High-efficiency and low-cost acidifying and purifying method for sodium p-xylylene dichorsulfonate crude product

Abstract

The invention discloses a high-efficiency and low-cost acidifying and purifying method for a crude product of sodium p-xylylene dichorsulfonate, and belongs to the technical field of production and purification of fine chemicals. According to the scheme, the crude product of sodium p-xylylene dichorsulfonate and a mixed solvent of water, methanol, ethanol and butanol are stirred at a low temperature, hydrogen chloride gas is introduced, and the crude product of sodium p-xylylene dichorsulfonate is acidified and purified; white solids are separated out after suspension clarification, sodium chloride solids are filtered at low temperature, water, methanol, ethanol and butanol are recycled from mother liquor, and a product with the HPLC purity larger than 99% is obtained. The purification method is low in raw material cost, simple and easy to implement and low in equipment requirement, hydrogen chloride is fully utilized, and the by-product NaCl is completely separated.

Description

Technical Field

[0001] The present invention relates to a method for acidifying and purifying crude sodium terephthalylidene dicamphorsulfonate with high efficiency and low cost, belonging to the technical field of production and purification of fine chemicals. Background Art

[0002] Ultraviolet rays of different bands include ultraviolet UVA (320 nm to 400 nm) and ultraviolet UVB (290 nm to 320 nm), and ultraviolet UVA among them accounts for more than 90% of ultraviolet rays. Ultraviolet UVA penetrates the skin and affects cells, destroys collagen and elastic fibers, accelerates the skin aging process, manifested as rough skin, wrinkles and pigmentation. It can even cause damage to the surface of the eyes, such as keratitis and conjunctivitis, and long-term exposure may also lead to cataracts and macular degeneration, inhibit the immune function of the skin, reduce the body's defense ability against bacteria, viruses and tumors, and may increase the risk of skin infections and other diseases.

[0003] Terephthalylidene dicamphorsulfonic acid is one of the most effective chemical components for filtering ultraviolet UVA at present, and has obtained the recognition of the US FDA and has a wide range of uses in the cosmetic field. Terephthalylidene dicamphorsulfonic acid belongs to a water-soluble chemical sunscreen, has good spreading properties and good skin feel. Therefore, cosmetics containing terephthalylidene dicamphorsulfonic acid are easy to wash, which is beneficial to keeping the skin clean.

[0004] At present, terephthalylidene dicamphorsulfonic acid is mainly prepared by the following method: terephthalaldehyde reacts with camphorsulfonic acid under the condition of sodium methoxide, and the product formed is a sodium salt, which needs to be further acidified before being used in cosmetics. As follows:

[0005]

[0006] For example, CN106831503A, CN110156642A, etc. have all disclosed corresponding preparation methods, which use hydrochloric acid to acidify terephthalylidene dicamphorsulfonic acid hydrochloride to obtain terephthalylidene dicamphorsulfonic acid, as follows:

[0007]

[0008] This type of scheme will use a large amount of hydrochloric acid, so a large amount of waste acid solution will be generated in the process, resulting in a huge environmental protection pressure. Moreover, the by-product NaCl also has the characteristic of good water solubility like terephthalylidene dicamphorsulfonic acid, and directly using the hydrochloric acid acidification process will bring NaCl into the product. If the by-product NaCl cannot be removed completely, the residue will affect the use of the product in cosmetics.

[0009] Regarding the problem of by-product NaCl residue, existing patented technologies such as CN108698986B, CN112566896B, CN115784942A, etc. utilize a new technology of acidifying and purifying benzylidene camphor sulfonate with ion exchange resins, that is, converting benzylidene camphor sulfonate into benzylidene camphor sulfonic acid by using cation exchange resin, cation exchange resin and anion exchange resin or cation exchange fiber, and then recycling the resin for reuse. This conversion method has the remarkable feature of high conversion rate and can ensure that NaCl can be completely separated. However, a large amount of expensive resins are used in the resin exchange method. Although the resin can be recycled, it still makes the production cost high. Moreover, the scale of use of ion exchange resins in production is limited, which causes difficulties in process amplification. Summary of the Invention

