Preparation method of cosmetic-grade 1, 3-butanediol

Abstract

The invention provides a preparation method of cosmetic grade 1, 3-butanediol. Industrial-grade 1, 3-butanediol is washed, extracted and rectified through a buffer solution, odorless 1, 3-butanediol is prepared, the content of 1, 3-butanediol is larger than 99.8%, key impurities are not detected, the product is free of peculiar smell, and the odorless 1, 3-butanediol can be applied to the field of cosmetics.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry and relates to a method for preparing cosmetic-grade 1,3-butanediol. Background Art

[0002] 1,3-Butanediol is a viscous, colorless, transparent, and odorless water-soluble liquid. Due to its low biological toxicity and good stability, 1,3-Butanediol is used as a cosmetic raw material. As a cosmetic raw material, it has moisturizing effects and antibacterial properties. Therefore, 1,3-Butanediol is used in shampoos, lotions, moisturizers and other products. When applying cosmetics, 1,3-Butanediol with a small odor is required. 1,3-Butanediol itself is almost odorless, but it will produce odor due to byproducts or impurities produced during the manufacturing process.

[0003] The main method for producing 1,3-butanediol is to condense acetaldehyde to obtain butanol aldehyde (3-hydroxybutyraldehyde), and then hydrogenate it. However, during the reaction, acetals or aldehydes are generated, which cause the product 1,3-butanediol to have an odor:

[0004]

[0005] CN 113557221 reported that the odor of the product was controlled by distillation, but the odor impurities were not completely removed, and the product still had odor when it was prepared into an aqueous solution. CN115400706 reported that the odor was removed by steam distillation, but the process was complicated and energy-intensive, which was not conducive to large-scale industrial production. CN114890869 reported that the odor was removed by esterification and extraction, but the reaction steps were complicated and new impurities were introduced, and the product was difficult to meet the requirements.

[0006] In summary, it is urgent to develop a process for deodorizing 1,3-butanediol to solve the deficiencies of existing technologies and processes and to be more conducive to industrial production. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for preparing 1,3-butanediol, wherein cosmetic-grade 1,3-butanediol is obtained by extraction and distillation. The method has the advantages of simple process, high product quality, and convenience for industrial production.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing cosmetic-grade 1,3-butanediol comprises: extracting and rectifying industrial-grade 1,3-butanediol to obtain cosmetic-grade 1,3-butanediol.

[0010] In the method of the present invention, the purity of the industrial-grade 1,3-butanediol is preferably above 99%.

[0011] In the method of the present invention, further, the industrial-grade 1,3-butanediol is first prepared with a buffer solution to form a mixed solution before extraction, and the concentration of 1,3-butanediol in the mixed solution is 10-90%, preferably 30-70%;

[0012] Furthermore, the pH value of the buffer solution is controlled at 3-7, and the buffer system is preferably an acetic acid / sodium acetate system, a sodium dihydrogen phosphate / disodium hydrogen phosphate system, a citric acid / sodium citrate system, a dipotassium hydrogen phosphate / potassium dihydrogen phosphate system, and further preferably a citric acid / sodium citrate system.

[0013] In the method of the present invention, further, the organic solvent used for extraction is a water-immiscible solvent, preferably toluene, cyclohexane, n-hexane, butyl acetate, ethyl acetate, n-hexane, methyltetrahydrofuran, methyl isobutyl ketone, and further preferably cyclohexane, methyltetrahydrofuran, methyl isobutyl ketone; the mass ratio of the amount of organic solvent used to the amount of water used is preferably 0.5-1;

[0014] Furthermore, during extraction, the mixed solution and the organic solvent can be mixed using a reaction kettle, a static mixer + a phase separation kettle, a rotating disk extraction tower, a packed tower, etc., preferably a rotating disk extraction tower and a packed tower.

[0015] In the method of the present invention, the aqueous phase after extraction is an aqueous solution of 1,3-butanediol, which is distilled to obtain cosmetic grade 1,3-butanediol;

[0016] Furthermore, during the distillation process, the oxygen content of the system is controlled to be less than 10 ppm.

[0017] The 1,3-butanediol prepared by the method of the present invention has a chromaticity of less than 10, a content of more than 99.8%, and no odor impurities are detected.

[0018] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0019] 1) The use of acidic buffer solution for extraction improves the removal effect of acetal impurities and avoids the deterioration of the product under acidic conditions;

[0020] 2) By controlling the oxidation amount of the distillation system, the generation of aldehyde impurities is avoided, and the product has low color and no odor. DETAILED DESCRIPTION

[0021] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0022] The reagents and solvents used in the present invention can be purchased from Aladdin Reagent Company.

[0023] Industrial grade 1,3-butanediol: Wanhua Chemical, 99.5%.

[0024] [Example 1]

[0025] 500 g of industrial-grade 1,3-butanediol was mixed with 500 g of aqueous solution (acetic acid / sodium acetate system, pH=6), and then the mixed aqueous solution and 300 g of cyclohexane were stirred in a reactor for 20 min. The mixture was allowed to stand for stratification, and the aqueous phase was purified by a distillation tower at a pressure of 10 kPa and 30 plates. The light components were taken from the top of the tower and the products were taken from the bottom of the tower. During the process, the oxygen content of the system was controlled to be <10 ppm. 480 g of 1,3-butanediol was obtained by distillation. The product had a purity of 99.92%, and impurity A, impurity B and butyraldehyde were not detected. The product had a color of 6 Hazen, and was recorded as sample 1.

