A synthesis process of N,N-dimethylmorpholinium chloride

Abstract

The invention provides a synthesis technique of N, N-dimethylmorpholinium chloride, comprising the following steps: adding morpholine, solvent, and supported acid binding agent to a reactor, stirring, heating, passing chloromethane gas, and continuing to stir the reaction after passing through; after the reaction is completed, cooling, standing, filtering, performing vacuum distillation and concentration, crystallization, vacuum drying, and obtaining N, N-dimethylmorpholinium chloride. The synthesis process of the present invention has simple steps, low production cost, and a one-step method can generate the desired product, while using environmentally friendly solvents and auxiliary agents, raw materials can be recycled and reused, and economic benefits and environmental benefits are achieved. Coordinated development, and the yield and purity of N, N-dimethylmorpholinium chloride are high, with good application value.

Description

Technical Field

[0001] The invention belongs to the technical field of drug synthesis technology, and specifically relates to a synthesis process of N,N-dimethylmorpholinium chloride. Background Art

[0002] N,N-Dimethylmorpholinium chloride is an important organic compound, which is widely used in industrial production, especially in the fields of medicine, plant regulation, agriculture, pesticides, fragrances and synthetic materials. The research and development of its synthesis process is of great significance.

[0003] Traditional chemical synthesis processes are often accompanied by environmental pollution problems. Therefore, developing clean and environmentally friendly production methods is an important issue in the current chemical industry. The research on the synthesis process of N,N-dimethylmorpholinium chloride is based on this concept and aims to achieve low waste emissions.

[0004] The existing synthesis process of N,N-dimethylmorpholinium chloride involves multiple steps, which not only increases the production cost, but also may lead to lower overall yield and higher energy consumption; at the same time, a large amount of strong acid, strong base and organic solvent are required in the synthesis process. The use of these chemicals not only increases the complexity of the operation and safety risks, but also the waste acid and waste base generated in the reaction process are difficult to recycle and the treatment cost is high, posing a potential threat to the environment. While pursuing economic benefits, the existing synthesis process cannot meet the requirements of environmental protection, making it difficult to achieve coordinated development of economic and environmental benefits.

[0005] Chinese patent CN 102786495 B discloses a method for preparing N-methylmorpholine, comprising reacting dimethylamine with bis(2-haloethyl)ether at 30-100°C for 2-10h to obtain N,N-dimethylmorpholine quaternary ammonium salt and polyethylamine at 100-180°C for at least 3-12h. The method of the invention has mild reaction conditions and high product yield and purity. However, it requires two steps to generate N-methylmorpholine, and the reaction time is long. N,N-dimethylmorpholinium chloride is a derivative of N-methylmorpholine. Using this preparation method to continue the reaction to generate N,N-dimethylmorpholinium chloride will make the synthesis process more complicated, and the yield and purity of N,N-dimethylmorpholinium chloride will decrease.

[0006] Therefore, there is an urgent need for a synthesis process of N,N-dimethylmorpholinium chloride, which can not only simplify the synthesis steps and shorten the production process, but also adopt environmentally friendly solvents and additives, reduce or eliminate the use of harmful chemicals, and achieve a win-win situation in economic and environmental benefits. Summary of the invention

[0007] In view of the existing technical problems, the purpose of the present invention is to provide a synthesis process of N, N-dimethylmorpholinium chloride. The synthesis process of the present invention has simple steps, low production cost, and can generate the desired product in one step. At the same time, environmentally friendly solvents and additives are used, and the raw materials can be recycled and reused, achieving the coordinated development of economic benefits and environmental benefits. In addition, the yield and purity of N, N-dimethylmorpholinium chloride are high, and the application value is good.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides a synthesis process of N,N-dimethylmorpholinium chloride, comprising the following steps:

[0010] (1) adding morpholine, solvent and supported acid binding agent into a reaction kettle, stirring, heating, introducing methyl chloride gas, controlling the reaction temperature, and continuing to stir the reaction after the introduction is completed;

[0011] (2) After the reaction is completed, vacuum distillation is performed, cooling is performed, the mixture is allowed to stand and filtered, crystallized, vacuum dried, and crushed to obtain N,N-dimethylmorpholinium chloride.

