat generated by system mixing and spontaneous heat dissipation, the temperature in the kettle is maintained not lower than 150 °C. The water and nitrogen generated by the reaction enter the condenser 18 through the air lift pipe 17. The generated water after condensation is collected and measured by the water collection tank 20. Since nitrogen cannot be condensed, it is discharged through the exhaust port 19. The collected generated water can finally be drained through the water outlet valve 21.

[0176] Continuous heat collection type mixing and batching is completed within 1.5 h.

[0177] 2), water-controlled etherification reaction:

[0178] After the feeding in step 1) is completed, only the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4 are stopped. The hot oil outlet 10 and the hot oil inlet 9 of the reaction kettle jacket 12 are opened to continue heating the reaction system in the reaction kettle 11. When the temperature shown by the thermometer 15 is 200 - 210 °C, the moisture in the reaction system is controlled at 0.4 - 0.5 Wt% under the action of the inert gas insertion tube 16. Heating is stopped and the reaction liquid forced circulation pump 6 is closed when the total amount of water distilled into the water collection tank 20 reaches 91.58 g (95% of the theoretical water output of etherification), and about 936.8 g of etherification liquid is obtained. The reaction takes 9 h, the reaction power consumption is about 12 KW, and the daily production capacity is 2.67 batches.

[0179] The theoretical water output of etherification = 532 / 149 * 1.5 * 18 = 96.4 g.

[0180] 3), neutralization:

[0181] First, 82.56 g of the etherification liquid is discharged from the discharge valve 8 for the etherification liquid obtained in step 2). After the discharging is completed, the discharge valve 8 is closed. Then, 800 g of water is added from the water inlet 13 for dilution. After the diluted liquid is discharged from the discharge valve 8, it is vacuum filtered outside the reaction kettle, and the obtained filtrate is returned to the reaction kettle 11 from the water inlet 13; 8.2 g of solid coke is obtained, and the carbon deposition rate is 1.54 Wt% based on TEOA. 360 g of solid sodium hydroxide is added from the alkali inlet 14 for neutralization to make the pH value of the system reach 9 - 10, and a crude solid-liquid mixture is obtained. The crude product is sampled for GC analysis to obtain a DMDEE content of 70.82%.

[0182] 4), solid-liquid separation:

[0183] The crude solid-liquid mixture obtained in step 3) is discharged from the discharge valve 8 and then filtered to obtain a filtrate.

[0184] 5), Rectification:

[0185] Rectify the filtrate obtained in step 4). First, rectify (under normal pressure) to separate the water fraction, and the water fraction is recycled for the next round of neutralization and dilution. Continue rectification under a pressure of 5 mmHg, condense and recover 106.2 g of the 2-morpholinoethanol fraction at 125 - 135 °C. This 2-morpholinoethanol fraction is a 2-morpholinoethanol fraction with a content of 99.2%; condense and recover 41.2 g of the transition fraction above 135 - 150 °C. This transition fraction is DMDEE with a content of less than 99%; condense and recover 253.3 g of the DMDEE fraction above 150 - 165 °C. The mass content of DMDEE in this DMDEE fraction is 99.53%, and the yield is 58.15%.

[0186] DMDEE yield = amount of DMDEE fraction / theoretical amount of DMDEE generated (calculated based on the feed amount of TEOA).

[0187] Example 2-2, A method for synthesizing DMDEE, which successively performs the following steps:

[0188] 1), Continuous heat-collecting mixed batching:

[0189] Pre-load 82.56 g of the etherification liquid prepared in Example 2-1 into the reaction kettle 11;

[0190] Open the reaction liquid circulation valve 7 of the reaction kettle 11, start the reaction liquid forced circulation pump 6 to perform forced circulation on the reaction liquid. At the same time, also open the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4, and mix the materials through the Venturi-type distributor 5.

[0191] The rest is the same as step 1) of Example 2-1.

[0192] 2), Water-controlled etherification reaction:

[0193] The same as step 2) of Example 2-1. Obtain 1019.5 g of the etherification liquid. The reaction time is 9 h, the reaction power consumption is about 12 KW, and the daily production capacity is 2.67 batches.

[0194] 3), Neutralization:

[0195] The amount of water added for dilution from the water inlet 13 remains unchanged, still 800 g; the 360 g of solid sodium hydroxide added for neutralization from the alkali inlet 14 is changed to 400 g; the rest is the same as step 3) of Example 2-1.

