Step-by-step neutralization reaction method in acesulfame potassium production process

Abstract

The invention provides a step-by-step neutralization reaction method in an acesulfame potassium production process, and belongs to the technical field of organic synthesis. According to the invention, step-by-step neutralization is adopted to replace primary neutralization, meanwhile, forced circulation of the tubular mixer is utilized to replace a tank reactor, and the purposes of reducing impurity precipitation in the acesulfame potassium aqueous solution and improving the product quality are achieved through step-by-step continuous reaction of potassium hydroxide aqueous solutions with different concentrations in different mixers; meanwhile, three times of reaction and separation are sequentially carried out, so that acesulfamic acid in an organic phase fully reacts with potassium hydroxide to the maximum extent and is separated out, and the product yield is improved; and meanwhile, continuous production operation is realized, the labor intensity of workers is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a step-by-step neutralization reaction method in the production process of acesulfame potassium. Background Art

[0002] Acesulfame potassium, whose chemical name is acesulfame potassium, has the advantages of being safe and non-toxic, stable in nature, refreshingly sweet, without any bad aftertaste, and reasonably priced. It is one of the most stable sweeteners in the world and is used as a sweetener in food, medicine, and other aspects.

[0003] Typically in conventional acesulfame potassium production methods, sulfamic acid is reacted with an amine (e.g., triethylamine) in a dichloromethane solvent to form an ammonium sulfamic acid salt solution. The ammonium sulfamic acid salt solution is then reacted with diketene to form an acetoacetyl triethylamine salt solution. The acetoacetyl triethylamine salt is cyclized, hydrolyzed, and neutralized to form acetoacetyl potassium.

[0004] Typically, acetoacesulfame triethylamine salt is intermediately cyclized to form a cyclic sulfur trioxide adduct by reacting with sulfur trioxide in an inorganic or organic solvent, the solvent used for the reaction being an organic solvent. The adduct formed by the reaction is subsequently hydrolyzed and then neutralized with potassium hydroxide to form acesulfame potassium.

[0005] The conventional reaction system of the neutralization section of potassium acesulfame is: the washed organic phase obtained in the previous section is pumped into the neutralization kettle, alkali solution is added dropwise, the pH value is adjusted to 10.5-11 once, and after standing and precipitation, the potassium acesulfame aqueous solution is separated. Because it is a one-time neutralization, the disadvantages are: the temperature of the reactor changes greatly, resulting in a large load on the ice machine; the residence time is long, the utilization rate of the device is low, and the production cost is high; and the one-step neutralization is used, the alkalinity of the neutralization solution is too strong, resulting in a high impurity content in the finished potassium acesulfame, and the product quality is not high.

[0006] Therefore, it is necessary to develop a step-by-step neutralization reaction method to replace the existing method, so as to reduce the precipitation of impurities in the acesulfame potassium aqueous solution and improve the product quality by reacting alkaline solutions of different concentrations in different mixers in a step-by-step manner, so as to fully react and separate the acesulfame acid and potassium hydroxide in the organic phase to the maximum extent, thereby improving the product yield; at the same time, the continuous production operation is realized, the labor intensity of workers is reduced, and the production efficiency is improved. Summary of the invention

[0007] Based on the deficiencies in the prior art, the present invention aims to provide a reaction method for step-by-step neutralization in the production process of acesulfame potassium, wherein the method adopts step-by-step neutralization instead of one-time neutralization, and utilizes a tubular mixer for forced circulation instead of a kettle reactor, and achieves the purpose of reducing the precipitation of impurities in the acesulfame potassium aqueous solution and improving the product quality by reacting potassium hydroxide aqueous solutions of different concentrations in different mixers in a step-by-step manner; at the same time, after three reactions and separations in sequence, the acesulfame acid in the organic phase is fully reacted with potassium hydroxide and separated to the maximum extent, thereby improving the product yield; at the same time, the continuous production operation is realized, the labor intensity of workers is reduced, and the production efficiency is improved.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The step-by-step neutralization reaction method in the production process of acesulfame potassium comprises the following steps:

