A method for extracting vitamin C from vitamin C mother solution

Abstract

The invention provides a method for extracting vitamin C from a vitamin C mother liquor, belonging to the technical field of vitamin C; the method comprises the steps of salting, separation, preparing a macroporous exchange resin, and ion exchange; the step of preparing the macroporous exchange resin comprises the steps of preparing a resin matrix, sulfonation, preparing a resin matrix auxiliary agent, and mixing; the step of preparing the resin matrix auxiliary agent comprises the steps of placing silicon dioxide in a closed container, adding an ethanol solution and stirring evenly, then adding sodium oleate and glyceryl monostearate, stirring evenly and subjecting to microwave irradiation, while subjecting to microwave irradiation and subjecting to ball milling, filtering and drying to obtain a primary auxiliary agent; the primary auxiliary agent is added into an ethanol solution and stirred, after stirring evenly, 3-aminopropyltriethoxysilane is added, the temperature is increased to 65-69° C., stirring for 3.8-4.3 hours, filtering, washing, and drying after the stirring is completed, to obtain a resin matrix auxiliary agent; the vitamin C extracted by the method has high purity and yield, and the recovery and regeneration performance of the macroporous exchange resin is good.

Description

Technical Field

[0001] The invention belongs to the technical field of vitamin C, and in particular relates to a method for extracting vitamin C from a vitamin C mother solution. Background Art

[0002] Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin that can effectively prevent arteriosclerosis, treat anemia, treat scurvy, and enhance human immunity. It is currently the world's largest vitamin product with the widest production and sales volume and the widest range of applications.

[0003] At present, a two-step fermentation method is usually adopted for the preparation of vitamin C, specifically, D-glucose, L-sorbitol and other microorganisms are fermented to obtain gulonic acid, gulonic acid is chemically converted to obtain vitamin C liquid, and the vitamin C liquid is subjected to ultrafiltration to remove impurities, ion exchange transformation, nanofiltration concentration and crystallization to obtain the vitamin C product; however, the crystallization liquid, i.e., the vitamin C mother liquor, still contains a large amount of vitamin C and gulonic acid and other ingredients, and the components interfere with each other and cannot be crystallized. If the vitamin C mother liquor is discharged directly, it will not only increase the production cost, but also cause greater pollution to the environment.

[0004] Therefore, providing a method for extracting vitamin C from vitamin C mother solution has important economic value and environmental significance.

[0005] CN101041649A discloses a production method for recovering vitamin C and gulonic acid from vitamin C mother liquor, which specifically comprises the following steps: pumping the diluted vitamin C mother liquor into an adsorption column filled with anion exchange resin, washing the adsorption column with water after adsorption, collecting the effluent, concentrating and crystallizing the effluent through nanofiltration, and recrystallizing the effluent to obtain vitamin C crystals; desorbing the adsorbed anion exchange resin through elution with dilute sulfuric acid, and recovering the gulonic acid in the desorbed liquid;

[0006] This method uses a large amount of filler in the column, is intermittently operated, is time-consuming, and the purity of the extracted vitamin C is low.

[0007] CN112876437A discloses a method for extracting vitamin C using a macroporous chelating resin, which includes preparing the macroporous chelating resin and purifying vitamin C. When preparing the macroporous chelating resin, p-phenolsulfonic acid and styrene are used as polymer chain structure base materials, and resin slurry is generated in the presence of a resorcinol copolymer cross-linking agent; a suspension polymerization reaction is carried out by adding a divinylbenzene polycondensation cross-linking agent to prepare a polymer spherical resin, and gulonic acid is added as a porogen inside the resin in the later stage of the reaction to generate a resin; and then a chromatographic separation system composed of chromatographic columns is used to purify the vitamin C.

[0008] This method makes the separation of components between vitamin C and citric acid more obvious, and improves the extraction efficiency of vitamin C. However, the macroporous chelating resin produced by this patent has poor regeneration ability. When it is recycled again, the extraction efficiency of vitamin C is significantly reduced. Summary of the invention

[0009] In order to solve the technical problems existing in the prior art, the present invention provides a method for extracting vitamin C from a vitamin C mother liquor, which adopts a macroporous functional resin for extraction, has high extraction efficiency, and the extracted vitamin C has high purity. In addition, the macroporous functional resin has strong regeneration ability and good recycling performance.

[0010] In view of the above technical problems, the present invention adopts the following technical solutions:

[0011] A method for extracting vitamin C from a vitamin C mother solution comprises the following steps:

[0012] 1. Salt formation

[0013] The vitamin C mother solution is heated to 51-55°C at a rate of 1.8-2.2°C / min, a sodium hydroxide solution is added, the pH is controlled to be 6.0-6.4, and ultrasonic treatment is performed. The ultrasonic time is 14-18 minutes, the ultrasonic power is 80-85W, and the ultrasonic frequency is 27-32kHz. After the ultrasonic treatment, the temperature is raised to 58-62°C at a rate of 0.4-0.6°C / min, activated clay is added, and stirred for 11-15 minutes. After the stirring is completed, the mixed salt solution is obtained after filtering;

[0014] The mass concentration of the sodium hydroxide solution is 48-52%;

[0015] The particle size of the activated clay is 230-250nm;

[0016] The mass volume ratio of the vitamin C mother solution and the white clay is 180-220 mL:1.0-1.4 g.