[0196] Obtain 10.7 g of solid coke, and the carbon deposition rate is 2.01 Wt% based on TEOA. Take a sample of the crude product for GC analysis, and the DMDEE content is 76.58%;

[0197] Steps 4) to 5) are the same as steps 4) to 5) of Example 2-1, and the obtained results are as follows:

[0198] The filtrate obtained in step 4) is rectified. First, the water fraction is separated by rectification (under normal pressure), and the water fraction is recycled for the next round of neutralization and dilution. Rectification is continued under a pressure of 5 mmHg, and 88.6 g of the 2-morpholinoethanol fraction at 125-135 °C is recovered by condensation. This 2-morpholinoethanol fraction is a 2-morpholinoethanol fraction with a content of 99.1%; 39.5 g of the transition fraction above 135-150 °C is recovered by condensation. This transition fraction is DMDEE with a content of less than 99%; 302.5 g of the DMDEE fraction above 150-165 °C is recovered by condensation. The mass content of DMDEE in this DMDEE fraction is 99.51%, and the yield is 69.44%.

[0199] Example 3-1. A method for synthesizing BMAEE, which successively performs the following steps:

[0200] 1), Continuous heat-collecting mixing and batching:

[0201] 300 g (4.0 mol) of MMEA is added to the alkanolamine storage tank 1, and 600 g (6.0 mol) of concentrated sulfuric acid is added to the concentrated sulfuric acid storage tank 3. At the same time, the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4 are opened to feed materials into the reaction kettle 11 through the Venturi-type distributor 5. The above MMEA and concentrated sulfuric acid are both fed in the same time of about 1.5 hours.

[0202] After feeding for 2 min, the reaction liquid circulation valve 7 of the reaction kettle 11 is opened, and the reaction liquid forced circulation pump 6 is started to force the reaction liquid to circulate, and the materials are mixed through the Venturi-type distributor 5.

[0203] Control the feed flow rate to be Q 反应液 : Q MMEA : Q 浓硫酸 = 1:0.18:0.18 (volume flow ratio). The measured MMEA and concentrated sulfuric acid are continuously fed into the reaction kettle 11. While continuously feeding, flash evaporation is carried out by using the reaction heat of neutralization of MMEA and concentrated sulfuric acid under the action of the Venturi-type distributor 5. Nitrogen enters the reaction system in the reaction kettle 11 through the inert gas insertion tube 16. Under the action of nitrogen, the moisture in the reaction system is controlled to be 0.2-0.3 Wt%. Without passing cooling water and only relying on the heat generated by system mixing and spontaneous heat dissipation, the temperature in the kettle is kept not lower than 150 °C. The water and nitrogen generated by the reaction enter the condenser 18 through the air lift pipe 17, and the condensed water is collected and measured by the water collection tank 20. Since nitrogen cannot be condensed, it is discharged through the exhaust port 19. The collected condensed water can finally be drained through the water outlet valve 21.

[0204] The continuous heat-collecting mixing batching is completed within 1.5 h.

[0205] 2), water control etherification reaction:

[0206] After the feeding in step 1) is completed, only the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4 are stopped, the hot oil outlet 10 and the hot oil inlet 9 of the reaction kettle jacket 12 are opened to continue heating the reaction system. When the thermometer 15 shows a temperature of 200 - 210 °C, under the action of the inert gas insertion tube 16, the water content in the reaction system is controlled at 0.2 - 0.3 Wt%. Stop heating and close the reaction liquid forced circulation pump when the total amount of water distilled into the water collection tank 20 reaches 34.2 g (95% of the theoretical water output of etherification), and about 863 g of etherification liquid is obtained. The reaction takes 9 h, the reaction power consumption is about 12 KW, and the daily production capacity is 2.67 batches.

[0207] The theoretical water output of etherification = 300 / 75 / 2*18 = 36 g.

[0208] 3), neutralization:

[0209] First, 90 g of the etherification liquid obtained in step 2) is discharged from the discharge valve 8. After the discharging is completed, the discharge valve 8 is closed. Then, 800 g of water is added from the water inlet 13 for dilution. After the diluted liquid is discharged from the discharge valve 8, it is subjected to vacuum filtration outside the reaction kettle, and the obtained filtrate is returned to the reaction kettle 11 from the water inlet 13; the amount of solid coke is 4.03 g, and the carbon deposition rate is 1.34 Wt% based on MMEA. 432 g of solid sodium hydroxide is added for neutralization to make the pH value of the system reach 9 - 10, and a crude solid-liquid mixture is obtained. The crude product is sampled for GC analysis, and the BMAEE content is 65.82%.

