Brominated N-methylmorpholine N-oxide ionic liquid and preparation method thereof
The preparation of N-methylmorpholine N-oxide ionic liquid brominated by vacuum catalysis and vacuum oxidation methods solves the problems of slow speed, large energy consumption and complex process during cellulose dissolution, and achieves a more efficient cellulose dissolution and simplified process flow.
Patent Information
- Application Number
- CN202411914410.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-04-01
AI Technical Summary
The existing N-methylmorpholine N-oxide (NMMO) is slow in cellulose dissolution, has a large energy consumption, and is complex in recycling and recycling processes, which limits its wide range of applications.
N-methylmorpholine brominated is prepared by vacuum catalysis, and N-methylmorpholine brominated is prepared by vacuum oxidation to form a new ionic liquid with the advantages of higher yield, strong ionic polarity, gentle preparation conditions, short reaction flow and high efficiency.
It significantly improves the cellulose dissolution rate, reduces energy consumption, simplifies the recycling and recycling process, and increases the dissolution time, so that the ionic liquid has a wider application prospect in the fields of organic chemical reactions, separation technology and electrochemistry.
Smart Images
Figure CN119735566A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of ionic liquid synthesis, in particular to a brominated N-methylmorpholine N-oxide ionic liquid and a preparation method thereof. Background Art
[0002] In recent years, N-methylmorpholine N-oxide (NMMO), as an alicyclic tertiary amine oxide, has been widely used in pesticides, herbicides, metal rust inhibitors, organic synthesis, and especially as a solvent for regenerated cellulose Lyocell fibers, laying the foundation for the preparation of green and environmentally friendly regenerated cellulose. However, the slow dissolution rate of cellulose, high energy consumption, and complex recycling process have restricted its wide application.
[0003] With the goal of developing a new fiber dissolution and preparation process, our team synthesized N-methylmorpholine bromide N-oxide ([NMMO] + Br - ), forming an ionic liquid based on N-methylmorpholine N-oxide (NMMO), which is a new type of ionic liquid material. It has a higher boiling point, almost no vapor pressure, high thermal and chemical stability, and strong solubility, and is expected to become a better environmentally friendly green solvent. Its unique physical and chemical properties are expected to be widely used in organic chemical reactions, separation technology and electrochemical fields, such as catalysts, separation agents, etc. Summary of the invention
[0004] The present application provides an N-methylmorpholine N-oxide ionic liquid and a preparation method thereof. The brominated N-methylmorpholine N-oxide ([NMMO] + Br - ) ionic liquid has the advantages of high yield, strong ion polarity, mild preparation conditions, short reaction process and high efficiency.
[0005] The present application provides a method for preparing N-methylmorpholine bromide N-oxide ionic liquid, comprising the following steps in sequence: preparing N-methylmorpholine bromide by vacuum catalysis and preparing N-methylmorpholine bromide N-oxide by vacuum oxidation; the vacuum catalytic preparation of N-methylmorpholine bromide comprises the following steps: S1, stirring and mixing a certain mass of N-methylmorpholine, a bromination catalyst and deionized water under vacuum to obtain a mixed A liquid; S2, heating the mixed A liquid to a certain temperature, adding a certain amount of bromination reactant during stirring, and cooling and filtering to obtain a brominated N-methylmorpholine ionic liquid; the vacuum oxidation preparation of N-methylmorpholine bromide N-oxide comprises the following steps: S3, mixing a certain mass of the N-methylmorpholine bromide ionic liquid, an oxidation catalyst and deionized water under vacuum to obtain a mixed B liquid; S4, heating the mixed B liquid to a certain temperature, adding a certain amount of oxidation reactant, maintaining the temperature at a certain temperature and controlling the reaction time to the reaction end point, filtering to remove the catalyst, and distilling under reduced pressure to obtain an ionic liquid of N-methylmorpholine bromide N-oxide.
[0006] Preferably, in the S1 reaction step, the bromination catalyst is ferric tribromide.
[0007] Preferably, in the S2 reaction step, the bromination reactant is one or both of bromine and hydrogen bromide.
[0008] Preferably, in the S3 reaction step, the oxidation catalyst is nano copper oxide.
[0009] Preferably, in the S4 reaction step, the oxidation reactant is hydrogen peroxide.
[0010] Preferably, the preparation method of brominated N-methylmorpholine N-oxide ionic liquid in the present application also includes a preparation method of N-methylmorpholine N-oxide ionic liquid with a low degree of bromination, a preparation method of N-methylmorpholine N-oxide ionic liquid with a medium degree of bromination, and a preparation method of N-methylmorpholine N-oxide ionic liquid with a high degree of bromination.
[0011] Preferably, in the method for preparing N-methylmorpholine N-oxide ionic liquid with a bromination degree of (8-30%) (the percentage of the ratio of the molar number of Br in the product to the molar number of NMM and NMMO), the weight ratio of the N-methylmorpholine, the catalyst, the bromination reactant and the deionized water is (45.0-65.0):(0.1-0.3):(8.0-12.0):(22.7-46.9); and the bromination reactant is bromine.
[0012] Preferably, in the method for preparing the N-methylmorpholine N-oxide ionic liquid with a moderate (30-60%) degree of bromination, the weight ratio of the N-methylmorpholine, the catalyst, the bromination reactant and the deionized water is (35.1-45.2):(2.5-3):(10.8-16.8):(35.0-51.6); the bromination reactant is hydrogen bromide.
[0013] Preferably, in the method for preparing the N-methylmorpholine N-oxide ionic liquid with a high degree of bromination (60-90), the weight ratio of the N-methylmorpholine, the catalyst, the bromination reactant and the deionized water is (15.8-32.2):(4.0-8.0):(18.5-33.2):(26.6-61.7); the bromination reactant is a mixture of bromine and hydrogen bromide in a weight ratio of 1:1.
[0014] On the other hand, the present application discloses a brominated N-methylmorpholine N-oxide ionic liquid, which is prepared by adopting the preparation method of the brominated N-methylmorpholine N-oxide ionic liquid.
[0015] One or more technical solutions provided in this application have at least the following technical effects or advantages:
[0016] 1. The present invention provides N-methylmorpholine bromide N-oxide ([NMMO] + Br - ), the content of which is 50-60%, [NMMO] + Br - The yield is 95-99%.
[0017] 2. The present invention provides N-methylmorpholine bromide N-oxide ([NMMO]+Br-), which is a colorless to pale yellow liquid. It remains unchanged for more than one year at room temperature and has good stability.
[0018] 3. Through the comparison of this application NMMO, [NMMO] + Br - Used for dissolving cellulose pulp (molecular weight DP: 5.4-5.8 million). When the water content is 17.5% and the fiber weight is the same as the ionic liquid weight, the NMMO is completely dissolved in 6 hours under the conditions of heating to 80°C and 1200 rpm strong stirring. [NMMO] + Br - The dissolution time is 1-2 hours, which can significantly reduce the dissolution time. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0020] Figure 1 This is a flow chart for the synthesis and preparation of methylmorpholine bromide oxide ion liquid in this application;
[0021] Figure 2 This is the H NMR spectrum analysis diagram of different bromination degrees of Examples 1-3 in this application;
[0022] Figure 3 This is the appearance of the ionic liquids with different degrees of bromination in Examples 1-3 of this application. DETAILED DESCRIPTION
[0023] The present application provides an N-methylmorpholine N-oxide ionic liquid and a preparation method thereof. The brominated N-methylmorpholine N-oxide ([NMMO] + Br - ) ionic liquid has the advantages of high yield, strong ion polarity, mild preparation conditions, short reaction process and high efficiency.
[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products, or devices.
[0026] raw material
[0027] N-Methylmorpholine CAS No.: 109-02-4 Molecular weight: 101.147 Purity 99.0%;
[0028] Ferrous bromide CAS number: 7727-15-3 Molecular weight: 266.694 Purity 99.0%;
[0029] Bromine CAS number: 7726-95-6 Molecular weight: 159.808 Purity 99.0%;
[0030] Hydrogen bromide CAS number: 10035-10-6 Molecular weight: 80.912 Purity 48.0%;
[0031] Nano copper oxide CAS number: 1317-38-0 Molecular weight: 79.545 Purity 99.0%;
[0032] Hydrogen peroxide CAS number: 7722-84-1 Molecular weight: 34.015 Purity 30.0%.
[0033] Reference Figure 1 The technical scheme adopted in this application includes the synthesis of N-methylmorpholine bromide by vacuum catalytic substitution method and the preparation of N-methylmorpholine bromide N-oxide by vacuum oxidation method. Figure 1 The invention provides the synthesis and preparation mechanism and process of methylmorpholine bromide and methylmorpholine bromide oxide ionic liquid.
[0034] Example
[0035] Example 1
[0036] 10% bromide [NMMO] + Br - preparation
[0037] S1. According to the weight ratio, 64.6 parts of N-methylmorpholine, 0.1 parts of ferric bromide (catalyst), and 25.3 parts of deionized water were reacted in a vacuum reactor, wherein the vacuum degree of the vacuum reactor was 0.09 MPa, and stirred at a speed of 1000 for 0.5 hours to obtain a mixed liquid A.
[0038] S2, the mixed liquid A was heated to 60°C, and 10 parts by weight of bromine was added dropwise at 800 rpm for 1 hour, and after the reaction was completed, the mixture was filtered and cooled to obtain N-methylmorpholine bromide ([NMM] + Br - ) ionic liquid.
[0039] S3. Add N-methylmorpholine bromide [NMM] into a vacuum reactor equipped with a condenser, thermometer, metering dropping funnel and stirring device. + Br -and a catalyst nano copper oxide dispersion, wherein the weight ratio is 30 parts of N-methylmorpholine bromide ion liquid, 0.5 parts of nano copper oxide dispersion (40-60nm weight percentage 10-20%) and 49.5 parts of deionized water; the vacuum degree of the vacuum reactor is controlled to be 0.08MPa, and it is stirred evenly to obtain a mixed liquid B;
[0040] S4. Heat the mixed solution B to 60°C, slowly drop 20 parts by weight of hydrogen peroxide (30%) into the mixture within 2 hours, raise the temperature to 60°C after the dropwise addition is completed, maintain this temperature for 2 hours until the end of the reaction, filter out the catalyst, and obtain [NMMO] by vacuum distillation. + Br - Ionic liquid.
[0041] The N-methylmorpholine bromide N-oxide ([NMMO] + Br - ), its content is 50%, the degree of bromination is 10%, [NMMO] + Br - The yield is 95.5%. Its appearance is a nearly colorless liquid. It has no change for more than one year at room temperature and has good stability. It is used to dissolve cellulose pulp (DP: 5.4-5.8 million). When the water content is 17.5%, the solution is heated to 80°C and stirred at 1200 rpm, and the dissolution time is 2 hours.
[0042] Example 2
[0043] S1. According to the weight ratio, 40 parts of N-methylmorpholine (98%), 2.8 parts of ferric bromide (catalyst) and 42.2 parts of deionized water are reacted in a vacuum reactor, wherein the vacuum degree of the vacuum reactor is 0.085 MPa, and stirred at 1500 rotation speed for 45 minutes to obtain a mixed liquid A.
[0044] S2, the mixed liquid A was heated to 70°C, and a mixture of 15 parts by weight of bromine and hydrogen bromide was added dropwise under stirring at 2000 rpm for 1.5 hours, and after the reaction was completed, the mixture was filtered and cooled to obtain N-methylmorpholine bromide ([NMM] + Br - ) ionic liquid.
[0045] S3. Add N-methylmorpholine bromide [NMM] into a vacuum reactor equipped with a condenser, thermometer, metering dropping funnel and stirring device. + Br -and a catalyst nano copper oxide dispersion, wherein the weight ratio is 40 parts of N-methylmorpholine bromide ion liquid, 1.3 parts of nano copper oxide dispersion (40-60nm weight percentage 10-20%) and 26.2 parts of deionized water; the vacuum degree of the vacuum reactor is controlled to be 0.08MPa, and it is stirred evenly to obtain a mixed liquid B;
[0046] S4. Heat the mixed solution B to 63°C, slowly drop 20 parts by weight of hydrogen peroxide (30%) into the mixture within 2.5 hours, raise the temperature to 60°C after the dropwise addition is complete, maintain this temperature for 2.5 hours until the end of the reaction, filter out the catalyst, and obtain [NMMO] by vacuum distillation. + Br - Ionic liquid.
[0047] Example 2 Preparation of N-methylmorpholine bromide N-oxide ([NMMO] + Br - ), its content is 55%, the degree of bromination is about 50%, [NMMO] + Br - The yield is 97%. Its appearance is a slightly yellowish colorless liquid. It has no change for more than one year at room temperature and has good stability. It is used to dissolve cellulose pulp (DP: 5.4-5.8 million). Under the conditions of 17.5% water content, heating to 80°C and strong stirring at 1200 rpm, the dissolution time is 1 hour and 45 minutes.
[0048] Example 3
[0049] S1. According to the weight ratio, 30 parts of N-methylmorpholine (98%), 6.0 parts of ferric bromide (catalyst) and 44.0 parts of deionized water were reacted in a vacuum reactor, wherein the vacuum degree of the vacuum reactor was 0.08 MPa, and stirred at a rotation speed of 2000 for 1 hour to obtain a mixed liquid A.
[0050] S2, the mixed liquid A was heated to 80°C, and a mixture of 20 parts by weight of bromine and hydrogen bromide (weight ratio 1:1) was added dropwise at 3000 rpm for 2 hours, and after the reaction was completed, the mixture was filtered and cooled to obtain N-methylmorpholine bromide ([NMM] + Br - ) ionic liquid.
[0051] S3. Add N-methylmorpholine bromide [NMM] into a vacuum reactor equipped with a condenser, thermometer, metering dropping funnel and stirring device. + Br -and a catalyst nano copper oxide dispersion liquid, wherein the weight ratio is 52 parts of N-methylmorpholine bromide ionic liquid, 2.0 parts of nano copper oxide dispersion liquid (40-60nm weight percentage 10-20%) and 1.0 parts of deionized water; the vacuum degree of the vacuum reactor is controlled to be 0.08MPa, and it is stirred evenly to obtain a mixed liquid B;
[0052] S4. Heat the mixed solution B to 65°C, slowly drop 45 parts by weight of hydrogen peroxide (30%) into the mixture within 3 hours, raise the temperature to 80°C after the dropwise addition is completed, maintain this temperature for 3 hours until the end of the reaction, filter out the catalyst, and obtain [NMMO] by vacuum distillation. + Br - Ionic liquid.
[0053] Example 3 Preparation of N-methylmorpholine bromide N-oxide ([NMMO] + Br - ), its content is 60%, the degree of bromination is about 80%, [NMMO] + Br - The yield is 96%. Its appearance is a light yellow liquid. It has no change for more than one year at room temperature and has good stability. It is used to dissolve cellulose pulp (DP: 5.4-5.8 million). When the water content is 17.5%, the solution is heated to 80°C and stirred at 1200 rpm, and the dissolution time is 1.5 hours.
[0054] Comparative Example
[0055] Comparative Example 1
[0056] The difference between Comparative Example 1 and Example 1 is that in step S1, no vacuum reactor is used, and N-methylmorpholine (98%), ferric bromide (catalyst) and deionized water are catalytically replaced in a normal pressure environment.
[0057] Comparative Example 2
[0058] The difference between Comparative Example 2 and Example 1 is that in step S3, no vacuum reactor is used to prepare N-methylmorpholine bromide [NMM] + Br - The oxidation is carried out under normal pressure by using a catalyst nano copper oxide dispersion.
[0059] Performance testing experiment
[0060] The brominated N-methylmorpholine N-oxide ionic liquid prepared in Examples 1-3 and Comparative Examples 1-2 was tested. Cellulose pulp (DP: 5.4-5.8 million) was used for the test of dissolving fibers. The solution with a water content of 17.5% and the weight of the fiber and the weight of the ionic liquid were the same. The dissolution operation was carried out under the conditions of heating to 80°C and strong stirring at 1200 rpm. In addition, the detection of ion polarity was carried out using ultraviolet spectroscopy. According to the maximum absorption wavelength of ions in the solution, the ionic polarity of the ionic liquid was corrected and calculated by using the polarity of water as a reference scalar.
[0061] The following data were obtained and organized into a table.
[0062] Performance test data of Examples 1-3 and Comparative Examples 1-2
[0063]
[0064] In Example 1, compared with Comparative Examples 1-2, the N-methylmorpholine bromide N-oxide ([NMMO]) prepared by vacuum catalysis and vacuum oxidation in the present application was obtained. + Br - ), with higher yields and [NMMO] + Br - The purity of the product is improved, the ionic polarity is better, and the brominated N-methylmorpholine N-oxide ([NMMO] + Br - ) has the ability to dissolve fiber faster.
[0065] Among them, a comparative study of NMMO for dissolving cellulose pulp (DP; 5.4-5.8 million) showed that in the same solution with a water content of 17.5%, the complete dissolution time of NMMO was 6 hours, while the bromination degree of 10%, 50%, and 80% [NMMO] + Br - The dissolution time is 2, 1.75, and 1.5 hours, which can significantly reduce the dissolution time, thereby reducing the energy consumption of the process and reducing the complexity of the recycling process.
[0066] In addition, refer to Figure 2 , wherein the H NMR spectra of different bromination degrees of Examples 1-3 are analyzed, that is, for brominated N-methylmorpholine N-oxide ([NMMO] + Br - ) characterization, proving that after bromination substitution, the distribution of characteristic peaks of the H NMR spectrum is compressed. In addition, Figure 3 The appearance of the ionic liquids of different bromination degrees in Examples 1-3 is shown in Figure 1, wherein the brominated N-methylmorpholine N-oxide ([NMMO]+ Br - ) has a nearly colorless liquid appearance and does not change at room temperature for more than one year; in Example 2, N-methylmorpholine bromide N-oxide ([NMMO] + Br - ) has a yellowish colorless liquid appearance; and N-methylmorpholine bromide N-oxide ([NMMO] + Br - ) has the appearance of light yellow liquid.
[0067] It should be noted that the above-mentioned sequence of the embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above-mentioned specific embodiments of this specification are described. Other embodiments are within the scope of the attached claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
[0068] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
[0069] This specification and drawings are merely exemplary illustrations of the present application and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, a person skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the present application and its equivalents, the present application intends to include these modifications and variations.
Claims
1. A method for preparing N-methylmorpholine bromide N-oxide ionic liquid, characterized in that: The method comprises the following steps in sequence: preparing N-methylmorpholine bromide by vacuum catalysis and preparing N-methylmorpholine bromide N-oxide by vacuum oxidation; The vacuum catalytic preparation of N-methylmorpholine bromide comprises the following steps: S1. Stir and mix a certain amount of N-methylmorpholine, a bromination catalyst and deionized water under vacuum to obtain a mixed solution A; S2, heating the mixed liquid A to a certain temperature, adding a certain amount of bromination reactant during stirring, and cooling and filtering to obtain brominated N-methylmorpholine ionic liquid; The vacuum oxidation method for preparing N-methylmorpholine bromide N-oxide comprises the following steps: S3, mixing a certain mass of the N-methylmorpholine bromide ionic liquid, an oxidation catalyst and deionized water under vacuum to obtain a mixed liquid B; S4, after heating the mixed liquid B to a certain temperature, adding a certain amount of oxidation reactant, and maintaining the temperature to control the reaction time until the reaction end point, filtering to remove the catalyst, and distilling under reduced pressure to obtain N-methylmorpholine bromide N-oxide ion liquid.
2. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 1, characterized in that: In the S1 reaction step, the bromination catalyst is ferric bromide.
3. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 2, characterized in that: In the S2 reaction step, the bromination reactant is one or both of bromine and hydrogen bromide.
4. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 1, characterized in that: In the S3 reaction step, the oxidation catalyst is nano copper oxide.
5. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 4, characterized in that: In the S4 reaction step, the oxidation reactant is hydrogen peroxide.
6. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 1, characterized in that: It also includes a method for preparing a low-bromination-degree N-methylmorpholine N-oxide ion liquid, a method for preparing a medium-bromination-degree N-methylmorpholine N-oxide ion liquid, and a method for preparing a high-bromination-degree N-methylmorpholine N-oxide ion liquid.
7. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 6, characterized in that: In the method for preparing the N-methylmorpholine N-oxide ionic liquid with a low degree of bromination (8-30%), the weight ratio of the N-methylmorpholine, the catalyst, the bromination reactant and the deionized water is (45.0-65.0): (0.1-0.3): (8.0-12.0): (22.7-46.9); The bromination reactant is bromine.
8. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 6, characterized in that: The method for preparing the N-methylmorpholine N-oxide ionic liquid with a moderate (30-60%) bromination degree comprises the following steps: the weight ratio of the N-methylmorpholine, the catalyst, the bromination reactant and the deionized water is (35.1-45.2): (2.5-3): (10.8-16.8): (35.0-51.6); and the bromination reactant is hydrogen bromide.
9. The method for preparing N-methylmorpholine bromide N-oxide ionic liquid according to claim 6, characterized in that: The method for preparing the N-methylmorpholine N-oxide ionic liquid with a high (60-90%) bromination degree is as follows: the weight ratio of the N-methylmorpholine, the catalyst, the bromination reactant and the deionized water is (15.8-32.2): (4.0-8.0): (18.5-33.2): (26.6-61.7); the bromination reactant is a mixture of bromine and hydrogen bromide in a weight ratio of 1:
1.
10. A brominated N-methylmorpholine N-oxide ionic liquid, characterized in that: The method is used to prepare the N-methylmorpholine bromide N-oxide ion liquid according to any one of claims 1 to 9.