CN118702543B - Pentafluoropentanol and method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane - Google Patents

Abstract

The present invention belongs to the technical field of fluorine chemical industry, and in particular to pentafluoropentanol and a method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane. The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane of the present invention comprises the following steps: adding by-product pentafluorochloroethane to an ether solvent to obtain solution A; adding magnesium chips to an ether solvent to obtain solution B; adding 1/5-1/3 volume of solution A to solution B at 60°C to initiate a reaction; adding the remaining solution A to solution B, performing a Grignard reaction, and obtaining a pentafluoroethane magnesium chloride solution; cooling the pentafluoroethane magnesium chloride solution to 0°C, adding oxetane, performing a ring-opening reaction, and after the reaction is terminated, processing to obtain a crude pentafluoropentanol product; rectifying the crude pentafluoropentanol product to obtain pentafluoropentanol. The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane provided by the present invention saves costs, has an environmentally friendly process, has a fast reaction speed, and has a high yield of the synthesized pentafluoropentanol.

Description

Pentafluoropentanol and method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane

Technical Field

The invention belongs to the technical field of fluorine chemical industry, and specifically relates to pentafluoropentanol and a method for synthesizing pentafluoropentanol by utilizing by-product pentafluorochloroethane.

Background Art

Pentafluoropentanol, also known as 4,4,5,5,5-pentafluoropentanol, is a colorless liquid with a molecular weight of 178.1, a boiling point of 62°C-64°C, a density of 1.35g/mL, and a structural formula of .

Pentafluoropentanol is a key intermediate of Fulvestrant (estrogen receptor antagonist). This compound is also an important raw material for surfactants, dyes and functional material monomers, and is widely used. There are four main synthesis methods: one is to synthesize pentafluoropentanol by reduction using 4,4,5,5,5-pentafluoro-2-iodo-1-pentanol or 4,4,5,5,5-pentafluoro-2-iodopent-2-ene-1-ol as raw materials. The second is to use 3-bromo-1,1,1,2,2-pentafluoropropane as raw material to make Grignard reagent, and then open the ring with ethylene oxide and acidify to synthesize pentafluoropentanol. The third is to use pentafluoroiodoethane as raw material and allicinol, in the presence of catalysts and ligands, to synthesize pentafluoropentanol. The fourth is to use 1,1,1,2,2-pentafluoropentane as raw material, and react with isopropylbenzene hydroperoxide in the presence of a catalyst to synthesize pentafluoropentanol. However, the above methods all have their own shortcomings.

Patent publication CN111004091A mentions that in the presence of a loaded precious metal composite catalyst Pt/AlF ₃ , a solvent and an oxidant, the reaction is carried out at 80°C for 2 hours to catalyze and oxidize 1,1,1,2,2-pentafluoropropane to synthesize pentafluoropentanol in one step, which has the advantages of simple reaction operation and high selectivity. However, the platinum catalyst used is expensive and has high cost, which limits its large-scale industrial application.

Patent publication CN114853568A mentions that the catalyst and ligand are dissolved in an organic solvent at room temperature, reacted for a certain period of time, and then allyl alcohol, alkali, fluorine source and hydrogen donor are added to react to obtain 4,4,5,5,5-pentafluoropentanol. This route has advantages such as environmental protection, but it requires the preparation of catalysts and ligands in advance, the operation is cumbersome, and allyl alcohol is a highly toxic substance, which is inconvenient to operate and has great risks.

The preparation method of pentafluoropentanol mentioned in the patent CN107501044A, and the paper published by Williams, Jason et al. in Organic Letters (2019, vol. 21, 13, p. 5341-5345) in 2019, allyl alcohol and pentafluoroiodoethane or pentafluorobromoethane are used as raw materials, and 4,4,5,5,5-pentafluoro-2-bromo-1-pentanol or 4,4,5,5,5-pentafluoro-2-iodo-1-pentanol is synthesized by free radical initiator, and then pentafluoropentanol is obtained by dehalogenation reaction catalyzed by transition metal catalyst. The free radical initiator used in this process is not easy to control the reaction, and there will be a high safety risk in mass production.

