CN111825528A - Method for purifying fluorine-containing alcohol - Google Patents
Method for purifying fluorine-containing alcohol Download PDFInfo
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- CN111825528A CN111825528A CN202010543117.XA CN202010543117A CN111825528A CN 111825528 A CN111825528 A CN 111825528A CN 202010543117 A CN202010543117 A CN 202010543117A CN 111825528 A CN111825528 A CN 111825528A
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- C07—ORGANIC CHEMISTRY
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- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
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- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
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Abstract
In order to overcome the problem that the purity of the fluorine-containing alcohol purified by the existing fluorine-containing alcohol purification method is insufficient, the invention provides a fluorine-containing alcohol purification method, which comprises the following operation steps: carrying out primary rectification operation on a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol and water serving as a raw material mixture to rectify, extract and separate a fluorine-containing alcohol primary product, collecting fractions of the fluorine-containing alcohol primary product, and obtaining a non-fluorine-containing alcohol/water mixture at the bottom of a tower after the fluorine-containing alcohol primary product is separated from the raw material mixture; continuing to perform secondary rectification operation on the non-fluorine-containing alcohol/water mixture to enable the non-fluorine-containing alcohol to be rectified, extracted and separated, collecting the fraction of the non-fluorine-containing alcohol, and obtaining water at the bottom of the tower after the non-fluorine-containing alcohol/water mixture is separated from the non-fluorine-containing alcohol; and continuously recycling the water after the non-fluorine-containing alcohol is separated as the water in the raw material mixture. The method for purifying the fluorine-containing alcohol has the advantages of good separation degree, simple operation, low cost and easy industrialization.
Description
Technical Field
The invention belongs to the technical field of purification of a fluorine-containing alcohol chemical product, and particularly relates to a purification method of fluorine-containing alcohol.
Background
The fluorine-containing alcohol is not flammable, has small surface tension and can clean small parts; the cleaning agent has good cleaning effect on polyethylene glycol, ester oil and water-soluble flux, can be used as a cleaning agent and a solvent, and in addition, the fluorine-containing alcohol is an important fluorine-containing fine chemical and has wide application in the fields of pesticide, medicine, fluoropolymer synthesis and the like.
The synthesis of the fluorine-containing alcohol mainly comprises an addition method, a catalytic hydrogenation method, a catalytic oxidation method and the like, the non-fluorine-containing alcohol is usually used as a solvent in the reaction process or the existing fluorine-containing alcohol which generates a non-fluorine-containing alcohol byproduct is inevitably introduced into the non-fluorine-containing alcohol in the preparation process in the form of a synthetic raw material or a reaction solvent, in the final product of the reaction, the purity of the fluorine-containing alcohol is affected by the existence of the non-fluorine-containing alcohol, so that some performances of the fluorine-containing alcohol as a surfactant or other processing reagents are affected, purification is required to be carried out in the crude product of the fluorine-containing alcohol, the non-fluorine-containing alcohol is removed to obtain the fluorine-containing alcohol with higher purity, the existing purification mode is mainly realized by a common rectification mode, however, there are some fluorine-containing alcohol products in which a small amount of non-fluorine-containing alcohol is mixed and which have a boiling point close to that of the fluorine-containing alcohol, or forms an azeotrope with the fluorine-containing alcohol, and a small amount of non-fluorine-containing alcohol mixed in the fluorine-containing alcohol product is difficult to further separate by ordinary rectification.
