Process for the preparation of high purity acetone

Abstract

The present application relates to the technical field of high-purity chemical reagent preparation, and in particular to a preparation method of high-purity acetone. The preparation method comprises: S1, performing first impurity removal treatment on crude acetone in the presence of an aqueous oxidizing agent solution to obtain a first product; S2, performing second impurity removal treatment on the first product in the presence of an alkali hydroxide solution, and then performing post-treatment to obtain high-purity acetone. The high-purity acetone prepared by the preparation method has high purity, low aldehyde content and low acid value, and can meet the requirements of IC manufacturing on the purity of acetone. In addition, the preparation method also has a high acetone recovery rate.

Description

Technical Field

[0001] This invention relates to the field of high-purity chemical reagent preparation technology, specifically to a method for preparing high-purity acetone. Background Technology

[0002] Acetone is an important organic solvent. It is a liquid at room temperature, colorless and transparent, and readily soluble in water and many organic solvents. It is chemically active and is an important raw material for the synthesis of chemicals such as ketenes, acetic anhydrides, iodoform, and epoxy resins.

[0003] High-purity acetone is one of the key raw materials in the manufacturing process of large-scale integrated circuits. Commercially available industrial-grade acetone, with a purity of up to 99.5%, contains trace amounts of unsaturated hydrocarbons and other organic impurities, as well as moisture, making it unsuitable for the purity requirements of IC manufacturing. Therefore, further purification of acetone to meet the needs of IC manufacturing and to satisfy the requirements for food and pesticide residue analysis is of great significance.

[0004] Reports on the preparation process of high-purity acetone are scarce, with most focusing on the recovery of acetone waste solvent. The few existing reports all have certain process limitations. For example, the paper "Research on the Preparation Process of High-Purity Acetone" reports the use of two-stage sub-boiling distillation to obtain high-purity acetone. However, this process has a low throughput, which cannot meet the needs of industrial production. Another example is the paper "Research on the Preparation Method of High-Purity Acetone," which uses an adsorption-drying-distillation process to obtain high-purity acetone. The resulting product has a high water content, with an acetone purity of only 99.9%. Yet another example is the paper "Research on the Purification Method of High-Purity Reagent Acetone," which only uses a drying-filtration-distillation method to obtain high-purity acetone. This method is not very effective at removing organic impurities, especially unsaturated organic impurities, which affects the purity of the acetone product.

[0005] Therefore, it is urgent to develop a method for preparing high-purity acetone, especially acetone products with high purity and low aldehyde and acid values. Summary of the Invention

[0006] The purpose of this invention is to provide a new method for preparing high-purity acetone, which yields a high-purity acetone product with low aldehyde content and acid value.

[0007] This invention provides a novel method for preparing high-purity acetone, comprising: S1 performing a first impurity removal treatment on crude acetone in the presence of an aqueous oxidizing agent to obtain a first product; S2 performing a second impurity removal treatment on the first product in the presence of an alkali metal hydroxide solution, followed by post-treatment to obtain high-purity acetone.

[0008] Through the above technical solution, the high-purity acetone prepared by the preparation method of the present invention has high purity, low aldehyde content and low acid value, which can meet the requirements of IC manufacturing for acetone purity. At the same time, the preparation method also has a high acetone recovery rate. Attached Figure Description

[0009] Figure 1 This is a schematic flowchart of a method for preparing high-purity acetone in one embodiment of the present invention.

[0010] Explanation of reference numerals in the attached figures

[0011] 1. Crude acetone 2. Aqueous solution of oxidizing agent 3. First product

[0012] 4. Alkali metal hydroxide solution; 5. Second product; 6. Third material

[0013] 7. Light components; 8. Distillation product; 9. Acetone product

[0014] 10. Recombinant components ①, First stirred tank ②, Second stirred tank

[0015] ③ Adsorption dehydration device ④ First distillation column ⑤ Second distillation column Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] In this invention, "purity" refers to a percentage by mass.

[0018] This invention provides a novel method for preparing high-purity acetone, the method comprising:

[0019] S1 performs a first impurity removal treatment on crude acetone in the presence of an aqueous solution of an oxidizing agent to obtain the first product.

