CN115536687B - Process for preparing trialkylaminosilanes and use thereof - Google Patents

Process for preparing trialkylaminosilanes and use thereof Download PDF

Info

Publication number
CN115536687B
CN115536687B CN202211178566.4A CN202211178566A CN115536687B CN 115536687 B CN115536687 B CN 115536687B CN 202211178566 A CN202211178566 A CN 202211178566A CN 115536687 B CN115536687 B CN 115536687B
Authority
CN
China
Prior art keywords
bis
reaction
pressure
silane
monosilane
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202211178566.4A
Other languages
Chinese (zh)
Other versions
CN115536687A (en
Inventor
鲁铮
王忠英
赵彬驭
蔡崇玄
周晓兵
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiangsu Nata Opto Electronic Material Co Ltd
Original Assignee
Jiangsu Nata Opto Electronic Material Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiangsu Nata Opto Electronic Material Co Ltd filed Critical Jiangsu Nata Opto Electronic Material Co Ltd
Priority to CN202211178566.4A priority Critical patent/CN115536687B/en
Publication of CN115536687A publication Critical patent/CN115536687A/en
Application granted granted Critical
Publication of CN115536687B publication Critical patent/CN115536687B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

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
    • C07F7/025—Silicon compounds without C-silicon linkages
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)

Abstract

The invention discloses a preparation method and application of trialkyl amino silane. The preparation method comprises the following steps: placing an amine source and a catalyst in a sealed reaction vessel, introducing monosilane into the sealed reaction vessel in a backpressure or pressure-holding manner, and reacting at 40-80 ℃ to prepare trialkyl aminosilane; wherein the catalyst comprises any one of dibutyl magnesium, bis (trimethylsilyl) amino potassium, bis (hexamethyldisilazide) calcium and bis (hexamethyldisilazide) strontium; the molar ratio of the monosilane to the amine source is 1. The method provided by the invention is a one-step reaction, and a large amount of solid is not formed in the reaction process, so that the space utilization rate is high.