[0017] 2. Separation

[0018] The mixed salt solution is concentrated at a concentration temperature of 65-69°C to 0.47-0.50 times the volume of the mixed salt solution, and then the temperature is reduced to 14-16°C at a rate of 0.8-1.2°C / min, and stirred at 14-16°C for 6.0-6.4h with a stirring speed of 104-115rpm. After the stirring is completed, gulonic acid salt is precipitated, leaving the separated vitamin C mother liquor.

[0019] 3. Preparation of Macroporous Exchange Resin

[0020] (1) Preparation of resin matrix

[0021] Add polyvinyl alcohol, sodium dodecylbenzene sulfonate and Tween 80 to deionized water, stir at a temperature of 52-55°C, and after stirring evenly, naturally cool to room temperature to obtain a mixed solution 1; add styrene, dipropylene benzene and benzoyl peroxide to a reaction container for ultrasonic treatment, the ultrasonic time is 32-36 minutes, the ultrasonic power is 73-78W, and the ultrasonic frequency is 30-34kHz. After the ultrasonic treatment is completed, add paraffin and stir evenly to obtain a mixed solution 2;

[0022] Add mixed solution 2 to mixed solution 1, stir evenly, heat to 71-75°C at a rate of 2.7-3.2°C / min, stir for 3.0-3.4h, stir at a speed of 164-175rpm, then heat to 94-98°C at a rate of 1.2-1.4°C / min, stir for 3.8-4.2h, stir at a speed of 117-124rpm, and naturally cool to room temperature after the stirring reaction is completed, wash, and dry at 66-70°C for 4.7-5.0h to obtain a resin matrix;

[0023] In the mixed solution 1, the mass ratio of the deionized water, polyvinyl alcohol, sodium dodecylbenzene sulfonate and Tween 80 is 146-153:0.41-0.45:0.12-0.16:0.25-0.27;

[0024] In the second mixed solution, the mass ratio of styrene, dipropylene benzene, benzoyl peroxide and paraffin is 16.6-17.0:1.8-2.2:0.18-0.22:2.2-2.4;

[0025] The mass ratio of the mixed solution 1 to the mixed solution 2 is 7.48-7.53:2.84-2.88;

[0026] (2) Sulfonation

[0027] The resin matrix is ​​placed in a reaction container, sulfuric acid solution is introduced, and the temperature is raised to 92-96°C at 223-235 rpm, and stirred at 92-96°C for 2.4-2.6 hours. After the stirring is completed, the temperature is further raised to 120-125°C, and the temperature is kept and stirred for 4.4-4.6 hours. After the stirring is completed, the temperature is naturally lowered to room temperature, and the sulfonated resin is washed, filtered, and dried to obtain the sulfonated resin;

[0028] The mass concentration of the sulfuric acid solution is 88-92%;

[0029] The mass ratio of the resin matrix to the sulfuric acid solution is 6.3-6.7:24.5-25.0;

[0030] (3) Preparation of resin matrix additives

[0031] The silicon dioxide is placed in a sealed container, and an ethanol solution is added and stirred evenly. Then, sodium oleate and glyceryl monostearate are added, and the mixture is stirred evenly and then microwave irradiated. The irradiation time is 10-14 minutes, the irradiation power is 514-525W, and the irradiation temperature is 107-112°C. Ball milling is performed while microwave irradiation. The ball milling speed is 205-215rpm, and the ball-to-material ratio is 5-7:1. After the microwave irradiation is completed, the primary auxiliary agent is obtained after filtering and drying. The primary auxiliary agent is added into the ethanol solution and stirred. After stirring evenly, 3-aminopropyltriethoxysilane is added, the temperature is increased to 65-69°C, and the mixture is stirred for 3.8-4.3 hours. After the stirring is completed, the mixture is filtered, washed, and dried to obtain a resin matrix auxiliary agent.

[0032] The particle size of the silicon dioxide is 275-285 nm;

[0033] The mass concentration of the ethanol solution is 43-47%;

[0034] The mass ratio of the silicon dioxide, ethanol solution, sodium oleate and glyceryl monostearate is 10.3-10.7:90-95:0.7-0.9:0.2-0.4;

[0035] The mass ratio of the primary auxiliary agent, the ethanol solution, and 3-aminopropyltriethoxysilane is 6.5-6.9:82-87:0.62-0.66;

[0036] (4) Mixing

[0037] The sulfonated resin is placed in a sealed container, deionized water is added, the temperature is raised to 84-88°C, and a resin matrix additive is added. After the addition is completed, stirring is performed at a stirring speed of 135-145 rpm for 58-62 minutes. After the stirring is completed, filtering and drying are performed to obtain a macroporous exchange resin;

[0038] The mass ratio of the sulfonated resin, deionized water, and resin matrix additive is 5.6-6.0 g:98-104 mL:1.3-1.5 g.

