Purification method of 13C caprylic acid and 13C caprylic acid

Abstract

The invention provides a 13C octanoic acid purification method and 13C octanoic acid, and relates to the technical field of chemical drugs, the 13C octanoic acid purification method comprises the following steps: dissolving a 13C octanoic acid crude product, adjusting the pH value, crystallizing, and taking crystals to obtain a 13C octanoic acid finished product. The recrystallization method is used for treating the crude product, decolorizing and removing impurities, impurities introduced in the 13C octanoic acid synthesis process can be effectively removed, and the purity of the purified product is improved. According to the purification method, reagents are cheap and easy to obtain, the treatment process is simple and easy to implement, no special equipment requirement exists, industrial production can be achieved, and the purification method has important significance on production and application of 13C octanoic acid.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical drug purification, in particular to a 13 Purification method of C octanoic acid and 13 C octanoic acid. Background Art

[0002] Due to its non-invasive, non-radioactive, high sensitivity and good specificity, stable isotopes have become 13 Great progress has been made in the research of C-labeled diagnostic reagents. 13 The success of the C-urea breath test in detecting Helicobacter pylori has 13 The C breath test is increasingly used in clinical testing and diagnosis. As one of the most important digestive organs in the human body, the stomach plays an important role in the storage, digestion, and absorption of food. Gastric emptying, as an important indicator of the stomach, is related to nearly twenty diseases including gastric ulcers, gastric cancer, diabetes, hypothyroidism, Parkinson's disease, etc. Therefore, accurate detection of gastric emptying is of great significance for disease diagnosis. Gastric emptying detection generally includes intubation, absorption test, real-time ultrasound, radionuclide method, etc. And using 13 Compared with the above methods, the use of C octanoic acid as a diagnostic reagent to detect gastric emptying using a breath test has obvious advantages such as being non-invasive and non-radioactive.

[0003] 13 C octanoic acid has broad application prospects as a diagnostic reagent for breath test gastric emptying detection, but its crude product contains a variety of impurities. The presence of impurities seriously affects the purity and abundance of the product, making the gastric emptying test results less reliable and difficult to meet the requirements of the breath test. At the same time, impurities have certain toxicity and may cause harm to the human body during clinical use of drugs. Therefore, how to effectively remove them through purification means is a hot topic. 13 The impurities produced during the synthesis of C octanoic acid have become an urgent problem to be solved.

[0004] Patent CN101417939B discloses a 13 A method for preparing C octanoic acid, wherein the crude octanoic acid is obtained by using a Grignard reaction and then the crude product is purified by acid-base inversion. Experimental verification shows that the octanoic acid obtained by the method still contains many impurities and the product purity is low.

[0005] 13 C octanoic acid is an oily liquid at room temperature. The commonly used methods for purifying oily substances are distillation, column chromatography, etc., but the purification effects are not ideal.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] One of the purposes of the present invention is to provide a13 The invention provides a method for purifying C octanoic acid to at least solve one of the technical problems existing in the prior art. 13 The purification method of C octanoic acid can effectively remove 13 C Impurities in crude octanoic acid.

[0008] The second object of the present invention is to provide a method of 13 Purification method of C octanoic acid 13 C octanoic acid. 13 Purification method of C octanoic acid 13 C octanoic acid has higher yield and purity.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] In a first aspect, the present invention provides a 13 The purification method of C octanoic acid comprises the following steps:

[0011] right 13 The crude product of C octanoic acid was dissolved, pH value was adjusted and crystallized in sequence, and the crystals were obtained. 13 C octanoic acid finished product.

[0012] Furthermore, the solvent used for the dissolution includes at least one of n-hexane, acetonitrile, acetonitrile / water, acetone, ethyl acetate, cyclohexane, dichloromethane and ethanol.

[0013] Furthermore, the 13 The mass volume ratio of the crude C octanoic acid to the solvent is 1:(1-10).