Disclosure of Invention
Aiming at the problem that the purity of the fluorine-containing alcohol purified by the existing fluorine-containing alcohol purification method is insufficient, the invention provides a fluorine-containing alcohol purification method.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the invention provides a method for purifying fluorine-containing alcohol, which comprises the following operation steps:
carrying out primary rectification operation on a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol and water serving as a raw material mixture to rectify, extract and separate a fluorine-containing alcohol primary product, collecting fractions of the fluorine-containing alcohol primary product, and separating the fluorine-containing alcohol primary product from the raw material mixture to obtain a non-fluorine-containing alcohol/water mixture;
continuing to perform secondary rectification operation on the non-fluorine-containing alcohol/water mixture to separate the non-fluorine-containing alcohol by rectification, collecting the fraction of the non-fluorine-containing alcohol, and separating the non-fluorine-containing alcohol from the non-fluorine-containing alcohol/water mixture to obtain water;
and recycling the water after the non-fluorine-containing alcohol is separated as the water in the raw material mixture.
Optionally, the primary rectification operation is performed in a first rectification tower, water is added from the upper part of the first rectification tower, a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is added from the lower part of the first rectification tower, a fraction of the fluorine-containing alcohol primary product is extracted from the top of the tower, and the non-fluorine-containing alcohol/water mixture is extracted from the bottom of the tower; the secondary rectification operation is carried out in a second rectification tower, the fraction containing no fluorine alcohol is extracted from the top of the tower, and the water after separating the non-fluorine alcohol is led out from the bottom of the tower.
Optionally, the operating pressure of the first rectifying tower is-0.05-0.2 MPa, the reflux ratio is 1-20, and the number of theoretical plates is 20-90;
the operating pressure of the second rectifying tower is-0.05-0.2 MPa, the reflux ratio is 0.5-30, and the number of theoretical plates is 10-60.
Optionally, drying and dehydrating the obtained initial product containing the fluorine alcohol by adopting a drying agent to obtain a product containing the fluorine alcohol.
Optionally, the drying agent includes one or more of a molecular sieve drying agent, anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride, concentrated sulfuric acid, fuming sulfuric acid, and phosphorus pentoxide.
Optionally, the fluorine-containing alcohol comprises one or more of 2,2, 2-trifluoroethanol, 2, 2-difluoroethanol, 2-chloro-2, 2-difluoroethanol, 2,2,3,3,3, 3-pentafluoropropanol, 1,1,1,3,3, 3-hexafluoro-2-propanol, 1,1, 1-trifluoro-2-methyl-2-propanol, 2,2,3,3,4,4, 4-heptafluoro-1-butanol, perfluoro-tert-butanol, and 2, 2-bis (trifluoromethyl) propanol.
Optionally, the non-fluorine containing alcohol comprises one or more of methanol, ethanol, n-propanol, isopropanol and tert-butanol.
Optionally, the non-fluoroalcohol containing fluoroalcohol mixture does not contain water.
Optionally, the fluorine-containing alcohol mixture containing the non-fluorine-containing alcohol further contains water.
Optionally, the mass ratio of the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol to water is 1: 3 to 15.
According to the method for purifying the fluorine-containing alcohol, water is used as an additive of a fluorine-containing alcohol mixture containing the non-fluorine-containing alcohol, the affinity between the non-fluorine-containing alcohol and the water is high, the affinity between the fluorine-containing alcohol and the water is low, the relative volatility of the fluorine-containing alcohol and the non-fluorine-containing alcohol is improved by utilizing the existence of the water, the rectification separation efficiency is improved, a high-purity fluorine-containing alcohol initial product is obtained, a good technical effect is obtained, and the method can be used for industrial production for continuously separating the fluorine-containing alcohol and the non-fluorine-containing alcohol. The technical scheme of the invention has the advantages of good separation degree, simple operation, low cost and easy industrialization.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
An embodiment of the present invention provides a method for purifying a fluorinated alcohol, including the following steps:
carrying out primary rectification operation on a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol and water serving as a raw material mixture to rectify, extract and separate a fluorine-containing alcohol primary product, collecting fractions of the fluorine-containing alcohol primary product, and separating the fluorine-containing alcohol primary product from the raw material mixture to obtain a non-fluorine-containing alcohol/water mixture;
continuing to perform secondary rectification operation on the non-fluorine-containing alcohol/water mixture to separate the non-fluorine-containing alcohol by rectification, collecting the fraction of the non-fluorine-containing alcohol, and separating the non-fluorine-containing alcohol from the non-fluorine-containing alcohol/water mixture to obtain water;
and recycling the water after the non-fluorine-containing alcohol is separated as the water in the raw material mixture.