[0020] S2 is used to perform a second impurity removal treatment on the first product in the presence of an alkali metal hydroxide solution, followed by post-treatment to obtain high-purity acetone.

[0021] In this invention, crude acetone is first treated with an aqueous solution of an oxidizing agent to remove impurities, then a second impurity removal process is performed using an alkali metal hydroxide solution, and finally a post-treatment is carried out to prepare high-purity acetone with a purity greater than 99.99%. Moreover, after undergoing multiple treatments, the crude acetone can still maintain a high acetone recovery rate.

[0022] According to the present invention, the aqueous solution of the oxidizing agent refers to an aqueous solution containing an oxidizing agent. The type of oxidizing agent is not particularly limited as long as the purpose of the present invention can be achieved. In some preferred embodiments, the aqueous solution of the oxidizing agent includes an acidic oxidizing agent and water. Using the foregoing embodiments can increase the purity of the final acetone product.

[0023] According to some preferred embodiments of the present invention, the acidic oxidant includes at least one of potassium permanganate, sodium dichromate, hydrogen peroxide, and potassium perchlorate.

[0024] According to some preferred embodiments of the present invention, the acidic oxidant is potassium permanganate and / or hydrogen peroxide.

[0025] According to the present invention, in some preferred embodiments, the acidic oxidant is [specific acid oxidant name]. By employing the foregoing embodiments, the purity of the final acetone product can be significantly increased.

[0026] According to some preferred embodiments of the present invention, the aqueous solution of the oxidizing agent further includes a stabilizer. Using the aforementioned embodiments, the stabilization and impurity removal of the acidic oxidizing agent can be better promoted, while also reducing the acid value of the final acetone product.

[0027] According to some preferred embodiments of the present invention, the stabilizer is selected from at least one of polyphosphates, poly(alkyl)acrylates, gluconates, and metasilicates. Using the aforementioned embodiments, the stabilization and impurity removal of the acidic oxidant can be better promoted, while also reducing the acid value of the final acetone product.

[0028] According to the present invention, the polyphosphates that can be listed include sodium pyrophosphate, the poly(alkyl) acrylates that can be listed include sodium polyacrylate, the gluconates that can be listed include sodium gluconate, and the metasilicates that can be listed include sodium metasilicate.

[0029] According to some preferred embodiments of the present invention, the stabilizer is at least one selected from sodium pyrophosphate, sodium polyacrylate, and sodium metasilicate. By employing the aforementioned embodiments, not only can the purity of the acetone product be increased and the acid value of the acetone product be reduced, but the recovery rate of acetone can also be increased.

[0030] According to the present invention, in some preferred embodiments, the stabilizer is sodium pyrophosphate. Using the aforementioned embodiments, the recovery rate of acetone can be increased more effectively.

[0031] According to some embodiments of the present invention, the alkali metal hydroxide solution contains at least one selected from lithium hydroxide, sodium hydroxide, and potassium hydroxide.

[0032] According to some preferred embodiments of the present invention, the content of the acidic oxidant in the aqueous solution of the oxidizing agent is 0.1-20 wt%, for example, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, or any range of two of the above values. Using the aforementioned embodiments, the purity of the final acetone product can be better increased.

[0033] According to some preferred embodiments of the present invention, the content of the acidic oxidant in the aqueous solution of the oxidizing agent is 1-10 wt%, preferably 1-5 wt%. Using the aforementioned embodiments, the purity of the final acetone product can be better increased.

[0034] According to some preferred embodiments of the present invention, the content of the stabilizer in the aqueous solution of the oxidizing agent is 0.1-20 wt%, for example, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, or any range of two of the above values. Using the aforementioned embodiments, the purity of the final acetone product can be better increased.

[0035] According to some preferred embodiments of the present invention, the stabilizer content in the aqueous solution of the oxidizing agent is 2-5 wt%. Using the aforementioned embodiments, the purity of the final acetone product can be better increased, and the recovery rate of the final acetone product can be increased.