[0014] Furthermore, the dissolution temperature is 10-40°C, and the dissolution time is 0.5-3h.

[0015] Furthermore, before adjusting the pH value, after dissolving 13 Add adsorbent to the crude solution of C-octanoic acid, stir to decolorize, and then filter once;

[0016] Preferably, the 13 The mass ratio of the crude C octanoic acid to the adsorbent is 1:(0.01-0.20);

[0017] Preferably, the adsorbent comprises activated carbon;

[0018] Preferably, the stirring bleaching temperature is 10 to 40° C., and the stirring bleaching time is 1 to 3 hours.

[0019] Furthermore, after dissolution 13 C. The pH value of the crude octanoic acid solution is adjusted to 2 to 4, preferably 2 to 3;

[0020] Preferably, an acid is used to adjust the pH;

[0021] Preferably, the acid agent comprises at least one of formic acid, acetic acid, hydrochloric acid and sulfuric acid.

[0022] Further, the crystallization includes crystallization by cooling;

[0023] Preferably, the temperature of the cooling and crystallization is -10 to -40°C, and the time of the cooling and crystallization is 3 to 6 hours.

[0024] Furthermore, the 13 The purification method of C octanoic acid also comprises the following steps:

[0025] After the crystallization, secondary filtration is performed to obtain a solid product, and then the solvent in the solid product is removed;

[0026] Preferably, the secondary filtration comprises reduced pressure filtration;

[0027] Preferably, the vacuum pressure of the reduced pressure filtration is -0.085 to -0.095 MPa;

[0028] Preferably, the instrument used for the secondary filtration is pre-cooled.

[0029] Furthermore, the removing the solvent from the solid product comprises: concentrating the solid product under reduced pressure;

[0030] Preferably, the temperature of the reduced pressure concentration is 30 to 60° C., and the vacuum pressure of the reduced pressure concentration is -0.09 to -0.10 MPa.

[0031] In a second aspect, the present invention provides a 13 Purification method of C octanoic acid 13 C octanoic acid.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides 13 The purification method of C octanoic acid is carried out by 13 C octanoic acid crude product was dissolved and the pH value of the solution was adjusted to make 13 C-caprylic acid tends to form a stable crystalline structure, which helps promote 13 The crystallization of C octanoic acid was realized by recrystallization. 13 Purification of crude C octanoic acid can effectively remove 13 C octanoic acid is introduced during the synthesis process to improve the purity of the purified product. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 The embodiment of the present invention provides 13 C Liquid chromatogram of crude octanoic acid;

[0036] Figure 2 The purified product obtained in Example 1 of the present invention 13 Liquid chromatogram of C octanoic acid product. DETAILED DESCRIPTION

[0037] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] A first aspect of the present invention provides a 13 The purification method of C octanoic acid comprises the following steps:

[0040] right 13 The crude product of C octanoic acid was dissolved, pH value was adjusted and crystallized in sequence, and the crystals were obtained. 13 C octanoic acid finished product.

[0041] 13 C octanoic acid is an oily liquid at room temperature, and it is not easy to purify it by common solid purification methods such as recrystallization and beating. 13 C octanoic acid crude product was dissolved and the pH value of the solution was adjusted to make 13 C-caprylic acid tends to form a stable crystalline structure, which helps promote 13 The crystallization of C octanoic acid was realized by recrystallization. 13 Purification of crude C octanoic acid can effectively remove 13C octanoic acid is introduced during the synthesis process to improve the purity of the purified product.

[0042] In some preferred embodiments, the solvent used for dissolving includes at least one of n-hexane, acetonitrile, acetonitrile / water, acetone, ethyl acetate, cyclohexane, dichloromethane and ethanol.

[0043] In some preferred embodiments, the 13 The mass volume ratio of the crude C octanoic acid to the solvent is 1:(1-10), for example, it can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc.