The method adopts water as the additive of the fluorine-containing alcohol mixture containing the non-fluorine-containing alcohol, because the affinity of the non-fluorine-containing alcohol and the water is higher, and the affinity of the fluorine-containing alcohol and the water is lower, the relative volatility of the fluorine-containing alcohol and the non-fluorine-containing alcohol is improved by utilizing the existence of the water, the rectification separation efficiency is improved to obtain a high-purity fluorine-containing alcohol initial product, the content of the non-fluorine-containing alcohol can be controlled below 1w percent, better technical effect is obtained, and the method can be used in the industrial production for continuously separating the fluorine-containing alcohol and the non-fluorine-containing alcohol. The technical scheme of the invention has the advantages of good separation degree, simple operation, low cost and easy industrialization.
Wherein, the water is separated in the subsequent secondary rectification operation, the water content in the obtained water after the non-fluorine-containing alcohol is separated can be controlled to be more than 99.95wt percent, and the high-temperature water obtained in the secondary rectification operation is added into the primary rectification operation again to be used as a raw material mixture, so that the water required to be consumed in the primary rectification operation and the heat energy consumed by heating can be effectively reduced.
In some embodiments, the primary rectification operation is performed in a first rectification column, water is fed from the upper part of the first rectification column, a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is fed from the lower part of the first rectification column, a fraction of the fluorine-containing alcohol primary product is withdrawn from the top of the column, and the non-fluorine-containing alcohol/water mixture is withdrawn from the bottom of the column; the secondary rectification operation is carried out in a second rectification tower, the fraction containing no fluorine alcohol is extracted from the top of the tower, and the water after separating the non-fluorine alcohol is led out from the bottom of the tower.
The first rectification column and the second rectification column may each independently be selected from a tray column including a bubble cap column, a sieve plate column and a float valve column, or a packed column, in a preferred embodiment, the tray column is selected from a sieve plate column, the packing in the packed column includes loose packing and structured packing, and in a preferred embodiment, the packing in the packed column is selected from wire mesh structured packing.
The non-fluorine-containing alcohol extracted from the top of the second rectifying tower can be further used industrially or incinerated.
In some embodiments of the present invention, the,
the water after separating the non-fluorine-containing alcohol is guided out by the second rectifying tower and then needs to be subjected to heat preservation treatment, specifically, the water in the tower kettle of the second rectifying tower is guided into the first rectifying tower through a pipeline and a pump, a heat preservation layer is arranged outside the pipeline, the temperature of the water is kept, and the material temperature fluctuation in the first rectifying tower caused by the over-low temperature of the water is avoided.
Specifically, the fluorine-containing alcohol mixture containing the non-fluorine-containing alcohol is fed to the first rectifying column after being preheated to a bubble point, so as to avoid material temperature fluctuation.
In some embodiments, the first rectification column is operated at a pressure of-0.05 to 0.2MPa, a reflux ratio of 1 to 20, and a theoretical plate number of 20 to 90;
the operating pressure of the second rectifying tower is-0.05-0.2 MPa, the reflux ratio is 0.5-30, and the number of theoretical plates is 10-60.
In some embodiments, the obtained initial product containing fluorine alcohol is dried and dewatered by a drying agent to obtain the product containing fluorine alcohol.
The primary product of the fluorine-containing alcohol after being rectified by the first rectifying tower contains certain moisture, and the residual moisture in the primary product of the fluorine-containing alcohol can be removed in a manner of adding a drying agent, so that the purity of the fluorine-containing alcohol product is improved.
In some embodiments, the desiccant comprises one or more of a molecular sieve desiccant, anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride, concentrated sulfuric acid, oleum, phosphorus pentoxide.
