High-purity abscisic acid and purification method of abscisic acid crude product

Abstract

The invention discloses high-purity abscisic acid and an abscisic acid crude product purification method, and belongs to the technical field of abscisic acid purification. The invention solves the problem of how to provide an abscisic acid purification method which is simple in process and can effectively improve the purity of abscisic acid. The method comprises the following steps: S1, mixing an abscisic acid crude product with an acetonitrile aqueous solution to obtain a mixed solution; s2, heating the mixed solution to 80 to 90 DEG C; s3, carrying out gradient cooling on the mixed solution to 10-20 DEG C; s4, fully stirring to separate out abscisic acid crystals in the mixed solution; and S5, filtering and drying to obtain the high-purity abscisic acid. The purity of the obtained abscisic acid is 99% or above, the product yield is higher than 86%, and the method is easy and convenient to operate and easy for industrialized large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of abscisic acid purification, and particularly relates to a high-purity abscisic acid and a purification method of abscisic acid crude product. BACKGROUND

[0002] Abscisic acid (ABA) is a plant hormone with a sesquiterpene structure, and is named because it can promote leaf abscission. It is one of the five natural plant growth regulators. The main effects of abscisic acid on plant growth include (1) inducing stress resistance gene expression, stimulating stress resistance immune system, resisting external environment such as drought, cold wave, disease and insect pests, and salt and alkali; (2) controlling flower bud differentiation and adjusting flowering period; (3) promoting the accumulation of protein and sugar in seeds and fruits, and improving the quality of crops and fruits, etc. In the field of medical health, abscisic acid can stimulate insulin secretion and reduce insulin and blood glucose levels, so abscisic acid has a broad application prospect in the fields of agriculture and medicine.

[0003] In existing research, the research reports on the purification and crystal form of abscisic acid mainly include the following:

[0004] Patent CN105439846A discloses that the purity of abscisic acid can be increased to more than 93% by using a mixed solvent of ethanol or acetone and water.

[0005] Patent CN106905142A discloses that the purity of abscisic acid can be increased to more than 95% by using a mixed solvent of methanol or ethanol and water.

[0006] Patent CN103274927A discloses a method for increasing the purity of abscisic acid to more than 99%, but the operation is complicated, and the eighth step of crystallization operation needs to use ethanol for recrystallization five times.

[0007] Patent CN111285762A discloses that the purity of abscisic acid can be increased to more than 98% by using a mixed solvent of methanol or ethanol and water for crystallization, but column chromatography separation operation is needed before crystallization, which is not suitable for industrial production.

[0008] Patent CN116730831A discloses that the addition of a crystallization aid can make the abscisic acid crystals completely precipitate, but the purity of the obtained abscisic acid is only 90%, and the patent does not identify the abscisic acid crystals.

[0009] The purification method of high-purity abscisic acid has been a research hotspot, and the existing purification methods are generally complicated in operation, large in organic solvent usage, and low in efficiency. SUMMARY

[0010] The present application provides a high-purity abscisic acid and a purification method of abscisic acid crude product in order to solve the problem of how to provide a simple process and effectively improve the purity of abscisic acid in the prior art.

[0011] The technical scheme adopted by the present application is as follows:

[0012] A purification method of abscisic acid crude product, comprising the following steps:

[0013] S1: mixing abscisic acid crude product with acetonitrile aqueous solution to obtain a mixed solution;

[0014] S2: heating the mixed solution to 80-90 DEG C;

[0015] S3: gradient cooling the mixed solution to 10-20 DEG C;

[0016] S4: fully stirring to precipitate abscisic acid crystals in the mixed solution;

[0017] S5: obtaining high-purity abscisic acid after filtration and drying.

[0018] As preferred, the specific process of gradient cooling in S3 comprises:

[0019] S301: reducing the temperature of the mixed solution to 60-70 DEG C within 0.5 hours, and then stirring for crystallization for 1±0.5 hours;

[0020] S302: reducing the temperature of the mixed solution to 50-60 DEG C within 0.5 hours, and then stirring for crystallization for 1±0.5 hours;

[0021] S303: repeating the temperature reduction and stirring for crystallization process of S302, and the temperature reduction range is 10±5 DEG C each time until the temperature is reduced to 10-20 DEG C.

[0022] As preferred, the volume concentration of the acetonitrile aqueous solution is 16.7%, and 20g of abscisic acid crude product is added into 180-240ml of acetonitrile aqueous solution to obtain the mixed solution in S1.