[0010] (1) The water-washed organic phase obtained in the previous process and the alkali solution in the alkali solution tank are simultaneously and continuously pumped into the neutralization tubular reactor, and the water-washed organic phase and the alkali solution are converted into organic phase 1 through the neutralization tubular reactor; the organic phase 1 enters the neutralization tubular mixer, and the organic phase 1 is converted into organic phase 2 through the neutralization tubular mixer; the organic phase 2 enters the neutralization water washing tower, and the organic phase 2 is converted into organic phase 3 through the neutralization water washing tower; the organic phase 3 enters the extractant tank for extraction or is pumped to the subsequent stage for pre-steaming;

[0011] (2) the alkali solution 1 in the alkali water tank is continuously pumped into a neutralization water washing tower and mixed with the organic phase 2 in step (1), and then separated to obtain an organic phase 3 and alkali water 2; the alkali water 2 is continuously pumped into a neutralization tubular mixer and mixed with the organic phase 1 in step (1), and then separated to obtain an organic phase 2 and alkali water 3; the alkali water 3 is continuously fed into a neutralization tubular reactor and mixed with the water washing organic phase and the alkali solution, and then separated to obtain an organic phase 1 and an acesulfame potassium aqueous solution, and the acesulfame potassium aqueous solution is fed into a sugar water tank for subsequent steps;

[0012] Wherein, the alkali solution is a potassium hydroxide aqueous solution with a concentration of 10-15%;

[0013] The preparation method of the alkali solution is: mixing a potassium hydroxide solution with a concentration of 30%-50% with water to prepare an alkali solution with a concentration of 10%-15%;

[0014] Preferably, the concentration of the potassium hydroxide solution is 48%;

[0015] Preferably, the concentration of the alkali solution is 12-14%, more preferably 12%, 13% or 14%.

[0016] The alkaline water 1 is a potassium hydroxide aqueous solution with a concentration of 2-5%; preferably, the concentration of the alkaline water 1 is 2-4%, more preferably 2%, 3% or 4%;

[0017] The pH of the alkaline water 2 is 12-13, preferably, the pH of the alkaline water 2 is 12, 12.5 or 13;

[0018] The pH of the alkaline water 3 is 11-12, preferably, the pH of the alkaline water 2 is 11, 11.5 or 12;

[0019] The pH of the acesulfame potassium aqueous solution is 8.5-11, preferably, the pH of the acesulfame potassium aqueous solution is 9.0, 9.5 or 10;

[0020] The specific gravity of the acesulfame potassium aqueous solution is greater than or equal to 1.07 g / ml. Preferably, the specific gravity of the acesulfame potassium aqueous solution is 1.080 g / ml, 1.090 g / ml or 1.095 g / ml.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The conventional method is one-step neutralization. The washed organic phase obtained in the previous process is pumped into a neutralization kettle, and alkali solution is added dropwise. The pH value is adjusted to 10.511 once. After standing and settling, the potassium acesulfame aqueous solution is separated. Because the neutralization solution is too alkaline, the impurity content in the finished potassium acesulfame is high and the product quality is not high. The present invention adopts a step-by-step neutralization method and gradually reduces the concentration of the neutralizing alkali to reduce the precipitation of impurities in the washed dichloromethane solution, thereby improving the product quality, and the content is stabilized at more than 99.5%. At the same time, after three reactions and separations in sequence, the acesulfame acid in the organic phase is fully reacted with potassium hydroxide and separated to the maximum extent, thereby improving the product yield. The yield of the neutralization step is stabilized at more than 99%;

[0023] 2. The conventional method requires cooling the neutralization kettle, and the temperature of the reactor changes greatly, resulting in a large load on the ice machine; at the same time, because it is intermittent production, the residence time is long, the device utilization rate is low, and the production cost is high. The present invention adopts a method of forced circulation of a tubular reactor, so that the reaction can be carried out continuously, improve the level of automation, reduce the labor intensity of workers, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0025] Figure 1 The present invention is a flow chart of the neutralization section in the production process of acesulfame potassium. DETAILED DESCRIPTION

[0026] The following non-limiting examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. The following content is merely an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, which should also fall within the scope of the present invention.

[0027] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those generally understood by those of ordinary skill in the art to which the present invention belongs.

[0028] Example 1: Reaction method for stepwise neutralization in the production process of acesulfame potassium

[0029] The steps include:

[0030] (1) mixing a 48% potassium hydroxide solution with water to prepare a 12% alkali solution and a 2% alkali water 1;

[0031] (2) The washed organic phase and the alkali solution are continuously pumped into the neutralization tubular reactor at the same time, and the washed organic phase and the alkali solution are converted into organic phase 1 through the neutralization tubular reactor; the organic phase 1 enters the neutralization tubular mixer, and the organic phase 1 is converted into organic phase 2 through the neutralization tubular mixer; the organic phase 2 enters the neutralization water washing tower, and the organic phase 2 is converted into organic phase 3 through the neutralization water washing tower; the organic phase 3 enters the extractant tank for extraction or is pumped to the subsequent stage for pre-steaming;

[0032] (3) the alkali solution 1 in the alkali water tank is continuously pumped into a neutralization washing tower and mixed with the organic phase 2 in step (1), and then separated to obtain an organic phase 3 and alkali water 2; the alkali water 2 (the pH value of the alkali water 2 is controlled to be 12) is continuously pumped into a neutralization tubular mixer and mixed with the organic phase 1 in step (1), and then separated to obtain an organic phase 2 and alkali water 3; the alkali water 3 (the pH value of the alkali water 3 is controlled to be 11) is continuously introduced into a neutralization tubular reactor and washed with water to obtain an organic phase and alkali solution, and then separated to obtain an organic phase 1 and acesulfame potassium aqueous solution, i.e., sugar water, wherein the pH value of the sugar water is controlled to be 9.0, and the specific gravity of the sugar water is controlled to be 1.080 g / ml. The acesulfame potassium aqueous solution enters the sugar water tank for subsequent steps. After the sugar water solution is treated, the acesulfame potassium content in the finished product is 99.6%, and the yield of the neutralization step is 99.2%.

[0033] Example 2 Reaction method for stepwise neutralization in the production process of acesulfame potassium

[0034] The steps include:

[0035] (1) mixing a potassium hydroxide solution having a concentration of 48% with water to prepare an alkali solution having a concentration of 13% and an alkali water having a concentration of 3%;

[0036] (2) The washed organic phase and the alkali solution are continuously pumped into the neutralization tubular reactor at the same time, and the washed organic phase and the alkali solution are converted into organic phase 1 through the neutralization tubular reactor; the organic phase 1 enters the neutralization tubular mixer, and the organic phase 1 is converted into organic phase 2 through the neutralization tubular mixer; the organic phase 2 enters the neutralization water washing tower, and the organic phase 2 is converted into organic phase 3 through the neutralization water washing tower; the organic phase 3 enters the extractant tank for extraction or is pumped to the subsequent stage for pre-steaming;

[0037] (3) the alkali solution 1 in the alkali water tank is continuously pumped into a neutralization washing tower and mixed with the organic phase 2 in step (1), and then separated to obtain an organic phase 3 and alkali water 2; the alkali water 2 (the pH value of the alkali water 2 is controlled to be 12.5) is continuously pumped into a neutralization tubular mixer and mixed with the organic phase 1 in step (1), and then separated to obtain an organic phase 2 and alkali water 3; the alkali water 3 (the pH value of the alkali water 3 is controlled to be 11.5) is continuously introduced into a neutralization tubular reactor and washed with water to obtain an organic phase and alkali solution, and then separated to obtain an organic phase 1 and an acesulfame potassium aqueous solution, i.e., sugar water, wherein the pH value of the sugar water is controlled to be 9.5, and the specific gravity of the sugar water is controlled to be 1.090 g / ml. The acesulfame potassium aqueous solution enters the sugar water tank for subsequent steps. After the sugar aqueous solution is treated, the acesulfame potassium content in the finished product is 99.7%, and the yield of the neutralization step is 99.5%.

[0038] Example 3: Reaction method for stepwise neutralization in the production process of acesulfame potassium

[0039] The steps include:

[0040] (1) mixing a potassium hydroxide solution having a concentration of 48% with water to prepare an alkali solution having a concentration of 14% and an alkali water solution having a concentration of 4%;

[0041] (2) The washed organic phase and the alkali solution are continuously pumped into the neutralization tubular reactor at the same time, and the washed organic phase and the alkali solution are converted into organic phase 1 through the neutralization tubular reactor; the organic phase 1 enters the neutralization tubular mixer, and the organic phase 1 is converted into organic phase 2 through the neutralization tubular mixer; the organic phase 2 enters the neutralization water washing tower, and the organic phase 2 is converted into organic phase 3 through the neutralization water washing tower; the organic phase 3 enters the extractant tank for extraction or is pumped to the subsequent stage for pre-steaming;

[0042] (3) the alkali solution 1 in the alkali water tank is continuously pumped into a neutralization washing tower and mixed with the organic phase 2 in step (1), and then separated to obtain an organic phase 3 and alkali water 2; the alkali water 2 (the pH value of the alkali water 2 is controlled to be 13) is continuously pumped into a neutralization tubular mixer and mixed with the organic phase 1 in step (1), and then separated to obtain an organic phase 2 and alkali water 3; the alkali water 3 (the pH value of the alkali water 3 is controlled to be 12) is continuously introduced into a neutralization tubular reactor and washed with water to obtain an organic phase and alkali solution, and then separated to obtain an organic phase 1 and acesulfame potassium aqueous solution, i.e., sugar water, wherein the pH value of the sugar water is controlled to be 10.0, and the specific gravity of the sugar water is controlled to be 1.095 g / ml. The acesulfame potassium aqueous solution enters the sugar water tank for subsequent steps. After the sugar water solution is treated, the acesulfame potassium content in the finished product is 99.8%, and the yield of the neutralization step is 99.8%.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art can still modify or make equivalent substitutions to the specific implementation schemes of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention.

Claims

1. A step-by-step neutralization reaction method in the production process of acesulfame potassium, characterized in that: The steps include: (1) The water-washed organic phase obtained in the previous step and the alkali solution in the alkali solution tank are simultaneously and continuously pumped into a neutralization tubular reactor, and the water-washed organic phase and the alkali solution are passed through the neutralization tubular reactor to become organic phase 1; the organic phase 1 enters a neutralization tubular mixer, and the organic phase 1 is passed through the neutralization tubular mixer to become organic phase 2; Organic phase 2 enters the neutralization water washing tower, and becomes organic phase 3 after passing through the neutralization water washing tower. Organic phase 3 enters the extractant tank for extraction or is pumped to the subsequent stage for pre-steaming; (2) The alkaline solution 1 in the alkaline water tank is continuously pumped into the neutralization water washing tower and mixed with the organic phase 2 in step (1), and then separated to obtain an organic phase 3 and alkaline water 2; the alkaline water 2 is continuously pumped into the neutralization tubular mixer and mixed with the organic phase 1 in step (1), and then separated to obtain an organic phase 2 and alkaline water 3; the alkaline water 3 is continuously fed into the neutralization tubular reactor and mixed with the water-washed organic phase and the alkaline solution, and then separated to obtain an organic phase 1 and an aqueous solution of potassium acesulfame, and the aqueous solution of potassium acesulfame is fed into the sugar water tank for subsequent steps.

2. The reaction method according to claim 1, characterized in that: The alkali solution is a potassium hydroxide aqueous solution with a concentration of 10-15%.

3. The reaction method according to claim 2, characterized in that: The preparation method of the alkali solution is as follows: a potassium hydroxide solution with a concentration of 30% to 50% is mixed with water to prepare an alkali solution with a concentration of 10% to 15%.

4. The reaction method according to claim 3, characterized in that: The alkali solution is a potassium hydroxide aqueous solution with a concentration of 12%, 13% or 14%.

5. The reaction method according to claim 1, characterized in that: The alkaline water 1 is a potassium hydroxide aqueous solution with a concentration of 2-5%.

6. The reaction method according to claim 5, characterized in that: The preparation method of the alkaline water 1 is: a potassium hydroxide solution with a concentration of 30%-50% is mixed with water to prepare the alkaline water 1 with a concentration of 2-5%.

7. The reaction method according to claim 6, characterized in that: The concentration of the alkaline water 1 is 2%, 3% or 4%.

8. The reaction method according to claim 1, characterized in that: The pH of the alkaline water 2 is 12-13, and the pH of the alkaline water 3 is 11-12.

9. The reaction method according to claim 8, characterized in that: The pH value of the alkaline water 2 is 12, 12.5 or 13; the pH value of the alkaline water 2 is 11, 11.5 or 12.

10. The reaction method according to claim 1, characterized in that: The pH of the acesulfame potassium aqueous solution is 8.5-11, and the specific gravity of the acesulfame potassium aqueous solution is greater than or equal to 1.07 g / ml.

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