In some embodiments, the fluorine-containing alcohol comprises one or more of 2,2, 2-trifluoroethanol, 2,2, -difluoroethanol, 2-chloro-2, 2-difluoroethanol, 2,2,3,3,3, 3-pentafluoropropanol, 1,1,1,3,3, 3-hexafluoro-2-propanol, 1,1, 1-trifluoro-2-methyl-2-propanol, 2,2,3,3,4,4, 4-heptafluoro-1-butanol, perfluoro-tert-butanol, and 2, 2-bis (trifluoromethyl) propanol.
In some embodiments, the non-fluorine containing alcohol comprises one or more of methanol, ethanol, n-propanol, isopropanol, and tert-butanol.
It should be noted that the above are merely some specific examples of the present invention, and do not represent limitations of the present invention.
In some embodiments, the non-fluoroalcohol containing fluoroalcohol mixture does not contain additional water.
In some embodiments, the non-fluoroalcohol containing fluoroalcohol mixture further comprises water.
In some embodiments, the mass ratio of the fluorine-containing alcohol mixture containing a non-fluorine-containing alcohol to water is 1: 3 to 15.
The fluorine-containing alcohol mixture containing the non-fluorine-containing alcohol and the water are continuously fed into the first rectification column in the primary rectification operation, and the material ratio is controlled by controlling the flow rate of the fluorine-containing alcohol mixture containing the non-fluorine-containing alcohol and the water.
The present invention will be further illustrated by the following examples.
Example 1
The embodiment of the invention discloses a method for purifying fluorine-containing alcohol, which comprises the following operation steps:
the first rectifying column bottom 200L has 35 theoretical plates (the number of plates is from top to bottom), water (ethanol is less than 0.1 wt%) extracted from the second rectifying column bottom is added from the 15 th theoretical plate, the flow rate is 120.0kg/h, a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol comprises a mixture of pentafluoropropanol, ethanol and water, the water is added from the 25 th plate, wherein the content of the pentafluoropropanol is 65 wt%, the content of the ethanol is 30 wt%, the content of the water is 5 wt%, the total flow rate is 15.0kg/h, and the mass ratio of the water to the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is 8: 1. the first rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 5, the extraction amount of the initial product of the fluorine-containing alcohol at the top of the first rectifying tower is 10.1kg/h, and the composition of the initial product is 94.08 wt% of pentafluoropropanol, 0.12 wt% of ethanol and 5.80 wt% of water. The first rectifying tower consists of 0.18 wt% of pentafluoropropanol, 3.81 wt% of ethanol and 96.01 wt% of water. The tower top temperature of the first rectifying tower is 78 ℃, and the tower kettle temperature is 96 ℃. The product in the first rectifying tower kettle is conveyed to the 10 th theoretical plate of the second rectifying tower through a pump to be added, the flow rate is 125.0kg/h, and 200L of the second rectifying tower kettle is provided with 20 theoretical plates (the number of the plates is from top to bottom). The second rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 8, the extraction amount at the top of the tower is 5.1kg/h, and 4.1 wt% of pentafluoropropanol, 88.3 wt% of ethanol and 7.6 wt% of water can be obtained. The tower top temperature of the second rectifying tower is 78 ℃, and the tower kettle temperature is 100 ℃. The water replenishing speed is 0.22 kg/h.