[0023] As preferred, the pore size of the filter paper used in the filtration process is 15-20μm, the drying temperature is 50-55 DEG C, and the time length is 20-24 hours.

[0024] As preferred, the purity of the abscisic acid crude product is at least 65%.

[0025] As preferred, the precipitation time in S4 is 10-12 hours.

[0026] A high-purity abscisic acid is purified by the purification method of abscisic acid.

[0027] Furthermore, the abscisic acid was identified by X-ray powder diffraction, and its main characteristic peaks were found at 2θ values ​​of 14.696°, 18.897°, 20.062°, 23.820°, 28.314°, 29.105°, 29.696°, 30.052°, 35.257°, ​​36.161°, 36.471°, 38.457°, 42.782°, and 47.311°.

[0028] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0029] The present invention selects acetonitrile aqueous solution as solvent primarily because: acetonitrile aqueous solution has a good effect on removing impurities; secondly, acetonitrile has good heat resistance, which can meet heating conditions of 80-90℃. Therefore, using acetonitrile aqueous solution as solvent not only achieves good impurity removal, but also can be combined with subsequent processes to achieve a technical effect of 1+1>2. Furthermore, the present invention controls crystallization by controlling the cooling process, allowing the product to crystallize slowly without encapsulating impurities, making purity easier to control, thus obtaining abscisic acid with higher purity. The final abscisic acid purity is above 99%, and the product yield is above 86%. This method is simple to operate and easy to scale up for industrial production. Attached Figure Description

[0030] Figure 1 This is a graph showing the HPLC purity results of the abscisic acid sample obtained in Example 1 of this invention.

[0031] Figure 2 The image shows the XRD pattern of the abscisic acid sample obtained in Example 1 of this invention.

[0032] Figure 3 This is a graph showing the HPLC purity results of the abscisic acid sample obtained in Example 2 of this invention.

[0033] Figure 4 The image shows the XRD pattern of the abscisic acid sample obtained in Example 2 of this invention.

[0034] Figure 5 This is a graph showing the HPLC purity results of the abscisic acid sample obtained in Example 3 of this invention.

[0035] Figure 6 The XRD pattern of the abscisic acid sample obtained in Example 3 of this invention;

[0036] Figure 7 This is a graph showing the HPLC purity results of the abscisic acid sample obtained in Example 4 of this invention.

[0037] Figure 8 The XRD pattern of the abscisic acid sample obtained in Example 4 of this invention;

[0038] Figure 9 HPLC purity result chart of the abscisic acid sample obtained in the present application Comparative Example 1;

[0039] Figure 10 XRD chart of the abscisic acid sample obtained in the present application Comparative Example 1;

[0040] Figure 11 HPLC purity result chart of the abscisic acid sample obtained in the present application Comparative Example 2. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0042] Embodiment 1

[0043] A method for purifying an abscisic acid crude product, comprising the following steps:

[0044] S1: mixing 20 g of an abscisic acid crude product with a purity of 65% with 240 ml of an acetonitrile aqueous solution (analytical grade) (the volume ratio of acetonitrile to water is 1:5) to obtain a mixed solution;

[0045] S2: heating the mixed solution to 80℃;

[0046] S3: gradiently cooling the mixed solution to 20℃, and the specific process is as follows:

[0047] S301: reducing the temperature of the mixed solution to 70℃ within 0.5 hours, and then stirring for crystallization for 1 hour (not including the cooling time, and specifically referring to the crystallization time of 1 hour), at this time, a small amount of crystals begins to precipitate;

[0048] S302: reducing the temperature of the mixed solution to 60℃ within 0.5 hours, and then stirring for crystallization for 1 hour (not including the cooling time, and specifically referring to the crystallization time of 1 hour);

[0049] S303: repeating the cooling and stirring for crystallization process of S302, and the temperature is reduced by 10℃ each time, until the temperature is reduced to 20℃, and the specific process is as follows:

[0050] reducing the temperature of the mixed solution to 50℃ within 0.5 hours, and then stirring for crystallization for 1 hour;

[0051] reducing the temperature of the mixed solution to 40℃ within 0.5 hours, and then stirring for crystallization for 1 hour;

[0052] The temperature of the mixture is decreased to 30°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour;

[0053] The temperature of the mixture is decreased to 20°C within 0.5 hour;

[0054] S4: The temperature of the mixture is maintained at 20°C, and then the mixture is stirred for 10-12 hours to fully precipitate the etoposide crystals in the mixture;

[0055] S5: After filtration and drying, high-purity etoposide is obtained.

