CN117105971A - Method for purifying tetramethylsilane - Google Patents
Method for purifying tetramethylsilane Download PDFInfo
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- CN117105971A CN117105971A CN202311081158.1A CN202311081158A CN117105971A CN 117105971 A CN117105971 A CN 117105971A CN 202311081158 A CN202311081158 A CN 202311081158A CN 117105971 A CN117105971 A CN 117105971A
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- Prior art keywords
- tetramethylsilane
- purifying
- product
- crude
- isopentene
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- CZDYPVPMEAXLPK-UHFFFAOYSA-N tetramethylsilane Chemical compound C[Si](C)(C)C CZDYPVPMEAXLPK-UHFFFAOYSA-N 0.000 title claims abstract description 128
- 238000000034 method Methods 0.000 title claims abstract description 47
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 claims abstract description 78
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 claims abstract description 39
- 239000013067 intermediate product Substances 0.000 claims abstract description 31
- YHQXBTXEYZIYOV-UHFFFAOYSA-N 3-methylbut-1-ene Chemical compound CC(C)C=C YHQXBTXEYZIYOV-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000003054 catalyst Substances 0.000 claims abstract description 28
- 239000000047 product Substances 0.000 claims abstract description 26
- 238000000746 purification Methods 0.000 claims abstract description 24
- 239000002994 raw material Substances 0.000 claims abstract description 21
- 238000006555 catalytic reaction Methods 0.000 claims abstract description 19
- 239000012043 crude product Substances 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 238000002156 mixing Methods 0.000 claims abstract description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 20
- 239000000126 substance Substances 0.000 claims description 17
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 15
- 239000002808 molecular sieve Substances 0.000 claims description 14
- 238000009833 condensation Methods 0.000 claims description 10
- 230000005494 condensation Effects 0.000 claims description 10
- 229910052697 platinum Inorganic materials 0.000 claims description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- 230000015572 biosynthetic process Effects 0.000 claims description 8
- YGZSVWMBUCGDCV-UHFFFAOYSA-N chloro(methyl)silane Chemical compound C[SiH2]Cl YGZSVWMBUCGDCV-UHFFFAOYSA-N 0.000 claims description 8
- 238000003786 synthesis reaction Methods 0.000 claims description 8
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 239000006227 byproduct Substances 0.000 claims description 3
- 239000012535 impurity Substances 0.000 abstract description 27
- 238000009835 boiling Methods 0.000 abstract description 22
- 230000009471 action Effects 0.000 abstract description 3
- 238000006243 chemical reaction Methods 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- 230000008569 process Effects 0.000 description 10
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 6
- 229910000077 silane Inorganic materials 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 230000003213 activating effect Effects 0.000 description 4
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 4
- IJOOHPMOJXWVHK-UHFFFAOYSA-N chlorotrimethylsilane Chemical compound C[Si](C)(C)Cl IJOOHPMOJXWVHK-UHFFFAOYSA-N 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 238000004821 distillation Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- KTQYJQFGNYHXMB-UHFFFAOYSA-N dichloro(methyl)silicon Chemical compound C[Si](Cl)Cl KTQYJQFGNYHXMB-UHFFFAOYSA-N 0.000 description 2
- LIKFHECYJZWXFJ-UHFFFAOYSA-N dimethyldichlorosilane Chemical group C[Si](C)(Cl)Cl LIKFHECYJZWXFJ-UHFFFAOYSA-N 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229940050176 methyl chloride Drugs 0.000 description 2
- 239000005055 methyl trichlorosilane Substances 0.000 description 2
- 239000005048 methyldichlorosilane Substances 0.000 description 2
- JLUFWMXJHAVVNN-UHFFFAOYSA-N methyltrichlorosilane Chemical compound C[Si](Cl)(Cl)Cl JLUFWMXJHAVVNN-UHFFFAOYSA-N 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000011863 silicon-based powder Substances 0.000 description 2
- 239000005051 trimethylchlorosilane Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000011344 liquid material Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 238000001577 simple distillation Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/20—Purification, separation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
Abstract
The invention discloses a method for purifying tetramethylsilane, which comprises the following steps: s1, pre-purifying a tetramethylsilane raw material to obtain a tetramethylsilane crude product; s2, mixing the crude tetramethylsilane product with a catalyst, heating, and performing a catalytic reaction to convert isopentane in the crude tetramethylsilane product into isopentene to obtain an intermediate product; s3, rectifying the intermediate product to remove isopentene in the intermediate product, and obtaining purified tetramethylsilane. According to the purification method of the tetramethylsilane, most of easily separated impurities in the tetramethylsilane raw material are removed through pre-purification treatment, and then the crude tetramethylsilane is mixed with a catalyst, so that isopentane impurities which are difficult to separate are converted into isopentene through catalytic reaction under the action of the catalyst, the boiling point difference between the isopentene and the tetramethylsilane is large, and therefore the isopentene is removed through rectification after that, and finally the purified tetramethylsilane is obtained.
Description
Technical Field
The invention relates to the technical field of purification processes of tetramethylsilane, in particular to a purification method of tetramethylsilane.
Background
Tetramethylsilane, abbreviated as 4MS or TMS, is an important organic silicon material and has wide application in the fields of medicine, aerospace building, mechanical materials and the like. The ultra-high purity (mass fraction is greater than or equal to 99.99%) 4MS can be used as a precursor for Chemical Vapor Deposition (CVD) or Plasma Enhanced Chemical Vapor Deposition (PECVD) in the electronics industry for preparing high quality silicon carbide films.
Industrially, methyl chlorosilane is synthesized by a direct method under the catalysis of copper by methyl chloride and silicon powder. In the synthesis process of the direct method, the main product is dimethyl dichlorosilane, which accounts for more than 80 percent of the total amount, and simultaneously, a large amount of methyl chlorosilane mixture is generated, including methyl trichlorosilane, trimethyl chlorosilane, methyl dichlorosilane, low boiling point silane mixture (short for low boiling point substances, LBR), high boiling point silane mixture (short for high boiling point substances, HBR) and the like. The low boiling point substances contain about 40% of 4MS, and the method for enriching and purifying the low boiling point mixture constitutes the main preparation method of 4MS at present. The method has higher economic value, and if the purification method is adopted for enrichment and purification, the low-boiling-point substance dangerous waste discharge of enterprises can be effectively reduced, and the enterprise benefit can be increased. However, the method increases the difficulty of purifying the tetramethylsilane from the low-boiling-point substances because the impurities generated by synthesis are more and the isopentane (boiling point 30 ℃) which has the boiling point similar to that of the target product 4MS (26-28 ℃) exists.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.
Disclosure of Invention
The invention aims to provide a purification method of tetramethylsilane, which can effectively reduce the content of isopentane impurities in tetramethylsilane raw materials.
To achieve the above object, an embodiment of the present invention provides a method for purifying tetramethylsilane, comprising the steps of:
s1, pre-purifying a tetramethylsilane raw material to obtain a tetramethylsilane crude product;
s2, mixing the crude tetramethylsilane product with a catalyst, heating, and performing a catalytic reaction to convert isopentane in the crude tetramethylsilane product into isopentene to obtain an intermediate product;
s3, rectifying the intermediate product to remove isopentene in the intermediate product, and obtaining purified tetramethylsilane.
In one or more embodiments of the invention, the catalyst is a platinum modified ZSM-5 molecular sieve or a platinum modified 5A molecular sieve.
In one or more embodiments of the present invention, the catalyst in the step S2 is activated with nitrogen at 500 to 600 ℃ and then activated with hydrogen before being mixed with the crude tetramethylsilane.
In one or more embodiments of the present invention, the heating temperature in the step S2 is 500 to 600 ℃.
In one or more embodiments of the present invention, the step S2 further includes: and collecting the substances after the catalytic reaction by adopting a condensation treatment mode.
In one or more embodiments of the invention, the temperature of the condensing treatment is 20 to 25 ℃.
In one or more embodiments of the present invention, the pre-purification process in step S1 is a rectification process.
In one or more embodiments of the invention, the rectification process is a single column rectification process or a double column rectification process.
In one or more embodiments of the present invention, the step S2 specifically includes:
and placing a catalyst in a fixed bed reactor, introducing the crude tetramethylsilane product into the fixed bed reactor, heating, and performing catalytic reaction to convert isopentane in the crude tetramethylsilane product into isopentene, thereby obtaining an intermediate product.
In one or more embodiments of the invention, the tetramethylsilane feed is from a byproduct of the direct process synthesis of methylchlorosilanes.
Compared with the prior art, according to the purification method of the tetramethylsilane, most of easily separated impurities in the tetramethylsilane raw material are removed through pre-purification treatment, and then the crude tetramethylsilane is mixed with a catalyst, so that isopentane impurities which are difficult to separate are converted into isopentene through catalytic reaction under the action of the catalyst, the boiling point difference between the isopentene and the tetramethylsilane is larger, and therefore the isopentene is removed through rectification, and finally the purified tetramethylsilane is obtained.