Example 2
The embodiment of the invention discloses a method for purifying fluorine-containing alcohol, which comprises the following operation steps:
the 200L of the first rectifying tower still has 35 theoretical plates (the number of the plates is counted from top to bottom), water (ethanol is less than 0.1 wt%) extracted from the second rectifying tower still is added from the 15 th theoretical plate, the flow rate is 90.0kg/h, the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol comprises a mixture of pentafluoropropanol, ethanol and water, the water is added from the 25 th plate, wherein the content of the pentafluoropropanol is 65 wt%, the content of the ethanol is 30 wt%, the content of the water is 5 wt%, the total flow rate is 15.0kg/h, and the mass ratio of the water to the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is 8: 1. the first rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 5, the extraction amount of the primary product of the fluorine-containing alcohol at the top of the first rectifying tower is 10.2kg/h, and the composition of the primary product is 93.32 wt% of pentafluoropropanol, 0.97 wt% of ethanol and 5.71 wt% of water. The first rectifying tower consists of 0.14 wt% of pentafluoropropanol, 2.97 wt% of ethanol and 96.89 wt% of water. The tower top temperature of the first rectifying tower is 78 ℃, and the tower bottom temperature is 97 ℃. The product in the first rectifying tower is pumped to the 10 th theoretical plate of the second rectifying tower at the flow rate of 92.88kg/h, and the second rectifying tower has 20 theoretical plates (the number of plates is from top to bottom) in 200L. The second rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 8, the extraction amount at the top of the tower is 5.0kg/h, and 4.2 wt% of pentafluoropropanol, 87.7 wt% of ethanol and 8.1 wt% of water can be obtained. The tower top temperature of the second rectifying tower is 79 ℃, and the tower kettle temperature is 100 ℃. The water replenishing speed is 0.2 kg/h.
Example 3
The embodiment of the invention discloses a method for purifying fluorine-containing alcohol, which comprises the following operation steps:
the first rectifying tower bottom 200L has 35 theoretical plates (the number of the plates is from top to bottom), water (ethanol is less than 0.1 wt%) extracted from the second rectifying tower bottom is added from the 15 th theoretical plate, the flow rate is 120.0kg/h, a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol comprises a mixture of pentafluoropropanol, ethanol and water, the fluorine-containing alcohol mixture is added from the 25 th plate, wherein the content of the pentafluoropropanol is 65 wt%, the content of the ethanol is 30 wt%, the content of the water is 5 wt%, the total flow rate is 15.0kg/h, and the mass ratio of the water to the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is 8: 1. the first rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 3, the extraction amount of the primary product of the fluorine-containing alcohol at the top of the first rectifying tower is 10.2kg/h, and the composition of the primary product of the fluorine-containing alcohol is 91.98 wt% of pentafluoropropanol, 0.61 wt% of ethanol and 7.41 wt% of water. The first rectifying tower consists of 0.49 wt% of pentafluoropropanol, 6.42 wt% of ethanol and 93.09 wt% of water. The tower top temperature of the first rectifying tower is 78 ℃, and the tower bottom temperature is 84 ℃. The product in the first rectifying tower is conveyed to the 10 th theoretical plate of the second rectifying tower by a pump, the flow rate is 128.8kg/h, and 200L of the second rectifying tower has 20 theoretical plates (the number of the plates is from top to bottom). The second rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 8, the extraction amount at the top of the tower is 5.0kg/h, and 6.7 wt% of pentafluoropropanol, 87.4 wt% of ethanol and 5.9 wt% of water can be obtained. The tower top temperature of the second rectifying tower is 78 ℃, and the tower kettle temperature is 100 ℃. The water replenishing speed is 0.3 kg/h.