[0056] The yield = the weight of the dried etoposide crystals / (the weight of the etoposide crude product * the purity). After calculation, the yield of this example is 86%, and the purity is 99.1% (). Figure 1 The crystal form of the stable etoposide obtained by crystallization and purification is identified by X-ray powder diffraction, and the results are shown in Figure 2 The main characteristic peaks of the spectrum are at 2θ values of 5.433°, 8.156°, 10.904°, 14.025°, 14.887°, 16.442°, 16.868°, 18.320°, 20.099°, 20.966°, 22.085°, 23.233°, 24.205°, 24.974°, 25.619°, 26.098°, 26.561°, 27.317°, 28.884°, 30.588°, 34.051°, 34.443°, 36.564°.

[0057] Example 2

[0058] The difference between this example and Example 1 is that the purity of the etoposide crude product is different, and the specific steps include the following steps:

[0059] S1: 20 g of etoposide crude product with a purity of 69% is mixed with 240 ml of acetonitrile aqueous solution (the volume ratio of acetonitrile to water is 1:5) to obtain a mixture;

[0060] S2: The mixture is heated to 80°C;

[0061] S3: The mixture is gradually cooled to 20°C, and the specific process is as follows:

[0062] S301: The temperature of the mixture is decreased to 70°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time of 1 hour), at which time a small amount of crystals begins to precipitate;

[0063] S302: The temperature of the mixture is decreased to 60°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time of 1 hour);

[0064] S303: repeat the temperature reduction and stirring crystallization process of S302, each time the temperature reduction is 10℃, until the temperature is reduced to 20℃, the specific process is as follows:

[0065] The temperature of the mixed solution is reduced to 50℃ within 0.5 hours, and then the mixed solution is stirred for crystallization for 1 hour;

[0066] The temperature of the mixed solution is reduced to 40℃ within 0.5 hours, and then the mixed solution is stirred for crystallization for 1 hour;

[0067] The temperature of the mixed solution is reduced to 30℃ within 0.5 hours, and then the mixed solution is stirred for crystallization for 1 hour;

[0068] The temperature of the mixed solution is reduced to 20℃ within 0.5 hours;

[0069] S4: keep the temperature of the mixed solution at 20℃, and then fully stir the mixed solution for 10-12 hours to make the etoposide crystals in the mixed solution fully precipitate;

[0070] S5: after filtration and drying, high-purity etoposide is obtained.

[0071] After calculation, the yield of this embodiment is 87%, and the purity is 99.8% Figure 3 ). The crystal form of the stable etoposide obtained by crystallization and purification is identified by X-ray powder diffraction, and the results are shown in Figure 4 The main characteristic peaks of the spectrum are at 2θ values of 5.465°, 8.195°, 10.934°, 14.002°, 14.868°, 16.451°, 16.893°, 18.309°, 20.096°, 20.973°, 22.070°, 23.228°, 24.221°, 24.913°, 25.603°, 26.039°, 26.553°, 27.337°, 28.905°, 30.600°, 33.992°, 34.471°, 36.596°.

[0072] Example 3

[0073] The difference between this embodiment and Example 1 is that the purity of the etoposide crude product is different, which comprises the following steps:

[0074] S1: 20g of etoposide crude product with a purity of 75% is mixed with 240ml of acetonitrile aqueous solution (the volume ratio of acetonitrile to water is 1:5) to obtain a mixed solution;

[0075] S2: heat the mixed solution to 80℃;

[0076] S3: reduce the temperature of the mixed solution to 20℃ in stages, and the specific process is as follows:

[0077] S301: The temperature of the mixed solution is reduced to 70°C within 0.5 hours, and then the crystallization is stirred for 1 hour (not including the temperature reduction time, specifically the crystallization time is 1 hour), at this time a small amount of crystals begins to precipitate;

[0078] S302: The temperature of the mixed solution is reduced to 60°C within 0.5 hours, and then the crystallization is stirred for 1 hour (not including the temperature reduction time, specifically the crystallization time is 1 hour);

[0079] S303: The temperature reduction and stirring crystallization process of S302 is repeated, each time the temperature is reduced by 10°C, until the temperature is reduced to 20°C, the specific process is as follows:

[0080] The temperature of the mixed solution is reduced to 50°C within 0.5 hours, and then the crystallization is stirred for 1 hour;

[0081] The temperature of the mixed solution is reduced to 40°C within 0.5 hours, and then the crystallization is stirred for 1 hour;

[0082] The temperature of the mixed solution is reduced to 30°C within 0.5 hours, and then the crystallization is stirred for 1 hour;

[0083] The temperature of the mixed solution is reduced to 20°C within 0.5 hours;

[0084] S4: The temperature of the mixed solution is maintained at 20°C, and then the crystallization of the shed acid crystals in the mixed solution is fully stirred for 10-12 hours;

[0085] S5: After filtration and drying, high-purity shed acid is obtained.