In 1994, Shankar M. Singh et al. published in Tetrahedron Letters (Tetrahedron Letters, 1994, vol. 35, #49, p. 9141-9144) that in the presence of sodium bisulfite, perfluoroethyl iodide was subjected to quantitative free radical addition to propargyl alcohol to obtain E/Z-2-iodo-4,4,5,5,5-pentafluoro-2-pentene-1-ol, which was converted into 4,4,5,5,5-pentafluoropentane-1-ol in one step by catalytic hydrogenation of platinum oxide in the presence of triethylamine. This route uses expensive Pt catalysts and is not suitable for industrialization.

Patent CN116162016A mentioned that propionyl chloride is used as raw material, and the generated perfluoropropionyl fluoride reacts with sodium borohydride and methanol to generate 2,2,3,3,3-pentafluoropropanol, 2,2,3,3,3-pentafluoropropanol and phosphorus tribromide undergo substitution reaction to generate 1-bromo-2,2,3,3,3-pentafluoropropane, 1-bromo-2,2,3,3,3-pentafluoropropane reacts with magnesium powder to generate Grignard reagent, and reacts with ethylene oxide to generate crude pentafluoropentanol, and high-purity pentafluoropentanol is obtained by distillation. The sodium borohydride and phosphorus tribromide used have great safety risks in industrial use, and the price of sodium borohydride is relatively expensive.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane, which saves costs, is environmentally friendly, has a fast reaction speed, and has a high yield of the synthesized pentafluoropentanol.

The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane of the present invention comprises the following steps:

(1) Add the by-product pentafluorochloroethane into the solvent to obtain solution A with a mass fraction of ≥5%;

(2) Add magnesium chips to an ether solvent to obtain solution B with a mass fraction of ≥5%;

(3) At 40°C-80°C, add 1/5-1/3 volume of solution A to solution B at a rate of 50 mL/min to initiate the reaction;

(4) adding the remaining solution A to solution B at a rate of 30 mL/min to carry out a Grignard reaction to obtain a pentafluoroethane magnesium chloride solution;

(5) Cooling the pentafluoroethane magnesium chloride solution to -10°C to 0°C, adding oxetane to carry out a ring-opening reaction, and after the reaction is completed, treating to obtain a crude pentafluoropentanol;

(6) The crude pentafluoropentanol is distilled to obtain pentafluoropentanol.

The molar ratio of the by-product pentafluorochloroethane to the magnesium chips is 1:(1-2), preferably 1:1.2.

The molar ratio of the theoretical output of pentafluoroethane magnesium chloride to oxetane in step (5) is 1:(1-1.2), preferably 1:1.05.

The solvent in step (1) and step (2) is one of an ether solvent or a hydrocarbon solvent, the ether solvent is tetrahydrofuran or diethyl ether, and the hydrocarbon solvent is one of benzene, toluene, n-hexane, and cyclohexane.

The temperature of the initiation reaction controlled in step (3) is 40-70°C and the time is 5-30 minutes.

The Grignard reaction temperature of step (4) is 30°C-60°C, preferably 60°C, and the reaction time is 8h-12h, preferably 8h.

The treatment steps described in step (5) are: depressurizing the solution after the reaction is completed, quenching with water, and distilling.

The distillation temperature is 60°C-70°C.

The temperature of the ring-opening reaction in step (5) is 30°C-50°C, preferably 30°C, and the reaction time is 2h-4h, preferably 2h.

Step (6) distillation, collecting the fraction at 62°C-64°C.

A pentafluoropentanol is synthesized by utilizing the method for synthesizing pentafluoropentanol by utilizing by-product pentafluorochloroethane.

