WO2022246870A1

WO2022246870A1 - Method for preparing acetoacetamide-n-sulfonic acid triethylamine salt

Info

Publication number: WO2022246870A1
Application number: PCT/CN2021/097018
Authority: WO
Inventors: 周睿; 丁震; 陈永旭; 杨峰宝; 刘刚
Original assignee: 安徽金禾实业股份有限公司
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2022-12-01
Also published as: CN113454060A; CN113454060B

Abstract

A method for preparing an acetoacetamide-N-sulfonic acid triethylamine salt, the method comprising: an amination reaction step, involving: dissolving sulfamic acid in first dichloromethane to obtain a first reaction solution; dissolving triethylamine in second dichloromethane to obtain a second reaction solution, and adding the second reaction solution into the first reaction solution for an amination reaction to form an ammonium sulfamate solution; and an acylation reaction step, involving: dissolving diketene in third dichloromethane to prepare a third reaction solution; filling a fixed bed reactor with a solid heteropolyacid catalyst, sequentially introducing the ammonium sulfamate solution and the third reaction solution into the fixed bed reactor and reacting same under preset conditions to form the acetoacetamide-N-sulfonic acid triethylamine salt. According to the method, a post-treatment process for the product is simplified, such that the final acesulfame potassium product has a better appearance; and the large-scale continuous production of an acetoacetamide-N-sulfonic acid triethylamine salt is achieved, the reaction time is shortened, the reaction yield is increased, and the production cost of acesulfame potassium is lowered.

Description

The preparation method of acetoacetamide-N-sulfonic acid triethylamine salt

technical field

The invention belongs to the technical field of fine chemicals, and in particular relates to a preparation method of acetoacetamide-N-sulfonic acid triethylamine salt.

Background of the invention

Acesulfame potassium (acesulfame potassium), also known as AK sugar, is a widely used sugar substitute food additive. Its appearance is white crystalline powder. As an organic synthetic salt, its taste is similar to sugarcane, and it is easily soluble in water. , Slightly soluble in alcohol, its chemical properties are stable, and it is not easy to break down and fail; it does not participate in the body's metabolism and does not provide energy; it has high sweetness and low price; it has no cariogenicity; it has good stability to heat and acid.

Acetoacetamide-N-sulfonic acid triethylamine salt is the important intermediate of producing acesulfame potassium, and the preparation method of this intermediate generally adopts diketene-sulfur trioxide method, and its specific reaction steps comprise: 1) making sulfamic acid Reaction with an amine to form the amine sulfamate salt, which is then reacted with diketene to form the acetoacetamide-N-sulfonic acid triethylamine salt.

The above reaction uses common sulfamic acid, diketene, triethylamine, etc. as raw materials. The reaction conditions are mild, the product yield is high, and the product purity is high. It is a relatively common industrialized method. However, since the acylation reaction between sulfamic acid amine salt and diketene is a strong exothermic reaction, diketene has a low flash point, and high-concentration diketene is prone to accidents at high temperatures. The addition acylation reaction must be carried out under strict temperature control conditions. , the reaction speed is slow, the reaction time is prolonged, and ice water cooling is required during the reaction process, which increases the reaction cost; the reaction requires a specific device, and the device cost and device maintenance cost are high; large-scale reactions cannot be completed in time and are not suitable for industrialization Continuous production. On the other hand, acetic acid needs to be added as a catalyst in the reaction process, which makes acetic acid impurities remain in the final product acesulfame potassium, resulting in poor color of acesulfame potassium and affecting people's experience in use.

The low flash point of diketene is also concerned in the prior art. Chinese patent application CN105198778A uses dichloromethane and diketene to increase the temperature of the acylation reaction, shorten the reaction time and improve the production efficiency. However, there are still problems of slow reaction speed, long reaction time, and low yield, which cannot meet the needs of large-scale continuous production; and still do not break away from the dependence on acetic acid.