[0039] 4. Ion Exchange

[0040] The separated vitamin C mother liquor is pumped into a macroporous exchange resin column for impurity removal at a flow rate of 1 BV / h and a resin column volume of 1000 mL. After three cycles, components with a pH value lower than 1.6-1.8 are collected to obtain a vitamin C extracted solution, which is concentrated and crystallized to obtain vitamin C.

[0041] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0042] 1. The present invention first prepares a resin matrix, then performs sulfonation, so that the surface of the resin matrix contains more sulfonic acid groups, and then uses silicon dioxide to prepare a resin matrix auxiliary agent. After the silicon dioxide is dispersed with sodium oleate and glyceryl monostearate, microwave irradiation is performed, so that more lattice defects and distortions are generated on the surface of the silicon dioxide, thereby increasing the specific surface area of ​​the silicon dioxide and thus increasing the contact area with the feed liquid. In addition, the silicon dioxide is treated with aminosilane, so that amino groups are grafted on the surface of the silicon dioxide, so that the silicon dioxide and the resin matrix can be better connected, the binding force is good, and the stability is good. The surface of the silicon dioxide carries more negative charges, which can be balanced by cations. Therefore, the prepared resin matrix auxiliary agent has good adsorption performance. It is combined with the resin matrix to enhance the adsorption performance and ion exchange performance of the macroporous exchange resin, improve the stability performance, and after multiple recycling and regeneration, it still has good ion exchange performance, has a good extraction effect on vitamin C, and the prepared vitamin C product has a high purity and yield;

[0043] 2. The vitamin C extracted by the method of the present invention has a purity of 95.34-96.12% and a yield of 86.1-86.7%;

[0044] 3. The purity of vitamin C extracted from the macroporous exchange resin prepared by the method of the present invention is 92.86-94.69% and the yield is 83.1-84.4% at the 30th recycling and regeneration. DETAILED DESCRIPTION

[0045] In order to more clearly understand the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described.

[0046] Example 1

[0047] 1. Salt formation

[0048] 200 mL of vitamin C mother solution was heated to 53° C. at a rate of 2.0° C. / min, sodium hydroxide solution was added, the pH was controlled to be 6.2, and ultrasonic treatment was performed. The ultrasonic time was 16 min, the ultrasonic power was 83 W, and the ultrasonic frequency was 29 kHz. After the ultrasonic treatment, the temperature was raised to 60° C. at a rate of 0.5° C. / min, 1.2 g of activated clay was added, and the mixture was stirred for 13 min. After the stirring was completed, the mixture was filtered to obtain a mixed salt solution.

[0049] The mass concentration of the sodium hydroxide solution is 50%;

[0050] The particle size of the activated clay is 240 nm.

[0051] 2. Separation

[0052] The mixed salt solution was concentrated at a concentration temperature of 67°C to 0.48 times the volume of the mixed salt solution, and then the temperature was reduced to 15°C at a rate of 1.0°C / min. Stirring was carried out at 15°C for 6.2 hours with a stirring speed of 110 rpm. After the stirring was completed, gulonic acid salt was precipitated, leaving the separated vitamin C mother liquor.

[0053] 3. Preparation of Macroporous Exchange Resin

[0054] (1) Preparation of resin matrix

[0055] 0.43 g of polyvinyl alcohol, 0.14 g of sodium dodecylbenzene sulfonate and 0.26 g of Tween 80 were added to 150 g of deionized water, and the mixture was stirred at a temperature of 54° C. After being stirred evenly, the mixture was naturally cooled to room temperature to obtain a mixed solution 1.

[0056] 16.8 g of styrene, 2.0 g of dipropylene benzene and 0.20 g of benzoyl peroxide were added to the reaction container for ultrasonic treatment. The ultrasonic treatment time was 34 min, the ultrasonic power was 75 W, and the ultrasonic frequency was 32 kHz. After the ultrasonic treatment, 2.3 g of paraffin was added and stirred to obtain a mixed solution II.

[0057] Add 2.86 g of mixed solution 2 to 7.51 g of mixed solution 1, stir evenly, heat to 73 ° C at a rate of 3.0 ° C / min, stir for 3.2 h, stir at 170 rpm, then heat to 96 ° C at a rate of 1.3 ° C / min, stir for 4.0 h, stir at 120 rpm, and naturally cool to room temperature after the stirring reaction. After washing, dry at 68 ° C for 4.8 h to obtain a resin matrix;

[0058] (2) Sulfonation

[0059] 6.5 g of the resin matrix was placed in a reaction container, and 24.7 g of sulfuric acid solution was introduced. The temperature was raised to 94° C. at 230 rpm, and stirred at 94° C. for 2.5 h. After the stirring was completed, the temperature was further raised to 122° C. and kept stirring for 4.5 h. After the stirring was completed, the temperature was naturally lowered to room temperature, and the sulfonated resin was obtained by washing, filtering, and drying.