[0044] The solvent selected by the present invention is purified by recrystallization 13 C octanoic acid provides a viable basis for different solvents and 13 C octanoic acid can form solutions with different solubility. By changing the type or proportion of solvent, the 13 C-octanoic acid solubility in solution and crystallization behavior, thereby facilitating the separation of impurities.

[0045] In some preferred embodiments, the dissolution temperature is 10-40°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc., and the dissolution time is 0.5-3h, for example, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, etc.

[0046] In some preferred embodiments, before adjusting the pH value, 13 Add activated carbon to the crude solution of C-octanoic acid, stir to decolorize, and then filter once;

[0047] Preferably, the adsorbent comprises activated carbon;

[0048] In the present invention, activated carbon is added as an adsorbent to remove impurities in the solution. The use of activated carbon can not only help remove impurities insoluble in the target solvent, but also assist in improving the transparency of the solution, creating better conditions for subsequent recrystallization.

[0049] Preferably, the 13 The mass ratio of the crude C octanoic acid to the activated carbon is 1:(0.01-0.20), for example, 1:0.01, 1:0.15, 1:0.20, etc.;

[0050] Preferably, the stirring bleaching temperature is 10-40°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc., and the stirring bleaching time is 1-3h, for example, 1h, 1.5h, 2h, 2.5h, 3h, etc.

[0051] In some preferred embodiments, the dissolved 13 The pH value of the crude octanoic acid solution is adjusted to 2 to 4, for example, 2, 3, and 4, etc., preferably 2 to 3, for example, 2 and 3, etc.;

[0052] In the present invention, by accurately adjusting the pH value of the solution to a specific range, it helps to promote 13 C octanoic acid crystals are precipitated. Under appropriate pH conditions, 13 C-octanoic acid tends to form a stable crystalline structure rather than remain in a liquid state, thereby improving the purification yield.

[0053] Preferably, an acid is used to adjust the pH;

[0054] Preferably, the acid agent comprises at least one of formic acid, acetic acid, hydrochloric acid and sulfuric acid.

[0055] In some preferred embodiments, the crystallization includes temperature reduction crystallization;

[0056] Preferably, the temperature of the cooling crystallization is -10 to -40°C, for example, -10°C, -15°C, -20°C, -25°C, -30°C, -35°C, -40°C, etc., and the time of the cooling crystallization is 3 to 6h, for example, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, etc.

[0057] In the present invention, the crystallization operation is carried out under low temperature conditions to promote the target compound 13 C octanoic acid is crystallized with higher purity, which is beneficial to improve the purity of the target compound.

[0058] In some preferred embodiments, the 13 The purification method of C octanoic acid also comprises the following steps:

[0059] After the crystallization, secondary filtration is performed to obtain a solid product, and then the solvent in the solid product is removed;

[0060] Preferably, the secondary filtration comprises reduced pressure filtration;

[0061] Preferably, the vacuum pressure of the reduced pressure filtration is -0.085 to -0.095 MPa;

[0062] Preferably, the instrument used for the secondary filtration is pre-cooled.

[0063] In the present invention, the instrument used for secondary filtration is preferably a Buchner funnel, and a pre-cooled Buchner funnel is used for reduced pressure filtration.

[0064] In some preferred embodiments, removing the solvent from the solid product comprises: concentrating the solid product under reduced pressure;

[0065] In the present invention, the reduced pressure concentration is adopted to avoid chemical reaction and decomposition possibly caused by high temperature, and to ensure the recovery and reuse of the solvent, thereby improving the purity and yield of the final product.

[0066] Preferably, the temperature of the reduced pressure concentration is 30-60°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, etc., and the vacuum pressure of the reduced pressure concentration is -0.09-0.10MPa, for example, -0.09MPa, -0.095MPa, -0.10MPa, etc.

