New process method for synthesizing acesulfame potassium

Abstract

The invention discloses a novel process method for synthesizing acesulfame potassium, and belongs to the technical field of fine chemical organic synthesis. The process comprises the following steps: under the catalytic action of solid superacid, performing dehydration and ring closing on acetosulfamic acid triethylamine salt to generate cyclization liquid, layering and extracting the prepared cyclization liquid to obtain dichloromethane solution of acesulfamic acid, and neutralizing, concentrating, crystallizing and drying to obtain an AK product. Through the catalytic action of the solid superacid, the stability of the cyclization intermediate is improved, the quality of the product is effectively improved, the content of acesulfame potassium (AK) reaches 99.5% or above, meanwhile, the process conditions are mild, the catalyst is easy to recycle and separate, the production cost is saved, and industrial application is easy.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical synthesis, and particularly relates to a new process for synthesizing acesulfame potassium. Background Art

[0002] Acesulfame potassium has received extensive attention as the fourth-generation synthetic sweetener in the world. Acesulfame potassium is a colorless or white, odorless, crystalline powder with a strong sweet taste; it is easily soluble in water and slightly soluble in ethanol, and its sweetness is 200 times that of sucrose. Acesulfame potassium has light stability and thermal stability (can withstand high temperature of 225 °C), and has a wide pH value application range (pH = 3 - 7). It is one of the sweeteners with the best stability in the world at present and is applicable to baked foods, acidic beverages, jellies, desserts, etc.

[0003] At present, there are many reaction processes for synthesizing acesulfame potassium. Patent CN1154965A uses amidosulfuryl fluoride as a raw material, reacts with diketene to form acetoacetamidosulfuryl fluoride, and closes the ring under the catalysis of a base to obtain acetoacetesulfamic acid, and then reacts with potassium hydroxide to form potassium acetoacetesulfamate. However, this process needs to be carried out under a certain pressure, and the intermediate used has high toxicity and has been gradually replaced by other processes. Reacting aminosulfonic acid with diketene under the catalysis of triethylamine to form triethylamine acetoacetesulfamate, then using sulfur trioxide to close the ring to obtain acetoacetesulfamic acid, and then reacting with potassium hydroxide to obtain potassium acetoacetesulfamate. In this process, excessive sulfur trioxide reacts with water to generate a large amount of waste sulfuric acid, and the atom economy is low.

[0004] Solid superacid is a new type of catalytic material developed in recent years, and has good catalytic activity, selectivity and reusability for many chemical reactions. The acid strength of superacid is equivalent to that of sulfuric acid aqueous solution with a concentration of more than 100%, and it has the advantages of being easy to separate from reactants, reusable, and non-corrosive to reactors, etc. Summary of the Invention

[0005] The technical solution adopted by the present invention is as follows:

[0006] A new process for synthesizing acesulfame potassium, in which triethylamine acetoacetesulfamate dehydrates and closes the ring under the catalysis of solid superacid to form acetoacetesulfamic acid. Through the catalysis of solid superacid, the stability of the cyclization intermediate is improved, the quality of the product is effectively improved, and the content of acesulfame potassium reaches more than 99.5%. At the same time, the process conditions are mild, the catalyst is easy to recover and separate, the production cost is saved, and it is easy to be applied industrially.

[0007] The cyclization equation is shown as follows:

[0008]

[0009] The technical solution of the present invention is a new process for synthesizing acesulfame potassium. In this process, dichloromethane solution is added to the reactor for bottom laying, and the cyclization liquid prepared by adding the activated solid superacid catalyst and triethylamine salt solution of acetoacetic sulfanilic acid is subjected to layering and extraction to obtain the dichloromethane solution of sulfanilic acid (ACH), and then the AK product is obtained after neutralization, concentration, crystallization and drying.

[0010] According to a new process for synthesizing acesulfame potassium of the present invention, the mass content of DKA in the triethylamine salt solution of acetoacetic sulfanilic acid is 10-30%.

[0011] According to a new process for synthesizing acesulfame potassium of the present invention, after adding the activated solid superacid catalyst and triethylamine salt solution of acetoacetic sulfanilic acid to the reactor, stir for 10-50 min.

[0012] According to a new process for synthesizing acesulfame potassium of the present invention, the mass ratio of the addition amount of dichloromethane solution to the addition amount of solid superacid is 1-5:1; preferably 1-3:1.

[0013] According to a new process for synthesizing acesulfame potassium of the present invention, the solid superacid is SO4 2- / Fe2O3, SO4 2- / TiO2, SO4 2- / ZrO2 or SO4 2- / any one or any combination of SnO2 catalysts.

[0014] According to a new process for synthesizing acesulfame potassium of the present invention, the mass ratio of the addition amount of triethylamine salt solution of acetoacetic sulfanilic acid to the addition amount of solid superacid catalyst is 1:1-10; preferably 1:2-7.

[0015] According to a new process for synthesizing acesulfame potassium of the present invention, the activation temperature of the solid superacid catalyst is 300-600 °C; preferably, the activation temperature is 400-600 °C; for example, 400, 450, 500, 550, 600 °C.

[0016] According to a new process for synthesizing acesulfame potassium of the present invention, the activation time of the solid superacid catalyst is 1-8 h; preferably, the activation time is 1-4 h; for example, 1, 2, 3, 4 h.

[0017] According to a new process for synthesizing acesulfame potassium of the present invention, the reaction temperature is 0-60 °C; preferably 0-30 °C; for example, 0, 5, 10, 15, 20, 25, 30 °C.

[0018] Under the catalysis of solid superacid, triethylamine salt of acetoacetylsulfamic acid is dehydrated and cyclized to produce sulfamic acid, effectively improving the product quality, saving production costs and being easy for industrial application. Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0019] Under the catalytic conditions of the solid superacid catalyst of the present invention, the cyclization intermediate becomes stable and is not easily decomposed; this process does not require a hydrolysis step, simplifies the process conditions, increases the acesulfame content and improves the product quality; the process conditions are mild and the process is environmentally friendly, and the catalyst is easily separated and recovered after the reaction, making the catalytic process more environmentally friendly. Specific embodiments

[0020] The following examples describe the present invention in more detail. These examples are only descriptions of the implementation modes of the present invention and do not limit the protection scope of the present invention in any way.

[0021] The content of AK is in accordance with the national standard, and the formula is as follows:

[0022]

[0023] X1 - Content of potassium acesulfame, %;

[0024] c - Actual concentration of perchloric acid standard titration solution, in mol / L;

[0025] V1 - Volume of perchloric acid standard titration solution consumed by the sample, in mL;

[0026] V0 - Volume of perchloric acid standard titration solution consumed by the blank sample, in mL;

[0027] 0.2012 - Gram number of 1 mmol potassium acesulfame (C4H4KNO4S);

[0028] m1 - Mass of the sample (on dry basis), in g

[0029] Example 1

[0030] SO4 2- The SO4 2- / Fe2O3 solid superacid catalyst is placed in a muffle furnace at 550 °C for activation for 1 h, then cooled and taken out. 28.1 g of dichloromethane solution is added to the three-necked flask for bottom paving, and then stirred at a temperature of 5 °C. 28.2 g of SO4 2- / Fe2O3 solid superacid catalyst and 70.5 g of DKA solution were used, and the feeding rate was 5 g / min. After the raw materials were added, stirring was continued for 30 min, and then the sample was taken out and filtered to obtain a yellowish clear and transparent liquid. After neutralization, concentration, crystallization, and drying, the AK content reached 99.9%. Details are shown in Table 1.

[0031] Example 2

[0032] SO4 2- The SO4 2- / TiO2 solid superacid catalyst was placed in a muffle furnace at 500 °C for activation for 2 h, and then cooled and taken out. 72.5 g of dichloromethane solution was added to the three-necked flask for bottom laying, and then stirred at a temperature of 30 °C. Using a funnel, 72.5 g of SO4

[0033] Example 3

[0034] SO4 2- The SO4 2- / SnO2 solid superacid catalyst was placed in a muffle furnace at 400 °C for activation for 4 h, and then cooled and taken out. 169.2 g of dichloromethane solution was added to the three-necked flask for bottom laying, and then stirred at a temperature of 0 °C. Using a funnel, 84.6 g of SO4

[0035] Example 4

[0036] SO4 2- The SO4 2- / ZrO2 solid superacid catalyst was placed in a muffle furnace at 450 °C for activation for 3 h, and then cooled and taken out. 42.3 g of dichloromethane solution was added to the three-necked flask for bottom laying, and then stirred at a temperature of 25 °C. Using a funnel, 21.15 g of SO4

[0037] Example 5

[0038] SO4 2- The SO4 2- / SnO2 solid superacid catalyst was placed in a muffle furnace at 600 °C for activation for 1 h, then cooled and taken out. 84.6 g of dichloromethane solution was added to the three-necked flask for bottom laying, and then stirred at a temperature of 10 °C. 28.2 g of SO4

[0039] Example 6

[0040] SO4 2- / TiO2 solid superacid catalyst was placed in a muffle furnace at 400 °C for activation for 4 h, then cooled and taken out. 148.1 g of dichloromethane solution was added to the three-necked flask for bottom laying, and then stirred at a temperature of 20 °C. 49.35 g of SO4 2- / Fe2O3 solid superacid catalyst and 35.25 g of DKA solution were added using a funnel at a feeding rate of 5 g / min. After the raw materials were added, stirring was continued for 30 min, and then the sample was taken out and filtered to obtain a yellow clear and transparent liquid. After neutralization, concentration, crystallization, and drying, the AK content reached 99.7%. Details are shown in Table 1.

[0041] Table 1

[0042]

Claims

1. A new process for synthesizing acesulfame potassium, characterized in that, It includes the following steps: Add dichloromethane solution to the reactor for bottom laying, add the activated solid superacid catalyst and triethylamine salt solution of acetoacetic sulfanilic acid thereto, and the obtained cyclized liquid is subjected to layering and extraction to obtain the dichloromethane solution of sulfanilic acid (ACH), and then the AK product is obtained after neutralization, concentration, crystallization and drying.

2. The new process for synthesizing acesulfame potassium according to claim 1, characterized in that The mass ratio of the addition amount of the dichloromethane solution to the addition amount of the solid superacid is 1-5:

1.

3. The new process for synthesizing acesulfame potassium according to any one of claims 1-2, characterized in that The solid superacid described is SO4 2- / Fe2O3, SO4 2- / TiO2, SO4 2- / ZrO2 or SO4 2- / SnO2, any one of them or any combination thereof.

4. The new process for synthesizing acesulfame potassium according to any one of claims 1-3, characterized in that The mass ratio of the addition amount of the triethylamine salt solution of acetoacetic sulfanilic acid to the addition amount of the solid superacid catalyst is 1:1-10.

5. The new process for synthesizing acesulfame potassium according to any one of claims 1-4, characterized in that The activation temperature of the solid superacid catalyst is 300-600 °C; and / or the activation time is 1-8 h.

6. The new process for synthesizing acesulfame potassium according to any one of claims 1-5, characterized in that The reaction temperature is 0-60 °C.

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