[0060] The mass concentration of the sulfuric acid solution is 90%;

[0061] (3) Preparation of resin matrix additives

[0062] 10.5 g of silicon dioxide was placed in a sealed container, 92 g of ethanol solution was added and stirred evenly, then 0.8 g of sodium oleate and 0.3 g of glyceryl monostearate were added, and microwave irradiation was performed after stirring evenly. The irradiation time was 12 min, the irradiation power was 520 W, and the irradiation temperature was 110° C. Ball milling was performed while microwave irradiation. The ball milling speed was 210 rpm and the ball-to-material ratio was 6:1. After the microwave irradiation, the primary auxiliary agent was obtained after filtering and drying. 6.7 g of the primary auxiliary agent was added into 84 g of ethanol solution and stirred. After stirring evenly, 0.64 g of 3-aminopropyltriethoxysilane was added, the temperature was raised to 67° C., and stirred for 4.0 h. After the stirring was completed, the resin matrix auxiliary agent was obtained after filtering, washing, and drying.

[0063] The particle size of the silicon dioxide is 280 nm;

[0064] The mass concentration of the ethanol solution is 45%;

[0065] (4) Mixing

[0066] Place 5.8 g of sulfonated resin in a sealed container, add 100 mL of deionized water, raise the temperature to 86°C, add 1.4 g of resin matrix additive, and after the addition is completed, stir at a stirring speed of 140 rpm for 60 min. After the stirring is completed, filter and dry to obtain a macroporous exchange resin.

[0067] 4. Ion Exchange

[0068] The separated vitamin C mother liquor is pumped into a macroporous exchange resin column for impurity removal at a flow rate of 1 BV / h and a resin column volume of 1000 mL. After three cycles, components with a pH value lower than 1.7 are collected to obtain a vitamin C extracted solution, which is concentrated and crystallized to obtain vitamin C.

[0069] The vitamin C mother solution used in Example 1 has a vitamin C content of 127.4 g / L and a gulonic acid content of 156.8 g / L;

[0070] The vitamin C prepared by the method of Example 1 has a purity of 96.12% and a yield of 86.7%.

[0071] Example 2

[0072] 1. Salt formation

[0073] 180 mL of vitamin C mother solution was heated to 51° C. at a rate of 1.8° C. / min, sodium hydroxide solution was added, the pH was controlled to be 6.0, and ultrasonic treatment was performed. The ultrasonic time was 14 min, the ultrasonic power was 80 W, and the ultrasonic frequency was 27 kHz. After the ultrasonic treatment, the temperature was raised to 58° C. at a rate of 0.4° C. / min, 1.0 g of activated clay was added, and the mixture was stirred for 11 min. After the stirring was completed, the mixture was filtered to obtain a mixed salt solution.

[0074] The mass concentration of the sodium hydroxide solution is 48%;

[0075] The particle size of the activated clay is 230 nm.

[0076] 2. Separation

[0077] The mixed salt solution was concentrated at a concentration temperature of 65°C to 0.47 times the volume of the mixed salt solution, and then the temperature was reduced to 14°C at a rate of 0.8°C / min. Stirring was carried out at 14°C for 6.0h with a stirring speed of 104rpm. After the stirring was completed, gulonic acid salt was precipitated, leaving the separated vitamin C mother liquor.

[0078] 3. Preparation of Macroporous Exchange Resin

[0079] (1) Preparation of resin matrix

[0080] 0.41 g of polyvinyl alcohol, 0.12 g of sodium dodecylbenzene sulfonate and 0.25 g of Tween 80 were added to 146 g of deionized water, and the mixture was stirred at a temperature of 52° C. After being stirred evenly, the mixture was naturally cooled to room temperature to obtain a mixed solution 1.

[0081] 16.6 g of styrene, 1.8 g of dipropylene benzene and 0.18 g of benzoyl peroxide were added to the reaction container for ultrasonic treatment. The ultrasonic treatment time was 32 min, the ultrasonic power was 73 W, and the ultrasonic frequency was 30 kHz. After the ultrasonic treatment, 2.2 g of paraffin was added and stirred to obtain a mixed solution II.

[0082] 2.84 g of mixed solution 2 was added to 7.48 g of mixed solution 1, and after being stirred evenly, the temperature was raised to 71° C. at a rate of 2.7° C. / min, and the reaction was stirred for 3.0 h at a stirring speed of 164 rpm. The temperature was then raised to 94° C. at a rate of 1.2° C. / min, and the reaction was stirred for 3.8 h at a stirring speed of 117 rpm. After the stirring reaction was completed, the temperature was naturally lowered to room temperature, and after washing, it was dried at 66° C. for 4.7 h to obtain a resin matrix;

[0083] (2) Sulfonation

[0084] 6.3 g of resin matrix was placed in a reaction container, 24.5 g of sulfuric acid solution was introduced, and the temperature was raised to 92° C. at 223 rpm, and stirred at 92° C. for 2.4 h. After the stirring was completed, the temperature was further raised to 120° C. and kept stirring for 4.4 h. After the stirring was completed, the temperature was naturally lowered to room temperature, washed, filtered, and dried to obtain a sulfonated resin;

[0085] The mass concentration of the sulfuric acid solution is 88%;

[0086] (3) Preparation of resin matrix additives

[0087] 10.3 g of silicon dioxide was placed in a sealed container, 90 g of ethanol solution was added and stirred evenly, then 0.7 g of sodium oleate and 0.2 g of glyceryl monostearate were added, and microwave irradiation was performed after stirring evenly. The irradiation time was 10 min, the irradiation power was 514 W, and the irradiation temperature was 107 ° C. Ball milling was performed while microwave irradiation. The ball milling speed was 205 rpm and the ball-to-material ratio was 5:1. After the microwave irradiation, the primary auxiliary agent was obtained after filtering and drying; 6.5 g of the primary auxiliary agent was put into 82 g of ethanol solution and stirred. After stirring evenly, 0.62 g of 3-aminopropyltriethoxysilane was added, the temperature was raised to 65 ° C, and stirred for 3.8 h. After the stirring was completed, the resin matrix auxiliary agent was obtained after filtering, washing, and drying.

[0088] The particle size of the silicon dioxide is 275 nm;

[0089] The mass concentration of the ethanol solution is 43%;

[0090] (4) Mixing

[0091] Place 5.6 g of sulfonated resin in a sealed container, add 98 mL of deionized water, raise the temperature to 84°C, add 1.3 g of resin matrix additive, and after the addition is completed, stir at a stirring speed of 135 rpm for 58 min. After the stirring is completed, filter and dry to obtain a macroporous exchange resin.

[0092] 4. Ion Exchange

[0093] The separated vitamin C mother liquor is pumped into a macroporous exchange resin column for impurity removal at a flow rate of 1 BV / h and a resin column volume of 1000 mL. After three cycles, components with a pH value lower than 1.6 are collected to obtain a vitamin C produced solution, which is concentrated and crystallized to obtain vitamin C.

[0094] The vitamin C mother solution used in Example 2 has a vitamin C content of 127.4 g / L and a gulonic acid content of 156.8 g / L;

[0095] The vitamin C prepared by the method of Example 2 has a purity of 95.34% and a yield of 86.1%.

[0096] Example 3

[0097] 1. Salt formation

[0098] 220 mL of vitamin C mother solution was heated to 55° C. at a rate of 2.2° C. / min, sodium hydroxide solution was added, the pH was controlled to be 6.4, and ultrasonic treatment was performed. The ultrasonic time was 18 min, the ultrasonic power was 85 W, and the ultrasonic frequency was 32 kHz. After the ultrasonic treatment, the temperature was raised to 62° C. at a rate of 0.6° C. / min, 1.4 g of activated clay was added, and the mixture was stirred for 15 min. After the stirring was completed, the mixture was filtered to obtain a mixed salt solution.

[0099] The mass concentration of the sodium hydroxide solution is 52%;

[0100] The particle size of the activated clay is 250 nm.

[0101] 2. Separation

[0102] The mixed salt solution was concentrated at a concentration temperature of 69°C to 0.50 times the volume of the mixed salt solution, and then the temperature was reduced to 16°C at a rate of 1.2°C / min. Stirring was carried out at 16°C for 6.4 hours at a stirring speed of 115 rpm. After the stirring was completed, gulonic acid salt was precipitated, leaving the separated vitamin C mother liquor.

[0103] 3. Preparation of Macroporous Exchange Resin

[0104] (1) Preparation of resin matrix

[0105] 0.45 g of polyvinyl alcohol, 0.16 g of sodium dodecylbenzene sulfonate and 0.27 g of Tween 80 were added to 153 g of deionized water, and the mixture was stirred at a temperature of 55° C. After being stirred evenly, the mixture was naturally cooled to room temperature to obtain a mixed solution 1;

[0106] 17.0 g of styrene, 2.2 g of dipropylene benzene and 0.228 g of benzoyl peroxide were added to the reaction container for ultrasonic treatment. The ultrasonic treatment time was 36 min, the ultrasonic power was 8 W, and the ultrasonic frequency was 34 kHz. After the ultrasonic treatment, 2.4 g of paraffin was added and stirred to obtain a mixed solution II.