Specifically, the method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane comprises the following steps:

(1) Add the by-product pentafluorochloroethane into 3 L of anhydrous solvent to obtain solution A;

(2) Install a condenser and a dropping funnel on the high-pressure reactor, add magnesium chips and anhydrous ether solvent, and mix to obtain solution B;

(3) At 40°C-80°C, add 1/5-1/3 volume of solution A to solution B at a rate of 50 mL/min to initiate the reaction, start stirring and reflux to cool down, and control the reaction temperature to 40-70°C and the reaction time to 5-30 min;

(4) adding the remaining solution A to solution B at a rate of 30 mL/min, and carrying out a Grignard reaction at 30°C-60°C for 8h-12h to obtain a pentafluoroethane magnesium chloride solution;

(5) Cool the pentafluoroethane magnesium chloride solution to -10°C-0°C, add oxetane at 1 drop/s, and carry out a ring-opening reaction at 30°C-50°C for 2h-4h. After the reaction is completed, release the pressure, add 500g of water to quench, and distill at 60-70°C to obtain a crude pentafluoropentanol;

(6) The crude pentafluoropentanol is added to a distillation tower for distillation, and the fraction at 62° C.-64° C. is collected to obtain high-purity pentafluoropentanol.

The invention firstly introduces pentafluorochloroethane into a dry ether solvent, slowly adds the solvent into a reaction container containing magnesium chips and the ether solvent to prepare pentafluoroethane magnesium chloride through a Grignard reaction, then slowly adds oxetane into the prepared Grignard reagent, performs ring opening by heating, quenching, crude distillation and finally rectification to obtain the final product pentafluoropentanol.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The method of the present invention for synthesizing pentafluoropentanol using by-product pentafluorochloroethane has a fast reaction speed, meets the characteristics of green chemistry, and is suitable for industrialization.

(2) The method of the present invention for synthesizing pentafluoropentanol using by-product pentafluorochloroethane provides a new method for treating pentafluorochloroethane.

(3) The pentafluoropentanol synthesized by the method of the present invention has high yield and high purity.

DETAILED DESCRIPTION

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

The raw materials and reagents used in the following examples and comparative examples are all commercially available products, and the devices used are all existing devices.

The by-product pentafluorochloroethane used in the present invention has a content of ≥99%, which is a by-product from the fluorination process of perfluoroethane. The magnesium chips used in the present invention are normal commercial products, and the general conventional size is 2mm×3mm×0.6mm, but it is not limited to this size. As long as it is commercially available magnesium chips, it can meet the requirements. The following embodiments and comparative examples all use the most conventional magnesium chips with a conventional size of 2mm×3mm×0.6mm, and those skilled in the art can clearly distinguish magnesium chips and magnesium powder when they are purchased in the normal market, and there is no confusion. Magnesium chips (2mm×3mm×0.6mm) are used instead of magnesium powder (particle size 0.5mm). After experiments using magnesium powder (other steps are the same as in Example 1), the conversion rate is only 70%, and the yield of pentafluoropentanol is only 30.3%.

Example 1

The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane comprises the following steps:

(1) 4016 g (25.99 mol) of by-product pentafluorochloroethane was added to 3 L of anhydrous tetrahydrofuran to obtain solution A;

(2) A condenser and a dropping funnel were installed on the high pressure reactor, and magnesium chips (31.19 mol) and 1 L of anhydrous tetrahydrofuran solvent were added and mixed to obtain solution B;

(3) At 60°C, add 1/5 volume of solution A to solution B at a rate of 50 mL/min to initiate the reaction, start stirring and reflux to cool down, control the reaction temperature to 50°C, and the reaction time to 10 min;

(4) Add the remaining solution A to solution B at a rate of 30 mL/min, and carry out Grignard reaction at 45°C for 9 h to obtain pentafluoroethane magnesium chloride solution;

(5) Cool the pentafluoroethane magnesium chloride solution to 0°C, add 25.99 mol of oxetane at 1 drop/s, and carry out a ring-opening reaction at 40°C for 3 hours. After the reaction is completed, release the pressure, add 500 g of water to quench, and distill at 65°C to obtain a crude pentafluoropentanol;

(6) The crude pentafluoropentanol is added to a distillation tower for distillation, and the fraction at 62° C.-64° C. is collected to obtain high-purity pentafluoropentanol.

Example 2

The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane comprises the following steps:

(1) 4016 g (25.99 mol) of by-product pentafluorochloroethane was added to 3 L of anhydrous n-hexane to obtain solution A;

(2) Install a condenser and a dropping funnel on the autoclave, add magnesium chips (43.188 mol) and 1 L of anhydrous n-hexane, and mix to obtain solution B;

(3) At 70°C, add 1/5 volume of solution A to solution B at a rate of 50 mL/min to initiate the reaction, start stirring and reflux to cool down, control the reaction temperature to 70°C, and the reaction time to 8 min;

(4) Add the remaining solution A to solution B at a rate of 30 mL/min, and carry out Grignard reaction at 60°C for 12 h to obtain pentafluoroethane magnesium chloride solution;

(5) Cool the pentafluoroethane magnesium chloride solution to 0°C, add oxetane at 1 drop/s, and carry out a ring-opening reaction at 30°C for 4 hours. After the reaction is completed, release the pressure, add 500 g of water to quench, and distill at 60°C to obtain a crude pentafluoropentanol;

(6) The crude pentafluoropentanol is added to a distillation tower for distillation, and the fraction at 62° C.-64° C. is collected to obtain high-purity pentafluoropentanol.

Example 3

The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane comprises the following steps:

(1) 4016 g (25.99 mol) of by-product pentafluorochloroethane was added to 3 L of anhydrous tetrahydrofuran solvent to obtain solution A;

(2) Install a condenser and a dropping funnel on the high pressure reactor, add magnesium chips (35 mol) and 1 L of anhydrous tetrahydrofuran solvent, and mix to obtain solution B;

(3) At 40°C, add 1/3 volume of solution A to solution B at a rate of 50 mL/min to initiate the reaction, start stirring and reflux to cool down, control the reaction temperature to 40°C, and the reaction time to 30 min;

(4) Add the remaining solution A to solution B at a rate of 30 mL/min, and carry out Grignard reaction at 30°C for 12 h to obtain pentafluoroethane magnesium chloride solution;

(5) Cool the pentafluoroethane magnesium chloride solution to 0°C, add 27 mol of oxetane at 1 drop/s, and carry out a ring-opening reaction at 30°C for 4 hours. After the reaction is completed, release the pressure, add 500 g of water to quench, and distill at 70°C to obtain a crude pentafluoropentanol;

(6) The crude pentafluoropentanol is added to a distillation tower for distillation, and the fraction at 62° C.-64° C. is collected to obtain high-purity pentafluoropentanol.

Example 4

The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane comprises the following steps:

(1) 4016 g (25.99 mol) of by-product pentafluorochloroethane was added to 3 L of anhydrous toluene to obtain solution A;

(2) Install a condenser and a dropping funnel on the high-pressure reactor, add magnesium chips (34 mol) and 1 L of anhydrous toluene solvent, and mix to obtain solution B;

(3) At 80°C, add 1/5 volume of solution A to solution B at a rate of 50 mL/min to initiate the reaction, start stirring and reflux to cool down, control the reaction temperature to 60°C, and the reaction time to 5 min;

(4) Add the remaining solution A to solution B at a rate of 30 mL/min, and carry out Grignard reaction at 60°C for 9 h to obtain pentafluoroethane magnesium chloride solution;

(5) Cool the pentafluoroethane magnesium chloride solution to 0°C, add 27 mol of oxetane at 1 drop/s, and carry out a ring-opening reaction at 50°C for 2 h. After the reaction is completed, release the pressure, add 500 g of water to quench, and distill at 65°C to obtain a crude pentafluoropentanol;

(6) The crude pentafluoropentanol is added to a distillation tower for distillation, and the fraction at 62° C.-64° C. is collected to obtain high-purity pentafluoropentanol.

Example 5

The method for synthesizing pentafluoropentanol using by-product pentafluorochloroethane comprises the following steps:

(1) 4016 g (25.99 mol) of by-product pentafluorochloroethane was added to 3 L of anhydrous ether solvent to obtain solution A;

(2) Install a condenser and a dropping funnel on the autoclave, add magnesium chips (31.19 mol) and 1 L of anhydrous ether, and mix to obtain solution B;

(3) At 60°C, add 1/3 volume of solution A to solution B at a rate of 50 mL/min to initiate the reaction, start stirring and reflux to cool down, control the reaction temperature to 50°C, and the reaction time to 10 min;

(4) Add the remaining solution A to solution B at a rate of 30 mL/min, and carry out Grignard reaction at 60°C for 8 h to obtain pentafluoroethane magnesium chloride solution;

(5) Cool the pentafluoroethane magnesium chloride solution to -10°C, add 25.99 mol of oxetane at 1 drop/s, and carry out a ring-opening reaction at 40°C for 3 hours. After the reaction is completed, release the pressure, add 500 g of water to quench, and distill at 70°C to obtain a crude pentafluoropentanol;

(6) The crude pentafluoropentanol is added to a distillation tower for distillation, and the fraction at 62° C.-64° C. is collected to obtain high-purity pentafluoropentanol.