[0210] 4), solid-liquid separation:

[0211] The crude solid-liquid mixture obtained in step 3) is discharged from the discharge valve 8 and then filtered to obtain a filtrate.

[0212] 5), rectification:

[0213] The filtrate obtained in step 4) is rectified. First, the water fraction is separated by rectification (under normal pressure), and the water fraction is recycled for the next round of neutralization and dilution. Rectification is continued under a pressure of 5 mmHg, and 79.1 g of the MMEA fraction at 40 - 50 °C is condensed and recovered. This MMEA fraction is the MMEA fraction with a content of 99.12%; 32.5 g of the transition fraction above 50 - 70 °C is condensed and recovered. This transition fraction is the BMAEE with a content below 99%; 142.6 g of the BMAEE fraction above 70 - 90 °C is condensed and recovered. The mass content of BMAEE in this BMAEE fraction is 99.53%, and the recovery rate is 53.93%.

[0214] Yield of BMAEE = Amount of distilled BMAEE / Theoretical amount of BMAEE generated (calculated based on the feed amount of MMEA).

[0215] Example 3-2. A method for synthesizing BMAEE, which successively comprises the following steps:

[0216] 1). Continuous heat-collecting type mixing and batching:

[0217] 90 g of the etherification liquid prepared in Example 3-1 is pre-loaded into the reaction kettle 11;

[0218] Open the reaction liquid circulation valve 7 of the reaction kettle 11, start the reaction liquid forced circulation pump 6 to force the circulation of the reaction liquid. Meanwhile, also open the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4, and mix the materials through the Venturi type distributor 5. The rest is the same as step 1) of Example 3-1.

[0219] 2). Water control etherification reaction:

[0220] The same as step 2) of Example 3-1.

[0221] 953.2 g of etherification liquid is obtained, and the reaction time is 9 h.

[0222] 3). Neutralization:

[0223] The amount of water added for dilution from the water inlet 13 remains unchanged, still 800 g; the amount of sodium hydroxide added for neutralization from the alkali inlet 14 is changed from about 432 g to about 480 g; the same as step 3) of Example 3-1.

[0224] 4.53 g of solid coke is obtained, and the carbon deposition rate is 1.51 Wt%, calculated based on MMEA. The crude product is sampled for GC analysis, and the BMAEE content is 71.23%.

[0225] Steps 4) to 5) are the same as steps 4) to 5) of Example 3-1, and the obtained results are as follows:

[0226] The filtrate obtained in step 4) is rectified. First, the water fraction is separated by rectification (at atmospheric pressure), and the water fraction is recycled for the next round of neutralization and dilution. Rectification is continued under a pressure of 5 mmHg, and 68.9 g of MMEA fraction at 40 - 50 °C is condensed and recovered. This MMEA fraction is an MMEA fraction with a content of 99.1%; 31.6 g of the transition fraction above 50 - 70 °C is condensed and recovered. This transition fraction is a BMAEE with a content below 99%; 160.5 g of the BMAEE fraction above 70 - 90 °C is condensed and recovered. The mass content of BMAEE in this BMAEE fraction is 99.53%, and the yield is 60.7%.

[0227] Example 4-1. A method for synthesizing NMM, which successively comprises the following steps:

[0228] 1). Continuous heat-collecting type mixed batching:

[0229] Add 400 g (3.361 mol) of MDEA into the alkanolamine storage tank 1, add 400 g (4.0 mol) of concentrated sulfuric acid into the concentrated sulfuric acid storage tank 3. At the same time, open the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4, and feed materials into the reaction kettle 11 through the Venturi-type distributor 5. The above-mentioned MDEA and concentrated sulfuric acid both complete the feeding within about 1 hour at the same time.

[0230] After feeding for 2 min, open the reaction liquid circulation valve 7 of the reaction kettle 11, start the reaction liquid forced circulation pump 6 to force-circulate the reaction liquid in the reaction kettle 11, and mix the materials through the Venturi-type distributor 5.