[0010] Aiming at the deficiencies in the above-mentioned existing technologies, the present invention provides a method for acidifying and purifying crude sodium benzylidene camphor sulfonate with high efficiency and low cost. By utilizing the dissolution characteristics of NaCl, benzylidene camphor sulfonic acid and sodium benzylidene camphor sulfonate in a mixed solvent of water, methanol, ethanol and butanol at different temperatures and pH values, and under the set ratio and temperature conditions, without directly using hydrochloric acid, hydrogen chloride gas is introduced on the premise of only trace water in the system, so that NaCl can precipitate while benzylidene camphor sulfonic acid dissolves, thereby achieving the separation and purification effect. This purification method has low raw material cost, is simple and easy to operate, has low requirements for equipment, and can achieve a product recovery rate of ≥96% and a purity of ≥99%, and the NaCl recovery rate is ≥99%.

[0011] In order to achieve the above object, the technical solution of the present invention is as follows:

[0012] A method for acidifying and purifying crude sodium benzylidene camphor sulfonate with high efficiency and low cost, which comprises the following steps:

[0013] S1. Mix the crude sodium benzylidene camphor sulfonate with water, methanol, ethanol and butanol solvents, and stir at -10°C to 0°C for 100 min to 120 min to form a suspension. Among them, the mass-volume ratio of the crude sodium benzylidene camphor sulfonate to the solvent is 1 g: 6 - 10 mL, and the volume ratio of water, methanol, ethanol and butanol in the solution is 0 - 2.0: 0 - 15.0: 0 - 25.0: 0 - 5.0;

[0014] S2. While stirring at -10°C to 0°C, introduce hydrogen chloride gas into the suspension. Stop introducing hydrogen chloride gas when the suspension is completely dissolved and clarified.

[0015] S3. Heat up to 10°C to 20°C, stir to precipitate solids, stir for 80 min to 100 min, and filter to obtain solid NaCl.

[0016] S4. Heat the mother liquor to 40°C - 50°C, stir and concentrate it to half of its original volume to precipitate NaCl product, continue stirring for 50 min - 60 min, and filter to obtain terephthalylidene dicamphor sulfonic acid with an HPLC purity of 99% or above.

[0017] The following conditions are optimized in the overall scheme: the HPLC purity of the crude terephthalylidene dicamphor sulfonate in step S1 is 80% - 95%; the solvent in step S1 is water, two or more of methanol, ethanol, and butanol; the water in the solution in step S1 is deionized water; the HPLC purity of methanol, ethanol, and butanol is ≥99%; the purity of the hydrogen chloride gas in step S2 is ≥99%.

[0018] Advantages of the present invention: The product is purified through an innovative process of dissolution - precipitation - concentration. Utilizing the solubility characteristics of NaCl, terephthalylidene dicamphor sulfonic acid, and terephthalylidene dicamphor sulfonate in mixed solvents such as water, methanol, ethanol, and butanol at different temperatures and pH values, under the set ratio and temperature conditions, without directly using hydrochloric acid, ensuring that hydrogen chloride gas is introduced on the premise of only trace amounts of water in the system, so that NaCl can precipitate while terephthalylidene dicamphor sulfonic acid dissolves, thereby achieving the separation and purification effect. This purification method has low raw material costs, is simple and easy to operate, has low requirements for equipment, makes full use of hydrogen chloride, and can completely separate the by - product NaCl. After acidifying and purifying the crude terephthalylidene dicamphor sulfonate, a product recovery rate of ≥96% and a purity of ≥99% can be achieved, and the NaCl recovery rate is ≥99%. Specific Embodiments

[0019] The present invention will be further described in detail below with specific embodiments.