Description

Process for preparing trialkylaminosilanes and use thereof
Technical Field
The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method and application of trialkyl aminosilane.
Background
Trialkylaminosilanes are commonly used as starting materials (precursors) for the production of silicon-based semiconductor thin film materials, such as silicon oxide, silicon nitride, and silicon carbide, by conventional vapor deposition methods and more precisely controlled atomic layer deposition methods. These silicon-based semiconductor thin film materials have been used in the field of manufacturing high-end capacitors, solar cells, memory devices, lasers, light emitting diodes, and gas sensors.
Currently, alkyl aminosilanes can be prepared by conventional chlorosilane amination reactions. For example: JPWO2016152226A1 produces an alkyl aminosilane by direct reaction of a chlorosilane and a dialkylamine with a large amount of by-product hydrochloride formation in addition to the target product. The method needs an additional filtering step to obtain a target product, and a small amount of hydrochloride is dissolved in the product and needs to be separated at a later stage, so that the product contains chlorine impurities; patent CN107365416A proposes a method for preparing side chain modified polysiloxane, through dichlorosilane and organic solvent mixing, then add acrylic acid, allyl alcohol or allylamine into this mixed solution, decompress and distill and remove the organic solvent after the reaction is finished, get chlorosilane substitution product; adding a chlorosilane substitution product and a catalyst into a solvent for reaction, and removing the organic solvent by reduced pressure distillation to obtain a hydrosilylation product; then, the hydrosilylation product and bifunctional alkoxy silane or chlorosilane are subjected to cohydrolysis, and a proper amount of end capping agent is added to prepare the side chain modified polysiloxane. In the invention, the raw materials are cheap and easy to obtain, the product yield is high, but the operation steps are excessive, and the product contains chlorine impurities. In the methods disclosed in the prior patents and documents, a large amount of solid byproduct hydrochloride is formed in the reaction process, a large amount of solvent is required for the reaction, the volume efficiency is reduced, and the product contains chlorine impurities. In order to solve the above technical problems, it is an urgent need to provide a simple and efficient method for preparing polyamino silane.
Disclosure of Invention
The main object of the present invention is to provide a preparation method and use of trialkyl aminosilane to overcome the disadvantages of the prior art.
In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:
the embodiment of the invention provides a preparation method of trialkyl aminosilane, which comprises the following steps:
placing an amine source and a catalyst in a sealed reaction container, introducing monosilane into the sealed reaction container in a back pressure or pressure-holding mode, and reacting at 40-80 ℃ to prepare trialkyl aminosilane;
wherein the catalyst comprises any one of dibutyl magnesium, bis (trimethylsilyl) amino potassium, bis (hexamethyldisilazide) calcium and bis (hexamethyldisilazide) strontium; the molar ratio of the monosilane to the amine source is 1.
In some more specific embodiments, the trialkylaminosilane comprises tris (diethylamino) silane (SiH [ N (CH) 2 CH 3 ) 2 ] 3 ) Tris (tert-butylamino) silane (SiH [ NH (C) ] 4 H 9 )] 3 ) Tris (N-propylamino) silane (SiH [ N (CH) ] 2 CH 2 CH 3 ) 2 ] 3 ) Any one of them.
The embodiment of the invention also provides a method for preparing the silicon-based semiconductor film material, which comprises the following steps:
preparing a trialkylaminosilane by the method described above;
and preparing the silicon-based semiconductor film material by using the trialkyl amino silane.
Compared with the prior art, the invention has the beneficial effects that:
(1) In the reaction process of trialkyl amino silane in the prior art, a large amount of solid salts are formed, the utilization rate of the reaction volume is low, and an additional separation step is needed; in the reaction process of the invention, a large amount of solid is not formed, the space utilization rate is high, and the product can be directly obtained;
(2) When bis (trimethylsilyl) amino potassium, bis (hexamethyldisilazide) calcium and bis (hexamethyldisilazide) strontium are used as catalysts, the used catalysts, raw materials and generated products are chlorine-free materials, and chlorine pollution is avoided;
(3) The preparation method of the trialkyl amino silane provided by the invention is a one-step reaction, and simultaneously, reactants can be completely converted at room temperature, and the yield of the trialkyl amino silane reaches up to 79.6%.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a mass spectrum of tris (tert-butylamino) silane prepared in example 2 of the present invention.
Detailed Description
In view of the defects of the prior art, the inventor of the present invention has long studied and largely practiced to propose the technical solution of the present invention, which will be clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Specifically, as one aspect of the technical scheme of the invention, the preparation method of the trialkyl aminosilane comprises the following steps:
placing an amine source and a catalyst in a sealed reaction container, introducing monosilane into the sealed reaction container in a back pressure or pressure-holding mode, and reacting at 40-80 ℃ to prepare trialkyl aminosilane;
