阅读说明：本技术 安赛蜜的精制方法 (Refining method of acesulfame potassium ) 是由 王从春 陈永旭 沈孝峰 陈朝晖 沈东东 于 2020-09-21 设计创作，主要内容包括：本申请提供一种安赛蜜的精制方法,包括：向含有安赛蜜粗产品溶液中加入双氧水和活性炭,在第一预设温度下保持第一预设时间,经过滤得到安赛蜜母液；将安赛蜜母液浓缩至预设浓度,得到浓缩溶液,将浓缩溶液在第二预设温度下静置第二预设时间,以形成安赛蜜晶核,得到含晶核溶液；将含晶核溶液进行程序降温,获得含有大量安赛蜜晶体的溶液；将含有大量安赛蜜晶体的溶液离心、水洗、干燥,获得安赛蜜晶体产品。本申请的有益效果在于：通过控制结晶过程和工艺,得到了高品质、高纯度的结晶产品,杂质含量少,显著提高了安赛蜜晶体的纯度和质量；且工艺简单,条件温和可控,对设备和人员技术要求低,非常适合大规模工业化生产。(The application provides a refining method of acesulfame potassium, which comprises the following steps: adding hydrogen peroxide and activated carbon into the crude product solution containing the acesulfame potassium, keeping the temperature for a first preset time, and filtering to obtain an acesulfame potassium mother solution; concentrating the acesulfame-K mother liquor to a preset concentration to obtain a concentrated solution, and standing the concentrated solution at a second preset temperature for a second preset time to form acesulfame-K crystal nuclei to obtain a crystal nucleus-containing solution; carrying out programmed cooling on the solution containing the crystal nucleus to obtain a solution containing a large amount of acesulfame potassium crystals; and centrifuging, washing and drying the solution containing a large amount of acesulfame potassium crystals to obtain an acesulfame potassium crystal product. The beneficial effect of this application lies in: by controlling the crystallization process and the technology, a high-quality and high-purity crystallized product is obtained, the impurity content is low, and the purity and the quality of the acesulfame potassium crystal are obviously improved; and the method has the advantages of simple process, mild and controllable conditions, low technical requirements on equipment and personnel, and suitability for large-scale industrial production.)

1. A refining method of acesulfame potassium is characterized by comprising the following steps:

a pretreatment step: adding hydrogen peroxide and activated carbon into the crude product solution containing the acesulfame potassium, keeping the temperature for a first preset time, and filtering to obtain an acesulfame potassium mother solution;

a crystal nucleus forming step: concentrating the acesulfame-K mother liquor to a preset concentration to obtain a concentrated solution, and standing the concentrated solution at a second preset temperature for a second preset time to form acesulfame-K crystal nuclei to obtain a crystal nucleus-containing solution;

a crystal formation step: carrying out programmed cooling on the crystal nucleus-containing solution to obtain a solution containing a large amount of acesulfame potassium crystals;

refining: and centrifuging, washing and drying the solution containing a large amount of acesulfame potassium crystals to obtain an acesulfame potassium crystal product.

2. The method according to claim 1, wherein the amount of the hydrogen peroxide by mass is 0.1-10 wt%, preferably 0.5-2 wt% of the total mass of the crude acesulfame potassium solution;

the mass amount of the activated carbon is 0.1-5 wt%, preferably 0.2-4 wt% of the total mass of the crude product solution of the acesulfame potassium.

3. The method according to claim 1, wherein, in the pre-treatment step, the first preset temperature is 40 ℃ to 90 ℃; the first preset time is 1-8 h.

4. The method according to claim 1, wherein in the nucleation step, the concentration is performed by reduced pressure distillation at a temperature of 45 to 80 ℃, preferably 55 to 65 ℃; the pressure of the reduced pressure distillation is maintained between-95 KPa and-101 KPa, and the time of the reduced pressure distillation is 10min to 12 min.

5. The method according to claim 1, wherein in the nucleation step, the pre-concentration is performed to a solid phase content of 30 to 90 wt%, preferably 40 to 80 wt%, of the total mass of the acesulfame k mother liquor.

6. The method according to claim 1, characterized in that, in the nucleation step, the second preset temperature is 40-70 ℃, preferably 45-60 ℃;

the second preset time is 0.1-4 h; preferably 0.5h to 2 h.

7. The method of claim 1, wherein in the crystal formation step, the programmed temperature reduction is: firstly, cooling to 43-45 ℃ from a second preset temperature at the speed of 1 ℃/10-60 min, and keeping for 0.5-8 h; then cooling to 8-12 ℃ at the speed of 1 ℃/10-60 min.

8. The method of claim 7, wherein in the crystal formation step, the programmed temperature reduction is: firstly, cooling to 45 ℃ from a second preset temperature at the speed of 1 ℃/10-60 min, and keeping for 0.5-8 h; then cooling to 10 ℃ at the speed of 1 ℃/10-60 min.

9. acesulfame-K crystals obtained by the refining process according to any one of claims 1 to 8, having a purity of higher than 99.20%, an organic impurity content of less than 10ppm and a moisture content of less than 0.3 wt%.

10. An acesulfame-K crystal according to claim 9, wherein the most intense three sets of diffraction peak positions of the acesulfame-K crystal before drying are 8.8 ± 0.2, 17.3 ± 0.2 and 28.8 ± 0.2, respectively;

after drying, the peak intensity of XRD of the acesulfame potassium crystal is weaker than that of the acesulfame potassium crystal before drying, and at this time, the position of the strongest peak is 8.8 +/-0.2, and the position of the second strongest peak is 17.3 +/-0.2.

Technical Field

The application belongs to the field of fine chemical manufacturing, and particularly relates to a refining method of acesulfame potassium.

Background

The refining process in the traditional acesulfame potassium production process is to separate mother liquor obtained by organic phase, commonly called sugar water, and obtain crude sugar (Jiangyu, the synthesis research of acesulfame potassium serving as a sweetening agent, 2008, 35 and 9 in scientific and technological innovation guide) through a series of steps such as decoloration, heating concentration, freezing crystallization, centrifugal separation and the like; and recrystallizing the crude sugar at least twice to obtain the qualified acesulfame potassium product. The biggest difficulty of the prior acesulfame potassium production refining process is that organic impurities generated in the production process are brought to a final product from an initial sugar, so that the content of the organic impurities in the sugar exceeds the standard, the color of the product is darker, and the problems of the purity and the quality of the product always trouble production enterprises. Thus, the purification process of acesulfame k determines the purity and quality of the final product. The analysis reasons include that firstly, the purification and decoloration processes of organic impurities in the sugar water cannot meet the requirements, and secondly, the control of the crystallization step is not in place, so that the purity, the production efficiency and the yield of the product are not satisfactory, further the production cost of the product is influenced, and the problems of poor color, incomplete crystallization, high impurity content, limited purity, low yield and the like of the sugar water are caused.

The prior purification process from sugar water to qualified products is intermittent production, the multiple crystallization energy consumption is high, the resource waste is serious, the manual operation is complicated, the production cost is high, the reaction equipment is complex and various, the temperature change is large, and the service life of the equipment is short; the production is intermittent, the utilization rate of the device is low, the impurity content in the finished product is easy to exceed the standard, the product quality can not meet the market requirement, and the market value of the product is seriously influenced.

It should be noted that the statements herein merely provide background information related to the present application and may not necessarily constitute prior art.

Content of application

In view of the above problems, the present application has been made to provide a refining method of acesulfame potassium which overcomes or at least partially solves the above problems.

According to an aspect of the present application, there is provided a refining method of acesulfame potassium, comprising:

a pretreatment step: adding hydrogen peroxide and active carbon into the crude product solution containing the acesulfame potassium, and keeping the solution at a first preset temperature for a first preset time to obtain an acesulfame potassium mother solution;

a crystal nucleus forming step: concentrating the acesulfame-K mother liquor to a preset concentration to obtain a concentrated solution, and standing the concentrated solution at a second preset temperature for a second preset time to form acesulfame-K crystal nuclei to obtain a crystal nucleus-containing solution;

a crystal formation step: carrying out programmed cooling on the crystal nucleus-containing solution to obtain a solution containing a large amount of acesulfame potassium crystals;

refining: and centrifuging, washing and drying the solution containing a large amount of acesulfame potassium crystals to obtain an acesulfame potassium crystal product.

According to another aspect of the present application, there is provided an acesulfame potassium crystal which is prepared by the above refining method, and which has a purity of more than 99.20%, an organic impurity content of less than 10ppm, and a moisture content of less than 0.3 wt%.

The beneficial effect of this application lies in: by controlling the pretreatment step, the solution to be crystallized (namely sugar water) is subjected to oxidation decoloration treatment, so that the content of organic impurities in the primary sugar of acesulfame is reduced, and the defects of low product purity, yellow color and the like caused by bringing the organic impurities into the final crystallized product are avoided; in addition, the crystallization process and the process are controlled, so that a high-quality and high-purity crystallized product is obtained, the impurity content is low, and the purity and the quality of the acesulfame potassium crystal are obviously improved; and the method has the advantages of simple process, mild and controllable conditions, low technical requirements on equipment and personnel, and suitability for large-scale industrial production.

The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1: XRD patterns of the acesulfame k crystals prepared in example 1 and comparative example 1 are shown.

Detailed Description

Exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The idea of the application is that oxidation and decoloration treatment is carried out on the solution to be crystallized of acesulfame potassium (namely sugar water) through oxidation-reduction reaction and physical adsorption, so that the content of organic impurities in the primary sugar is reduced; and then forming crystal nuclei through concentration and heat preservation, and then fully crystallizing by utilizing a secondary nucleation process to obtain the acesulfame potassium crystal with good crystal form and high purity, thereby obviously reducing the peritectic impurity content and improving the purity of the product.

The refining method of acesulfame potassium provided by the application comprises the following steps: a pretreatment step: adding hydrogen peroxide and active carbon into the solution containing the crude acesulfame potassium product, keeping the temperature for a first preset time, and filtering to obtain an acesulfame potassium mother solution.

In the production process of acesulfame potassium, crystallization purification is a very important step, which is directly related to the quality problem of the product, and the crude solution of acesulfame potassium obtained in the production process of acesulfame potassium contains a large amount of organic impurities, such as acetoacetamide, etc., and some colored impurities, such as diacetyl triphenol generated after dimerization of diketene and compounds of trimeric tetrapolyphenylpropanol, etc. (E.Marcus and J.K.Chan, Novel fermentation Products of Dikeen, J.org.Chem.1967,32,9, 2881-. In the pretreatment step, impurities such as acetoacetamide, polymers and the like are treated by hydrogen peroxide, the hydrogen peroxide and the acetoacetamide, the polymers and the like in organic impurities undergo redox reaction to generate hydrophilic carboxylic acid and other substances, and the hydrophilic carboxylic acid and other substances are remained in the solution and cannot enter a final product in the crystallization refining process.

For some colored impurities, the present application uses activated carbon, which is a specially treated carbon, organic raw materials (shells, coal, wood, etc.) are heated in the absence of air to reduce non-carbon components, a process called carbonization, and then react with gas to erode the surface and produce a structure with developed micropores, a process called activation. Since the activation process is a microscopic process, i.e., the surface erosion of a large amount of molecular carbides is a point-like erosion, the surface of the activated carbon is caused to have countless fine pores. The diameter of the micropores on the surface of the activated carbon is mostly between 2nm and 50nm, even a small amount of activated carbon has huge surface area, and the surface area of each gram of activated carbon is 500m²～1500m²The application utilizes the huge surface area of active carbon to adsorb the colored impurity in the solution to avoided colored impurity to enter into final crystallization product, improved the purity and the color grade of product.

A crystal nucleus forming step: concentrating the acesulfame-K mother liquor to a preset concentration to obtain a concentrated solution, and standing the concentrated solution at a second preset temperature for a second preset time to form acesulfame-K crystal nuclei to obtain a crystal nucleus-containing solution.

A crystal formation step: and carrying out programmed cooling on the crystal nucleus-containing solution to obtain a solution containing a large amount of acesulfame potassium crystals.

The crystallization process of the acesulfame potassium refining method provided by the application is divided into two steps, namely a crystal nucleus forming step and a crystallization forming step, wherein the crystal nucleus forming step is used for forming a small amount of crystal nuclei in the acesulfame potassium mother liquor through controlling conditions, and the crystal nuclei are used as crystal seeds in the crystallization forming step to provide a basis for the large-scale growth of crystals.

In the prior art, acesulfame potassium crystals are prepared by a repeated recrystallization method, and the generated crystals have many defects, such as low product purity, low yield, complex process, high technical requirements on equipment and personnel and the like.

Refining: and centrifuging, washing and drying the obtained solution containing a large amount of acesulfame potassium crystals to obtain an acesulfame potassium crystal product.

Finally, the acesulfame potassium crystal product with high purity and high yield can be obtained by the conventional post-processing technology, including but not limited to centrifugation, water washing, drying and the like.

Therefore, the method has the advantages that the pretreatment step is controlled, the solution to be crystallized (namely sugar water) is subjected to oxidation decolorization, the content of organic impurities in the primary sugar of acesulfame is reduced, and the defects of low product purity, yellow color and the like caused by the fact that the organic impurities are brought into a final crystallized product are avoided; in addition, the crystallization process and the process are controlled, so that a high-quality and high-purity crystallized product is obtained, the impurity content is low, and the purity and the quality of the acesulfame potassium crystal are obviously improved; and the method has the advantages of simple process, mild and controllable conditions, low technical requirements on equipment and personnel, and suitability for large-scale industrial production.

The amount of hydrogen peroxide

The amount of the hydrogen peroxide is not limited, and in some embodiments, the amount of the hydrogen peroxide is 0.1 wt% to 10 wt%, preferably 0.5 wt% to 2 wt%, of the total mass of the crude acesulfame potassium solution. The amount of the organic impurities in the crude acesulfame-K product solution can be predicted or estimated, so that the amount of the hydrogen peroxide can be determined according to the total mass of the crude acesulfame-K product solution, and if the amount of the hydrogen peroxide is less than 0.1 wt% of the total mass of the crude acesulfame-K product solution, the amount of the hydrogen peroxide is too small, so that the organic impurities with reducibility in the hydrogen peroxide cannot be completely neutralized; if the mass consumption of the hydrogen peroxide is more than 10 wt% of the total mass of the crude product solution of the acesulfame potassium, the consumption is excessive, and the excessive hydrogen peroxide has strong oxidizability, so that the equipment can be corroded by the excessive hydrogen peroxide, and the post-treatment process is complex and difficult to treat.

The amount of activated carbon

The amount of activated carbon is not limited herein, and in some embodiments, the amount of activated carbon is 0.1 wt% to 5 wt%, preferably 0.2 wt% to 4 wt%, based on the total mass of the crude solution of acesulfame k. The amount of the colored impurities in the crude acesulfame-K solution can be predicted or estimated, so the dosage of the activated carbon can be determined according to the total mass of the crude acesulfame-K solution, and if the dosage of the activated carbon is less than 0.1 wt% of the total mass of the crude acesulfame-K solution, the dosage is too small to completely adsorb the colored impurities in the crude acesulfame-K solution; if the mass consumption of the activated carbon is more than 5 wt% of the total mass of the crude acesulfame potassium solution, the consumption is too much, unnecessary waste is caused, and burden is also added to the subsequent filtering procedure.

Reaction conditions in the pretreatment step

In the pretreatment step, two reactions occur simultaneously, wherein one reaction is an oxidation-reduction chemical reaction of hydrogen peroxide and organic impurities, and the other reaction is a physical adsorption reaction of activated carbon on colored impurities, and the two reactions can achieve an ideal effect under certain conditions, and the first preset temperature is 40-90 ℃ in the step determined by a large amount of screening work; the first preset time is 1-8 h.

If the first preset temperature is lower than 40 ℃ and the first preset time is shorter than 1h, the redox chemical reaction and the physical adsorption reaction cannot react completely because the conditions are too mild and the contact time is too short; if the first preset temperature is higher than 90 ℃ and the first preset time is longer than 8 hours, the redox chemical reaction and the physical adsorption reaction are too violent due to too violent conditions, too long contact time and too violent reaction, especially the redox chemical reaction, and even local bumping can be caused.

Mode and conditions of concentration during nucleation

In the nucleation step, the concentration mode and conditions are not limited, in some embodiments, the concentration is performed by reduced pressure distillation, and the temperature of the reduced pressure distillation is 45-80 ℃, preferably 55-65 ℃; the pressure of the reduced pressure distillation is maintained between-95 KPa and-101 KPa, and the time of the reduced pressure distillation is 10min to 12 min. The reduced pressure distillation condition is based on quickly leading the acesulfame potassium mother liquor to reach the preset concentration, and does not generate excessive load on equipment.

Predetermined concentration during nucleation

In the nucleation step of the present application, the predetermined concentration is not limited, and in some embodiments of the present application, the predetermined concentration is such that the solid phase content is 30 wt% to 90 wt%, preferably 40 wt% to 80 wt% of the total mass of the acesulfame potassium mother liquor.

The setting of the preset concentration is related to whether subsequent crystal nuclei and crystals can be generated smoothly, and in the concentration process, if the solid phase content in the acesulfame potassium mother liquor is less than 30 wt% of the total mass of the acesulfame potassium mother liquor, the solvent is excessive, so that the crystal nuclei are difficult to generate in the subsequent crystal nucleus generation step; if the solid phase content in the acesulfame-K mother liquor is more than 90 wt% of the total mass of the acesulfame-K mother liquor, the solvent is too little, so that the solvent is quickly and completely evaporated in the heat preservation process of the subsequent crystal nucleus generation step, the crystal nucleus and the crystal can not be effectively separated, a large amount of irregular crystals are generated, and even the whole refining process fails.

Temperature and time conditions for nucleation

In the nucleation step of the present application, the second preset temperature is 40 to 70 ℃, preferably 45 to 60 ℃; the second preset time is 0.1-4 h; preferably 0.5h to 2 h.

In the process of forming crystal nucleus, the heat preservation temperature and the heat preservation time are important parameters for promoting the generation of the crystal nucleus, and if the heat preservation temperature and the heat preservation time are not properly controlled, the crystal nucleus cannot be generated. In some embodiments of the present application, the second predetermined temperature is 40 to 70 ℃, and the second predetermined time is 0.1 to 4 hours; in other embodiments of the present application, the predetermined temperature is 45 to 60 ℃; the second preset time is 0.5-2 h. If the second preset temperature is lower than 40 ℃, the temperature is too low, so that the solvent is slowly evaporated in the process of forming crystal nuclei, and the crystal nuclei are difficult to separate out; if the second preset temperature is higher than 60 ℃, the temperature is too high, so that the precipitated crystal nuclei are extremely irregular in the process of forming the crystal nuclei; the setting of the holding time also requires a great deal of investigation, and if the time, i.e. the second preset time is shorter than 0.1h, the time is too short, so that crystal nuclei are not separated out yet or just begin to be separated out or only a small amount of crystal nuclei are separated out, and the crystal nuclei are too few, so that effective crystal seeds cannot be provided for the subsequent crystallization step; if the time is as long as 2 hours, the time is too long, crystal nuclei are precipitated in a large amount, and even partial crystals are generated, and the crystal form is complex and is not the crystal form expected in the application.

Programmed temperature reduction condition in crystal formation process

In the crystal formation step of the present application, the selection of the temperature programmed condition is a key step directly related to whether a large amount of high quality crystals can be formed rapidly, and in some embodiments of the present application, the temperature programmed is: firstly, cooling to 40-45 ℃ from a second preset temperature at the speed of 1 ℃/10-60 min, and keeping for 0.5-8 h; then cooling to 8-12 ℃ at the speed of 1 ℃/10-60 min. In other embodiments of the present application, the temperature is first reduced from the second preset temperature to 45 ℃ at a rate of 1 ℃/10-60 min, and is kept for 0.5 h-8 h; then cooling to 10 ℃ at the speed of 1 ℃/10-60 min.

The method can be used for preparing the high-purity acesulfame potassium crystal, the purity of the prepared acesulfame potassium is higher than 99.30 percent, the content of organic impurities is lower than 10ppm, and the content of water is lower than 0.3wt percent.

At present, in the prior art, the purity of the acesulfame-K is generally 93.0 wt% -99.0% and is difficult to reach the purity of more than 99.0%, and the purity of the acesulfame-K prepared by the refining method is higher than 99.0%, the content of organic impurities is lower than 10ppm, and the content of water is lower than 0.3 wt%.

The acesulfame potassium crystals prepared in some embodiments of the present application are determined by XRD, and before drying, the positions of three strongest groups of diffraction peaks of the acesulfame potassium crystals are 8.8 +/-0.2, 17.3 +/-0.2 and 28.8 +/-0.2 respectively; after drying, the peak intensity of XRD of the acesulfame potassium crystal is weaker than that of the acesulfame potassium crystal before drying, and at this time, the position of the strongest peak is 8.8 + -0.2, and the position of the second strongest peak is 17.3 + -0.2. Therefore, the prepared wet acesulfame potassium sample has a good crystal structure, and the XRD spectrum peak of the sample is simple and has high strength; the obtained sample is dried to be an anhydrous sample, the partial crystal structure is destroyed, and the XRD spectrum peak of the sample is weaker than that before drying.

Test methods referred to in the present application

The test means adopted in each example and comparative example in the present application are described below, and are not described in detail in each example.

The analytical test method of acesulfame potassium (acesulfame potassium) in the beverage according to the national standard GB/T5009.140-2003 of food additives can be referred to in the application.

Assay and determination conditions for acesulfame K: japan Shimadzu high performance liquid chromatograph (ultraviolet detector), LC-10ADVP high pressure pump, CTO-10ASVP thermostated container; a chromatographic column: agilent XDB C18 column (250 mm. times.4.6 mm, 5 μm); mobile phase: 0.02mol/L ammonium sulfate (780mL) + methanol (100mL) + acetonitrile (30 mL); column temperature: 30 ℃; flow rate: 0.8 mL/min. The content is measured by an external standard method.

Method or condition for measuring impurity content (ignition residue): as above.

Measurement conditions of X-ray diffraction Pattern (XRD): x-ray diffractometer, model Bruker B8Advance, using K.alpha.1 radiation from a Cu target at a wavelength of 1.5418 nm.

Method and conditions for testing moisture content: refer to national standard GB/T6283-.

Example 1

Adding 0.5g of active carbon and 0.5g of hydrogen peroxide into 200mL (containing 20 wt% of acesulfame potassium) of acesulfame potassium solution to be crystallized obtained in the previous step, stirring and preserving heat at 80 ℃ for 2h, filtering the active carbon while the solution is hot, and carrying out reduced pressure distillation and concentration on the obtained sugar solution at-0.095 MPa and 70 ℃ for 1h to reach the preset concentration of 30 wt%. The concentrated solution was kept at 60 ℃ for 1 hour to form effective nuclei. Cooling to about 45 ℃ at the speed of 20 minutes per 1 ℃, and then preserving heat for 2 hours; then the temperature is reduced to about 10 ℃ at the speed of 20 minutes per 1 ℃, and a large amount of crystals are obtained. Centrifuging and washing with a small amount of cold ultrapure water to obtain a wet centrifuged sample, and drying to obtain 25g of high-purity solid crystals with purity of 99.5%, impurity content of 10ppm and water content of 0.2 wt%. The XRD spectra of the sample before and after drying are shown in figure 1.

Comparative example 1

200mL (containing 20 wt% of acesulfame potassium) of the acesulfame potassium solution to be crystallized obtained in the previous process is directly subjected to reduced pressure distillation and concentration for 1h at 70 ℃ under the pressure of-0.095 MPa, until the solid concentration of the acesulfame potassium is 30 wt%, thus obtaining an acesulfame potassium mother solution, then the acesulfame potassium mother solution is rapidly cooled to 10 ℃ and crystallized for 12h, thus obtaining a large amount of crystals. After centrifugation and washing with a small amount of cold ultrapure water, a wet centrifuged sample was obtained, and after drying, 21g of high-purity solid crystals having a purity of 99.0%, an impurity content of 50ppm and a water content of 0.3 wt% were obtained. The XRD spectra measured before and after drying the sample are shown in the data of figure 1.

As seen from example 1 and comparative example 1, 25g of acesulfame-K solid was obtained in example 1, and 21g of acesulfame-K solid was obtained in comparative example 1, i.e., the yield of acesulfame-K crystals in example 1 was much higher than that in comparative example 1.

Fig. 1 shows XRD patterns of the acesulfame potassium crystals prepared in example 1 and comparative example 1. Wherein, the XRD spectrums before the dry of the acesulfame potassium samples prepared in the example 1 and the comparative example 1 are respectively shown by the curve 1 and the curve 3, namely, the XRD spectrums of the wet samples, and the XRD spectrums after the dry of the acesulfame potassium samples prepared in the example 1 and the comparative example 1 are respectively shown by the curve 2 and the curve 4, namely, the XRD spectrums of the dry samples. It can be seen from fig. 1 that there is a great difference in the crystal structures obtained by the two methods of example 1 and comparative example 1:

first, as can be seen from the curve 3 in FIG. 1, the acesulfame potassium sample before drying prepared in comparative example 1 has almost no signal, indicating that the sample has a substantially amorphous structure, while as can be seen from the curve 1, the acesulfame potassium sample before drying prepared in example 1 has a large XRD spectrum peak intensity, a simple peak with a large intensity, and a very good crystal structure, and the diffraction peak positions of the corresponding strongest three groups are 8.8. + -. 0.2, 17.3. + -. 0.2 and 28.8. + -. 0.2, respectively, and a small peak at 34.5. + -. 0.2.

Secondly, as can be seen from the 2-curve and the 4-curve, the crystals of the anhydrous samples obtained by drying the samples obtained in the comparative example 1 and the example 1 have obvious changes, the dried acesulfame potassium sample prepared in the comparative example 1 forms a certain crystal structure after being dried, and the main peak position is almost consistent with the peak of the dried sample prepared by the method, which shows that the main crystal form is basically consistent. However, the peak of the dry acesulfame potassium prepared in comparative example 1 is weaker than that of the present method, which also indicates that the crystal structure of the final product of example 1 is better. Comparing the XRD spectrogram of the sample prepared in the application example 1 after drying, the spectral peaks before and after drying are obviously changed, the strongest diffraction peak position of the spectral peak of the dried sample is 8.8 +/-0.2, the second strongest peak position is 17.3 +/-0.2, a small peak is left at 28.8 +/-0.2, the small peak of 34.5 +/-0.2 disappears, and small peaks appear at 19.5 +/-0.2 and 28.6 +/-0.2, which shows that part of the crystal structure is destroyed in the drying process, the crystal integrity of the sample after drying the product is reduced, and crystal forms with other structures appear.

Example 2

Adding 0.5g of active carbon and 0.5g of hydrogen peroxide into 200mL (containing 20 wt% of acesulfame potassium) of acesulfame potassium solution to be crystallized obtained in the previous step, stirring and preserving heat at 80 ℃ for 2h, filtering the active carbon while hot, and distilling and concentrating the obtained sugar solution under reduced pressure (-0.095MP, 70 ℃) for 1h to reach the preset concentration of 40 wt%. The concentrated solution was kept at 60 ℃ for 1 hour to form effective nuclei. Cooling to about 45 ℃ at the speed of 10 minutes per 1 ℃, and then preserving heat for 1 hour; then the temperature is reduced to about 10 ℃ at the speed of 10 minutes per 1 ℃, and a large amount of crystals are obtained. Centrifuging and washing with a small amount of cold ultrapure water to obtain a wet centrifuged sample, and drying to obtain 31g of high-purity solid crystals with a purity of 99.2%, an impurity content of 20ppm and a water content of 0.3 wt%. The XRD spectra measured before and after drying the sample are shown in the data of figure 1.

Example 3

Adding 0.5g of active carbon and 0.5g of hydrogen peroxide into 200mL (containing 20 wt% of acesulfame potassium) of acesulfame potassium solution (namely sugar water) obtained in the previous step, stirring and preserving heat at 80 ℃ for 2h, filtering the active carbon while the solution is hot, and distilling and concentrating the sugar water under reduced pressure (-0.095MPa, 70 ℃) for 1h to reach the preset concentration of 45 wt%. The concentrated solution was kept at 50 ℃ for 1 hour to form effective nuclei. Cooling to about 40 ℃ at the speed of every 1 ℃ for 30 minutes, and then preserving heat for 2 hours; then the temperature is reduced to about 10 ℃ at the speed of every 1 ℃ for 30 minutes to obtain a large amount of crystals. Centrifuging and washing with a small amount of cold ultrapure water to obtain a wet centrifuged sample, and drying to obtain 32g of high-purity solid crystals with a purity of 99.6%, an impurity content of 4ppm and a water content of 0.2 wt%.

Example 4

Adding 0.5g of active carbon and 0.5g of hydrogen peroxide into 200mL (containing 25 wt% of acesulfame potassium) of acesulfame potassium solution (namely sugar water) obtained in the previous step, stirring and preserving heat at 70 ℃ for 2h, filtering the active carbon while hot, and distilling and concentrating the sugar water under reduced pressure (-0.095MPa, 70 ℃) for 1h to reach the preset concentration of 45 wt%. The concentrated solution was kept at 50 ℃ for 1 hour to form effective nuclei. Cooling to about 40 ℃ at the speed of every 1 ℃ for 30 minutes, and then preserving heat for 2 hours; then the temperature is reduced to about 10 ℃ at the speed of every 1 ℃ for 30 minutes to obtain a large amount of crystals. Centrifuging and washing with a small amount of cold ultrapure water to obtain a wet centrifuged sample, and drying to obtain 40g of high-purity solid crystals with a purity of 99.5%, an impurity content of 6ppm and a water content of 0.2 wt%.

Example 5

Adding 0.5g of active carbon and 0.5g of hydrogen peroxide into 200mL (containing 25 wt% of acesulfame potassium) of acesulfame potassium solution (namely sugar water) obtained in the previous step, stirring and preserving heat at 80 ℃ for 2h, filtering the active carbon while the solution is hot, and distilling and concentrating the sugar water under reduced pressure (-0.095MPa, 70 ℃) for 1h to reach the preset concentration of 45 wt%. The concentrated solution was kept at 50 ℃ for 1 hour to form effective nuclei. Cooling to about 40 ℃ at the speed of every 1 ℃ for 30 minutes, and then preserving heat for 2 hours; then the temperature is reduced to about 10 ℃ at the speed of every 1 ℃ for 30 minutes to obtain a large amount of crystals. Centrifuging and washing with a small amount of cold ultrapure water to obtain a wet centrifuged sample, and drying to obtain 42g of high-purity solid crystals with a purity of 99.2%, an impurity content of 15ppm and a water content of 0.2 wt%.

Comparative example 2

200mL (containing 25 wt% of acesulfame potassium) of the acesulfame potassium solution to be crystallized obtained in the previous step is heated and distilled, 0.5g of active carbon is added, and the active carbon is filtered out when the solution is hot after stirring and heat preservation at 70 ℃ for 2 h. The treated sugar solution is subjected to distillation and concentration for 1h under reduced pressure (-0.095MPa, 70 ℃) until the preset concentration is 40 wt%. The concentrated solution was kept at 55 ℃ for 1 hour to form effective nuclei. Cooling to about 45 ℃ at the speed of 10 minutes per 1 ℃, and then preserving heat for 1 hour; then the temperature is reduced to about 10 ℃ at the speed of 10 minutes per 1 ℃, and a large amount of crystals are obtained. Centrifuging and washing with a small amount of cold ultrapure water to obtain a wet centrifuged sample, drying to obtain 38g of high-purity solid crystals with a purity of 99.2%, an impurity content of 35ppm and a water content of 0.3 wt%.

Comparative example 3

200mL (containing 25 wt% of acesulfame potassium) of acesulfame potassium solution to be crystallized obtained in the previous step is heated and distilled, 0.5g of hydrogen peroxide is added, and after stirring and heat preservation are carried out at 80 ℃ for 2h, reduced pressure (-0.095MPa, 70 ℃) is carried out for distillation and concentration for 1h, until the preset concentration is 40 wt%. The concentrated solution was kept at 60 ℃ for 1 hour to form effective nuclei. Cooling to about 45 ℃ at the speed of 10 minutes per 1 ℃, and then preserving heat for 1 hour; then the temperature is reduced to about 10 ℃ at the speed of 10 minutes per 1 ℃, and a large amount of crystals are obtained. Centrifuging and washing with a small amount of cold ultrapure water to obtain a wet centrifuged sample, drying to obtain 37g of high-purity solid crystals with a purity of 99.2%, an impurity content of 25ppm and a water content of 0.3 wt%.

In order to more intuitively compare the technical effects of the examples and the comparative examples, the product performances and the yield of the obtained products of the examples 1 to 5 and the comparative examples 1 to 3 are listed in table 1, wherein the solid content of the acesulfame potassium in the solution to be crystallized is obtained by multiplying the volume of the solution to be crystallized of the acesulfame potassium by the corresponding mass fraction.

Table 1: the product performance and yield obtained in examples 1 to 5 and comparative examples 1 to 3

The comparative examples 2 and 3 adopt a single mode to pretreat the acesulfame potassium solution to be crystallized, and the results of the examples 5, 2 and 3 show that the impurity content of the final product is higher than that of the final product which adopts hydrogen peroxide and active carbon to pretreat the acesulfame potassium solution to be crystallized simultaneously; as can be seen from example 2, comparative example 2 and comparative example 3, the yield of the acesulfame potassium crystals in example 2 is significantly higher than in comparative example 2 and comparative example 3, indicating that the yield of the final product obtained by pretreating the solution to be crystallized of acesulfame potassium with hydrogen peroxide and activated carbon simultaneously is higher than the yield of the final product obtained by pretreating the solution to be crystallized of acesulfame potassium in a single manner. In addition, the refining effects of example 1 and comparative example 1 are significantly inferior to those of examples 2 to 5, because both example 1 and comparative example 1 concentrate the acesulfame potassium mother liquor to a preset concentration of 30 wt%, and the refining effect is inferior to that of the acesulfame potassium mother liquor to a preset concentration of 40 wt% or 45 wt%.

In summary, the method has the advantages that the pretreatment step is controlled, the solution to be crystallized (namely sugar water) is subjected to oxidation decolorization, so that the content of organic impurities in the primary sugar of acesulfame is reduced, and the defects of low purity, yellow color and the like caused by the fact that the organic impurities are brought into a final crystallized product are avoided; in addition, the crystallization process and the process are controlled, so that a high-quality and high-purity crystallized product is obtained, the impurity content is low, and the purity and the quality of the acesulfame potassium crystal are obviously improved; and the method has the advantages of simple process, mild and controllable conditions, low technical requirements on equipment and personnel, and suitability for large-scale industrial production.

While the foregoing is directed to embodiments of the present application, other modifications and variations of the present application may be devised by those skilled in the art in light of the above teachings. It should be understood by those skilled in the art that the foregoing detailed description is for the purpose of better explaining the present application, and the scope of protection of the present application shall be subject to the scope of protection of the claims.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.