Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/08—Compounds containing halogen
  • C01B33/107—Halogenated silanes
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/08—Compounds containing halogen
  • C01B33/10—Compounds containing silicon, fluorine, and other elements
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/08—Compounds containing halogen
  • C01B33/107—Halogenated silanes
  • C01B33/1071—Tetrachloride, trichlorosilane or silicochloroform, dichlorosilane, monochlorosilane or mixtures thereof
• • 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
  • C07F7/12—Organo silicon halides
• • 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
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/10—Process efficiency

Definitions

• the invention relates to a process for the preparation of trichlorosilane by means of thermal hydrogenation of silicon tetrachloride.
• tetrachlorosilane (Tetra) on.
• the tetrachlorosilane can be converted by the silane conversion, a catalytic or thermal dehydrohalogenation of tetrachlorosilane with hydrogen, again to Sitri and hydrogen chloride.
• Two variants of the process are known in the art for this purpose:
• JP 60081010 (Denki Kagaku Kogyo KK / 1985) also describes a quenching process (at lower H2: tetra ratios) to increase the trichlorosilane content in the product gas.
• the object of the present invention is to provide a process for the preparation of trichlorosilane by means of thermal hydrogenation of a reactant gas containing silicon tetrachloride which enables a high yield of trichlorosilane with an increased cost-effectiveness compared with the prior art.
• the object is achieved by a method in which a silicon tetrachloride educt gas and a hydrogen-containing educt gas are reacted at a temperature of 700 0 C to 1500 0 C, wherein a trichlorosilane-containing product mixture is formed, characterized in that a cooling of the product mixture by means of a heat exchanger takes place, wherein the cooling of the product mixture to a temperature TAb kü hi u ng during a residence time of the reaction gases in the heat exchanger ⁇ [ms] is carried out, where applicable
• the production costs for trichlorosilane are reduced by the better energy integration, the increase in the space-time yield and the improvement of the conversion rate of the tetrachlorosilane conversion.
• a heat exchanger consisting of a material which is inert under the reaction conditions and whose construction allows a very short residence time of the product gas, a backreaction becomes extensive prevented and greatly improved by the heating of the educt gases, the energy balance.
• silicon tetrachloride is reacted with hydrogen at egg ner temperature of 900 0 C to HOO 0 C to the reaction.
• 7 ⁇ B ⁇ 30 applies for the temperature of the cooled product mixture preferably applies: 200 0 C ⁇ Abkühiung ⁇ 800 0 C. Particularly preferably 28O 0 C ⁇ T ⁇ ü ⁇ ung ⁇ 700 0 C applies.
• Reactor less than 0.5 s.
• a suitable for the process according to the invention heat exchanger for cooling the product gas or. for the simultaneous heating of the educt gases preferably consists of a material selected from the group consisting of silicon carbide, silicon nitride, quartz glass, graphite, SiC-coated graphite and a combination of these materials.
• the heat exchanger consists of silicon carbide.
• the heat exchanger is preferably a plate or shell and tube heat exchanger with the plates with channels or capillaries arranged in stacks (Fig. Ia-If).
• the arrangement of the plates is preferably designed so that only product gas flows in one part of the capillaries or channels and only educt gas in the other part. Mixing of the gas streams must be avoided.
• the various gas streams can be conducted in countercurrent or also in direct current.
• the construction of the heat exchanger is chosen so that the released energy is used at the same time for heating the educt gas with the cooling of the product gas.
• the capillaries can also be arranged in the form of a shell-and-tube heat exchanger. In this case, one gas flow flows through the tubes (capillaries) while the other gas flow flows around the tubes.
• heat exchangers that satisfy at least one, preferably more, of the following design features are particularly preferred:
• the hydraulic diameter (Dh) of the channels or capillaries defined as 4 ⁇ cross-sectional area / circumference, is less than 5 mm, preferably less than 3 mm.
• the exchange surface to volume ratio is> 400 rrf 1 '
• the heat transfer coefficient is greater than 300 watts / m 2 K.
• the heat exchanger 3 can be arranged immediately after the reaction zone (FIG. 2), but it can also be connected to the reactor 2 via a heated line, which is preferably kept at the reaction temperature. After the reaction mixture (product gas) within 50 ms to below 700 0 C Stand- Is cooled, the reaction gas can be forwarded in a conventional cooler.
• Fig. Ia-If show by way of example the design of two embodiments of heat exchanger internals suitable for the method according to the invention.
• Fig. 2 schematically shows the structure of an apparatus for carrying out the process according to the invention (1 silane pump, 2 reactors, 3 heat exchangers).
• Fig. 3 shows the temperature profile in the heat exchanger according to Example 5.
• the experiments were carried out in a quartz glass reactor.
• the reactor is designed to be divided into different zones, which zones can be heated to different temperatures.
• a heat exchanger is connected in direct connection to the last heating zone.
• the gas residence time in the individual zones can be varied within a wide range by the installation of corresponding displacers.
• the gas mixture leaving the reactor as well as the heat exchanger can be analyzed for its composition via a sampling point both online and offline (gas chromatography).
• Tetrachlorosilane 79 50% trichlorosilane 20, 05%
• This example shows that the Sitri yield remains high when cooled to 700 ° C. within 25 ms.
• the temperature in the reaction zone was 1100 0 C, the pressure was 28.5 kPa.
• the residence time of the gas in the reaction zone was 0.30 s.
• the product mixture showed the following composition after condensation [wt. %]: Tetrachlorosilane 81, 8% trichlorosilane 19, 1% dichlorosilane 0, 10%

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Silicon Compounds (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2005
  • 2005-02-03 DE DE102005005044A patent/DE102005005044A1/de not_active Withdrawn
• 2006
  • 2006-01-26 JP JP2007553509A patent/JP4819830B2/ja not_active Expired - Fee Related
  • 2006-01-26 WO PCT/EP2006/000692 patent/WO2006081980A2/de active Application Filing
  • 2006-01-26 US US11/815,353 patent/US20080112875A1/en not_active Abandoned
  • 2006-01-26 CN CN2006800032311A patent/CN101107197B/zh not_active Expired - Fee Related
  • 2006-01-26 EP EP06704560A patent/EP1843976A2/de not_active Withdrawn
  • 2006-01-26 KR KR1020077018736A patent/KR100908465B1/ko not_active IP Right Cessation
• 2012
  • 2012-08-14 US US13/585,235 patent/US20120308465A1/en not_active Abandoned

Non-Patent Citations (1)

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