A method for preparing cosmetic grade azelaic acid
By mixing the monomer saturated fatty acids from C2 to C9 and butyl acetate, adding oleic acid, pulse ultrasonic treatment, and ozone reaction and oxidation reaction, then performing program crystallization with n-heptane, and finally mixing with solvent for heating and stirring and cooling, the problem of low yield and low purity in the prior art is solved, and the preparation of high-purity cosmetic-grade azelaic acid is achieved, reducing the application risk.
Patent Information
- Application Number
- CN202411988291.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-08
AI Technical Summary
In the prior art, azelaic acid has a low yield, low purity, and a lot of impurities, resulting in certain risks in the use of cosmetics.
A cosmetic grade azelaic acid is adopted to prepare cosmetic grade azelaic acid by mixing monomer saturated fatty acids from C2 to C9 and butyl acetate, adding oleic acid, then undergoing pulse ultrasonic treatment, followed by ozonation and oxidation reactions, to obtain an oxide liquid, then mixing with n-heptane for program crystallization, and finally mixing with solvent for heating and stirring and cooling to obtain high-purity cosmetic grade azelaic acid.
This method directly obtains high-purity cosmetic grade azelaic acid with a purity of ≥99.8%, reducing impurities, reducing application risks, and improving the yield of azelaic acid.
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Figure CN119775123A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of chemical synthesis, and more specifically, relates to a method for preparing cosmetic-grade azelaic acid. Background Art
[0002] Azelaic acid is a straight-chain saturated dicarboxylic acid containing 9 carbon atoms, also known as azelaic acid, with two crystalline forms, α and β. It is widely used in many important fields such as engineering plastics, advanced flavors and fragrances, cosmetics, preservatives, adhesives, cross-linking agents, plasticizers, medical treatment, electronics, etc. The market demand is huge, and the requirements for specifications and purity are widely distributed. At present, the methods for obtaining azelaic acid on the market are mostly to obtain crude azelaic acid by distilling the oxidation liquid obtained after ozonation-oxidation of oleic acid, and then purifying it by crystallization extraction. This will result in a low yield of azelaic acid, and the purity is not high, there are many impurities, and there are certain risks in its application in cosmetics. Therefore, it is of great significance to develop a method for preparing high-purity cosmetic-grade azelaic acid. Summary of the invention
[0003] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.
[0004] In order to achieve these objects and other advantages of the present invention, a method for preparing cosmetic grade azelaic acid is provided, comprising the following steps:
[0005] Step 1, uniformly mixing C2-C9 monobasic saturated fatty acids and butyl acetate to obtain a mixed solvent, adding oleic acid to the mixed solvent, and subjecting the mixed solvent to pulse ultrasonic treatment to obtain a mixed solution;
[0006] Step 2, adding the mixed solution obtained in step 1 to an ozonation reactor to carry out an ozonation reaction, transferring the obtained oleic acid ozonate to an oxidation reactor to carry out an oxidation reaction to obtain an oxidized solution;
[0007] Step 3, mixing the oxidation solution with n-heptane, performing program crystallization, filtering, and drying to obtain crude azelaic acid;
[0008] Step 4: Mix the crude azelaic acid with a solvent, heat up and stir to dissolve, then cool down and stir to crystallize, filter, and dry to obtain cosmetic grade azelaic acid in different crystal forms.
[0009] Preferably, in the step 1, among the monobasic saturated fatty acids of C2 to C9, the content of nonanoic acid is 45 to 55%, the content of caproic acid is 25 to 35%, and the rest are other monobasic saturated fatty acids of C2 to C9; the mass ratio of the monobasic saturated fatty acids of C2 to C9 to butyl acetate is 8 to 12:1 to 3:0.2 to 0.8; and the mass ratio of oleic acid to the mixed solvent is 1:2 to 5.
[0010] Preferably, in step 1, the specific parameters of the pulse ultrasonic treatment are: power 100-500W, frequency 20-40kHz, duty cycle 50-80%, ultrasonic working time 3-12s, intermittent time 3-8s, and treatment time 20-40min.
[0011] Preferably, in the step 2, the ozonation reaction is specifically as follows: stirring is maintained at a speed of 80 to 150 r / min, an ozonated gas having an ozone content of 80 to 120 mg / L is introduced, and the reaction temperature is 20 to 40° C., until the ozone content in the introduced ozonated gas is consistent with the ozone content in the ozonated tail gas leaving the reaction system, and the reaction is terminated; the ozonated gas flow rate is 0.8 to 3 m 3 / h.
