Asymmetric quaternary ammonium base and its preparation method and application

Abstract

The present invention provides an asymmetric quaternary ammonium base, its preparation method, and application, belonging to the field of organic chemistry technology. The method comprises the following steps: adding a halide and tri-n-propylamine to a solvent, heating and stirring the mixture to react, removing the solvent under reduced pressure, dissolving the mixture in water to form a solution, and preparing the asymmetric quaternary ammonium base using bipolar membrane electrodialysis. The present invention provides a method for preparing an asymmetric quaternary ammonium base. The method first uses chemical synthesis to prepare an asymmetric quaternary ammonium salt, and then uses bipolar membrane electrodialysis to prepare the asymmetric quaternary ammonium base. The method is simple, efficient, and produces a high product yield under mild conditions. The method can be used as a template in the preparation of molecular sieves, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of organic chemistry, and in particular to an asymmetric quaternary ammonium base and a preparation method and application thereof. Background Art

[0002] Quaternary ammonium hydroxide is a chemical substance with the general formula R4NOH, where R can be four identical or different aliphatic or aromatic groups. Asymmetric quaternary ammonium hydroxide refers to a quaternary ammonium hydroxide in which the R groups are not identical.

[0003] A chiral quaternary ammonium base is a quaternary ammonium base having a chiral center, particularly when the nitrogen center of the quaternary ammonium base is chiral, i.e., different configurations of the center result in different optical activities of the molecule. An asymmetric quaternary ammonium base can be chiral if the stereochemical configuration of the nitrogen center differs, resulting in different optical isomers.

[0004] The preparation method of asymmetric quaternary ammonium base mainly includes:

[0005] Electrochemical membrane reactor method: Quaternary ammonium bases are synthesized using electrochemical membrane reactors (EMRs). This method involves a two-compartment EMR-2 (catholyte and anolyte separated by an anion exchange membrane) and a three-compartment EMR-3 (three compartments separated by two anion exchange membranes to prevent product contact with the electrodes). This method is used to synthesize tetrabutylammonium hydroxide (TBAOH) from quaternary ammonium salts (such as tetrabutylammonium bromide, TBABr) by in situ ion replacement.

[0006] A method for preparing a quaternary ammonium salt and a method for preparing a quaternary ammonium base using a quaternary ammonium salt: This method comprises two steps: tertiary amination and quaternization. In the tertiary amination step, a primary alcohol and a secondary amine are used as reaction materials, heated to 140-180°C under the catalytic action of a tertiary amination catalyst for a dehydration reaction for 60-240 minutes, and purified to produce a tertiary amine. In the quaternization step, the tertiary amine is dissolved in an organic solvent, an alkyl halide is added, and the mixture is heated under reflux for a reaction, followed by recovery of the product to produce a quaternary ammonium salt. The method for preparing a quaternary ammonium base using a quaternary ammonium salt comprises adding water to the quaternary ammonium salt to prepare a quaternary ammonium salt aqueous solution, which is then electrolyzed to produce the quaternary ammonium base. This method has the advantage of low energy consumption, but the preparation process is complex, making it difficult to commercialize. Summary of the Invention

[0007] The present invention aims to provide an asymmetric quaternary ammonium base, a preparation method thereof, and an application thereof. The asymmetric quaternary ammonium salt is first prepared by a chemical synthesis method, and then the asymmetric quaternary ammonium base is prepared by bipolar membrane electrodialysis. The preparation method is simple and efficient, the yield of the obtained product is high, and the conditions are mild. The asymmetric quaternary ammonium base can be used as a template agent in the preparation process of molecular sieves, and has broad application prospects.

[0008] The technical solution of the present invention is achieved as follows:

[0009] The invention provides a preparation method of an asymmetric quaternary ammonium base, comprising the following steps: mixing a halide and tri-n-propylamine into a solvent, heating and stirring to react, removing the solvent under reduced pressure, dissolving the mixture in water to prepare a solution, and preparing the asymmetric quaternary ammonium base by bipolar membrane electrodialysis.

[0010] As a further improvement of the present invention, the molar ratio of the halide to tri-n-propylamine is 0.95-1.05:1.

[0011] As a further improvement of the present invention, the brominated compound is selected from at least one of 4-bromobutene, 1-bromoethane, allyl chloride, vinyl bromide, and 2-bromo-2-pentene.

[0012] As a further improvement of the present invention, the solvent is selected from at least one of acetonitrile, DMF, dichloromethane, ethyl acetate, petroleum ether, and acetone.

[0013] As a further improvement of the present invention, the temperature of the heating and stirring reaction is 75-120° C., and the time is 1-8 hours.

[0014] As a further improvement of the present invention, the concentration of the solution is 15-20 wt%.

[0015] As a further improvement of the present invention, the polar liquid used in the bipolar membrane electrodialysis is a 1-2 wt % tetrapropylammonium hydroxide aqueous solution.

[0016] The present invention further protects an asymmetric quaternary ammonium base prepared by the above preparation method.

[0017] The present invention further protects the use of the above-mentioned asymmetric quaternary ammonium base as a template agent in the preparation of molecular sieves.

[0018] The present invention has the following beneficial effects:

[0019] The invention provides a method for preparing an asymmetric quaternary ammonium base. The method prepares asymmetric quaternary ammonium bases including ethyl-tri-n-propylammonium hydroxide, vinyl-tri-n-propylammonium hydroxide, propenyl-tri-n-propylammonium hydroxide, butenyltri-n-propylammonium hydroxide, pentenyltri-n-propylammonium hydroxide and the like. The method first adopts a chemical synthesis method to prepare the asymmetric quaternary ammonium salt, and then utilizes bipolar membrane electrodialysis to prepare the asymmetric quaternary ammonium base. The preparation method is simple and efficient, the yield of the prepared product is high, and the conditions are mild. The method can be used as a template agent in the preparation process of molecular sieves, and has broad application prospects.

[0020] Tri-n-propylamine can produce pigments when stored for long periods of time. The present invention also effectively removes pigments and prolongs its service life by adding a reusable and easily separable adsorbent. The adsorbent uses activated carbon as a carrier, depositing magnetic ferroferric oxide on it. The surface is alternatingly modified with dopamine and tannic acid, resulting in a highly effective adsorption agent. The surface is rich in hydroxyl, amino, and carboxyl groups, effectively adsorbing and fixing pigment molecules through van der Waals forces such as hydrogen bonding. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] Preparation Example 1 Preparation of adsorbent

[0023] The following steps are involved:

[0024] S1. Add 10 g of activated carbon to 200 mL of water, add 3.24 g of ferric chloride and 1.26 g of ferrous chloride, adjust the solution to pH 9 under nitrogen, heat to 90°C, stir and react for 3 h, filter, wash, dry, and calcine at 400°C for 1 h to obtain magnetic activated carbon;

[0025] S2. 10 g of magnetic activated carbon was added to 200 mL of water, 4 g of dopamine hydrochloride, and 0.5 g of catalyst. The mixture was heated to 40°C and stirred for 1 h. The mixture was separated by magnet, washed, and dried to obtain polydopamine-modified magnetic activated carbon.

[0026] S3. 10 g of polydopamine-modified magnetic activated carbon was added to 200 mL of water, 4 g of tannic acid, and 0.5 g of catalyst. The mixture was heated to 40°C and stirred for 1 h. The mixture was separated by a magnet, washed, and dried to obtain an adsorbent.

[0027] The catalyst is a Tris-HCl solution with a pH of 8.5.

[0028] Preparation Example 2 Preparation of adsorbent

[0029] The following steps are involved:

[0030] S1. Add 10 g of activated carbon to 200 mL of water, add 3.24 g of ferric chloride and 1.26 g of ferrous chloride, adjust the pH of the solution to 10 under nitrogen, heat to 100 ° C, stir and react for 5 h, filter, wash, dry, and calcine at 500 ° C for 3 h to obtain magnetic activated carbon;

[0031] S2. 10 g of magnetic activated carbon was added to 200 mL of water, 6 g of dopamine hydrochloride, and 1 g of catalyst. The mixture was heated to 50°C and stirred for 3 h. The mixture was separated by magnet, washed, and dried to obtain polydopamine-modified magnetic activated carbon.

[0032] S3. 10 g of polydopamine-modified magnetic activated carbon was added to 200 mL of water, 6 g of tannic acid, and 1 g of catalyst. The mixture was heated to 50 ° C and stirred for 3 h. The mixture was separated by a magnet, washed, and dried to obtain an adsorbent.

[0033] The catalyst is a Tris-HCl solution with a pH of 9.5.

[0034] Preparation Example 3 Preparation of adsorbent

[0035] The following steps are involved:

[0036] S1. Add 10 g of activated carbon to 200 mL of water, add 3.24 g of ferric chloride and 1.26 g of ferrous chloride, adjust the pH of the solution to 9.5 under nitrogen, heat to 95°C, stir and react for 4 h, filter, wash, dry, and calcine at 450°C for 2 h to obtain magnetic activated carbon;

[0037] S2. 10 g of magnetic activated carbon was added to 200 mL of water, 5 g of dopamine hydrochloride, and 0.7 g of catalyst. The mixture was heated to 45 ° C and stirred for 2 h. The mixture was separated by magnet, washed, and dried to obtain polydopamine-modified magnetic activated carbon.

[0038] S3. 10 g of polydopamine-modified magnetic activated carbon was added to 200 mL of water, 5 g of tannic acid, and 0.7 g of catalyst. The mixture was heated to 45 ° C and stirred for 2 h. The mixture was separated by a magnet, washed, and dried to obtain an adsorbent.

[0039] The catalyst is a Tris-HCl solution with a pH of 9.

[0040] Comparative Preparation Example 1

[0041] Compared with Preparation Example 3, the difference is that step S2 is not performed.

[0042] The details are as follows:

[0043] S1. Add 10 g of activated carbon to 200 mL of water, add 3.24 g of ferric chloride and 1.26 g of ferrous chloride, adjust the pH of the solution to 9.5 under nitrogen, heat to 95°C, stir and react for 4 h, filter, wash, dry, and calcine at 450°C for 2 h to obtain magnetic activated carbon;

[0044] S2. Add 10 g of magnetic activated carbon to 200 mL of water, add 5 g of tannic acid and 0.7 g of catalyst, heat to 45°C, stir and react for 2 h, separate with a magnet, wash, and dry to obtain an adsorbent;

[0045] The catalyst is a Tris-HCl solution with a pH of 9.

[0046] Comparative Preparation Example 2

[0047] Compared with Preparation Example 3, the difference is that step S3 is not performed.

[0048] The details are as follows:

[0049] S1. Add 10 g of activated carbon to 200 mL of water, add 3.24 g of ferric chloride and 1.26 g of ferrous chloride, adjust the pH of the solution to 9.5 under nitrogen, heat to 95°C, stir and react for 4 h, filter, wash, dry, and calcine at 450°C for 2 h to obtain magnetic activated carbon;

[0050] S2. Add 10 g of magnetic activated carbon to 200 mL of water, add 5 g of dopamine hydrochloride and 0.7 g of catalyst, heat to 45°C, stir and react for 2 h, separate with a magnet, wash, and dry to obtain polydopamine-modified magnetic activated carbon, which is the adsorbent;

[0051] The catalyst is a Tris-HCl solution with a pH of 9.

[0052] Example 1

[0053] This embodiment provides a method for preparing an asymmetric quaternary ammonium base, comprising the following steps:

[0054] The adsorbent prepared in Preparation Example 1 was added to tri-n-propylamine. After adsorption for 1 hour, the adsorbent was separated by a magnet. 4-bromobutene and tri-n-propylamine were mixed and added to acetonitrile in a molar ratio of 1:1. The mixture was heated to 75° C. and stirred for 6 hours. The acetonitrile was removed under reduced pressure and dissolved in water to prepare a solution with a concentration of 15 wt%. An asymmetric quaternary ammonium base was prepared by bipolar membrane electrodialysis using a 1 wt % aqueous solution of tetrapropylammonium hydroxide as the polar liquid.

[0055] Example 2

[0056] This embodiment provides a method for preparing an asymmetric quaternary ammonium base, comprising the following steps:

[0057] The adsorbent prepared in Preparation Example 2 was added to tri-n-propylamine. After adsorption for 1 hour, the adsorbent was separated by a magnet. Allyl chloride and tri-n-propylamine were mixed and added to acetonitrile in a molar ratio of 1:1. The mixture was heated to 120°C and stirred for 6 hours. The acetonitrile was removed under reduced pressure and dissolved in water to prepare a solution with a concentration of 20 wt%. An asymmetric quaternary ammonium base was prepared by bipolar membrane electrodialysis using a 2 wt % aqueous solution of tetrapropylammonium hydroxide as the polar liquid.

[0058] Example 3

[0059] This embodiment provides a method for preparing an asymmetric quaternary ammonium base, comprising the following steps:

[0060] The adsorbent prepared in Preparation Example 3 was added to tri-n-propylamine. After adsorption for 1 hour, the adsorbent was separated by a magnet. Vinyl bromide and tri-n-propylamine were mixed and added to acetonitrile in a molar ratio of 1:1. The mixture was heated to 100° C. and stirred for 6 hours. The acetonitrile was removed under reduced pressure and dissolved in water to prepare a solution with a concentration of 17 wt%. An asymmetric quaternary ammonium base was prepared by bipolar membrane electrodialysis using a 1.5 wt % aqueous solution of tetrapropylammonium hydroxide as the polar liquid.

[0061] Comparative Example 1

[0062] Compared with Example 3, the difference is that the adsorbent is prepared by Comparative Preparation Example 1.

[0063] Comparative Example 2

[0064] Compared with Example 3, the difference is that the adsorbent is prepared by Comparative Preparation Example 2.

[0065] Test Example 1

[0066] The reactions in Examples 1-3 and Comparative Examples 1-2 were evaluated, and the results are shown in Table 1.

[0067] Table 1

[0068] Group Yield of asymmetric quaternary ammonium base (%) Purity of asymmetric quaternary ammonium base (%) Example 1 98.5 99.2 Example 2 98.9 99.5 Example 3 99.4 99.9 Comparative Example 1 96.7 95.5 Comparative Example 2 97.8 94.2

[0069] As can be seen from the above table, the yield of the asymmetric quaternary ammonium base prepared by the method in Examples 1-3 of the present invention is high and the purity of the product is high.

[0070] Test Example 2

[0071] The adsorbent in Example 3 was separated, washed, and dried. The operation in Example 3 was repeated 5 times to adsorb tri-n-propylamine. The reaction in Example 3 was repeated, and the reaction results were evaluated. The results are shown in Table 2.

[0072] Table 2

[0073]

[0074]

[0075] As can be seen from the above table, the adsorbents in Examples 1-3 of the present invention can still maintain a high adsorption efficiency after multiple adsorptions, so that after multiple repetitions, the purity of the obtained asymmetric quaternary ammonium base product remains high.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an asymmetric quaternary ammonium base, characterized in that: The method comprises the following steps: adding a halide and tri-n-propylamine to a solvent, heating and stirring to react, removing the solvent under reduced pressure, dissolving the mixture in water to prepare a solution, and using bipolar membrane electrodialysis to prepare an asymmetric quaternary ammonium base; the halide is selected from at least one of 4-bromobutene, 1-bromoethane, allyl chloride, vinyl bromide, and 2-bromo-2-pentene; and the polar liquid used in the bipolar membrane electrodialysis is a 1-2 wt% tetrapropylammonium hydroxide aqueous solution. The prepared adsorbent is added to tri-n-propylamine, and after adsorption for 1 hour, the adsorbent is separated by a magnet. The preparation method of the adsorbent comprises the following steps: S1. Add 10 g of activated carbon to 200 mL of water, along with 3.24 g of ferric chloride and 1.26 g of ferrous chloride. Under nitrogen, adjust the solution to a pH of 9.

5. Heat to 95°C, stir, and react for 4 h. Filter, wash, dry, and calcine at 450°C for 2 h to produce magnetic activated carbon. S2. Add 10 g of magnetic activated carbon to 200 mL of water, add 5 g of dopamine hydrochloride, and 0.7 g of catalyst. Heat to 45°C and stir for 2 h. Separate with a magnet, wash, and dry to obtain polydopamine-modified magnetic activated carbon. S3. Add 10 g of polydopamine-modified magnetic activated carbon to 200 mL of water, along with 5 g of tannic acid and 0.7 g of a catalyst. Heat to 45°C and stir for 2 h. Separate with a magnet, wash, and dry to obtain an adsorbent. The catalyst is a Tris-HCl solution with a pH of 9; Alternatively, the preparation method of the adsorbent comprises the following steps: S1. Add 10 g of activated carbon to 200 mL of water, along with 3.24 g of ferric chloride and 1.26 g of ferrous chloride. Under nitrogen, adjust the solution to a pH of 10. Heat to 100°C, stir, and react for 5 h. Filter, wash, dry, and calcine at 500°C for 3 h to produce magnetic activated carbon. S2. Add 10 g of magnetic activated carbon to 200 mL of water, add 6 g of dopamine hydrochloride, and 1 g of catalyst, heat to 50°C, stir and react for 3 h, separate with a magnet, wash, and dry to obtain polydopamine-modified magnetic activated carbon. S3. 10 g of polydopamine-modified magnetic activated carbon was added to 200 mL of water, along with 6 g of tannic acid and 1 g of catalyst. The mixture was heated to 50°C and stirred for 3 h. The mixture was separated by a magnetic separator, washed, and dried to obtain an adsorbent. The catalyst is a Tris-HCl solution with a pH of 9.5; Alternatively, the preparation method of the adsorbent comprises the following steps: S1. Add 10 g of activated carbon to 200 mL of water, along with 3.24 g of ferric chloride and 1.26 g of ferrous chloride. Under nitrogen, adjust the solution to pH 9. Heat to 90°C, stir, and react for 3 h. Filter, wash, dry, and calcine at 400°C for 1 h to produce magnetic activated carbon. S2. Add 10 g of magnetic activated carbon to 200 mL of water, add 4 g of dopamine hydrochloride, and 0.5 g of catalyst, heat to 40°C, stir and react for 1 h, separate with a magnet, wash, and dry to obtain polydopamine-modified magnetic activated carbon. S3. 10 g of polydopamine-modified magnetic activated carbon was added to 200 mL of water, along with 4 g of tannic acid and 0.5 g of a catalyst. The mixture was heated to 40°C and stirred for 1 h. The mixture was separated by a magnetic separator, washed, and dried to obtain an adsorbent. The catalyst is a Tris-HCl solution with a pH of 8.

5.

2. The preparation method according to claim 1, characterized in that The molar ratio of the halide to tri-n-propylamine is 0.95-1.05:

1.

3. The preparation method according to claim 1, characterized in that The solvent is selected from at least one of acetonitrile, DMF, dichloromethane, ethyl acetate, petroleum ether and acetone.

4. The preparation method according to claim 1, characterized in that The temperature of the heating and stirring reaction is 75-120° C., and the time is 1-8 hours.

5. The preparation method according to claim 1, characterized in that The concentration of the solution is 15-20 wt %.

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