Acesulfame potassium hydrolysis process and application

Abstract

The invention belongs to the technical field of food additive preparation, and particularly relates to an acesulfame potassium hydrolysis process and application. The process adopts a secondary hydrolysis process, and comprises the following steps: introducing sulfonation liquid in a front section and washing acid water (2-4%) in a rear section into a first hydrolysis reactor, and accurately controlling the specific gravity of hydrolysis acid and temperature parameters (for example, the specific gravity is 1.2-1.3, and the temperature is-5 DEG C to 15 DEG C); materials in the middle of the first hydrolysis reactor continuously overflow into a second hydrolysis reactor (hydrolysis transfer kettle) containing a stirring pump and an external circulation pump, the reaction time is prolonged, mass transfer is enhanced through external circulation, and the material retention time is prolonged; and feeding the material in the second hydrolysis reactor into a hydrolysis layering tank, standing, separating an upper-layer acid phase, washing a lower-layer organic phase with water, and finally neutralizing with potassium hydroxide to obtain an acesulfame potassium crude product sugar water solution. The reaction sufficiency is improved through secondary hydrolysis, the temperature is stabilized, the ice maker load and the labor intensity are reduced, the process adaptability is enhanced, and the acesulfame potassium production stability and yield are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of food additive preparation technology, specifically relating to an acesulfame potassium hydrolysis process and its application. Background Technology

[0002] Acesulfame potassium (acesulfame K), as a low-calorie, high-sweetness artificial sweetener, is widely used in food, beverages, health products and other fields. The maturity and stability of its production process are directly related to product quality, production cost and industrial mass production efficiency. In the conventional production process of acesulfame potassium, several key reactions are involved: First, aminosulfonic acid reacts with amine compounds (such as triethylamine) in a dichloromethane solvent system to generate an ammonium aminosulfonate solution; then, this solution reacts further with diketene to obtain an acesulfame-triethylamine salt solution; subsequently, the acesulfame-triethylamine salt needs to be converted into a cyclic intermediate through a cyclization reaction. This reaction is usually carried out in an inorganic or organic solvent using sulfur trioxide as the cyclizing agent, ultimately generating a cyclic sulfur trioxide adduct; the hydrolysis stage, as the core link between the cyclization and neutralization reactions, needs to convert the cyclic sulfur trioxide adduct into acesulfame acid, providing a key raw material for the subsequent neutralization with potassium hydroxide to produce acesulfame potassium. Therefore, the efficiency and control precision of the hydrolysis reaction are crucial to the entire production process.

[0003] Traditional acesulfame potassium hydrolysis processes employ a "single-stage hydrolysis" reaction system. The specific operation process is as follows: the cyclic sulfur trioxide adduct material obtained from the cyclization reaction in the previous stage is directly fed into a single hydrolysis reactor. The hydrolysis reaction is initiated by adding water washing acid from the subsequent stage to the hydrolysis reactor. During the reaction, the specific gravity of sulfuric acid in the system must be strictly controlled. After the reaction is completed, all the material in the hydrolysis reactor is transferred to a hydrolysis layering reactor. The hydrolyzed organic phase and acid phase are obtained by static separation. The hydrolyzed organic phase is used for the subsequent water washing process, while the acid phase is supplied to the extraction process. However, this traditional process has revealed many defects and shortcomings in actual industrial applications: First, the hydrolysis reaction is concentrated in a single hydrolysis vessel, and the reaction process is violent and exothermic, making it difficult to control the temperature inside the hydrolysis vessel stably. Temperature fluctuations not only easily trigger side reactions such as acesulfame K decomposition and carbonization of sulfuric acid and organic impurities, but also disrupt the phase equilibrium of the subsequent water washing process, resulting in a "disordered phase" phenomenon. This makes it difficult to separate the hydrolyzed organic phase from the aqueous phase, directly reducing the recovery rate of the target product. Second, the discharge time after the hydrolysis vessel completes the reaction is relatively long, and the dripping rate and amount of the washing acid are extremely sensitive to the reaction results. Excessive dripping will lead to an excessively low sulfuric acid concentration, reducing the hydrolysis reaction rate and the conversion rate of cyclic adducts. Insufficient dripping will cause the sulfuric acid specific gravity to exceed the control range, interfering with the reaction. Both hydrolysis stratification and hydrolysis can lead to a reduction in the amount of organic phase generated during hydrolysis, ultimately resulting in a decrease in product yield. Thirdly, to suppress the intense exothermic reaction during primary hydrolysis, a high-intensity cooling system is required, causing the shallow and deep cooling loads of the ice machine to remain high for extended periods. This not only increases refrigeration energy consumption but also makes it prone to untimely cooling due to excessive ice machine load, further exacerbating temperature fluctuations in the hydrolysis reactor. At the same time, operations such as temperature monitoring, material discharge adjustment, and acid water droplet addition control require frequent manual intervention, which increases the labor intensity of workers and is prone to production abnormalities due to human error. These problems make it difficult for traditional hydrolysis processes to meet the requirements of high efficiency, stability, and low energy consumption in the industrial production of acesulfame potassium. Therefore, optimizing and improving the hydrolysis process has urgent practical significance and technical necessity. Summary of the Invention

[0004] To address the aforementioned shortcomings, this invention provides a hydrolysis process for the production of acesulfame potassium. This process achieves secondary hydrolysis by adding a hydrolysis transfer vessel after the hydrolysis reactor: extending the reaction time to fully convert the raw materials and significantly improving product yield; dispersing the exothermic reaction, stabilizing the hydrolysis temperature, reducing side reactions, and lowering refrigeration energy consumption; the transfer vessel acts as a buffer, reducing production fluctuations and lowering manual labor intensity; simultaneously, it broadens the adjustment range of the hydrolysis acid specific gravity, improves the process's tolerance to parameter fluctuations, enhances production adaptability and risk resistance, and makes it easier to adapt to different operating conditions.

[0005] The technical solution of this invention is as follows: On the one hand, the present invention provides an acesulfame potassium hydrolysis process, including the following steps: (1) The sulfonation liquid from the previous stage and the washing acid water from the subsequent stage are fed into the first hydrolysis reactor. The specific gravity of the hydrolysis acid in the reactor can be controlled to be 1.2-1.3 and the temperature can be -5℃-15℃. (2) The material in the middle of the first hydrolysis reactor continuously overflows into the second hydrolysis reactor, which is equipped with a stirring device and an external circulation pump. The external circulation pump is used to enhance mass transfer. (3) The material in the second hydrolysis reactor is fed into the hydrolysis stratification tank for static separation to obtain an upper acid phase and a lower organic phase; (4) The lower organic phase is washed with water and then neutralized with potassium hydroxide to obtain crude acesulfame potassium aqueous solution.

[0006] Specifically, the concentration of the acidic water used for washing in step (1) can be 2% m / m, 3% m / m or 4% m / m.

[0007] Specifically, in step (1), the specific gravity of the hydrolytic acid in the first hydrolysis reactor can be 1.2, 1.25 or 1.3.

[0008] Specifically, the concentration of the acid water used for washing in step (1) can be 2% m / m, and the specific gravity of the hydrolytic acid in the first hydrolysis reactor in step (1) can be 1.2.

[0009] Specifically, the acidic water used in step (1) is a byproduct of the water washing and extraction step in the production of acesulfame potassium, which can be recycled and reintroduced into the first hydrolysis reactor.

[0010] Specifically, the sulfonation liquid in step (1) contains acesulfame potassium trioxide adduct, which is generated by the reaction of acetoacetyl-N-sulfonate with sulfur trioxide at low temperature.

[0011] Specifically, the content of the acetoacetyl-N-sulfonate is ≥38%m / m.

[0012] Specifically, the concentration of potassium hydroxide in step (4) can be 10%-16%m / m.

[0013] On the other hand, the present invention provides the application of the aforementioned acesulfame hydrolysis process in acesulfame production.

[0014] The beneficial effects of this invention are as follows: (1) A two-stage hydrolysis mode is adopted, and a hydrolysis transfer vessel is added after the hydrolysis reactor to extend the reaction time of the sulfonation liquid and the washing acid water, so as to promote the more complete conversion of the cyclic sulfur trioxide adduct into acesulfame acid and reduce the loss of the target product. Compared with the traditional one-stage hydrolysis process, the product yield is significantly improved.

[0015] (2) Secondary hydrolysis disperses the exothermic reaction process, avoiding the drastic temperature fluctuations caused by concentrated heat release in traditional primary hydrolysis, keeping the temperature of the hydrolysis process in a stable range, effectively reducing side reactions caused by abnormal temperature; at the same time, the gentle heat release rate reduces the cooling load of the ice machine, reduces refrigeration energy consumption, and alleviates the pressure on equipment operation.

[0016] (3) The hydrolysis transfer kettle can play a buffer and regulation role. Even if the sulfonation discharge speed is too fast or the ice machine load is too large, it can avoid the problems of abnormal discharge of the hydrolysis kettle and the low proportion of neutralized sugar water, thus reducing production fluctuations. The temperature is stable and the discharge is smooth, so there is no need for frequent manual monitoring and adjustment of parameters, which greatly reduces the labor intensity of workers.

[0017] (4) Compared with the strict requirements of traditional processes on parameters, this process can maintain stable production within a wider range of adjustment of the specific gravity of hydrolyzed acid, has a higher tolerance for fluctuations in operating parameters, improves the stability and risk resistance of industrial production, and is more easily adapted to different production conditions. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0019] The present invention will be further clearly and completely illustrated below through embodiments. These embodiments are only some examples of the present invention and are not intended to limit the present invention, but are only for illustrating the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are all conventional experiments, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0020] Example 1 The sulfonation solution (the intermediate acetoacetyl-N-sulfonate content in the synthesis section is ≥38% m / m) and the sulfonating agent sulfur trioxide are reacted under low temperature conditions. After the aromatic hydrocarbon is sulfonated, the sulfonic acid group is replaced by the amino group to generate acesulfame trioxide adduct. A 2% concentration (mainly water, the effective functional component is sulfuric acid, a very low concentration sulfuric acid solution with mild properties; that is, every 100g of this acidic water contains 2g~3g of pure sulfuric acid, with the remaining 97g~98g of water) is used as a byproduct of the "water washing extraction" step in acesulfame production: when the organic phase (containing acesulfame intermediate) is washed with water, a small amount of sulfuric acid dissolves into the water, forming this low-concentration acidic water, which can be recycled and fed back into the first hydrolysis reactor to achieve acid recycling and reduce raw material consumption.) enters the first hydrolysis reactor. The middle of the hydrolysis reactor continuously discharges the material into the second hydrolysis reactor. (The hydrolyzed material passes through...) The hydrolysis circulating pump is controlled at -5℃ to 15℃ via a heat exchanger to prevent the hydrolysis reactor temperature from becoming too high and causing the formation of byproducts. Additionally, the large amount of pressure released during the hydrolysis reaction is vented through a vent pipe connected to the hydrolysis reactor, maintaining the reactor at a slightly positive pressure. The hydrolysis reactor continuously discharges into a hydrolysis stratification tank, while the lower organic phase is continuously separated into an organic phase tank, and the upper acid (sulfuric acid) phase is continuously separated into an acid phase tank. The specific gravity of the hydrolysis acid is controlled at 1.2 (concentration at 30%). After separation, the organic phase is neutralized with potassium hydroxide solution (content at 10-16% m / m) in a neutralization tubular reactor. (The neutralization tubular mixing reactor receives the washed organic phase, prepared alkali solution, and neutralized wash water at a certain flow rate; the pH is controlled at 9.0-11.5, and the specific gravity of the sugar solution is controlled at above 1.07 g / mL.) Sugar solution is obtained, and the yield of acesulfame potassium is analyzed to be 99.1%.

[0021] Example 2 The sulfonated liquid and a 3% concentration of acidic water were fed into the first hydrolysis reactor. The middle of the hydrolysis reactor was continuously discharged into the second hydrolysis reactor, and the second hydrolysis reactor was continuously discharged into the hydrolysis stratification tank. At the same time, the lower organic phase was continuously separated into the organic phase tank, and the upper acid phase was continuously separated into the acid phase tank. The specific gravity of the hydrolysis acid was controlled at 1.25 (concentration 31%). After the organic and acid phases were washed and extracted with water, they were neutralized with potassium hydroxide to obtain sugar water. The yield of acesulfame potassium was 99.0%.

[0022] Example 3 The sulfonated liquid and 4% water-washed acid solution were fed into the first hydrolysis reactor. The middle of the hydrolysis reactor was continuously discharged into the second hydrolysis reactor, and the second hydrolysis reactor was continuously discharged into the hydrolysis stratification tank. At the same time, the lower organic phase was continuously separated into the organic phase tank, and the upper acid phase was continuously separated into the acid phase tank. The specific gravity of the hydrolysis acid was controlled at 1.3 (concentration 47%). After the organic phase and acid phase were washed and extracted with water, they were neutralized with potassium hydroxide to obtain sugar water. The yield of acesulfame potassium was 98.1%.

[0023] The other conditions for Examples 2 and 3 are the same as those for Example 1. The yield is described below (including details of yield detection). Following the above method, the checkerboard method was used for the experiment. Specifically, the reaction was continued with 2% m / m acid water, and two sets of Examples 4 and 5 were conducted, controlling the specific gravity of the hydrolysate acid at 1.25 and 1.3, respectively. Similarly, the reaction was carried out with 3% m / m acid water, and two sets of Examples 6 and 7 were conducted, controlling the specific gravity of the hydrolysate acid at 1.2 and 1.3, respectively. Likewise, the reaction was carried out with 4% m / m acid water, and two sets of Examples 8 and 9 were conducted, controlling the specific gravity of the hydrolysate acid at 1.2 and 1.25, respectively.

[0024] The yields were calculated above, and the results are shown in Table 1: Table 1

[0025] The highest yield was achieved in Example 1, which involved reacting the sulfonated solution with a 2% concentration of water-washing acid and controlling the hydrolytic acid ratio at 1.2, resulting in a yield of 99.5%.

[0026] I. Clearly defined yield in the process The “yield” mentioned in this process refers specifically to the molar yield of the target product, potassium acesulfame (acesulfame potassium, chemical formula C4H5NO4S·K). The calculation basis is the core raw material in the feed of the hydrolysis section—acesulfame sulfur trioxide adduct (acesulfame potassium cyclization intermediate), that is, the actual conversion efficiency of this intermediate into potassium acesulfame potassium through hydrolysis and neutralization reaction.

[0027] II. Yield Calculation Formula 1. Core Parameter Definition n1 (theoretical molar mass): Calculated based on the actual mass and molar mass of the acesulfame potassium trioxide adduct in the feed, the molar mass of the adduct is 241 g / mol (calculated according to the molecular formula C4H4NO5S).

[0028] n2 (actual molar mass): The molar mass of potassium acesulfame potassium was calculated to be 201 g / mol by detecting the actual mass and molar mass of potassium acesulfame potassium in the neutralized "sugar water".

[0029] 2. Calculation formula Molar yield of acesulfame potassium =

[0030] Where m1 is the mass (in g) of acesulfame potassium trioxide adduct in the feed of the first hydrolysis reactor, which is calculated by multiplying the feed volume by the feed concentration (high performance liquid chromatography HPLC detection value); m2 is the mass (in g) of acesulfame potassium in the neutralized "sugar water", calculated by multiplying the volume of the "sugar water" by the concentration of acesulfame potassium (HPLC detection value).

Claims

1. A hydrolysis process for acesulfame potassium, characterized in that, Includes the following steps: (1) The sulfonation liquid from the previous stage and the acid water from the subsequent stage are fed into the first hydrolysis reactor, and the specific gravity of the hydrolysis acid in the reactor is controlled to be 1.2-1.3 and the temperature is -5℃-15℃; (2) The material in the middle of the first hydrolysis reactor continuously overflows into the second hydrolysis reactor, which is equipped with a stirring device and an external circulation pump. The external circulation pump is used to enhance mass transfer. (3) The material in the second hydrolysis reactor is fed into the hydrolysis stratification tank for static separation to obtain an upper acid phase and a lower organic phase; (4) The lower organic phase is washed with water and then neutralized with potassium hydroxide to obtain crude acesulfame potassium aqueous solution.

2. The acesulfame potassium hydrolysis process according to claim 1, characterized in that, The concentration of the acidic water used for washing in step (1) is 2% m / m, 3% m / m, or 4% m / m.

3. The acesulfame potassium hydrolysis process according to claim 2, characterized in that, In step (1), the specific gravity of the hydrolytic acid in the first hydrolysis reactor is 1.2, 1.25 or 1.

3.

4. The acesulfame potassium hydrolysis process according to claim 2, characterized in that, The concentration of the acidic water used for washing in step (1) is 2% m / m.

5. The acesulfame potassium hydrolysis process according to claim 4, characterized in that, In step (1), the specific gravity of the hydrolytic acid in the first hydrolysis reactor is 1.

2.

6. The acesulfame potassium hydrolysis process according to claim 1, characterized in that, The acidic water used in step (1) is a byproduct of the water washing and extraction step in the production of acesulfame potassium. After being recovered, it can be fed back into the first hydrolysis reactor.

7. The acesulfame potassium hydrolysis process according to claim 1, characterized in that, The sulfonation solution described in step (1) contains acesulfame potassium trioxide adduct, which is generated by the reaction of acetoacetyl-N-sulfonate with sulfur trioxide at low temperature.

8. The acesulfame potassium hydrolysis process according to claim 7, characterized in that, The content of the acetoacetyl-N-sulfonate is ≥38%m / m.

9. The acesulfame potassium hydrolysis process according to claim 1, characterized in that, The concentration of potassium hydroxide in step (4) is 10%-16%m / m.

10. The application of the acesulfame hydrolysis process according to any one of claims 1-9 in the production of acesulfame.

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