Comparative Example 1

This comparative example is the same as Example 1, except that the solvent in step (1) is replaced by dimethylformamide, and the other preparations are the same.

Comparative Example 2

This comparative example is the same as Example 1, except that the "reaction temperature of 50° C." in step (3) is replaced by "reaction temperature of 20° C.", and the other preparations are the same.

The purity and conversion rate of pentafluoropentanol prepared in the above examples and comparative examples were based on pentafluorochloroethane, conversion rate = actual consumption of pentafluorochloroethane/total amount of pentafluorochloroethane added, the purity result was determined by gas chromatography, and the yield was calculated after distillation, and the test results are shown in Table 1.

Table 1 Test results

As can be seen from Table 1, the synthesis method of the present invention not only makes efficient use of the by-product pentafluorochloroethane, saves the cost of raw materials, has a fast reaction speed, and the synthesized pentafluoropentanol has a high yield and high purity, and has high economic benefits and environmental value.

Claims (8)

1. A method for synthesizing pentafluoropentanol by utilizing byproduct pentafluoroethane is characterized in that: the method comprises the following steps:

(1) Adding byproduct pentafluoroethane into a solvent to obtain a solution A;

(2) Adding magnesium chips into a solvent to obtain a solution B;

The solvent in the step (1) and the solvent in the step (2) are both one of ether solvents or hydrocarbon solvents; the ether solvent is tetrahydrofuran or diethyl ether, and the hydrocarbon solvent is one of benzene, toluene, n-hexane and cyclohexane;

(3) Adding 1/5-1/3 volume of the solution A into the solution B at the temperature of 40-80 ℃ to initiate the reaction;

(4) Adding the residual solution A into the solution B, and carrying out Grignard reaction to obtain pentafluoroethane magnesium chloride solution;

(5) Cooling pentafluoroethane magnesium chloride solution to-10-0 ℃, adding oxetane, carrying out ring-opening reaction, and processing after the reaction is finished to obtain a coarse product of pentafluoroethyl alcohol;

(6) And rectifying the crude product of the pentafluoropentanol to obtain the pentafluoropentanol.

2. The method for synthesizing pentafluoropentanol by using by-produced pentafluoroethane as claimed in claim 1, wherein: the molar ratio of the byproduct pentafluoroethane to magnesium turnings is 1:1-2.

3. The method for synthesizing pentafluoropentanol by using by-produced pentafluoroethane as claimed in claim 1, wherein: the theoretical yield of pentafluoroethane magnesium chloride and the mol ratio of oxetane are 1:1-1.2.

4. The method for synthesizing pentafluoropentanol by using by-produced pentafluoroethane as claimed in claim 1, wherein: the Grignard reaction temperature in the step (4) is 30-60 ℃ and the reaction time is 8-12 h.

5. The method for synthesizing pentafluoropentanol by using by-produced pentafluoroethane as claimed in claim 1, wherein: the processing steps of the step (5) are as follows: and (3) decompressing the solution after the reaction is finished, adding water for quenching, and distilling.

6. The method for synthesizing pentafluoropentanol using by-produced pentafluoroethane as claimed in claim 5, wherein: the distillation temperature is 60-70 ℃.

7. The method for synthesizing pentafluoropentanol by using by-produced pentafluoroethane as claimed in claim 1, wherein: the temperature of the ring-opening reaction in the step (5) is 30-50 ℃ and the reaction time is 2-4 h.

8. The method for synthesizing pentafluoropentanol by using by-produced pentafluoroethane as claimed in claim 1, wherein: and (6) rectifying and collecting fractions at 62-64 ℃.