CA1085585A - Method for the preparation of trichlorosilane and silicon tetrachloride - Google Patents
Method for the preparation of trichlorosilane and silicon tetrachlorideInfo
- Publication number
- CA1085585A CA1085585A CA282,169A CA282169A CA1085585A CA 1085585 A CA1085585 A CA 1085585A CA 282169 A CA282169 A CA 282169A CA 1085585 A CA1085585 A CA 1085585A
- Authority
- CA
- Canada
- Prior art keywords
- silicon
- reaction
- reactor
- hydrogen chloride
- gaseous
- 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.)
- Expired
Links
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
-
- 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
- C01B33/04—Hydrides of silicon
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Silicon Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
The invention is concerned with a method for the preparation of silicon tetrachloride and trichlorosilane by reaction of silicon or silicon-containing solid materials with hydrogen chloride in the presence of gaseous silicon tetra-chloride, at elevated temperature in a fluidized bed. The method of the invention is characterized in that the composition of the reaction products is controlled by operating with 0.2 to 10 parts by volume gaseous silicon tetrachloride per part by volume hydrogen chloride and with a specific reactor cross-sectional load of 250 to 2500 kg/m2.h, at a constant temperature between 250 and 500°C; the gaseous reaction products are thereafter drawn off from the reactor and separated.
The invention is concerned with a method for the preparation of silicon tetrachloride and trichlorosilane by reaction of silicon or silicon-containing solid materials with hydrogen chloride in the presence of gaseous silicon tetra-chloride, at elevated temperature in a fluidized bed. The method of the invention is characterized in that the composition of the reaction products is controlled by operating with 0.2 to 10 parts by volume gaseous silicon tetrachloride per part by volume hydrogen chloride and with a specific reactor cross-sectional load of 250 to 2500 kg/m2.h, at a constant temperature between 250 and 500°C; the gaseous reaction products are thereafter drawn off from the reactor and separated.
Description
The object of the present invention is a method for the preparation of trichlorosilane and silicon tetrachloride, wherein silicon or silicon-containing materials are converted with hydrogen chloride in a fluidized bed at temperatures between 250 and 500C.
The reaction between silicon and chlorinating agents such as chlorine or hydrogen chloride is known to be intensely exothermic. The higher the reaction temperature, the greater is the proportion of silicon tetrachloride.
The exothermy of the process, the level of the substance conversion aimed at, and the ratio of the desired end products largely determine the method used. Working on fixed, particulate silicon or silicon-containing materials in shaft furnaces impedes the dissipation of the reaction heat;
this causes local overheating points in the contact bed to the extent of melting of the solid matter used. In this way the space-time-yield is reduced and a controlled influencing of the heavily temperature-dependent ratio of the quantities of trichlorosilane and silicon tetrachloride formed in the reac-tion is considerably impeded.
These disadvantages of the uneven temperature distribution in the shaft furnace are reduced through working in a fluidized bed. When working in the fluidized bed using chlorine as chlorinating agent the reaction is still so violent that local overheating points result. It has therefore already been proposed in the German Auslegeschrift 12 19 454 that the chlorination of silicon at temperatures above 400C should be effected in thè presence of a thinning agent in or~er to rcduce the violence of the reaction. However, these measures are only necessary when chlorine is used as chlorinating agent and the chlorination is to be effected at temperatures above 400C, i.e., therefore if SiC14 is desired as the main product.
- 1 -- q~ .
1~85585 When workin~ in a fluidized bed the ratio of the chlorosilane obtained does not, however, only depend directly on the reactor temperature set, but furthermore also on a homogenous quality in the fluidized bed. This can only be maintained in narrow limits since both the fluidization agent used, the hydrogen chloride, and the fluidized particles of solid matter are reaction partners. These limits are set by:
1) the velocity of the vortex point,
The reaction between silicon and chlorinating agents such as chlorine or hydrogen chloride is known to be intensely exothermic. The higher the reaction temperature, the greater is the proportion of silicon tetrachloride.
The exothermy of the process, the level of the substance conversion aimed at, and the ratio of the desired end products largely determine the method used. Working on fixed, particulate silicon or silicon-containing materials in shaft furnaces impedes the dissipation of the reaction heat;
this causes local overheating points in the contact bed to the extent of melting of the solid matter used. In this way the space-time-yield is reduced and a controlled influencing of the heavily temperature-dependent ratio of the quantities of trichlorosilane and silicon tetrachloride formed in the reac-tion is considerably impeded.
