Amphoteric ion exchange resin as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of separation resin, and relates to amphoteric ion exchange resin as well as a preparation method and application thereof. The amphoteric ion exchange resin is obtained by introducing a monomer 3-[N, N-dimethyl-[2-(2-methylpropane-2-enoyloxy) ethyl] ammonium] propane-1-sulfonic acid inner salt and a monomer methacryloyloxyethyl trimethyl ammonium chloride into chloromethylated polystyrene resin through an atom transfer radical polymerization reaction. Quaternary ammonium salt groups exposed on 3-[N, N-dimethyl-[2-(2-methylpropyl-2-enoyloxy) ethyl] ammonium] propane-1-sulfonic acid inner salt and methacryloyloxyethyl trimethyl ammonium chloride in the amphoteric ion exchange resin can improve the separation rate of acid and sugar; and meanwhile, during elution, sulfonate groups on 3-[N, N-dimethyl-[2-(2-methylpropane-2-enoyloxy) ethyl] ammonium] propane-1-sulfonic acid inner salt in the resin can effectively weaken the sulfuric acid tailing phenomenon by virtue of the sulfonate groups on the 3-[N, N-dimethyl-[2-(2-methylpropane-2-enoyloxy) ethyl] ammonium] propane-1-sulfonic acid inner salt.

Description

Technical Field

[0001] The present invention belongs to the technical field of separation resins, and relates to an amphoteric ion exchange resin, a preparation method thereof and an application thereof. Background Art

[0002] Using agricultural straw biomass as a raw material to produce biofuels and bio-based chemicals, etc., can solve problems such as high carbon emissions and environmental pollution caused by the consumption of fossil resources. In the production process of biofuels and bio-based chemicals, the most core issue is how to obtain fermentable sugars from the raw materials. Concentrated acid hydrolysis can obtain fermentable sugars under mild conditions at atmospheric pressure, with significant advantages of low energy consumption, low toxic by-products, and no need for cellulase input. Among them, sulfuric acid is the most commonly used. In order to reduce costs and reduce the environmental load, sulfuric acid must be recycled and reused. Therefore, the separation of sulfuric acid and sugars must be carried out. So, the separation of acid sugars (such as sulfuric acid, glucose, etc.) is a crucial step. Most traditional acid sugar separation technologies use ion exchange resins to complete this process.

[0003] However, there are various problems with existing ion exchange resins: (1) Poor separation problem: In the process of separating acid sugars with traditional cation exchange resins, there is often a phenomenon of poor separation, resulting in low purity of sulfuric acid and sugars, so that the separation efficiency is low. (2) Sulfuric acid tailing problem: In the process of separating acid sugars with traditional resins, there is often a sulfuric acid tailing phenomenon, resulting in a low recovery concentration of sulfuric acid, affecting the subsequent treatment process and increasing the concentration cost. (3) Low separation efficiency: Due to the relatively simple structure of existing resins, their separation efficiency is poor when facing different types of acid sugars, and cannot meet the requirements of efficient separation.

[0004] Therefore, there is an urgent need for a new type of acid sugar separation resin that can overcome the above disadvantages, especially in maintaining a high separation efficiency, and can weaken or eliminate the sulfuric acid tailing phenomenon, thereby improving the separation efficiency of acid sugars and reducing the concentration cost. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an amphoteric ion exchange resin, a preparation method thereof and an application thereof in view of the deficiencies of the prior art.

