A method for purifying cosmetic-grade niacinamide

Abstract

The invention discloses a method for purifying cosmetic-grade nicotinamide, comprising the following steps: S1: batching: S2: heating: S3: segmented cooling: pouring the solution in S2 into a crystallization kettle for cooling operation; S4: centrifugation: S5: drying. The method for purifying cosmetic-grade nicotinamide solves the problem of excessively high nicotinic acid content in some nicotinamide products. Recrystallization of high-nicotinic acid nicotinamide is performed to extract nicotinamide with a nicotinic acid content of less than 50 ppm. The operation is simple, no special requirements are required for equipment, the process is mild, the process is controllable, no other additives are added except pure water, no pollution, environmentally friendly, suitable for transformation of industrial production, and increasing the diversity of industrial products.

Description

Technical Field

[0001] The invention relates to the technical field of niacinamide purification, and in particular to a method for purifying cosmetic-grade niacinamide. Background Art

[0002] The niacin content in the feed-grade niacinamide currently produced by the company is about 500ppm, while the niacin content in the niacinamide in the cosmetics market needs to be less than 100ppm, or even lower, to ensure that niacin does not irritate the skin. Therefore, it is necessary to perform recrystallization operations to purify high-nicotinic acid niacinamide to meet cosmetic grade requirements.

[0003] There is now a preparation method for reducing nicotinic acid in nicotinamide, characterized in that the method comprises the following steps: a) mixing nicotinamide with water and / or ethanol at a weight-to-volume ratio (g / ml) of 1:0.5-5, preferably 1:1-4, and more preferably 1:1-2; b) dropping or not dropping 1-10% by weight of an alkaline solution to a reaction system with a pH value of 6-9; the concentration of the alkaline solution is preferably 3-8% by weight, more preferably 4-6% by weight; the pH value of the reaction system is preferably 6.5-7.5; c) stirring for 0.5-5 hours, preferably 1-3 hours, and more preferably 1-2 hours; d) filtering, collecting solids, and drying. The invention process uses a variety of solvents, and the pH of the solution must be controlled during the process. When adjusting the pH, other impurities will also be introduced into the material, and the entire operation process is cumbersome. Summary of the invention

[0004] The purpose of the present invention is to provide a method for purifying cosmetic-grade niacinamide, which solves the problems in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for purifying cosmetic-grade niacinamide, comprising the following steps:

[0006] S1: Ingredients: 704.3g-722.5g of nicotinamide with high nicotinic acid content and 306.1g-580.8g of purified water are prepared into a nicotinamide solution with a concentration of 50-70% according to a certain ratio;

[0007] S2: Heating: The nicotinamide solution is first treated by ultrasound for 30 minutes, and nitrogen is introduced into the solution for 5 minutes during the ultrasound process. The nicotinamide solution is then added to a water bath, the top of the water bath is sealed, and the water bath is heated to 55-70°C to completely dissolve the nicotinamide in the solution;

[0008] S3: Stepwise cooling: Pour the solution in S2 into the crystallization kettle for cooling operation;

[0009] a. When the material temperature is ≤40°C, enter the first stage of the crystallization process, adjust the temperature difference between the incoming air temperature and the material temperature to maintain at 5°C, cool nicotinic acid and nicotinamide in the first stage, and maintain the temperature for 3 hours;

[0010] b. When the material temperature is ≤35°C, the second stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is regulated to be maintained at 5°C, and nicotinic acid and nicotinamide are cooled in the second stage;

[0011] c. When the material temperature is ≤30℃, enter the third stage of the crystallization process and wait until the air temperature drops to the same temperature as the material temperature;

[0012] d. When the material temperature is ≤25°C, the fourth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is adjusted from increasing to 11°C, and nicotinic acid and nicotinamide are cooled in the fourth stage. The precipitated materials are taken out and stored in a centrifuge dish;

[0013] e. When the material temperature is ≤20°C, the fifth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is increased to 16°C, and the nicotinic acid and nicotinamide are cooled in the fifth stage, and the temperature is maintained for 3 hours. The precipitated material is stored in a collection dish, and the crystallization process is completed;

[0014] S4: Centrifugation: Pour the material in the centrifuge dish in S3 into a centrifuge, and perform separation operation at a speed of 1300r / min to separate the water and crystals in the material;

[0015] S5: Drying: After the above centrifugation, the crystals are placed in a heating furnace and the temperature is raised to 40°C, and dried for 10 minutes to obtain a finished product, and the nicotinic acid crystals are collected.

[0016] Preferably, in S3, the solubility of nicotinamide is 1 g / mL, and the solubility of nicotinic acid is 1-5 g / 100 mL.

[0017] Preferably, in S3, in steps a to e, circulating air is used as a cooling process in the crystallization kettle, and a 100-mesh filter is provided at the bottom of the crystallization kettle, and crystals are extracted from the filter.