These disadvantages of the uneven temperature distribution in the shaft furnace are reduced through working in a fluidized bed. When working in the fluidized bed using chlorine as chlorinating agent the reaction is still so violent that local overheating points result. It has therefore already been proposed in the German Auslegeschrift 12 19 454 that the chlorination of silicon at temperatures above 400C should be effected in thè presence of a thinning agent in or~er to rcduce the violence of the reaction. However, these measures are only necessary when chlorine is used as chlorinating agent and the chlorination is to be effected at temperatures above 400C, i.e., therefore if SiC14 is desired as the main product.
- 1 -- q~ .
1~85585 When workin~ in a fluidized bed the ratio of the chlorosilane obtained does not, however, only depend directly on the reactor temperature set, but furthermore also on a homogenous quality in the fluidized bed. This can only be maintained in narrow limits since both the fluidization agent used, the hydrogen chloride, and the fluidized particles of solid matter are reaction partners. These limits are set by:
1) the velocity of the vortex point,
2) the size and shape of the particles of solid matter,
3) the gas throughput, and
4) the discharged quantity of solid matter from the reactor.
If, e.g., the gas throughput is decreased a compression results and thus also a considerable overheating of the bed with its resultant, in any undesired case, increase in the yield of SiC14. Furthermore, higher velocities of flow bring about a lower HCl-conversion and hasten the discharge of the solid matter. This causes a decline of the yield in respect of the silicon-containing starting materials and the hydrochloric acid and increases the expenditure in the reprocessing of the reaction product.
The task therefore was to take steps in converting silicon with hydrogen chloride in a fluidized bed which make it possible to vary the reactor output and to set a specific ratio of SiC14:SiHC13 through control of the reaction temperature.
In fulfillment of this task a method was found for the preparation of silicon tetrachloride and trichlorosilane by reaction of silicon or silicon-containing solid materials with hydrogen chloride in the presence of gaseous silicon tetra-chloride, at elevated temperature in a fluidized bed, which is characterized in that the composition of the reaction products is controlled by operating with 0.2 to 10 parts by volume gaseous silicon tetrachloride per part by volume hydrogen chloride and with a specific reactor cross-sectional load of 250 to 2500 kg/m2.h, at a constant temperature between 250 and 500C, the gaseous reaction products being thereafter drawn off from the reactor and separated.
By means of this method it is possible to largely reduce the afore-mentioned difficulties and to such control the reaction that even with different reactor outputs, a homogenous fluidized bed, a stabilization of the set temperature and thus a desired ratio of SiC14/SiHC13 is obtained. The productive capacity of the fluidized bed reactor can be varied here within further limits depending on the quantity of the additionally introduced silicon tetrachloride vapor. The maximum output of the fluidized bed obviously depends on the size of the reactor.
The amount of silicon tetrachloride vapor is selected, according to the desired productive capacity and the desired SiC14/SiHC13 ratio, such that after mixing with the used hydrogen chloride, a specific reactor cross-sectional load in the range of 250 kg/m2.h to 2500 kg/m2.h results. The preferred range lies between 1200 and 1600 kg/m2.h. The ratio of the dosed amount of SiC14 : HCl should here lie between 0.2:1 and 10:1.
If a lower productive capacity is desired, a high proportion of silicon tetrachloride vapor is mixed with the hydrogen chloride and the reactor is operated with low specific cross-sectional loads. If, on the other hand, a high productive capacity of the reactor is desired, then a small amount of silicon tetrachloride vapor is mixed in and a high specific cross-sectional load is set.
Generally, the reaction is effected in a reaction column with constant diameter. It is also possible, however, to construct the geometry of the reactor such that the specific cross-sectional loads are formed in two inter-transitional zones with different diameters. The lower part 10855~5 of the reactor is then to be operated with high specific cross-sectional loads and the upper expanded part with low loads. It is thus unnecessary for the specific cross-sectional load to be the same over the entire reactor uniformly; it has only to lie within the specified limits.
The solid materials of the fluidized bed comprise metallic silicon and alloys or intermetallic compounds of silicon with iron, carbon, phosphorus or nitrogen, whose proportion of silicon lies above 50%. As examples may be mentioned ferrosilicon, silicon carbide or silicon nitride.