[0006] Inventive concept: The acid-sugar separation resin of the present invention is obtained by polymerizing chloromethylated polystyrene resin with monomer 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt and monomer methacryloyloxyethyl trimethylammonium chloride through ATRP reaction. After the reaction, the loading amount of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt in the resin is 0.2 - 2.0 mmol / g, and the loading amount of methacryloyloxyethyl trimethylammonium chloride is 0.1 - 1.5 mmol / g. The acid-sugar separation resin provided by the present invention is a novel strongly basic zwitterionic exchange resin. When loading samples, the exposed quaternary ammonium salt groups on 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt and methacryloyloxyethyl trimethylammonium chloride can improve the separation rate of acid and sugar; meanwhile, when eluting, the sulfonate groups on 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt in the resin can effectively weaken the sulfuric acid tailing phenomenon; the resin provided by the present invention has excellent acid-sugar separation effect, and the sulfuric acid elution is easier, and the acid tailing phenomenon is eliminated, thereby improving the recovery efficiency of sulfuric acid and reducing the cost of subsequent sulfuric acid concentration.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] The present invention discloses a zwitterionic exchange resin, and the structural formula of the zwitterionic exchange resin is shown as follows:

[0009]

[0010] Wherein,

[0011] PS represents polystyrene microspheres;

[0012] m is a positive number greater than 0;

[0013] n is a positive number greater than 0;

[0014] Among them, m unit structures and n unit structures are randomly copolymerized.

[0015] In some embodiments, preferably, m is a positive integer greater than 0; n is a positive integer greater than 0.

[0016] In some embodiments, preferably, the ratio of m to n is (0.5 - 4):(0.25 - 2).

[0017] In some embodiments, the zwitterionic exchange resin is obtained by introducing 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt monomer and methacryloyloxyethyl trimethylammonium chloride monomer into chloromethylated polystyrene resin through atom transfer radical polymerization reaction;

[0018] The loading amount of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt in the zwitterionic exchange resin is 0.2 - 2.0 mmol / g, and the loading amount of methacryloyloxyethyl trimethylammonium chloride is 0.1 - 1.5 mmol / g.

[0019] In some embodiments, preferably, the loading amount of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt in the zwitterionic exchange resin is 0.2 - 1.2 mmol / g, and the loading amount of methacryloyloxyethyl trimethylammonium chloride is 0.1 - 1.0 mmol / g.

[0020] In some embodiments, more preferably, the loading amount of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt in the zwitterionic exchange resin is 0.3 - 1.0 mmol / g, and the loading amount of methacryloyloxyethyl trimethylammonium chloride is 0.1 - 0.5 mmol / g.

[0021] Furthermore, the present invention provides a preparation method of the above-mentioned zwitterionic exchange resin. Mix the chloromethylated polystyrene resin with a solvent, soak and swell it, and then add 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt, methacryloyloxyethyl trimethylammonium chloride, a base and a catalyst to carry out a grafting reaction to obtain the zwitterionic exchange resin.

[0022] Among them, the particle size of the chloromethylated polystyrene resin is 3 μm - 20 μm.

[0023] In some embodiments, the solvent is any one or a combination of several of water, N,N-dimethylformamide, toluene, ethanol and tetrahydrofuran; the base is any one or a combination of several of 2,2-bipyridine, triethylamine and pentamethyldiethylenetriamine; the catalyst is any one or a combination of several of copper chloride, copper bromide and ferrous chloride.

[0024] In some embodiments, preferably, the solvent is any one or a mixture of several solvents selected from N,N-dimethylformamide, toluene, ethanol, and tetrahydrofuran and water; more preferably, it is a mixture of water and N,N-dimethylformamide in any ratio; even more preferably, it is a mixture of water and N,N-dimethylformamide with a volume ratio of 1:(2 - 4); most preferably, it is a mixture of water and N,N-dimethylformamide with a volume ratio of 1:3.

[0025] In some embodiments, preferably, the base is 2,2-bipyridine.

[0026] In some embodiments, preferably, the catalyst is cuprous chloride.

[0027] In some embodiments, the ratio of the mass dosage of the chloromethylated polystyrene resin to the volume dosage of the solvent is 2.5 g:40 - 70 mL.

[0028] In some embodiments, preferably, the ratio of the mass dosage of the chloromethylated polystyrene resin to the volume dosage of the solvent is 2.5 g:50 - 60 mL, and more preferably 2.5 g:56 mL.