[0086] After calculation, the yield of this embodiment is 91%, and the purity is 99.9% Figure 5 The crystal form of the stable shed acid obtained by crystallization and purification is identified by X-ray powder diffraction, and the main characteristic peaks of its spectrum are at 2θ values of 5.431°, 8.156°, 10.930°, 14.024°, 14.884°, 16.454°, 16.904°, 18.319°, 20.096°, 20.968°, 22.088°, 23.227°, 24.196°, 24.945°, 25.603°, 26.043°, 26.550°, 27.325°, 28.888°, 30.583°, 34.001°, 34.457°, 36.558°( Figure 6 )。

[0087] Example 4

[0088] The difference between this embodiment and Example 1 is that the amount of acetonitrile aqueous solution is different, which comprises the following steps:

[0089] S1: 20 g of abscisic acid crude product with a purity of 65% was mixed with 180 ml of acetonitrile aqueous solution (volume ratio of acetonitrile to water was 1:5) to obtain a mixed solution;

[0090] S2: the mixed solution was heated to 80°C;

[0091] S3: the mixed solution was gradiently cooled to 20°C, and the specific process was as follows:

[0092] S301: the temperature of the mixed solution was reduced to 60°C within 0.5 hours, and then the crystallization was stirred for 1 hour (the cooling time was not included, and the crystallization time was 1 hour), at this time, a small amount of crystals began to precipitate;

[0093] S302: the temperature of the mixed solution was reduced to 50°C within 0.5 hours, and then the crystallization was stirred for 1 hour (the cooling time was not included, and the crystallization time was 1 hour);

[0094] S303: the cooling and stirring crystallization process of S302 was repeated, and the temperature was reduced to 10°C by 10°C each time, and the specific process was as follows:

[0095] the temperature of the mixed solution was reduced to 40°C within 0.5 hours, and then the crystallization was stirred for 1 hour;

[0096] the temperature of the mixed solution was reduced to 30°C within 0.5 hours, and then the crystallization was stirred for 1 hour;

[0097] the temperature of the mixed solution was reduced to 20°C within 0.5 hours, and then the crystallization was stirred for 1 hour;

[0098] the temperature of the mixed solution was reduced to 10°C within 0.5 hours;

[0099] S4: the temperature of the mixed solution was kept at 10°C, and then the abscisic acid crystals in the mixed solution were fully precipitated by stirring for 10-12 hours;

[0100] S5: high-purity abscisic acid was obtained after filtration and drying.

[0101] After calculation, the yield of this embodiment was 89%, and the purity was 98.8% Figure 7 The crystal form of the stable abscisic acid obtained by crystallization and purification was identified by X-ray powder diffraction, and the results were as follows Figure 8As shown, the main characteristic peaks of the atlas are at 2θ values of 5.446°, 8.165°, 10.910°, 13.992°, 14.853°, 16.422°, 16.863°, 18.292°, 20.096°, 20.942°, 22.050°, 23.202°, 24.173°, 24.938°, 25.579°, 26.024°, 26.527°, 27.302°, 28.860°, 30.567°, 33.984°, 34.427°, 36.533°.

[0102] Comparative Example 1

[0103] The comparative example is basically the same as Example 1, except that the crude abscisic acid product with a purity of 65% is added to 20 mL of ethyl acetate and dissolved by heating. 30 mL of petroleum ether is added dropwise to the solution, and stirring is performed after the addition is completed. Filtration and drying are performed to obtain an abscisic acid product with a yield of 88% and a purity of 84.3% (). Figure 9 The abscisic acid crystal obtained by crystallization purification is identified by X-ray powder diffraction, and the main characteristic peaks of the atlas are at 2θ values of 14.696°, 18.897°, 20.062°, 23.820°, 28.314°, 29.105°, 29.696°, 30.052°, 35.257°, 36.161°, 36.471°, 38.457°, 42.782°, 47.311°. Figure 10

[0104] Comparative Example 2

[0105] The comparative example is basically the same as Example 1, except that the solution is cooled to 20°C naturally after being dissolved by heating to 80°C, and the solution is stirred at 20°C for 10-12 hours. Filtration and drying are performed to obtain an abscisic acid product with a yield of 84% and a purity of 91.5% (). Figure 11

[0106] Comparative Example 3

[0107] The comparative example is basically the same as Example 1, except that the purity of the crude abscisic acid product is 50%, and an abscisic acid product with a yield of 83% and a purity of 96.7% is obtained by drying.

