阅读说明：本技术 一种去除1,1,2,3,3,3-六氟丙基氢氟醚粗品中不饱和杂质的方法 (Method for removing unsaturated impurities in 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether crude product ) 是由 李义涛 唐尤健 侯琴卿 阳峰 贾渊 于 2020-04-16 设计创作，主要内容包括：本发明提供一种去除1,1,2,3,3,3-六氟丙基氢氟醚粗品中不饱和杂质的方法,通过使用柱层析这一种物理方法使1,1,2,3,3,3-六氟丙基氢氟醚和1,1,2,3,3-五氟丙烯氢氟醚或1,2,3,3,3-五氟丙烯氢氟醚杂质能够很好的分离,制备纯度在99％以上的1,1,2,3,3,3-六氟丙基氢氟醚产物。本发明方法不使用危险化学,极大的提高了操作的安全性,同时不产生对环境有害的废弃物,吸附剂硅胶柱能够再生重复使用,减少了成本,节约了资源。(The invention provides a method for removing unsaturated impurities in a 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether crude product, which can separate 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether from 1,1,2,3, 3-pentafluoropropylene hydrofluoroether or 1,2,3, 3-pentafluoropropylene hydrofluoroether impurities well by using a physical method of column chromatography to prepare a 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether product with the purity of more than 99%. The method of the invention does not use dangerous chemistry, greatly improves the operation safety, does not generate wastes harmful to the environment, can regenerate and reuse the adsorbent silica gel column, reduces the cost and saves the resources.)

1. A process for removing unsaturated impurities from a crude 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether, comprising: and (3) removing unsaturated impurities in the crude product of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether by using fluorine-containing silica gel as an adsorbent and using a column chromatography method.

2. The method according to claim 1, wherein the adsorbent further comprises standard silica gel, and the volume ratio of the fluorine-containing silica gel to the standard silica gel is 1: (0.5-1).

3. The method of claim 1, wherein the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether has the formula: CF (compact flash)₃CHFCF₂OCH₂R, the structural formula of the unsaturated impurity is as follows: CF (compact flash)₂＝CFCF₂OCH₂R and/or CF₃CF＝CFOCH₂R, wherein R is-C_aH_bF_cA and c are independently selected integers greater than or equal to 0, b is selected integers greater than or equal to 1, and b + c is 2a + 1.

4. The method of claim 3, wherein a is an integer from 0 to 10.

5. The method of claim 3, wherein R is selected from the group consisting of: -H, -CH₃、-CH₂CH₃、-CH₂CH₂CH₃、-CF₃、-CF₂CF₃、-CF₂CF₂CF₃、-CF₂(CF₂)₂CF₃、-CF₂(CF₂)₃CF₃、-CF₂(CF₂)₄CF₃、-CF₂(CF₂)₅CF₃、-CF₂CHF₂。

6. The method of claim 1, wherein the fluorine-containing silica gel is a fluorinated silica gel.

Technical Field

The invention relates to a method for removing impurities in a fluoroalkyl ether crude product, and in particular relates to a method for removing unsaturated impurities in a 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether crude product.

Background

The prior art method for removing unsaturated impurities in crude 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether comprises the following steps:

(1) adding unsaturated impurities by using chlorine before rectifying the crude product of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether.

(2) And adding unsaturated impurities by using bromine before rectifying the crude product of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether.

(3) The pure product is obtained by rectifying the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether treated by n-hexylamine.

In the method (1), chlorine gas is used, the pressure and the temperature are increased to the boiling point of 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether for reaction, energy consumption is needed, or a high-pressure mercury lamp is used for reaction under the irradiation of ultraviolet light, the used chlorine gas is large in amount and needs to be absorbed, the chlorine gas is high in corrosivity, the requirement on equipment is high, and the reaction is unsafe. In the method (2), the bromine is required to contact with the outside air when in use, a large amount of volatile bromine is harmful to the health of human bodies, and the cost is high. The method (3) is also expensive and is not suitable for industrial treatment.

Therefore, there is a need to develop a new method for removing unsaturated impurities from crude 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a method for removing unsaturated impurities in a 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether crude product.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

and (3) removing unsaturated impurities in the crude product of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether by using fluorine-containing silica gel as an adsorbent and using a column chromatography method.

Preferably, the adsorbent further comprises standard silica gel.

More preferably, the volume of the fluorine-containing silica gel is larger than that of the standard silica gel.

Further preferably, the volume ratio of the fluorine-containing silica gel to the standard silica gel is preferably 1: (0.5-1).

The structural formula of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether is CF₃CHFCF₂OCH₂R, said unsaturated impurities are mainly unsaturated compounds, including CF₂＝CFCF₂OCH₂R、CF₃CF＝CFOCH₂One or two of R, wherein R is-C_aH_bF_cA and c are independently selected integers greater than or equal to 0, b is selected integers greater than or equal to 1, and b + c is 2a + 1.

From the viewpoint of ease of preparation, a is preferably an integer of 0 to 10, particularly preferably an integer of 0 to 5.

Non-limiting examples of R include: -H, -CH₃、-CH₂CH₃、-CH₂CH₂CH₃、-CF₃、-CF₂CF₃、-CF₂CF₂CF₃、-CF₂(CF₂)₂CF₃、-CF₂(CF₂)₃CF₃、-CF₂(CF₂)₄CF₃、-CF₂(CF₂)₅CF₃、-CF₂CHF₂。

Preferably, the fluorine-containing silica gel is fluorinated silica gel.

In the chromatographic column method, a dry method is adopted for column packing, and after the column packing is finished, a corresponding saturated hydrofluoroether solvent is used for washing and the silica gel column is pumped to be solid. The corresponding saturated hydrofluoroether solvent is a saturated hydrofluoroether solvent corresponding to a hydrofluoroether crude product to be purified, and has high purity.

In some embodiments, the crude 1,1,2,3,3, 3-hexafluoropropyl methyl ether is purified by washing with 1,1,2,3,3, 3-hexafluoropropyl methyl ether solvent (HFE-356MEC) and consolidating the silica gel column.

In some embodiments, the crude 1,1,2,3,3, 3-hexafluoropropylethyl ether is purified by washing with 1,1,2,3,3, 3-hexafluoropropylethyl ether solvent and tapping the silica gel column.

In some embodiments, the crude 1,1,2,3,3, 3-hexafluoropropyl trifluoroethyl ether is purified by washing with 1,1,2,3,3, 3-hexafluoropropyl trifluoroethyl ether solvent (HFE-449MEC) and drawing down the silica gel column.

The boiling points of the saturated 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether and the unsaturated 1,1,2,3, 3-pentafluoropropenyl hydrofluoroether or 1,2,3,3, 3-pentafluoropropenyl hydrofluoroether are very close, and the saturated 1,1,2,3, 3-hexafluoropropyl hydrofluoroether and the unsaturated 1,1,2,3, 3-pentafluoropropenyl hydrofluoroether cannot be separated and purified by using a conventional rectification method. The method of the invention avoids using a rectification method to separate the saturated fluoroether 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether and the unsaturated pentafluoropropylhydrofluoroether, adopts a physical adsorption method, and performs extraction operation of a fluorine solid phase on the crude product of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether according to the difference of the polarities of the saturated hydrofluoroether 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether and the unsaturated pentafluoropropylhydrofluoroether, so as to obtain the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether with the purity of more than 99 percent, and the separation method is simple and convenient.

The invention has the beneficial effects that:

1. the physical method of column chromatography is used to separate the impurities of 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether and unsaturated hydrofluoroether well and prepare 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether product with purity over 99%.

2. Dangerous chemicals such as bromine and chlorine are not used, the operation safety is greatly improved, wastes harmful to the environment are not generated, the adsorbent silica gel column can be regenerated and reused, the cost is reduced, and resources are saved.

Definition of terms

All ranges cited herein are inclusive, unless expressly stated to the contrary.

The terms "a" or "an" are used herein to describe elements and components described herein. This is done merely for convenience and to provide a general sense of the scope of the invention. Such description should be understood to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. "plural" means two or more.

The numbers in this disclosure are approximate, regardless of whether the word "about" or "approximately" is used. The numerical value of the number may have differences of 1%, 2%, 5%, 7%, 8%, 10%, etc. Whenever a number with a value of N is disclosed, any number with a value of N +/-1%, N +/-2%, N +/-3%, N +/-5%, N +/-7%, N +/-8% or N +/-10% is explicitly disclosed, wherein "+/-" means plus or minus, and a range between N-10% and N + 10% is also disclosed.