[0231] Control the feeding flow rate to be Q 反应液 : Q MDEA : Q 浓硫酸 = 1:0.32:0.18 (volume flow ratio), continuously feed the measured MDEA and concentrated sulfuric acid into the reaction kettle 11. While continuously feeding, flash evaporation is carried out by using the reaction neutralization heat of MDEA and concentrated sulfuric acid under the action of the Venturi-type distributor 5. Nitrogen enters the reaction system in the reaction kettle 11 through the inert gas insertion tube 16. Under the action of nitrogen, control the water content in the reaction system to be 0.7 - 0.8 Wt%. Without passing cooling water, only relying on the heat generated by system mixing and spontaneous heat dissipation, keep the temperature in the kettle not lower than 150 °C. The water and nitrogen generated by the reaction enter the condenser 18 through the air lift pipe 17, and the condensed water is collected and measured by the water collection tank 20. Since nitrogen cannot be condensed, it is discharged through the exhaust port 19. The collected condensed water can finally be drained through the water outlet valve 21.

[0232] The continuous heat-collecting type mixed batching is completed within 1 h.

[0233] 2). Water control etherification reaction:

[0234] After the feeding in step 1) is completed, only stop the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4, open the hot oil outlet 10 and the hot oil inlet 9 of the reaction kettle jacket 12 to continue heating the reaction system in the reaction kettle 11. When the temperature shown by the thermometer 15 is 180 - 190 °C, control the water content in the reaction system to be 0.7 - 0.8 Wt% under the action of the inert gas insertion tube 16. Stop heating and close the reaction liquid forced circulation pump 6 when the total amount of water distilled into the water collection tank 20 reaches 54.45 g (90% of the theoretical water output of etherification), and obtain about 742.8 g of etherification liquid. The reaction takes 6.5 h, the reaction power consumption is about 7.5 KW, and the daily production capacity is 3.69 batches.

[0235] The theoretical water output of etherification = 400 / 119 * 18 = 60.5 g.

[0236] 3), Neutralization:

[0237] First, 24 g of the etherification liquid obtained in step 2) is discharged from the discharge valve 8. After the discharging is completed, the discharge valve 8 is closed. Then, 600 g of water is added from the water inlet 13 for dilution. After the diluted liquid is discharged from the discharge valve 8, it is subjected to vacuum filtration outside the reaction kettle. The obtained filtrate is returned to the reaction kettle 11 from the water inlet 13; the amount of solid coke obtained is 0.18 g, and the carbon deposition rate is 0.045 Wt%, calculated based on MDEA. 310 g of solid sodium hydroxide is added from the alkali inlet 14 for neutralization to make the pH value of the system reach 9 - 10, obtaining a crude solid-liquid mixture. A sample of the crude product is analyzed by GC to obtain an NMM content of 96.32%.

[0238] 4), Solid-liquid separation:

[0239] The crude solid-liquid mixture obtained in step 3) is discharged from the discharge valve 8 and then filtered to obtain a filtrate.

[0240] 5), Rectification:

[0241] The filtrate obtained in step 4) is rectified. First, the water fraction is separated by rectification (under normal pressure), and the water fraction is recycled for the next round of neutralization and dilution. Continuing rectification under normal pressure, 303.7 g of the NMM fraction at 115 - 120 °C is condensed and recovered. The mass content of NMM in this NMM fraction is 99.91%, and the recovery rate is 89.46%.

[0242] NMM recovery rate = NMM fraction amount / NMM theoretical production amount (calculated based on the MDEA feed amount).

[0243] Example 4 - 2, A method for synthesizing NMM, which successively performs the following steps:

[0244] 1), Continuous heat-collecting mixed batching:

[0245] 24 g of the etherification liquid prepared in Example 4 - 1 is pre-loaded into the reaction kettle 11;

[0246] The reaction liquid circulation valve 7 of the reaction kettle 11 is opened, and the reaction liquid forced circulation pump 6 is started to force the circulation of the reaction liquid. At the same time, the alkanolamine metering pump 2 and the concentrated sulfuric acid metering pump 4 are also opened, and the materials are mixed through the Venturi-type distributor 5.

[0247] The rest is the same as step 1) of Example 4 - 1.

[0248] 2), Water-controlled etherification reaction:

[0249] Equivalent to step 2 of Example 4-1). 766.9 g of etherified liquid was obtained. The reaction took 6.5 h, the reaction power consumption was about 7.5 KW, and the daily production capacity was 3.69 batches.

[0250] 3) Neutralization:

[0251] The amount of water added from the water feed port 13 for dilution remains unchanged at 600 g; the amount of sodium hydroxide added from the alkali feed port 14 for neutralization is changed from about 310 g to 320 g; equivalent to step 3 of Example 4-1).

[0252] The solid coke amount was 0.21 g, and the carbonization rate was 0.05 Wt%, calculated as MDEA. The crude product was sampled and analyzed by GC, and the NMM content was 98.58%;

[0253] Step 4) to step 5) are equivalent to step 4) to step 5) of Example 4-1, and the results are as follows:

[0254] The filtrate obtained in step 4) is distilled, and the water fraction is separated by distillation (normal pressure), and the water fraction is recycled for the next round of neutralization and dilution. The normal pressure distillation is continued to condense and recover 315.1g of NMM fraction at 115-120°C, and the NMM mass content in the NMM fraction is 99.92%, and the yield is 92.81%.

[0255] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A method for amine etherification reaction, characterized in that: Using an amine etherification reactor, The amine etherification reactor includes an alkanolamine storage tank (1), a concentrated sulfuric acid storage tank (3), a Venturi-type distributor (5), a reaction kettle (11), and a water collection tank (20) with an exhaust port (19); The concentrated sulfuric acid storage tank (3) is connected to the Venturi-type distributor (5) through a concentrated sulfuric acid metering pump (4), and the alkanolamine storage tank (1) is connected to the Venturi-type distributor (5) through an alkanolamine metering pump (2); The top of the reaction kettle (11) is respectively provided with a material inlet, a water inlet (13), and an alkali inlet (14); the outlet of the Venturi-type distributor (5) is directly opposite to the material inlet of the reaction kettle (11); The bottom outlet of the reaction kettle (11) is divided into two paths. One path is connected to the Venturi-type distributor (5) through a reaction liquid circulation valve (7) and a reaction liquid forced circulation pump (6) in sequence; the other path is connected to a discharging valve (8); An air lift pipe (17) is provided at the top of the reaction kettle (11), and the air lift pipe (17) is connected to the water collection tank (20) through a condenser (18); An inert gas insertion pipe (16) is connected to the inner cavity of the reaction kettle (11); A reaction kettle jacket (12) is arranged on the outer surface of the reaction kettle (11), and a coil pipe with a hot oil inlet (9) and a hot oil outlet (10) is arranged in the reaction kettle jacket (12), and the reaction kettle (11) is heated by using the reaction kettle jacket (12); The Venturi-type distributor (5) includes an inner housing (51) and an outer housing (52); The inner housing (51) is sleeved inside the outer housing (52), and the top surface of the inner housing (51) is higher than the top surface of the outer housing (52); the side wall of the inner housing (51) is hermetically connected to the top surface of the outer housing (52); The top surface of the inner housing (51) is provided with an inner housing inlet, and the outlet of the reaction liquid forced circulation pump (6) is hermetically connected to the inner housing inlet through a connecting pipe I (53), and the bottom of the inner housing (51) is open; the open end is located in the inner cavity of the outer housing (52); An outer housing inlet one and an outer housing inlet two are respectively arranged on the side wall of the outer housing (52); the outlet of the alkanolamine metering pump (2) is hermetically connected to the outer housing inlet one through a connecting pipe II (54), and the outlet of the concentrated sulfuric acid metering pump (4) is hermetically connected to the outer housing inlet two through a connecting pipe III (55); The outer housing inlet one and the outer housing inlet two are at the same height and are both above the bottom open end of the inner housing (51); therefore, the materials are mixed in the inner cavity of the outer housing (52) below the bottom open end of the inner housing (51); The bottom surface of the outer housing (52) is provided with a material outlet, one end of a connecting pipe IV (56) is hermetically connected to the material outlet, and the other end is hermetically connected to the material inlet of the reaction kettle (11); The amine etherification reaction method: Using alkanolamine, concentrated sulfuric acid, and alkali as reaction raw materials, includes the following steps: 1), Continuous heat collection type mixing and batching: Open the reaction liquid circulation valve (7) of the reaction kettle (11) pre-filled with etherification liquid, start the reaction liquid forced circulation pump (6), the etherification liquid returns to the reaction kettle (11) after passing through the Venturi-type distributor (5), and the etherification liquid is forced to circulate; Add alkanolamine into the alkanolamine storage tank (1), add concentrated sulfuric acid into the concentrated sulfuric acid storage tank (3), open the alkanolamine metering pump (2) and the concentrated sulfuric acid metering pump (4) while opening the reaction liquid circulation valve (7), and feed materials into the reaction kettle (11) through the Venturi-type distributor (5). The molar ratio of sulfuric acid to alkanolamine is 1.0 - 2.0:1, and the flow rates are Q 反应液 , Q 醇胺 , Q 浓硫酸 and are controlled according to the set ratio; the metered alkanolamine and concentrated sulfuric acid continuously enter the reaction kettle (11). While continuously feeding, flash evaporation is carried out in the reaction kettle (11) by using the reaction heat of neutralization between the alkanolamine and the concentrated sulfuric acid under the action of the Venturi-type distributor (5), and the moisture content in the reaction system of the reaction kettle (11) is controlled to be 0.03 - 0.9 Wt% by introducing inert gas; The water and gas generated by the reaction enter the condenser (18) through the air lift pipe (17), and the condensed water is collected and measured by the water collection tank (20), and the exhaust gas is discharged through the exhaust port (19); after the feeding of the alkanolamine and concentrated sulfuric acid is completed, stop the alkanolamine metering pump (2) and the concentrated sulfuric acid metering pump (4). 2), water-controlled etherification reaction: After the feeding in step 1) is completed, open the hot oil outlet (10) and the hot oil inlet (9) of the reaction kettle jacket (12) to continue heating the reaction system, control the reaction temperature to be 150-220 °C, and continue to control the water content in the reaction system in the reaction kettle (11) to be 0.03-0.9 Wt%. When the total amount of water distilled into the water collection tank (20) reaches 50-100% of the theoretical water output of etherification, stop the reaction to obtain the etherification liquid. 3), neutralization: First, release a pre-added amount of the etherification liquid from the discharge valve (8) for the etherification liquid obtained in step 2). After the discharging is completed, close the discharge valve (8), then add water from the water inlet (13) for dilution, and then add solid base from the base inlet (14) for neutralization to make the pH value of the system reach 9-10 to obtain a solid-liquid mixture. 4), solid-liquid separation: The solid-liquid mixture obtained in step 3) is discharged from the discharge valve (8) and then filtered to obtain the filtrate. 5), rectification: The filtrate obtained in step 4) is rectified. First, the water fraction is obtained by rectification separation, and then the amine ether fraction is obtained by rectification separation.

2. The amine etherification reaction method according to claim 1, characterized in that: In the said step 1): The weight of the etherification liquid pre-loaded into the reaction kettle (11) is 0-20 Wt% of the sum of the weights of the alkanolamine and concentrated sulfuric acid as raw materials; Flow control is Q 反应液 : Q 醇胺 : Q 浓硫酸 = 1: 0.04~3: 0.04~3.

3. The amine etherification reaction method according to claim 2, characterized in that: When the total amount of water distilled into the water collection tank (20) reaches 90-95% of the theoretical water output of etherification, stop the reaction.

4. The amine etherification reaction method according to claim 3, characterized in that: The weight of the etherification liquid pre-loaded into the reaction kettle (11) is 3-10 Wt% of the sum of the weights of the alkanolamine and concentrated sulfuric acid as raw materials.

5. The amine etherification reaction method according to any one of claims 1-4, characterized in that: A thermometer (15) is provided inside the reaction kettle (11); a water outlet valve (21) is provided at the bottom of the water collection tank (20).

6. The amine etherification reaction method according to claim 5, characterized in that: The alkanolamine and concentrated sulfuric acid are mixed under the action of the Venturi type distributor (5); flash evaporation is carried out by using the heat of neutralization of the alkanolamine and concentrated sulfuric acid under the action of the Venturi type distributor (5); Drain water through the water outlet valve (21).

7. The amine etherification reaction method according to claim 6, wherein: The inner shell (51) is an inverted conical cylinder; The outer shell (52) is composed of an integrated large cylinder (521), an inverted conical cylinder (522), a small cylinder (523), and a conical cylinder (524) arranged in sequence from top to bottom; The inner diameter of the large cylinder (521) = the top inner diameter of the inverted conical cylinder (522), and the bottom inner diameter of the inverted conical cylinder (522) = the inner diameter of the small cylinder (523) = the top inner diameter of the conical cylinder (524); An outer shell feed port one and an outer shell feed port two are provided on the side wall of the inverted conical cylinder (522); The bottom open position of the inner housing (51) corresponds to the height position of the inverted conical cylinder (522).

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