[0018] Preferably, in S3, in step d, crystals of nicotinamide are extracted from the filter screen, and in step e, crystals of nicotinic acid are extracted from the filter screen.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This method for purifying cosmetic-grade niacinamide solves the problem of excessive niacin content in some niacinamide products. The high-nicotinic acid niacinamide is recrystallized to extract niacinamide with a niacin content of less than 50ppm. The operation is simple, no special requirements are required for equipment, the process is mild, the process is controllable, no other additives except pure water, no pollution, environmentally friendly, suitable for transformation of industrial production, and increasing the diversity of industrial products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clarify the technical solutions in the embodiments of the present invention; it is clearly described in detail. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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.

[0023] In order to solve the problem in the prior art that multiple solvents are used, the pH of the solution must be controlled during the process, and other impurities will be introduced into the material while adjusting the pH. The entire operation process is cumbersome. The following technical methods are given. Please refer to Figure 1 ;

[0024] Embodiment 1:

[0025] A method for purifying cosmetic-grade niacinamide comprises the following steps:

[0026] Step 1: Ingredients: 704.3 g of niacinamide with high niacin content and 580.8 g of purified water are prepared into a 50% concentration niacinamide solution according to a certain ratio;

[0027] Step 2: Heating: The nicotinamide solution is first treated by ultrasound for 30 minutes, and nitrogen is introduced into the solution for 5 minutes during the ultrasound process. The nicotinamide solution is then added to a water bath, the top of the water bath is sealed, and the water bath is heated to 60° C. to completely dissolve the nicotinamide in the solution.

[0028] Step 3: Stepwise cooling: Pour the solution in step 2 into a crystallization kettle and cool it down. The solubility of nicotinamide is 1 g / mL, and the solubility of nicotinic acid is 1-5 g / 100 mL.

[0029] a. When the material temperature is ≤40°C, the first stage of the crystallization process is entered. The temperature difference between the incoming air temperature and the material temperature is regulated to be maintained at 5°C. Nicotinic acid and nicotinamide are cooled in the first stage and the temperature is maintained for 3 hours. The precipitated material is taken out and stored in a collection tank.

[0030] b. When the material temperature is ≤35°C, the second stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is regulated to be maintained at 5°C, and nicotinic acid and nicotinamide are cooled in the second stage;

[0031] c. When the material temperature is ≤30℃, enter the third stage of the crystallization process and wait until the air temperature drops to the same temperature as the material temperature;

[0032] d. When the material temperature is ≤25°C, the fourth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is adjusted from increasing to 11°C, and nicotinic acid and nicotinamide are cooled in the fourth stage. The precipitated materials are taken out and stored in a centrifuge dish;

[0033] e. When the material temperature is ≤20°C, the fifth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is increased to 16°C, and the nicotinic acid and nicotinamide are cooled in the fifth stage, and the temperature is maintained for 3 hours. The precipitated material is stored in a collection dish, and the crystallization process is completed;

[0034] In steps a to e, circulating air is used as a cooling process in the crystallization kettle, and a 100-mesh filter is provided at the bottom of the crystallization kettle to extract crystals from the filter.

[0035] In step d, nicotinamide crystals are extracted on the filter screen, and in step e, nicotinic acid crystals are extracted on the filter screen.

[0036] Step 4: Centrifugation: Pour the material in the centrifuge dish in step 3 into a centrifuge, and perform separation operation at a speed of 1300r / min to separate the water and crystals in the material to obtain 252.7g of wet material;

[0037] Step 5: Drying: After the above centrifugation, the crystals are placed in a heating furnace and the temperature is raised to 40°C. Dry for 10 minutes to obtain 226.2 g of a dry product, and collect nicotinic acid crystals. The finished product is tested for moisture content of 0.03%, nicotinamide concentration of 99.24%, nicotinic acid 36 ppm, and a yield of 32%.

[0038] Embodiment 2:

[0039] A method for purifying cosmetic-grade niacinamide comprises the following steps:

[0040] Step 1: Ingredients: 722.5g of niacinamide containing high niacin and 481.7g of purified water are prepared into a 60% concentration niacinamide solution according to a certain ratio;

[0041] Step 2: Heating: The nicotinamide solution is first treated by ultrasound for 30 minutes, and nitrogen is introduced into the solution for 5 minutes during the ultrasound process. The nicotinamide solution is then added to a water bath, the top of the water bath is sealed, and the water bath is heated to 55° C. to completely dissolve the nicotinamide in the solution.

[0042] Step 3: Stepwise cooling: Pour the solution in step 2 into a crystallization kettle and cool it down. The solubility of nicotinamide is 1 g / mL, and the solubility of nicotinic acid is 1-5 g / 100 mL.

