A method for crystallizing malic acid ion exchange liquid

Abstract

The application provides a crystallization method of malic acid ion exchange liquid. The crystallization method comprises the following steps: (1) concentrating the malic acid ion exchange liquid to saturation to obtain saturated liquid; and (2) performing cooling crystallization treatment on the saturated liquid, and flowing ethyl acetate into the saturated liquid. The malic acid prepared by the application has good quality, high purity, uniform crystal particle size and high yield.

Description

Technical Field

[0001] This invention relates to a method for crystallizing malic acid ion exchange solution. Background Technology

[0002] Malic acid is a very important organic acid and one of the intermediate products of the tricarboxylic acid cycle (TCA). It is a white crystalline powder or crystalline substance with strong hygroscopic properties, readily soluble in water and ethanol, and has a characteristic pleasant sour taste. It is widely used in the food manufacturing industry, such as as a food additive, preservative, and flavoring agent, and also in the pharmaceutical and daily chemical industries, where there is a significant market demand for malic acid.

[0003] Currently, the main production methods for malic acid include chemical synthesis, fermentation, and enzymatic methods. Conventional production processes suffer from problems such as low crystallization rate, small crystal size, high moisture content in wet crystals, high drying costs, poor flowability of dried products, easy moisture absorption, and easy clumping, which are not conducive to storage and transportation. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a method for crystallizing malic acid ion exchange solution.

[0005] A method for crystallizing malic acid ion exchange solution includes the following steps:

[0006] (1) Concentrate the malic acid ion exchange solution to saturation to obtain a saturated solution;

[0007] (2) Cool the saturated liquid to allow it to crystallize, and simultaneously add ethyl acetate to the saturated liquid.

[0008] The malic acid ion exchange solution described in this application refers to malic acid liquid that has undergone deionization and decationization treatment.

[0009] According to some embodiments of the crystallization method of the present invention, in step (1), the concentration of the malic acid ionizing solution is 30-40% (mm); for example, 30%, 35%, or 40%.

[0010] According to some embodiments of the crystallization method of the present invention, the concentration temperature is 50-55°C; for example, 50°C, 53°C, 55°C.

[0011] According to some embodiments of the crystallization method of the present invention, the mass concentration of malic acid in the saturated solution is 75-80%; for example, 75%, 78%, 80%.

[0012] According to some embodiments of the crystallization method of the present invention, the concentration pressure is 0.06-0.10 MPa; for example, 0.06 MPa, 0.08 MPa, or 0.10 MPa.

[0013] According to some embodiments of the crystallization method of the present invention, in step (2), the cooling rate is 1-3℃ / h; for example, 1℃ / h, 1.5℃ / h, 2℃ / h, 3℃ / h.

[0014] According to some embodiments of the crystallization method of the present invention, the endpoint temperature of the cooling is 15-25°C; for example, 15°C, 18°C, 20°C, 22°C, 25°C.

[0015] According to some embodiments of the crystallization method of the present invention, in step (2), when the saturated liquid is cooled to 40-46°C, seed crystals are added, and ethyl acetate is simultaneously added to the saturated liquid.

[0016] According to some embodiments of the crystallization method of the present invention, the flow rate of the ethyl acetate is 35-120 g / h; for example, 35 g / h, 60 g / h, 80 g / h, 100 g / h, 120 g / h.

[0017] According to some embodiments of the crystallization method of the present invention, the seed crystals include finished malic acid.

[0018] According to some embodiments of the crystallization method of the present invention, the seed crystal has a mesh size of 40-80 mesh.

[0019] According to some embodiments of the crystallization method of the present invention, the amount of seed crystal added is 1% to 3% of the mass of the crystal slurry.

[0020] According to some embodiments of the crystallization method of the present invention, step (3) is further included, in which the product obtained in step (2) is subjected to solid-liquid separation, ethyl acetate is recovered from the mother liquor, wet malic acid crystals are obtained, and the wet malic acid crystals are dried to obtain malic acid.

[0021] According to some embodiments of the crystallization method of the present invention, the drying temperature is 55-65°C; for example, 55°C, 58°C, 60°C, 62°C, 65°C.

[0022] According to some embodiments of the crystallization method of the present invention, the drying time is 2-4 hours; for example, 2 hours, 3 hours, or 4 hours.

[0023] The beneficial effects of this invention include:

[0024] 1. The malic acid prepared by this invention has high purity, good crystal morphology, uniform particle size, and high yield.

[0025] 2. The malic acid prepared by this invention has low moisture content, high stability, and is not prone to clumping, making it easy to store and transport.

[0026] 3. The preparation method of this invention has low energy consumption and short production time. Attached Figure Description

[0027] Figure 1 Crystal diagram of the malic acid product obtained in Example 1;

[0028] Figure 2 This is a crystal diagram of the malic acid product obtained in Example 2;

[0029] Figure 3 Crystal diagram of the malic acid product obtained in Example 3;

[0030] Figure 4 The image shows the crystal structure of the malic acid product obtained in Comparative Example 1.

[0031] Figure 5 The image shows the crystal structure of the malic acid product obtained in Comparative Example 2.

[0032] Figure 6 The image shows the crystal structure of the malic acid product obtained in Comparative Example 3.

[0033] Figure 7 The image shows the crystal structure of the malic acid product obtained in Comparative Example 4.

[0034] Figure 8 The image shows the crystal structure of the malic acid product obtained in Comparative Example 5.

[0035] Figure 9 The image shows the crystal structure of the malic acid product obtained in Comparative Example 6.

[0036] Figure 10 The image shows the crystal structure of the malic acid product obtained in Comparative Example 7.

[0037] Figure 11 Crystal diagram of the malic acid product obtained in Comparative Example 8;

[0038] Figure 12 The image shows the crystal structure of the malic acid product obtained in Comparative Example 9. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0040] In this paper, the total yield of malic acid is calculated as follows: (mass of wet malic acid crystals / mass of malic acid ionizing solution * acidity of ionizing solution) * 100%.

[0041] In the following examples and comparative examples, the pressure for vacuum concentration was 0.08 MPa.

[0042] The method for preparing the seed crystals in this invention is as follows: the malic acid product is crushed and sieved to a mesh size of 40-80.

[0043] Example 1

[0044] (1) 10 kg of malic acid decolorizing ionization solution with a mass concentration of 35% was concentrated at 50°C. 5.34 kg of water was discharged, yielding 4.66 kg (75% m / m) of saturated malic acid solution;

[0045] (2) The obtained malic acid solution was injected into a crystallizer with an initial temperature of 50°C. The temperature was decreased by 1°C per hour for 5 consecutive hours until the temperature of the saturated malic acid solution reached 45°C. A small number of fine crystal nuclei appeared. 3% of the saturated solution was added with 40-mesh self-made seed crystals and stirred slowly. Ethyl acetate was added simultaneously at a flow rate of 38 g / h, with a total solvent addition of 1026 g.

[0046] (3) Based on step (2), control the cooling rate at 1°C per hour, and the cooling endpoint is 18°C. A large number of crystals appear to obtain crystal slurry.

[0047] (4) The crystal slurry was centrifuged to separate the malic acid wet crystals, yielding 2.65 kg of malic acid wet crystals, with a total yield of 74.88%.

[0048] (5) The obtained wet crystals were dried at 55℃ for 4 hours to obtain the finished malic acid product. The finished product had a content of 99.6% and a moisture content of 0.11%, as shown in Table 1. The crystal diagram of the finished malic acid product is shown in the figure below. Figure 1 As shown.

[0049] Example 2

[0050] (1) 10 kg of 35% malic acid decolorizing ionization solution was concentrated under reduced pressure at 53°C, and 5.5 kg of water was discharged to obtain 4.5 kg (78% m / m) saturated solution.

[0051] (2) The obtained saturated malic acid solution was injected into the crystallizer at an initial temperature of 53°C. The temperature was reduced by 1.5°C per hour for 8.5 hours until the temperature reached 40.25°C. A small number of fine crystal nuclei appeared. 4% seed crystals were added and stirred slowly. Ethyl acetate was slowly added at a flow rate of 90 g / h and a total solvent addition of 1155 g.

[0052] (3) Based on step (2), control the cooling rate at 1.5°C per hour, and the cooling endpoint is 21°C, at which point a large number of crystals appear;

[0053] (4) The obtained crystal slurry was centrifuged and separated, yielding 2.74 kg of wet malic acid crystals, with a total yield of 78.3%;

[0054] (5) The obtained wet crystals were dried at 57℃ for 3 hours to obtain the malic acid product. The product content was 99.5% and the moisture content was 0.12%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 2 As shown.

[0055] Example 3

[0056] (1) 10 kg of malic acid decolorizing ionization solution with a mass concentration of 35% was concentrated at a temperature of 55℃, and 5.63 kg of water was discharged to obtain 4.37 kg (80% m / m) saturated solution.

[0057] (2) The obtained saturated malic acid solution was injected into a crystallizer with an initial temperature of 55°C. The temperature was decreased by 2°C per hour for 6 hours until the temperature reached 42°C. A small number of fine crystal nuclei appeared. 5% (by weight of the saturated solution) of 40-mesh seed crystals were added and the mixture was stirred slowly. Ethyl acetate was added at a flow rate of 130 g / h, with a total added amount of 1105 g.

[0058] (3) Based on step (2), control the cooling rate at 2°C per hour, and the cooling endpoint is 25°C, at which point a large number of crystals appear;

[0059] (4) The obtained crystal slurry was centrifuged and separated, yielding 2.8 kg of wet malic acid crystals, with a total yield of 80%.

[0060] (5) The obtained wet crystals were dried at 60°C for 2 hours to obtain the malic acid product. Testing showed that the malic acid content was 99.4% and the moisture content was 0.1%, as shown in Table 1. The crystal structure of the malic acid product is shown in the figure below. Figure 3 As shown.

[0061] Comparative Example 1

[0062] The only difference between Comparative Example 1 and Example 3 is the flow rate and amount of ethyl acetate added.

[0063] Specifically: (1) 10 kg of malic acid decolorizing ionization solution with an acidity of 35% was concentrated under reduced pressure at a temperature of 55°C, and 5.63 kg of water was discharged to obtain 4.38 kg (80% m / m) of saturated malic acid solution;

[0064] (2) The saturated malic acid solution obtained in the previous step was injected into a crystallizer with an initial temperature of 54°C. The temperature was decreased by 2°C per hour for 6 hours until the crystallization solution temperature reached 42°C. A small number of fine crystal nuclei appeared. Seed crystals of 5% by mass of the saturated solution were added and the mixture was stirred slowly. Ethyl acetate was added at a flow rate of 34.54 g / h, with a total added amount of 656 g.

[0065] (3) Control the cooling rate at 2°C per hour, with a final cooling temperature of 25°C, at which point a large number of crystals appear;

[0066] (4) The obtained crystal slurry was centrifuged and separated, yielding 2.46 kg of wet malic acid crystals with a moisture content of 1.1% and a total yield of 70.2%.

[0067] (5) The obtained wet crystals were dried at 60℃ for 2 hours to obtain the malic acid product, with a malic acid content of 90.5% and a moisture content of 2.1%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 4 As shown.

[0068] Comparative Example 2

[0069] The only difference between Comparative Example 2 and Example 3 is the cooling rate and time.

[0070] (1) 10 kg of malic acid decolorizing ionization solution with an acidity of 35% was concentrated under reduced pressure at a temperature of 55℃, and 5.51 kg of water was discharged to obtain 4.49 kg (78% m / m) saturated solution.

[0071] (2) The malic acid saturated solution obtained in the step is injected into the crystallizer with an initial temperature of 53°C. The temperature is reduced by 1.5°C per hour. After 7.33 hours, the temperature of the crystallization solution is 42°C. A small number of fine crystal nuclei appear. 5% seed crystals are added and stirred slowly.

[0072] (3) Slowly add ethyl acetate at a flow rate of 130 g / h, with a total solvent addition of 1105 g.

[0073] (4) Control the cooling rate at 1°C per hour, with the final temperature of 22°C, at which point a large number of crystals appear.

[0074] (5) The obtained crystal slurry was centrifuged and separated, yielding 2.52 kg of wet malic acid crystals with a moisture content of 1.2% and a total yield of 71.95%.

[0075] (6) The obtained wet crystals were dried at 60℃ for 3 hours to obtain the malic acid product. The product content was 90.3% and the moisture content was 3.12%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 5 As shown.

[0076] Comparative Example 3

[0077] The only difference between Comparative Example 3 and Example 3 is the cooling rate.

[0078] (1) 10 kg of malic acid decolorizing ionization solution with an acidity of 35% was concentrated under reduced pressure at a temperature of 55℃, and 5.63 kg of water was discharged to obtain 4.37 kg (77% m / m) saturated solution.

[0079] (2) The obtained saturated malic acid solution was injected into a crystallizer with an initial temperature of 54°C. The temperature was decreased by 2°C per hour for 6 consecutive hours until the crystallization solution temperature reached 42°C. A small number of fine crystal nuclei appeared. 5% seed crystals were added and the mixture was stirred slowly. Ethyl acetate was slowly added at a flow rate of 130 g / h, with a total solvent addition of 1105 g / h.

[0080] (3) Control the cooling rate at 1.2°C per hour, with a final cooling temperature of 25°C, at which point a large number of crystals appear;

[0081] (4) The obtained crystal slurry was centrifuged and separated, yielding 2.35 kg of wet malic acid crystals with a moisture content of 1.3% and a total yield of 70.04%.

[0082] (5) The obtained wet crystals were dried at 60℃ for 2 hours to obtain the malic acid product. The product content was 91.2% and the moisture content was 2.1%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 6 As shown.

[0083] Comparative Example 4

[0084] The only difference between Comparative Example 4 and Example 3 is that the flow rate of ethyl acetate is different.

[0085] (1) 10 kg of malic acid decolorizing ion exchange solution with an acidity of 35% was concentrated under reduced pressure at a temperature of 55℃, and 5.63 kg of water was discharged to obtain a 4.37 (76% m / m) saturated solution.

[0086] (2) The obtained saturated malic acid solution was injected into a crystallizer with an initial temperature of 54°C. The temperature was decreased by 2°C per hour for 6 hours until it reached 42°C. A small number of fine crystal nuclei appeared. 5% seed crystals were added and the mixture was stirred slowly. Ethyl acetate was slowly added at a flow rate of 84.47 g / h, with a total solvent addition of 1105 g.

[0087] (3) Control the cooling rate at 2°C per hour, with a final cooling temperature of 25°C, at which point a large number of crystals appear;

[0088] (4) The obtained crystal slurry was centrifuged and separated, yielding 2.41 kg of wet malic acid crystals with a moisture content of 1.1% and a total yield of 72.5%.

[0089] (5) The obtained wet crystals were dried at 60℃ for 2 hours to obtain the malic acid product. The product content was 90.4% and the moisture content was 2.11%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 7 As shown.

[0090] Comparative Example 5

[0091] The only difference between Comparative Example 5 and Example 3 is the amount of ethyl acetate added.

[0092] (1) 10 kg of malic acid decolorizing ion exchange solution with an acidity of 35% was concentrated at 55°C to obtain 5.06 kg of water and 4.94 kg (79% m / m) of saturated solution.

[0093] (2) The obtained saturated malic acid solution was injected into a crystallizer with an initial temperature of 54°C. The temperature was reduced by 2°C per hour for 6 hours until it reached 42°C. A small number of fine crystal nuclei appeared. 5% seed crystals were added and the mixture was stirred slowly. Ethyl acetate was added slowly at a flow rate of 130 g / h, with a total solvent addition of 889 g.

[0094] (3) Control the cooling rate at 2°C per hour, with a final cooling temperature of 25°C, at which point a large number of crystals appear;

[0095] (4) The crystal slurry was separated by centrifugation, yielding 2.73 kg of wet malic acid crystals with a moisture content of 1.3% and a total yield of 70%.

[0096] (6) The wet crystals were dried at 56℃ for 3 hours to obtain the malic acid product. The product content was 90.6% and the moisture content was 2.1%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 8 As shown.

[0097] Comparative Example 6

[0098] The only difference between Comparative Example 6 and Example 3 is that ethyl acetate is not added. Specifically, it includes:

[0099] (1) 10 kg of malic acid decolorizing ion exchange solution with an acidity of 35% was concentrated at 55°C to remove 5.6 kg of water, yielding 4.3 kg (80% m / m) of saturated solution.

[0100] (2) The initial temperature of the malic acid saturated solution injected into the crystallizer is 54°C. The temperature is reduced by 2°C per hour. After 6 hours, the temperature reaches 42°C and a small number of fine crystal nuclei appear. 5% of seed crystals are added and the mixture is stirred slowly.

[0101] (3) The cooling rate is 2°C per hour, and the cooling endpoint is 25°C, at which point a large number of crystals appear.

[0102] (4) The obtained crystal slurry was centrifuged to obtain 2.42 kg of wet malic acid crystals, with a total yield of 70.22%;

[0103] (5) The wet crystals were dried at 60℃ for 2 hours to obtain the malic acid product. The malic acid content was tested to be 91.2% and the moisture content was 2.2%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 9 As shown.

[0104] Comparative Example 7

[0105] The only difference between Comparative Example 7 and Example 3 is that ethyl acetate is replaced with ethanol. Specifically, it includes:

[0106] (1) 10 kg of malic acid decolorizing ion exchange solution with an acidity of 35% was concentrated at 55°C to remove 5.63 kg of water, yielding 4.37 kg (80% m / m) of saturated solution.

[0107] (2) The obtained saturated malic acid solution was injected into a crystallizer with an initial temperature of 54°C. The temperature was decreased by 2°C per hour until the temperature reached 42°C after 6 hours. A small number of fine crystal nuclei appeared. 5% seed crystals were added and the mixture was stirred slowly. Ethanol was added simultaneously at a flow rate of 130 g / h, with a total addition of 1105 g.