[0012] Preferably, in step 2, the oxidation reaction is specifically as follows: oxygen is introduced, the reaction temperature is 80-120°C, sampling and analyzing the composition of the oxidation liquid every 0.5-1h during the reaction, and the reaction is terminated when the azelaic acid content no longer increases to obtain the oxidation liquid; the oxygen flow rate is 0.5-2m 3 / h.
[0013] Preferably, in step three, the volume ratio of the oxidizing liquid to n-heptane is 4-6:1-3.
[0014] Preferably, in the step three, the programmed crystallization is specifically as follows: stirring speed 50-100 r / min, heating to 60°C at a rate of 1-3°C / min, keeping constant temperature for 0.2-1h, then cooling to 50°C at a rate of 0.2-1°C / min, keeping constant temperature for 0.5-1.5h, then cooling to 25°C at a rate of 0.5-1.5°C / min, keeping constant temperature for 0.2-1h.
[0015] Preferably, in step 4, the solvent is one of ethyl acetate and pure water.
[0016] Preferably, the mass ratio of crude azelaic acid to ethyl acetate is 1:3-4; the mass ratio of crude azelaic acid to pure water is 1:3.5.
[0017] Preferably, in step 4, when the solvent is ethyl acetate, the temperature is raised to 75°C and stirred to dissolve, then cooled to 45°C and stirred to crystallize, and the obtained cosmetic-grade azelaic acid is a β-crystalline form; when the solvent is pure water, the temperature is raised to 90°C and stirred to dissolve, then cooled to 73°C and stirred to crystallize, and the obtained cosmetic-grade azelaic acid is an α-crystalline form.
[0018] The present invention at least includes the following beneficial effects: the present invention abandons the traditional distillation of oxidation liquid through extraction crystallization, directly solvent crystallizes the oxidation liquid obtained after ozonation-oxidation of oleic acid, avoids the energy consumption of high temperature and the loss in the distillation stage, directly obtains crude azelaic acid, and then uses solvent extraction crystallization to obtain high-purity cosmetic-grade azelaic acid products of different crystal forms, with a purity of ≥99.8%, reducing impurities and reducing application risks; in addition, the mixed solvent system used in the present invention, combined with the cavitation effect and mechanical vibration effect of pulsed ultrasound, can improve the solubility of oleic acid and the uniform dispersion of each component in the mixed liquid, which is beneficial to mass transfer and heat transfer in subsequent reactions, promotes the reaction, and improves the stability and selectivity of the reaction, thereby increasing the yield of azelaic acid.
[0019] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The XRD pattern of the cosmetic grade azelaic acid prepared in Example 1 of the present invention;
[0021] Figure 2 This is the XRD pattern of the cosmetic grade azelaic acid prepared in Example 3 of the present invention;
[0022] Figure 3 This is the GC spectrum of the cosmetic-grade azelaic acid prepared in Example 3 of the present invention. DETAILED DESCRIPTION
[0023] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.
[0024] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.
[0025] Example 1
[0026] A method for preparing cosmetic-grade azelaic acid comprises the following steps:
[0027] Step 1, C2-C9 monobasic saturated fatty acids (wherein nonanoic acid content is 45%, caproic acid content is 35%, and the rest are other C2-C9 monobasic saturated fatty acids) and butyl acetate are mixed in a mass ratio of 10:2 to obtain a mixed solvent, 1 kg of oleic acid (oleic acid content 75%) is added to 3 kg of the mixed solvent, and pulse ultrasonic treatment is performed for 30 minutes to obtain a mixed solution; wherein the specific parameters of the pulse ultrasound are: power 300 W, frequency 28 kHz, duty cycle 70%, ultrasonic working time 5 s, and intermittent time 5 s;
[0028] Step 2: Add the mixed solution obtained in step 1 into the ozonation reactor, maintain stirring at a speed of 100 r / min, and continuously introduce ozonated gas with an ozone content of 100 mg / L through the gas distributor. The ozonated gas flow rate is 1.5 m 3 / h, the reaction temperature is 25°C, until the ozone content in the ozonated gas introduced is consistent with the ozone content in the ozonated tail gas leaving the reaction system, the reaction is terminated, the obtained oleic acid ozonide is transferred to the oxidation reactor, and oxygen is introduced at an oxygen flow rate of 1m 3 / h, reaction temperature is 100℃, stirring reaction for 4h, sampling and analyzing the composition of oxidation solution every 0.5h, when the content of azelaic acid no longer increases, the reaction is terminated to obtain oxidation solution;
[0029] Step 3, using n-heptane as a solvent to crystallize the oxidation solution, the oxidation solution and n-heptane are mixed in a volume ratio of 5:2, and the program crystallization is as follows: the stirring speed is 80r / min, the temperature is increased to 60°C at a rate of 2°C / min, the temperature is kept constant for 0.5h, then the temperature is reduced to 50°C at a rate of 0.5°C / min, the temperature is kept constant for 1h, and then the temperature is reduced to 25°C at a rate of 1°C / min, and the temperature is kept constant for 0.5h; filter and dry to obtain crude azelaic acid, and the purity of the crude azelaic acid is 89.3% by gas chromatography;
[0030] Step 4: Mix crude azelaic acid and ethyl acetate in a mass ratio of 1:3, heat to 75°C, stir to dissolve, then cool to 45°C, stir to crystallize, filter, and dry to obtain cosmetic grade azelaic acid with a purity of 99.92%. Crystal test XRD, such as Figure 1 As shown, it is β-crystal form, and the yield is 92.5% (calculated based on oleic acid, the same below).