[0107] 2.88 g of mixed solution 2 was added to 7.53 g of mixed solution 1, and after being stirred evenly, the temperature was raised to 75° C. at a rate of 3.27° C. / min, and the reaction was stirred for 3.4 h at a stirring speed of 175 rpm. The temperature was then raised to 98° C. at a rate of 1.4° C. / min, and the reaction was stirred for 4.2 h at a stirring speed of 124 rpm. After the stirring reaction was completed, the temperature was naturally lowered to room temperature, and after washing, it was dried at 70° C. for 5.0 h to obtain a resin matrix;

[0108] (2) Sulfonation

[0109] 6.7 g of resin matrix was placed in a reaction container, and 25.0 g of sulfuric acid solution was introduced. The temperature was raised to 96° C. at 235 rpm, and stirred at 96° C. for 2.6 h. After the stirring was completed, the temperature was further raised to 125° C. and kept stirring for 4.6 h. After the stirring was completed, the temperature was naturally lowered to room temperature, and the sulfonated resin was obtained by washing, filtering, and drying.

[0110] The mass concentration of the sulfuric acid solution is 92%;

[0111] (3) Preparation of resin matrix additives

[0112] 10.7g of silicon dioxide was placed in a sealed container, 95g of ethanol solution was added and stirred evenly, then 0.9g of sodium oleate and 0.4g of glyceryl monostearate were added, and microwave irradiation was performed after stirring evenly. The irradiation time was 14min, the irradiation power was 525W, and the irradiation temperature was 112°C. Ball milling was performed while microwave irradiation. The ball milling speed was 215rpm, and the ball-to-material ratio was 7:1. After the microwave irradiation, the primary auxiliary agent was obtained after filtering and drying; 6.9g of the primary auxiliary agent was put into 87g of ethanol solution and stirred. After stirring evenly, 0.66g of 3-aminopropyltriethoxysilane was added, the temperature was raised to 69°C, and stirred for 4.3h. After the stirring was completed, the resin matrix auxiliary agent was obtained after filtering, washing, and drying.

[0113] The particle size of the silicon dioxide is 285 nm;

[0114] The mass concentration of the ethanol solution is 47%;

[0115] (4) Mixing

[0116] Place 6.0 g of sulfonated resin in a sealed container, add 104 mL of deionized water, raise the temperature to 88°C, add 1.5 g of resin matrix additive, and after the addition is completed, stir at a stirring speed of 145 rpm for 62 min. After the stirring is completed, filter and dry to obtain a macroporous exchange resin.

[0117] 4. Ion Exchange

[0118] The separated vitamin C mother liquor is pumped into a macroporous exchange resin column for impurity removal at a flow rate of 1 BV / h and a resin column volume of 1000 mL. After three cycles, components with a pH value lower than 1.8 are collected to obtain a vitamin C produced solution, which is concentrated and crystallized to obtain vitamin C.

[0119] The vitamin C mother solution used in Example 3 has a vitamin C content of 127.4 g / L and a gulonic acid content of 156.8 g / L;

[0120] The vitamin C prepared by the method of Example 3 has a purity of 95.78% and a yield of 86.5%.

[0121] Comparative Example 1

[0122] Based on Example 1, the changes are as follows:

[0123] In the step of preparing the macroporous exchange resin, the step of preparing the resin matrix additive is omitted, and in the mixing step, the resin matrix additive is replaced by an equal amount of untreated silica;

[0124] The rest of the operations are the same.

[0125] The vitamin C mother solution used in Comparative Example 1 has a vitamin C content of 127.4 g / L and a gulonic acid content of 156.8 g / L;

[0126] The vitamin C prepared by the method of Comparative Example 1 has a purity of 85.56% and a yield of 78.4%.

[0127] Comparative Example 2

[0128] Based on Example 1, the changes are as follows:

[0129] (1) In the step of preparing the resin matrix, equal amounts of sodium dodecylbenzene sulfonate and Tween 80 in the mixed solution 1 are replaced with deionized water;

[0130] (2) In the step of preparing the resin matrix additive, the preparation of the primary additive is omitted, and the primary additive is replaced by an equal amount of untreated silicon dioxide, wherein the particle size of the silicon dioxide is 280 nm;

[0131] The rest of the operations are the same.

[0132] The vitamin C mother solution used in Comparative Example 2 has a vitamin C content of 127.4 g / L and a gulonic acid content of 156.8 g / L;

[0133] The vitamin C prepared by the method of Comparative Example 2 has a purity of 87.62% and a yield of 80.3%.

