Amphoteric ion exchange resin, its preparation method and application

Abstract

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

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of separation resin, and relates to a zwitterionic ion exchange resin and a preparation method and application thereof. BACKGROUND

[0002] The production of biofuels and bio-based chemicals from agricultural straw biomass as raw material can solve the problems of 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 is how to obtain fermentable sugar from raw materials. Concentrated acid hydrolysis can obtain fermentable sugar under normal pressure and mild conditions, which has the advantages of low energy consumption, low toxic by-products and no need for cellulase input. Sulfuric acid is the most commonly used. In order to reduce cost and environmental load, sulfuric acid must be recovered and reused, so sulfuric acid and sugar must be separated. Therefore, the separation of acid and sugar (such as sulfuric acid and glucose) is a crucial step. Traditional acid-sugar separation technology mostly uses ion exchange resin to complete the process.

[0003] However, the existing ion exchange resin has many problems: (1) poor separation degree: traditional cation exchange resin often accompanies poor separation degree in the process of separating acid and sugar, resulting in low purity of sulfuric acid and sugar, so that the separation efficiency is low. (2) Sulfuric acid tailing problem: traditional resin often accompanies sulfuric acid tailing phenomenon in the process of separating acid and sugar, resulting in low concentration of sulfuric acid recovery, affecting the subsequent processing process and increasing the concentration cost. (3) Low separation efficiency: due to the single structure of the existing resin, its separation efficiency is poor when facing different types of acid and sugar, which cannot meet the needs of efficient separation.

[0004] Therefore, a new type of acid-sugar separation resin is needed to overcome the above shortcomings, especially to maintain high separation efficiency and weaken or eliminate sulfuric acid tailing phenomenon, so as to improve the efficiency of acid-sugar separation and reduce the concentration cost. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a zwitterionic ion exchange resin and a preparation method and application thereof to solve the problems of the prior art.

[0006] The acid-sugar separation resin is prepared by polymerizing chloromethylated polystyrene resin with monomer 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt and monomer methacryloyloxyethyl trimethyl ammonium chloride through ATRP reaction, the loading amount of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt in the resin after the reaction is 0.2-2.0 mmol / g, and the loading amount of methacryloyloxyethyl trimethyl ammonium chloride is 0.1-1.5 mmol / g. The acid-sugar separation resin provided by the application is a novel strong alkaline zwitterionic exchange resin, when loading, the exposed quaternary ammonium salt groups of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt and methacryloyloxyethyl trimethyl ammonium chloride can improve the separation rate of acid and sugar; meanwhile, the sulfonate groups on 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt in the resin can effectively weaken the tailing phenomenon of sulfuric acid; the resin provided by the application has excellent acid-sugar separation effect, and sulfuric acid elution is easier, the acid tailing phenomenon is eliminated, so that the recovery efficiency of sulfuric acid is improved and the cost of subsequent sulfuric acid concentration is reduced.

[0007] To solve the above technical problems, the technical scheme adopted by the application is as follows:

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

[0009] ;

[0010] Among them,

[0011] PS represents polystyrene microspheres;

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

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

[0014] wherein, 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 zwitterion exchange resin is obtained by introducing the monomer 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt and the monomer methacryloyloxyethyltrimethylammonium chloride into chloromethylated polystyrene resin via atom transfer radical polymerization reaction.

[0018] The zwitterionic exchange resin has a loading of 0.2 to 2.0 mmol / g for the inner salt of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid and a loading of 0.1 to 1.5 mmol / g for the inner salt of methacryloyloxyethyltrimethylammonium chloride.

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

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

[0021] Furthermore, the present invention provides a method for preparing the above-mentioned zwitterionic exchange resin, wherein 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, base and catalyst are added to carry out a grafting reaction to obtain the zwitterionic exchange resin.

[0022] The chloromethylated polystyrene resin has a particle size of 3 μm to 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; and the catalyst is any one or a combination of several of cuprous chloride, cuprous bromide, and ferrous chloride.