Example 4
The embodiment of the invention discloses a method for purifying fluorine-containing alcohol, which comprises the following operation steps:
the 200L of the first rectifying tower bottom is provided with 26 theoretical plates (the plate number is counted from top to bottom), water (ethanol is less than 0.1 wt%) extracted from the second rectifying tower bottom is added from the 10 th theoretical plate, the flow rate is 120.0kg/h, the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol comprises a mixture of pentafluoropropanol, ethanol and water, the pentafluoropropanol is added from the 16 th plate, the content of the pentafluoropropanol is 65 wt%, the ethanol is 30 wt%, the water is 5 wt%, the total flow rate is 15.0kg/h, and the mass ratio of the water to the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is 8: 1. the first rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 5, the extraction amount of the initial product of the fluorine-containing alcohol at the top of the first rectifying tower is 10.3kg/h, and the initial product of the fluorine-containing alcohol consists of pentafluoropropanol 92.73 wt%, ethanol 0.47 wt% and water 6.80 wt%. The first rectifying tower still consists of 0.26 wt% of pentafluoropropanol, 5.43 wt% of ethanol and 94.31 wt% of water. The tower top temperature of the first rectifying tower is 78 ℃, and the tower bottom temperature is 94 ℃. The product in the first rectifying tower is pumped to the 10 th theoretical plate of the second rectifying tower at a flow rate of 127.2kg/h, and the second rectifying tower has 20 theoretical plates (the number of the plates is from top to bottom) in 200L. The second rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 8, the extraction amount at the top of the tower is 5.0kg/h, and 4.2 wt% of pentafluoropropanol, 88.9 wt% of ethanol and 6.9 wt% of water can be obtained. The tower top temperature of the second rectifying tower is 78 ℃, and the tower kettle temperature is 100 ℃. The water replenishing speed is 0.3 kg/h.
Example 5
The embodiment of the invention discloses a method for purifying fluorine-containing alcohol, which comprises the following operation steps:
the 200L of the first rectifying tower bottom is provided with 35 theoretical plates (the plate number is counted from top to bottom), water (ethanol is less than 0.1 wt%) extracted from the second rectifying tower bottom is added from the 15 th theoretical plate, the flow rate is 120.0kg/h, the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol comprises a mixture of trifluoroethanol, ethanol and water, the fluorine-containing alcohol mixture is added from the 25 th plate, wherein the trifluoroethanol content is 75 wt%, the ethanol content is 20 wt%, the water content is 5 wt%, the total flow rate is 15.0kg/h, and the mass ratio of the water to the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is 8: 1. the first rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 5, the extraction amount of the fluorine-containing alcohol primary product at the top of the first rectifying tower is 11.4kg/h, and the components of the fluorine-containing alcohol primary product are 98.122 wt% of trifluoroethanol, 0.008 wt% of ethanol and 1.870 wt% of water. The first rectifying tower consists of 0.01 wt% of trifluoroethanol, 2.01 wt% of ethanol and 97.98 wt% of water. The tower top temperature of the first rectifying tower is 58 ℃, and the tower kettle temperature is 99 ℃. The product in the first rectifying tower is conveyed to the 10 th theoretical plate of the second rectifying tower by a pump, the flow rate is 122.5kg/h, and 200L of the second rectifying tower kettle is provided with 20 theoretical plates (the number of the plates is from top to bottom). The second rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 10, the yield of the top of the tower is 3.3kg/h, and 0.67 wt% of trifluoroethanol, 91.47 wt% of ethanol and 7.86 wt% of water can be obtained. The tower top temperature of the second rectifying tower is 80 ℃, and the tower kettle temperature is 100 ℃. The water withdrawal speed was 0.3 kg/h.
Example 6
The embodiment of the invention discloses a method for purifying fluorine-containing alcohol, which comprises the following operation steps:
the 200L of the first rectifying tower bottom is provided with 35 theoretical plates (the plate number is counted from top to bottom), water (ethanol is less than 0.1 wt%) extracted from the second rectifying tower bottom is added from the 15 th theoretical plate, the flow rate is 120.0kg/h, a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol comprises a mixture of hexafluoroisopropanol, methanol and water, the hexafluoroisopropanol content is 65 wt%, the methanol content is 20 wt%, the water content is 15 wt%, the total flow rate is 15.0kg/h, and the mass ratio of the water to the fluorine-containing alcohol mixture containing non-fluorine-containing alcohol is 8: 1. the first rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 5, the extraction amount of the initial product of the fluorine-containing alcohol at the top of the first rectifying tower is 9.9kg/h, and the composition of the initial product is 97.895 wt% of hexafluoroisopropanol, 0.004 wt% of methanol and 2.101 wt% of water. The first rectifying tower consists of hexafluoroisopropanol 0.02 wt%, methanol 2.85 wt% and water 97.13 wt%. The tower top temperature of the first rectifying tower is 58 ℃, and the tower bottom temperature is 98 ℃. The product in the first rectifying tower is conveyed to the 10 th theoretical plate of the second rectifying tower by a pump, the flow rate is 123.5kg/h, and 200L of the second rectifying tower has 20 theoretical plates (the number of the plates is from top to bottom). The second rectifying tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 15, the extraction amount at the top of the tower is 3.1kg/h, and 0.8 wt% of hexafluoroisopropanol, 97.9 wt% of methanol and 1.3 wt% of water can be obtained. The tower top temperature of the second rectifying tower is 65 ℃, and the tower kettle temperature is 100 ℃. The water withdrawal speed was 2.0 kg/h.
Comparative example 1
This comparative example is used to illustrate a purification process for a fluorinated alcohol disclosed herein, comprising the following steps:
the first rectifying tower has 50 theoretical plates in 200L, and the first rectifying tower has one mixture of pentafluoropropanol, ethanol and water in 150kg in 65 wt%, ethanol in 30 wt% and water in 5 wt% fed into the tower, and has material composition of 94.85 wt% ethanol, 0.43 wt% pentafluoropropanol and 4.72 wt% water extracted in intermittent rectification at reflux ratio of 10. With the increase of extracted materials, the content of ethanol is reduced, the content of pentafluoropropanol is increased, and then a fraction rich in pentafluoropropanol can be extracted, wherein the content of pentafluoropropanol is 93.74 wt%, the content of ethanol is 1.52 wt%, and the content of water is 4.74 wt%, so that a total of 150kg of primary purified products rich in pentafluoropropanol are obtained by rectifying a plurality of batches, wherein the content of pentafluoropropanol is 93.62 wt%, the content of ethanol is 1.59 wt%, and the content of water is 4.79 wt%, and the mixture is returned to a kettle of a 200L second rectifying tower, the second rectifying tower has 50 theoretical plates, or is intermittent, firstly, a full reflux manner is adopted for stabilizing reflux for 8 hours to ensure that the rectifying tower is fully balanced, and then a sampling composition of the secondary purified products at the top of the tower is as follows: the content of the pentafluoropropanol is 93.48 wt%, the content of the ethanol is 1.87 wt%, the content of the water is 4.65 wt%, and a sampling composition at a tower kettle comprises: the content of pentafluoropropanol was 93.63 wt%, the content of ethanol was 1.59 wt%, and the content of water was 4.79 wt%.
Comparison of results
The results of the primary fluorine-containing alcohol products prepared in examples 1 to 6 and the primary purified product and the secondary purified product prepared in comparative example 1 are shown in Table 1.
TABLE 1
As can be seen from the test results in table 1, the initial product of the fluorine-containing alcohol obtained by the method for purifying fluorine-containing alcohol provided by the present invention can effectively reduce the content of non-fluorine-containing alcohol to 1%, specifically, the non-fluorine-containing alcohol can be controlled to 0.004% in the preferred embodiment, which is beneficial for the preparation of high purity fluorine-containing alcohol, while the content of ethanol in the primary purified product obtained by the comparative example 1 using batch distillation is still 1.59 wt%, and the composition of the secondary purified product obtained by the secondary distillation is similar to that of the primary purified product, which indicates that the composition is close to the component of the azeotrope, and the small amount of ethanol remained in pentafluoropropanol is difficult to be separated by the conventional method.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A method for purifying a fluorine-containing alcohol, comprising the following steps:
carrying out primary rectification operation on a fluorine-containing alcohol mixture containing non-fluorine-containing alcohol and water serving as a raw material mixture to rectify, extract and separate a fluorine-containing alcohol primary product, collecting fractions of the fluorine-containing alcohol primary product, and separating the fluorine-containing alcohol primary product from the raw material mixture to obtain a non-fluorine-containing alcohol/water mixture;
continuing to perform secondary rectification operation on the non-fluorine-containing alcohol/water mixture to separate the non-fluorine-containing alcohol by rectification, collecting the fraction of the non-fluorine-containing alcohol, and separating the non-fluorine-containing alcohol from the non-fluorine-containing alcohol/water mixture to obtain water;
and recycling the water after the non-fluorine-containing alcohol is separated as the water in the raw material mixture.
2. The method for purifying a fluorine-containing alcohol according to claim 1, wherein the primary distillation operation is carried out in a first distillation column, water is fed from an upper part of the first distillation column, a fluorine-containing alcohol mixture containing a non-fluorine-containing alcohol is fed from a lower part of the first distillation column, a fraction of the fluorine-containing alcohol primary product is taken out from the top of the column, and the non-fluorine-containing alcohol/water mixture is taken out from the bottom of the column; the secondary rectification operation is carried out in a second rectification tower, the fraction containing no fluorine alcohol is extracted from the top of the tower, and the water after separating the non-fluorine alcohol is led out from the bottom of the tower.
3. The method for purifying a fluoroalcohol according to claim 2, wherein the first rectifying column is operated at an operating pressure of-0.05 to 0.2MPa, a reflux ratio of 1 to 20, and a theoretical plate number of 20 to 90;
the operating pressure of the second rectifying tower is-0.05-0.2 MPa, the reflux ratio is 0.5-30, and the number of theoretical plates is 10-60.
4. The method for purifying a fluoroalcohol according to claim 1, wherein the obtained fluoroalcohol crude product is dried with a drying agent to remove water, thereby obtaining the fluoroalcohol product.
5. The method of claim 4, wherein the drying agent comprises one or more of a molecular sieve drying agent, anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride, concentrated sulfuric acid, fuming sulfuric acid, and phosphorus pentoxide.
6. The method for purifying a fluorinated alcohol according to claim 1, wherein the fluorinated alcohol comprises one or more of 2,2, 2-trifluoroethanol, 2, 2-difluoroethanol, 2-chloro-2, 2-difluoroethanol, 2,2,3,3,3, 3-pentafluoropropanol, 1,1,1,3,3, 3-hexafluoro-2-propanol, 1,1, 1-trifluoro-2-methyl-2-propanol, 2,2,3,3,4,4, 4-heptafluoro-1-butanol, perfluoro-tert-butanol and 2, 2-bis (trifluoromethyl) propanol.
7. The method of purifying a fluoroalcohol according to claim 1 wherein the non-fluoroalcohol comprises one or more of methanol, ethanol, n-propanol, isopropanol and tert-butanol.
8. The method of purifying a fluorinated alcohol according to claim 1, wherein the mixture of fluorinated alcohols containing a non-fluorinated alcohol does not contain water.
9. The method for purifying a fluorinated alcohol according to claim 1, wherein the mixture of the fluorinated alcohols containing the non-fluorinated alcohol further contains water.
10. The method for purifying a fluorinated alcohol according to claim 1, wherein the mass ratio of the fluorinated alcohol mixture containing a non-fluorinated alcohol to water is 1: 3 to 15.
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| CN1266836A (en) * | 1999-03-15 | 2000-09-20 | 大金工业株式会社 | Process for producing fluoroalcohol |
| CN1370138A (en) * | 1999-08-20 | 2002-09-18 | 旭硝子株式会社 | Process for purification of fluorinated hydroxyl compounds |
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| CN1449366A (en) * | 2000-08-24 | 2003-10-15 | 旭硝子株式会社 | Process for producing a fluorinated alcohol |
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| CN103694082A (en) * | 2013-11-26 | 2014-04-02 | 浙江巨圣氟化学有限公司 | Method for purifying tetrafluoro propanol |
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| CN1266836A (en) * | 1999-03-15 | 2000-09-20 | 大金工业株式会社 | Process for producing fluoroalcohol |
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