[0108] Comparative Example 4

[0109] The comparative example is basically the same as Example 1, except that the solution is dissolved by heating to 60°C, and an abscisic acid product with a yield of 87% and a purity of 98.4% is obtained.

[0110] Comparative Example 5

[0111] ​​The comparative example liquid is basically the same as example 1, except that S3: the mixed liquid is gradually cooled to 20°C, the specific process is as follows:

[0112] S301: the temperature of the mixed liquid is reduced to 70°C within 0.5 hours, and then stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time is 1 hour), at this time a small amount of crystals begins to precipitate;

[0113] S302: the temperature of the mixed liquid is reduced to 65°C within 0.5 hours, and then stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time is 1 hour);

[0114] S303: repeat the cooling and stirring crystallization process of S302, each time the temperature is reduced by 5°C, until the temperature is reduced to 20°C, the specific process is as follows:

[0115] the temperature of the mixed liquid is reduced to 60°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0116] the temperature of the mixed liquid is reduced to 55°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0117] the temperature of the mixed liquid is reduced to 50°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0118] the temperature of the mixed liquid is reduced to 45°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0119] the temperature of the mixed liquid is reduced to 40°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0120] the temperature of the mixed liquid is reduced to 35°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0121] the temperature of the mixed liquid is reduced to 30°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0122] the temperature of the mixed liquid is reduced to 25°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0123] the temperature of the mixed liquid is reduced to 20°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0124] S4: the temperature of the mixed liquid is maintained at 20°C, and then fully stirred for 10-12 hours to allow the crystal of etoposide in the mixed liquid to precipitate;

[0125] The yield of the etoposide product obtained is 85%, and the purity is 99.5%.

[0126] Comparative example 6

[0127] The mixture solution of this comparative example is basically the same as that of Example 1, except that S3: the mixture solution is gradually cooled to 20°C, and the specific process is as follows:

[0128] S301: the temperature of the mixture solution is reduced to 70°C within 0.5 hours, and then stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time of 1 hour), at which time a small amount of crystals begins to precipitate;

[0129] S302: the temperature of the mixture solution is reduced to 55°C within 0.5 hours, and then stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time of 1 hour);

[0130] S303: repeat the cooling and stirring crystallization process of S302, each time the temperature is reduced by 15°C, until the temperature is reduced to 20°C, and the specific process is as follows:

[0131] the temperature of the mixture solution is reduced to 40°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0132] the temperature of the mixture solution is reduced to 25°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0133] the temperature of the mixture solution is reduced to 10°C within 0.5 hours;

[0134] S4: the temperature of the mixture solution is maintained at 10°C, and then stirred thoroughly for 10-12 hours to allow the crystals of etodolac in the mixture solution to fully precipitate;

[0135] The yield of the obtained etodolac product is 85%, and the purity is 98.0%.

[0136] Comparative Example 7

[0137] The mixture solution of this comparative example is basically the same as that of Example 1, except that S3: the mixture solution is gradually cooled to 20°C, and the specific process is as follows:

[0138] S301: the temperature of the mixture solution is reduced to 70°C within 0.5 hours, and then stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time of 1 hour), at which time a small amount of crystals begins to precipitate;

[0139] S302: the temperature of the mixture solution is reduced to 60°C within 0.5 hours, and then stirred for crystallization for 1 hour (not including the cooling time, specifically the crystallization time of 1 hour);

[0140] S303: gradually cool, until the temperature is reduced to 20°C, and the specific process is as follows:

[0141] the temperature of the mixture solution is reduced to 45°C within 0.5 hours, and then stirred for crystallization for 1 hour;

[0142] The temperature of the mixture is reduced to 30°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour;

[0143] The temperature of the mixture is reduced to 15°C within 0.5 hour;

[0144] S4: The temperature of the mixture is kept at 15°C, and then the mixture is stirred for 10-12 hours to make the etoposide crystals in the mixture fully crystallize out;

[0145] The obtained etoposide product has a yield of 84% and a purity of 98.5%.