Contents of the invention

In view of the above problems, the present application is proposed to provide a method for preparing acetoacetamide-N-sulfonic acid triethylamine salt that overcomes the above problems or at least partially solves the above problems.

According to one aspect of the present application, a kind of preparation method of acetoacetamide-N-sulfonic acid triethylamine salt comprises:

Amination reaction steps: dissolving sulfamic acid in the first dichloromethane to configure the first reaction solution; dissolving triethylamine in the second dichloromethane to configure the second reaction solution, adding the second reaction solution to Amination reaction is carried out in the first reaction solution to form ammonium sulfamate solution; and

Acylation reaction steps: dissolving diketene in the third dichloromethane to configure the third reaction solution; filling the solid-state heteropolyacid catalyst in the fixed-bed reactor, and feeding the ammonium sulfamate solution and The third reaction liquid reacts under preset conditions to form acetoacetamide-N-sulfonic acid triethylamine salt solution.

In some embodiments of the present application, in the above method, in the amination step, the ratio of the molar amount of sulfamic acid to the molar amount of the first dichloromethane is 1:6-15; the dissolution of sulfamic acid The temperature is 20-25°C.

In some embodiments of the present application, in the above method, in the amination reaction step, the ratio of the molar amount of triethylamine to the molar amount of the second dichloromethane is 1:1.5-2.5; -20 ℃ soluble in the second dichloromethane.

In some embodiments of the present application, in the above method, in the amination reaction step, the ratio of the mass consumption of sulfamic acid to the mass consumption of triethylamine is 1:1-1.2; the reaction temperature of the amination reaction is 20-30°C.

In some embodiments of the present application, in the above method, in the acylation reaction step, the ratio of the molar amount of diketene to the third dichloromethane is 1:1.5-2.5;

Diketene is soluble in tertiary dichloromethane at 10-20°C.

In some embodiments of the present application, in the above method, the ratio of the molar amount of sulfamic acid to the molar amount of diketene is 1:1-1.2, preferably 1:1.02-1.1.

In some embodiments of the present application, in the above method, in the acylation reaction step, the preset conditions are: the temperature is set to 20-35°C, preferably 25-30°C; the reaction time is set to 10-120s, preferably 30s -120s.

In some embodiments of the present application, in the above method, the solid heteropolyacid catalyst is a Keggin-type solid heteropolyacid catalyst.

In some embodiments of the present application, in the above method, the solid heteropolyacid catalyst with Keggin structure is H ₃ [PMo ₁₂ O ₁₄ ]·xH ₂ O solid catalyst.

According to another aspect of the present application, there is provided acetoacetamide-N-sulfonic acid triethylamine salt, which is prepared by any of the methods described above.

The beneficial effect of the present application is that the present application simplifies the product post-treatment process on the one hand by using a solid heteropolyacid catalyst combined with a fixed-bed reactor to replace the traditional organic acid catalyst combined with a reaction tank, so that the final product acesulfame K The appearance of the product is better, which significantly improves the user experience; on the other hand, the large-scale continuous production of acetoacetamide-N-sulfonic acid triethylamine salt has been realized, which greatly shortens the reaction time and improves the reaction yield. Therefore, the production cost of acesulfame potassium is reduced.

The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable , the following specifically cites the specific implementation manner of the present application.

Modes of Carrying Out the Invention

Exemplary embodiments of the present application will be described in more detail below. While an exemplary embodiment of the present application has been shown, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for thorough understanding of this application, and to fully convey the scope of this application to those skilled in the art.

The idea of the present application is that in the prior art, the intermediate acetoacetamide-N-sulfonic acid triethylamine salt for the preparation of acesulfame potassium has long reaction time, low reaction efficiency, low product yield, and difficulty in controlling the reaction temperature. The problem of providing a kind of preparation method of acetoacetamide-N-sulfonic acid triethylamine salt, is used for producing acetoacetamide-N-sulfonic acid triethylamine salt by combining a solid zeolite catalyst with a fixed bed reactor , can effectively overcome the above problems, realize continuous large-scale production, shorten the reaction time, and improve production efficiency.

The preparation method of acetoacetamide-N-sulfonic acid triethylamine salt of the present application comprises:

Amination reaction steps: dissolving sulfamic acid in the first dichloromethane to configure the first reaction solution; dissolving triethylamine in the second dichloromethane to configure the second reaction solution, adding the second reaction solution to Amination reaction is carried out in the first reaction solution to form ammonium sulfamate solution.

At first, be the preparation of ammonium salt of sulfamic acid, specifically, sulfamic acid and triethylamine are dissolved in methylene chloride respectively, sulfamic acid and triethylamine exothermic reaction, in the reaction process, the heat that produces will Part of the dichloromethane is vaporized, and the vaporized dichloromethane will leave the reaction system to take away the heat produced. Further, the vaporized dichloromethane can also be recycled.

The first reaction solution and the second reaction solution obtained by dissolving sulfamic acid and triethylamine in dichloromethane respectively are subjected to an amination reaction to obtain a sulfamic acid ammonium salt solution.

When the first reaction solution is mixed with the second reaction solution, it is best to gradually drop the second reaction solution into the first reaction solution, which can make the reaction more complete without causing excessive concentration of local reactants and excessive reaction .

Provide a kind of specific implementation that generates sulfamic acid ammonium salt solution below, and this embodiment is only as illustration, and the concrete production technology of sulfamic acid ammonium salt solution can adopt any one in the prior art. Accurately weigh according to the consumption ratio of preset sulfamic acid, the first dichloromethane, triethylamine and the second dichloromethane, open the metering tank valve of the reactivity and add the first dichloromethane in the dry reaction kettle, Start the stirring and circulating pump; put in sulfamic acid from the feeding hole. Close the circulation valve, open the feeding valve, send the mixed material in the melting tank to a dry synthesis tank, use circulating water to cool down, and wait until the temperature of the reactor drops to room temperature (about 20°C) to obtain the first reaction solution.

With the above process, obtain the second reaction solution in which triethylamine is dissolved in dichloromethane.

The second reaction liquid is added dropwise into the first reaction liquid. When the dropwise addition is completed, the pH value is 7-9, and the reaction is left to stand for 1 hour. The above-mentioned reacted material is ammonium sulfamate solution.

It should be noted here that in this application, the writing of the first dichloromethane, the second dichloromethane and the third dichloromethane appears, and the "first", "second" and "third" here are only As a distinguishing mark, it has no practical significance.

In some embodiments of the present application, by mixing dichloromethane with raw material sulfamic acid and triethylamine respectively, and then reacting with diketene dissolved in dichloromethane, dichloromethane can take away a large amount of heat of reaction on the one hand, It makes temperature control easier; on the other hand, it can increase the flash point of diketene and increase the reaction temperature of the entire reaction.

And acylation reaction step: dissolve diketene in the third methylene chloride to configure the third reaction solution; fill the solid-state heteropolyacid catalyst in the fixed-bed reactor, and feed the ammonium sulfamate solution into the fixed-bed reactor in turn React with the third reaction solution under preset conditions to form acetoacetamide-N-sulfonic acid triethylamine salt solution.

What select for use in this application is solid-state heteropolyacid catalyst, a class of heteropolyacid catalyst contains the catalyzer of the polynuclear coordination compound of oxygen bridge, there is certain gap between the heteropolyions in the bulk phase of solid-state heteropolyacid catalyst, makes Some molecules can go in and out, so that the solid heteropolyacid can successfully complete the catalytic process.

In this application, a solid heteropolyacid catalyst is used to replace the traditional acetic acid catalyst to provide acidic sites for the acylation reaction. On the one hand, it can effectively catalyze the acylation reaction of ammonium sulfamate and diketene. The heteropolyacid catalyst will not be mixed into the reaction product, and no special treatment process is required in the follow-up, which saves post-treatment economy and time cost; and avoids the acetic acid impurity that is not removed in the prior art remaining in the final product and affecting the final product. Adverse effects caused by appearance.

This application also adopts a fixed-bed reactor. In this application, the type and specification of the fixed-bed reactor are not limited. Anyone who can realize the fixation of the solid-state heteropolyacid catalyst does not need to provide a liquid acidic environment and does not introduce Impurities are sufficient, such as tubular fixed-bed reactors.

Fill the solid-state heteropolyacid catalyst in the fixed-bed reactor, set the fixed-bed reactor to the preset working state, first pass the sulfamic acid ammonium salt solution into the fixed-bed reactor, and wait for the sulfamic acid ammonium salt solution to flow normally After that, diketene is fed in the same direction, and by controlling the flow rate of the two, the contact time between the two is within the preset condition. At the same time, by controlling the heat exchange device of the fixed bed reactor, the reaction temperature is also within the preset condition. , when the preset reaction time is reached, the reaction can be ended to obtain the product acetoacetamide-N-sulfonic acid triethylamine salt solution. Due to the characteristics of the fixed bed reactor, the reaction can be carried out continuously and is suitable for large-scale industrial production.

Type and amount of solid heteropolyacid catalyst

In the present application, the type of heteropolyacid catalyst is not limited, any solid heteropolyacid catalyst that can provide acid sites can be; in some embodiments of the application, the solid heteropolyacid catalyst is Keggin type structure Solid-state heteropolyacid catalysts, mainly Keggin-type structures of 1:12 series such as H ₃ [PMO ₁₂ O ₁₄ ]·xH ₂ O, which have strong acidity and oxidizing properties, and their acidity is usually higher than that of each group of heteropolyacids The oxyacids contained in it have strong acidity, and when used as an oxidizing agent, it is easy to oxidize other substances, making itself in a reduced state and easy to regenerate. Therefore, the heteropolyacid catalyst can effectively catalyze the acylation of ammonium sulfamate and diketene on the one hand. The smooth progress of the reaction, on the other hand, significantly reduces the cost of the catalyst due to its strong regeneration ability, and further reduces the production cost of acesulfame potassium.

In this application, there is no limit to the amount of solid heteropolyacid catalyst used, which can be determined according to the specifications of the fixed-bed reactor.

The consumption ratio of sulfamic acid and the first dichloromethane

In the present application, in the amination reaction step, the ratio of the amount of sulfamic acid to the first dichloromethane is not limited, as long as the complete dissolution of sulfamic acid is ensured; in some embodiments of the present application Among them, considering economic factors, the ratio of the molar dosage of sulfamic acid to the molar dosage of the first dichloromethane is 1:6-15.

The dissolution temperature of sulfamic acid in the first dichloromethane is 20-25°C, that is, at room temperature. If the temperature is lower than 20°C or higher than 25°C, it only needs to be realized by specific means, although it is possible to achieve more Rapid dissolution, but requires a high economic cost, because the sulfamic acid is not difficult to dissolve, so it can be at room temperature.

The consumption ratio of triethylamine and the second dichloromethane

In the present application, in the above method, in the amination reaction step, the ratio of the amount of triethylamine to the second dichloromethane is not limited, as long as the complete dissolution of triethylamine is ensured; in this application Considering economical factors in some embodiments of the application, in the amination reaction step, the ratio of the molar usage of triethylamine to the molar usage of the second dichloromethane is 1:1.5-2.5.

The temperature at which triethylamine is dissolved in the second dichloromethane can be set at 10-20°C. Under low temperature conditions, it is beneficial to dissipate heat during the dissolution process.

The dosage ratio of sulfamic acid and triethylamine

In this application, in the amination reaction step, the ratio of the amount of sulfamic acid to triethylamine is not limited, and prior art can be referred to. In this application, in order to improve the conversion rate of sulfamic acid, a slight Excessive triethylamine, in some embodiments of the present application, the ratio of the mass usage of sulfamic acid to the mass usage of triethylamine is 1:1-1.2.

The reaction temperature of the amination reaction

In the present application, there is no limit to the temperature of the amination reaction, since the amination reaction does not need heating or cooling, it can be carried out at room temperature, and in some embodiments of the present application, it can be 20-30°C.

The consumption ratio of diketene and the third dichloromethane

In the present application, in the acylation reaction step, there is no limit to the amount ratio of diketene and the third dichloromethane, as long as the complete dissolution of diketene is ensured; in some embodiments of the application, considering the economic factor, the ratio of the molar amount of diketene to the molar amount of the third dichloromethane is 1:1.5-2.5.

The temperature at which diketene is dissolved in the third dichloromethane can be set at 10-20°C. Under low temperature conditions, it is beneficial to dissipate heat during the dissolution process.

The dosage ratio of sulfamic acid and diketene

In the present application, in the above method, in the amination reaction step, the ratio of the amount of sulfamic acid to triethylamine is not limited, and prior art can be referred to, such as in Chinese patent document CN112142687A, sulfamic acid and triethylamine The molar ratio n(sulfamic acid) of diketene:n(diketene)=1:1.0-1.5.

In the prior art, diketene needs a large amount of excess to achieve better technical results. In this application, due to the combination of solid-state heteropolyacid catalyst and fixed-bed reactor, sulfamic acid and diketene have greater contact area, to obtain a better mixing effect, so that the upper limit of the amount of diketene can be reduced relative to the prior art. The ratio is 1:1-1.2, and in other embodiments is 1:1.02-1.1, which can achieve better technical effects.

Preconditions

In this application, there is no limit to the preset conditions in the acylation reaction step, as long as there is no danger and can meet the reaction requirements of ammonium sulfamate solution and diketene; in some embodiments of the application , in the acylation reaction step, the preset conditions are: the temperature is set at 20-35°C; the reaction time is set at 10-120s. That is to say, the acylation reaction step of the present application is preferably carried out at a lower temperature, because dichloromethane can take away a large amount of heat, therefore, in the present application, temperature control is easier to achieve, using the prior art Any one of them can be used, such as air condensation technology, circulating water condensation technology and heat exchange plate. Since the combination method of the present application employs a solid heteropolyacid catalyst and a fixed-bed reactor, the reaction time of the acylation step can be significantly shortened, and the reaction can be completely completed within 10-120 seconds. If the reaction temperature is lower than 20°C and the reaction time is shorter than 10s, the reaction conditions are difficult to control, resulting in high reaction costs, too short contact time of raw materials, and incomplete reaction; if the reaction temperature is higher than 35°C and the reaction time is longer than 120s, then If the reaction temperature is too high, it is prone to danger, and the reaction time is too long, which increases the time cost and has no other beneficial effects; in other embodiments of the present application, in the acylation reaction step, the preset condition can preferably be: temperature Set it to 25-30°C; set the reaction time to 30-120s.

Drug or reagent source

In this application, each drug or reagent can be made by a laboratory or factory, or a commercially available product, which is not limited in this application.

Example 1 (including Example 1A, Example 1B, Example 1C, Example 1D, Example 1E)

Amination reaction steps: Dissolve 98kg of sulfamic acid and the first dichloromethane at a molar ratio of 1:6, and control the dissolution temperature at about 20-25°C to obtain a dichloromethane solution of sulfamic acid, that is, the first The reaction solution. Dissolution can be in a continuous mixing device or in a reactor.

Dissolving triethylamine and second dichloromethane at a molar ratio of 1:1, controlling the dissolution temperature to be 10-30°C to obtain a second reaction liquid, wherein the mass ratio of sulfamic acid to triethylamine is 1:1-1.2. Gradually add the second reaction solution dropwise into the reaction kettle where the first reaction solution is located for mixing and stirring, control the temperature of the system at 20-30°C, and control the system to be weakly alkaline, after mixing evenly, the ammonium sulfamic acid salt is obtained solution.

Embodiment 1A, embodiment 1B, embodiment 1C, embodiment 1D, embodiment 1E all comprise amination reaction step, in this reaction step, between each embodiment, the mass ratio of sulfamic acid and triethylamine changes, Please see Table 1 for details.

Acylation reaction step: dissolving diketene and third dichloromethane at a molar ratio of 1:1.5, controlling the dissolution temperature to 10-20° C. to obtain a third reaction solution.

After the solid heteropolyacid catalyst is installed in the fixed bed reactor, the fixed bed reactor is started, and the circulating water is adjusted to make the circulating water work normally.

Pass the sulfamic acid ammonium salt solution into the fixed-bed reactor, and after the sulfamic acid ammonium salt solution flows normally, pass the third reaction solution and the sulfamic acid ammonium salt solution into the fixed-bed reactor in the same direction to control amino The amounts of the ammonium sulfonate salt solution and the third reaction solution make the molar ratio of sulfamic acid to diketene 1:1.02-1.1. After the reaction starts, lower the temperature of the cooling water as much as possible, and control the temperature of the reaction system at 20-35°C; as the performance of the catalyst declines, the temperature can be slightly increased within the control range.

Control the flow rate of ammonium sulfamate solution and diketene, so that the reaction time is controlled between 10-120 seconds. The solution of the obtained target product acetoacetamide-N-sulfonic acid triethylamine salt is subjected to conventional methods such as suction filtration and crystallization to obtain the solid target product.

Embodiment 1A, embodiment 1B, embodiment 1C, embodiment 1D, embodiment 1E all comprise acylation reaction step, in this reaction step, between each embodiment, the molar ratio of sulfamic acid and diketene and reaction conditions exist change , see Table 1 for details.

It should be noted that, for the temperature values that appear in the above examples, since the reaction process is exothermic, it is enough to control the temperature within the above temperature range, and it is not necessary to accurately control it at a certain temperature. The present application can be realized within each embodiment, and will not be described one by one in each embodiment below.

Comparative Example 1 (comprising Comparative Example 1A and Comparative Example 1B)

Amination reaction step: 98kg of sulfamic acid and triethylamine are mixed and stirred in a reaction kettle with a mass ratio of 1:1, and the control system is weakly alkaline. After mixing evenly, the ammonium sulfamic acid solution is obtained.

The configuration of the dichloromethane solution of diketene: dissolve diketene and dichloromethane at a molar ratio of 1:8, and form the dichloromethane solution of diketene to form the third reaction solution.

Acylation reaction step: a fixed bed reactor was used, and no catalyst was used in this comparative example.

Pass the ammonium sulfamate solution into the fixed-bed reactor to control the flow rate of the ammonium sulfamate solution, pass the third reaction solution into the fixed-bed reactor to control the flow rate of diketene; after the reaction starts, try to lower the Cooling water temperature, the temperature of reaction system is controlled between 34 ℃-45 ℃. The solution of the obtained target product acetoacetamide-N-sulfonic acid triethylamine salt is subjected to conventional methods such as suction filtration and crystallization to obtain the solid target product. The results in Comparative Example 1 are listed in Table 1.

In Comparative Example 1, since the dichloromethane solution of diketene was used, the flash point was increased and the safety was improved. The acylation reaction is an exothermic reaction. When the reaction temperature rises to 40°C, dichloromethane begins to vaporize, thereby taking away part of the heat. Compared with the reaction controlled below the flash point of diketene, the overall reaction time is significantly reduced. Use Dichloromethane vaporization control temperature also has unreliable temperature control and because organic gas is not produced in a closed system reaction, it will produce and release a large amount of harmful gas, which is very poor in environmental friendliness.

It can be seen from Table 1 that in Comparative Example 1, the reaction needs to be maintained for a longer reaction time to obtain a higher yield, and longer reaction time and higher reaction temperature usually accompany more side reactions.

Comparative Example 2 (comprising Comparative Example 2A, Comparative Example 2B, Comparative Example 2C, Comparative Example 2D and Comparative Example 2E)

Amination reaction steps: 98kg of sulfamic acid and the first dichloromethane are dissolved in a molar ratio of 1:15, and the temperature of dissolution is controlled to be about 20-25°C to obtain the dichloromethane solution of sulfamic acid as the first reaction liquid. Dissolution can be in a continuous mixing device or in a reactor. Dissolving triethylamine and dichloromethane in a molar ratio of 1:1.2, controlling the dissolution temperature to be 10-30°C, to obtain a second reaction solution, wherein the mass ratio of sulfamic acid to triethylamine is 1: 1-1.2. Gradually drop the second reaction liquid into the reaction kettle where the first reaction liquid is located for mixing and stirring, and control the system to be weakly alkaline. After mixing evenly, the ammonium sulfamate solution is obtained.

Comparative Example 2A, Comparative Example 2B, Comparative Example 2C, Comparative Example 2D and Comparative Example 2E all comprise an amination reaction step, and in this reaction step, between each embodiment, the mass ratio of sulfamic acid and triethylamine varies, Please see Table 1 for details.

Acylation reaction step: adopt fixed-bed reactor, but do not use solid-state heteropolyacid molecular sieve.

Diketene and third dichloromethane were dissolved at a molar ratio of 1:2.0, and the temperature of dissolution was controlled to be 10-20°C to obtain a third reaction solution.

Add dropwise the amount of acetic acid calculated based on the sulfamic acid:acetic acid molar ratio of 1:0.05 in the sulfamic acid ammonium salt solution.

The sulfamic acid ammonium salt solution after adding acetic acid is passed in the fixed-bed reactor, controls the flow velocity of the sulfamic acid ammonium salt solution; The 3rd reaction liquid is passed in the fixed-bed reactor, controls the 3rd reaction liquid flow velocity; After the reaction starts, lower the temperature of the cooling water as much as possible, and control the temperature of the reaction system between 20-35°C; as the activity of the zeolite molecular sieve decreases, the temperature rises slightly within the control range.

Control the amount of sulfamic acid ammonium salt solution and diketene, calculated on the basis of the molar ratio of sulfamic acid and diketene in the sulfamic acid ammonium salt solution as 1:1-1.2; control the reaction time of the sulfamic acid ammonium salt solution and diketene, time control Between 10-120 seconds. The solution of the target product acetoacetamide-N-sulfonic acid triethylamine salt obtained obtains the solid target product through conventional methods such as suction filtration and crystallization. The results in Comparative Example 2 are listed in Table 1. As can be seen from Table 1, under the conditions of comparative example 2, because the reaction temperature is low, the reaction time is short (within 120s), the reaction is difficult to carry out thoroughly, and the recovery of acetoacetamide-N-sulfonic acid triethylamine salt The rate is very low and more impurities are introduced.

Table 1

Note: The yield is based on sulfamic acid, and the calculation method of the yield is the percentage of the mass of the target product acetoacetamide-N-sulfonic acid triethylamine salt to the mass of sulfamic acid.

As can be seen from Table 1, the solid-state heteropolyacid molecular sieve of Example 1, in the fixed-bed reactor, the reaction can be completed quickly, and the advantage of completing the reaction quickly is that under the same production capacity, a relatively small amount of diketene can be added at a time It can meet the needs of subsequent production. From the reaction point of view, the whole reaction time should not be too long, and the longer maintenance time will cause the decline of the overall yield.