[0024] In some embodiments, preferably, the solvent is any one or mixture of several of N,N-dimethylformamide, toluene, ethanol and tetrahydrofuran; further preferably, a mixture of water and N,N-dimethylformamide in any ratio; more preferably, a mixture of water and N,N-dimethylformamide in a volume ratio of 1: (2-4); most preferably, a mixture of water and N,N-dimethylformamide in 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 amount of the chloromethylated polystyrene resin to the volume amount of the solvent is 2.5 g: 40-70 mL.

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

[0029] In some embodiments, the molar ratio of the 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, methacryloyloxyethyltrimethylammonium chloride is 1: (20-50): (10-25); the mass ratio of the chloromethylated polystyrene resin to the base, catalyst is (2.00-3.00): (1.25-1.60): (0.40-0.55).

[0030] In some embodiments, preferably, the molar ratio of the 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, methacryloyloxyethyltrimethylammonium chloride is 1:30:15.

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

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

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

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

[0035] The use of the above-mentioned zwitterionic exchange resin in separating sugar acids is also within the protection scope of the present application.

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

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

[0038] Specifically, the zwitterionic exchange resin has the function of reducing acid tailing in the process of separating sugar acids.

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

[0040] Beneficial effects:

[0041] (1) The zwitterionic exchange resin provided by the present application can not only eliminate the influence of acid tailing, but also realize baseline separation of sulfuric acid and glucose. In terms of acid tailing, it is the elimination ability of the sulfonic acid group on the zwitterionic monomer SBMA that makes the tailing problem of sulfuric acid disappear. Then, the Donnan effect of the quaternary ammonium group on the zwitterionic monomer SBMA and the strongly alkaline monomer DMC makes sulfuric acid be adsorbed on the medium, and glucose is not adsorbed, so that the two are baseline separated.

[0042] (2) The zwitterionic exchange resin provided by the present application is used for separating sugar and acid, and the recovery rate of sulfuric acid can reach 100%, 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 application has excellent acid-sugar separation effect, and sulfuric acid elution is easier, acid tailing phenomenon is eliminated, and sugar acid is baseline separated, so as to improve the recovery efficiency of sulfuric acid and reduce the cost of subsequent sulfuric acid concentration. BRIEF DESCRIPTION OF DRAWINGS

[0044] The above and / or other aspects of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

[0045] Figure 1 Infrared spectrum of the PS-CH2-P(SBMA-DMC) resin prepared for Example 1~Example 4.

[0046] Figure 2 Sugar acid separation performance chart of the PS-CH2-P(SBMA-DMC) resin prepared for Example 2 of the present application.

[0047] Figure 3 Sugar acid separation performance chart of the commercial resin A-853E.

[0048] Figure 4 Sugar acid separation performance chart of the commercial resin UBK-510L. DETAILED DESCRIPTION

[0049] The present application can be better understood in accordance with the following examples. It will be readily apparent to those skilled in the art, however, that the

[0050] The experimental methods described in the following examples are routine methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

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

[0052] 2. The 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt (SBMA) used in the examples of the present application has a molecular formula of C 11 H 21 NO5S; and a molecular weight of 279.35.

[0053] 3. The methacryloyloxyethyl trimethyl ammonium chloride (DMC) used in the examples of the present application has a chemical formula of C9H 18 ClNO2; and a molecular weight of 207.698.

[0054] 4. The 2',2-dipyridyl (Bipy) used in the examples of the present application has a molecular weight of 156.19.