[0043] a. When the material temperature is ≤40°C, the first stage of the crystallization process is entered. The temperature difference between the incoming air temperature and the material temperature is regulated to be maintained at 5°C. Nicotinic acid and nicotinamide are cooled in the first stage and the temperature is maintained for 3 hours. The precipitated material is taken out and stored in a collection tank.

[0044] b. When the material temperature is ≤35°C, the second stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is regulated to be maintained at 5°C, and nicotinic acid and nicotinamide are cooled in the second stage;

[0045] c. When the material temperature is ≤30℃, enter the third stage of the crystallization process and wait until the air temperature drops to the same temperature as the material temperature;

[0046] d. When the material temperature is ≤25°C, the fourth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is adjusted from increasing to 11°C, and nicotinic acid and nicotinamide are cooled in the fourth stage. The precipitated materials are taken out and stored in a centrifuge dish;

[0047] e. When the material temperature is ≤20°C, the fifth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is increased to 16°C, and the nicotinic acid and nicotinamide are cooled in the fifth stage, and the temperature is maintained for 3 hours. The precipitated material is stored in a collection dish, and the crystallization process is completed;

[0048] In steps a to e, circulating air is used as a cooling process in the crystallization kettle, and a 100-mesh filter is provided at the bottom of the crystallization kettle to extract crystals from the filter.

[0049] In step d, nicotinamide crystals are extracted on the filter screen, and in step e, nicotinic acid crystals are extracted on the filter screen.

[0050] Step 4: Centrifugation: Pour the material in the centrifuge dish in step 3 into a centrifuge, and perform separation operation at a speed of 1300r / min to separate the water and crystals in the material to obtain 275.6g of wet material;

[0051] Step 5: Drying: After the above centrifugation, the crystals are placed in a heating furnace and the temperature is raised to 40°C. Dry for 10 minutes to obtain 252.5 g of a dry product, and collect nicotinic acid crystals. The finished product is tested for moisture content of 0.03%, nicotinamide concentration of 99.29%, nicotinic acid 32 ppm, and a yield of 35%.

[0052] Embodiment three:

[0053] A method for purifying cosmetic-grade niacinamide comprises the following steps:

[0054] Step 1: Ingredients: 714.3 g of niacinamide containing high niacin and 306.1 g of purified water are prepared into a 70% concentration niacinamide solution according to a certain ratio;

[0055] Step 2: Heating: The nicotinamide solution is first treated by ultrasound for 30 minutes, and nitrogen is introduced into the solution for 5 minutes during the ultrasound process. The nicotinamide solution is then added to a water bath, the top of the water bath is sealed, and the water bath is heated to 55° C. to completely dissolve the nicotinamide in the solution.

[0056] Step 3: Stepwise cooling: Pour the solution in step 2 into a crystallization kettle and cool it down. The solubility of nicotinamide is 1 g / mL, and the solubility of nicotinic acid is 1-5 g / 100 mL.

[0057] a. When the material temperature is ≤40°C, the first stage of the crystallization process is entered. The temperature difference between the incoming air temperature and the material temperature is regulated to be maintained at 5°C. Nicotinic acid and nicotinamide are cooled in the first stage and the temperature is maintained for 3 hours. The precipitated material is taken out and stored in a collection tank.

[0058] b. When the material temperature is ≤35°C, the second stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is regulated to be maintained at 5°C, and nicotinic acid and nicotinamide are cooled in the second stage;

[0059] c. When the material temperature is ≤30℃, enter the third stage of the crystallization process and wait until the air temperature drops to the same temperature as the material temperature;

[0060] d. When the material temperature is ≤25°C, the fourth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is adjusted from increasing to 11°C, and nicotinic acid and nicotinamide are cooled in the fourth stage. The precipitated materials are taken out and stored in a centrifuge dish;

[0061] e. When the material temperature is ≤20°C, the fifth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is increased to 16°C, and the nicotinic acid and nicotinamide are cooled in the fifth stage, and the temperature is maintained for 3 hours. The precipitated material is stored in a collection dish, and the crystallization process is completed;

[0062] In steps a to e, circulating air is used as a cooling process in the crystallization kettle, and a 100-mesh filter is provided at the bottom of the crystallization kettle to extract crystals from the filter.

[0063] In step d, nicotinamide crystals are extracted on the filter screen, and in step e, nicotinic acid crystals are extracted on the filter screen.

[0064] Step 4: Centrifugation: Pour the material in the centrifuge dish in step 3 into a centrifuge, and perform separation operation at a speed of 1300r / min to separate the water and crystals in the material to obtain 281.2g of wet material;

[0065] Step 5: Drying: After the above centrifugation, the crystals were placed in a heating furnace and the temperature was raised to 40°C, and dried for 10 minutes to obtain 264.2g of dry product, and nicotinic acid crystals were collected. The finished product was tested for moisture 0.03%, nicotinamide concentration 99.14%, nicotinic acid 50ppm, and yield 37%.