[0067] Furthermore, the 13 The purification method of C octanoic acid comprises the following steps:

[0068] (1) To 13 Add solvent to the crude octanoic acid and stir until completely dissolved;

[0069] (2) Adding activated carbon to the crude product solution, stirring to decolorize, and filtering;

[0070] (3) adjusting the pH value of the filtrate with acid, cooling and crystallizing, and filtering under reduced pressure using a pre-cooled Buchner funnel;

[0071] (4) The solid obtained by filtration in (3) was concentrated under reduced pressure, and the solvent was evaporated to obtain 13 C octanoic acid finished product.

[0072] A second aspect of the present invention provides a 13 Purification method of C octanoic acid 13 C octanoic acid.

[0073] In the present invention, by selecting a suitable solvent, controlling the amount of solvent added and the crystallization temperature, and adjusting the pH value of the system, the crude product is decolorized and purified by recrystallization, which can effectively remove 13 The impurities introduced during the synthesis of C octanoic acid are removed to improve the purity of the purified product. The purification method has cheap and readily available reagents, a simple purification method, a simple and easy treatment process, mild conditions, no special equipment requirements, and can be industrialized for production. 13 The production and application of C octanoic acid are of great significance.

[0074] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0075] In the embodiments of the present invention and the comparative examples 13C octanoic acid crude product is obtained by 13 The product is prepared by reacting carbon dioxide with n-heptylmagnesium bromide, adding hydrochloric acid or sulfuric acid to quench the reaction, extracting the product, adjusting the base with sodium hydroxide, and adjusting the acid with hydrochloric acid to obtain 13 C octanoic acid crude product. Prepared by the above method 13 The liquid chromatogram of crude C octanoic acid is as follows Figure 1 shown.

[0076] In the following embodiments, the vacuum pressure used in the reduced pressure filtration is -0.085 to -0.095 MPa.

[0077] Example 1

[0078] This embodiment provides a 13 The purification method of C octanoic acid comprises the following steps:

[0079] To 50g 13 Add 150 ml of n-hexane to the crude C octanoic acid, and stir at room temperature (25°C) for 1 hour until it is completely dissolved. Add 2.5 g of activated carbon, stir and decolorize at 20-30°C for 2 hours; filter, rinse the filter cake with 10 ml of n-hexane, and combine the filtrate. Use acetic acid to adjust the pH value of the system to 2.5, cool to -20-30°C, stir and crystallize for 4 hours, and filter under reduced pressure using a pre-cooled Buchner funnel. The solid is quickly transferred to a 500 ml single-mouth bottle, concentrated under reduced pressure at 40°C and a vacuum pressure of -0.09-0.10 MPa, and the solvent is evaporated to obtain 42.5 g of a colorless oil. 13 C octanoic acid finished product.

[0080] The purified product obtained by the above method 13 The liquid chromatogram of the finished product of C octanoic acid is as follows Figure 2 shown.

[0081] Example 2

[0082] This embodiment provides a 13 The purification method of C octanoic acid comprises the following steps:

[0083] To 50g 13 Add 100 ml of acetonitrile to the crude C octanoic acid, and stir at room temperature (25°C) for 2 hours until completely dissolved. Add 5.0 g of activated carbon, stir and decolorize at 20-30°C for 1 hour; filter, rinse the filter cake with 10 ml of acetonitrile, and combine the filtrate. Adjust the pH value of the filtrate to 3.0 with formic acid, cool to -10-20°C, stir and crystallize for 3 hours, and filter under reduced pressure using a pre-cooled Buchner funnel. Quickly transfer the solid to a 500 ml single-mouth bottle, concentrate at 50°C and a vacuum pressure of -0.09-0.10 MPa, and evaporate the solvent to obtain 43.0 g of colorless oil. 13 C octanoic acid finished product.