[0036] According to the present invention, it is understood that an alkali metal hydroxide solution refers to a solution formed by dissolving an alkali metal hydroxide in a good solvent. As long as the purpose of the present invention can be achieved, the type of good solvent is not particularly limited, but water is preferred.

[0037] According to some preferred embodiments of the present invention, the molar concentration of the alkali metal hydroxide in the alkali metal hydroxide solution is 0.5-5 mol / L, for example, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, or any range of two of the above values. Using the aforementioned embodiments, the purity of the final acetone product can be better increased, and the acid value of the acetone product can be reduced.

[0038] According to the present invention, in some embodiments, the mass of the aqueous oxidizing agent is 0.1-1 wt% of the crude acetone mass, for example, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.7 wt%, 1 wt%, or any combination of two of the above values. Using the aforementioned embodiments, the purity of the final acetone product can be better increased, and the water content in the acetone product can be controlled.

[0039] According to the present invention, in some embodiments, the mass of the alkali metal hydroxide solution is 0.1-1 wt% of the crude acetone mass, for example, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.7 wt%, 1 wt%, or any combination of two of the above values. By employing the aforementioned embodiments, the purity of the final acetone product can be better increased, and the water content in the acetone product can be controlled.

[0040] According to some embodiments of the present invention, the acetone content in the crude acetone product is 98.5-99.9% by weight.

[0041] According to the present invention, crude acetone refers to an acetone product containing some impurities, wherein these impurities are generally water, alcohols, olefins, ethers, and ketones. In some embodiments, the crude acetone also contains at least one of water, isopropanol, acetaldehyde, propionaldehyde, propylene, isopropyl ether, methanol, and 4-hydroxy-4-methyl-2-pentanone. The method of the present invention can better reduce the content of the aforementioned possible impurities and increase the purity of the acetone product.

[0042] According to the present invention, the conditions for the first impurity removal treatment are not particularly limited as long as the purpose of the present invention can be achieved. In some embodiments, the conditions for the first impurity removal treatment include: a temperature of 15-50°C, for example, 15°C, 20°C, 30°C, 35°C, 40°C, 50°C, or any combination of two of the above values. By adopting the aforementioned embodiments, the purity of the final acetone product can be better increased, and the content of total aldehyde impurities in the acetone product can be reduced.

[0043] According to some preferred embodiments of the present invention, the conditions for the first impurity removal treatment include a temperature of 35-50°C. By employing the aforementioned embodiments, the purity of the final acetone product can be better increased, and the content of total aldehyde impurities in the acetone product can be reduced.

[0044] According to the present invention, the conditions for the first impurity removal process are not particularly limited as long as the purpose of the present invention can be achieved. In some embodiments, the conditions for the first impurity removal process include a time of 2-5 hours.

[0045] According to the present invention, the conditions for the second impurity removal treatment are not particularly limited as long as the purpose of the present invention can be achieved. In some embodiments, the conditions for the second impurity removal treatment include: a temperature of 15-50°C, for example, 15°C, 20°C, 30°C, 35°C, 40°C, 50°C, or any combination of two of the above values. By adopting the aforementioned embodiments, the purity of the final acetone product can be better increased and the acid value of the acetone product can be reduced.

[0046] According to the present invention, the conditions for the second impurity removal treatment are not particularly limited as long as the purpose of the present invention can be achieved. In some embodiments, the conditions for the second impurity removal treatment include a temperature of 15-40°C. By adopting the aforementioned embodiments, the purity of the final acetone product can be better increased and the acid value of the acetone product can be reduced.

[0047] According to the present invention, the conditions for the second impurity removal process are not particularly limited as long as the purpose of the present invention can be achieved. In some embodiments, the conditions for the second impurity removal process include a time of 0.5-2 hours.

[0048] The equipment used for the first and second impurity removal in this invention can be conventional equipment in the art, such as a stirred tank.

[0049] According to the present invention, the post-processing method is not particularly limited as long as it achieves the purpose of the present invention. Preferably, the post-processing includes dehydration, filtration, removal of light components, and removal of heavy components. Using the aforementioned embodiments can better increase the purity of the final acetone product.