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

[0056] Example 1: Preparation of an acid sugar zwitterionic exchange resin

[0057] In a 250 mL three-necked flask (containing a stirring paddle), 2.5 g of 2 mmol / g of PS-Cl, 14 mL of H2O and 42 mL of DMF were soaked for 2 h; then 27.9 g of SBMA and 10.375 g of DMC were added to the three-necked flask (wherein the molar ratio of chlorine in PS-Cl to SBMA, DMC was 1:20:10), vacuumed, and nitrogen was introduced, which was repeated three times, then 1.56 g of Bipy and 0.495 g of CuCl were added, vacuumed, and nitrogen was introduced, which was repeated twice, the three-necked flask was placed in an oil bath at 110°C, and fixed nitrogen was introduced, and the grafting reaction was carried out for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice water bath, the remaining solution was removed by suction filtration, and then washed with DMF for 4-5 times, soaked in dilute hydrochloric acid for 0.5 h, washed with water and methanol for 3 times, and then dried at 40°C under vacuum to obtain 3.1 g of a pseudo-strongly basic zwitterionic exchange resin, which was recorded as PS-CH2-P(SBMA-DMC).

[0058] Example 2: Preparation of an acid-sugar zwitterionic exchange resin

[0059] In a 250 mL three-necked flask (containing a stirring paddle), 2.5 g of 2 mmol / g of PS-Cl, 14 mL of H2O and 42 mL of DMF were soaked for 2 h; then 27.9 g of SBMA and 10.375 g of DMC were added to the three-necked flask (wherein the molar ratio of chlorine in PS-Cl to SBMA, DMC was 1:20:10), vacuumed, and nitrogen was introduced, which was repeated three times, then 1.56 g of Bipy and 0.495 g of CuCl were added, vacuumed, and nitrogen was introduced, which was repeated twice, the three-necked flask was placed in an oil bath at 110°C, and fixed nitrogen was introduced, and the grafting reaction was carried out for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice water bath, the remaining solution was removed by suction filtration, and then washed with DMF for 4-5 times, soaked in dilute hydrochloric acid for 0.5 h, washed with water and methanol for 3 times, and then dried at 40°C under vacuum to obtain 3.1 g of a pseudo-strongly basic zwitterionic exchange resin, which was recorded as PS-CH2-P(SBMA-DMC).

[0060] Example 3: Preparation of an acid-sugar zwitterionic exchange resin

[0061] A 250 mL three-neck flask (containing a stirring paddle) was charged with 2.5 g of 2 mmol / g PS-Cl, 14 mL of H2O and 42 mL of DMF and soaked for 2 h; 55.8 g of SBMA and 20.75 g of DMC were then added to the three-neck flask (wherein the molar ratio of chlorine in PS-Cl to SBMA, DMC was 1:40:20), vacuumed, and purged with nitrogen three times, followed by the addition of 1.56 g of Bipy and 0.495 g of CuCl, vacuumed, and purged with nitrogen two times, and the three-neck flask was placed in an oil bath at 110°C, purged with fixed nitrogen, and subjected to grafting reaction for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice-water bath, vacuum filtration was performed to remove the remaining solution, and the product was washed with DMF for 4-5 times, soaked in dilute hydrochloric acid for 0.5 h, washed with water and methanol for 3 times, and vacuum dried at 40°C to obtain 3.5 g of pseudo-strongly basic zwitterionic exchange resin, which was recorded as PS-CH2-P(SBMA-DMC).

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

[0063] A 250 mL three-neck flask (containing a stirring paddle) was charged with 2.5 g of 2 mmol / g PS-Cl, 14 mL of H2O and 42 mL of DMF and soaked for 2 h; 55.8 g of SBMA and 20.75 g of DMC were then added to the three-neck flask (wherein the molar ratio of chlorine in PS-Cl to SBMA, DMC was 1:40:20), vacuumed, and purged with nitrogen three times, followed by the addition of 1.56 g of Bipy and 0.495 g of CuCl, vacuumed, and purged with nitrogen two times, and the three-neck flask was placed in an oil bath at 110°C, purged with fixed nitrogen, and subjected to grafting reaction for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature in an ice-water bath, vacuum filtration was performed to remove the remaining solution, and the product was washed with DMF for 4-5 times, soaked in dilute hydrochloric acid for 0.5 h, washed with water and methanol for 3 times, and vacuum dried at 40°C to obtain 3.5 g of pseudo-strongly basic zwitterionic exchange resin, which was recorded as PS-CH2-P(SBMA-DMC).