[0084] Example 3

[0085] This embodiment provides a 13 The purification method of C octanoic acid comprises the following steps:

[0086] To 50g 13 Add 100 ml of acetone to the crude C octanoic acid, and stir at room temperature (25°C) for 1 hour until completely dissolved. Add 2.5 g of activated carbon, stir and decolorize at 20-30°C for 2 hours; filter, rinse the filter cake with 10 ml of acetone, and combine the filtrate. Use 1N hydrochloric acid to adjust the pH value of the system to 3.5, cool to -20-30°C, stir and crystallize for 4 hours, and filter under reduced pressure using a pre-cooled Buchner funnel. Quickly transfer the solid to a 500 ml single-mouth bottle, concentrate at 40°C and a vacuum pressure of -0.09-0.10 MPa, and evaporate the solvent to obtain 42.3 g of colorless oil. 13 C octanoic acid finished product.

[0087] Example 4

[0088] This embodiment provides a 13 The purification method of C octanoic acid comprises the following steps:

[0089] To 50g 13 Add 250 ml of ethyl acetate to the crude C octanoic acid, and stir at room temperature (25°C) for 2 hours until completely dissolved. Add 3.5 g of activated carbon, stir and decolorize at 30-40°C for 1 hour; filter, rinse the filter cake with 20 ml of ethyl acetate, and combine the filtrate. Use 0.1N sulfuric acid to adjust the pH value of the system to 4.0, cool to -15--25°C, stir and crystallize for 3 hours, and filter under reduced pressure using a pre-cooled Buchner funnel. Quickly transfer the solid to a 500 ml single-mouth bottle, concentrate at 50°C and a vacuum pressure of -0.09--0.10 MPa, and evaporate the solvent to obtain 43.6 g of colorless oil. 13 C octanoic acid finished product.

[0090] Example 5

[0091] This embodiment provides a 13 The purification method of C octanoic acid comprises the following steps:

[0092] To 100g 13Add 200 ml of acetonitrile / water mixed solvent (acetonitrile to water volume ratio of 1:1) to the crude C octanoic acid, and stir at room temperature (25°C) for 2 hours until completely dissolved. Add 5.0 g of activated carbon, stir and decolorize at 20-30°C for 1 hour; filter, rinse the filter cake with 20 ml of acetonitrile / water mixed solvent, and combine the filtrate. Use acetic acid to adjust the pH value of the system to 2.5, cool to -20-30°C, stir and crystallize for 5 hours, and filter under reduced pressure using a pre-cooled Buchner funnel. The solid is quickly transferred to a 500 ml single-mouth bottle, concentrated under reduced pressure at 55°C and a vacuum pressure of -0.09-0.10 MPa, and the solvent is evaporated to obtain 88.2 g of colorless oil. 13 C octanoic acid finished product.

[0093] Example 6

[0094] This embodiment provides a 13 The purification method of C octanoic acid comprises the following steps:

[0095] To 100g 13 Add 150 ml of n-hexane / ethanol mixed solvent (volume ratio of n-hexane to ethanol is 1:1) to the crude C octanoic acid, and stir at room temperature (25°C) for 1 hour until completely dissolved. Add 6.0 g of activated carbon, stir and decolorize at 25-35°C for 1 hour; filter, rinse the filter cake with 15 ml of n-hexane, and combine the filtrate. Use 1N hydrochloric acid to adjust the pH value of the system to 3.5, cool to -25--35°C, stir and crystallize for 6 hours, and filter under reduced pressure using a pre-cooled Buchner funnel. The solid is quickly transferred to a 500 ml single-mouth bottle, concentrated under reduced pressure at 50°C and a vacuum pressure of -0.09--0.10 MPa, and the solvent is evaporated to obtain 83.4 g of colorless oil. 13 C octanoic acid finished product.

[0096] Example 7

[0097] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that the pH value of the system is adjusted to 2, and the rest is the same as that of Example 5.

[0098] Example 8

[0099] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that the pH value of the system is adjusted to 3, and the rest is the same as that of Example 5.

[0100] Example 9

[0101] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that the pH value of the system is adjusted to 3.5, and the rest is the same as that of Example 5.

