CN115894168B - Perfluoroalkyl ethanol and preparation method thereof - Google Patents

Abstract

The invention provides perfluoroalkyl ethanol and a preparation method thereof, and relates to the technical field of fluorine-containing compound synthesis. The method comprises the following steps: firstly, reacting fluorine-containing olefin with concentrated sulfuric acid under the atmosphere of nitrogen to obtain an addition product; then adding the addition product into a high-pressure reaction kettle with magnetic stirring, slowly adding water for hydrolysis reaction, standing, layering, taking the lower transparent solution, washing with water, and drying to obtain the perfluoroalkyl alcohol. The invention firstly utilizes sulfuric acid to carry out addition reaction with fluorine-containing olefin, and then carries out hydrolysis reaction on the obtained addition product, thus obtaining the perfluoroalkyl alcohol. The method can well control the reaction process, greatly shortens the reaction time, has stable yield of the perfluoroalkyl ethanol, and is suitable for industrialized mass production.

Description

A kind of perfluoroalkylethanol and preparation method thereof

Technical Field

The invention relates to the technical field of fluorine-containing compound synthesis, and in particular to a perfluoroalkylethanol and a preparation method thereof.

Background Art

Perfluoroalkylethanol is a type of alcohol in which fluorine atoms replace hydrogen atoms on carbon-hydrogen bonds. Due to the introduction of fluorine atoms, perfluoroalkylethanol exhibits superior properties, making it an important class of aliphatic fluorinated intermediates. Fluorinated alkylethanol has a wide range of uses, mainly in the fields of pesticides, pharmaceutical synthesis, dye synthesis, organic synthesis, materials, fluorinated surfactants, fluorinated emulsifiers and fluorinated ether preparation.

The existing preparation methods of perfluoroalkylethanol include hydrogenation reduction method, oxidation method, hydrolysis method and polymerization method. Among them, for the hydrogenation reduction method, the route of synthesizing trifluoroethanol is currently studied more. The advantage of the gas phase method is that the reaction rate is fast, the gaseous reactants can fully contact with the catalyst, and the contact time is generally less than 1min, the reaction temperature is 100-200°C, and continuous production can be achieved. The liquid phase hydrogenation reduction route is often used to synthesize perfluoroalkylethanol such as trifluoroethanol and hexafluoroisopropanol with high yield. The advantage of the liquid phase method is that the reaction temperature is low, which avoids the depth of side reactions. The amount of hydrogen and other substances is added, and the reaction time is extended to make it fully react. The oxidation method for synthesizing perfluoroalkylethanol generally uses ozone, air, oxygen or a mixture of oxygen and nitrogen as an oxidant. The hydrolysis method is to prepare perfluoroalkylethanol by first esterifying the fluorine-containing hydrocarbon and then hydrolyzing it. Among them, the esterification process and the hydrolysis process can be carried out step by step or in one step. However, the esterification process of the two-step method is easily affected by moisture, and anhydrous solvents must be used, otherwise the moisture in the solvent will increase the by-products, slow down the reaction rate, and even cause the reaction to fail. The one-step method generally does not use organic solvents, but directly uses water as a solvent in the presence of a specific catalyst. Although this method shortens the reaction time and reduces the amount of catalyst, the reaction pressure is too high, which increases the requirements for the reaction equipment. The telomerization method is a free radical polymerization reaction initiated by light, heat or peroxide at a certain temperature and pressure. Using the telomerization reaction, some simple olefin compounds and telomerization agents can be formed into a series of low molecular weight polymers in the presence of an initiator. The telomerization method is increasingly widely used in the synthesis of perfluoroalkylethanol and is a synthetic route with industrial prospects. However, the reaction time for preparing perfluoroalkylethanol using the telomerization method is long and the yield is unstable, and the process control is difficult.

Summary of the invention

The object of the present invention is to provide a perfluoroalkyl ethanol and a preparation method thereof. First, concentrated sulfuric acid is used to carry out an addition reaction with a fluorine-containing olefin, and then a hydrolysis reaction is carried out to obtain the perfluoroalkyl ethanol. The method can not only well control the reaction process and greatly shorten the reaction time, but also has a stable yield of the perfluoroalkyl ethanol, and is suitable for industrial large-scale production.

The present invention solves the technical problem by adopting the following technical solutions.

The present invention provides a method for preparing perfluoroalkylethanol, comprising the following steps:

S1, fluorinated olefin and concentrated sulfuric acid react under a nitrogen atmosphere to obtain an addition product;

S2. After adding the addition product into a high-pressure reactor with magnetic stirring, slowly adding water to carry out a hydrolysis reaction. After standing and stratification, taking the lower layer of transparent solution, washing with water, and drying, to obtain perfluoroalkylethanol.

Furthermore, the fluorine-containing olefin is CF ₃ (CF ₂ ) _n CH＝CH ₂ , wherein n is one of 3, 5, 7 and 9.

Furthermore, the mass percentage of the concentrated sulfuric acid is 96-99%.

Furthermore, the molar ratio of the fluorine-containing olefin to the concentrated sulfuric acid is 1:1-2.

Furthermore, the reaction temperature is 80-160° C., and the reaction time is 12-24 hours.

Furthermore, the volume ratio of the water to the fluorine-containing olefin is 0.1 to 1:1.

Furthermore, the temperature of the hydrolysis reaction is 160-180° C., and the reaction time is 12-18 hours.

Furthermore, the drying step specifically includes: the lower transparent solution is washed with water, and then anhydrous magnesium sulfate is added to absorb water and dry to obtain perfluoroalkylethanol.

The present invention provides a perfluoroalkylethanol, which is prepared according to the preparation method, and the chemical structure of the perfluoroalkylethanol is as follows:

Here, n is one of 3, 5, 7, and 9.

The beneficial effects of the perfluoroalkylethanol and the preparation method thereof according to the embodiment of the present invention are:

The present invention firstly uses concentrated sulfuric acid to carry out addition reaction with fluorine-containing olefins, and then carries out hydrolysis reaction on the obtained product to obtain perfluoroalkyl ethanol. The method can not only well control the reaction process and greatly shorten the reaction time, but also stabilize the yield of perfluoroalkyl ethanol.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

FIG1 is a gas chromatogram of perfluorohexylethanol of Example 2 of the present invention;

FIG. 2 is a flow chart of the preparation of perfluoroalkylethanol of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

The perfluoroalkylethanol according to the embodiment of the present invention and the preparation method thereof are described in detail below.

2, a method for preparing perfluoroalkylethanol provided in an embodiment of the present invention comprises the following steps:

S1, fluorinated olefin and concentrated sulfuric acid react under a nitrogen atmosphere to obtain an addition product.

Furthermore, in a preferred embodiment of the present invention, the fluorine-containing olefin is CF ₃ (CF ₂ ) _n CH＝CH ₂ , wherein n is one of 3, 5, 7 and 9.

Furthermore, in a preferred embodiment of the present invention, the mass percentage of the concentrated sulfuric acid is 96-99%. Preferably, the mass percentage of the concentrated sulfuric acid is 98%.

Furthermore, in a preferred embodiment of the present invention, the molar ratio of the fluorine-containing olefin to the concentrated sulfuric acid is 1:1-2.

Furthermore, in a preferred embodiment of the present invention, the reaction temperature is 80-160° C., and the reaction time is 12-24 hours.

S2. After adding the addition product into a high-pressure reactor with magnetic stirring, slowly adding water to carry out a hydrolysis reaction. After standing and stratification, taking the lower layer of transparent solution, washing with water, and drying, to obtain perfluoroalkylethanol.

Furthermore, in a preferred embodiment of the present invention, the volume ratio of the water to the fluorine-containing olefin is 0.1 to 1:1.

Furthermore, in a preferred embodiment of the present invention, the temperature of the hydrolysis reaction is 160-180° C., and the reaction time is 12-18 hours.

Furthermore, in a preferred embodiment of the present invention, the drying step specifically includes: the lower transparent solution is washed with water, and then anhydrous magnesium sulfate is added to absorb water and dry to obtain perfluoroalkylethanol.

The present invention firstly utilizes sulfuric acid and fluorine-containing olefins to carry out addition reaction, and then carries out hydrolysis reaction to obtain perfluoroalkyl ethanol. The method can not only well control the reaction process and greatly shorten the reaction time, but also stabilize the yield of perfluoroalkyl ethanol.

The present invention also provides a perfluoroalkylethanol, which is prepared according to the preparation method, and the chemical structure of the perfluoroalkylethanol is as follows:

Here, n is one of 3, 5, 7, and 9.

The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

Example 1

A perfluoroalkylethanol provided in this embodiment is prepared according to the following method:

(1) Add fluorinated olefin and 98% concentrated sulfuric acid into a three-necked flask, pass nitrogen, and react at 80°C for 18 hours. The fluorinated olefin is CF ₃ (CF ₂ ) ₃ CH＝CH ₂ , and the molar ratio of the fluorinated olefin to the concentrated sulfuric acid is 1:1.