[0020] Example 1:

[0021] Add 50 g of crude terephthalylidene dicamphor sulfonate with a purity of 80% and 400 mL of solvent to a 1000 - ml three - necked round - bottom flask. The volume ratio in the solution is: water: methanol: ethanol: butanol = 2:15:25:5. Stir at - 10°C for 100 min to form a suspension; then, while continuing to stir at - 10°C, introduce hydrogen chloride gas into the suspension. Stop introducing hydrogen chloride gas when the suspension is completely dissolved and clarified; after the gas introduction ends, raise the temperature to 20°C, stir to precipitate solids, stir for 80 min, and filter to obtain 4.01 g of NaCl solid with a recovery rate of 99.1%; heat the mother liquor to 40°C, stir and concentrate it to a volume of 400 mL, precipitate the product, stir for 40 min, and filter to obtain 35.2 g of terephthalylidene dicamphor sulfonic acid with a recovery rate of 95.3%, and its mass content measured by HPLC is 99.54%.

[0022] Example 2

[0023] In a 1000 ml three-necked round-bottom flask, 50 g of crude sodium terephthalylidene dicamphor sulfonate with a purity of 90% and 300 mL of solvent were added. The volume ratio in the solution was: water: methanol: ethanol = 1:10:20. It was stirred at -5 °C for 110 min to form a suspension; then, while stirring at -5 °C, hydrogen chloride gas was introduced into the suspension. When the suspension was completely clarified, the introduction of hydrogen chloride gas was stopped; after the gas introduction ended, the temperature was raised to 15 °C, and a solid was precipitated with stirring for 90 min. 4.49 g of NaCl solid was obtained by filtration, with a recovery rate of 99.1%; the mother liquor was heated to 45 °C and concentrated to a volume of 150 mL with stirring to precipitate the product, stirred for 50 min, and 40.8 g of terephthalylidene dicamphor sulfonic acid was obtained by filtration and separation, with a recovery rate of 98.2%. The mass content measured by HPLC was 99.85%.

[0024] Example 3

[0025] In a 1000 ml three-necked round-bottom flask, 50 g of crude sodium terephthalylidene dicamphor sulfonate with a purity of 95% and 500 mL of solvent were added. The volume ratio in the solution was: water: methanol: ethanol: butanol = 1:8:25:3. It was stirred at 0 °C for 120 min to form a suspension; then, while stirring at 0 °C, hydrogen chloride gas was introduced into the suspension. When the suspension was completely clarified, the introduction of hydrogen chloride gas was stopped; after the gas introduction ended, the temperature was raised to 10 °C, and a solid was precipitated with stirring for 100 min. 4.67 g of NaCl solid was obtained by filtration, with a recovery rate of 99.0%; the mother liquor was heated to 50 °C and concentrated to a volume of 250 mL with stirring to precipitate the product, stirred for 45 min, and 42.3 g of terephthalylidene dicamphor sulfonic acid was obtained by filtration and separation, with a recovery rate of 96.4%. The mass content measured by HPLC was 99.53%.

[0026] Example 4

[0027] In a 1000 ml three-necked round-bottom flask, 50 g of crude sodium terephthalylidene dicamphor sulfonate with a purity of 95% and 500 mL of solvent were added. The volume ratio in the solution was: water: ethanol: butanol = 1:20:2. It was stirred at 0 °C for 120 min to form a suspension; then, while stirring at 0 °C, hydrogen chloride gas was introduced into the suspension. When the suspension was completely clarified, the introduction of hydrogen chloride gas was stopped; after the gas introduction ended, the temperature was raised to 10 °C, and a solid was precipitated with stirring for 100 min. 4.71 g of NaCl solid was obtained by filtration, with a recovery rate of 99.0%; the mother liquor was heated to 50 °C and concentrated to a volume of 250 mL with stirring to precipitate the product, stirred for 45 min, and 41.9 g of terephthalylidene dicamphor sulfonic acid was obtained by filtration and separation, with a recovery rate of 95.5%. The mass content measured by HPLC was 99.87%.

