Preparation method of alcohol-free acetone

Abstract

The invention belongs to the field of chemical reagents, and particularly relates to a preparation method of alcohol-free acetone. The preparation method comprises the following steps: S1, carrying out primary adsorption by using a 4A molecular sieve and a 5A molecular sieve; s2, carrying out secondary adsorption by using a 4A molecular sieve, a 5A molecular sieve and a 10X molecular sieve; s3, adding sodium iodide into the acetone solution subjected to secondary adsorption treatment according to a solid-to-liquid ratio of 1: 4; s4, washing the crystal with absolute ether at least twice, then carrying out solid-liquid separation, and heating and distilling at 80-100 DEG C; s5, repeating S3 and S4, and carrying out secondary crystallization and crystal cleaning; s6, carrying out dehydration treatment on a crude product subjected to secondary distillation by using a 3A molecular sieve; and S7, carrying out rectification on the dehydrated crude product alcohol-free acetone in a temperature range of 80-100 DEG C. According to the technical scheme, before sodium iodide is added for adduct crystallization and purification, a step-by-step molecular sieve adsorption pretreatment process is introduced. According to the process, two molecular sieves with matched pore diameters and polarities are adopted, an industrial-grade acetone raw material is sequentially subjected to two times of adsorption treatment, and the purpose of synergistic purification is achieved by targeting different impurities.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical reagents, and particularly relates to a preparation method of alcohol-free acetone. BACKGROUND

[0002] As an important colorless transparent organic solvent and synthetic raw material, acetone has a special pungent odor, and its chemical properties are relatively active. It is easily soluble in water and can be mutually soluble with methanol, ethanol, ether, chloroform and pyridine and other organic solvents. In industry, acetone is currently mainly produced by the cumene method, and is widely used as a solvent in industries such as explosives, plastics, rubber, fibers, leather making, oil and fat, and paint spraying. At the same time, it is also an important raw material for synthesizing enone, acetic anhydride, iodoform, polyisoprene rubber, methyl methacrylate, chloroform and epoxy resin and other chemical products. In the field of analytical chemistry, especially as the mobile phase or solvent of high-end analysis such as high performance liquid chromatography (HPLC), the purity of acetone has a crucial influence on the accuracy of the analysis results.

[0003] With the continuous improvement of the quality requirements of chemicals in various industries, ordinary acetone products have been difficult to meet the stringent standards of solvent purity in high-end fields due to the presence of a small amount of alcohol impurities such as methanol, ethanol and isopropyl alcohol. In the existing purification technology, although the traditional method such as dehydrating treatment with anhydrous potassium carbonate followed by atmospheric distillation is simple in operation steps, the purity of the obtained product is limited and it is difficult to meet the quality requirements of HPLC grade acetone. Chinese patent CN107266300A discloses a purification method of acetone, which discloses the step of directly reacting industrial grade acetone with sodium iodide to form an adduct crystal to achieve purification. However, this technical solution has the defect that the raw material acetone is not effectively pretreated to remove specific impurities before the addition of sodium iodide. The organic impurities such as aldehydes and alcohols usually contained in industrial grade acetone may have side reactions with sodium iodide or extractants, or affect the crystallization purity and yield of the adduct during the subsequent formation of the adduct or extractive distillation. This defect may result in limited improvement of the purity of the final product, and may even introduce new impurities, while also reducing the effective utilization rate of sodium iodide, a key reagent, thereby restricting the purification efficiency and economy of the technical solution.

[0004] Since acetone and methanol can form azeotropes (azeotrope point about 55.5℃), and have high mutual solubility with ethanol, under the influence of the volatile characteristics of methanol, it is difficult to effectively separate trace amounts of methanol and other alcohol impurities from acetone. Therefore, there is an urgent need in the industry to develop a new purification process that is relatively simple in operation flow, low in energy consumption, economical in cost and can stably obtain high-purity acetone, in order to overcome the above-mentioned defects in the prior art and meet the application needs of high-end markets.