[0050] According to the present invention, the dehydration method is not particularly limited as long as it achieves the purpose of the invention. In some embodiments, the dehydration method includes adsorption separation dehydration. Using the aforementioned embodiments, the water content in acetone products can be reduced more effectively.

[0051] The adsorption separation and dehydration in this invention refers to the use of an adsorbent to adsorb water from a material. In some preferred embodiments, the adsorbent used in the adsorption separation and dehydration includes molecular sieves and / or inorganic salt desiccants.

[0052] According to some preferred embodiments of the present invention, the adsorbent molecular sieve used in the adsorption separation and dehydration is combined with an inorganic salt desiccant. Using the aforementioned embodiments, it is possible to better reduce the water originally present in the crude acetone product and the water that may be introduced from the steps prior to dehydration, thereby reducing the water content in the acetone product and further reducing the acid value of the acetone product.

[0053] According to some preferred embodiments of the present invention, the molecular sieve is selected from at least one of type 3A molecular sieve, type 4A molecular sieve and type 5A molecular sieve, preferably type 5A molecular sieve.

[0054] According to some preferred embodiments of the present invention, the inorganic salt desiccant is selected from at least one of calcium chloride, soda lime, quicklime and sodium hydroxide solid, preferably calcium chloride.

[0055] According to some preferred embodiments of the present invention, the adsorption separation and dehydration method includes: at room temperature, the second product material is sequentially contacted with an inorganic salt desiccant and a molecular sieve. The aforementioned contact method can be a conventional method in the art, for example, an inorganic salt desiccant and a molecular sieve are sequentially loaded into an adsorption dehydration device, and the second product material enters the adsorption dehydration device for dehydration.

[0056] According to the present invention, the removal of impurities is mainly for the purpose of removing impurities with boiling points lower than those of acetone products. As long as the purpose of the present invention can be achieved, the conditions for the removal of impurities are not particularly limited. In some preferred embodiments, the conditions for the removal of impurities include an operating pressure of 100-200 kPa (absolute pressure).

[0057] The removal of light and heavy substances in this invention can be carried out in conventional distillation columns in the art.

[0058] According to the present invention, in some preferred embodiments, the conditions for removing light components include a reflux ratio of 2-20, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, or any combination of two of the above values. This can better increase the purity of the final acetone product.

[0059] According to some preferred embodiments of the present invention, the conditions for removing light components include a reflux ratio of 8-15. Using the aforementioned embodiments, the purity of the final acetone product can be better increased, while the recovery rate of the acetone product can also be increased.

[0060] According to some preferred embodiments of the present invention, the conditions for removing light components include: a bottom temperature of 56.6°C to 78.0°C.

[0061] According to the present invention, the deweighting treatment is mainly for removing impurities with boiling points higher than those of acetone products. As long as the purpose of the present invention can be achieved, the conditions for the deweighting treatment are not particularly limited. In some preferred embodiments, the deweighting conditions include an operating pressure of 100-200 kPa (absolute pressure).

[0062] According to some preferred embodiments of the present invention, the conditions for deweighting include: a reflux ratio of 0.2-5, for example, 0.2, 1, 2, 3, 4, 5, or any two of the above values.

[0063] According to some preferred embodiments of the present invention, the conditions for deweighting include: a tower top temperature of 55.7-77.5°C.

[0064] According to the present invention, such as Figure 1 As shown, in some embodiments, the preparation method of high-purity acetone includes: feeding industrial-grade crude acetone 1 into a first stirred tank ①, and simultaneously adding an aqueous solution of an oxidizing agent 2 (solvent being water) for a first impurity removal treatment to obtain a first product 3; feeding the first product 3 into a second stirred tank ②, and simultaneously adding an alkali metal hydroxide solution 4 for a second impurity removal treatment; feeding the second product 5 obtained from the second impurity removal treatment into an adsorption dehydration device ③, the adsorption dehydration device being filled with an adsorbent, and feeding the third material 6 from the dehydration device ③ into a first distillation column ④ for light component removal; removing light component 7 from the top of the first distillation column ④, and feeding the bottom product 8 of the first distillation column ④ into a second distillation column ⑤ for heavy component removal, the operating pressure (absolute pressure) for heavy component removal is 125 kPa, the reflux ratio is 2, and the top temperature is controlled at 62.4℃, finally obtaining high-purity acetone product 9 at the top of the second distillation column ⑤, and the bottom of the second distillation column ⑤ containing heavy component 10.