(2) Add the product obtained in step S1 to a high-pressure reactor with magnetic stirring, slowly add water to the autoclave and react at 160° C. for 12 hours. The volume ratio of water to fluorinated olefin added to the autoclave is 0.1:1. After the reaction is completed, let it stand, separate the layers, take the transparent solution layer, wash it with water, add anhydrous magnesium sulfate to absorb water and dry it, and obtain perfluoroalkylethanol, whose chemical structure is as follows:

Example 2

In this embodiment, a perfluoroalkylethanol is provided, which is prepared according to the following method:

(1) Add fluorinated olefin and 98% concentrated sulfuric acid into a three-necked flask, pass nitrogen, and react at 160°C for 20 hours. The fluorinated olefin is CF ₃ (CF ₂ ) ₅ CH＝CH ₂ , and the molar ratio of the fluorinated olefin to the concentrated sulfuric acid is 1:1.2.

(2) Add the product obtained by the reaction in step S1 to a high-pressure reactor with magnetic stirring, slowly add water to the autoclave and react at 165° C. for 18 hours. The volume ratio of water to fluorinated olefin added to the autoclave is 0.5:1. After the reaction is completed, let it stand and separate into layers. Wash the lower layer of transparent solution with water, add anhydrous magnesium sulfate to absorb water and dry it to obtain perfluoroalkylethanol (perfluorohexylethanol, FIG1 shows its gas chromatogram), and its chemical structure is as follows:

Example 3

In this embodiment, a perfluoroalkylethanol is provided, which is prepared according to the following method:

(1) Add fluorinated olefin and 98% concentrated sulfuric acid into a three-necked flask, pass nitrogen, and react at 100°C for 24 hours. The fluorinated olefin is CF ₃ (CF ₂ ) ₇ CH＝CH ₂ , and the molar ratio of the fluorinated olefin to the concentrated sulfuric acid is 1:1.5.

(2) Add the product obtained in step S1 to a high-pressure reactor with magnetic stirring, slowly add water to the autoclave and react at 170° C. for 16 hours. The volume ratio of water to fluorinated olefin added to the autoclave is 0.8:1. After the reaction is completed, let it stand, separate the layers, take the transparent solution layer, wash it with water, add anhydrous magnesium sulfate to absorb water and dry it, and obtain perfluoroalkylethanol, whose chemical structure is as follows:

Example 4

In this embodiment, a perfluoroalkylethanol is provided, which is prepared according to the following method:

(1) Add fluorinated olefin and 98% concentrated sulfuric acid into a three-necked flask, pass nitrogen, and react at 120° C. for 12 h. The fluorinated olefin is CF ₃ (CF ₂ ) ₉ CH＝CH ₂ , and the molar ratio of the fluorinated olefin to the concentrated sulfuric acid is 1:2.

(2) Add the product obtained in step S1 to a high-pressure reactor with magnetic stirring, slowly add water to the autoclave and react at 180° C. for 15 hours. The volume ratio of water to fluorinated olefin added to the autoclave is 1:1. After the reaction is completed, let it stand, separate the layers, take the transparent solution layer, wash it with water, add anhydrous magnesium sulfate to absorb water and dry it, and obtain perfluoroalkylethanol, whose chemical structure is as follows:

The embodiments described above are part of the embodiments of the present invention, rather than all of the embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims (7)

1. A method for preparing perfluoroalkyl ethanol, which is characterized by comprising the following steps:

S1, reacting fluorine-containing olefin with concentrated sulfuric acid under a nitrogen atmosphere to obtain an addition product, wherein the fluorine-containing olefin is CF ₃(CF₂)_nCH＝CH₂, and n is one of 3,5,7 and 9;

S2, adding the addition product into a high-pressure reaction kettle with magnetic stirring, slowly adding water for hydrolysis reaction, standing, layering, taking a lower transparent solution, washing with water, and drying to obtain perfluoroalkyl ethanol, wherein the chemical structural formula of the perfluoroalkyl ethanol is as follows:

Wherein n is one of 3,5,7, 9.

2. The method for producing perfluoroalkyl ethanol according to claim 1, wherein in step S1, the mass percentage of the concentrated sulfuric acid is 96-99%.

3. The method for producing perfluoroalkyl ethanol according to claim 1, wherein in step S1, the molar ratio of the fluoroolefin to the concentrated sulfuric acid is 1:1-2.

4. The process for producing perfluoroalkyl ethanol according to claim 1, wherein in step S1, the reaction temperature is 80-160 ℃ and the reaction time is 12-24 hours.

5. The method for producing perfluoroalkyl ethanol according to claim 1, wherein the volume ratio of the water to the fluorine-containing olefin is 0.1-1:1.

6. The process for producing perfluoroalkyl ethanol according to claim 1, wherein in step S2, the hydrolysis reaction is carried out at 160 to 180 ℃ for 12 to 18 hours.

7. The method for producing perfluoroalkyl ethanol according to claim 1, wherein in step S2, the step of drying specifically comprises: and washing the lower transparent solution with water, adding anhydrous magnesium sulfate, and drying to obtain the perfluoroalkyl alcohol.