[0031] Example 2
[0032] This embodiment provides a method for preparing cosmetic-grade azelaic acid, wherein crude azelaic acid and ethyl acetate are mixed in a mass ratio of 1:4, and the remaining steps are the same as in Example 1, to obtain cosmetic-grade azelaic acid with a purity of 99.95%. The crystal test XRD shows that it is β-crystal, and the yield is 89.6%.
[0033] Example 3
[0034] This embodiment provides a method for preparing cosmetic grade azelaic acid, and step 4 is replaced by: mixing crude azelaic acid and pure water in a mass ratio of 1:3.5, heating to 90°C and stirring to dissolve, then cooling to 73°C and stirring to crystallize, filtering, and drying to obtain cosmetic grade azelaic acid, whose GC spectrum is as follows: Figure 3 As shown, the purity is 99.81%, and the crystal test XRD, such as Figure 2 As shown, it is α-crystal, and the yield is 90.5%; the remaining steps are the same as in Example 1.
[0035] Comparative Example 1
[0036] In this comparative example, crude azelaic acid and ethyl acetate were mixed in a mass ratio of 1:2, and the remaining steps were the same as those in Example 1. The final azelaic acid obtained had a purity of 99.02%, and the crystal test XRD showed that it was β-crystal, with a yield of 93.9%.
[0037] Comparative Example 2
[0038] In this comparative example, the crystallization temperature of step four is 43°C, and the remaining steps are the same as those in Example 1. The final obtained azelaic acid has a purity of 99.37%, and the crystal test XRD shows that it is β-crystal, with a yield of 93.6%.
[0039] Comparative Example 3
[0040] In this comparative example, the crystallization temperature of step four is 47°C, and the remaining steps are the same as those in Example 1. The final obtained azelaic acid has a purity of 99.90%, and the crystal test XRD shows that it is β-crystal. The yield is 84.9%, which is significantly lower than that in Example 1.
[0041] Comparative Example 4
[0042] In this comparative example, the crystallization temperature of step four is 72°C, and the remaining steps are the same as those in Example 3. The final obtained azelaic acid has a purity of 98.73%, and the crystal test XRD shows that it is α-crystal, with a yield of 91.4%.
[0043] Comparative Example 5
[0044] In this comparative example, the crystallization temperature of step four is 74°C, and the remaining steps are the same as those in Example 3. The final obtained azelaic acid has a purity of 99.91%, and the crystal test XRD shows that it is an α-crystal. The yield is 80.6%, which is significantly lower than that in Example 3.
[0045] Comparative Example 6
[0046] In this comparative example, crude azelaic acid and pure water are mixed in a mass ratio of 1:4, and the remaining steps are the same as those in Example 3. The final azelaic acid has a purity of 99.88%, and the crystal test XRD shows that it is an α-crystal. The yield is 83.3%, which is significantly lower than that in Example 3.
[0047] Comparative Example 7
[0048] In this comparative example, crude azelaic acid and pure water were mixed in a mass ratio of 1:3, and the remaining steps were the same as those in Example 3. The final azelaic acid had a purity of 98.33%, and the crystal test XRD showed that it was α-crystalline, with a yield of 91.3%.
[0049] Comparative Example 8
[0050] In this comparative example, the solvent n-heptane is not used in step three, the oxidizing liquid is directly crystallized, and the remaining steps are the same as those in Example 1. The purity of the obtained crude azelaic acid is 72.3%, which is lower than that in Example 1 (89.3%).