[0134] Performance Testing

[0135] The macroporous exchange resins prepared in Examples 1-3 and Comparative Examples 1-2 were recycled and regenerated 30 times, and the macroporous exchange resins were recycled and regenerated after each ion exchange step. At the 30th recycling and regeneration, the yield and purity of the extracted vitamin C were as follows:

[0136] The recovery and regeneration method is as follows: the macroporous exchange resin after the ion exchange step is placed in 3 volumes of 6wt% sodium hydroxide solution, stirred at 25°C for 3.0 hours, filtered and washed, and then placed in 3 volumes of 10wt% hydrochloric acid solution again, stirred at 25°C for 3.0 hours, filtered and washed until the pH value of the filtered water reaches 6.8, and then dried at 110°C to obtain a regenerated macroporous exchange resin;

[0137]

[0138] The present invention first prepares a resin matrix, then performs sulfonation so that the surface of the resin matrix contains more sulfonic acid groups, and then uses silicon dioxide to prepare a resin matrix auxiliary agent. After the silicon dioxide is dispersed by sodium oleate and glyceryl monostearate, microwave irradiation is performed so that more lattice defects and distortions are generated on the surface of the silicon dioxide, thereby increasing the specific surface area of ​​the silicon dioxide and further increasing the contact area with the feed liquid. In addition, aminosilane treatment is performed on the silicon dioxide so that amino groups are grafted on the surface of the silicon dioxide, so that the silicon dioxide and the resin matrix can be better connected, the bonding force is good, and the stability is good. The surface of the silicon dioxide carries more negative charges, which can be balanced by cations. Therefore, the prepared resin matrix auxiliary agent has good adsorption performance, and the combination of the silicon dioxide with the resin matrix enhances the adsorption performance and ion exchange performance of the macroporous exchange resin, improves the stability performance, and still has good ion exchange performance after multiple recycling and regeneration, and has a good extraction effect on vitamin C. The prepared vitamin C product has high purity and yield.

[0139] Comparative Example 1 omits the preparation of the resin matrix, and directly mixes the untreated silica with the resin matrix. The dispersibility of the silica is poor, the agglomeration force is relatively serious, and the compatibility with the resin matrix is ​​poor. In addition, the silica is not treated with aminosilane, and the combination with the resin matrix is ​​poor, and the stability is poor, thereby reducing the ion exchange performance, the extraction effect of vitamin C is poor, and the product purity and yield are low;

[0140] In Comparative Example 2, in the step of preparing the resin matrix, the sodium dodecylbenzene sulfonate and Tween 80 components in Mixing 1 were omitted, resulting in uneven composition of the resin matrix. In the step of preparing the resin matrix auxiliary agent, the silicon dioxide was directly treated with aminosilane. The dispersibility of the silicon dioxide was poor, and the treatment with aminosilane was uneven, which resulted in unstable binding with the resin matrix, ultimately reducing the extraction effect of the vitamin C product, and reducing the product purity and yield.

[0141] Unless otherwise specified, all ratios and percentages described in the present invention are by mass ratios and percentages are by mass percentages.

[0142] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for extracting vitamin C from a vitamin C mother solution, characterized in that: The method comprises the steps of salt formation, separation, preparation of macroporous exchange resin, and ion exchange; The salt-forming step comprises heating the vitamin C mother solution to 51-55° C. at a rate of 1.8-2.2° C. / min, adding a sodium hydroxide solution, controlling the pH value to 6.0-6.4, and performing ultrasonic treatment. After the ultrasonic treatment, heating the mother solution to 58-62° C. at a rate of 0.4-0.6° C. / min, adding activated clay, stirring for 11-15 minutes, and filtering after the stirring to obtain a mixed salt solution. The separation step comprises concentrating the mixed salt solution at a concentration temperature of 65-69° C. to 0.47-0.50 times the volume of the mixed salt solution, then reducing the temperature to 14-16° C. at a rate of 0.8-1.2° C. / min, stirring at 14-16° C. for 6.0-6.4 hours at a stirring speed of 104-115 rpm, and after the stirring is completed, gulonic acid salt is precipitated, leaving the separated vitamin C mother liquor; The preparation of the macroporous exchange resin includes the steps of preparing a resin matrix, sulfonation, preparing a resin matrix auxiliary agent, and mixing; The step of preparing the resin matrix comprises: adding the mixed solution 2 to the mixed solution 1, stirring evenly, heating to 71-75°C at a rate of 2.7-3.2°C / min, stirring for reaction for 3.0-3.4h, and stirring at a speed of 164-175rpm, then heating to 94-98°C at a rate of 1.2-1.4°C / min, stirring for reaction for 3.8-4.2h, and stirring at a speed of 117-124rpm, and after the stirring reaction is completed, naturally cooling to room temperature, washing, and drying at 66-70°C for 4.7-5.0h to obtain the resin matrix; The first mixed solution is a mixture of deionized water, polyvinyl alcohol, sodium dodecylbenzene sulfonate and Tween 80; the second mixed solution is a mixture of styrene, dipropylene benzene, benzoyl peroxide and paraffin; The sulfonation step is to sulfonate the resin matrix with a sulfuric acid solution; The steps of preparing the resin matrix auxiliary agent are as follows: placing silicon dioxide in a sealed container, adding an ethanol solution and stirring evenly, then adding sodium oleate and glyceryl monostearate, stirring evenly and then irradiating with microwaves, while performing ball milling treatment during microwave irradiation, filtering and drying to obtain a primary auxiliary agent; placing the primary auxiliary agent in an ethanol solution and stirring, stirring evenly, adding 3-aminopropyltriethoxysilane, raising the temperature to 65-69° C., stirring for 3.8-4.3 hours, filtering, washing and drying after the stirring is completed to obtain a resin matrix auxiliary agent; The mixing step comprises placing the sulfonated resin in a sealed container, adding deionized water, raising the temperature to 84-88° C., adding a resin matrix additive, stirring after the addition is completed, the stirring speed is 135-145 rpm, the stirring time is 58-62 min, and after the stirring is completed, filtering and drying to obtain a macroporous exchange resin; The ion exchange step is to pump the separated vitamin C mother liquor into a macroporous exchange resin column for impurity removal, with a flow rate of 1 BV / h and a resin column volume of 1000 mL. After three cycles, components with a pH value lower than 1.6-1.8 are collected to obtain a vitamin C extracted solution, which is concentrated and crystallized to obtain vitamin C.