[0012] Preferably, the synthesis process of N,N-dimethylmorpholinium chloride comprises the following steps:

[0013] (1) Add morpholine, solvent and supported acid binding agent into a reaction kettle, stir for 20-40 min, heat and introduce chloromethane gas, control the reaction temperature, and continue to stir and react for 1-2 h after the introduction is completed;

[0014] (2) After the reaction is completed, the solvent is distilled under reduced pressure until the remaining solvent is 5-10% of the total volume, cooled to 30-40° C., allowed to stand for 1-1.5 hours, and then the supported acid binding agent is filtered out, crystallized, vacuum dried, and crushed to obtain N,N-dimethylmorpholinium chloride.

[0015] The reaction mechanism and effects of the present invention are as follows:

[0016] 1. The present invention loads the acid-binding agent and the composite metal on the carbon nanotubes to promote the formation of N,N-dimethylmorpholinium chloride.

[0017] On the one hand, hydrogen chloride is generated when morpholine and methyl chloride react, and the acid binder can neutralize the hydrogen chloride generated in the system. Loading the acid binder on the carbon nanotubes can improve the dispersibility and contact area of ​​the acid binder, thereby improving the efficiency of neutralizing the acidic substance. At the same time, the applicant selects a specific sterically hindered acid binder to make the acid binder moderately nucleophilic, thereby avoiding side reactions with the electrophilic reagent methyl chloride in the reaction, thereby improving the selectivity of the reaction and the purity of the product. The steric hindrance may slow down the approach of other molecules to the reaction center, thereby regulating the rate of the chemical reaction, avoiding a sharp rise in temperature due to excessively fast reactions, further improving the chemical equilibrium constant, and increasing the yield of the product.

[0018] On the other hand, the surfaces of the cobalt and nickel metal components in the supported acid binding agent have unsaturated atomic orbitals, which can provide active sites, so that the reactant molecules can be adsorbed on the surface, thereby reducing the activation energy of the reaction, increasing the reaction rate and selectivity, promoting the smooth progress of the reaction, and pushing the reaction equilibrium to move in the direction of generating N,N-dimethylmorpholinium chloride; at the same time, cobalt and nickel can have a strong coordination effect with N in the morpholine structure to form a metastable intermediate. When the water molecules in the metastable intermediate are activated by the composite metal components, the water molecules will dissociate, and the dissociation process will absorb a part of the energy, which makes up for the problem of excessive heat release that may be caused by the increase in the reaction rate, and achieves the purpose of regulating the temperature of the reaction system.

[0019] In addition, as morpholine and methyl chloride react, the system temperature continues to rise. High temperature conditions will cause methyl chloride to decompose, which is not conducive to the improvement of the chemical equilibrium constant. Carbon nanotubes, due to their unique nanostructure and excellent physical properties, can effectively improve the heat exchange rate and heat dissipation efficiency, saving the energy consumption required for the internal circulation water cooling method and further improving the product yield.

[0020] Furthermore, the supported acid-binding agent is easier to separate and recycle after the reaction due to the stability of its carrier, which helps to reduce costs and environmental impact, and achieve coordinated development of economic and environmental benefits.

[0021] 2. The present invention strictly controls the reaction temperature to 30-50°C to avoid slow reaction rate leading to reduced yield, thereby increasing the chemical equilibrium constant. The applicant further increases the yield and purity of the reaction by controlling the mass ratio of morpholine, methyl chloride and supported acid binding agent.

[0022] 3. The present invention uses chloromethane as a raw material instead of formaldehyde and formic acid that may be used in traditional processes. Chloromethane is a high-purity gas and does not bring waste that does not participate in the reaction into the reaction system from the source, thus laying a raw material foundation for clean production.

[0023] 4. The present invention uses water instead of organic solvent as solvent, making the reaction process more green and environmentally friendly.

[0024] 5. The present invention uses a one-step method to synthesize N,N-dimethylmorpholinium chloride, which reduces the generation of intermediate products, saves energy consumption and raw material costs, simplifies the process, and reduces pollutant emissions.

[0025] In some embodiments, the mass ratio of morpholine, methyl chloride gas and supported acid binding agent in step (1) is (8-12):(5-7):1.

[0026] Preferably, the mass ratio of morpholine, methyl chloride gas and supported acid binding agent in step (1) is 10:6:1.

[0027] In some embodiments, the solvent in step (1) is deionized water.

[0028] In some embodiments, the heating temperature in step (1) is 30-50°C.