[0146] Comparative Example 8

[0147] The present comparative example is basically the same as Example 1, except that an ethanol aqueous solution is used instead of an acetonitrile aqueous solution, and the specific steps are as follows:

[0148] S1: 20 g of etoposide crude product with a purity of 65% is mixed with 240 ml of an ethanol aqueous solution (the volume ratio of ethanol to water is 1:5) to obtain a mixture;

[0149] S2: The mixture is heated to 80°C;

[0150] S3: The mixture is gradiently cooled to 20°C, and the specific process is as follows:

[0151] S301: The temperature of the mixture is reduced to 70°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour (the cooling time is not included, and the crystallization time is specifically 1 hour), at which time a small amount of crystals begins to crystallize out;

[0152] S302: The temperature of the mixture is reduced to 60°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour (the cooling time is not included, and the crystallization time is specifically 1 hour);

[0153] S303: The cooling and stirring crystallization process of S302 is repeated, and the temperature is reduced by 10°C each time until the temperature is reduced to 20°C, and the specific process is as follows:

[0154] The temperature of the mixture is reduced to 50°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour;

[0155] The temperature of the mixture is reduced to 40°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour;

[0156] The temperature of the mixture is reduced to 30°C within 0.5 hour, and then the mixture is stirred for crystallization for 1 hour;

[0157] The temperature of the mixture is reduced to 20°C within 0.5 hour;

[0158] S4: keeping the temperature of the mixed solution at 20℃, then fully stirring for 10-12 hours to make the crystal of the falling acid in the mixed solution dissolve out;

[0159] Through calculation, the yield of the present comparative example is 85%, and the purity is 98.8%.

[0160] Specifically, the specific parameter changes and results of Examples 1-4 and Comparative Examples 1-8 are shown in Table 1:

[0161] Table 1

[0162]

[0163]

[0164] As can be seen from Table 1, using acetonitrile water mixed solvent crystallization and gradient cooling crystallization method, the purity of the falling acid crude product with purity above 65% can be improved to above 98.8%, and the product yield is higher than 86%. If acetonitrile water mixed solvent crystallization or gradient cooling method is not used, the above purification effect cannot be achieved, which shows the necessity of using acetonitrile water mixed solvent crystallization and gradient cooling crystallization in the purification method.

[0165] The above examples only express the specific implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the protection scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the technical scheme concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application.

Claims

1. A method for purifying an abscisic acid crude product, characterized by: The method comprises the following steps: S1: mixing the crude abscisic acid with acetonitrile aqueous solution to obtain a mixture; S2: heating the mixture to 80-90℃; S3: gradiently cooling the mixture to 10-20℃; S4: fully stirring to precipitate the abscisic acid crystals in the mixture; S5: obtaining high-purity abscisic acid after filtration and drying.

2. The method for purifying abscisic acid crude product according to claim 1, characterized in that: The specific process of the gradiently cooling in S3 comprises: S301: reducing the temperature of the mixture to 60-70℃ within 0.5 hour, and then stirring to precipitate crystals for 1±0.5 hour; S302: reducing the temperature of the mixture to 50-60℃ within 0.5 hour, and then stirring to precipitate crystals for 1±0.5 hour; S303: repeating the temperature reduction and stirring to precipitate crystals in S302, and the temperature reduction range is 10±5℃ each time until the temperature is reduced to 10-20℃.

3. The method for purifying abscisic acid crude product according to claim 1, characterized in that: The volume concentration of the acetonitrile aqueous solution is 16.7%, and 20g of the crude abscisic acid is added into 180-240ml of the acetonitrile aqueous solution to obtain the mixture in S1.

4. The method for purifying abscisic acid crude product according to claim 1, characterized in that: The pore size of the filter paper used in the filtration is 15-20μm, the drying temperature is 50-55℃, and the drying time is 20-24 hours.

5. The method for purifying abscisic acid crude product according to claim 1, characterized in that: The purity of the crude abscisic acid is at least 65%.

6. The method for purifying abscisic acid crude product according to claim 5, characterized in that: The precipitation time in S4 is 10-12 hours.

7. A high purity abscisic acid, characterized by: The purified abscisic acid is obtained by the purification method of any one of claims 1-6.

8. The high purity abscisic acid according to claim 7, characterized by: The abscisic acid is identified by X-ray powder diffraction, and the main characteristic peaks of the pattern are at 2θ values of 14.696°, 18.897°, 20.062°, 23.820°, 28.314°, 29.105°, 29.696°, 30.052°, 35.257°, 36.161°, 36.471°, 38.457°, 42.782°, 47.311°.

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