The following definitions, as used herein, should be applied unless otherwise indicated. For the purposes of the present invention, the chemical elements are in accordance with the CAS version of the periodic Table of elements, and the 75 th version of the handbook of chemistry and Physics, 1994. In addition, general principles of Organic Chemistry can be referred to as described in "Organic Chemistry", Thomas Sorrell, University Science Books, Sausaltito: 1999, and "March's Advanced Organic Chemistry" by Michael B.Smith and Jerry March, John Wiley & Sons, New York:2007, the entire contents of which are incorporated herein by reference.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can also be used in the practice or testing of embodiments of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety, unless a specific section is cited. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The preparation method of the crude product of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether comprises the following steps:

with hexafluoropropylene (CF)₃CFH＝CF₂) As raw material, with alkyl alcohol (RCH)₂OH) is prepared by addition reaction in a solvent under the action of a catalyst, wherein the molar ratio of hexafluoropropylene to alkyl alcohol to the solvent is 1 (1-5) to (2-5), the reaction temperature is-30-100 ℃, preferably 20-60 ℃, and the reaction pressure is 0.1-0.6 Mpa.

Wherein R is the same as R in the structural formula of the 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether, namely R is-C_aH_bF_cA and c are independently selected from greater than or equal toAn integer equal to 0, b is selected from integers greater than or equal to 1, and b + c is 2a + 1. From the viewpoint of ease of preparation, a is preferably an integer of 0 to 10, particularly preferably an integer of 0 to 5.

The alkyl alcohol may be a fluorine-containing alkyl alcohol or a non-fluorine-containing alkyl alcohol. The non-fluoroalkyl alcohol may be methanol, ethanol, propanol, propylene glycol or n-butanol, more preferably methanol, ethanol or propanol. The fluoroalkyl alcohol may be CF₃CH₂OH、CF₃CF₂CH₂OH、CF₃(CF₂)₂CH₂OH、CF₃(CF₂)₃CH₂OH、CF₃(CF₂)₄CH₂OH、CF₃(CF₂)₄CH₂OH、CF₃(CF₂)₅CH₂OH、CF₃(CF₂)₆CH₂OH or CHF₂CF₂CH₂OH, more preferably CF₃CH₂OH。

The catalyst may be a basic catalyst or an alkali metal salt catalyst. The basic catalyst may be an alkali metal/alkaline earth metal hydroxide, and the alkali metal salt catalyst may be an alkali metal/alkaline earth metal alkoxide, from the viewpoint of the applicability and strength of the reaction. The alkali metal or alkaline earth metal includes Li, Na, K, Ca, Mg and Cs, and preferably K, Ca and Na.

The solvent is an aprotic polar solvent, preferably one or more of ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dioxane, tetrahydrofuran, acetonitrile, propionitrile, butyronitrile, dimethyl sulfoxide and N, N-dimethylformamide. Acetonitrile is more preferable as the solvent from the viewpoint of further optimizing the reaction, facilitating the post-treatment, and the like.

Comparative example 1

Preparation of a hydrofluoroether crude:

adding 100g of potassium hydroxide, 500g of methanol and 2000g of acetonitrile solvent into a high-pressure reaction kettle, checking the air tightness of the reaction kettle, pumping the air pressure in the reaction kettle to vacuum by using a vacuum pump, raising the temperature to 40 ℃, introducing 1500g of hexafluoropropylene, and reacting while stirring until the pressure is not reduced any more. The reaction solution was collected and washed with water to remove methanol. After washing with water, 1800g of crude 1,1,2,3,3, 3-hexafluoropropyl methyl ether was obtained. GC detection analysis shows that the content of 1,1,2,3,3, 3-hexafluoropropyl methyl ether in the crude product is 86.33%, the total content of 1,1,2,3, 3-pentafluoropropenyl methyl ether and/or 1,2,3,3, 3-pentafluoropropenyl methyl ether is 7.5%, and the content of other impurities is 6.17%.

Removing unsaturated impurities:

weighing 1500g of the crude product of the 1,1,2,3,3, 3-hexafluoropropyl methyl ether, preparing a chromatographic column with the diameter of 10cm and the height of 1m, filling the column by adopting a dry method by using an adsorbent which is standard silica gel, and filling the column to the position of 20cm left at the upper end of an ion column. Washing with HFE-356MEC after filling, evacuating the lower end of the column with a vacuum pump, repeating for 3 times to compact the silica gel column, pouring the weighed crude 1,1,2,3,3, 3-hexafluoropropyl methyl ether, collecting the product from below, pouring the product from above the column, and repeating for 3 times. TLC plates confirmed separation of the two components.

The GC results before and after purification of the crude 1,1,2,3,3, 3-hexafluoropropyl methyl ether are shown in Table 1 below.

TABLE 1

Comparative example 2

Fluorinated silica gel and standard silica gel in a volume ratio of 1:2 were uniformly mixed to serve as an adsorbent, and the preparation of a hydrofluoroether crude product and the removal method of saturated impurities were the same as in comparative example 1.

The GC results before and after purification of the crude 1,1,2,3,3, 3-hexafluoropropyl methyl ether are shown in Table 2 below.

TABLE 2

Example 1

The preparation of the crude hydrofluoroether and the removal of unsaturated impurities were performed in the same manner as in comparative example 1, using fluorinated silica gel as the adsorbent.

The GC results before and after purification of the crude 1,1,2,3,3, 3-hexafluoropropyl methyl ether are shown in Table 3 below.

TABLE 3

Example 2

Preparation of a hydrofluoroether crude:

adding 50g of potassium hydroxide, 500g of ethanol and 1500g of dimethyl sulfoxide (DMSO) into a high-pressure reaction kettle, checking the air tightness of the reaction kettle, pumping the air pressure in the reaction kettle to vacuum by using a vacuum pump, raising the temperature to 40 ℃, introducing 1500g of hexafluoropropylene, and reacting while stirring until the pressure is not reduced any more. The reaction solution was collected and washed with water to remove ethanol. 1750g of crude 1,1,2,3,3, 3-hexafluoropropylethyl ether was obtained. GC analysis showed that the crude product contained 80.33% 1,1,2,3,3, 3-hexafluoropropylethyl ether, 8.5% total 1,1,2,3, 3-pentafluoropropylethyl ether and/or 1,2,3,3, 3-pentafluoropropylethyl ether and 11.17% other impurities.

Removing unsaturated impurities:

1500g of the crude 1,1,2,3,3, 3-hexafluoropropyl ethyl ether product was weighed, a chromatography column having a diameter of 10cm and a height of 1m was prepared, and fluorinated silica gel and standard silica gel in a volume ratio of 1:1 were uniformly mixed to prepare an adsorbent. And (5) filling the column by a dry method until the position of 20cm left at the upper end of the ion column. And after the filling is finished, washing the column by using a 1,1,2,3,3, 3-hexafluoropropyl ethyl ether solvent, pumping air from the lower end of the column by using a vacuum pump, repeatedly pumping the silica gel column for 3 times, pouring weighed 1,1,2,3,3, 3-hexafluoropropyl ethyl ether crude product into the column, collecting the product from the lower part, pouring the product from the upper part of the chromatographic column, and repeatedly repeating for 3 times. TLC plates confirmed separation of the two components.

The GC results before and after purification of the crude 1,1,2,3,3, 3-hexafluoropropylethyl ether are shown in Table 4 below.

TABLE 4

Example 3

Preparation of a hydrofluoroether crude:

adding 100g of potassium hydroxide, 1000g of trifluoroethanol and 2000g of acetonitrile into a high-pressure reaction kettle, checking the air tightness of the reaction kettle, vacuumizing the pressure in the reaction kettle by using a vacuum pump, introducing 1500g of hexafluoropropylene at room temperature, and reacting while stirring until the pressure is not reduced any more. The reaction solution was collected, and the trifluoroethanol was removed by washing with water. A total of 2000g of crude 1,1,2,3,3, 3-hexafluoropropyl trifluoroethyl ether was obtained. GC detection analysis shows that the content of 1,1,2,3,3, 3-hexafluoropropyl trifluoroethyl ether in the crude product is 83.77%, the total content of 1,1,2,3, 3-pentafluoropropenyl trifluoroethyl ether and/or 1,2,3,3, 3-pentafluoropropenyl trifluoroethyl ether is 2.60%, and the content of other impurities is 13.63%.

Removing unsaturated impurities:

1500g of the crude 1,1,2,3,3, 3-hexafluoropropyl trifluoroethyl ether product prepared above is weighed, a chromatographic column with the diameter of 10cm and the height of 1m is prepared, and fluorinated silica gel and standard silica gel in the volume ratio of 2:1 are uniformly mixed to be used as an adsorbent. And (5) filling the column by a dry method until the position of 20cm left at the upper end of the ion column. Washing with HFE-449MEC after filling, evacuating with vacuum pump at the lower end of the column, repeating for 3 times to evacuate the silica gel mixed column, pouring 1,1,2,3,3, 3-hexafluoropropyl trifluoroethyl ether crude product, collecting the product from below, pouring the product from above the chromatographic column, and repeating for 3 times. TLC plates confirmed separation of the two components.

The GC results before and after purification of the crude 1,1,2,3,3, 3-hexafluoropropyl trifluoroethyl ether are shown in Table 5 below.

TABLE 5

As is clear from examples 1 to 3 and comparative examples 1 to 2, when the volume of the fluorine-containing silica gel is larger than that of the standard silica gel, the purity of the purified 1,1,2,3,3, 3-hexafluoropropyl hydrofluoroether is 99% or more, and the volume ratio of the fluorine-containing silica gel to the standard silica gel is preferably 1: (0.5-1).