[0029] Preferably, the heating temperature in step (1) is 35-45°C.

[0030] In some embodiments, the duration of introducing chloroform in step (1) is 3-4 hours.

[0031] In some embodiments, the reaction temperature in step (1) needs to be controlled not to exceed 80°C. Furthermore, if the reaction temperature is too high, an internal circulating water cooling method is used to keep the reaction temperature below 80°C.

[0032] Preferably, in step (1), the reaction temperature needs to be controlled not to exceed 60°C. Furthermore, if the reaction temperature is too high, internal circulating water cooling is used to keep the reaction temperature below 60°C.

[0033] In some embodiments, the method for preparing the supported acid binding agent in step (1) comprises the following steps:

[0034] S1. The acidified carbon nanotubes were added to deionized water for ultrasonic dispersion to obtain a carbon nanotube dispersion for later use; cobalt acetate tetrahydrate, nickel acetate tetrahydrate, and deionized water were added to a container and stirred to obtain a composite metal solution for later use;

[0035] S2. Add the carbon nanotube dispersion and the composite metal solution obtained in step S1 to a reaction kettle, add an acid-base regulator, stir, then add triethylamine, stir, and then perform a hydrothermal reaction, separate, wash, and dry the obtained precipitate 1 to obtain a metal-loaded carbon nanotube material;

[0036] S3. Stir the metal-supported carbon nanotube material and deionized water obtained in step S2, add an acid-binding agent, and then perform a hydrothermal reaction. Separate, wash, and dry the obtained precipitate 2 to obtain a supported acid-binding agent.

[0037] Preferably, the method for preparing the supported acid binding agent in step (1) comprises the following steps:

[0038] S1. The acidified carbon nanotubes were added to deionized water for ultrasonic dispersion for 5-15 min to obtain a carbon nanotube dispersion for later use; cobalt acetate tetrahydrate, nickel acetate tetrahydrate and deionized water were added to a container and stirred for 20-30 min to obtain a composite metal solution for later use;

[0039] S2. Add the carbon nanotube dispersion and composite metal solution obtained in step S1 to a reaction kettle, add an acid-base regulator, stir for 5-15 minutes, then add triethylamine, stir for 20-40 minutes, and then perform a hydrothermal reaction at 120-160° C. for 10-12 hours, separate, wash and dry the obtained precipitate 1 to obtain a metal-loaded carbon nanotube material;

[0040] S3. Stir the metal-supported carbon nanotube material and deionized water obtained in step S2 for 5-15 minutes, add an acid binding agent, and then perform a hydrothermal reaction at 140-160° C. for 5-6.5 hours. Separate, wash and dry the obtained precipitate 2 to obtain a supported acid binding agent.

[0041] In some embodiments, the mass ratio of the acidified carbon nanotubes, cobalt acetate tetrahydrate and nickel acetate tetrahydrate in step S1 is 1:(4-8):(4-6).

[0042] Preferably, the mass ratio of cobalt acetate tetrahydrate to nickel acetate tetrahydrate in step S1 is (1-2):1.

[0043] Further preferably, in step S1, the mass ratio of the acidified carbon nanotubes, cobalt acetate tetrahydrate and nickel acetate tetrahydrate is 1:7.2:4.8.

[0044] In some embodiments, the mass ratio of the metal-supported carbon nanotube material to the acid-binding agent in step S3 is 1:(1.5-2.5).

[0045] Specifically, the preparation steps of the acidified carbon nanotubes in step S1 are: treating the carbon nanotubes with an acid, washing, and drying to obtain the acidified carbon nanotubes.

[0046] Specifically, the acid-base regulator in step S2 is any one or more of sodium carbonate, sodium bicarbonate and sodium citrate.

[0047] Specifically, the acid binding agent in step S3 is at least one of 5-ethyl-2-methylpyridine, 4-methylpyridine and N,N-dimethylaniline.

[0048] Specifically, the crystallization in step (2) can be carried out by natural crystallization or crystallization by adding acetone solvent.

[0049] More preferably, the crystallization in step (2) is carried out by natural crystallization.

[0050] In some embodiments, the yield of the N,N-dimethylmorpholinium chloride is not less than 97%, and the purity is not less than 96%.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. The synthesis process of the present invention has simple steps, low production cost, and can generate the desired product in one step. Environmentally friendly solvents and additives are used, and the raw materials can be recycled and reused, thereby achieving the coordinated development of economic benefits and environmental benefits. In addition, the yield and purity of N,N-dimethylmorpholinium chloride are high, and the product has good application value.

[0053] 2. The present invention loads the acid-binding agent and the composite metal on the carbon nanotubes to promote the formation of N,N-dimethylmorpholinium chloride. The loaded acid-binding agent is easier to separate and recover after the reaction due to the stability of its carrier, which helps to reduce costs and environmental impact, and achieves coordinated development of economic benefits and environmental benefits.

[0054] 3. The present invention uses a supported acid binding agent. On the one hand, the acid binding agent is loaded on carbon nanotubes, which can improve the dispersibility and contact area of ​​the acid binding agent, thereby improving the efficiency of neutralizing acidic substances; at the same time, the applicant selects an acid binding agent with suitable steric hindrance, which can effectively improve the product purity and yield. On the other hand, the cobalt and nickel metal components in the supported acid binding agent are conducive to improving the rate and selectivity of the reaction, and promote the reaction equilibrium to move in the direction of generating N, N-dimethylmorpholinium chloride. In addition, carbon nanotubes can effectively improve the heat exchange rate and heat dissipation efficiency, saving the energy consumption required for adopting the internal circulation water cooling method.

[0055] 4. The present invention strictly controls the reaction temperature to 30-50°C to avoid slow reaction rate leading to reduced yield, thereby increasing the chemical equilibrium constant. The applicant further increases the yield and purity of the reaction by controlling the mass ratio of morpholine, methyl chloride and supported acid binding agent.

[0056] 5. The present invention uses methyl chloride and water as raw materials, making the reaction process more green and environmentally friendly, laying a raw material foundation for clean production.

[0057] 6. The yield of N,N-dimethylmorpholinium chloride of the present invention is not less than 97%, and the purity is not less than 96%. DETAILED DESCRIPTION

[0058] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, rather than to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0059] According to the ratios of the raw materials and the preparation methods specified in the following examples and comparative examples, N,N-dimethylmorpholinium chloride was synthesized.

[0060] In order to facilitate those skilled in the art to implement the present invention, the sources of some raw materials in the embodiments and comparative examples are described as follows:

[0061] The steps for preparing acidified carbon nanotubes are as follows:

[0062] 20 g of carbon nanotubes, 0.5 L of 68 wt% concentrated nitric acid and 1.5 L of 98 wt% concentrated sulfuric acid were treated with acid, refluxed and heated in an oil bath at 100° C. for 1 h for acidification, repeatedly filtered and rinsed with deionized water until neutral, and dried at 105° C. for 3 h to obtain acidified carbon nanotubes; wherein the carbon nanotubes were purchased from Shanghai Lishuo Composite Materials Technology Co., Ltd.

[0063] Other raw materials are not specially specified and can be purchased from the market.

[0064] Preparation Example 1

[0065] The preparation method of the supported acid binding agent A comprises the following steps:

[0066] S1. 5 g of acidified carbon nanotubes and 10 ml of deionized water were ultrasonically dispersed for 10 min to obtain a carbon nanotube dispersion for later use; 36 g of cobalt acetate tetrahydrate, 24 g of nickel acetate tetrahydrate and 250 ml of deionized water were added to a container and stirred for 30 min to obtain a composite metal solution for later use;

[0067] S2. Add the carbon nanotube dispersion and composite metal solution obtained in step S1 to a reactor, add 7.5 g of sodium carbonate, stir for 8 min, then add 0.25 ml of triethylamine, stir for 30 min, and then perform a hydrothermal reaction at 140 ° C for 12 h, separate the precipitate 1, wash it with deionized water 3 times, and dry it at 105 ° C for 4 h to obtain a metal-loaded carbon nanotube material;

[0068] S3. 8 g of the metal-supported carbon nanotube material obtained in step S2 and 10 ml of deionized water were stirred for 10 min, 12 g of 5-ethyl-2-methylpyridine and 600 ml of deionized water were added, heated to 40 ° C, stirred for 20 min, and then subjected to hydrothermal reaction at 160 ° C for 6 h. The precipitate 2 was separated, washed with deionized water 3 times, and dried at 105 ° C for 6 h to obtain a supported acid binding agent A.

[0069] Preparation Example 2

[0070] The preparation method of the supported acid binding agent B comprises the following steps:

[0071] S1. 5 g of acidified carbon nanotubes and 10 ml of deionized water were ultrasonically dispersed for 10 min to obtain a carbon nanotube dispersion for later use; 10 g of cobalt acetate tetrahydrate, 10 g of nickel acetate tetrahydrate and 80 ml of deionized water were added to a container and stirred for 30 min to obtain a composite metal solution for later use;

[0072] S2. Add the carbon nanotube dispersion and composite metal solution obtained in step S1 to a reactor, add 7.5 g of sodium carbonate, stir for 8 min, then add 0.2 ml of triethylamine, stir for 30 min, and then perform a hydrothermal reaction at 140° C. for 12 h, separate the precipitate 1, wash it with deionized water 3 times, and dry it at 105° C. for 4 h to obtain a metal-loaded carbon nanotube material;

[0073] S3. 8 g of the metal-supported carbon nanotube material obtained in step S2 and 10 ml of deionized water were stirred for 10 min, 12 g of 5-ethyl-2-methylpyridine and 600 ml of deionized water were added, heated to 40 ° C, stirred for 20 min, and then subjected to hydrothermal reaction at 160 ° C for 6 h. The precipitate 2 was separated, washed with deionized water 3 times, and dried at 105 ° C for 6 h to obtain a supported acid binding agent B.

[0074] Preparation Example 3

[0075] The preparation method of the supported acid binding agent C comprises the following steps:

[0076] S1. 5 g of acidified carbon nanotubes and 10 ml of deionized water were ultrasonically dispersed for 10 min to obtain a carbon nanotube dispersion for later use; 36 g of cobalt acetate tetrahydrate, 24 g of nickel acetate tetrahydrate and 250 ml of deionized water were added to a container and stirred for 30 min to obtain a composite metal solution for later use;

[0077] S2. Add the carbon nanotube dispersion and composite metal solution obtained in step S1 to a reactor, add 7.5 g of sodium carbonate, stir for 8 min, then add 0.25 ml of triethylamine, stir for 30 min, and then perform a hydrothermal reaction at 140 ° C for 12 h, separate the precipitate 1, wash it with deionized water 3 times, and dry it at 105 ° C for 4 h to obtain a metal-loaded carbon nanotube material;

[0078] S3. 8 g of the metal-supported carbon nanotube material obtained in step S2 and 12 ml of deionized water were stirred for 10 min, 6 g of 5-ethyl-2-methylpyridine and 400 ml of deionized water were added, heated to 40° C., stirred for 20 min, and then subjected to hydrothermal reaction at 160° C. for 6 h. The precipitate 2 was separated, washed with deionized water 3 times, and dried at 105° C. for 6 h to obtain a supported acid binding agent C.

[0079] Preparation Example 4

[0080] The preparation method of supported acid binding agent D is the same as that of Preparation Example 1, except that an equal amount of sodium hydroxide is used to replace 5-ethyl-2-methylpyridine.

[0081] Example 1

[0082] A synthesis process of N,N-dimethylmorpholinium chloride comprises the following steps:

[0083] (1) Add 60 g of morpholine, 40 g of deionized water, and 6 g of a supported acid-binding agent into a reaction kettle, stir for 30 min, heat to 40° C., introduce 36 g of methyl chloride gas, and control the reaction temperature not to exceed 60° C. After the introduction, continue stirring and reacting for 1.5 h;

[0084] (2) After the reaction is completed, the mixture is distilled under reduced pressure until the remaining volume of deionized water is 8%, cooled to 35° C., allowed to stand for 1.5 h, and then the supported acid-binding agent A is filtered out, naturally crystallized, vacuum dried at 105° C. for 4 h, and crushed to obtain N,N-dimethylmorpholinium chloride.

[0085] Example 2

[0086] A synthesis process of N,N-dimethylmorpholinium chloride comprises the following steps:

[0087] (1) 48 g of morpholine, 32 g of deionized water, and 6 g of a supported acid-binding agent were added to a reaction kettle, stirred for 20 min, heated to 30° C., and introduced 30 g of methyl chloride gas, with the reaction temperature being controlled not to exceed 60° C. After the introduction, the reaction was continued with stirring for 1 h;

[0088] (2) After the reaction is completed, the mixture is distilled under reduced pressure until the remaining volume of deionized water is 10%, cooled to 30° C., allowed to stand for 1 hour, and then the supported acid-binding agent A is filtered out, naturally crystallized, vacuum dried at 105° C. for 4 hours, and crushed to obtain N,N-dimethylmorpholinium chloride.

[0089] Example 3

[0090] A synthesis process of N,N-dimethylmorpholinium chloride comprises the following steps:

[0091] (1) 72 g of morpholine, 48 g of deionized water, and 6 g of a supported acid-binding agent were added to a reaction kettle, stirred for 40 min, heated to 50° C., and introduced 42 g of methyl chloride gas, with the reaction temperature being controlled not to exceed 60° C. After the introduction, the reaction was continued to stir for 2 h;

[0092] (2) After the reaction is completed, the mixture is distilled under reduced pressure until the remaining volume of deionized water is 5%, cooled to 40° C., allowed to stand for 1.5 h, and then the supported acid-binding agent A is filtered out, naturally crystallized, vacuum dried at 105° C. for 4 h, and crushed to obtain N,N-dimethylmorpholinium chloride.

[0093] Example 4

[0094] A synthesis process of N,N-dimethylmorpholinium chloride, the specific implementation method is the same as that of Example 1, except that an equal amount of supported acid binding agent B is used to replace supported acid binding agent A.

[0095] Example 5

[0096] A synthesis process of N,N-dimethylmorpholinium chloride, the specific implementation method is the same as that of Example 1, except that an equal amount of supported acid binding agent C is used to replace supported acid binding agent A.

[0097] Example 6

[0098] A synthesis process of N,N-dimethylmorpholinium chloride, the specific implementation method is the same as that of Example 1, except that an equal amount of supported acid binding agent D is used to replace supported acid binding agent A.

[0099] Example 7

[0100] A synthesis process of N,N-dimethylmorpholinium chloride comprises the following steps:

[0101] (1) 30 g of morpholine, 20 g of deionized water, and 6 g of a supported acid-binding agent were added to a reaction kettle, stirred for 30 min, heated to 40° C., and introduced 30 g of methyl chloride gas, with the reaction temperature being controlled not to exceed 60° C. After the introduction, the reaction was continued with stirring for 1.5 h;

[0102] (2) After the reaction is completed, the mixture is distilled under reduced pressure until the remaining volume of deionized water is 5%, cooled to 40° C., allowed to stand for 1.5 h, and then the supported acid-binding agent A is filtered out, naturally crystallized, vacuum dried at 105° C. for 4 h, and crushed to obtain N,N-dimethylmorpholinium chloride.

[0103] Example 8

[0104] A synthesis process of N,N-dimethylmorpholinium chloride comprises the following steps:

[0105] (1) Add 60 g of morpholine, 40 g of deionized water, and 6 g of a supported acid-binding agent into a reaction kettle, stir for 30 min, heat to 60 ° C, introduce 36 g of methyl chloride gas, and control the reaction temperature not to exceed 90 ° C. After the introduction is completed, continue to stir and react for 1.5 h;

[0106] (2) After the reaction is completed, the mixture is distilled under reduced pressure until the remaining volume of deionized water is 5%, cooled to 40° C., allowed to stand for 1.5 h, and then the supported acid-binding agent A is filtered out, naturally crystallized, vacuum dried at 105° C. for 4 h, and crushed to obtain N,N-dimethylmorpholinium chloride.

[0107] Comparative Example 1

[0108] A synthesis process of N,N-dimethylmorpholinium chloride, the specific implementation method is the same as that of Example 1, except that an equal amount of triethylamine is used to replace the supported acid binding agent A.

[0109] Effect evaluation:

[0110] The N,N-dimethylmorpholinium chloride synthesized in the above Examples 1-8 and Comparative Example 1 was tested, and the content of the product was determined using a gas chromatograph. The specific results are shown in Table 1.

[0111] Table 1

[0112] Serial number Yield / % purity / % Example 1 98.0 98.5 Example 2 97.0 97.6 Example 3 97.5 98.0 Example 4 95.9 96.4 Example 5 94.2 95.1 Example 6 90.7 93.7 Example 7 89.3 92.3 Example 8 88.0 90.1 Comparative Example 1 83.7 86.3

[0113] From the results in Table 1, it can be seen that the yield and purity of the N,N-dimethylmorpholinium chloride prepared in Examples 1-3 are better and have better application value.

[0114] Compared with Example 1, when preparing the supported acid binding agent, the mass ratio of the acidified carbon nanotubes, cobalt acetate tetrahydrate and nickel acetate tetrahydrate in step S1 was changed, which could not well promote the reaction equilibrium to move towards the direction of generating N,N-dimethylmorpholinium chloride, resulting in reduced yield and purity.

[0115] Compared with Example 1, when preparing the supported acid binding agent, the mass ratio of the metal-supported carbon nanotube material and the acid binding agent in step S3 was changed, which could not neutralize hydrogen chloride better and would decompose methyl chloride, thereby affecting the yield and purity.

[0116] Compared with Example 1, when preparing the supported acid binding agent, an equal amount of sodium hydroxide was used to replace 5-ethyl-2-methylpyridine. The alkalinity was too strong and the steric hindrance was very small, which would decompose methyl chloride and affect the reaction rate, thereby affecting the yield and purity.

[0117] In Example 7, compared with Example 1, the mass ratio of morpholine, methyl chloride and supported acid binding agent was changed. Inappropriate addition of raw materials would reduce the yield and purity of N,N-dimethylmorpholinium chloride.

[0118] Compared with Example 1, the reaction temperature in Example 8 is higher than 50°C, and the temperature is controlled not to exceed 90°C. Too high a temperature will decompose methyl chloride, thereby affecting the yield and purity.

[0119] Comparative Example 1 Compared with Example 1, replacing the supported acid binding agent A with an equal amount of the acid binding agent triethylamine not only reduces the efficiency of neutralizing the acidic substance, but also affects the reaction rate, thereby affecting the yield and purity.

[0120] The above is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present application. Although the present application is disclosed as above in the preferred embodiment, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution.

Claims

1. A process for synthesizing N,N-dimethylmorpholinium chloride, characterized in that: The following steps are included: (1) adding morpholine, solvent and supported acid binding agent into a reaction kettle, stirring, heating, introducing methyl chloride gas, controlling the reaction temperature, and continuing to stir the reaction after the introduction is completed; (2) After the reaction is completed, cooling, standing, filtering, vacuum distillation and concentration, crystallization, vacuum drying, and crushing to obtain N,N-dimethylmorpholinium chloride; Wherein, the mass ratio of morpholine, methyl chloride gas and supported acid binding agent in step (1) is (8-12): (5-7): 1; the heating temperature is 30-50°C; The method for preparing the supported acid binding agent in step (1) comprises the following steps: S1. The acidified carbon nanotubes were added to deionized water for ultrasonic dispersion to obtain a carbon nanotube dispersion for later use; cobalt acetate tetrahydrate, nickel acetate tetrahydrate, and deionized water were added to a container and stirred to obtain a composite metal solution for later use; S2. The carbon nanotube dispersion and the composite metal solution obtained in step S1 are added to a reaction vessel, an acid-base regulator is added, stirred, and then triethylamine is added, stirred, and then subjected to a hydrothermal reaction, and the obtained precipitate 1 is separated, washed, and dried to obtain a metal-loaded carbon nanotube material; S3. The metal-supported carbon nanotube material obtained in step S2, deionized water, stirred, an acid binding agent was added, and then subjected to a hydrothermal reaction, and the obtained precipitate 2 was separated, washed, and dried to obtain a supported acid binding agent; The mass ratio of the acidified carbon nanotubes, cobalt acetate tetrahydrate and nickel acetate tetrahydrate in step S1 is 1:(4-8):(4-6); the mass ratio of the metal-supported carbon nanotube material and the acid binding agent in step S3 is 1:(1.5-2.5); the acid binding agent in step S3 is 5-ethyl-2-methylpyridine.

2. The synthesis process of N,N-dimethylmorpholinium chloride according to claim 1, characterized in that: The solvent in step (1) is deionized water.

3. The synthesis process of N,N-dimethylmorpholinium chloride according to claim 1, characterized in that: The duration of introducing chloroform in step (1) is 3-4 hours.

4. The synthesis process of N,N-dimethylmorpholinium chloride according to claim 1, characterized in that: The reaction temperature in step (1) is controlled not to exceed 80°C.

5. The synthesis process of N,N-dimethylmorpholinium chloride according to claim 1, characterized in that: The yield of the N,N-dimethylmorpholinium chloride is not less than 96%, and the purity is not less than 97%.