wherein the catalyst comprises any one of dibutyl magnesium, bis (trimethylsilyl) amino potassium, bis (hexamethyldisilazide) calcium and bis (hexamethyldisilazide) strontium; the molar ratio of the monosilane to the amine source is 1.
In some preferred embodiments, the amine source includes diethylamine, tert-butylamine, or di-n-propylamine, and is not limited thereto.
In some preferred embodiments, the catalyst comprises any one of bis (trimethylsilyl) amino potassium, bis (hexamethyldisilazide) calcium and bis (hexamethyldisilazide) strontium, and when the catalyst is adopted, the raw materials used in the invention and the generated product are chlorine-free materials and have no chlorine pollution.
The whole preparation process of the catalyst in the invention is at room temperature, does not need heating or cooling, and is operated in an anhydrous and oxygen-free environment.
Specifically, the method for synthesizing the bis (hexamethyldisilazide) calcium comprises the following steps:
(1) 2 parts (by mass) of bis (trimethylsilyl) amino potassium obtained by weighing are poured into a three-neck flask filled with 36 parts of diethyl ether;
(2) Pouring 1.5 parts of calcium iodide into the three-neck flask while starting stirring, and keeping stirring for 48 hours;
(3) And after stirring is stopped, separating a solid-liquid mixture, pouring the obtained supernatant into an open container, waiting for natural volatilization of the supernatant, and collecting the obtained solid, namely the calcium bis (hexamethyldisilazide).
Specifically, the method for synthesizing the bis (hexamethyldisilazide) strontium comprises the following steps:
(1) Pouring 2 parts (by mass) of bis (trimethylsilyl) amino potassium obtained by weighing into a three-neck flask filled with 36 parts of diethyl ether;
(2) Pouring 1.7 parts of strontium iodide into the three-neck flask while starting stirring, and keeping stirring for 48 hours;
(3) And after stirring is stopped, separating a solid-liquid mixture, pouring the obtained supernatant into an open container, waiting for natural volatilization of the supernatant, and collecting the obtained solid, namely the bis (hexamethyldisilazide) strontium.
Specifically, the synthesis method of the bis (trimethylsilyl) amino potassium catalyst comprises the following steps: in a glove box, 1 part of metallic potassium (mass fraction) was added to 5 parts of anhydrous tetrahydrofuran. Then slowly adding a mixture of styrene (3 parts)/hexamethyldisilazane (8 parts) into the mixture, and obtaining the bis (trimethylsilyl) amino potassium catalyst after the reaction is finished when the metal potassium is completely dissolved.
In some preferred embodiments, the trialkylaminosilane includes tris (diethylamino) silane (SiH [ N (CH) 2 CH 3 ) 2 ] 3 ) Tris (tert-butylamino) silane (SiH [ NH (C) ] 4 H 9 )] 3 ) Tris (N-propylamino) silane (SiH [ N (CH) ] 2 CH 2 CH 3 ) 2 ] 3 ) And is not limited thereto.
In some preferred embodiments, the mass ratio of the catalyst to the amine source is from 0.01 to 0.05.
In some preferred embodiments, the preparation method specifically comprises: and introducing the monosilane into the sealed reaction container in a pressure-building mode, carrying out the reaction, and finishing the reaction when the pressure in the sealed reaction container does not rise any more.
In some preferred embodiments, the preparation method specifically comprises: introducing monosilane into the sealed reaction container in a backpressure mode, carrying out the reaction, keeping the pressure in the sealed reaction container unchanged through a backpressure regulating valve in the reaction process, and finishing the reaction when the introduction amount of the monosilane in the sealed reaction container reaches a specified value.
Specifically, in the implementation process of the invention, after the amine and the catalyst are added, the monosilane is introduced to the specified pressure at one time, and the reaction is carried out under the closed condition until the reaction is finished, which is called as a pressure-building reaction mode.
In the implementation process of the invention, after amine and catalyst are added, the pressure relief pressure of a back pressure valve at a gas outlet of a reaction kettle is adjusted to a specified value, then silane is continuously introduced into the reaction kettle, and when the pressure of the reaction kettle reaches the value adjusted by the back pressure valve, the pressure of the reaction kettle is relieved through the back pressure valve. In this way, monosilane is continuously fed into the reaction kettle during the reaction process, but the pressure is always kept at the specified pressure relief value of the backpressure valve, and the process is called as a backpressure reaction mode.
In some preferred embodiments, the water content of the amine source is less than or equal to 300ppm.
In some more specific embodiments, the process for preparing the trialkylaminosilane comprises:
(1) Adopting diethylamine, tert-butylamine or di-n-propylamine with the water content not higher than 300ppm as a raw material;
(2) Adding diethylamine, tert-butylamine or di-n-propylamine and a catalyst into a closed stainless steel reaction kettle, and then introducing monosilane into the reaction kettle;