[0108] (3) Control the cooling rate, cooling down by 2°C per hour, with the final temperature of 25°C, at which point a large number of crystals appear;

[0109] (4) The crystal slurry was centrifuged to obtain 2.44 kg of wet malic acid crystals, with a total yield of 69.88%.

[0110] (5) The wet crystals were dried at 60°C for 2 hours to obtain the malic acid product. The malic acid content was tested to be 90.05% and the moisture content was 2.8%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 10 As shown.

[0111] Comparative Example 8

[0112] The only difference between Comparative Example 8 and Example 3 is that ethyl acetate is replaced with acetonitrile. Specifically, it includes...

[0113] (1) 10 kg of malic acid decolorizing ion exchange solution with an acidity of 35% was concentrated at 55°C to remove 5.63 kg of water, yielding 4.3 kg (78% m / m) of saturated solution.

[0114] (2) Saturated malic acid solution was injected into the crystallizer at an initial temperature of 54°C. The temperature was decreased by 2°C per hour for 6 hours until the temperature reached 42°C. A small number of fine crystal nuclei appeared. 5% seed crystals were added and the mixture was stirred slowly. Acetonitrile was added simultaneously at a flow rate of 130 g / h, with a total addition of 1105 g.

[0115] (3) Control the cooling rate, cooling down by 2°C per hour, with a final temperature of 25°C, at which point a large number of crystals appear;

[0116] (4) The crystal slurry was centrifuged to obtain 2.31 kg of wet malic acid crystals, with a total yield of 68.9%;

[0117] (5) The wet crystals were dried at 60℃ for 2 hours to obtain the malic acid product. The malic acid content was tested to be 90.2% and the moisture content was 2.0%, as shown in Table 1. The crystal diagram of the malic acid product is shown in the figure. Figure 11 As shown.

[0118] Comparative Example 9

[0119] The only difference between Comparative Example 9 and Example 3 is the temperature at which the seed crystals were added. Specifically, this includes:

[0120] (1) 10 kg of malic acid decolorizing ion exchange solution with an acidity of 35% was concentrated at 55°C to remove 5.63 kg of water, yielding 4.37 kg (79% m / m) of saturated solution.

[0121] (2) The obtained saturated malic acid solution was injected into a crystallizer with an initial temperature of 54°C. The temperature was decreased by 2°C per hour for 10 hours until the temperature reached 34°C. A small number of fine crystal nuclei appeared. 5% of 4-crystal seed crystals were added and the mixture was stirred slowly. Ethyl acetate was added simultaneously at a flow rate of 130 g / h, with a total addition of 1105 g.

[0122] (3) Control the cooling rate, cooling down by 2°C per hour, with the final temperature of 25°C, at which point a large number of crystals appear;

[0123] (4) The crystal slurry was centrifuged to obtain 2.33 kg of wet malic acid crystals, with a total yield of 67.5%;

[0124] (5) The wet crystals were dried at 60°C for 2 hours to obtain the malic acid product. The malic acid content was measured to be 89.9% and the moisture content 2.3%, as shown in Table 1. The crystal structure of the malic acid product is shown in the figure below. Figure 12 As shown.

[0125] Table 1

[0126]

[0127] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for crystallizing malic acid ion exchange solution, comprising the following steps: (1) The malic acid ion exchange solution is concentrated to saturation to obtain a saturated solution; wherein the mass concentration of malic acid in the saturated solution is 75-80%; (2) Cooling the saturated liquid to induce crystallization, while simultaneously adding ethyl acetate to the saturated liquid; wherein the cooling rate is 1-2℃ / h; the final temperature of the cooling is 15-25℃; the amount of ethyl acetate added is 10%~30% of the saturated liquid; and the flow rate of ethyl acetate is 35g~120g / h. (3) The product obtained in step (2) is subjected to solid-liquid separation to obtain wet malic acid crystals, and the wet malic acid crystals are dried to obtain malic acid; wherein the drying temperature is 55-65℃ and the drying time is 2-4h; In step (2), when the saturated liquid cools down to 40-46°C, seed malic acid is added, and ethyl acetate is added to the saturated liquid.

2. The crystallization method according to claim 1, characterized in that, In step (1), the mass concentration of the malic acid ion exchange solution is 30-40%.

3. The crystallization method according to claim 1, characterized in that, The concentration temperature is 50-55℃.

4. The crystallization method according to claim 1, characterized in that, The concentration pressure is 0.06-0.10 MPa.

5. The crystallization method according to claim 1, characterized in that, The seed crystals have a mesh size of 40 to 80.

6. The crystallization method according to claim 1, characterized in that, The amount of seed crystals added is 1% to 3% of the saturated liquid.

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