[0102] Example 10

[0103] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that:

[0104] 100 ml of acetonitrile / water mixed solvent was stirred at 10 °C for 3 h until completely dissolved;

[0105] Add 1.0g activated carbon, stir and decolorize at 10-20℃ for 3h; filter, rinse the filter cake with 10ml acetonitrile / water mixed solvent, and combine the filtrate;

[0106] After adjusting the pH, cool down to -30~-40℃;

[0107] The mixture was concentrated under reduced pressure at 30°C to obtain 88.5 g of a colorless oil. 13 C octanoic acid finished product;

[0108] The remaining steps are consistent with Example 5.

[0109] Embodiment 11

[0110] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 10 in that:

[0111] The acetonitrile / water mixed solvent is 1000 ml, and stirred at 40°C for 0.5 h until completely dissolved;

[0112] Add 20 g of activated carbon; use 100 ml of acetonitrile / water mixed solvent to elute the filter cake, and combine the filtrate;

[0113] The mixture was concentrated under reduced pressure at 60°C to obtain 83.2 g of a colorless oil. 13 C octanoic acid finished product;

[0114] The remaining steps are consistent with Example 10.

[0115] Example 12

[0116] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that the pH value of the system is adjusted to 1.5, and the rest is the same as that of Example 5.

[0117] Embodiment 13

[0118] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that the pH value of the system is adjusted to 4.5, and the rest is the same as that of Example 5.

[0119] Embodiment 14

[0120] This embodiment provides a 13The purification method of C octanoic acid is different from that of Example 5 in that the acetonitrile / water mixed solvent is 50 ml, and the rest is the same as that of Example 5.

[0121] Embodiment 15

[0122] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that the acetonitrile / water mixed solvent is 1050 ml, and the rest is the same as that of Example 5.

[0123] Example 16

[0124] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that after adjusting the pH value of the solution, the temperature is lowered to -5°C, and the rest is the same as that of Example 5.

[0125] Embodiment 17

[0126] This embodiment provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that after adjusting the pH value of the solution, the temperature is lowered to -45°C, and the rest is the same as that of Example 5.

[0127] Comparative Example 1

[0128] This comparative example provides a 13 The purification method of C octanoic acid is different from that of Example 5 in that:

[0129] No pH adjustment operation was performed, and the remaining steps were consistent with Example 5.

[0130] Comparative Example 2

[0131] This comparative example provides a 13 The purification method of C octanoic acid is purified by distillation. The specific steps are as follows: take 100g 13 C octanoic acid crude product was put into a 250ml distillation flask, stirred and heated, and distilled under reduced pressure, and the vacuum pressure was controlled to be ≤-0.095MPa. The distillate with a temperature below 120℃ was collected as the front fraction, and the distillate with a temperature between 120℃ and 140℃ was collected as the product. A total of 70.5g of light yellow oil was obtained. 13 C octanoic acid finished product.

[0132] Comparative Example 3 This comparative example provides a 13 The purification method of C octanoic acid is carried out by column chromatography. The specific steps are as follows: take 50.0g 13The crude product of C octanoic acid was added to a chromatography column filled with 200-300 mesh silica gel, and ethyl acetate / petroleum ether was used as the eluent, and the gradient elution was carried out at 1:10, 1:8, 1:6, 1:4, and 1:2 (volume ratio). The eluate with high purity was collected and concentrated under reduced pressure at 45-50°C to obtain 30.2 g of colorless oil. 13 C octanoic acid finished product.

[0133] Test Case

[0134] Test sample: purified by the purification method of Example 1-17 13 C octanoic acid and purified by the purification method of Comparative Examples 1-3 13 C octanoic acid.

[0135] The yield of the test sample was calculated and the purity was tested, and the obtained data are shown in Table 1 below.

[0136] Table 1

[0137] Yield (%) purity(%) Example 1 85.0 100.00 Example 2 86.0 99.95 Example 3 84.6 99.92 Example 4 87.2 99.93 Example 5 88.2 100.00 Example 6 83.4 100.00 Example 7 87.6 100.00 Example 8 87.5 100.00 Example 9 86.1 99.96 Example 10 88.5 99.91 Embodiment 11 83.2 100.00 Example 12 82.5 99.86 Embodiment 13 81.6 99.90 Embodiment 14 88.4 96.32 Embodiment 15 81.2 99.99 Example 16 80.6 99.95 Embodiment 17 88.3 98.20 Comparative Example 1 78.6 98.10 Comparative Example 2 70.5 95.68 Comparative Example 3 60.4 94.50

[0138] It can be seen from the data in the table that compared with the data results of Example 5, Example 7, Example 8 and Example 9, the 13 When the pH value of the crude octanoic acid solution is adjusted to 2-3, the yield of the product is significantly improved; and the yield and purity of the product prepared within the specific parameter range of the embodiment of the present invention are significantly improved.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A 13 The method for purifying C octanoic acid is characterized in that: The following steps are involved: right 13 The crude product of C octanoic acid was dissolved, pH value was adjusted and crystallized in sequence, and the crystals were obtained. 13 C octanoic acid finished product.

2. according to claim 1 13 The method for purifying C octanoic acid is characterized in that: The solvent used for the dissolution includes at least one of n-hexane, acetonitrile, acetonitrile / water, acetone, ethyl acetate, cyclohexane, dichloromethane and ethanol.

3. According to claim 2 13 The method for purifying C octanoic acid is characterized in that: Said 13 The mass volume ratio of the crude C octanoic acid to the solvent is 1:(1-10).

4. according to claim 1 13 The method for purifying C octanoic acid is characterized in that: The dissolving temperature is 10-40° C., and the dissolving time is 0.5-3 h.

5. According to claim 1 13 The method for purifying C octanoic acid is characterized in that: Before adjusting the pH value, after dissolution 13 Add adsorbent to the crude solution of C-octanoic acid, stir to decolorize, and then filter once; Preferably, the 13 The mass ratio of the crude C octanoic acid to the adsorbent is 1:(0.01-0.20); Preferably, the adsorbent comprises activated carbon; Preferably, the stirring bleaching temperature is 10 to 40° C., and the stirring bleaching time is 1 to 3 hours.

6. According to claim 1 13 The method for purifying C octanoic acid is characterized in that: After dissolution 13 C. The pH value of the crude octanoic acid solution is adjusted to 2 to 4, preferably 2 to 3; Preferably, an acid is used to adjust the pH; Preferably, the acid agent comprises at least one of formic acid, acetic acid, hydrochloric acid and sulfuric acid.

7. According to claim 1 13 The method for purifying C octanoic acid is characterized in that: The crystallization includes temperature reduction crystallization; Preferably, the temperature of the cooling and crystallization is -10 to -40°C, and the time of the cooling and crystallization is 3 to 6 hours.

8. According to claim 1 13 The method for purifying C octanoic acid is characterized in that: Said 13 The purification method of C octanoic acid also comprises the following steps: After the crystallization, secondary filtration is performed to obtain a solid product, and then the solvent in the solid product is removed; Preferably, the secondary filtration comprises reduced pressure filtration; Preferably, the vacuum pressure of the reduced pressure filtration is -0.085 to -0.095 MPa; Preferably, the instrument used for the secondary filtration is pre-cooled.

9. The method according to claim 8 13 The method for purifying C octanoic acid is characterized in that: The removing the solvent from the solid product comprises: concentrating the solid product under reduced pressure; Preferably, the temperature of the reduced pressure concentration is 30 to 60° C., and the vacuum pressure of the reduced pressure concentration is -0.09 to -0.10 MPa.

10. The method according to any one of claims 1 to 9. 13 Purification method of C octanoic acid 13 C octanoic acid.

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