In addition, it can be seen from Table 1 that the yield of the reaction in Example 1 is higher than that of Comparative Example 2 using acetic acid, and the reaction speed is obviously accelerated. In the reaction of Example 1, the amount of triethylamine shows that in the present application, under the condition of using a solid heteropolyacid catalyst, a higher yield can be obtained without a slight excess of amine. Moreover, the present application has short reaction time, low requirements on equipment, is suitable for industrial production, has high overall product yield, approximate molar ratio of raw materials, and less subsequent organic waste.

To sum up, this application simplifies the post-treatment process of the product on the one hand by using a solid heteropolyacid catalyst combined with a fixed-bed reactor to replace the traditional organic acid catalyst combined with a reaction tank. Better, it significantly improves the user experience; on the other hand, it realizes the large-scale continuous production of acetoacetamide-N-sulfonic acid triethylamine salt, which greatly shortens the reaction time and improves the reaction yield. Further, Reduced the production cost of acesulfame potassium.

The foregoing is only a specific implementation manner of the present application. Under the above teaching of the present application, those skilled in the art may make other improvements or modifications on the basis of the foregoing embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of the present application, and the protection scope of the present application should be based on the protection scope of the claims.

In addition, those skilled in the art will appreciate that although some embodiments described herein include some features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the present application. and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

Claims

A kind of preparation method of acetoacetamide-N-sulfonic acid triethylamine salt, it is characterized in that, comprises:

Amination reaction steps: dissolving sulfamic acid in the first dichloromethane to configure the first reaction solution; dissolving triethylamine in the second dichloromethane to configure the second reaction solution, adding the second reaction solution to Amination reaction is carried out in the first reaction solution to form ammonium sulfamate solution; and

Acylation reaction step: dissolving diketene in the third dichloromethane to configure the third reaction solution; filling a solid-state heteropolyacid catalyst in a fixed-bed reactor, and sequentially feeding the sulfamic acid into the fixed-bed reactor The ammonium salt solution and the third reaction solution react under preset conditions to form an acetoacetamide-N-sulfonic acid triethylamine salt solution.
The method according to claim 1, characterized in that, in the amination reaction step, the ratio of the molar dosage of the sulfamic acid to the molar dosage of the first methylene chloride is 1:6-15; The melting temperature of the sulfamic acid is 20-25°C.
The method according to claim 1, characterized in that, in the amination reaction step, the ratio of the molar dosage of the triethylamine to the molar dosage of the second methylene chloride is 1:1.5-2.5; The triethylamine is dissolved in the second dichloromethane at 10-20°C.
The method according to claim 1, characterized in that, in the amination reaction step,

The ratio of the mass dosage of the sulfamic acid to the triethylamine is 1:1-1.2; the reaction temperature of the amination reaction is 20-30°C.
The method according to claim 1, characterized in that, in the acylation reaction step, the ratio of the molar dosage of diketene to the molar dosage of the third dichloromethane is 1:1.5-2.5;

The diketene is soluble in the third dichloromethane at 10-20°C.
The method according to claim 1, characterized in that the ratio of the molar dosage of the sulfamic acid to the molar dosage of the diketene is 1:1-1.2, preferably 1:1.02-1.1.
The method according to claim 1, characterized in that, in the acylation reaction step, the preset conditions are: the temperature is set to 20-35°C, preferably 25-30°C; the reaction time is set to 10-120s , preferably 30-120s.
The method according to claim 1, wherein the solid-state heteropolyacid catalyst is a solid-state heteropolyacid catalyst of Keggin type structure.
The method according to claim 8, characterized in that the solid heteropolyacid catalyst with Keggin structure is H 3 [PMo 12 O 14 ]·xH 2 O solid catalyst.
An acetoacetamide-N-sulfonic acid triethylamine salt, characterized in that it is prepared by the method described in any one of claims 1-9.