[0066]

[0067] The process of the present invention mainly controls the initial concentration of recrystallization and utilizes the different solubility of nicotinamide at different temperatures to remove nicotinic acid. The whole process is simple and easy to operate, and other impurities will not be added to the material, and the environment will not be polluted.

[0068] The present invention solves the problem of excessively high nicotinic acid content in some nicotinamide products. Due to the low nicotinic acid content, the irritation reaction of cosmetics added with nicotinamide to the skin is reduced, and the application scope of nicotinamide is increased. By utilizing the change in the solubility of nicotinamide, high-nicotinic acid nicotinamide (niacin about 500ppm) is recrystallized to extract nicotinamide with a nicotinic acid content of less than 50ppm. The method for reducing nicotinic acid provided by nicotinamide is simple to operate, does not require special equipment requirements, is mild in the process, is controllable in the flow, does not add anything other than pure water, is pollution-free, is environmentally friendly, is suitable for transformation of industrial production, and increases the diversity of industrial products.

[0069] Nicotinamide has great prospects in cosmetics and skin clinical use, but a small amount of byproduct nicotinic acid in the finished nicotinamide product can cause irritation to the skin, and the user experience is very poor. Generally, the nicotinic acid content of nicotinamide products used in the cosmetics market needs to be less than 100ppm, or even lower, to ensure that nicotinic acid does not irritate the skin. The present invention uses nicotinamide with a high nicotinic acid content, reduces the nicotinic acid content in the nicotinamide by recrystallization, and purifies the nicotinamide with a high nicotinic acid content to meet the requirements of cosmetic grade nicotinamide.

[0070] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0071] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for purifying cosmetic-grade niacinamide, characterized in that: The following steps are involved: S1: Ingredients: 704.3g-722.5g of nicotinamide with high nicotinic acid content and 306.1g-580.8g of purified water are prepared into a nicotinamide solution with a concentration of 50-70% according to a certain ratio; S2: Heating: The nicotinamide solution is first treated by ultrasound for 30 minutes, and nitrogen is introduced into the solution for 5 minutes during the ultrasound process. The nicotinamide solution is then added to a water bath, the top of the water bath is sealed, and the water bath is heated to 55-70°C to completely dissolve the nicotinamide in the solution; S3: Stepwise cooling: Pour the solution in S2 into the crystallization kettle for cooling operation; S4: Centrifugation: Pour the material in the centrifuge dish in S3 into a centrifuge, and perform separation operation at a speed of 1300r / min to separate the water and crystals in the material; S5: Drying: After the above centrifugation, the crystals are placed in a heating furnace and the temperature is raised to 40°C, and dried for 10 minutes to obtain the finished product, and the nicotinic acid crystals are collected; For S3, the solubility of nicotinamide is 1 g / mL, and the solubility of nicotinic acid is 1-5 g / 100 mL; The operation of S3 is as follows: a. When the material temperature is ≤40°C, enter the first stage of the crystallization process, adjust the temperature difference between the incoming air temperature and the material temperature to maintain at 5°C, cool nicotinic acid and nicotinamide in the first stage, and maintain the temperature for 3 hours; b. When the material temperature is ≤35°C, the second stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is regulated to be maintained at 5°C, and nicotinic acid and nicotinamide are cooled in the second stage; c. When the material temperature is ≤30℃, enter the third stage of the crystallization process and wait until the air temperature drops to the same temperature as the material temperature; d. When the material temperature is ≤25°C, the fourth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is adjusted from increasing to 11°C, and nicotinic acid and nicotinamide are cooled in the fourth stage. The precipitated materials are taken out and stored in a centrifuge dish; e. When the material temperature is ≤20°C, the fifth stage of the crystallization process is entered, the temperature difference between the air temperature and the material temperature is increased to 16°C, and the nicotinic acid and nicotinamide are cooled in the fifth stage, and the temperature is maintained for 3 hours. The precipitated material is stored in a collection dish, and the crystallization process is completed; In S3, in steps a to e, circulating air is used as a cooling process in the crystallization kettle, and a 100-mesh filter is provided at the bottom of the crystallization kettle to extract crystals on the filter; By utilizing the change in the solubility of niacinamide, high-nicotinic acid niacinamide is recrystallized to extract niacinamide with a niacin content of less than 50 ppm.

2. A method for purifying cosmetic-grade niacinamide according to claim 1, characterized in that: With respect to S3, in step d, crystals of nicotinamide are extracted on the filter screen, and in step e, crystals of nicotinic acid are extracted on the filter screen.

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