Asymmetric quaternary ammonium base as well as preparation method and application thereof

Abstract

The invention provides asymmetric quaternary ammonium base as well as a preparation method and application thereof, and belongs to the technical field of organic chemistry. Comprising the following steps: mixing halide and tri-n-propylamine, adding into a solvent, heating and stirring for reaction, removing the solvent under reduced pressure, dissolving into water to prepare a solution, and preparing the asymmetric quaternary ammonium base by using bipolar membrane electrodialysis. According to the preparation method of the asymmetric quaternary ammonium base, firstly, the asymmetric quaternary ammonium salt is prepared through a chemical synthesis method, then the asymmetric quaternary ammonium base is prepared through bipolar membrane electrodialysis, the preparation method is simple and efficient, the prepared product is high in yield and mild in condition, and the asymmetric quaternary ammonium base can serve as a template agent to be used in the preparation process of a molecular sieve; wide application prospects are realized.

Description

Technical Field

[0001] The 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 with different R groups.

[0003] A chiral quaternary ammonium base is a quaternary ammonium base having a chiral center, especially when the nitrogen center of the quaternary ammonium base is chiral, i.e., different configurations of the center will result in different optical activities of the molecule. An asymmetric quaternary ammonium base can be a chiral quaternary ammonium base if the stereochemical configuration of its nitrogen center is different, so that the molecule has different optical isomers.

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

[0005] Electrochemical membrane reactor method: The synthesis of quaternary ammonium bases is carried out by 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 avoid contact between the product and the electrodes). This method is used to synthesize tetrabutylammonium hydroxide (TBAOH) from quaternary ammonium salts (such as tetrabutylammonium bromide, TBABr) by in situ ion substitution.

[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 includes two steps: tertiary amination and quaternization. In the tertiary amination step, a primary alcohol and a secondary amine are used as reaction raw materials, heated to 140-180° C. for dehydration reaction for 60-240 minutes under the catalytic action of a tertiary amination catalyst, and a tertiary amine is obtained after purification. In the quaternization step, the tertiary amine is dissolved in an organic solvent, a haloalkane is added, and the product is recovered after heating and reflux reaction to obtain a quaternary ammonium salt. The method for preparing a quaternary ammonium base using a quaternary ammonium salt includes adding water to the quaternary ammonium salt to prepare a quaternary ammonium salt aqueous solution, and obtaining the quaternary ammonium base through electrolysis. This method has the advantage of low energy consumption, but the preparation process is complicated and is not conducive to industrial application. Summary of the invention

[0007] The invention aims to provide an asymmetric quaternary ammonium base and a preparation method and application thereof. Firstly, a chemical synthesis method is adopted to prepare an asymmetric quaternary ammonium salt, and then a bipolar membrane electrodialysis is used to prepare the asymmetric quaternary ammonium base. 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 in this way:

[0009] The invention provides a method for preparing an asymmetric quaternary ammonium base, comprising the following steps: mixing a halide and tri-n-propylamine into a solvent, heating and stirring for reaction, 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 15-20wt%.

[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 asymmetric quaternary ammonium bases including ethyl-tri-n-propylammonium hydroxide, vinyl-tri-n-propylammonium hydroxide, propenyl-tri-n-propylammonium hydroxide, butenyl tri-n-propylammonium hydroxide, pentenyl tri-n-propylammonium hydroxide and the like are prepared. The asymmetric quaternary ammonium salt is firstly 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 prepared 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 a molecular sieve, and has broad application prospects.

[0020] Tri-n-propylamine will produce pigments when stored for a long time. The present invention also removes pigments efficiently and has a long service life by adding a reusable and easily separable adsorbent. The adsorbent uses activated carbon as a carrier, deposits magnetic ferroferric oxide by loading, and the surface is alternately modified by dopamine and tannic acid, so that the prepared adsorbent has a good adsorption effect, and the surface has abundant hydroxyl, amino, and carboxyl groups, which can have a good adsorption and fixation effect on pigment molecules by forming van der Waals forces such as hydrogen bonds. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 pH to 9 under nitrogen protection, 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. 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;

[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 were added, heated to 40 ° C, stirred for 1 h, 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 value of the solution to 10 under nitrogen protection, 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. 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;

[0032] S3. Add 10 g of polydopamine-modified magnetic activated carbon to 200 mL of water, add 6 g of tannic acid and 1 g of catalyst, heat to 50 ° C, stir and react for 3 h, separate with a magnet, wash, and dry 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 10g activated carbon to 200mL water, add 3.24g ferric chloride and 1.26g ferrous chloride, adjust the solution pH to 9.5 under nitrogen protection, heat to 95°C, stir and react for 4h, filter, wash, dry, and calcine at 450°C for 2h to obtain magnetic activated carbon;

[0037] 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;

[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 were added, heated to 45 ° C, stirred for 2 h, 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 10g activated carbon to 200mL water, add 3.24g ferric chloride and 1.26g ferrous chloride, adjust the solution pH to 9.5 under nitrogen protection, heat to 95°C, stir and react for 4h, filter, wash, dry, and calcine at 450°C for 2h 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 10g activated carbon to 200mL water, add 3.24g ferric chloride and 1.26g ferrous chloride, adjust the solution pH to 9.5 under nitrogen protection, heat to 95°C, stir and react for 4h, filter, wash, dry, and calcine at 450°C for 2h 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. The molar ratio of 4-bromobutene to tri-n-propylamine was 1:1. The mixture was heated to 75° C. and stirred for reaction 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 % tetrapropylammonium hydroxide aqueous solution 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. The molar ratio of allyl chloride to tri-n-propylamine was 1:1. The mixture was heated to 120°C and stirred for reaction 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 reaction 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] It can be seen from the above table that the yield of the asymmetric quaternary ammonium base prepared by the method in Examples 1-3 of the present invention is higher and the purity of the product is higher.

[0070] Test Example 2

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

[0072] Table 2

[0073]

[0074]

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

Claims

1. A method for preparing an asymmetric quaternary ammonium base, characterized in that: The method comprises 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 an asymmetric quaternary ammonium base by bipolar membrane electrodialysis.

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 brominated compound is selected from at least one of 4-bromobutene, 1-bromoethane, allyl chloride, vinyl bromide, and 2-bromo-2-pentene.

4. 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.

5. 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.

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

7. The preparation method according to claim 1, characterized in that: The polar liquid used in the bipolar membrane electrodialysis is a 1-2 wt % tetrapropylammonium hydroxide aqueous solution.

8. An asymmetric quaternary ammonium base obtained by the preparation method according to any one of claims 1 to 7.

9. Use of the asymmetric quaternary ammonium base as claimed in claim 8 as a template agent in the preparation of molecular sieves.

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