[0064] Example 5:

[0065] (1) The PS-CH2-P(SBMA-DMC) prepared in Examples 1-4 was subjected to infrared detection, respectively, and the results were as follows: Figure 1The figure shows: the line a: PS-CH2-P(SBMA-DMC) (the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:20:10); the line b: PS-CH2-P(SBMA-DMC) (the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:30:15); the line c: PS-CH2-P(SBMA-DMC) (the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:40:20); the line d: PS-CH2-P(SBMA-DMC) (the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:50:25); and the line e: PS-Cl.

[0066] As can be seen from the figure, the hydrophilic medium PS-CH2-P(SBMA-DMC) has a peak at 1535 cm -1 corresponding to the vibration of C-N, 1720 cm -1 corresponding to the vibration of C=O in the ester group, 1191 cm -1 and 1036 cm -1 corresponding to the anti-symmetric vibration and symmetric vibration of S=O respectively, indicating that the hydrophilic medium PS-CH2-P(SBMA-DMC) is successfully synthesized.

[0067] (2) The loading of the product (PS-CH2-P(SBMA-DMC) prepared in Examples 1-4) is calculated according to the following formula, which is shown in Table 1:

[0068] Quaternary ammonium group: LA1 = [(W2-W1) / (279+207.5)] / W1;

[0069] Sulfonic acid group: LA2 = 2*LA1 / 3;

[0070] In the above formula, W1 and W2 are the mass of the resin before and after the reaction respectively; wherein 279 is the relative molecular mass of SBMA and 207.5 is the relative molecular mass of DMC.

[0071] Table 1

[0072] Example 1 Example 2 Example 3 Example 4 Molar ratio of chlorine in the resin to monomer SBMA, monomer DMC 1：20：10 1：30：15 1：40：20 1：50：25 Reaction temperature / °C 110 110 110 110 Reaction time / h 12 12 12 12 PS-Cl resin addition amount / g 2.5 2.5 2.5 2.5 Mass of the zwitterionic exchange resin / g 3.1 4.2 3.5 3.3 Loading LA1 (mmol / g) 0.493 1.398 0.822 0.658 Loading LA2 (mmol / g) 0.329 0.932 0.548 0.439

[0073] In summary, from the above table, it can be seen that when the molar ratio of chlorine in PS-Cl resin to monomer SBMA and monomer DMC is 1:30:15, the loading of quaternary ammonium group and sulfonic acid group is the largest; in addition, according to the infrared spectrum Figure 1 It can be determined that monomer SBMA and monomer DMC are successfully grafted onto PS-Cl resin. Therefore, combining these two results, it is determined that the optimal condition of the reaction is that the molar ratio of chlorine in the resin to monomer SBMA and monomer 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 sulfuric acid / glucose mixture.

[0075] Example 6:

[0076] In this example, 7 g or so of zwitterionic exchange resin PS-g-P(SBMA-DMC) prepared in Example 2 (wherein the molar ratio of chlorine in PS-Cl to SBMA and DMC is 1:30:15 at the time of feeding) was packed into a glass column with a specification (inner diameter 1 cm, height 17 cm), then converted with 100 mL of 1 mol / L sulfuric acid, and finally washed with water to remove the sulfuric acid. The sample solution (a mixture of water, sulfuric acid, and glucose) had 40 g / L of sulfuric acid and 130 g / L of glucose, and the solvent was water, with a sample amount of 4 mL. Then, pure water was used for elution until complete (no acid at the bottom of the column). 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] The high-performance liquid chromatography differential refractive index detection method was used, with 5 mmol / L sulfuric acid as the mobile phase, a detection temperature of 55°C, and a flow rate of 0.6 mL / min. The chromatogram is shown in Figure 2 As can be seen from Figure 2 , the R (resolution) of the adjacent two components is ≥1.5. The chromatographic column packed with PS-g-P(SBMA-DMC) of the present application can completely separate glucose and sulfuric acid, and the acid tailing phenomenon is eliminated, showing excellent separation capacity.