The grain size of the silicon or silicon-containing solid materials should preferably lie between 20 and 200 ~m. It is, however, quite possible to use solid materials with a grain size diameter of up to 500 ~m.
The molar ratio between silicon and hydrogen chloride should be selected such that the hydrogen chloride is added at least in the quantity which is stoichiometrically necessary to form the desired ratio of SiC14/SiHC13.
Depending on the desired product composition the reaction temperature lies between 250 and 500C, preferably below 400C if the proportion of trichlorosilane is to pre-dominate.
A method of procedure according to the present invention will be described briefly with reference to the annexed sketch whieh shows a reaetor.
SiC14-Vapor, heated to approximately 300C, is introduced through line 1 into the approach flow section at the lower end of the reaetor in which are located silicor- or ferrosilieon with an average grain diameter of 150 to 200 ~m.
After setting a speeific cross-sectional load of 1500 kg/m2.h and a system temperature, also of 300C, hydrogen chloride corresponding to the desired production level and likewise 10~55~5 heated to 300C, is fed in through line 2 above the SiC14-inlet line and the amount of SiC14 throttled there to a corresponding degree so that the specific reactor cross-sectional load remains constant. Silicon or ferrosilicon of the aforementioned grain size is now continuously dosed through line 3 into the reaction zone 4 in which the conversion of hydrogen chloride and silicon is effected. The resultant reaction heat is drawn off through a cooling system 7 installed in the reactor and the temperature thus kept to a specific value corresponding to the desired trichloro-proportion in the reaction product. The reaction product leaves the apparatus in gaseous form through line 5. The discharge of the solid matter residue is effected continuously or intermittently through line 6 at the lower part of the reactor.
The subject matter of this application is related to our copending Canadian application No. 216,980 filed December 27, 1974.
If, e.g., the gas throughput is decreased a compression results and thus also a considerable overheating of the bed with its resultant, in any undesired case, increase in the yield of SiC14. Furthermore, higher velocities of flow bring about a lower HCl-conversion and hasten the discharge of the solid matter. This causes a decline of the yield in respect of the silicon-containing starting materials and the hydrochloric acid and increases the expenditure in the reprocessing of the reaction product.
The task therefore was to take steps in converting silicon with hydrogen chloride in a fluidized bed which make it possible to vary the reactor output and to set a specific ratio of SiC14:SiHC13 through control of the reaction temperature.
In fulfillment of this task a method was found for the preparation of silicon tetrachloride and trichlorosilane by reaction of silicon or silicon-containing solid materials with hydrogen chloride in the presence of gaseous silicon tetra-chloride, at elevated temperature in a fluidized bed, which is characterized in that the composition of the reaction products is controlled by operating with 0.2 to 10 parts by volume gaseous silicon tetrachloride per part by volume hydrogen chloride and with a specific reactor cross-sectional load of 250 to 2500 kg/m2.h, at a constant temperature between 250 and 500C, the gaseous reaction products being thereafter drawn off from the reactor and separated.
By means of this method it is possible to largely reduce the afore-mentioned difficulties and to such control the reaction that even with different reactor outputs, a homogenous fluidized bed, a stabilization of the set temperature and thus a desired ratio of SiC14/SiHC13 is obtained. The productive capacity of the fluidized bed reactor can be varied here within further limits depending on the quantity of the additionally introduced silicon tetrachloride vapor. The maximum output of the fluidized bed obviously depends on the size of the reactor.
The amount of silicon tetrachloride vapor is selected, according to the desired productive capacity and the desired SiC14/SiHC13 ratio, such that after mixing with the used hydrogen chloride, a specific reactor cross-sectional load in the range of 250 kg/m2.h to 2500 kg/m2.h results. The preferred range lies between 1200 and 1600 kg/m2.h. The ratio of the dosed amount of SiC14 : HCl should here lie between 0.2:1 and 10:1.
If a lower productive capacity is desired, a high proportion of silicon tetrachloride vapor is mixed with the hydrogen chloride and the reactor is operated with low specific cross-sectional loads. If, on the other hand, a high productive capacity of the reactor is desired, then a small amount of silicon tetrachloride vapor is mixed in and a high specific cross-sectional load is set.