[0051] Comparative Example 9
[0052] In this comparative example, butyl acetate was not added to the mixed solvent, and the remaining steps were the same as those in Example 1. The purity of the obtained cosmetic-grade azelaic acid was 99.82%, and the yield was 90.5%.
[0053] Comparative Example 10
[0054] In this comparative example, pulse ultrasonic treatment was not performed, and the remaining steps were the same as those in Example 1. The purity of the obtained cosmetic-grade azelaic acid was 99.78%, and the yield was 90.0%.
[0055] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.
Claims
1. A method for preparing cosmetic grade azelaic acid, characterized in that: The following steps are involved: Step 1, uniformly mixing C2-C9 monobasic saturated fatty acids and butyl acetate to obtain a mixed solvent, adding oleic acid to the mixed solvent, and subjecting the mixed solvent to pulse ultrasonic treatment to obtain a mixed solution; Step 2, adding the mixed solution obtained in step 1 to an ozonation reactor to carry out an ozonation reaction, transferring the obtained oleic acid ozonate to an oxidation reactor to carry out an oxidation reaction to obtain an oxidized solution; Step 3, mixing the oxidation solution with n-heptane, performing program crystallization, filtering, and drying to obtain crude azelaic acid; Step 4: Mix the crude azelaic acid with a solvent, heat up and stir to dissolve, then cool down and stir to crystallize, filter, and dry to obtain cosmetic grade azelaic acid in different crystal forms.
2. The method for preparing cosmetic grade azelaic acid according to claim 1, characterized in that: In the step 1, among the monobasic saturated fatty acids of C2 to C9, the content of nonanoic acid is 45-55%, the content of caproic acid is 25-35%, and the rest are other monobasic saturated fatty acids of C2 to C9; the mass ratio of the monobasic saturated fatty acids of C2 to C9 to butyl acetate is 8-12:1-3; the mass ratio of oleic acid to the mixed solvent is 1:2-5.
3. The method for preparing cosmetic grade azelaic acid according to claim 1, characterized in that: In the step 1, the specific parameters of the pulse ultrasonic treatment are: power 100-500W, frequency 20-40kHz, duty cycle 50-80%, ultrasonic working time 3-12s, intermittent time 3-8s, and treatment time 20-40min.
4. The method for preparing cosmetic grade azelaic acid according to claim 1, characterized in that: In the step 2, the ozonation reaction is specifically as follows: stirring is maintained at a speed of 80 to 150 r / min, an ozonated gas with an ozone content of 80 to 120 mg / L is introduced, and the reaction temperature is 20 to 40° C. until the ozone content in the introduced ozonated gas is consistent with the ozone content in the ozonated tail gas leaving the reaction system, and the reaction is terminated.
5. The method for preparing cosmetic grade azelaic acid according to claim 1, characterized in that: In the step 2, the oxidation reaction is specifically as follows: oxygen is introduced, the reaction temperature is 80-120°C, sampling and analyzing the composition of the oxidation liquid every 0.5-1h during the reaction, and the reaction is terminated when the azelaic acid content no longer increases to obtain the oxidation liquid.
6. The method for preparing cosmetic grade azelaic acid according to claim 1, characterized in that: In the step 3, the volume ratio of the oxidizing liquid to n-heptane is 4-6:1-3.
7. The method for preparing cosmetic grade azelaic acid according to claim 1, characterized in that: In the step three, the programmed crystallization is specifically as follows: stirring speed 50-100 r / min, heating to 60°C at a rate of 1-3°C / min, keeping constant temperature for 0.2-1h, then cooling to 50°C at a rate of 0.2-1°C / min, keeping constant temperature for 0.5-1.5h, then cooling to 25°C at a rate of 0.5-1.5°C / min, keeping constant temperature for 0.2-1h.
8. The method for preparing cosmetic grade azelaic acid according to claim 1, characterized in that: In the step 4, the solvent is one of ethyl acetate and pure water.
9. The method for preparing cosmetic grade azelaic acid according to claim 8, characterized in that: The mass ratio of the crude azelaic acid to ethyl acetate is 1:3-4; the mass ratio of the crude azelaic acid to pure water is 1:3.
5.
10. The method for preparing cosmetic grade azelaic acid according to claim 9, characterized in that: In the step 4, when the solvent is ethyl acetate, the temperature is raised to 75°C and stirred to dissolve, then cooled to 45°C and stirred to crystallize, and the obtained cosmetic-grade azelaic acid is a β-crystalline form; when the solvent is pure water, the temperature is raised to 90°C and stirred to dissolve, then cooled to 73°C and stirred to crystallize, and the obtained cosmetic-grade azelaic acid is an α-crystalline form.