[0026] [Example 2]

[0027] 5000g of industrial-grade 1,3-butanediol was mixed with 2000g of aqueous solution (sodium dihydrogen phosphate / disodium hydrogen phosphate system, pH=7), and then the aqueous solution and 1000g of methyl isobutyl ketone were extracted and separated in a rotary disc extraction tower. The aqueous phase entered a distillation tower for refining with a pressure of 5kPa and 30 plates. The light components were taken from the top of the tower and the products were taken from the bottom of the tower. During the process, the oxygen content of the system was controlled to be <10ppm. 4936g of 1,3-butanediol was obtained by distillation. The product purity was 99.87%, and impurity A, impurity B and butyraldehyde were not detected. The product color was 2Hazen, and it was recorded as sample 2.

[0028] [Example 3]

[0029] 5000g of industrial-grade 1,3-butanediol was mixed with 1000g of aqueous solution (citric acid / sodium citrate system, pH=4), and then the aqueous solution was extracted with 500g of methyltetrahydrofuran in a rotary disc extraction tower. The aqueous phase entered a distillation tower for refining with a pressure of 8kPa and 30 plates. The light components were taken from the top of the tower and the products were taken from the bottom of the tower. During the process, the oxygen content of the system was controlled to be <10ppm. 4918g of 1,3-butanediol was obtained by distillation. The product purity was 99.89%. Impurity A, impurity B and butyraldehyde were not detected. The product color was 2Hazen, and it was recorded as sample 3.

[0030] [Comparative Example 1]

[0031] Mix 500g of industrial-grade 1,3-butanediol with 500g of aqueous solution (sodium dihydrogen phosphate / disodium hydrogen phosphate system, pH=8), then stir the aqueous solution and 300g of cyclohexane in a reactor for 20min, let stand to separate the layers, and let the aqueous phase enter a distillation tower for refining at a pressure of 10kPa and 30 plates. The light components are taken from the top of the tower and the products are taken from the bottom of the tower. During the process, the oxygen content of the system is controlled to be <10ppm. 490g of 1,3-butanediol is obtained by distillation. The product purity is 99.85%, impurity A is 2ppm, impurity B is 3ppm, butyraldehyde is not detected, and the product color is 6Hazen, recorded as sample 4.

[0032] [Comparative Example 2]

[0033] 500g of industrial grade 1,3-butanediol was mixed with 500g of aqueous solution (acetic acid / sodium acetate system, pH=6), and then the aqueous solution and 300g of cyclohexane were stirred in a reactor for 20min. The mixture was allowed to stand for stratification and the aqueous phase was sent to a distillation tower for refining at a pressure of 10kPa and 30 plates. The light components were taken from the top of the tower and the products were taken from the bottom of the tower. During the process, the oxygen content in the system was 40ppm. 460g of 1,3-butanediol was obtained by distillation. The product had a purity of 99.82%, impurities A and impurity B were not detected, the butyraldehyde content was 1ppm, and the product color was 16Hazen. It was recorded as sample 5.

[0034] The prepared samples were prepared into aqueous solutions of different concentrations for odor testing. Each sample was identified by 10 people. The results are shown in the following table.

[0035]

[0036]

[0037] It can be seen from the test results of the above embodiments and comparative examples that the method of the present invention obtains cosmetic 1,3-butanediol by washing, extracting and distilling with an acidic buffer solution, which has the significant advantages of simple operation and easy industrialization compared with the existing technology in the comparative example.

[0038] The above description is only an example of the implementation method of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing cosmetic grade 1,3-butanediol, characterized in that: After industrial-grade 1,3-butanediol is extracted and distilled, cosmetic-grade 1,3-butanediol is obtained; Wherein, before extraction, the industrial-grade 1,3-butanediol is firstly prepared into a mixed solution with a buffer solution, and the pH value of the buffer solution is 3-7.

2. The preparation method according to claim 1, characterized in that: The buffer solution is at least one of an acetic acid / sodium acetate system, a sodium dihydrogen phosphate / disodium hydrogen phosphate system, a citric acid / sodium citrate system, and a dipotassium hydrogen phosphate / potassium dihydrogen phosphate system.

3. The preparation method according to claim 1 or 2, characterized in that: The concentration of 1,3-butanediol in the mixed solution is 10-90wt%.

4. The preparation method according to claim 3, characterized in that: The concentration of 1,3-butanediol in the mixed solution is 30-70wt%.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The organic solvent used for extraction is a solvent that is immiscible with water.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The organic solvent used for extraction is at least one of toluene, cyclohexane, n-hexane, butyl acetate, ethyl acetate, n-hexane, methyltetrahydrofuran and methyl isobutyl ketone.

7. The preparation method according to any one of claims 1 to 6, characterized in that: During the distillation process, the oxygen content in the system is controlled to be less than 10ppm.

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