Generally, the reaction is effected in a reaction column with constant diameter. It is also possible, however, to construct the geometry of the reactor such that the specific cross-sectional loads are formed in two inter-transitional zones with different diameters. The lower part 10855~5 of the reactor is then to be operated with high specific cross-sectional loads and the upper expanded part with low loads. It is thus unnecessary for the specific cross-sectional load to be the same over the entire reactor uniformly; it has only to lie within the specified limits.
The solid materials of the fluidized bed comprise metallic silicon and alloys or intermetallic compounds of silicon with iron, carbon, phosphorus or nitrogen, whose proportion of silicon lies above 50%. As examples may be mentioned ferrosilicon, silicon carbide or silicon nitride.
The grain size of the silicon or silicon-containing solid materials should preferably lie between 20 and 200 ~m. It is, however, quite possible to use solid materials with a grain size diameter of up to 500 ~m.
The molar ratio between silicon and hydrogen chloride should be selected such that the hydrogen chloride is added at least in the quantity which is stoichiometrically necessary to form the desired ratio of SiC14/SiHC13.
Depending on the desired product composition the reaction temperature lies between 250 and 500C, preferably below 400C if the proportion of trichlorosilane is to pre-dominate.
A method of procedure according to the present invention will be described briefly with reference to the annexed sketch whieh shows a reaetor.
SiC14-Vapor, heated to approximately 300C, is introduced through line 1 into the approach flow section at the lower end of the reaetor in which are located silicor- or ferrosilieon with an average grain diameter of 150 to 200 ~m.
After setting a speeific cross-sectional load of 1500 kg/m2.h and a system temperature, also of 300C, hydrogen chloride corresponding to the desired production level and likewise 10~55~5 heated to 300C, is fed in through line 2 above the SiC14-inlet line and the amount of SiC14 throttled there to a corresponding degree so that the specific reactor cross-sectional load remains constant. Silicon or ferrosilicon of the aforementioned grain size is now continuously dosed through line 3 into the reaction zone 4 in which the conversion of hydrogen chloride and silicon is effected. The resultant reaction heat is drawn off through a cooling system 7 installed in the reactor and the temperature thus kept to a specific value corresponding to the desired trichloro-proportion in the reaction product. The reaction product leaves the apparatus in gaseous form through line 5. The discharge of the solid matter residue is effected continuously or intermittently through line 6 at the lower part of the reactor.
The subject matter of this application is related to our copending Canadian application No. 216,980 filed December 27, 1974.
Claims (4)
1. A method for the preparation of silicon tetra-chloride and trichlorosilane by reaction of silicon or silicon-containing solid materials with hydrogen chloride in the presence of gaseous silicon tetrachloride, at elevated temperature in a fluidized bed, characterized in that the composition of the reaction products is controlled by operating with 0.2 to 10 parts by volume gaseous silicon tetrachloride per part by volume hydrogen chloride and with a specific reactor cross-sectional load of 250 to 2500 kg/m2.h, at a constant temperature between 250 and 500°C, the gaseous reaction products being thereafter drawn off from the reactor and separated.
2. Method according to claim 1, characterized in that after distilling off and separating the reaction mixture a part of the SiCl4 obtained is supplied to the reactor again in vapor form, the required distillation heat being supplied by the reaction heat.