Drawings
Fig. 1 is a flow chart of a method for purifying tetramethylsilane according to one embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the invention is, therefore, to be taken in conjunction with the accompanying drawings, and it is to be understood that the scope of the invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.
Industrially, methyl chlorosilane is synthesized by a direct method under the catalysis of copper by methyl chloride and silicon powder. In the synthesis process of the direct method, the main product is dimethyl dichlorosilane, which accounts for more than 80 percent of the total amount, and simultaneously, a large amount of methyl chlorosilane mixture is generated, including methyl trichlorosilane, trimethyl chlorosilane, methyl dichlorosilane, low boiling point silane mixture (short for low boiling point substances, LBR), high boiling point silane mixture (short for high boiling point substances, HBR) and the like. The low boiling point substances contain about 40% of 4MS, and the method for enriching and purifying the low boiling point mixture constitutes the main preparation method of 4MS at present. The method has higher economic value, and if the purification method is adopted for enrichment and purification, the low-boiling-point substance dangerous waste discharge of enterprises can be effectively reduced, and the enterprise benefit can be increased. However, the method has the advantages that the impurities generated by synthesis are more, and the isopentane with the boiling point (the boiling point is 30 ℃) which is similar to that of the target product 4MS (26-28 ℃) exists, so that the isopentane and the tetramethylsilane are difficult to separate by simple distillation or rectification treatment.
Thus, as shown in fig. 1, the purification method of tetramethylsilane according to the preferred embodiment of the present invention comprises the steps of:
s1, pre-purifying the tetramethylsilane raw material to obtain a tetramethylsilane crude product.
It will be appreciated that the purification process of the present invention is useful for purifying a tetramethylsilane feed, which may be considered to include tetramethylsilane (target product) as well as isopentane (impurity), to give a relatively high purity tetramethylsilane. Of course, the tetramethylsilane feedstock may also include other impurities.
In one embodiment, the tetramethylsilane starting material is derived from a byproduct of the direct synthesis of methylchlorosilanes; specifically, the tetramethylsilane raw material is mainly a low boiling point silane mixture from direct synthesis of methylchlorosilane. Thus, it contains not only tetramethylsilane and isopentane, but also other impurities.
In one embodiment, the pre-purification treatment in step S1 is a rectification treatment. The method mainly plays a role in removing most of easily separated impurities in the tetramethylsilane raw material by a rectification treatment mode. The easily separable impurities can be considered to have a boiling point that differs significantly from that of tetramethylsilane and can be easily removed by distillation.
Specifically, the rectification treatment is single-tower rectification treatment or double-tower rectification treatment.
When the rectification treatment is single-tower rectification treatment, namely, the single-tower rectification tower is adopted to carry out rectification treatment on the tetramethylsilane raw material, wherein heavy component impurities are discharged from the bottom of the tower, light component impurities are discharged from the top of the tower, and substances collected in the middle of the tower are the tetramethylsilane crude product.
When the rectification treatment is double-tower rectification treatment, namely, the light component removing rectifying tower and the heavy component removing rectifying tower which are arranged in series are adopted to carry out rectification treatment on the tetramethylsilane raw material, wherein heavy component impurities are discharged from the bottom of the heavy component removing rectifying tower, light component impurities are discharged from the top of the light component removing rectifying tower, and substances collected from the top of the heavy component removing rectifying tower are crude tetramethylsilane products.
In other embodiments, the pre-purification treatment may also be a distillation treatment; or, the tetramethylsilane raw material is subjected to hydrolysis treatment and then is subjected to distillation or rectification treatment. So long as the most of the easily separable impurities in the tetramethylsilane raw material can be removed. In addition, this step is also intended to prevent other impurities from reacting with the catalyst, thereby affecting the conversion of isopentane reaction to isopentene.
S2, mixing the crude tetramethylsilane product with a catalyst, heating, and performing a catalytic reaction to convert isopentane in the crude tetramethylsilane product into isopentene, thereby obtaining an intermediate product.
In a specific embodiment, the catalyst is a platinum modified ZSM-5 molecular sieve or a platinum modified 5A molecular sieve. Isopentane enters a molecular sieve and then undergoes a catalytic reaction to be converted into isopentene. In addition, when the catalyst selects the modified molecular sieve, the pre-purification treatment can remove easily-separated impurities, so that the problems that the impurities and isopentane enter a molecular sieve bed together to block a molecular sieve pore channel or occupy an active catalytic point, so that isopentane cannot be reacted to be converted into isopentene or the reaction efficiency is too low are avoided. In other words, the pre-purification treatment may increase the molecular sieve catalytic efficiency. .
Specifically, before the catalyst is mixed with the crude tetramethylsilane product in the step S2, nitrogen is used for activating treatment at 500-600 ℃ and then hydrogen is used for activating treatment. Nitrogen is used for activating to replace impurities in a catalyst bed and a non-reaction system inside the catalyst, and hydrogen is used for activating to change active components of the catalyst into simple substance metal state, so that deep reduction of the metal components is ensured.
Specifically, the heating temperature in step S2 is 500-600 ℃.
Specifically, the step S2 further includes: and collecting the substances after the catalytic reaction by adopting a condensation treatment mode. The condensation treatment is used for collecting liquid materials and facilitating the treatment of the next rectification process with the temperature lower than the catalytic reaction temperature.
Wherein the temperature of the condensation treatment is 20-25 ℃. The condensation process may be a continuous process, starting from the beginning of the catalytic reaction and ending with the end of the catalytic reaction.
In a specific implementation process, the step S2 specifically includes:
and placing a catalyst in a fixed bed reactor, introducing the crude tetramethylsilane product into the fixed bed reactor, heating, and performing catalytic reaction to convert isopentane in the crude tetramethylsilane product into isopentene, thereby obtaining an intermediate product.
The reaction equation for the conversion of isopentane to isopentene is:
s3, rectifying the intermediate product to remove isopentene in the intermediate product, and obtaining purified tetramethylsilane.
Specifically, the rectification treatment is single-tower rectification treatment or double-tower rectification treatment.
When the rectification treatment is single-tower rectification treatment, namely, the intermediate product is rectified by adopting a single-tower rectification tower, wherein heavy component impurities are discharged from the bottom of the tower, light component impurities are discharged from the top of the tower, and substances collected in the middle of the tower are purified tetramethylsilane.
When the rectification treatment is double-tower rectification treatment, namely, rectification treatment is carried out on intermediate products by adopting a light-removal rectifying tower and a heavy-removal rectifying tower which are arranged in series, wherein heavy component impurities are discharged from the bottom of the heavy-removal rectifying tower, light component impurities are discharged from the top of the light-removal rectifying tower, and substances collected from the top of the heavy-removal rectifying tower are purified tetramethylsilane.
The purification method of tetramethylsilane according to the present invention will be described in detail with reference to specific examples.
The following examples and comparative examples each use a low boiling point silane mixture containing 47% tetramethylsilane and 23% isopentane as the tetramethylsilane feed.
Example 1
S1, rectifying a tetramethylsilane raw material in a double tower to obtain a tetramethylsilane crude product, wherein the tetramethylsilane content is 62% and the isopentane content is 31%.
S2, introducing the crude tetramethylsilane product into a fixed bed reactor, wherein the reaction temperature is 500 ℃, using a platinum modified 5A molecular sieve as a catalyst, and collecting the reacted material by adopting a condensation treatment mode to obtain an intermediate product, wherein the isopentane content in the intermediate product is 14% and the isopentene content is 17%.
S3, rectifying the intermediate product by a double tower to obtain purified tetramethylsilane, wherein the content of isopentane is 10% and the content of tetramethylsilane is 87%.
Example 2
S1, rectifying a tetramethylsilane raw material in a double tower to obtain a tetramethylsilane crude product, wherein the tetramethylsilane content is 62% and the isopentane content is 31%.
S2, introducing the crude tetramethylsilane product into a fixed bed reactor, wherein the reaction temperature is 550 ℃, a platinum modified 5A molecular sieve is used as a catalyst, and collecting the reacted material in a condensation treatment mode to obtain an intermediate product, wherein the isopentane content in the intermediate product is 9% and the isopentene content in the intermediate product is 22%.
S3, rectifying the intermediate product by a double tower to obtain purified tetramethylsilane, wherein the isopentane content is 6% and the tetramethylsilane content is 91%.
Example 3
S1, rectifying a tetramethylsilane raw material in a double tower to obtain a tetramethylsilane crude product, wherein the tetramethylsilane content is 62% and the isopentane content is 31%.
S2, introducing the crude tetramethylsilane product into a fixed bed reactor, wherein the reaction temperature is 500 ℃, using a platinum modified ZSM-5 molecular sieve as a catalyst, and collecting the reacted material by adopting a condensation treatment mode to obtain an intermediate product, wherein the isopentane content in the intermediate product is 7%, and the isopentene content in the intermediate product is 24%.
S3, rectifying the intermediate product by a double tower to obtain purified tetramethylsilane, wherein the content of isopentane is 4%, and the content of tetramethylsilane is 93%.
Example 4
S1, rectifying a tetramethylsilane raw material in a double tower to obtain a tetramethylsilane crude product, wherein the tetramethylsilane content is 62% and the isopentane content is 31%.
S2, introducing the crude tetramethylsilane product into a fixed bed reactor, wherein the reaction temperature is 550 ℃, using a platinum modified ZSM-5 molecular sieve as a catalyst, and collecting the reacted material by adopting a condensation treatment mode to obtain an intermediate product, wherein the isopentane content in the intermediate product is 2% and the isopentene content is 29%.
S3, rectifying the intermediate product by a double tower to obtain purified tetramethylsilane, wherein the isopentane content is 1% and the tetramethylsilane content is 96%.
Comparative example 1
S1, rectifying a tetramethylsilane raw material in a double tower to obtain a tetramethylsilane crude product, wherein the tetramethylsilane content is 62% and the isopentane content is 31%.
S2, rectifying the crude tetramethylsilane product by a double tower to obtain purified tetramethylsilane, wherein the content of isopentane is 29%, the content of tetramethylsilane is 69%, and the content of isopentene is 0%.
As can be seen from the procedural data of comparative example 1: although the content of isopentane can be reduced by simple multiple rectification, the amount of reduction is limited. As can be seen from the comparison of the procedural data of example 1 with the procedural data of comparative example 1, the purity of tetramethylsilane in the purified tetramethylsilane of example 1 is higher than that of tetramethylsilane in the purified tetramethylsilane of comparative example 1, and the purification method of tetramethylsilane of the present invention can effectively remove isopentane in the tetramethylsilane raw material.
From the procedural data of examples 1 to 4, it can be seen that the purification method of tetramethylsilane according to the present invention can greatly reduce the content of isopentane, thereby obtaining tetramethylsilane with higher purity.
In summary, according to the purification method of tetramethylsilane in the embodiment of the invention, most of the easily separable impurities in the tetramethylsilane raw material are removed through pre-purification treatment, and then the crude tetramethylsilane is mixed with a catalyst, so that isopentane impurities which are difficult to separate are converted into isopentene through catalytic reaction under the action of the catalyst, and the boiling points of the isopentene and the tetramethylsilane are greatly different, so that the isopentene is removed through rectification, and the purified tetramethylsilane is finally obtained.
The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application to thereby enable one skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. A method for purifying tetramethylsilane, comprising the steps of:
s1, pre-purifying a tetramethylsilane raw material to obtain a tetramethylsilane crude product;
s2, mixing the crude tetramethylsilane product with a catalyst, heating, and performing a catalytic reaction to convert isopentane in the crude tetramethylsilane product into isopentene to obtain an intermediate product;
s3, rectifying the intermediate product to remove isopentene in the intermediate product, and obtaining purified tetramethylsilane.
2. The method for purifying tetramethylsilane according to claim 1, wherein said catalyst is a platinum modified ZSM-5 molecular sieve or a platinum modified 5A molecular sieve.
3. The method for purifying tetramethylsilane according to claim 2, wherein said catalyst in said step S2 is activated with nitrogen at 500 to 600 ℃ and then with hydrogen before being mixed with said crude tetramethylsilane.
4. The method for purifying tetramethylsilane according to claim 1, wherein the heating temperature in said step S2 is 500 to 600 ℃.
5. The method for purifying tetramethylsilane according to claim 1, wherein said step S2 further comprises: and collecting the substances after the catalytic reaction by adopting a condensation treatment mode.
6. The method for purifying tetramethylsilane according to claim 5, wherein the condensing temperature is 20 to 25 ℃.
7. The method for purifying tetramethylsilane according to claim 1, wherein the pre-purification treatment in step S1 is a rectification treatment.
8. The method for purifying tetramethylsilane according to claim 1 or 7, wherein said rectification treatment is a single-column rectification treatment or a double-column rectification treatment.
9. The method for purifying tetramethylsilane according to claim 1, wherein said step S2 is specifically:
and placing a catalyst in a fixed bed reactor, introducing the crude tetramethylsilane product into the fixed bed reactor, heating, and performing catalytic reaction to convert isopentane in the crude tetramethylsilane product into isopentene, thereby obtaining an intermediate product.
10. The method for purifying tetramethylsilane according to claim 1, wherein said tetramethylsilane raw material is derived from a byproduct of direct synthesis of methylchlorosilane.
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| CN202311081158.1A CN117105971A (en) | 2023-08-25 | 2023-08-25 | Method for purifying tetramethylsilane |
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