CN111302888B - Separation method of high-purity electronic grade hexafluoropropane isomer - Google Patents
Separation method of high-purity electronic grade hexafluoropropane isomer Download PDFInfo
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- C07C17/35—Preparation of halogenated hydrocarbons by reactions not affecting the number of carbon or of halogen atoms in the reaction
- C07C17/358—Preparation of halogenated hydrocarbons by reactions not affecting the number of carbon or of halogen atoms in the reaction by isomerisation
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- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
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- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
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- B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
Abstract
The invention provides a method for separating high-purity electronic grade hexafluoropropane isomers, which comprises the following steps: s1: washing with water to remove acid; s2: adsorption dehydration; s3: catalytic conversion converts isomers into a specified structure; s4: rectifying to remove other impurities; wherein, in step S3, a catalytic converter is used, which is in the form of a fixed bed reactor, wherein the surface active component of the packed catalyst is platinum, and the loading is 0.2-0.8 wt%. The separation method has the characteristics of high production efficiency, high directional purification depth and stable process performance.
Description
Technical Field
The invention belongs to the field of hexafluoropropane purification, and particularly relates to a method for separating high-purity electronic grade hexafluoropropane isomers.
Background
The high-purity electronic grade 1,1,1,3,3, 3-hexafluoropropane has a structural formula
Molecular formula C3H2F6HFC-236fa is the only special gas of fluorocarbon with F/C ratio of 2 in saturated three-carbon alkane electronic chemicals. C3H2F6As a new generation of plasma etching gas, because of its unique chemical structure, it has excellent safety, etching rate, selectivity and sidewall characteristics, and has attracted much attention in recent years, such as U.S. patents: US20170365487a1, US6361705B 1.
C3H2F6The gas is saturated alkane, relatively inert in chemical property and hasHas excellent stability and extremely low toxicity, and is an aerospace carrying fire extinguishing agent which is relatively friendly to human health. The gas is convenient to transport and manage, the matched pipeline, the pipe fitting and the gas cabinet filling system are basically consistent with other fluorocarbon electronic special gases, sharing can be achieved, upgrading and updating of terminal electronic customer gas are facilitated, and the gas has good safety for operators. C3H2F6Is a relatively green environment-friendly gas which is compared with the conventional SF6、C2F6The etching gas has a lower GWP value (hexafluoropropane 9400, sulfur hexafluoride 22000, hexafluoroethane 11900) and a shorter atmospheric lifetime than the etching gas. At the same time, C3H2F6Due to the unique F/C ratio, the silicon nitride/carbon composite material has excellent etching rate, selectivity and side wall characteristics in etching application.
At present, C3H2F6Is mainly used in 3D NAND etching. In a conventional contact hole etch (contact hole etch) or trench etch (trench etch), it is difficult to control the aspect ratio (high aspect ratio) above 20 because the polymer deposited on the sidewall has insufficient barrier protection. Conventional etching gases, e.g. octafluorocyclobutane (C-C)4F8) Carbon tetrafluoride (CF)4) Difluoromethane (CH)2F2) Trifluoromethane (CHF)3) Monofluoromethane (CH)3F) And hexafluorobutadiene (C)4F6) Sidewall polymer-CxFy-can be produced, where x ranges from 0.01 to 1 and y ranges from 0.01 to 4. These sidewall polymers are susceptible to deformation under plasma etching. As the atomic ratio of carbon to fluorine increases, the polymer deposition rate and the sidewall selectivity gradually increase, for example: c4F6>C4F8>CF4. However, when the conventional high selectivity etching gas is selected for use, the etched pattern will not be very vertical due to the sensitivity change of the sidewall polymer, but a bowl shape is etched. When the size of the etching hole or groove is changed, the etching hole channel is easy to collapse, and the roughness of the inner wall of the hole becomes serious. To sum up, C3H2F6As one in 3D NANDThe etching gas for high-depth wide-contact hole can reduce the phenomenon of undesirable etching of bowl shape and SiO2The continuous and smooth side wall is etched between the/SiN stacking layers, the continuous and smooth side wall is the first choice of a new generation of etching gas in the 3D NAND manufacturing process, and the future market application prospect is wide.
Among them, hexafluoropropane has three kinds of isomers in total according to the difference in the hydrogen atom position, and the separation coefficient between related isomers is extremely low as shown in table 1.
TABLE 1 Structure of three hexafluoropropane isomers
In the past, only the production of 1,1,1,3,3, 3-hexafluoropropane and 1,1,1,2,3, 3-hexafluoropropane have been reported for hexafluoropropane.
Patent for 1,1,1,3,3, 3-hexafluoropropane is CN201811502795.0, and the invention discloses a method for preparing 1,1,1,3,3, 3-hexafluoropropane, which comprises the following steps: (1) reacting halogen-containing inorganic salt and heptafluoro isobutylene methyl ether in an aprotic solvent, adding water after the reaction is finished, stirring, cooling, filtering, and rectifying the filtrate to obtain hexafluoroisobutyric acid; (2) heating hexafluoroisobutyric acid obtained in the step (1), collecting a generated gas-phase product and cooling to obtain a1, 1,1,3,3, 3-hexafluoropropane product. Patent application CN201410033221.9 provides a process for producing 1,1,1,3,3, 3-hexafluoropropane, which comprises reacting 1,1,1,3,3, 3-hexachloropropane with hydrogen fluoride in the presence of a catalyst, wherein the catalyst comprises antimony pentafluoride and tin tetrafluoride. The preparation method can improve the conversion rate of the 1,1,1,3,3, 3-hexafluoropropane, and the 1,1,1,3,3, 3-hexafluoropropane prepared by the method can be used as a refrigerant and a fire extinguishing agent.
For the patent application of 1,1,1,2,3, 3-hexafluoropropane, there is disclosed a process for preparing 1,1,1,2,3, 3-hexafluoropropane, having publication number CN201611179120.8, which comprises the steps of: (1) inert fillers are respectively mixed with hydrogenation catalysts at different dilution ratios, and the hydrogenation catalysts at different dilution ratios are respectively filled in the heat exchange type fixed bed reactor in sections; (2) mixing and preheating hexafluoropropylene and hydrogen, introducing the mixture into a hydrogenation catalyst reactor at a low concentration end, and performing gas phase catalytic hydrogenation reaction at the temperature of 50-250 ℃ to generate 1,1,1,2,3, 3-hexafluoropropane which is discharged from a high concentration catalyst end of the reactor; (3) the heat generated by the reactor is exchanged with a cooling medium. Patent application publication No. CN201010202918.6 relates to a method for producing 1,1,1,2,3, 3-hexafluoropropane, and specifically, to a method for producing 1,1,1,2,3, 3-hexafluoropropane by: reacting hexafluoropropylene with a superstoichiometric amount of hydrogen in the gas phase in the presence of a hydrogenation catalyst in a reactor; and recycling a portion of the gaseous output stream from the reactor. Patent application publication No. CN200780040776.4 discloses reacting tetrafluoroethylene with difluoromethane in the presence of at least one by-product and a suitable antimony pentafluoride catalyst. Preparing 1,1,1,2,2, 3-hexafluoropropane. There are also patent applications relating to hexafluoropropane equipments, such as CN201720036685.4 a hexafluoropropane container valve, CN201820278360.1 a cabinet type hexafluoropropane gas fire extinguishing apparatus, etc.
In the synthesis of 1,1,1,3,3, 3-hexafluoropropane or 1,1,1,2,3, 3-hexafluoropropane, a large amount of fluorocarbon and semi-fluorocarbon byproducts are generated, and although the generated hexafluoropropane mainly exists in one isomer, the selectivity is not strong, and the high-purity electronic grade of the other isomer cannot be achieved. Due to the particularity of the molecular structure of hexafluoropropane, only two hydrogen atoms are in different positions, the separation coefficient of three isomers is low, and the separation difficulty is high. Currently, only one CN201180026190.9 report on the separation and purification of hexafluoropropane is the purification of azeotropic or azeotrope-like mixture of 1,1,1,2,3, 3-hexafluoropropane and hydrogen fluoride in the present invention, but the separation method of isomers is not involved. At present, no report on the directional conversion, separation and purification of hexafluoropropane isomers exists.
In summary, the technical problem faced by the present hexafluoropropane purification is the separation and purification of three isomers, which finally meets the manufacturing requirements of the semiconductor electronic industry. However, the difference between the structure and the boiling point of different isomers of hexafluoropropane is very small, and the separation of the isomers is difficult by conventional low-temperature rectification, which is a technical problem to be solved urgently.
Disclosure of Invention
In view of the above, the present invention aims to provide a method for separating high purity electronic grade hexafluoropropane isomers, so as to solve the technical problems in the prior art that the difference between the structure and the boiling point of different isomers in the hexafluoropropane purification is very small, and the separation of the isomers is difficult by the conventional low temperature rectification.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the noble metal platinum is selected as an active center, hexafluoropropane is changed into a carbocation, and different types of carbocations have different stability (tertiary carbon > secondary carbon > primary carbon). Depending on the rearrangement characteristics of the carbenium ion, the hydrogen atom can eventually be moved to a secondary carbon position. The mechanism is as follows:
the specific mechanism is as follows: at the active center of the platinum catalyst, hydrogen atoms are removed, and the carbon chain becomes a carbocation. The side chain can be transferred, so that the positive ion is positioned at the middle carbon atom to form a secondary carbon positive ion, and because the secondary carbon ion is relatively stable, the adjacent hydrogen atom can be transferred to the secondary carbon position, and finally the directional conversion of the 1,1,1,3,3, 3-hexafluoropropane is realized.
In order to remove trace amount of isomer by matching conversion, the noble metal used is a platinum catalyst, and the key is to determine the platinum loading amount of the active center and also have a carrier form (silicon-aluminum ratio and specific surface area) with an enhancing effect. In addition, the catalyst is easy to inactivate noble metal platinum due to the impurity HF, so that the invention limits the sequence of the separation units, and the separation is realized by sequentially carrying out water washing, adsorption, catalytic conversion and rectification unit operations. Wherein the water washing is to remove HF, and the adsorption is to remove trace amount after water washingThoroughly removing water and unwashed HF, performing catalytic conversion to directionally convert into 1,1,1,3,3, 3-hexafluoropropane, and finally further removing light and heavy impurities by a rectification method, wherein the light component is such as H2、N2、O2、CO2And the like, and the compositions are octafluoropropane, octafluorocyclobutane and the like. Finally, the electronic grade hexafluoropropane with the purity of more than 99.99 percent can be obtained, and the requirements of advanced semiconductor manufacturing processes can be met.
A method for separating high-purity electronic grade hexafluoropropane isomeride comprises the following steps:
s1: washing with water to remove acid: introducing a hexafluoropropane raw material to be purified into a water washing tower for water washing to remove acid;
s2: adsorption and dehydration: introducing the washed raw materials into an adsorption tower for dehydration;
s3: catalytic conversion converts isomers into a specified structure;
s4: rectifying to remove light component impurities and heavy component impurities;
wherein, in step S3, a catalytic converter is used, which is in the form of a fixed bed reactor, wherein the active center of the catalyst packed therein is platinum, and the loading is 0.2-0.8 wt%, preferably 0.5-0.8 wt%.
Further, the carrier of the catalyst used in the step S3 is an inert material containing aluminum, and the ratio of the carrier silicon to the carrier aluminum is 5-10.
Further, the specific surface area of the catalyst in the step S3 is 200-500m2/g。
Further, the gas space velocity of the catalytic converter in the step S3 is 50-200h-1。
Further, the catalytic conversion temperature in the step S3 is 400-600 ℃.
Preferably, the catalytic conversion temperature in the step S3 is 450-500 ℃.
Further, the catalytic conversion pressure in the step S3 is 0.1-0.3 MPa; preferably 0.2 MPa.
In step S2, the dehydration is performed using an adsorption column in which the adsorbent is a 3A, 4A, 5A, or 13X adsorbent.
Furthermore, the carrier in the catalytic conversion tower is alumina, aluminum boehmite or zeolite molecular sieve.
Further, the rectifying tower system in the step S4 includes a light component impurity removal rectifying tower for removing light component impurities and a heavy component impurity removal rectifying tower for removing heavy component impurities, wherein the process conditions of the two towers are 0.1-1.0MPa, and the operation temperatures of the tower top and the tower bottom are-20 ℃ to 40 ℃.
Compared with the prior art, the method for separating the high-purity electronic grade hexafluoropropane isomer has the following advantages:
the separation method has the characteristics of high production efficiency, high directional purification depth and stable process performance.
Detailed Description
Unless defined otherwise, technical terms used in the following examples have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods are conventional methods unless otherwise specified.
Wherein, the content analysis methods of the key impurities in the raw materials and the purified products are all conventional analysis methods in the gas industry. The specific content is according to GB/T3723 industrial chemical product sampling safety rule, GB/T5832.1 gas analysis trace moisture determination part 1: electrolytic method, measurement of trace moisture in GB/T5832.3 gas analysis part 3: cavity ring-down spectroscopy, gas chromatography for measuring carbon monoxide, carbon dioxide and hydrocarbon in GB/T8984 gas, helium ionization gas chromatography for GB/T28726 gas analysis, and infrared spectroscopy for GB/T6040.
The present invention will be described in detail with reference to examples.
The compositions of the raw materials used in the following examples are shown in the table below:
TABLE 2 composition of raw materials in respective examples and comparative examples
| Composition of raw materials | Content (ppm) |
| 1,1,1,2,3, 3-hexafluoropropane | 500 |
| 1,1,2,2,3, 3-hexafluoropropane | 43 |
| O2+Ar | 20 |
| N2 | 100 |
| CO2 | 20 |
| HF | 5 |
| H2O | 20 |
| Total content of isomers | 543 |
| Purity of 1,1,1,3,3, 3-hexafluoropropane | 99.9292％ |
Example 1
A method for separating high-purity electronic grade hexafluoropropane isomeride comprises the following steps:
s1: introducing the raw materials into a water washing tower for water washing to remove acid;
s2: introducing the raw material subjected to water washing into an adsorption tower for dehydration, wherein an adsorption material in the adsorption tower is a 3A adsorbent;
s3: introducing the dehydrated raw materials into a catalytic conversion tower, wherein the catalytic conversion tower is in a fixed bed reactor, the surface active component of the filled catalyst is platinum, the loading content is 0.2 wt%, the carrier is alumina, and the silica-alumina ratio of the carrier is 5; the gas space velocity of the catalytic conversion tower is 50h-1A specific surface area of 200m2The catalyst conversion temperature is 400 ℃ and the catalyst conversion pressure is 0.2 MPa.
S4: rectifying to remove other impurities, wherein the rectifying tower system comprises a light component removal rectifying tower and a heavy component removal rectifying tower, wherein the light component removal rectifying tower and the heavy component removal rectifying tower respectively remove light component impurities, the tower pressure of the light component removal rectifying tower is 0.1MPa, the tower bottom operating temperature of the tower top is-20 ℃, the tower pressure of the heavy component removal rectifying tower is 0.2MPa, and the tower bottom operating temperature of the tower top is 10 ℃.
Example 2
A method for separating high-purity electronic grade hexafluoropropane isomeride comprises the following steps:
s1: introducing the raw materials into a water washing tower for water washing to remove acid;
s2: introducing the raw material subjected to water washing into an adsorption tower for dehydration, wherein an adsorption material in the adsorption tower is a 4A adsorbent;
s3: introducing the dehydrated raw materials into a catalytic conversion tower, wherein the catalytic conversion tower is in a fixed bed reactor, the surface active component of the filled catalyst is platinum, the loading content is 0.3 wt%, the carrier is alumina, and the silica-alumina ratio of the carrier is 5; the gas space velocity of the catalytic conversion tower is 80h-1The specific surface area is 300m2The catalytic conversion temperature is 450 ℃ and the catalytic conversion pressure is 0.2 MPa.
S4: and (3) rectifying to remove other impurities, wherein the rectifying tower system comprises a light component removal rectifying tower and a heavy component removal rectifying tower, wherein the light component removal rectifying tower and the heavy component removal rectifying tower are used for respectively removing light component impurities, the tower pressure of the light component removal rectifying tower is 0.2MPa, the tower bottom operating temperature of the tower top is 20 ℃, the tower pressure of the heavy component removal rectifying tower is 0.3MPa, and the tower bottom operating temperature of the tower top is 30 ℃.
Example 3
A method for separating high-purity electronic grade hexafluoropropane isomers comprises the following steps:
s1: introducing the raw materials into a water washing tower for water washing to remove acid;
s2: introducing the raw material subjected to water washing into an adsorption tower for dehydration, wherein an adsorption material in the adsorption tower is a 4A adsorbent;
s3: introducing the dehydrated raw materials into a catalytic conversion tower, wherein the catalytic conversion tower is in a fixed bed reactor, the surface active component of the filled catalyst is platinum, the loading content is 0.5 wt%, the carrier is aluminum boehmite, and the silica-alumina ratio of the carrier is 8; the gas space velocity of the catalytic conversion tower is 100h-1A specific surface area of 350m2The catalytic conversion temperature is 480 ℃ and the catalytic conversion pressure is 0.2 MPa.
S4: and (3) rectifying to remove other impurities, wherein the rectifying tower system comprises a light component removal rectifying tower and a heavy component removal rectifying tower, wherein the light component removal rectifying tower and the heavy component removal rectifying tower are used for respectively removing light component impurities, the tower pressure of the light component removal rectifying tower is 0.2MPa, the tower bottom operating temperature of the tower top is 20 ℃, the tower pressure of the heavy component removal rectifying tower is 0.2MPa, and the tower bottom operating temperature of the tower top is 20 ℃.
Example 4
A method for separating high-purity electronic grade hexafluoropropane isomeride comprises the following steps:
s1: introducing the raw materials into a water washing tower for water washing to remove acid;
s2: introducing the raw material subjected to water washing into an adsorption tower for dehydration, wherein the adsorption material in the adsorption tower is a 4A adsorbent;
s3: introducing the dehydrated raw materials into a catalytic conversion tower, wherein the catalytic conversion tower is in a fixed bed reactor, the surface active component of the filled catalyst is platinum, the loading content is 0.6 wt%, the carrier is aluminum boehmite, and the silica-alumina ratio of the carrier is 8; the gas space velocity of the catalytic conversion tower is 120h-1Specific surface area of 400m2The catalytic conversion temperature is 500 ℃ and the catalytic conversion pressure is 0.2 MPa.
S4: and (3) rectifying to remove other impurities, wherein the rectifying tower system comprises a light component removal rectifying tower and a heavy component removal rectifying tower, wherein the light component removal rectifying tower and the heavy component removal rectifying tower are used for respectively removing light component impurities, the tower pressure of the light component removal rectifying tower is 0.2MPa, the tower bottom operating temperature of the tower top is 20 ℃, the tower pressure of the heavy component removal rectifying tower is 0.3MPa, and the tower bottom operating temperature of the tower top is 30 ℃.
Example 5
A method for separating high-purity electronic grade hexafluoropropane isomeride comprises the following steps:
s1: introducing the raw materials into a water washing tower for water washing to remove acid;
s2: introducing the raw material subjected to water washing into an adsorption tower for dehydration, wherein an adsorption material in the adsorption tower is a 4A adsorbent;
s3: introducing the dehydrated raw materials into a catalytic conversion tower, wherein the catalytic conversion tower is in a fixed bed reactor, the surface active component of the filled catalyst is platinum, the loading content is 0.6 wt%, the carrier is a zeolite molecular sieve, and the silica-alumina ratio of the carrier is 10; the gas space velocity of the catalytic conversion tower is 150h-1Specific surface area of 450m2The catalytic conversion temperature is 550 ℃ and the catalytic conversion pressure is 0.2 MPa.
S4: and (3) rectifying to remove other impurities, wherein the rectifying tower system comprises a light component removal rectifying tower and a heavy component removal rectifying tower, wherein the light component removal rectifying tower and the heavy component removal rectifying tower are used for respectively removing light component impurities, the tower pressure of the light component removal rectifying tower is 0.2MPa, the tower bottom operating temperature of the tower top is 20 ℃, the tower pressure of the heavy component removal rectifying tower is 0.3MPa, and the tower bottom operating temperature of the tower top is 30 ℃.
Example 6
A method for separating high-purity electronic grade hexafluoropropane isomeride comprises the following steps:
s1: introducing the raw materials into a water washing tower for water washing to remove acid;
s2: introducing the raw material subjected to water washing into an adsorption tower for dehydration, wherein an adsorption material in the adsorption tower is a 4A adsorbent;
s3: introducing the dehydrated raw material into a catalytic conversion tower in the form of a fixed bed reactor, wherein the surface active component of the filled catalyst is platinum and is loadedThe content is 0.8 wt%, the carrier is zeolite molecular sieve, and the silica-alumina ratio of the carrier is 10; the gas space velocity of the catalytic conversion tower is 200h-1Specific surface area of 500m2The catalyst conversion temperature is 600 ℃, and the catalyst conversion pressure is 0.3 MPa.
S4: and (3) rectifying to remove other impurities, wherein the rectifying tower system comprises a light component removal rectifying tower and a heavy component removal rectifying tower, wherein the light component removal rectifying tower and the heavy component removal rectifying tower are used for respectively removing light component impurities, the tower pressure of the light component removal rectifying tower is 0.2MPa, the tower bottom operating temperature of the tower top is 20 ℃, the tower pressure of the heavy component removal rectifying tower is 0.2MPa, and the tower bottom operating temperature of the tower top is 20 ℃.
Comparative example 1
A method for separating high-purity electronic grade hexafluoropropane isomeride comprises the following steps:
s1: introducing the raw materials into a water washing tower for water washing to remove acid;
s2: introducing the raw material subjected to water washing into an adsorption tower for dehydration, wherein an adsorption material in the adsorption tower is a 4A adsorbent;
s3: introducing the dehydrated raw materials into a catalytic conversion tower, wherein the catalytic conversion tower is in the form of a fixed bed reactor, and the catalyst filled in the catalytic conversion tower is a conventional zeolite molecular sieve catalyst; the gas space velocity of the catalytic conversion tower is 150h-1Specific surface area of 450m2The catalytic conversion temperature is 550 ℃ and the catalytic conversion pressure is 0.3 MPa.
S4: and (3) rectifying to remove other impurities, wherein the used rectifying tower system comprises a light component removal rectifying tower and a heavy component removal rectifying tower, wherein the light component removal rectifying tower and the heavy component removal rectifying tower are used for respectively removing light component impurities, the tower pressure of the light component removal rectifying tower is 0.2MPa, the tower bottom operating temperature of the tower top is 20 ℃, the tower pressure of the heavy component removal rectifying tower is 0.3MPa, and the tower bottom operating temperature of the tower top is 30 ℃.
The hexafluoropropane products obtained in examples 1 to 6 and comparative example 1 were tested for impurity content and purity, and the test results are shown in Table 3.
TABLE 3 impurity levels and purities (in ppm) in the examples and comparative examples
As can be seen from table 2, comparative example 1 has no catalyst with platinum as an active center, and the results of using a conventional zeolite molecular sieve as a background experiment show that the content of isomer impurities 1,1,1,3,3, 3-hexafluoropropane and 1,1,2,2,3, 3-hexafluoropropane in 1,1,1,3, 3-hexafluoropropane are consistent between the raw material and the product, and comparative examples 1 to 6 show that the conventional zeolite molecular sieve has no effect, and the catalyst with platinum as an active center has good isomer separation performance.
The purity of the hexafluoropropane in examples 1 to 6 was 99.996%, and the purity of the hexafluoropropane in examples 4 and 5 was 99.998%, which indicates that the purification method of the present invention can significantly improve the purity of the hexafluoropropane. Compared with the example 5, the effect of the example 4 is higher than that of the examples 1 to 3, mainly because the content of active center platinum is higher, the catalytic temperature is more proper, the catalytic rearrangement characteristic is better, and the isomer can be effectively removed.
The method has high production efficiency, high directional purification depth and stable process performance, and can finally obtain the electronic grade hexafluoropropane with the purity of more than 99.996 percent and meet the requirements of advanced semiconductor processing.
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, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A method for separating high-purity electronic grade hexafluoropropane isomeride is characterized by comprising the following steps: the method comprises the following steps: s1: washing with water to remove acid: introducing a hexafluoropropane raw material to be purified into a water washing tower for water washing to remove acid; s2: adsorption and dehydration: introducing the washed raw materials into an adsorption tower for dehydration; s3: catalytic conversion of the isomers 1,1,1,2,3, 3-hexafluoropropane and 1,1,2,2,3, 3-hexafluoropropane to the designated structures 1,1,1,3,3, 3-hexafluoropropane; s4: rectifying to remove light component impurities and heavy component impurities; wherein, in step S3, a catalytic converter is used, which is in the form of a fixed bed reactor, wherein the active center of the catalyst packed is platinum with a loading of 0.2-0.8 wt%.
2. The process of claim 1 for the separation of high purity electronic grade hexafluoropropane isomers, wherein: the loading of the catalyst is 0.5-0.8 wt%.
3. The process of claim 1 for the separation of high purity electronic grade hexafluoropropane isomers, wherein: the carrier of the catalyst used in the step S3 is an inert material containing aluminum, and the ratio of the carrier to the silicon to the aluminum is 5-10.
4. The process of claim 3, wherein the separation of the high purity electronic grade hexafluoropropane isomers is carried out by: the carrier in the catalytic conversion tower is alumina, aluminum boehmite or zeolite molecular sieve.
5. The process of claim 1 for the separation of high purity electronic grade hexafluoropropane isomers, wherein: the specific surface area of the catalyst in the step S3 is 200-500m2/g。
6. The process of claim 1 for the separation of high purity electronic grade hexafluoropropane isomers, wherein: the gas space velocity of the catalytic conversion tower in the step S3 is 50-200h-1。
7. The process of claim 1 for the separation of high purity electronic grade hexafluoropropane isomers, wherein: the catalytic conversion temperature in the step S3 is 400-600 ℃.
8. The process of claim 1 for the separation of high purity electronic grade hexafluoropropane isomers, wherein: the catalytic conversion temperature in the step S3 is 450-500 ℃.
9. The process for the separation of high purity electronic grade hexafluoropropane isomers according to claim 1, wherein: the catalytic conversion pressure in the step S3 is 0.1-0.3 MPa.
10. The process of claim 1 for the separation of high purity electronic grade hexafluoropropane isomers, wherein: the rectifying tower system in the step S4 comprises a light component impurity removal rectifying tower and a heavy component impurity removal rectifying tower, wherein the light component impurity removal rectifying tower and the heavy component impurity removal rectifying tower respectively remove light component impurities, the process conditions of the two towers are that the tower pressure is 0.1-1.0MPa, and the tower top and the tower bottom operating temperature is-20 ℃ to 40 ℃.
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