(3) Introducing monosilane into the reaction kettle in a back pressure and/or pressure-holding mode, and controlling the pressure between 1bar and 15bar; hydrogen is released during the reaction. If the pressure is held back, the pressure is increased to 2 to 2.5 times of the initial pressure, and when the pressure is not increased any more, the pressure in the reaction kettle can be released to the normal pressure; if the reaction is under the back pressure condition, the reaction is finished when the introduction amount of the monosilane reaches a specified value. The catalyst comprises dibutyl magnesium (Mg (C) 4 H 9 ) 2 ) Bis (trimethylsilyl) amino potassium (KN ((CH) 3 ) 3 Si) 2 ) Bis (hexamethyldisilazide) calcium (Ca (N ((CH)) 3 ) 3 Si) 2 ) 2 ) Or bis (hexamethyldisilazide) strontium (Sr (N ((CH) 3 ) 3 Si) 2 ) 2 )；
(4) Discharging from the bottom of the reaction kettle to obtain the tri (diethylamino) silane, the tri (tertiary butylamino) silane or the tri (n-propylamino) silane.
Another aspect of the embodiments of the present invention also provides a method for preparing a silicon-based semiconductor thin film material, which includes:
preparing a trialkylaminosilane by the method described above;
and preparing the silicon-based semiconductor film material by using the trialkyl amino silane.
The technical solution of the present invention is further described in detail with reference to several preferred embodiments, which are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are given, but the scope of the present invention is not limited to the following embodiments.
The experimental materials used in the examples used below were all available from conventional biochemical reagents companies, unless otherwise specified.
Example 1:
a method for synthesizing tris (diethylamino) silane under a pressure-building condition comprises the following steps:
1) Adding 20 ml of diethylamine into a 250 ml stainless steel reaction kettle, and controlling the reaction temperature at 80 ℃;
2) Adding a catalyst bis (trimethylsilyl) amino potassium into diethylamine, wherein the adding amount of the catalyst is 2 percent of the adding mass of the diethylamine;
3) Introducing monosilane at a speed of 5L/min under the closed condition of the reaction kettle;
4) Introducing monosilane until the pressure is 5bar, releasing hydrogen in the reaction process, and finishing the reaction when the pressure does not rise any more;
5) The product yield of the tris (diethylamino) silane is calculated to be 61.8 percent after the material is discharged from the bottom of the reaction kettle.
Example 2:
a method for synthesizing tri (tert-butylamino) silane under back pressure conditions, comprising the following steps:
1) Adding 3 liters of tert-butylamine into a 5 liter stainless steel reaction kettle, and controlling the reaction temperature at 60 ℃;
2) Adding a catalyst dibutyl magnesium into tert-butylamine, wherein the adding amount of the catalyst is 2% of the adding mass of the tert-butylamine;
3) Setting the pressure of a back pressure regulating valve at a gas phase outlet at the top of the reaction kettle at 1bar;
4) Introducing monosilane into a reaction kettle at a speed of 1L/min, and increasing the pressure of the reaction kettle to 1bar and keeping the pressure of the reaction kettle at the same pressure;
5) Under the condition, when the silane is introduced into the reactor in a molar amount which is 1/3 of the molar amount of the added tert-butylamine, the reaction is finished;
6) The product yield of the tri (tert-butylamino) silane is calculated to be 79.6 percent by discharging from the bottom of the reaction kettle.
The mass spectrum of tris (tert-butylamino) silane prepared in this example is shown in FIG. 1.
Example 3:
a method for synthesizing tri (n-propylamino) silane under a pressure building condition comprises the following steps:
1) Adding 20 ml of di-n-propylamine into a 250 ml of stainless steel reaction kettle, and controlling the reaction temperature at 60 ℃;
2) Adding a catalyst bis (trimethylsilyl) amino potassium into di-n-propylamine, wherein the adding amount of the catalyst is 2 percent of the adding mass of the di-n-propylamine;
3) Introducing monosilane into a reaction kettle at a speed of 5L/min;
4) Introducing monosilane until the pressure is 5bar, releasing hydrogen in the reaction process, and finishing the reaction when the pressure does not rise any more;
5) Discharging from the bottom of the reaction kettle, and calculating to obtain the bis (n-propylamino) silane product with the yield of 66.7%.
Example 4
A method for synthesizing tri (tert-butylamino) silane under back pressure conditions, comprising the following steps:
1) Adding 3 liters of tert-butylamine into a 5 liter stainless steel reaction kettle, and controlling the reaction temperature at 40 ℃;
2) Adding a catalyst dibutyl magnesium into tert-butylamine, wherein the adding amount of the catalyst is 5% of the adding mass of the tert-butylamine;
3) Setting the pressure of a back pressure regulating valve at a gas phase outlet at the top of the reaction kettle at 15bar;
4) Introducing monosilane into a reaction kettle at the introduction speed of 5L/min, and raising the pressure of the reaction kettle to 15bar;
5) Under the condition, when the silane is introduced into the reactor in a molar amount which is 1/3 of the molar amount of the added tert-butylamine, the reaction is finished;
6) The product yield of the tri (tert-butylamino) silane is calculated to be 61.1 percent after discharging from the bottom of the reaction kettle.
In addition, the inventors of the present invention have also made experiments with other materials, process operations, and process conditions described in the present specification with reference to the above examples, and have obtained preferable results.
It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention without departing from the spirit of the present invention and the protection scope of the claims.