[0005] In addition, on the one hand, due to the difference in understanding of those skilled in the art; on the other hand, due to the fact that the inventors have studied a large number of literatures and patents when making the present invention, but limited by the size and have not listed all the details and contents in detail, however, this does not mean that the present invention does not have these prior art characteristics, on the contrary, the present invention has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art in the background art. SUMMARY

[0006] The present application belongs to the field of chemical reagents, and particularly relates to a preparation method of alcohol-free acetone.

[0007] In view of the above technical problems, the present application aims to provide a preparation method of alcohol-free acetone, which comprises the following steps: S1 adsorption is carried out once by 4A molecular sieve and 5A molecular sieve; S2 secondary adsorption is carried out by 4A molecular sieve, 5A molecular sieve and 10X molecular sieve; S3 sodium iodide is added into the acetone solution after the secondary adsorption treatment according to a solid-liquid ratio of 1:4; S4 after the crystal is cleaned with anhydrous ether for at least twice, solid-liquid separation is carried out, and heating distillation is carried out at 80-100 DEG C; S5 secondary crystallization and crystallization cleaning are carried out by repeating S3 and S4; S6 3A molecular sieve is used to carry out dehydration treatment on the crude product after the secondary distillation; S7 the alcohol-free acetone after dehydration is subjected to rectification at a temperature range of 80-100 DEG C.

[0008] According to a preferred embodiment, the 4A molecular sieve and the acetone have a feed liquid ratio of 1:33, in kg / L.

[0009] According to a preferred embodiment, the 5A molecular sieve and the acetone have a feed liquid ratio of 1:33, in kg / L.

[0010] According to a preferred embodiment, the 10X molecular sieve and the acetone have a feed liquid ratio of 1:100, in kg / L.

[0011] According to a preferred embodiment, in S1, the stirring after adding the molecular sieve is not less than 24 h. Preferably, the stirring after adding the molecular sieve is 24 h, and the operation is repeated twice.

[0012] According to a preferred embodiment, in S2, the stirring after adding the molecular sieve is not less than 24 h.

[0013] According to a preferred embodiment, in S3, the sodium iodide and the acetone have a feed liquid ratio of 1:4, in kg / L.

[0014] According to a preferred embodiment, in S3, after adding sodium iodide, the reaction solution is stirred at a temperature of 30-35 DEG C.

[0015] According to a preferred embodiment, in S4, heating and distillation are carried out at 80-90 DEG C.

[0016] According to a preferred embodiment, in S3, the completely stirred reaction solution is placed in an environment not lower than -15 DEG C for reaction crystallization.

[0017] The beneficial effects of the technical solution are: In order to solve the problem that a small amount of alcohol impurities are contained in acetone and the impurities such as methanol, ethanol and isopropyl alcohol cannot be separated by simple distillation at present, the present application provides a preparation method of alcohol-free propanol, which comprises the following operations: acetone is stirred and adsorbed on a molecular sieve for 24 hours, then filtered through a filtering device, and the operation is repeated twice. Then, sodium iodide is dissolved in acetone by stirring at 30-35 DEG C to obtain a sodium iodide acetone solution; after low-temperature crystallization of the solution, the solid is suction filtered, the solid crystal is washed with anhydrous ether, the solid is transferred into a distillation container for distillation, and the distillate is collected; the sodium iodide treatment is repeated twice to distill the distillate. The distillate treated twice is dehydrated with 3A molecular sieve, and after dehydration, the third distillation is carried out and the distillate is collected, so that the finished product is obtained.

[0018] The core improvement of the technical solution is that a step-by-step molecular sieve adsorption pretreatment process is introduced before the addition of sodium iodide for the crystallization and purification of the adduct. The process uses two molecular sieves with suitable pore size and polarity to adsorb the industrial-grade acetone raw material twice in turn, and through precise targeting of different impurities, the purpose of synergistic purification is achieved.

[0019] In the first stage of pretreatment, 3A molecular sieve with a pore size of 3A is used for adsorption once, and the pore size can accurately select and efficiently adsorb small-diameter water molecules, while effectively excluding the interference of acetone and other macromolecular impurities. This step creates a water-free environment for the formation of sodium iodide adduct, significantly improving the efficiency and product purity of the crystallization and purification step.

[0020] In the second stage, a molecular sieve with a moderately enlarged pore size is selected for secondary adsorption, which is specifically aimed at the small molecular alcohol impurities such as methanol, ethanol and isopropyl alcohol in the raw material. The molecular sieve can selectively adsorb alcohol molecules through its adapted pore structure and surface polarity, thereby effectively blocking the possibility of participating in azeotropic formation or interfering with the crystallization process in the subsequent process. This step not only improves the purity of the intermediate product, but also significantly reduces the separation load of the subsequent extractive distillation.

[0021] The step-by-step adsorption design significantly improves the purification efficiency and economy of the overall process by gradually purifying the impurities. While improving the purity of the final product, the consumption of sodium iodide and the extractant is reduced, energy consumption is saved, and the green production requirement is met due to the renewability of the molecular sieve. The entire technical solution thus has significant advantages in product quality, process stability, and industrial feasibility. DETAILED DESCRIPTION

[0022] In the description of the present application, the terms are used only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0023] Unless otherwise specified, the test methods used in the following examples are conventional methods; the materials, reagents or instruments used are commercially available reagents and materials; if the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used, and the source of the raw materials used in the present application is not limited. Unless otherwise specified, the raw materials used in the present application are ordinary commercially available products in the technical field.

[0024] The raw material acetone used in the following alcohol-free acetone preparation is an analytical pure acetone solution. The methanol content in the analytical pure acetone is 0.02% (mass fraction), and the content of ethanol and isopropanol is 0.002% (mass fraction).

[0025] Example 1 The present embodiment relates to a method for preparing alcohol-free acetone.

[0026] (1) First adsorption 10 L of acetone raw material was measured, 4A and 5A molecular sieves were added respectively, each adding 0.3 kg, 10X molecular sieve was added 0.1 kg, and stirring adsorption was carried out for 24 hours, and then filtration was carried out.

[0027] (2) Second adsorption The acetone after the first adsorption was added again to 4A and 5A molecular sieves, each adding 0.3 kg, and 10X molecular sieve was added 0.1 kg, and stirring adsorption was carried out for 24 hours, and then filtration was carried out.

[0028] (3) First crystallization of sodium iodide Sodium iodide was added to the acetone after the second adsorption treatment according to the solid-liquid ratio of 1:4 (4 L of acetone added with 1 kg of sodium iodide), and stirring was carried out at 30-35℃ to completely dissolve it, and then refrigerator crystallization was carried out.

[0029] (4) First washing and filtration distillation The crystallized product is separated from the liquid, then the crystals are washed twice with anhydrous ether, the solid is poured into a flask, and distillation is performed at a heating temperature of 80-100°C.

[0030] (5) Secondary crystallization of sodium iodide Sodium iodide is added to the product obtained by primary distillation at a solid-liquid ratio of 1:4 (4 L of acetone plus 1 kg of sodium iodide), and stirring is performed at 30-35°C until it is completely dissolved, and then freezing crystallization is performed in a refrigerator.

[0031] (6) Filtration and distillation after secondary washing The crystallized product is separated from the liquid, then the crystals are washed twice with anhydrous ether, the solid is poured into a flask, and distillation is performed at a heating temperature of 80-100°C.

[0032] (7) Dehydration with molecular sieves 5% (based on the mass of the crude product) of 3A molecular sieves are added to the crude product obtained by secondary distillation for dehydration.

[0033] (8) Distillation of the finished product The crude product after dehydration is subjected to distillation in anhydrous acetone at a heating temperature of 80-100°C.

[0034] Example 2 The preparation method of this example is identical to the preparation steps of Example 1 in (3)-(8), except that: (1) Primary adsorption 20 L of acetone raw material is measured, 4A, 5A molecular sieves are added at 0.6 kg each, and 10X molecular sieves are added at 0.2 kg, and stirring and adsorption are performed for 12 hours, and then filtration is performed.

[0035] (2) Secondary adsorption The acetone after primary adsorption is again added with 4A, 5A molecular sieves at 0.6 kg each, and 10X molecular sieves at 0.2 kg, stirring and adsorption are performed for 12 hours, and then filtration is performed.

[0036] Example 3 The preparation method of this example is identical to the preparation steps of Example 1 in (1), (2), (4)-(8), except that: (3) Primary crystallization of sodium iodide Sodium iodide is added to the acetone after secondary adsorption treatment at a solid-liquid ratio of 1:3 (3 L of acetone plus 1 kg of sodium iodide), and stirring is performed at 30-35°C until it is completely dissolved, and then freezing crystallization is performed in a refrigerator.

[0037] Example 4 The preparation method of this example is identical to the preparation steps of Example 1 in (1), (2), (4)-(8), except that: (3) Primary crystallization of sodium iodide Sodium iodide was added to the acetone after secondary adsorption treatment at a solid-liquid ratio of 1:5 (5 L of acetone and 1 kg of sodium iodide), and stirred at 30-35°C to completely dissolve, and then frozen and crystallized in a refrigerator.

[0038] Example 5 The preparation method of this example is consistent with the preparation steps of Example 1 in (1)-(6) and (8), except that: (7) Molecular sieve dehydration 3A molecular sieve was added to the crude product obtained by secondary distillation at a mass fraction of 10% (based on the total mass of the crude product) for dehydration treatment.

[0039] Example 6 The preparation method of this example is consistent with the preparation steps of Example 1 in (1)-(6) and (8), except that: (7) Molecular sieve dehydration 3A molecular sieve was added to the crude product obtained by secondary distillation at a mass fraction of 3% (based on the total mass of the crude product) for dehydration treatment.

[0040] Example 7 The preparation method of this example is consistent with the preparation steps of Example 1 in (1)-(5), (7), and (8), except that: (6) Second washing and filtration distillation After the crystallized product was separated by solid-liquid separation and dried, the solid was poured into a flask, and the heating temperature was set to 100°C for distillation.

[0041] Example 8 The preparation method of this example is consistent with the preparation steps of Example 1 in (1)-(5), (7), and (8), except that: (6) Second washing and filtration distillation After the crystallized product was separated by solid-liquid separation and dried, the solid was washed with anhydrous ether twice, and then poured into a flask, and the heating temperature was set to 100°C for distillation.

[0042] Comparative Example 1 The preparation method of this example is consistent with the preparation steps of Example 1 in (3)-(8), except that steps (1) and (2) are missing.

[0043] Comparative Example 2 The preparation method of this example is consistent with the preparation steps of Example 1 in (3)-(8), except that steps (1) and (2) are missing.

[0044] (1) Primary adsorption The once adsorbed acetone was added again to 4A and 5A molecular sieves each 0.4 kg, stirred and adsorbed for 24 hours, and then filtered.

[0045] (2) Second adsorption 10 L of acetone raw material was measured, and 4A and 5A molecular sieves each 0.4 kg were added, stirred and adsorbed for 24 hours, and then filtered.

[0046] Comparative Example 3 The preparation method of the present comparative example is consistent with the preparation steps of Example 1, and the difference lies in steps (1) and (2).

[0047] (1) First adsorption The once adsorbed acetone was added again to 4A and 5A molecular sieves each 0.4 kg, stirred and adsorbed for 24 hours, and then filtered.

[0048] (2) Second adsorption 10 L of acetone raw material was measured, and 4A and 5A molecular sieves each 0.4 kg were added, stirred and adsorbed for 24 hours, and then filtered.