[0029] In some embodiments, the molar ratio of chlorine in the chloromethylated polystyrene resin to 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate inner salt and methylacryloyloxyethyltrimethylammonium chloride is 1:(20 - 50):(10 - 25); the mass ratio of the chloromethylated polystyrene resin to the base and the catalyst is (2.00 - 3.00):(1.25 - 1.60):(0.40 - 0.55).

[0030] In some embodiments, preferably, the molar ratio of chlorine in the chloromethylated polystyrene resin to 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate inner salt and methylacryloyloxyethyltrimethylammonium chloride is 1:30:15.

[0031] In some embodiments, preferably, the mass ratio of the chloromethylated polystyrene resin to the base and the catalyst is 2.50:(1.25 - 1.60):(0.40 - 0.55), and more preferably 2.50:(1.50 - 1.60):(0.45 - 0.55).

[0032] In some embodiments, for the soaking and swelling, the soaking time is 2 - 5 h; for the grafting reaction, the reaction temperature is 85°C - 110°C, and the reaction time is 10 - 16 h; the grafting reaction is carried out under the protection of an inert gas.

[0033] In some embodiments, preferably, for the immersion swelling, the immersion time is 2 to 3 h, more preferably 2 h; for the grafting reaction, the reaction temperature is 100 °C to 110 °C, more preferably 110 °C, and the reaction time is 10 to 14 h, more preferably 12 h.

[0034] In some embodiments, preferably, the inert gas is nitrogen.

[0035] The application of the above zwitterionic exchange resin in the separation of sugar acids is also within the protection scope of the present invention.

[0036] Specifically, the sugar is any one or a combination of several of glucose, xylose, arabinose, and cellobiose; the acid is any one or a combination of several of sulfuric acid, hydrochloric acid, and phosphoric acid.

[0037] Specifically, preferably, the sugar is glucose; the acid is sulfuric acid.

[0038] Specifically, the zwitterionic exchange resin has the function of reducing acid tailing during the separation of sugar acids.

[0039] Specifically, before the zwitterionic exchange resin is used for separating sugar acids, it needs to be treated with a sulfuric acid aqueous solution with a concentration of 1 mol / L to 2 mol / L to obtain a pseudo-strongly basic zwitterionic exchange resin.

[0040] Beneficial effects:

[0041] (1) The zwitterionic exchange resin provided by the present invention can not only eliminate the influence of acid tailing, but also achieve baseline separation of sulfuric acid and glucose. In terms of acid tailing, due to the elimination ability of the sulfonic acid group on the zwitterionic monomer SBMA, the tailing problem of sulfuric acid disappears. And through the Donnan effect of the quaternary ammonium groups on the zwitterionic monomer SBMA and the strongly basic monomer DMC, sulfuric acid is adsorbed on the medium while glucose is not adsorbed, thus achieving baseline separation of the two.

[0042] (2) When the zwitterionic exchange resin provided by the present invention is used for separating sugar and acid, the recovery rate of sulfuric acid can reach 100%, and the purity of sulfuric acid can reach 100%; the recovery rate of glucose can reach 100%, and the purity of glucose can reach 100%.

[0043] (3) The zwitterionic exchange resin provided by the present invention has excellent acid-sugar separation effect, and sulfuric acid elution is easier, the acid tailing phenomenon is eliminated, and baseline separation of sugar and acid is achieved, thereby improving the recovery efficiency of sulfuric acid and reducing the cost of subsequent sulfuric acid concentration. Description of the drawings

[0044] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0045] Figure 1 For the PS-CH prepared in Examples 1 to 4 2 -P(SBMA-DMC) resin infrared spectrogram.

[0046] Figure 2 For the PS-CH prepared in Example 2 of the present invention 2 -P(SBMA-DMC) resin sugar acid separation performance diagram.

[0047] Figure 3 For the sugar acid separation performance diagram of commercial resin A-853E.

[0048] Figure 4 For the sugar acid separation performance diagram of commercial resin UBK-510L. Specific Embodiments

[0049] According to the following embodiments, the present invention can be better understood. However, those skilled in the art can easily understand that the content described in the embodiments is only used to illustrate the present invention and should not and will not limit the present invention detailed in the claims.

[0050] In the following embodiments, the experimental methods are all conventional methods unless otherwise specified; the reagents and materials are all commercially available unless otherwise specified.

[0051] 1. The chloromethylated polystyrene microspheres (PS-Cl) used in the embodiments of the present invention have a chlorine substitution degree of 2 mmol / g.

[0052] 2. The 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate (SBMA) used in the embodiments of the present invention, molecular formula: C 11 H 21 NO 5 S; molecular weight: 279.35.

[0053] 3. The methacryloyloxyethyltrimethylammonium chloride (DMC) used in the embodiments of the present invention, chemical formula: C 9 H 18 ClNO 2 ; molecular weight: 207.698.

[0054] 4. The 2’,2-bipyridine (Bipy) used in the embodiments of the present invention, molecular weight 156.19.

[0055] 5. The cuprous chloride (CuCl) used in the embodiments of the present invention has a molecular weight of 99.

[0056] Example 1: Preparation of Acid-Sugar Zwitterionic Exchange Resin

[0057] Add 2.5 g of PS-Cl with 2 mmol / g, 14 mL of H 2 O and 42 mL of DMF to a 250 mL three-necked flask (equipped with a stirrer paddle) and soak for 2 h; then add 27.9 g of SBMA and 10.375 g of DMC to the three-necked flask (where the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:20:10), evacuate, introduce nitrogen, repeat three times, then add 1.56 g of Bipy and 0.495 g of CuCl, evacuate, introduce nitrogen, repeat twice, place the three-necked flask in an oil bath at 110 °C, introduce a fixed amount of nitrogen, and carry out the grafting reaction for 12 h. After the reaction is completed, cool the reaction solution to room temperature in an ice-water bath, filter off the remaining solution by suction, wash it repeatedly with DMF 4 - 5 times, soak it in dilute hydrochloric acid for 0.5 h, wash it repeatedly with water and methanol 3 times, and dry it in vacuo at 40 °C to obtain 3.1 g of pseudo-strong basic zwitterionic exchange resin, denoted as PS-CH 2 -P(SBMA-DMC).

[0058] Example 2: Preparation of Acid-Sugar Zwitterionic Exchange Resin

[0059] Add 2.5 g of PS-Cl with 2 mmol / g, 14 mL of H 2 O and 42 mL of DMF to a 250 mL three-necked flask (equipped with a stirrer paddle) and soak for 2 h; then add 41.85 g of SBMA and 15.562 g of DMC to the three-necked flask (where the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:30:15), evacuate, introduce nitrogen, repeat three times, then add 1.56 g of Bipy and 0.495 g of CuCl, evacuate, introduce nitrogen, repeat twice, place the three-necked flask in an oil bath at 110 °C, introduce a fixed amount of nitrogen, and carry out the grafting reaction for 12 h. After the reaction is completed, cool the reaction solution to room temperature in an ice-water bath, filter off the remaining solution by suction, wash it repeatedly with DMF 4 - 5 times, soak it in dilute hydrochloric acid for 0.5 h, wash it repeatedly with water and methanol 3 times, and dry it in vacuo at 40 °C to obtain 4.2 g of pseudo-strong basic zwitterionic exchange resin, denoted as PS-CH 2 -P(SBMA-DMC).

[0060] Example 3: Preparation of Acid-Sugar Zwitterionic Exchange Resin

[0061] Add 2.5 g of PS-Cl with 2 mmol / g, 14 mL of H 2Soak in O and 42 mL of DMF for 2 h; then add 55.8 g of SBMA and 20.75 g of DMC to the three-necked flask (where the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:40:20), evacuate, introduce nitrogen, repeat three times, then add 1.56 g of Bipy and 0.495 g of CuCl, evacuate, introduce nitrogen, repeat twice, place the three-necked flask in an oil bath at 110 °C, introduce a fixed amount of nitrogen, and carry out the grafting reaction for 12 h. After the reaction is completed, cool the reaction solution to room temperature in an ice-water bath, filter off the remaining solution by suction, wash it repeatedly with DMF 4 - 5 times, soak it in dilute hydrochloric acid for 0.5 h, wash it repeatedly with water and methanol 3 times, and dry it under vacuum at 40 °C to obtain 3.5 g of pseudo-strongly basic zwitterionic exchange resin, denoted as PS-CH 2 -P(SBMA-DMC).