[0065] The present invention will be described in detail below through examples. In the following examples, the purity of the products was detected by HPLC, the moisture content was determined by Karl Fischer titration, and the acid value was determined by acid-base titration.

[0066] Example 1

[0067] like Figure 1 As shown, a batch of industrial grade crude acetone 1 was fed into the first stirred tank ①, wherein the purity of crude acetone 1 was 99.5%, the water content was 2500 ppm, and the total aldehyde content was 56 ppm. At the same time, 0.005 times (by mass of industrial grade crude acetone 1) of an aqueous solution 2 containing 5 wt% potassium permanganate and 5 wt% sodium pyrophosphate was added. The mixture was stirred at 40°C for 4 hours to carry out the first impurity removal treatment to obtain the first product.

[0068] The first product 3 was fed into the second stirred tank ②, and 0.005 times (by mass of industrial grade crude acetone 1) of a 3 mol / L sodium hydroxide alkali metal hydroxide solution 4 was added. The mixture was stirred at 25°C for 1 hour to carry out the second impurity removal treatment.

[0069] The second product 5 obtained from the second impurity removal process is fed into the adsorption dehydration device ③. The adsorption dehydration device is sequentially filled with inorganic desiccant calcium chloride and type 5A molecular sieve. The third material 6 coming out of the dehydration device ③ is fed into the first distillation column ④ for light removal. The operating pressure (absolute pressure) for light removal is 110 kPa, the reflux ratio is 10, and the column bottom temperature is controlled at 59.0℃.

[0070] Light component 7 is removed from the top of the first distillation column ④. The bottom product 8 of the first distillation column ④ is fed into the second distillation column ⑤ for heavy component removal. The operating pressure (absolute pressure) for heavy component removal is 125 kPa, the reflux ratio is 2, and the top temperature is controlled at 62.4℃. Finally, high-purity acetone product 9 is obtained from the top of the second distillation column ⑤, and the bottom of the second distillation column ⑤ contains heavy component 10.

[0071] Example 2

[0072] The method of Example 1 is followed, except that the aqueous solution of the oxidizing agent contains 2 wt% potassium permanganate and 5 wt% sodium pyrophosphate; the rest is the same as in Example 1, and a high-purity acetone product is finally obtained.

[0073] Example 3

[0074] The method of Example 1 is followed, except that the reflux ratio of the second distillation is 5; the rest is the same as in Example 1, and high-purity acetone product is finally obtained.

[0075] Example 4

[0076] The method of Example 1 is the same as in Example 1, except that the first impurity removal treatment is carried out by stirring at 5°C for 4 hours; the rest is the same as in Example 1, and finally a high-purity acetone product is obtained.

[0077] Example 5

[0078] The method of Example 1 is followed, except that the aqueous solution of the oxidizing agent contains only 5 wt% potassium permanganate; the rest is the same as in Example 1, and high-purity acetone product is finally obtained.

[0079] Example 6

[0080] The method of Example 1 is the same as in Example 1, except that the adsorption dehydration device is only filled with 5A molecular sieve; the rest is the same as in Example 1, and high-purity acetone product is finally obtained.

[0081] Example 7

[0082] The method of Example 1 is the same as in Example 1, except that the adsorption dehydration device is only filled with inorganic desiccant calcium chloride in sequence; the rest is the same as in Example 1, and high-purity acetone product is finally obtained.

[0083] Comparative Example 1

[0084] The method of Example 1 is the same as in Example 1, except that the first product material is directly fed into the adsorption and dehydration device for subsequent processing steps; the rest is the same as in Example 1, and acetone product is finally obtained.

[0085] Table 1

[0086]

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing high purity acetone, characterized by, The preparation method comprises: S1, a first impurity removal treatment is performed on the crude acetone in the presence of an aqueous oxidizing agent solution to obtain a first product; S2, a second impurity removal treatment is performed on the first product in the presence of an alkali metal hydroxide solution, and then a post-treatment is performed to obtain high-purity acetone; The post-treatment comprises dehydration, filtration, light removal, and heavy removal; The aqueous oxidizing agent solution further comprises a stabilizer selected from at least one of polyphosphate, polyalkyl acrylate, polyacrylate, gluconate, and metasilicate.

2. The preparation method according to claim 1, wherein The aqueous oxidizing agent solution comprises an acidic oxidizing agent and water; and / or The polyphosphate is selected from sodium pyrophosphate, and / or the polyacrylate is selected from sodium polyacrylate, and / or the gluconate is selected from sodium gluconate, and / or the metasilicate is selected from sodium metasilicate; and / or The alkali metal hydroxide in the alkali metal hydroxide solution is selected from at least one of lithium hydroxide, sodium hydroxide, and potassium hydroxide.

3. The production method according to claim 2, wherein, The acidic oxidizing agent comprises at least one of potassium permanganate, sodium dichromate, hydrogen peroxide, and potassium perchlorate.

4. The production method according to claim 3, wherein The acidic oxidizing agent is potassium permanganate and / or hydrogen peroxide.

5. The preparation method according to claim 2, wherein The content of the acidic oxidizing agent in the aqueous oxidizing agent solution is 0.1-20wt%; and / or The molar concentration of the alkali metal hydroxide in the alkali metal hydroxide solution is 0.5-5mol / L.

6. The production method according to claim 5, wherein The content of the acidic oxidizing agent in the aqueous oxidizing agent solution is 1-10wt%.

7. The production method according to claim 6, wherein The content of the acidic oxidizing agent in the aqueous oxidizing agent solution is 1-5wt%.

8. The production method according to claim 1, wherein The content of the stabilizer in the aqueous oxidizing agent solution is 0.1-20wt%.

9. The production method according to claim 8, wherein The content of the stabilizer in the aqueous oxidizing agent solution is 2-5wt%.

10. The preparation method according to claim 1, wherein The mass of the aqueous oxidizing agent solution is 0.1-1wt% of the mass of the crude acetone; and / or The mass of the alkali metal hydroxide solution is 0.1-1wt% of the mass of the crude acetone.

11. The preparation method according to claim 1, wherein The content of acetone in the crude acetone is 98.5-99.9wt%; The crude acetone further contains at least one of water, isopropyl alcohol, acetaldehyde, propionaldehyde, propylene, isopropyl ether, methanol, and 4-hydroxy-4-methyl-2-pentanone.

12. The preparation method according to claim 1, wherein The conditions of the first impurity removal treatment comprise a temperature of 15-50℃ and / or a time of 2-5h; and / or The conditions of the second impurity removal treatment comprise a temperature of 15-50℃ and / or a time of 0.5-2h.

13. The method of producing according to claim 1, wherein, The dehydration method comprises adsorption separation dehydration.

14. The production method according to claim 13, wherein The adsorbent in the adsorption separation dehydration comprises molecular sieves and / or inorganic salt driers.

15. The method of manufacturing according to claim 14, wherein, The adsorbent in the adsorption separation dehydration is a combination of molecular sieves and inorganic salt driers.

16. The preparation method according to claim 14 or 15, wherein The molecular sieves are selected from at least one of 3A-type molecular sieves, 4A-type molecular sieves, and 5A-type molecular sieves; and / or The inorganic salt desiccant is selected from at least one of calcium chloride, soda lime, quicklime and sodium hydroxide solid.

17. The preparation method according to claim 13, wherein, The method for adsorptive separation dehydration comprises: at normal temperature, the second product is sequentially contacted with the inorganic salt desiccant and the molecular sieve.

18. The preparation method according to claim 1, wherein, The conditions for removing light components comprise: The operating pressure is 100-200 kPa; and / or The reflux ratio is 2-20; and / or The column bottom temperature is 56.6-78.0℃.

19. The preparation method according to claim 1, wherein, The conditions for removing heavy components comprise: The operating pressure is 100-200 kPa; and / or The reflux ratio is 0.2-5; and / or The column top temperature is 55.7-77.5℃.

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