Claims (10)

1. A process for preparing a trialkylaminosilane, comprising:
placing an amine source and a catalyst in a sealed reaction container, introducing the silane into the sealed reaction container in a back pressure or pressure-holding mode, and reacting at 40-80 ℃ to prepare trialkyl aminosilane;
wherein the catalyst is selected from any one of dibutyl magnesium, bis (trimethylsilyl) amino potassium, bis (hexamethyldisilazide) calcium and bis (hexamethyldisilazide) strontium; the molar ratio of the monosilane to the amine source is 1 to 5; the amine source is selected from diethylamine, tert-butylamine or di-n-propylamine.
2. The method of claim 1, wherein: the catalyst is selected from any one of bis (trimethyl silyl) amino potassium, bis (hexamethyldisilazide) calcium and bis (hexamethyldisilazide) strontium.
3. The production method according to claim 1, characterized in that: the trialkylaminosilane is selected from any one of tris (diethylamino) silane, tris (tert-butylamino) silane and tris (n-propylamino) silane.
4. The method of claim 1, wherein: the mass ratio of the catalyst to the amine source is 0.01 to 0.05.
5. The method of claim 1, wherein: the introduction rate of the monosilane is 1 to 5L/min.
6. The method of claim 1, wherein: the reaction temperature is 50 to 60 ℃, and the reaction time is 1 to 8h.
7. The method according to claim 1, comprising: introducing monosilane into the sealed reaction container in a backpressure mode, carrying out the reaction, keeping the pressure in the sealed reaction container unchanged through a backpressure regulating valve in the reaction process, and finishing the reaction when the introduction amount of the monosilane in the sealed reaction container reaches a specified value.
8. The preparation method according to claim 1, characterized by specifically comprising: and introducing the monosilane into the sealed reaction container in a pressure-building mode, carrying out the reaction, and finishing the reaction when the pressure in the sealed reaction container does not rise any more.
9. The method of claim 1, wherein: the water content in the amine source is less than or equal to 300ppm.
10. A method of preparing a silicon-based semiconductor thin film material, comprising:
preparing a trialkylaminosilane using the process of any one of claims 1-9;
and preparing the silicon-based semiconductor film material by using the trialkyl amino silane.
CN202211178566.4A 2022-09-26 2022-09-26 Process for preparing trialkylaminosilanes and use thereof Active CN115536687B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211178566.4A CN115536687B (en) 2022-09-26 2022-09-26 Process for preparing trialkylaminosilanes and use thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211178566.4A CN115536687B (en) 2022-09-26 2022-09-26 Process for preparing trialkylaminosilanes and use thereof

Publications (2)

Publication Number Publication Date
CN115536687A CN115536687A (en) 2022-12-30
CN115536687B true CN115536687B (en) 2023-04-11

Family

ID=84729178

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211178566.4A Active CN115536687B (en) 2022-09-26 2022-09-26 Process for preparing trialkylaminosilanes and use thereof

Country Status (1)

Country Link
CN (1) CN115536687B (en)

Also Published As

Publication number Publication date
CN115536687A (en) 2022-12-30

Similar Documents

Publication Publication Date Title
CN115260222B (en) Preparation method and application of dialkyl aminosilane
CN115260223B (en) Use of chlorine-free catalysts for producing diisopropylamine silanes
CN101445240B (en) Method for seperating and recovering conversion reaction gas
US20120277457A1 (en) Aminosilanes and methods for making same
JP5654490B2 (en) Recycling process of high boiling point waste
EP2004660A1 (en) Pentakis(dimethylamino) disilane precursor comprising compound and method for the preparation thereof
US20120128568A1 (en) Production of silanes from silicon alloys and alkaline earth metals or alkaline earth metal silicides
US20120165564A1 (en) Method for preparing purified aminosilane
JPS59123227A (en) Silicon accumulating method
EP2036859A2 (en) Method for producing polycrystalline silicon
CN115536687B (en) Process for preparing trialkylaminosilanes and use thereof
TWI798685B (en) Method of preparing iodosilanes and compositions therefrom
JP6014392B2 (en) Method for producing cyclohexasilanes
KR20170027824A (en) Method for purifying chlorosilane
CN112839904B (en) Synthesis of trichlorosilane from tetrachlorosilane and hydrosilane
US8551438B2 (en) Production of silanes by acid hydrolysis of alloys of silicon and of alkaline-earth metals or alkaline-earth metal silicides
EP1671977B1 (en) Process for production of trialkoxyhalosilanes and process for production of alkoxy(dialkylamino)silanes
CN115417413B (en) Preparation method and application of neopentasilane intermediate
CN102803275B (en) Method for producing organoalkoxy hydrogen silanes
CA2477622A1 (en) Preparation of mixed-halogen halo-silanes
CN1176090C (en) Process for preparing alkoxychlorosilane
JP4542209B2 (en) Method for producing polycrystalline silicon and method for producing high-purity silica
KR20170005305A (en) Process for the preparation of trisalkylaminosilane
FR2989074A1 (en) Preparing mixture of silane and germane compounds, involves reacting mixture of alloy containing silicon alloy in the form of powder and germanium alloy in the form of powder with hydrochloric acid that is pre-dissolved in aqueous solution
KR20150027905A (en) Continuous redistribution method of high-boiling point residues formed as by-products in the direct synthesis of methylchlorosilanes

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant