CN1062560C - Method for separation and purification of acesulfame salt compounds - Google Patents

Abstract

A process for separating and refining dioxygen * thiazine salt includes such steps as adding extractant to the resultant mixture to make acidic product and extractant become ionic association, introducing it to organic phase, washing organic phase with water, using aqueous solution of inorganic alkali as back-extractant to convert the resultant into relative salt, returning it to water phase, concentrating the coarse product, and recrystallizing in the mixture of alcohol and water. The separation and refining method has the characteristics of simplicity, high efficiency, economy and practicability, can obtain high-purity dioxygen * thiazine salt, and is suitable for the production of sweeteners.

Description

Method for separation and purification of acesulfame salt compounds

Acesulfame has the following structure:

Among them, the hydrogen on the nitrogen atom has very strong acidity, and can be converted into salt when reacting with alkali, such as sodium salt, calcium salt, potassium salt, etc., especially potassium salt, referred to as AK sugar, which has been widely accepted as an edible low-calorie non-toxic food. Nutritious sweeteners are used. At present, there are many ways to synthesize this compound or its salt:

1. Fluorosulfonic acid acyl isocyanate reacts with 2-butyne or ethyl tert-butyl acetoacetate to generate 3-methyl acetoacetate fluorosulfonic acid amide, which is then cyclized to acid acetooxamic acid under alkaline conditions Zinc (Angewandle Chemie 85, lssue 22 (1973) pp 965-973).

2. Using acetoacetamide, sulfur trioxide and potassium hydroxide as raw materials [DE 3410440], in an inert organic or inorganic solvent, pass SO3 into acetoacetamide for cyclic condensation, and react to form acetoacetylsulfamic acid. converted to acesulfame under neutral conditions.

3. It uses sulfamic acid, triethylamine, diketene, sulfur trioxide and potassium hydroxide as raw materials. [DE 3410439] Dissolve sulfamic acid and dienone in an inert solvent, add triethylamine dropwise at about 0°C, and let stand overnight after reaction. Then, add SO3 at low temperature to carry out cyclization reaction to acid acesulfame.

4. Using acetoacetamide, potassium carbonate, sulfuryl fluoride and potassium hydroxide as raw _materials [JP-A-61/47473] Dissolve acetoacetamide and _K2CO3 in acetone aqueous solution, and introduce sulfur fluoride while stirring Acyl fluoride gas, carry out acetoacetylation reaction, after filtration, add the filter residue to 0 ℃ hydrochloric acid to make it undergo cyclization reaction to obtain acid acesulfame, then evaporate through solvent, extract with ethyl acetate, dry, and evaporate acetic acid Ethyl ester, and finally the potassium salt of acesulfame was precipitated with KOH in methanol.

5. Using sulfamic acid fluoride, diketene, potassium carbonate and potassium hydroxide as raw materials [JP-A-60/215661] adding diketene to an acetone solution containing H ₂ NSO ₂ F and K ₂ CO ₃ to obtain The potassium salt of acetoacetamido-N-sulfonyl fluoride was cyclized to the potassium salt with methanolic KOH.

Although the raw materials and reaction conditions used in these preparation methods are different, the method adopted in the last step is exactly the same, that is, the potassium salt of dioxathiazine is separated by direct precipitation with the methanol solution of potassium hydroxide as a salt agent. The above-mentioned direct salt-forming separation method has the following disadvantages: 1. Because all the solvents used in the reaction are low-boiling solvents, they have similar boiling points to the methanol introduced in the salt-forming separation step, so it is necessary to separate two or more solvents with similar boiling points. Because acetoacetylation reagents are used in the synthesis steps, these reagents generally require that the reaction solvent does not contain substances (such as methanol) with active hydrogen, so the methanol must be completely separated, and the complete separation of components with similar boiling points in industry is quite difficult. 2. The product of direct precipitation not only contains a large amount of inorganic salts, such as potassium fluoride, potassium sulfate, etc., but also contains other by-products that can precipitate with KOH and residual toxic methanol. Product purity is difficult to improve. The purpose of the present invention is to overcome the above-mentioned shortcomings existing in the existing methods, and propose a simple, efficient, economical and practical separation and purification method for obtaining high-purity acesulfame salt. Method of the present invention can be realized by following steps:

According to the above synthesis method, after the acetoacetylation and cyclization reactions, the reaction mixture obtained contains the following components: the main product acesulfame, sulfuric acid formed after the hydrolysis of excess sulfur trioxide, and a catalyst component Inorganic salts formed by separation of sulfuric acid, carbonic acid, fluoride, etc., and contain by-products and excess reactants of various reactions.

Add extractant to the above reaction mixture, extract at a temperature between -20 and +35°C, wash the organic phase with water, then use an aqueous solution of inorganic alkali as a stripping agent, and strip at a temperature between -20 and +35°C , make the pH of the aqueous solution after stripping be between 5～12, concentrate the precipitated crude product, carry out recrystallization refinement with the mixed solvent of ethanol:water=0%～50% (V/V).

Extractant of the present invention comprises following several classes:

(其中R1、R2代表C2～12的烷基、烷氧基或芳香基)(2)中性磷氧类萃取剂，结构通式：(其中R1、R2、R3代表C1～10的烷基、烷氧基或芳香基)(3)中性含硫萃取剂，结构通式：

(其中R1、R2代表C6～12的烃基或醚基)(4)胺类萃取剂，结构通式其中R1、R2、R3代表C5～12的烷基或酰基(1) acidic organophosphorus extractant, general structural formula:

(where R1 and R2 represent C2-12 alkyl, alkoxy or aromatic groups) (2) Neutral phosphorus-oxygen extractant, general structural formula: (where R1, R2, R3 represent C1-10 alkyl, alkoxy or aromatic groups) (3) Neutral sulfur-containing extractant, general structural formula:

(wherein R1 and R2 represent C6-12 hydrocarbon groups or ether groups) (4) amine extractant, general structure Where R1, R2, R3 represent C5-12 alkyl or acyl

The selected extractant should have the following characteristics in principle: (1) the acid form of acesulfame can form ionic associations and have a strong extraction ability, that is, the distribution coefficient is conducive to the content of the acid form product in the organic phase greater than its content in the aqueous phase. However, the metal salt of acesulfame has no extraction ability, that is, the product of the salt structure tends to be distributed in the water phase. (2) It has a higher boiling point, which is generally required to be 20°C higher than the boiling point of the reaction solvent (if the reaction uses a mixed solvent, the boiling point of the extractant should be 20°C higher than the component with the highest boiling point), and does not react with The solvent forms an azeotrope, thus, a simple distillation method can be used to recover the reaction solvent. (3) The solubility in water is small, preferably less than 1g/100ml, so as to avoid the obvious loss of the extractant itself during use. (4) It has good stability in acid and alkaline medium, and has good thermal stability at least below 100°C. Extractants with these characteristics include the following categories:

1. Acidic organophosphorus extractant: di(2-ethylhexyl) phosphoric acid, di(diisobutylmethyl) phosphoric acid, dodecyl phosphoric acid, 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester, phosphoric acid di Butyl ester, mono(2-ethylhexyl) phenylphosphonate, mono(1-methylheptyl) hexylphosphate, etc.

2. Neutral phosphorus oxygen extractant: triethyl phosphate, tripropyl phosphate, tributyl phosphate, triheptyl phosphate, trioctyl phosphate, triphenyl phosphate, dibutyl butyl phosphonate, dihexylmethyl Phosphonate, dimethylheptyl methylphosphonate, butyl dibutylphosphonate, tributylphosphine oxide, trioctylphosphine oxide, and the like.

3. Neutral sulfur-containing extractant: diheptyl sulfoxide, dioctyl sulfoxide, 3-hexylthiophene sulfoxide, etc.

4. Amine extractant: trioctylamine, triheptylamine, trilaurylamine, secondary amine, N, N'dimethylheptylacetamide, trialkylamine, etc.

The above extractants can be used alone or in combination. Some extractants are solid at normal temperature, so they can be dissolved in high-boiling organic solvents higher than 70°C, such as sulfonated kerosene, methyl acetone, 1,2-dichloroethane, etc. before use. The amount of extractant is mainly determined by the extraction efficiency, which is related to many factors, such as the pH of the aqueous phase, the temperature of the solution, the type of reaction solvent, and the characteristics of the extractant used, etc. The general amount should be 0.1 to 5 times that of the reaction solvent. The extraction should be carried out at a lower temperature to avoid the volatilization loss of the reaction solvent, generally controlled between -20 and +35°C, preferably between 0 and +20°C.

After extraction, the acidic aqueous phase was separated, and the organic phase was washed several times with water equivalent to about 1/10 of the volume of the organic phase until the washed water was tested with BaCl ₂ or AgNO ₃ solution (until no white precipitate was produced, that is to say The content of sulfate radical or fluoride ion in the organic phase is less than 0.1g/Kg) keep the organic phase for the next operation. The acid water phase is combined with the water used for washing, and the same amount of the same extractant as the first step is added for extraction. The extracted extractant contains a certain amount of acid products, which are used in the next cycle operation.

The solution used for stripping is an aqueous solution of the corresponding metal alkali or its carbonate. For preparing the potassium salt of acesulfame, an aqueous solution of potassium hydroxide or potassium carbonate is used. The consumption of alkali or carbonate is between pH 5～12 according to the acidity of the aqueous solution after stripping, preferably between pH 7～9.

The organic phase from the previous step was back-extracted with aqueous potassium hydroxide to convert the acidic product into the potassium salt and transfer to the aqueous phase. The concentration of potassium hydroxide aqueous solution can be changed in a wide range, and the upper limit is better that the water phase does not produce product precipitation after stripping, otherwise it is necessary to separate the precipitation first, and the lower limit is arbitrary, but the concentration of potassium hydroxide solution is too low. The concentration of the product in the aqueous phase after extraction is also necessarily low, and a large amount of water needs to be evaporated during the next step of concentration. The concentration of the best potassium hydroxide solution is to make the aqueous phase after stripping contain acesulfame potassium salt close to saturation. The pH of the aqueous phase after stripping should be between 5 and 12, preferably between 7 and 9. Then, the organic phase was washed with a small amount of water, and the washed water was incorporated into the aqueous phase obtained by stripping for the next step of concentration. The organic phase recovers the solvent and extractant by distillation.

The aqueous phase obtained in the previous step was concentrated by evaporation under reduced pressure. When evaporating, the vacuum can be controlled between 200-720mm column, preferably between 500-680mm mercury column. Control a certain heating temperature to keep the solution boiling evenly until a small amount of crystals are produced. The crude product obtained after cooling is used for the next step of refining.

The crude product was recrystallized using a mixed solvent of water and ethanol. Heat the solvent to about 70°C, dissolve the crude product while stirring until saturated, filter while it is hot, and cool the filtrate to room temperature naturally. A crystalline product precipitated out. Step 5 can be repeated as many times as needed. The ratio of water to ethanol can be determined according to specific conditions. The potassium salt of acesulfame has a high solubility in water, which increases with the increase of temperature, but the solubility in ethanol is very small, so the higher the content of ethanol in the mixed solvent, the more crystals will be precipitated after cooling. However, the smaller the treatment capacity is when heating, on the contrary, the greater the treatment capacity, but the greater the residual amount in the mother liquor. The ratio of the two is mainly determined according to the purity of the crude product and the temperature of the mother liquor after cooling. Ethanol: water (V/V) can be between 0% and 50%, preferably 10% to 30%.

Embodiment one

Add 100ml of di-(2-ethylhexyl)phosphoric acid to 100ml of acesulfame acidic reaction mixture (including organic phase and water phase), control the temperature at 30°C, extract for 10 minutes, and let it stand for about 5 minutes. The two phases are fully separated, and the water phase is separated. The content in the water phase and the organic phase is determined by high performance liquid chromatography, and the primary extraction rate is calculated to be 81.2%. Add 50ml of water to the washed organic phase, then add 5M potassium hydroxide solution in portions under the condition of vigorous stirring, so that the pH value of the water phase reaches about 6, separate the water phase after standing, and measure the water phase and The content of acesulfame potassium salt in the organic phase is calculated to be 75.6% in one back extraction rate.

Embodiment two

Add 100ml 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester to 100ml acesulfame acidic reaction mixture (including organic phase and aqueous phase), control the temperature at 18°C, and extract for 10 minutes , stand still to make the two phases fully separated, separate the water phase, and measure the content of the water phase and the organic phase with high performance liquid chromatography, and calculate the primary extraction rate to be 86.4%. Add 50ml of water to the organic phase after washing with water, then add 5M potassium hydroxide solution in portions under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 9, and measure the aqueous phase and organic phase after standing still. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 99.0%.

Embodiment three

Add 100ml of dodecylphosphoric acid to 100ml of acesulfame acidic reaction mixture (including organic phase and water phase), control the temperature at 23°C, extract for 10 minutes, and let stand for about 5 minutes to fully separate the two phases. Measured with the method of the above example, the calculated primary extraction rate is 53.0%. Add 50ml of water to the organic phase washed with clean water, and add saturated potassium carbonate solution in portions under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate the layers after standing, and measure the aqueous phase and the organic phase respectively. The content of acesulfame potassium salt in the medium is calculated as a back extraction rate of 98.0%.

Embodiment four

Add 100ml of dihexylmethylphosphonate to 100ml of acesulfame acidic reaction mixture (comprising organic phase and water phase), temperature is controlled at 23°C, extract for 10 minutes, let stand to make the two phases fully separated, Measured with the method of Example 2, the calculated primary extraction rate is 74.5%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 99.0%.

Embodiment five

Add 100ml of diethyldecyl phosphate to 100ml of acesulfame acidic reaction mixture (including organic phase and water phase), control the temperature at 20°C, extract for 10 minutes, let stand to make the two phases fully separated, and use Measured by the method of Example 2, the primary extraction rate is calculated to be 83.6%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 12, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 99.0%.

Embodiment six

Add 100ml of 20% trioctylphosphine oxide-sulfonated kerosene to 100ml of acesulfame acid reaction mixture (including organic phase and aqueous phase), control the temperature at 22°C, extract for 10 minutes, and let the two phases fully Layered, measured with the method of Example 2, the calculated primary extraction rate was 78.5%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 98.0%.

Embodiment seven

Add 50ml diethyldecyl phosphate and 50ml 20% trioctylphosphine oxide in 100ml acesulfame acidic reaction mixture (comprising organic phase and aqueous phase), temperature is controlled at 20 ℃, extracts 10 minutes, static The two phases are fully separated, measured by the method of Example 2, and the primary extraction rate is calculated to be 87.8%. Add 50ml of water to the organic phase washed with clear water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 12, separate after standing, and measure the aqueous phase and The content of acesulfame potassium salt in the organic phase is calculated to be 99.0% in one back extraction rate.

Embodiment eight

Add 100ml of triphenyl phosphate to 100ml of acesulfame acidic reaction mixture (including organic phase and water phase), control the temperature at 20°C, extract for 10 minutes, let stand to separate the two phases fully, and use Example 2 Method determination, calculation of a extraction rate of 57.5%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 99.0%. Embodiment nine

Add 100ml of 25% dioctyl sulfoxide-methyl acetone to 100ml of acesulfame acidic reaction mixture (including organic phase and aqueous phase), control the temperature at 20°C, extract for 10 minutes, and let the two phases fully separate Layer is measured by the method of Example two, and the primary extraction rate is calculated to be 43%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 97.0%.

Embodiment ten

Add 100ml of trialkylamine to 100ml of acesulfame acidic reaction mixture (including organic phase and water phase), control the temperature at 20°C, extract for 10 minutes, let stand to make the two phases fully separate, use Example 2 Method determination, the calculated primary extraction rate was 72.6%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 99.0%.

Embodiment Eleven

Add 100 ml of 3-hexylthiophene sulfoxide-1,2-dichloroethane to 100 ml of acesulfame acidic reaction mixture (including organic phase and aqueous phase), control the temperature at 20° C., and extract for 10 minutes. Stand still to make the two phases fully separated, measure with the method of Example 2, and calculate the primary extraction rate to be 39.5%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 97.0%.

Embodiment 12

Add 100ml of trioctylamine to 100ml of acesulfame acidic reaction mixture (including organic phase and water phase), control the temperature at 25°C, extract for 10 minutes, let stand to make the two phases fully separated, and use the method of Example 2 Determination, calculated primary extraction rate of 77.0%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in portions under vigorous stirring, so that the pH value of the aqueous phase reaches 7.5, separate the layers after standing, and measure the aqueous phase and organic phase respectively. The content of the potassium salt of acesulfame in the medium, calculated a stripping rate of 98.5%.

Embodiment Thirteen

Add 100ml of N,N-dimethylheptylacetamide to 100ml of acesulfame-containing acidic reaction mixture (including organic phase and aqueous phase), control the temperature at 20°C, and extract for 10 minutes. Stand still to make the two phases fully separated, measure with the method of Example 2, and calculate the primary extraction rate to be 63.5%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 98.5%.

Embodiment Fourteen

Add the mixed extractant of 50ml di(2-ethylhexyl) trialkylamine phosphate and 50ml phenylphosphonic acid in 100ml containing acesulfame acidic reaction mixture (comprising organic phase and aqueous phase), temperature is controlled at Extract at 20°C for 10 minutes. Stand still to make the two phases fully separated, measure with the method of Example 2, and calculate the primary extraction rate to be 90.3%. Add 50ml of water to the organic phase washed with water, and add 5M potassium hydroxide solution in batches under the condition of vigorous stirring, so that the pH value of the aqueous phase reaches about 8, separate after standing, and measure the aqueous phase and organic phase respectively. According to the content of acesulfame potassium salt in the phase, the once back extraction rate is calculated to be 99.0%.

Embodiment 15

The aqueous solution of acesulfame potassium salt obtained after the stripping treatment can be evaporated under reduced pressure, and the obtained concentrated solution is cooled to precipitate crude acesulfame potassium crystals, the purity of which can reach more than 95%. This crude product can obtain the refined product that purity is more than 99% with the refining method of this patent. Take 100 g of crude acesulfame potassium salt crystals, add in portions a mixed solution of ethanol and water containing 10% (V/V) ethanol to dissolve, dissolve all the crystals when they are close to the boiling point, and filter while hot. After the mother liquor was cooled, crystals were precipitated, and 84.5 g of refined product was obtained by suction filtration, and the refined yield was 88.9%.

Embodiment sixteen

Take 100 g of crude acesulfame potassium salt crystals, add in portions a mixed solution of ethanol and water containing 10% (V/V) ethanol to dissolve, dissolve all the crystals when they are close to the boiling point, and filter while hot. Crystals were precipitated after the mother liquor was cooled, and 89.4 g of refined product was obtained by suction filtration. The refined yield is 94.1%.

Embodiment 17

Take 100 grams of crude acesulfame potassium salt crystals, add in portions a mixed solution of ethanol and water containing 50% (V/V) ethanol to dissolve, dissolve all the crystals when they are close to the boiling point, and filter while hot. Crystals were precipitated after the mother liquor was cooled, and 93.8 g of refined product was obtained by suction filtration. The refined yield is 98.7%.

Embodiment eighteen

Take 100 grams of crude acesulfame potassium salt crystals, add pure water in portions, dissolve all the crystals at the boiling point, and filter while hot. After the mother liquor was cooled, crystals were precipitated and filtered by suction to obtain 74.6 g of a refined product. The refined yield is 78.5%.

Claims (16)

1. A method for separating and refining acesulfame salts, which is characterized in that it contains the main product acid acesulfame, sulfuric acid formed after hydrolysis of excess sulfur trioxide, and components as catalysts together with sulfuric acid and carbonic acid , inorganic salts generated by fluoride, and the synthetic reaction mixture of acesulfame containing various reaction by-products and excess reactants, adding acidic organophosphorus extractant, neutral phosphorus-oxygen extractant, neutral sulfur-containing Extractant or amine extractant, extract at a temperature between -20 and +35°C, wash the organic phase with water, then use an aqueous solution of inorganic alkali as a stripping agent, and strip at a temperature between -20 and +35°C to make the stripped The pH of the extracted aqueous solution is between 5 and 12, and the precipitated crude product is concentrated and purified by recrystallization with a mixed solvent with a volume ratio of ethanol and water of 0 to 50%. 2. separation and refining method according to claim 1, is characterized in that the structural general formula of described acidic organic phosphorus extractant is: Where R1 and R2 represent C2-12 alkyl, alkoxy or aromatic groups 3. The separation and refining method according to claim 1, characterized in that the general structural formula of the neutral phosphorus-oxygen extractant is:

Where R1, R2, R3 represent C1-10 alkyl, alkoxy or aromatic groups 4. separation and refining method according to claim 1, is characterized in that the structural general formula of described neutral sulfur-containing extractant is:

Among them, R1 and R2 represent C6-12 hydrocarbon groups or ether groups 5. separation and refining method according to claim 1, is characterized in that the general structural formula of described amine extractant is:

Where R1, R2, R3 represent C5-12 alkyl or acyl 6. separation and refining method according to claim 1, is characterized in that described acidic organophosphorus extractant is two (2-ethylhexyl) phosphoric acid, two (diisobutylmethyl) phosphoric acid, dodecyl phosphoric acid, 2- Mono(2-ethylhexyl) ethylhexylphosphonate, mono(2-ethylhexyl)phenylphosphonate, mono(1-methylheptyl)hexylphosphonate. 7. The separation and refining method according to claim 1, characterized in that said neutral phosphorus-oxygen extractant is triethyl phosphate, tripropyl phosphate, tributyl phosphate, triheptyl phosphate, trioctyl phosphate, Triphenyl phosphate, dibutyl butyl phosphonate, dihexyl methyl phosphonate, dimethyl heptyl methyl phosphonate, butyl dibutyl phosphonate, tributyl phosphine oxide, trioctyl phosphine oxide. 8. The separation and purification method according to claim 1, characterized in that the neutral sulfur-containing extractant is diheptyl sulfoxide, dioctyl sulfoxide, and 3-hexylthiophene sulfoxide. 9. The separation and refining method according to claim 1, characterized in that the amine extractant is triheptylamine, trioctylamine, trilaurylamine, N, N'-two (1-methylheptyl ) Acetamide. 10. separation and refining method according to claim 1, is characterized in that described extractant can be used alone, also can mix and use. 11. The separation and purification method according to claim 1, characterized in that the extractant can be dissolved in a high-boiling organic solvent higher than 70°C before use. 12. The separation and refining method according to claim 11, characterized in that the organic solvent of the extractant is sulfonated kerosene, methyl acetone, 1,2-dichloroethane. 13. The separation and purification method according to claim 1, characterized in that the temperature of the extraction and stripping is 0-20°C. 14. The separation and refining method according to claim 1, characterized in that the stripping agent in the aqueous inorganic alkali solution is potassium hydroxide or potassium carbonate aqueous solution. 15. The separation and purification method according to claim 1, characterized in that the pH of the aqueous solution after stripping is 7-9. 16. The separation and purification method according to claim 1, characterized in that the volume ratio of the mixed solvent of ethanol and water is 10-30%.