3. A method according to claim 1, wherein the specific reactor cross-sectional load ranges from 1200 to 1600 kg/m2.h.
4. A method according to claim 1, wherein the temperature ranges from 250°C to 400°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19762630542 DE2630542C3 (en) | 1976-07-07 | 1976-07-07 | Process for the production of trichlorosilane and silicon tetrahedral |
| DEP2630542.0 | 1976-07-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1085585A true CA1085585A (en) | 1980-09-16 |
Family
ID=5982438
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA282,169A Expired CA1085585A (en) | 1976-07-07 | 1977-07-06 | Method for the preparation of trichlorosilane and silicon tetrachloride |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS536297A (en) |
| BE (1) | BE856480A (en) |
| CA (1) | CA1085585A (en) |
| DE (1) | DE2630542C3 (en) |
| ES (1) | ES460451A1 (en) |
| FR (1) | FR2357481A1 (en) |
| GB (1) | GB1530986A (en) |
| IT (1) | IT1112065B (en) |
| NL (1) | NL7707499A (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2704975C2 (en) * | 1977-02-07 | 1982-12-23 | Wacker-Chemie GmbH, 8000 München | Heat exchange device for fluidized bed reactors for carrying out gas / solid reactions, in particular for producing silicon-halogen compounds by means of silicon-containing contact masses |
| JPS5832011A (en) * | 1981-08-17 | 1983-02-24 | Nippon Aerojiru Kk | Preparation of trichlorosilane and silicon tetrachloride from silicon and hydrogen chloride |
| DE3303903A1 (en) * | 1982-02-16 | 1983-08-25 | General Electric Co., Schenectady, N.Y. | Process for the preparation of trichlorosilane from silicon |
| DE3828344C1 (en) * | 1988-08-20 | 1989-07-06 | Huels Ag, 4370 Marl, De | |
| US5051248A (en) * | 1990-08-15 | 1991-09-24 | Dow Corning Corporation | Silane products from reaction of silicon monoxide with hydrogen halides |
| DE4033611A1 (en) * | 1990-10-23 | 1992-04-30 | Huels Chemische Werke Ag | METHOD FOR OBTAINING LOW CHLORIDE OVEN ASH IN THE CONVERSION OF RAW SILICON TO CHLORINE SILANES |
| US5160720A (en) * | 1990-12-12 | 1992-11-03 | Dow Corning Corporation | Metal catalyzed production of tetrachlorosilane |
| US5176892A (en) * | 1990-12-06 | 1993-01-05 | Dow Corning Corporation | Supported metal catalyzed production of tetrachlorosilane |
| DE102006009954A1 (en) * | 2006-03-03 | 2007-09-06 | Wacker Chemie Ag | Recycling of high-boiling compounds within a chlorosilane composite |
| US8178051B2 (en) * | 2008-11-05 | 2012-05-15 | Stephen Michael Lord | Apparatus and process for hydrogenation of a silicon tetrahalide and silicon to the trihalosilane |
| US20140086815A1 (en) * | 2011-03-25 | 2014-03-27 | Evonik Degussa Gmbh | Use of silicon carbide tubes with a flanged or flared end |
| DE102012216356A1 (en) * | 2012-09-14 | 2014-03-20 | Evonik Industries Ag | Process for the preparation of chlorosilanes by means of high-boiling chlorosilanes or chlorosilane-containing mixtures |
| WO2016099833A1 (en) | 2014-12-19 | 2016-06-23 | Dow Corning Corporation | Process for preparing monohydrogentrihalosilanes |
| CN110002449A (en) * | 2019-04-12 | 2019-07-12 | 四川永祥多晶硅有限公司 | A kind of chlorosilane refining system and refining methd |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU120510A1 (en) * | 1958-05-06 | 1958-11-30 | К.А. Андрианов | Method for simultaneous production of trichlorosilane and silicon tetrachloride |
| GB963745A (en) * | 1961-01-05 | 1964-07-15 | British Titan Products | Halogenation of silicon-containing materials |
| US3704104A (en) * | 1970-06-01 | 1972-11-28 | Texas Instruments Inc | Process for the production of trichlorosilane |
-
1976
- 1976-07-07 DE DE19762630542 patent/DE2630542C3/en not_active Expired
-
1977
- 1977-07-04 GB GB2798277A patent/GB1530986A/en not_active Expired
- 1977-07-05 BE BE179082A patent/BE856480A/en unknown
- 1977-07-06 FR FR7720871A patent/FR2357481A1/en not_active Withdrawn
- 1977-07-06 ES ES460451A patent/ES460451A1/en not_active Expired
- 1977-07-06 IT IT5015877A patent/IT1112065B/en active
- 1977-07-06 JP JP8088977A patent/JPS536297A/en active Pending
- 1977-07-06 CA CA282,169A patent/CA1085585A/en not_active Expired
- 1977-07-06 NL NL7707499A patent/NL7707499A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| BE856480A (en) | 1977-10-31 |
| JPS536297A (en) | 1978-01-20 |
| NL7707499A (en) | 1978-01-10 |
| ES460451A1 (en) | 1978-06-01 |
| FR2357481A1 (en) | 1978-02-03 |
| DE2630542B2 (en) | 1980-05-08 |
| IT1112065B (en) | 1986-01-13 |
| DE2630542A1 (en) | 1978-01-12 |
| GB1530986A (en) | 1978-11-01 |
| DE2630542C3 (en) | 1981-04-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |