Synthesis method of hexafluoroisopropanol

Abstract

The present invention belongs to the technical field of fluorochemical industry, and particularly relates to a synthesis method of hexafluoroisopropanol. The synthesis method of hexafluoroisopropanol described in the present invention is as follows: First, 1,1,1-trifluoro-2-propanol is mixed with a solvent, and a catalyst is added with stirring. The temperature is raised to 65-75 °C, and then hexafluoroacetone gas is added at a rate of 45-75 g / min. After the addition is completed, the mixture is stirred and kept warm for reaction for 1-2 h. After the reaction is completed, a reaction solution is obtained. Finally, through rectification, the target product hexafluoroisopropanol is obtained. The molar ratio of the hexafluoroacetone to the 1,1,1-trifluoro-2-propanol is 1:1.05-1.12. The catalyst is aluminum tert-butoxide or aluminum isopropoxide. The synthesis method of hexafluoroisopropanol provided by the present invention has simple process operation and high safety. The reaction conditions are mild, the product has high purity, the target product is continuously withdrawn, the conversion rate of the reaction is high, the reaction activity is good, and the reaction efficiency is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorochemical industry, and particularly relates to a synthesis method of hexafluoroisopropanol. Background Art

[0002] Hexafluoroisopropanol (1,1,1,3,3,3 - hexafluoro - 2 - propanol) is an important fluorinated fine chemical, which can be used to prepare fluorinated surfactants, fluorinated emulsifiers, and fluorinated pharmaceuticals. As an important product in the fluorochemical industry, hexafluoroisopropanol benefits from the overall progress of fluorochemical technology, and its application fields are constantly expanding. With the rapid development of industries such as medicine, electronics, and cosmetics, the demand for hexafluoroisopropanol is increasing continuously. In the medical field, it can be used as an intermediate for the synthesis of inhaled anesthetic sevoflurane and anesthetic propofol; in the electronic field, it plays an important role as an electronic material; in the cosmetics field, it is used for the synthesis of some special components or as a solvent.

[0003] Currently, the main synthesis routes of hexafluoroisopropanol are: hydrogen reduction method of hexafluoroacetone trihydrate and catalytic method of hexafluoroepoxypropane. The hydrogen reduction method of hexafluoroacetone trihydrate is to first isomerize hexafluoroepoxy to hexafluoroacetone through a catalyst in a fixed bed, and then carry out a hydrogen reduction reaction. Although this synthesis process optimizes the utilization times of the catalyst and improves the reaction activity and conversion rate, it still uses a hydrogenation reduction reaction process and high - temperature conditions, and the process production is highly dangerous.

[0004] CN117285410A proposes to synthesize trifluoroacetaldehyde using trifluoroacetaldehyde dimethyl acetal as a raw material, and then synthesize hexafluoroisopropanol under the action of a trifluoromethylation reagent and a carbene catalyst. Although this process does not produce waste acid and shortens the reaction time, the purity of the synthesized product is relatively low, the process route is complex, and the subsequent production difficulty is increased.

[0005] CN113717030A proposes to prepare hexafluoroisopropanol by hydrogenation of hexafluoroacetone hydrate and hexafluoroisopropanol under the action of a catalyst. Although the reaction efficiency and the purity of hexafluoroisopropanol are improved by a specific reactor in this synthesis method, the production conditions of high temperature and high pressure exist in the reaction process, which greatly increases the potential safety hazards in the production process.

[0006] Therefore, the existing processes for synthesizing hexafluoroisopropanol mainly have problems such as many production process steps, cumbersome operations, too high reaction temperature and pressure, high requirements for the technical level of operators, many by - products in the reaction process, high subsequent rectification difficulty, and generally low production efficiency. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects existing in the prior art, and provide a synthesis method of hexafluoroisopropanol, which has simple process operation, high safety, mild reaction conditions, high product purity, continuous extraction of the target product, high reaction conversion rate, good reaction activity and high reaction efficiency.

[0008] The synthesis method of hexafluoroisopropanol described in the present invention: First, mix 1,1,1-trifluoroisopropanol with a solvent, stir and add a catalyst, heat up to 65-75 °C, and then add hexafluoroacetone gas at a rate of 45-75 g / min. After the addition is completed, stir and keep the temperature for reaction for 1-2 h. After the reaction is completed, a reaction solution is obtained, and finally, through rectification, the target product hexafluoroisopropanol is obtained.

[0009] The molar ratio of the hexafluoroacetone to 1,1,1-trifluoroisopropanol is 1:1.05-1.12.

[0010] The molar ratio of the hexafluoroacetone to the catalyst is 1:0.012-0.017.

[0011] The catalyst is aluminum tert-butoxide or aluminum isopropoxide.

[0012] The solvent is benzene, toluene, or isooctane.

[0013] The purity of the hexafluoroacetone is ≥99%.

[0014] The content of the 1,1,1-trifluoroisopropanol is ≥99.5%.

[0015] The rectification is carried out under atmospheric pressure, and trifluoroacetone and hexafluoroisopropanol are distilled out in turn.

[0016] The synthesis method of hexafluoroisopropanol described above adopts a synthesis device, which includes a reaction tank. The top of the reaction tank is connected to a packed tower, and the packed tower is connected to a condenser, and the condenser is connected to a condensation receiving tank.

[0017] The reaction tank is connected to a hexafluoroacetone gas tank. A circulation pipeline is arranged outside the reaction tank, and a circulation pump is arranged on the circulation pipeline.

[0018] The synthesis reaction of hexafluoroisopropanol in the present invention is a reversible reaction. By using the boiling point difference between the product and the bottom liquid, the product is continuously distilled out during the reaction process to ensure that the reaction proceeds in the desired forward direction. The synthesis route is as follows:

[0019] 。

[0020] Specifically, the synthesis method of hexafluoroisopropanol includes the following steps:

[0021] (1) Add the solvent and 1,1,1-trifluoro-2-propanol into the reaction tank and stir to mix. Then, add the catalyst into the reaction tank under stirring conditions, and raise the temperature of the solution in the reaction tank to 65 - 75°C. The temperature of the condenser is 0 - 5°C, and the temperature of the condensation receiving tank is 0 - 5°C.

[0022] (2) Turn on the circulation pump, spray and circulate the solution in the reaction tank from above the reaction tank, and then start to feed hexafluoroacetone gas into the reaction tank at a feeding rate of 45 - 75 g / min. Keep the temperature at 65 - 75°C during the feeding process. After the feeding is completed, continue to stir at this temperature for 1 - 2 h. After the reaction is completed, the reaction solution is obtained in the condensation receiving tank.

[0023] (3) Distill the reaction solution. Under normal pressure conditions, trifluoroacetone and hexafluoro-2-propanol are distilled out in turn, and finally, the target product hexafluoro-2-propanol is obtained in total.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The synthesis method of hexafluoro-2-propanol of the present invention reacts hexafluoroacetone gas with 1,1,1-trifluoro-2-propanol under the catalysis of a catalyst, avoiding the process risks generated by the hydrogen reduction reaction in the mainstream process. Moreover, the reaction conditions of this reaction are mild, the reaction situation is stable, and the danger is low. Then, the target product is continuously separated during the reaction process, ensuring the one-way progress of the reaction and allowing the reaction to proceed to the end to the greatest extent. Brief Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the synthesis device of hexafluoro-2-propanol of the present invention.

[0027] Figure 2 It is the gas chromatogram of the hexafluoro-2-propanol prepared in Example 3.

[0028] In the figure: 1. Hexafluoroacetone gas tank; 2. Reaction tank; 3. Packed tower; 4. Condenser; 5. Condensation receiving tank; 6. Circulation pump. Specific Embodiments

[0029] The present invention will be further described below in conjunction with specific embodiments.

[0030] The raw materials and auxiliaries used in the present invention are all commercially available products. The purity of the hexafluoroacetone used is 99%, and the content of 1,1,1-trifluoro-2-propanol is 99.5%.

[0031] Such as Figure 1As shown in the figure, the synthesis device of hexafluoroisopropanol includes a reaction tank 2. The top of the reaction tank 2 is connected to a packing tower 3. The packing tower 3 is connected to a condenser 4, and the condenser 4 is connected to a condensation receiving tank 5. The reaction tank 2 is connected to a hexafluoroacetone gas tank 1. A circulation pipeline is arranged outside the reaction tank 2, and a circulation pump 6 is arranged on the circulation pipeline.

[0032] The above device is used in each of the following examples.

[0033] Example 1

[0034] The synthesis method of hexafluoroisopropanol includes the following steps:

[0035] (1) Add 25.1 kg of toluene and 10.1 kg of 1,1,1-trifluoro-2-propanol into the reaction tank 2 and stir to mix. Then, under stirring conditions, add 0.33 kg of aluminum tert-butoxide into the reaction tank 2, and raise the temperature of the solution in the reaction tank 2 to 75 °C. The temperature of the condenser 4 is 0 °C, and the temperature of the condensation receiving tank 5 is 0 °C.

[0036] (2) Turn on the circulation pump 6 to spray and circulate the solution in the reaction tank 2 from above the reaction tank 2. Then start to feed hexafluoroacetone gas into the reaction tank 2 at a feeding rate of 73.3 g / min for a total of 3 h. The temperature is maintained at 75 °C during the feeding process. After the feeding is completed, continue to stir at this temperature for 2 h. After the reaction is completed, the reaction solution is obtained in the condensation receiving tank 5.

[0037] (3) Rectify the reaction solution. Under atmospheric pressure, trifluoroacetone and hexafluoro-2-propanol are distilled out in turn. Finally, a total of 12.36 kg of the target product hexafluoroisopropanol is obtained. Calculated according to the molar amount of hexafluoroacetone, its yield is 93.26%. Its purity is detected to be 99.73%.

[0038] Example 2

[0039] The synthesis method of hexafluoroisopropanol includes the following steps:

[0040] (1) Add 24.3 kg of benzene and 10.12 kg of 1,1,1-trifluoro-2-propanol into the reaction tank 2 and stir to mix. Then, under stirring conditions, add 0.206 kg of aluminum isopropoxide into the reaction tank 2, and raise the temperature of the solution in the reaction tank 2 to 65 °C. The temperature of the condenser 4 is 5 °C, and the temperature of the condensation receiving tank 5 is 5 °C.

[0041] (2) Turn on the circulation pump 6 to spray and circulate the solution in the reaction tank 2 from above the reaction tank 2. Then start to feed hexafluoroacetone gas into the reaction tank 2 at a feeding rate of 47.0 g / min for a total of 5 h. The temperature is maintained at 65 °C during the feeding process. After the feeding is completed, continue to stir at this temperature for 1 h. After the reaction is completed, the reaction solution is obtained in the condensation receiving tank 5.

[0042] (3) Rectify the reaction solution. Under atmospheric pressure, trifluoroacetone and hexafluoroisopropanol are distilled out successively. Finally, a total of 13.32 kg of the target product hexafluoroisopropanol is obtained. Calculated according to the molar amount of hexafluoroacetone, its yield is 94.12%. Its purity is detected to be 99.86%.

[0043] Example 3

[0044] The synthesis method of the hexafluoroisopropanol described above includes the following steps:

[0045] (1) Add 24.5 kg of benzene and 10.08 kg of 1,1,1-trifluorisopropanol to reaction tank 2, stir and mix them. Then, under stirring conditions, add 0.298 kg of aluminum tert-butoxide to reaction tank 2, and raise the temperature of the solution in reaction tank 2 to 70 °C. The temperature of condenser 4 is 2 °C, and the temperature of condensate receiving tank 5 is 2 °C.

[0046] (2) Turn on circulation pump 6 to spray and circulate the solution in reaction tank 2 from above reaction tank 2. Then, start to feed hexafluoroacetone gas into reaction tank 2 at a feeding rate of 56.4 g / min for a total of 4 h. During the feeding process, the temperature is maintained at 70 °C. After the feeding is completed, continue to stir at this temperature for 1.5 h. After the reaction is completed, a reaction solution is obtained in condensate receiving tank 5.

[0047] (3) Rectify the reaction solution. Under atmospheric pressure, trifluoroacetone and hexafluoroisopropanol are distilled out successively. Finally, a total of 13.05 kg of the target product hexafluoroisopropanol is obtained. Calculated according to the molar amount of hexafluoroacetone, its yield is 96.17%. Its purity is detected to be 99.91%. As Figure 2 shown.

[0048] Example 4

[0049] The synthesis method of the hexafluoroisopropanol described above includes the following steps:

[0050] (1) Add 25.5 kg of isooctane and 10.9 kg of 1,1,1-trifluorisopropanol to reaction tank 2, stir and mix them. Then, under stirring conditions, add 0.355 kg of aluminum tert-butoxide to reaction tank 2, and raise the temperature of the solution in reaction tank 2 to 65 °C. The temperature of condenser 4 is 0 °C, and the temperature of condensate receiving tank 5 is 0 °C.

[0051] (2) Turn on circulation pump 6 to spray and circulate the solution in reaction tank 2 from above reaction tank 2. Then, start to feed hexafluoroacetone gas into reaction tank 2 at a feeding rate of 59.3 g / min for a total of 4 h. During the feeding process, the temperature is maintained at 65 °C. After the feeding is completed, continue to stir at this temperature for 1.5 h. After the reaction is completed, a reaction solution is obtained in condensate receiving tank 5.

[0052] (3) Rectify the reaction solution, and distill out trifluoroacetone and hexafluoroisopropanol in turn under atmospheric pressure. Finally, a total of 13.65 kg of the target product hexafluoroisopropanol is obtained. The yield is calculated to be 95.43% according to the mol amount of hexafluoroacetone. Its purity is detected to be 99.70%.

[0053] Comparative Example 1

[0054] This comparative example is the same as Example 3, except that 0.298 kg of aluminum tert-butoxide in step (1) is removed, and other preparation process conditions are the same. Finally, a total of 2.21 kg of the target product hexafluoroisopropanol is obtained. The yield is calculated to be 8% according to the mol amount of hexafluoroacetone. Its purity is detected to be 49%.

[0055] Comparative Example 2

[0056] This comparative example is the same as Example 3, except that the temperature of reaction tank 2 in steps (1) and (2) is replaced with 20°C, and other preparation process conditions are the same. Finally, a total of 6.97 kg of the target product hexafluoroisopropanol is obtained. The yield is calculated to be 35% according to the mol amount of hexafluoroacetone. Its purity is detected to be 68%.

Claims

1. A method for synthesizing hexafluoroisopropanol, characterized in that: The following steps are involved: (1) Adding a solvent and 1,1,1-trifluoroisopropanol into a reaction tank and stirring to mix, then adding a catalyst into the reaction tank under stirring conditions, and raising the temperature of the solution in the reaction tank to 65-75°C, the temperature of the condenser to 0-5°C, and the temperature of the condensation receiving tank to 0-5°C; the catalyst is aluminum tert-butoxide or aluminum isopropoxide; (2) Turn on the circulation pump, spray the solution in the reaction tank from the top of the reaction tank for circulation, and then start to add hexafluoroacetone gas to the reaction tank at an acceleration of 45-75 g / min. The temperature during the addition process is maintained at 65-75 °C. After the addition is completed, continue to maintain the temperature and stir for 1-2 hours. After the reaction is completed, obtain the reaction liquid in the condensation receiving tank; (3) distilling the reaction solution, distilling trifluoroacetone and hexafluoroisopropanol in sequence under normal pressure conditions, and finally obtaining the target product hexafluoroisopropanol; The molar ratio of hexafluoroacetone to 1,1,1-trifluoroisopropanol is 1:1.05-1.

12.

2. The method for synthesizing hexafluoroisopropanol according to claim 1, characterized in that: The molar ratio of hexafluoroacetone to the catalyst is 1:0.012-0.

017.

3. The method for synthesizing hexafluoroisopropanol according to claim 1, characterized in that: The solvent is benzene, toluene or isooctane.

4. The method for synthesizing hexafluoroisopropanol according to claim 1, characterized in that: The purity of the hexafluoroacetone is ≥99%.

5. The method for synthesizing hexafluoroisopropanol according to claim 1, characterized in that: The content of 1,1,1-trifluoroisopropanol is ≥99.5%.

6. The method for synthesizing hexafluoroisopropanol according to claim 1, characterized in that: The rectification is to distill trifluoroacetone and hexafluoroisopropanol in sequence under normal pressure.

7. The method for synthesizing hexafluoroisopropanol according to claim 1, characterized in that: The synthesis device used comprises a reaction tank (2), the top of the reaction tank (2) is connected to a packing tower (3), the packing tower (3) is connected to a condenser (4), and the condenser (4) is connected to a condensation receiving tank (5).

8. The method for synthesizing hexafluoroisopropanol according to claim 7, characterized in that: The reaction tank (2) is connected to the hexafluoroacetone gas tank (1), a circulation pipeline is arranged outside the reaction tank (2), and a circulation pump (6) is arranged on the circulation pipeline.

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