Synthesis method of N, N-dimethyl-2-[2-(2-propylene-1-yloxy) ethyoxyl]-ethylamine

Abstract

The invention relates to a synthesis method of N, N-dimethyl-2-[2-(2-propylene-1-yloxy) ethyoxyl]-ethylamine, which comprises the following steps of: a) reacting 2-[2-(dimethylamino) ethyoxyl] ethanol with potassium hydroxide at the temperature of between 80 and 120 DEG C for 2 to 6 hours; and b) cooling the reaction liquid in the step a) to-5 DEG C to 5 DEG C, dropwise adding chloropropene, maintaining the temperature to-5 DEG C to 5 DEG C, reacting for 1-4 hours, heating to 10-35 DEG C, and reacting for 8-30 hours. The synthesis method of the N, N-dimethyl-2-[2-(2-propylene-1-yloxy) ethyoxyl]-ethylamine provided by the invention is simple, few in reaction impurities, high in product purity, high in yield, low in energy consumption, simple in post-treatment process, suitable for industrial production and high in economic benefit.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis and relates to a method for synthesizing amino olefin compounds containing ether bonds, in particular to a method for synthesizing N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine. Background Art

[0002] Olefin compounds are used as important chemical synthesis intermediates due to the reactivity of their carbon-carbon double bonds and a wide range of reaction types. At the same time, the introduction of ether bonds in the molecules can effectively improve the solubility and stability of the products. Amine functional groups are widely present in organisms, so the introduction of amine groups is also an important means for adjusting the solubility and stability of drugs in the pharmaceutical industry. Compounds combining olefins, ether bonds and amine groups combine the characteristics of the three functional groups and have a wider range of applications. In recent years, with the continuous deepening of research on lithium-ion batteries, different compounds have been used in electrolytes to improve the performance of batteries. Among them, patent CN107732304A discloses a variety of organosilicon amine compounds synthesized based on olefin amine compounds containing ether bonds, which proves that such compounds can effectively reduce impedance as electrolyte additives, improve cycle stability, and extend the service life of batteries. However, among the various synthetic methods currently disclosed, synthetic methods that effectively combine the three functional groups of ether bonds, olefins and amine groups are still relatively rare.

[0003] In the currently disclosed technology, the synthetic route of the amino olefin compounds containing ether bonds is mostly based on affinity substitution reaction. In Science China Chemistry Vol.56 No.6739-745, after using elemental metal sodium as a deprotonating agent to react with the corresponding alcohol compound to generate the corresponding sodium alcoholate, it is reacted with the corresponding bromoolefin to generate the corresponding product. However, the sodium elemental reaction activity used in this method is high, the fire risk is large, and it is contrary to the safety principle in industrial production. At the same time, the bromide ions produced in the reaction are also easy to form by-products, resulting in the yield and product purity of the method being relatively low. In CN115160205A, toluene is used as a solvent in the preparation process, and the deprotonating agent is replaced with a relatively mild sodium tert-butoxide, so that the synthesis reaction process is more controllable, and the risk of thermal runaway is reduced, but toluene is difficult to purchase as a controlled product, and the recovery of toluene needs to be considered industrially, so this method is not feasible in industry.

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

[0005]

[0006] At present, there are few reports on the synthesis method of this compound. Summary of the invention

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

[0008] The technical solutions for achieving the above-mentioned purpose include the following.

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

[0010] a) reacting 2-[2-(dimethylamino)ethoxy]ethanol with potassium hydroxide at a temperature of 80°C to 120°C for 2h to 6h;

[0011] b) Cooling the reaction solution of step a) to -5°C to 5°C, then adding allyl chloride dropwise, maintaining the temperature at -5°C to 5°C for reaction for 1h to 4h, raising the temperature to 10°C to 35°C and reacting for another 8h to 30h.

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

[0013] The synthesis method of N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine provided by the invention is simple, has few reaction impurities, high product purity, high yield, low energy consumption, simple post-treatment process, is suitable for industrial production, and has high economic benefits.

[0014] The invention uses 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride as raw materials for reaction, and has better reaction effect and less reaction impurities than conventionally used allyl bromide, and significantly improves product purity and yield.

[0015] The 2-[2-(dimethylamino)ethoxy]ethanol of the present invention and allyl chloride react under the action of a specific base (potassium hydroxide), and compared with conventionally used sodium tert-butoxide, the purity and yield of the product are significantly improved.

[0016] The reaction of 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride does not require a solvent and is carried out without a solvent, which not only improves the purity and yield of the product but also avoids the risks caused by using toxic solvents such as toluene and various costs for solvent recovery. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0020] Figure 4 This is the gas chromatogram of N,N-dimethyl-2-propyl-2-enyloxyethanolamine prepared in Example 4.

[0021] Figure 5 This is the H NMR spectrum of N,N-dimethyl-2-propyl-2-enyloxyethanolamine prepared in Example 4. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0023] The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or conditions recommended by the manufacturers. The various commonly used chemical reagents used in the examples are all commercially available products.

[0024] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0025] In addition, as used in the present invention, the term "or" is an inclusive "or" symbol and is equivalent to the term "and / or", unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on other factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meanings of "a", "an", and "the" include plural referents. The meaning of "in..." includes "in..." and "on...".

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

[0027] a) reacting 2-[2-(dimethylamino)ethoxy]ethanol with potassium hydroxide at a temperature of 80°C to 120°C for 2h to 6h;

[0028] b) Cooling the reaction solution of step a) to -5°C to 5°C, then adding allyl chloride dropwise, maintaining the temperature at -5°C to 5°C for reaction for 1h to 4h, raising the temperature to 10°C to 35°C and reacting for another 8h to 30h.

[0029] The inventors of the present invention have found through a large number of experimental studies that the present invention uses 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride as raw materials for reaction, and has better reaction effect than conventionally used allyl bromide, less reaction impurities, and significantly improved product purity and yield; the 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride of the present invention react under the action of a specific base (potassium hydroxide), and the product purity and yield are significantly improved compared to conventionally used sodium tert-butoxide; the reaction of 2-[2-(dimethylamino)ethoxy]ethanol and allyl chloride of the present invention does not require a solvent, and it is unexpectedly found that the reaction can significantly improve the product purity and yield under the condition of no solvent.

[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 of step a) is 3 h to 4 h.

[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, the temperature is maintained at -2°C to 2°C for 2h to 3h, and then the temperature is raised to 20°C to 30°C for further 12h to 20h.

[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 of step a) and step b) are both carried out under the protection of an inert gas.

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

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

[0039] (2) washing the organic solution containing the target product with alkaline water, drying it, and then concentrating it to obtain a concentrated solution;

[0040] (3) The concentrated liquid is subjected to reduced pressure distillation, and the fraction at 36° C. to 40° C. is collected to obtain the N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine.

[0041] In some of the embodiments, step (2) comprises: 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, and concentrating to obtain 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 water 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 using anhydrous sodium sulfate and / or anhydrous magnesium sulfate.

[0046] In some preferred embodiments, the concentrated pressure is 3KPa to 8KPa, such as 4KPa, 5KPa, 6KPa, 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 reduced pressure distillation is 20Pa to 120Pa, such as 20Pa, 25Pa, 30Pa, 40Pa, etc.

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

[0050] The present invention is 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 1L three-necked round-bottom flask equipped with a condenser, an electric stirrer and a constant pressure dropping funnel, and then 2.25 mol of solid KOH (148.8 g) was added. The mechanical stirring was turned on, and the three-necked round-bottom flask was placed in an oil bath and heated to 110°C for reaction for 3 h. Then, it was placed in an ice bath (0°C) for cooling. 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 stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (100 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (100 ml), and the washed aqueous phase was extracted 3 times with n-hexane (100 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was subjected to rotary evaporation to remove the solvent at a water temperature of 35°C and a pressure of 5KPa. The filtrate was distilled under reduced pressure (25Pa) with an oil pump, and the oil bath temperature was 60°C. The fractions at 36°C-40°C were collected to obtain 187.3 g of N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine with a yield of 72%. The purity was 99% after sampling and analysis.

[0053] The gas chromatogram of N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine obtained in Example 1 is as follows: Figure 1 As shown, 1 H NMR images Figure 2 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 1L three-necked round-bottom flask equipped with a condenser, an electric stirrer and a constant pressure dropping funnel, and then 2.25 mol of solid KOH (148.7 g) was added. The mechanical stirring was turned on, and the three-necked round-bottom flask was placed in an oil bath and heated to 100°C for reaction for 3.5 h. Then, it was placed in an ice bath (0°C) for cooling. 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 stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (100 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (100 ml), and the washed aqueous phase was extracted 3 times with n-hexane (100 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was subjected to rotary evaporation to remove the solvent at a water temperature of 40°C and a pressure of 5KPa. The filtrate was distilled under reduced pressure (25Pa) with an oil pump, and the oil bath temperature was 50°C. The fractions at 36°C-40°C were collected to obtain 183.0 g of N,N-dimethyl-2-[2-(2-propylene-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-propylene-1-yloxy)ethoxy]-ethylamine obtained in Example 2 is as follows: Figure 3 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, an electric stirrer and a constant pressure dropping funnel, and then 0.563 mol of solid sodium tert-butoxide (55.2 g) was added. The mechanical stirring was turned on, and the three-necked round-bottom flask was placed in an oil bath and heated to 110°C for reaction for 3 h. Then, it was placed in an ice bath (0°C) for cooling. 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 stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (50 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (50 ml), and the washed aqueous phase was extracted 3 times with n-hexane (50 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was evaporated with a rotary evaporator at a water temperature of 35°C and a pressure of 5KPa to remove the solvent. The filtrate was distilled under reduced pressure (25Pa) with an oil pump, and the oil bath temperature was 60°C. The fractions at 36°C-40°C were collected to obtain 26.5 g of N,N-dimethyl-2-[2-(2-propylene-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-enyloxyethanolamine

[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, an electric stirrer and a constant pressure dropping funnel, and 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 reaction for 3 h, and then placed in an ice bath (0°C) for cooling. After 0.5 h, 0.5 mol of allyl chloride (39.5 g) was slowly added dropwise and reacted at ice bath temperature (0°C) for 2.5 h, then heated to room temperature and stirred for 16 h. After stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (50 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (50 ml), and the washed aqueous phase was extracted 3 times with n-hexane (50 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was evaporated with a rotary evaporator at a water temperature of 35°C and a pressure of 5KPa to remove the solvent, and distilled under reduced pressure (25Pa) with an oil pump, the oil bath temperature was 60°C, and the fraction of 28°C-34°C was collected to obtain 21.6 g of N,N-dimethyl-2-propyl-2-enyloxyethanolamine with a yield of 41.5%. The sample was analyzed and the purity was 98.7%.

[0061] The gas chromatogram of N,N-dimethyl-2-propyl-2-enyloxyethanolamine obtained in Example 4 is as follows Figure 4 As shown, 1 HNMR images Figure 5 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 1L three-necked round-bottom flask equipped with a condenser, an electric stirrer and a constant pressure dropping funnel, and then 2.25 mol of solid KOH (148.5 g) was added. The mechanical stirring was turned on, and the three-necked round-bottom flask was placed in an oil bath and heated to 110°C for reaction for 3 h. Then, it was placed in an ice bath (0°C) for cooling. After 0.5 h, 2 mol of allyl bromide (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 stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (100 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (100 ml), and the washed aqueous phase was extracted 3 times with n-hexane (100 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was subjected to rotary evaporation to remove the solvent at a water temperature of 35°C and a pressure of 5KPa. The filtrate was distilled under reduced pressure (25Pa) with an oil pump, and the oil bath temperature was 60°C. The fractions at 36°C-40°C were collected to obtain 152.5 g of N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine with a yield of 41%. The purity was 95% after sampling and analysis.

[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, an electric stirrer and a constant pressure dropping funnel, and then 0.45 mol of solid KOH (29.8 g) was added. The mechanical stirring was turned on, and the three-necked round-bottom flask was placed in an oil bath and heated to 110°C for reaction for 3 h. Then, it was placed in an ice bath (0°C) for cooling. 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 stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (50 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (50 ml), and the washed aqueous phase was extracted 3 times with n-hexane (50 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was evaporated with a rotary evaporator at a water temperature of 35°C and a pressure of 5KPa to remove the solvent, and distilled under reduced pressure (25Pa) with an oil pump, the oil bath temperature was 60°C, and the fractions at 36°C-40°C were collected to obtain 29 g of N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine with a yield of 54.6%. Sampling and analysis showed a purity of 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, an electric stirrer and a constant pressure dropping funnel, and then 0.45 mol of solid KOH (30.1 g) was added. The mechanical stirring was turned on, and the three-necked round-bottom flask was placed in an oil bath and heated to 110°C for reaction for 3 h. Then, it was placed in an ice bath (0°C) for cooling. 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 stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (50 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (50 ml), and the washed aqueous phase was extracted 3 times with n-hexane (50 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was evaporated with a rotary evaporator at a water temperature of 35°C and a pressure of 5KPa to remove the solvent. The filtrate was distilled under reduced pressure (25Pa) with an oil pump, and the oil bath temperature was 60°C. The fractions at 36°C-40°C were collected to obtain 25.7 g of N,N-dimethyl-2-[2-(2-propylene-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 1L three-necked round-bottom flask equipped with a condenser, an electric stirrer and a constant pressure dropping funnel, and then 2.25 mol of solid sodium hydroxide (91.8 g) was added. The mechanical stirring was turned on, and the three-necked round-bottom flask was placed in an oil bath and heated to 110°C for reaction for 3 h. Then, it was placed in an ice bath (0°C) for cooling. 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 stopping the reaction, the reaction mixture was filtered under reduced pressure with a water pump to remove unreacted solid raw materials and solid by-products generated by the reaction. The filter residue was washed with n-hexane (100 ml), the filtrate and the n-hexane washing solution were combined, and the obtained organic solution containing the target product was washed twice with a saturated sodium bicarbonate solution (100 ml), and the washed aqueous phase was extracted 3 times with n-hexane (100 ml). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was subjected to rotary evaporation to remove the solvent at a water temperature of 35°C and a pressure of 5KPa. The filtrate was distilled under reduced pressure (25Pa) with an oil pump, and the oil bath temperature was 60°C. The fractions at 36°C-40°C were collected to obtain 95.2 g of N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine with a yield of 32.9%. The purity was 93.8% after sampling and analysis.

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

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

[0072] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for synthesizing N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine, characterized in that: The steps include: a) reacting 2-[2-(dimethylamino)ethoxy]ethanol with potassium hydroxide at a temperature of 80°C to 120°C for 2h to 6h; b) Cooling the reaction solution of step a) to -5°C to 5°C, then adding allyl chloride dropwise, maintaining the temperature at -5°C to 5°C for reaction for 1h to 4h, raising the temperature to 10°C to 35°C and reacting for another 8h to 30h.

2. The method for synthesizing N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine according to claim 1, characterized in that: The reaction temperature of step a) is 100°C to 110°C.

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

4. The method for synthesizing N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine according to claim 1, characterized in that: The reaction solution of step a) is cooled to -2°C to 2°C, and then allyl chloride is added dropwise, and the temperature is maintained at -2°C to 2°C for reaction for 2h to 3h, and then the temperature is raised to 20°C to 30°C for reaction for another 12h to 20h.

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

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 the 2-[2-(dimethylamino)ethoxy]ethanol, potassium hydroxide and allyl chloride is 1:(1.2-3):(1.1-2), and more preferably 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 claim 1, characterized in that: The reactions of step a) and step b) are both carried out under the protection of inert gas.

8. The method for synthesizing N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine according to any one of claims 1 to 7, characterized in that: The reaction mixture after the reaction in step b) is further subjected to the following post-treatment: (1) filtering the reaction mixture, washing the filter residue with an organic solvent, and collecting the filtrate and the washing liquid to obtain an organic solution containing the target product; (2) washing the organic solution containing the target product with alkaline water, drying it, and then concentrating it to obtain a concentrated solution; (3) The concentrated liquid is subjected to reduced pressure distillation, and the fraction at 36° C. to 40° C. is collected to obtain the N,N-dimethyl-2-[2-(2-propylene-1-yloxy)ethoxy]-ethylamine.

9. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 8, characterized in that: The organic solvent in step (1) is selected from one or more of n-hexane, cyclohexane, ethyl acetate and dichloromethane; And / or, the alkaline water 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 3KPa to 8KPa; And / or, the concentration temperature in step (2) is 30° C. to 40° C.; And / or, the pressure of the reduced pressure distillation in step (3) is 20Pa to 120Pa; And / or, the temperature of the reduced pressure distillation in step (3) is 40°C to 70°C.

10. The method for synthesizing N,N-dimethyl-2-[2-(2-propen-1-yloxy)ethoxy]-ethylamine according to claim 8, characterized in that: Step (2) comprises: 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, and concentrating to obtain a concentrated solution; The organic solvent used for extraction is preferably one or more of n-hexane, cyclohexane, ethyl acetate and dichloromethane.

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