2. A method for extracting vitamin C from vitamin C mother solution according to claim 1, characterized in that: In the step of preparing the resin matrix, the mass ratio of the mixed solution 1 to the mixed solution 2 is 7.48-7.53:2.84-2.

88.

3. A method for extracting vitamin C from vitamin C mother solution according to claim 1, characterized in that: In the step of preparing the resin matrix, the preparation method of the mixed solution 1 is to add polyvinyl alcohol, sodium dodecylbenzene sulfonate and Tween 80 into deionized water, stir at a temperature of 52-55° C., stir evenly, and then naturally cool to room temperature to obtain the mixed solution 1; The mass ratio of the deionized water, polyvinyl alcohol, sodium dodecylbenzene sulfonate and Tween 80 is 146-153:0.41-0.45:0.12-0.16:0.25-0.27; The preparation method of the mixed solution II is to add styrene, dipropylene benzene and benzoyl peroxide into a reaction container for ultrasonic treatment, wherein the ultrasonic time is 32-36 minutes, the ultrasonic power is 73-78W, and the ultrasonic frequency is 30-34kHz. After the ultrasonic treatment, paraffin is added and stirred to obtain the mixed solution II. The mass ratio of styrene, dipropylene benzene, benzoyl peroxide and paraffin is 16.6-17.0:1.8-2.2:0.18-0.22:2.2-2.

4.

4. A method for extracting vitamin C from vitamin C mother solution according to claim 1, characterized in that: The sulfonation step comprises placing the resin matrix in a reaction container, introducing a sulfuric acid solution, stirring at 223-235 rpm and heating to 92-96° C., stirring at 92-96° C. for 2.4-2.6 hours, and after the stirring is completed, continuing to heat to 120-125° C., keeping the temperature and stirring for 4.4-4.6 hours, and after the stirring is completed, naturally cooling to room temperature, washing, filtering, and drying to obtain a sulfonated resin; The mass concentration of the sulfuric acid solution is 88-92%; The mass ratio of the resin matrix to the sulfuric acid solution is 6.3-6.7:24.5-25.

0.

5. A method for extracting vitamin C from vitamin C mother solution according to claim 1, characterized in that: In the step of preparing the resin matrix additive, the microwave irradiation has an irradiation time of 10-14 minutes, an irradiation power of 514-525W, and an irradiation temperature of 107-112°C; The ball milling process has a ball milling speed of 205-215 rpm and a ball-to-material ratio of 5-7:

1.

6. A method for extracting vitamin C from vitamin C mother solution according to claim 1, characterized in that: The particle size of the silicon dioxide is 275-285 nm; The mass concentration of the ethanol solution is 43-47%; The mass ratio of the silicon dioxide, ethanol solution, sodium oleate and glyceryl monostearate is 10.3-10.7:90-95:0.7-0.9:0.2-0.4; The mass ratio of the primary auxiliary agent, the ethanol solution and 3-aminopropyltriethoxysilane is 6.5-6.9:82-87:0.62-0.

66.

7. A method for extracting vitamin C from vitamin C mother solution according to claim 1, characterized in that: In the mixing step, the mass ratio of the sulfonated resin, deionized water, and resin matrix additive is 5.6-6.0 g:98-104 mL:1.3-1.5 g.

8. A method for extracting vitamin C from vitamin C mother solution according to claim 1, characterized in that: In the salt-forming step, the ultrasonic treatment has an ultrasonic time of 14-18 min, an ultrasonic power of 80-85 W, and an ultrasonic frequency of 27-32 kHz; The mass concentration of the sodium hydroxide solution is 48-52%; The particle size of the activated clay is 230-250nm; The mass volume ratio of the vitamin C mother solution and the white clay is 180-220 mL:1.0-1.4 g.

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