Process for the synthesis of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]- ethylamine

Abstract

This invention relates to a method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, comprising the following steps: a) reacting 2-[2-(dimethylamino)ethoxy]ethanol with potassium hydroxide at 80℃~120℃ for 2h~6h; b) cooling the reaction solution from step a) to -5℃~5℃, then adding allyl chloride dropwise, maintaining the temperature at -5℃~5℃ for 1h~4h, and then raising the temperature to 10℃~35℃ for another 8h~30h. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine provided by this invention is simple, has few reaction impurities, produces a high-purity product with high yield, low energy consumption, and a simple post-processing procedure, making it suitable for industrial production and highly economical.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology and relates to a method for synthesizing amino-olefin compounds containing ether bonds, particularly a method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine. Background Technology

[0002] Olefin compounds are used as important intermediates in chemical synthesis due to the reactivity of their carbon-carbon double bonds and their wide range of reactions. Introducing ether bonds into the molecule can effectively improve the solubility and stability of the product. Amine functional groups are widely present in organisms; therefore, the introduction of amine groups is also an important means in the pharmaceutical industry to adjust the solubility and stability of drugs. Compounds combining olefins, ether bonds, and amine groups integrate the characteristics of all three functional groups, resulting in a wider range of applications. In recent years, with the continuous development of lithium-ion battery research, various compounds have been used in electrolytes to improve battery performance. Patent CN107732304A discloses several organosilicon amine compounds synthesized based on ether-containing olefin amine compounds, demonstrating that these compounds, as electrolyte additives, can effectively reduce impedance, improve cycle stability, and extend battery life. However, among the various currently disclosed synthetic methods, those that effectively combine ether bonds, olefins, and amine groups remain relatively rare.

[0003] Currently, most publicly available synthetic routes for amino-olefin compounds containing ether bonds are based on affinity substitution reactions. In Science China Chemistry Vol. 56 No. 6739-745, elemental sodium is used as a deprotonating agent to react with the corresponding alcohol to generate the corresponding sodium alkoxide, which then reacts with the corresponding brominated olefin to generate the corresponding product. However, this method uses highly reactive elemental sodium, posing a significant fire hazard and violating safety principles in industrial production. Furthermore, the bromide ions generated during the reaction easily form byproducts, resulting in low yields and product purity. CN115160205A uses toluene as a solvent in the preparation process, replacing the deprotonating agent with the milder sodium tert-butoxide, making the synthetic reaction more controllable and reducing the risk of thermal runaway. However, toluene is a controlled substance and difficult to procure, and industrial recovery of toluene must also be considered; therefore, this method is not industrially feasible.

[0004] N,N-Dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine is an amino-olefin compound containing an ether bond. It can be used to synthesize electrolyte materials for lithium-ion batteries (CN115340566A), and can also be used as a raw material for the synthesis of polymers such as cellulose esters or polyesters, or as a solvent in the synthesis of industrial products such as adhesives and paints. Its structural formula is as follows:

[0005]

[0006] Currently, there are very few reports on the synthesis methods of this compound. Summary of the Invention

[0007] Based on this, the purpose of this invention is to provide a method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine.

[0008] The technical solutions for achieving the above objectives include the following.

[0009] This invention provides a method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, comprising the following steps:

[0010] a) 2-[2-(dimethylamino)ethoxy]ethanol reacts with potassium hydroxide at a temperature of 80℃~120℃ for 2h~6h;

[0011] b) Cool the reaction solution from step a) to -5℃ to 5℃, then add allyl chloride dropwise, maintain the temperature at -5℃ to 5℃ for 1h to 4h, then raise the temperature to 10℃ to 35℃ and react for another 8h to 30h.

[0012] The present invention has the following beneficial effects:

[0013] The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine provided by this invention is simple, has few reaction impurities, produces high-purity products, has high yields, low energy consumption, and a simple post-processing procedure, making it suitable for industrial production and highly economical.

[0014] This invention uses 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride as raw materials for the reaction, which has better reaction effect, fewer reaction impurities, and significantly improved product purity and yield compared with the conventionally used allyl bromide.

[0015] The reaction of 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride in this invention, under the action of a specific base (potassium hydroxide), significantly improves the purity and yield of the product compared to conventionally used sodium tert-butoxide.

[0016] The reaction of 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride in this invention does not require a solvent. The reaction is carried out under solvent-free conditions, which not only improves the purity and yield of the product, but also avoids the risks and various costs associated with using toxic solvents such as toluene and solvent recovery. Attached Figure Description

[0017] Figure 1The gas chromatogram of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine prepared in Example 1.

[0018] Figure 2 The 1H NMR spectrum of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine.

[0019] Figure 3 The gas chromatogram of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine prepared in Example 2.

[0020] Figure 4 The gas chromatogram of N,N-dimethyl-2-propyl-2-enoxyethanolamine prepared in Example 4 is shown.

[0021] Figure 5 The 1H NMR spectrum of N,N-dimethyl-2-propyl-2-enoxyethanolamine prepared in Example 4. Detailed Implementation

[0022] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0023] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0024] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0025] Furthermore, as used herein, the term "or" is an inclusive "or" sign and is equivalent to the term "and / or" unless the context clearly specifies otherwise. The term "based on" is not exclusive and allows for basing on other factors not described unless the context clearly specifies otherwise. Additionally, throughout the specification, the meanings of "an," "a," and "the" include plural indicators. The meaning of "in" includes both "in" and "on."

[0026] Some of the embodiments involve a method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, comprising the following steps:

[0027] a) 2-[2-(dimethylamino)ethoxy]ethanol reacts with potassium hydroxide at a temperature of 80℃~120℃ for 2h~6h;

[0028] b) Cool the reaction solution from step a) to -5℃ to 5℃, then add allyl chloride dropwise, maintain the temperature at -5℃ to 5℃ for 1h to 4h, then raise the temperature to 10℃ to 35℃ and react for another 8h to 30h.

[0029] Through extensive experimental research, the inventors of this invention discovered that the reaction of 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride using these two raw materials yields better results and fewer impurities compared to conventionally used allyl bromide, resulting in significantly improved product purity and yield. Furthermore, the reaction of 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride using a specific base (potassium hydroxide) significantly improves product purity and yield compared to conventionally used sodium tert-butoxide. Moreover, the reaction of 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride in this invention requires no solvent, and it was unexpectedly discovered that reacting under solvent-free conditions can actually significantly improve product purity and yield.

[0030] In some preferred embodiments, the reaction temperature of step a) is 100°C to 110°C, for example, 100°C, 105°C, 110°C, etc.

[0031] In some preferred embodiments, the reaction time for step a) is 3 to 4 hours.

[0032] In some preferred embodiments, the reaction solution of step a) is cooled to -2°C to 2°C, then allyl chloride is added dropwise, and the reaction is maintained at -2°C to 2°C for 2 to 3 hours. The temperature is then raised to 20°C to 30°C and the reaction is continued for 12 to 20 hours.

[0033] In some preferred embodiments, the molar ratio of 2-[2-(dimethylamino)ethoxy]ethanol, potassium hydroxide and allyl chloride is 1:(1-5):(1-3).

[0034] In some preferred embodiments, the molar ratio of 2-[2-(dimethylamino)ethoxy]ethanol, potassium hydroxide and allyl chloride is 1:(1.2-3):(1.1-2).

[0035] In some preferred embodiments, the molar ratio of 2-[2-(dimethylamino)ethoxy]ethanol, potassium hydroxide and allyl chloride is 1:(1.3-1.8):(1.2-1.5).

[0036] In some preferred embodiments, the reactions in steps a) and b) are both carried out under an inert gas atmosphere.

[0037] In some preferred embodiments, the method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine further includes post-treating the reaction mixture after step b) as follows:

[0038] (1) Filter the reaction mixture, wash the residue with an organic solvent, collect the filtrate and washing liquid to obtain an organic solution containing the target product;

[0039] (2) The organic solution containing the target product is washed with alkaline water, dried and then concentrated to obtain a concentrated solution;

[0040] (3) The concentrated liquid is subjected to vacuum distillation, and the fraction at 36℃-40℃ is collected to obtain N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine.

[0041] In some embodiments, step (2) includes: washing the organic solution containing the target product with alkaline water, extracting the resulting aqueous phase with an organic solvent, combining the extracted organic phase with the organic solution containing the target product, drying, concentrating, and obtaining a concentrated solution.

[0042] In some preferred embodiments, the organic solvent in step (1) is selected from one or more of n-hexane, cyclohexane, ethyl acetate, and dichloromethane.

[0043] In some preferred embodiments, the alkaline solution in step (2) is a saturated sodium carbonate solution and / or a saturated sodium bicarbonate solution.

[0044] In some preferred embodiments, the organic solvent used for extraction in step (2) is preferably one or more of n-hexane, cyclohexane, ethyl acetate, and dichloromethane.

[0045] In some preferred embodiments, the drying in step (2) is performed with anhydrous sodium sulfate and / or anhydrous magnesium sulfate.

[0046] In some preferred embodiments, the concentration pressure is 3 kPa to 8 kPa, such as 4 kPa, 5 kPa, 6 kPa, etc.

[0047] In some preferred embodiments, the concentration temperature is 30°C to 40°C, such as 30°C, 35°C, 40°C, etc.

[0048] In some preferred embodiments, the pressure of the vacuum distillation is 20 Pa to 120 Pa, such as 20 Pa, 25 Pa, 30 Pa, 40 Pa, etc.

[0049] In some preferred embodiments, the temperature of the vacuum distillation is 40°C to 70°C (e.g., 40°C, 50°C, 60°C, etc.).

[0050] The present invention will be further described in detail below with reference to specific embodiments.

[0051] Example 1: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0052] Under argon protection, 1.5 mol of 2-[2-(dimethylamino)ethoxy]ethanol (203.9 g) was added to a 1 L three-necked round-bottom flask equipped with a condenser, electric stirrer and constant pressure dropping funnel. Then, 2.25 mol of solid KOH (148.8 g) was added, and mechanical stirring was turned on. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then, it was placed in an ice bath (0 °C) to cool. After 0.5 h, 2 mol of allyl chloride (156.9 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2.5 h. Then, the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (100 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (100 ml), and then the aqueous phase after washing was extracted three times with n-hexane (100 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C. The fraction collected at 36°C-40°C yielded 187.3 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 72%. The sample was analyzed and the purity was 99%.

[0053] The gas chromatogram of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine obtained in Example 1 is shown below. Figure 1 As shown, 1 H NMR image as follows Figure 2 As shown.

[0054] Example 2: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0055] Under argon protection, 1.5 mol of 2-[2-(dimethylamino)ethoxy]ethanol (204.0 g) was added to a 1 L three-necked round-bottom flask equipped with a condenser, electric stirrer and constant pressure dropping funnel. Then, 2.25 mol of solid KOH (148.7 g) was added, and mechanical stirring was turned on. The three-necked round-bottom flask was placed in an oil bath and heated to 100 °C for 3.5 h. Then, it was placed in an ice bath (0 °C) to cool. After 0.5 h, 2 mol of allyl chloride (156.3 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2 h. Then, the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (100 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (100 ml), and then the aqueous phase after washing was extracted three times with n-hexane (100 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 40°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 50°C. The fraction collected at 36°C-40°C yielded 183.0 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 70% and a purity of 99%.

[0056] The gas chromatogram of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine obtained in Example 2 is shown below. Figure 3 As shown.

[0057] Example 3: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0058] Under argon protection, 0.375 mol of 2-[2-(dimethylamino)ethoxy]ethanol (51.0 g) was added to a 250 ml three-necked round-bottom flask equipped with a condenser, electric stirrer, and constant-pressure dropping funnel. Then, 0.563 mol of solid sodium tert-butoxide (55.2 g) was added, and mechanical stirring was started. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then, it was placed in an ice bath (0 °C) to cool. After 0.5 h, 0.5 mol of allyl chloride (39.1 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2.5 h. Then, the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (50 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (50 ml), and then the aqueous phase after washing was extracted three times with n-hexane (50 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C. The fraction collected at 36°C-40°C yielded 26.5 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 38%. The sample was analyzed and the purity was 96%.

[0059] Example 4: Preparation of N,N-dimethyl-2-propyl-2-enoxyethanolamine

[0060] Under argon protection, 0.375 mol N,N-dimethylethanolamine (34.2 g) was added to a 250 ml three-necked round-bottom flask equipped with a condenser, electric stirrer and constant pressure dropping funnel. Then, 0.563 mol solid KOH (37.6 g) was added, and mechanical stirring was turned on. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then it was placed in an ice bath (0 °C) to cool. After 0.5 h, 0.5 mol allyl chloride (39.5 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2.5 h. Then the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (50 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (50 ml), and then the aqueous phase after washing was extracted three times with n-hexane (50 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation using a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C, and the fraction collected at 28°C-34°C was used to obtain 21.6 g of N,N-dimethyl-2-propyl-2-enoxyethanolamine, with a yield of 41.5%. The purity was 98.7% after sampling and analysis.

[0061] The gas chromatogram of N,N-dimethyl-2-propyl-2-enoxyethanolamine obtained in Example 4 is shown below. Figure 4 As shown, 1 HNMR image as follows Figure 5 As shown.

[0062] Example 5: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0063] Under argon protection, 1.5 mol of 2-[2-(dimethylamino)ethoxy]ethanol (203.7 g) was added to a 1 L three-necked round-bottom flask equipped with a condenser, electric stirrer and constant pressure dropping funnel. Then, 2.25 mol of solid KOH (148.5 g) was added, and mechanical stirring was turned on. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then, it was placed in an ice bath (0 °C) to cool. After 0.5 h, 2 mol of bromopropene (246.9 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2.5 h. Then, the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (100 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (100 ml), and then the aqueous phase after washing was extracted three times with n-hexane (100 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C. The fraction collected at 36°C-40°C yielded 152.5 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 41%. The sample was analyzed and the purity was 95%.

[0064] Example 6: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0065] Under argon protection, 100 ml of toluene and 40.9 g of 2-[2-(dimethylamino)ethoxy]ethanol (0.3 mol) were added to a 500 ml three-necked round-bottom flask equipped with a condenser, electric stirrer and constant pressure dropping funnel. Then, 0.45 mol of solid KOH (29.8 g) was added, and mechanical stirring was turned on. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then it was placed in an ice bath (0 °C) to cool. After 0.5 h, 0.4 mol of allyl chloride (31.8 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2.5 h. Then the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (50 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (50 ml), and then the aqueous phase after washing was extracted three times with n-hexane (50 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C. The fraction collected at 36°C-40°C yielded 29 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 54.6%. The sample was analyzed, and the purity was 98.8%.

[0066] Example 7: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0067] Under argon protection, 100 ml of tetrahydrofuran and 0.3 mol of 2-[2-(dimethylamino)ethoxy]ethanol (41.0 g) were added to a 500 ml three-necked round-bottom flask equipped with a condenser, electric stirrer and constant pressure dropping funnel. Then, 0.45 mol of solid KOH (30.1 g) was added, and mechanical stirring was turned on. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then it was placed in an ice bath (0 °C) to cool. After 0.5 h, 0.4 mol of allyl chloride (31.3 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2.5 h. Then the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (50 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (50 ml), and then the aqueous phase after washing was extracted three times with n-hexane (50 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C. The fraction collected at 36°C-40°C yielded 25.7 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 48%. The sample was analyzed, and the purity was 98.7%.

[0068] Example 8: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0069] Under argon protection, 1.5 mol of 2-[2-(dimethylamino)ethoxy]ethanol (203.9 g) was added to a 1 L three-necked round-bottom flask equipped with a condenser, electric stirrer and constant pressure dropping funnel. Then, 2.25 mol of solid sodium hydroxide (91.8 g) was added, and mechanical stirring was turned on. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then, it was placed in an ice bath (0 °C) to cool. After 0.5 h, 2 mol of allyl chloride (156.9 g) was slowly added dropwise and reacted at the ice bath temperature (0 °C) for 2.5 h. Then, the temperature was raised to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (100 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (100 ml), and then the aqueous phase after washing was extracted three times with n-hexane (100 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C. The fraction collected at 36°C-40°C yielded 95.2 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 32.9%. The sample was analyzed, and the purity was 93.8%.

[0070] Example 9: Preparation of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine

[0071] Under argon protection, 0.301 mol of 2-[2-(dimethylamino)ethoxy]ethanol (41.0 g) was added to a 250 ml three-necked round-bottom flask equipped with a condenser, electric stirrer, and constant-pressure dropping funnel. Then, 0.453 mol of KOH (29.9 g) was added, and mechanical stirring was started. The three-necked round-bottom flask was placed in an oil bath and heated to 110 °C for 3 h. Then, it was placed in an ice bath (0 °C) to cool. After 0.5 h, 0.4 mol of allyl chloride (31.4 g) was slowly added dropwise. After the addition was completed, the temperature was raised to 70 °C and reacted for 2.5 h. Then, the temperature was lowered to room temperature and stirred for 16 h. After the reaction was stopped, the reaction mixture was filtered under reduced pressure using a water pump to remove unreacted solid raw materials and solid byproducts generated during the reaction. The filter residue was washed with n-hexane (50 ml), and the filtrate and n-hexane washing liquid were combined. The resulting organic solution containing the target product was washed twice with saturated sodium bicarbonate solution (50 ml), and then the aqueous phase after washing was extracted three times with n-hexane (50 ml). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation in a rotary evaporator at 35°C water temperature and 5 kPa pressure. The solution was then distilled under reduced pressure (25 Pa) using an oil pump at an oil bath temperature of 60°C. The fraction collected at 36°C-40°C yielded 15.73 g of N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, with a yield of 28%. The sample was analyzed and the purity was 95%.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine, characterized in that, Includes the following steps: a) 2-[2-(dimethylamino)ethoxy]ethanol reacts with potassium hydroxide at a temperature of 80℃~120℃ for 2h~6h; b) Cool the reaction solution from step a) to -5℃~5℃, then add allyl chloride dropwise, maintain the temperature at -5℃~5℃ for 1h~4h, then raise the temperature to 10℃~35℃ and react for another 8h~30h. The molar ratio of 2-[2-(dimethylamino)ethoxy]ethanol, potassium hydroxide and allyl chloride is 1:(1-5):(1-3); Both steps a) and b) were carried out under inert gas protection and without solvent.

2. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 1, characterized in that, The reaction temperature for step a) is 100℃~110℃.

3. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 1, characterized in that, The reaction time for step a) is 3 to 4 hours.

4. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 1, characterized in that, Cool the reaction solution from step a) to -2℃ to 2℃, then add allyl chloride dropwise, maintain the temperature at -2℃ to 2℃ for 2h to 3h, then raise the temperature to 20℃ to 30℃ and react for another 12h to 20h.

5. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 1, characterized in that, The molar ratio of 2-[2-(dimethylamino)ethoxy]ethanol, potassium hydroxide and allyl chloride is 1:(1.2-3):(1.1-2).

6. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 5, characterized in that, The molar ratio of 2-[2-(dimethylamino)ethoxy]ethanol, potassium hydroxide and allyl chloride is 1:(1.3-1.8):(1.2-1.5).

7. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to any one of claims 1-6, characterized in that, This also includes the following post-treatment of the reaction mixture after step b): (1) Filter the reaction mixture, wash the residue with an organic solvent, collect the filtrate and washing liquid to obtain an organic solution containing the target product; (2) The organic solution containing the target product is washed with alkaline water, dried and then concentrated to obtain a concentrated solution; (3) The concentrated liquid is subjected to vacuum distillation, and the fraction at 36℃-40℃ is collected to obtain N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine.

8. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 7, characterized in that, The organic solvent used in step (1) is selected from one or more of n-hexane, cyclohexane, ethyl acetate, and dichloromethane; And / or, the alkaline solution in step (2) is a saturated sodium carbonate solution and / or a saturated sodium bicarbonate solution; And / or, the drying in step (2) is drying with anhydrous sodium sulfate and / or anhydrous magnesium sulfate; And / or, the concentration pressure in step (2) is 3 kPa to 8 kPa; And / or, the concentration temperature in step (2) is 30°C to 40°C; And / or, the pressure of vacuum distillation in step (3) is 20 Pa to 120 Pa; And / or, the temperature of vacuum distillation in step (3) is 40℃~70℃.

9. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 7, characterized in that, Step (2) includes: washing the organic solution containing the target product with alkaline water, extracting the resulting aqueous phase with an organic solvent, combining the extracted organic phase with the organic solution containing the target product, drying, concentrating, and obtaining a concentrated solution.

10. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 9, characterized in that, The organic solvent used for extraction is one or more of n-hexane, cyclohexane, ethyl acetate, and dichloromethane.

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