[0049] Comparative Example 4 The preparation method of the present comparative example is consistent with the preparation steps of Example 1, and the difference lies in steps (1) and (2).

[0050] (1) First adsorption The once adsorbed acetone was added again to 4A and 5A molecular sieves each 0.4 kg, stirred and adsorbed for 24 hours, and then filtered.

[0051] (2) Second adsorption 10 L of acetone raw material was measured, and 4A and 5A molecular sieves each 0.4 kg were added, stirred and adsorbed for 24 hours, and then filtered.

[0052] The amount of molecular sieves added in each comparative example and example is shown in Table 1.

[0053] Table 1

[0054] The impurity content in the purified acetone solution of the comparative examples and examples is shown in Table 2.

[0055] Table 2

[0056] Compared with the comparative examples, the purity of the acetone product purified by the method of the present application (Example 1) is extremely high, and the contents of methanol and isopropanol are both reduced to "not detected", indicating that their concentrations are lower than the lower limit of instrument detection. In particular, the removal effect of ethanol is outstanding, and Example 1 reduces the content of ethanol to 0.0001%, which is much lower than the comparative examples (0.0002%-0.001%), achieving a significant reduction of an order of magnitude. This proves that the present method can simultaneously and efficiently remove multiple alcohol impurities, and exhibits a significant selective removal ability, ultimately obtaining an acetone product with a purity reaching the experimental grade.

[0057] It should be noted that the above specific examples are exemplary, and those skilled in the art can come up with various solutions under the inspiration of the disclosure of the present application, and these solutions also belong to the disclosed range of the present application and fall within the protection scope of the present application. Those skilled in the art should understand that the present application specification is illustrative and does not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for preparing alcohol-free acetone, characterized in that, Includes the following steps: S1 4A molecular sieve and 5A molecular sieve undergo one adsorption process; S2 4A molecular sieve, 5A molecular sieve and 10X molecular sieve are used for secondary adsorption; S3 Add sodium iodide to the acetone solution after the secondary adsorption treatment at a solid-liquid ratio of 1:4; After washing the crystals with anhydrous diethyl ether at least twice, solid-liquid separation is performed, followed by distillation at 80-100℃. S5 Repeat S3 and S4 to perform secondary crystallization and crystal cleaning; S6 3A molecular sieve is used to dehydrate the crude product after secondary distillation; S7 involves distilling the dehydrated crude alcohol-free acetone at a temperature range of 80-100℃.

2. The method for preparing alcohol-free acetone according to claim 1, characterized in that, The ratio of the 4A molecular sieve to the acetone solution is 1:33, with units of kg / L.

3. The method for preparing alcohol-free acetone according to claim 1, characterized in that, The ratio of the 5A molecular sieve to the acetone solution is 1:33, with units of kg / L.

4. The method for preparing alcohol-free acetone according to claim 1, characterized in that, The ratio of the 10X molecular sieve to acetone liquid is 1:100, with units of kg / L.

5. The method for preparing alcohol-free acetone according to claim 1, characterized in that, In S1, after adding the molecular sieve, stir for no less than 24 hours.

6. The method for preparing alcohol-free acetone according to claim 1, characterized in that, In S2, after adding molecular sieves, stir for no less than 24 hours.

7. The method for preparing alcohol-free acetone according to claim 1, characterized in that, In S3, the ratio of sodium iodide to acetone solution is 1:4, with units of kg / L.

8. The method for preparing alcohol-free acetone according to claim 1, characterized in that, In S3, sodium iodide is added and the reaction solution is stirred at a temperature of 30-35℃.

9. The method for preparing alcohol-free acetone according to claim 1, characterized in that, In S4, distillation is carried out at 80-90℃.

10. The method for preparing alcohol-free acetone according to claim 4, characterized in that, In S3, the fully stirred reaction solution is placed in an environment not lower than -15°C to carry out the reaction and crystallization.

Images