[0028] Example 5

[0029] Add 50 g of the crude product of sodium terephthalylidene dicamphorsulfonate with a purity of 95% and 500 mL of solvent into a 1000 mL three-necked round-bottom flask. The volume ratio in the solution is: water: methanol: ethanol = 0.5:15:25. Stir at 0 °C for 120 min to form a suspension; then, while stirring at 0 °C, pass hydrogen chloride gas into the suspension. When the suspension is completely clarified, stop passing hydrogen chloride gas; after the gas passing ends, raise the temperature to 10 °C, stir to precipitate solids, stir for 100 min, and filter to obtain 4.69 g of NaCl solid with a recovery rate of 99.0%; heat the mother liquor to 50 °C, concentrate it to a volume of 250 mL while stirring to precipitate the product, stir for 45 min, and filter and separate to obtain 42.7 g of terephthalylidene dicamphorsulfonic acid with a recovery rate of 97.3%, and its mass content is measured by HPLC to be 99.74%.

[0030] Example 6

[0031] Add 50 g of the crude product of sodium terephthalylidene dicamphorsulfonate with a purity of 95% and 500 mL of solvent into a 1000 mL three-necked round-bottom flask. The volume ratio in the solution is: water: methanol: butanol = 0.5:15:5. Stir at 0 °C for 120 min to form a suspension; then, while stirring at 0 °C, pass hydrogen chloride gas into the suspension. When the suspension is completely clarified, stop passing hydrogen chloride gas; after the gas passing ends, raise the temperature to 10 °C, stir to precipitate solids, stir for 100 min, and filter to obtain 4.70 g of NaCl solid with a recovery rate of 99.0%; heat the mother liquor to 50 °C, concentrate it to a volume of 250 mL while stirring to precipitate the product, stir for 45 min, and filter and separate to obtain 42.9 g of terephthalylidene dicamphorsulfonic acid with a recovery rate of 97.9%, and its mass content is measured by HPLC to be 99.78%.

[0032] The technical solutions provided by the embodiments of the present invention have been introduced in detail above. Specific examples are used herein to elaborate on the principles and implementation manners of the embodiments of the present invention. The descriptions of the above embodiments are only applicable to help understand the principles of the embodiments of the present invention; at the same time, for those of ordinary skill in the art, according to the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for acidifying and purifying a crude product of sodium terephthalidene dicamphor sulfonic acid salt with high efficiency and low cost, characterized in that: The following steps are included: S1. Stir the crude sodium salt of terephthalylidene dicamphor sulfonic acid with water, methanol, ethanol, and butanol solvents at -10°C to 0°C for 100min to 120min to form a suspension, wherein the mass volume ratio of the crude sodium salt of terephthalylidene dicamphor sulfonic acid to the solvent is 1g:6-10mL, and the volume ratio of water, methanol, ethanol, and butanol in the solution is 0-2.0:0-15.0:0-25.0:0-5.0; S2. While stirring at -10°C to 0°C, introduce hydrogen chloride gas into the suspension, and stop introducing hydrogen chloride gas when the suspension is completely dissolved; S3, heating to 10°C to 20°C, stirring to precipitate solid, stirring for 80min to 100min, and filtering to obtain NaCl solid; S4. Raise the temperature of the mother liquor to 40°C to 50°C, stir and concentrate to half the volume of the mother liquor, precipitate the NaCl product, continue stirring for 50min to 60min, filter and separate to obtain terephthalylidene dicamphor sulfonic acid with HPLC purity of 99% or more.

2. A method for acidifying and purifying a crude product of sodium terephthalylidene dicamphor sulfonic acid salt with high efficiency and low cost according to claim 1, characterized in that: The HPLC purity of the crude sodium salt of terephthalylidene dicamphor sulfonic acid in step S1 is 80% to 95%.

3. A method for acidifying and purifying a crude product of sodium terephthalylidene dicamphor sulfonic acid salt with high efficiency and low cost according to claim 1, characterized in that: The solvent in step S1 is water, two or more kinds of methanol, ethanol and butanol.

4. A method for acidifying and purifying a crude product of sodium terephthalylidene dicamphor sulfonic acid salt with high efficiency and low cost according to claim 1, characterized in that: The water in the solution in step S1 is deionized water; the HPLC purity of methanol, ethanol and butanol is ≥99%.

5. The method for acidifying and purifying a crude product of sodium terephthalylidene dicamphor sulfonic acid salt with high efficiency and low cost according to claim 1, characterized in that: The purity of the hydrogen chloride gas in step S2 is ≥99%.

Images