[0062] Example 4: Preparation of acid-sugar zwitterionic exchange resin

[0063] Add 2.5 g of PS-Cl with 2 mmol / g, 14 mL of H 2 O and 42 mL of DMF to a 250 mL three-necked flask (equipped with a stirrer paddle) and soak for 2 h; then add 69.75 g of SBMA and 25.937 g of DMC to the three-necked flask (where the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:50:25), evacuate, introduce nitrogen, repeat three times, then add 1.56 g of Bipy and 0.495 g of CuCl, evacuate, introduce nitrogen, repeat twice, place the three-necked flask in an oil bath at 110 °C, introduce a fixed amount of nitrogen, and carry out the grafting reaction for 12 h. After the reaction is completed, cool the reaction solution to room temperature in an ice-water bath, filter off the remaining solution by suction, wash it repeatedly with DMF 4 - 5 times, soak it in dilute hydrochloric acid for 0.5 h, wash it repeatedly with water and methanol 3 times, and dry it under vacuum at 40 °C to obtain 3.3 g of pseudo-strongly basic zwitterionic exchange resin, denoted as PS-CH 2 -P(SBMA-DMC).

[0064] Example 5:

[0065] (1) Carry out infrared detection on the PS-CH 2 -P(SBMA-DMC) prepared in Examples 1 - 4 respectively. After infrared analysis and testing, the results are as Figure 1 shown: Among them, spectral line a: PS-CH 2 -P(SBMA-DMC) (the molar ratio of chlorine in the charged PS-Cl to SBMA and DMC is 1:20:10); spectral line b: PS-CH 2 -P(SBMA-DMC) (the molar ratio of chlorine in the charged PS-Cl to SBMA and DMC is 1:30:15); spectral line c: PS-CH2 -P(SBMA-DMC) (the molar ratio of chlorine in the fed PS-Cl to SBMA and DMC is 1:40:20); Spectrum d: PS-CH 2 -P(SBMA-DMC) (the molar ratio of chlorine in the fed PS-Cl to SBMA and DMC is 1:50:25); Spectrum e: PS-Cl.

[0066] As can be seen from the figure, the hydrophilic medium PS-CH 2 -P(SBMA-DMC) at 1535 cm -1 is the vibration of C-N, and 1720 cm -1 is attributed to the vibration of C=O in the ester group. 1191 cm -1 and 1036 cm -1 correspond to the asymmetric vibration and symmetric vibration of S=O respectively, indicating the successful synthesis of the hydrophilic medium PS-CH 2 -P(SBMA-DMC).

[0067] (2) Calculate the loading amount of the product (PS-CH 2 -P(SBMA-DMC) prepared in Examples 1 to 4) according to the following formula. The specific results are shown in Table 1:

[0068] Quaternary ammonium group: LA 1 = [(W 2 - W 1 ) / (279 + 207.5)] / W 1 ;

[0069] Sulfonic acid group: LA 2 = 2 * LA 1 / 3;

[0070] In the above formula, W 1 and W 2 are the masses of the resin before and after the reaction respectively. Among them, 279 is the relative molecular mass of SBMA, and 207.5 is the relative molecular mass of DMC.

[0071] Table 1

[0072]

[0073] In summary, as can be seen from the above table, when the molar ratio of chlorine in the PS-Cl resin to the monomer SBMA and the monomer DMC is 1:30:15, the loading amounts of the quaternary ammonium group and the sulfonic acid group are the largest; in addition, according to the infrared spectrum Figure 1It can be seen that it can be determined that both the monomer SBMA and the monomer DMC have been successfully grafted onto the PS-Cl resin. Therefore, based on the combination of these two results, the optimal condition for this reaction is that the molar ratio of chlorine in the resin to the monomers SBMA and DMC is 1:30:15.

[0074] The purpose of the following examples is to provide a pseudo-strongly basic zwitterionic exchange resin as an adsorbent for column chromatography separation of a sulfuric acid / glucose mixture.

[0075] Example 6:

[0076] In this example, about 7 g of the zwitterionic exchange resin PS-g-P(SBMA-DMC) prepared in Example 2 (where the molar ratio of chlorine in PS-Cl to SBMA and DMC during feeding is 1:30:15) was packed into a glass column with a specification (inner diameter 1 cm, height 17 cm), then transformed with 100 mL of 1 mol / L sulfuric acid, and finally the sulfuric acid was washed clean with water. In the sample feed solution (a mixture of water, sulfuric acid, and glucose), the sulfuric acid was 40 g / L, the glucose was 130 g / L, the solvent was water, the sample loading volume was 4 mL, and then it was eluted with pure water until complete (no acid at the bottom of the column). Sulfuric acid and glucose were recovered. The recovery rate of sulfuric acid was 100%, and the purity of sulfuric acid was 100%; the recovery rate of glucose was 100%, and the purity of glucose was 100%.

[0077] Using high-performance liquid chromatography refractive index detection method, with 5 mmol / L sulfuric acid as the mobile phase, the detection temperature was 55 °C, and the flow rate was 0.6 mL / min. The chromatogram is as Figure 2 shown. It can be seen from Figure 2 that for adjacent two components, the R (resolution) ≥ 1.5. The chromatographic column filled with PS-g-P(SBMA-DMC) according to the present invention can completely separate glucose and sulfuric acid, and the acid tailing phenomenon is eliminated, showing excellent separation ability.

[0078] Comparative Example 1:

[0079] Using exactly the same experimental conditions as in Example 6, an experiment on separating a sugar-acid mixture (glucose, sulfuric acid) with a commercial strongly basic anion exchange resin A-853E (Duolite resin, manufacturer Beijing Kelsi Technology Co., Ltd.) and a strongly acidic cation exchange resin UBK-510L (Mitsubishi resin company, Japan) was carried out. The specific results are as follows:

[0080] When separating glucose and sulfuric acid with the strongly basic anion exchange resin A-853E, the recovery rate of sulfuric acid was 70%, and the purity of sulfuric acid was 100%; the recovery rate of glucose was 95%, and the purity of glucose was 100%.

[0081] Using strongly acidic cation exchange resin UBK-510L to separate glucose and sulfuric acid, the recovery rate of sulfuric acid is 98%, and the purity of sulfuric acid is 70%; the recovery rate of glucose is 95%, and the purity of glucose is 70%.

[0082] The chromatogram of sugar-acid separation is as Figure 3 and Figure 4 shown. It can be seen from Figure 3 that although baseline separation of glucose and sulfuric acid is achieved, the acid tailing phenomenon is very serious, and the elution of sulfuric acid is very slow. When eluting to 8.5 times the bed volume, the adsorbed acid is still not completely eluted. While for the PS-g-P(SBMA-DMC) resin provided by the present invention, when eluting to 4 times the bed volume, the sulfuric acid has been completely eluted.

[0083] It can be known from Figure 4 that although the sulfuric acid has been completely eluted at 2 times the bed volume without acid tailing, the peaks of sulfuric acid and glucose almost overlap, and the resolution is very low, resulting in very low purities of the recovered sulfuric acid and glucose.

[0084] It can be known from Figure 2 that the pseudo-strongly basic zwitterionic exchange resin of the present invention can not only eliminate the influence of acid tailing, but also achieve baseline separation of sulfuric acid and glucose. In terms of acid tailing, due to the elimination ability of the sulfonic acid group on the zwitterionic monomer SBMA, the tailing problem of sulfuric acid disappears. And through the Donnan effect of the quaternary ammonium groups on the zwitterionic monomer SBMA and the strongly basic monomer DMC, sulfuric acid is adsorbed on the medium while glucose is not adsorbed, thus achieving baseline separation of the two. Combining the two effects, compared with the two commercial resins A-853E and UBK-510L, the pseudo-strongly basic zwitterionic exchange resin of the present invention has excellent sugar-acid separation ability and acid tailing elimination ability.

[0085] Conclusion: The present invention provides a pseudo-strongly basic zwitterionic exchange resin for improving the acid tailing effect. This resin has excellent acid-sugar separation effect, can effectively improve the separation rate of acid and sugar, reduce the sulfuric acid tailing phenomenon while increasing the sulfuric acid recovery rate, and reduce the subsequent sulfuric acid concentration cost. This technology has broad application prospects, especially suitable for the separation and recovery of acid and sugar in the food and pharmaceutical fields, and can significantly improve the economic benefits of industrial separation processes.

[0086] The present invention provides an amphoteric ion exchange resin, a preparation method thereof, and an idea and method for application. There are many methods and ways to specifically implement this technical solution. The above description is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be realized by existing technologies.

Claims

1. A zwitterionic ion exchange resin, characterized in that The structural formula of the amphoteric ion exchange resin is as follows: in, PS stands for polystyrene microspheres; m is a positive number greater than 0; n is a positive number greater than 0; Among them, m unit structures and n unit structures Disordered aggregation.

2. The zwitterionic ion exchange resin according to claim 1, characterized in that The amphoteric ion exchange resin is obtained by introducing a monomer 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt and a monomer methacryloyloxyethyltrimethylammonium chloride into a chloromethylated polystyrene resin by using an atom transfer free radical polymerization reaction; The loading amount of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt in the amphoteric ion exchange resin is 0.2-2.0 mmol / g, and the loading amount of methacryloyloxyethyltrimethylammonium chloride is 0.1-1.5 mmol / g.

3. The method for preparing the zwitterionic ion exchange resin according to claim 1, characterized in that: The chloromethylated polystyrene resin is mixed with a solvent, soaked and swollen, and then 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, methacryloyloxyethyltrimethylammonium chloride, a base and a catalyst are added to carry out a grafting reaction to obtain a zwitterionic ion exchange resin.

4. The preparation method according to claim 1, characterized in that: The solvent is any one or a combination of water, N,N-dimethylformamide, toluene, ethanol and tetrahydrofuran; the base is any one or a combination of 2,2-bipyridine, triethylamine and pentamethyldiethylenetriamine; and the catalyst is any one or a combination of cuprous chloride, cuprous bromide and ferrous chloride.

5. The preparation method according to claim 1, characterized in that: The ratio of the mass amount of the chloromethylated polystyrene resin to the volume amount of the solvent is 2.5 g:40-70 mL.

6. The preparation method according to claim 1, characterized in that: The molar ratio of chlorine in the chloromethylated polystyrene resin to the 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt and methacryloyloxyethyltrimethylammonium chloride is 1:(20-50):(10-25); the mass ratio of the chloromethylated polystyrene resin to the alkali and the catalyst is (2.00-3.00):(1.25-1.60):(0.40-0.55).

7. The preparation method according to claim 1, characterized in that: The soaking and swelling process has a soaking time of 2 to 5 hours; the grafting reaction has a reaction temperature of 85° C. to 110° C. and a reaction time of 10 to 16 hours; and the grafting reaction is carried out under the protection of an inert gas.

8. Use of the amphoteric ion exchange resin according to claim 1 in separating sugar acids.

9. The use according to claim 8, characterized in that: The sugar is any one of glucose, xylose, arabinose and cellobiose or a combination of several thereof; the acid is any one of sulfuric acid, hydrochloric acid and phosphoric acid or a combination of several thereof.

10. The use according to claim 8, characterized in that: The amphoteric ion exchange resin has the function of reducing acid tailing in the process of separating sugar and acid.

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