[0078] Comparative Example 1:

[0079] The same experimental conditions as in Example 6 were used to separate the sugar acid mixture (glucose, sulfuric acid) with the commercial strongly basic anion exchange resin A-853E (Duosorb resin, manufacturer Beijing Kehaisisheng Technology Co., Ltd.) and the strongly acidic cation exchange resin UBK-510L (Mitsubishi Resin Co., Ltd., Japan). The specific results are as follows:

[0080] 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] With the strongly acidic cation exchange resin UBK-510L, the recovery rate of sulfuric acid was 98%, and the purity of sulfuric acid was 70%. The recovery rate of glucose was 95%, and the purity of glucose was 70%.

[0082] The sugar acid separation chromatogram is asFigure 3 and Figure 4 It can be seen from the figure that, although glucose and sulfuric acid achieve baseline separation, acid tailing is very serious, and sulfuric acid elutes very slowly, and the adsorbed acid is not completely eluted until elution to 8.5 times the bed volume. Figure 3 It can be seen from the figure that, although glucose and sulfuric acid achieve baseline separation, acid tailing is very serious, and sulfuric acid elutes very slowly, and the adsorbed acid is not completely eluted until elution to 8.5 times the bed volume.

[0083] Figure 4 It can be seen from the figure that, although glucose and sulfuric acid achieve baseline separation, acid tailing is very serious, and sulfuric acid elutes very slowly, and the adsorbed acid is not completely eluted until elution to 8.5 times the bed volume.

[0084] It can be seen from the figure that, although glucose and sulfuric acid achieve baseline separation, acid tailing is very serious, and sulfuric acid elutes very slowly, and the adsorbed acid is not completely eluted until elution to 8.5 times the bed volume. Figure 2 It can be seen from the figure that, although glucose and sulfuric acid achieve baseline separation, acid tailing is very serious, and sulfuric acid elutes very slowly, and the adsorbed acid is not completely eluted until elution to 8.5 times the bed volume.

[0085] Conclusion: The pseudo-strongly basic zwitterionic ion exchange resin provided by the present application has excellent acid-sugar separation effect, can effectively improve the separation rate of acid and sugar, and can improve the recovery rate of sulfuric acid while reducing the acid tailing phenomenon of sulfuric acid, thereby reducing the cost of subsequent sulfuric acid concentration. The technology has wide application prospect, and is especially suitable for the separation and recovery of acid and sugar in the fields of food and medicine, and can significantly improve the economic benefit of the industrial separation process.

[0086] The present application provides a zwitterionic ion exchange resin, a preparation method and application thereof, and ideas and methods for implementing the technical solution. The above description is only a preferred embodiment of the present application, and it should be pointed out that, for ordinary skilled persons in the technical field, without departing from the principle of the present application, a number of improvements and refinements can be made, which should also be regarded as the protection scope of the present application. The components not explicitly described in the embodiment can be realized by existing technology.​

Claims

1. A zwitterionic exchange resin, characterized in that, The structural formula of the zwitterionic ion exchange resin is shown below: ； 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 Disorderly aggregation.

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

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

4. The preparation method according to claim 3, characterized in that, 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; and the catalyst is any one or a combination of several of cuprous chloride, cuprous bromide, and ferrous chloride.

5. The preparation method according to claim 3, characterized in that, The ratio of the mass of the chloromethylated polystyrene resin to the volume of the solvent is 2.5 g: 40~70 mL.

6. The preparation method according to claim 3, 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 catalyst is (2.00~3.00):(1.25~1.60):(0.40~0.55).

7. The preparation method according to claim 3, characterized in that, The soaking and swelling process takes 2-5 hours; the grafting reaction takes 85℃-110℃ for 10-16 hours; and the grafting reaction is carried out under inert gas protection.

8. The application of the zwitterionic exchange resin according to claim 1 in the separation of sugars and acids.

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

10. The application according to claim 8, characterized in that, The aforementioned zwitterionic exchange resin has the function of reducing acid tailing during the separation of sugar and acid.

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