trichlorosilane

Trichlorosilane is produced by treating powdered metallurgical grade silicon with blowing hydrogen chloride at 300 °C in a hydrochlorination process.https://www.sec.gov/Archives/edgar/data/1464623/000146462314000005/filename136.htm Hydrogen is also produced, as described in the chemical equation:

:Si + 3 HCl → HCl₃Si + H₂

Yields of 80-90% can be achieved. The main byproducts are silicon tetrachloride (chemical formula SiCl₄), hexachlorodisilane (Si₂Cl₆) and dichlorosilane (H₂SiCl₂), from which trichlorosilane can be separated by distillation.

File:Trichlorsilan-RID.JPG: 2988 (Chlorosilanes). ADR hazard identification number: X338 (Highly flammable liquid, corrosive, which reacts dangerously with water)]]

It is also produced from silicon tetrachloride in a direct chlorination process:https://www.sec.gov/Archives/edgar/data/1464623/000146462314000005/filename136.htm{{Ullmann | author = Simmler, W. | title = Silicon Compounds, Inorganic | doi = 10.1002/14356007.a24_001}}

:Si + 3 SiCl₄ + 2 H₂ → 4 HCl₃Si

Both methods are widely used. The first method is cheaper but yield is hard to control. The second method doesn't require as much control, but needs twice as much capital investment and consumes 120 to 200 kWh/kg compared to 65-90 kWh/kg for the first method. The distillation of TCS purifies it substantially and with it, most of the impurities in the silicon are removed.https://www.sec.gov/Archives/edgar/data/1464623/000146462314000005/filename136.htm

Trichlorosilane is the basic ingredient used in the production of purified polysilicon.

:HCl₃Si → Si + HCl + Cl₂

It can be used in a chemical vapor deposition process called the Siemens process.{{cite web | title=Processes and systems for non-equilibrium trichlorosilane production | website=Google Patents | date=2012-11-10 | url=https://patents.google.com/patent/US9493360B2/en | access-date=2024-06-29}}{{cite web | title=Polysilicon Production: Siemens Process | website=Bernreuter Research | date=2020-06-29 | url=https://www.bernreuter.com/polysilicon/production-processes/ | access-date=2024-06-29}}

Via hydrosilylation, trichlorosilane is a precursor to other useful organosilicon compounds:

:RCH=CH₂ + HSiCl₃ → RCH₂CH₂SiCl₃

Some useful products of this or similar reactions include octadecyltrichlorosilane (OTS), perfluoroctyltrichlorosilane (PFOTCS), and perfluorodecyltrichlorosilane (FDTS). These reagents used in surface science and nanotechnology to form self-assembled monolayers. Such layers containing fluorine decrease surface energy and reduce sticking. This effect is usually exploited as coating for MEMS and microfabricated stamps for a nanoimprint lithography (NIL) and in injection molding tools.{{cite journal|vauthors = Cech J, Taboryski R |title = Stability of FDTS monolayer coating on aluminum injection molding tools|journal = Applied Surface Science|volume = 259|pages = 538–541|year = 2012|doi = 10.1016/j.apsusc.2012.07.078|bibcode = 2012ApSS..259..538C}}

Trichlorosilane is a reagent in the conversion of benzoic acids to toluene derivatives. In the first step of a two-pot reaction, the carboxylic acid is first converted to the trichlosilylbenzyl compound. In the second step, the benzylic silyl derivative is converted to the toluene derivative with base.George S. Li, David F. Ehler, R. A. Benkeser "Methyl Groups By Reduction Of Aromatic Carboxylic Acids With Trichlorosilane - Tri-n-propylamine: 2-methylbiphenyl" Org. Synth. 1977, volume 56, pp. 83. {{doi|10.15227/orgsyn.056.0083}}

Trichlorosilane is highly reactive, and may respond violently (and even explosively) to many compounds. This also includes water, potentially producing silicon dioxide, chlorine, hydrogen, hydrogen chloride (and its aqueous form hydrochloric acid), and heat. Trichlorosilane can cause hazardous chemical reactions with moisture and humidity alone, and should be handled and stored under inert gas.{{Cite report |url=https://www.lindeus.com/-/media/corporate/praxairus/documents/sds/praxair-chlorosilane-a19-sihcl3-safety-data-sheet-sds-p4823.pdf?la=en |title=Trichlorosilane: Safety Data Sheet P-4823 |date=February 3, 2022 |publisher=Linde Inc. |archive-url=https://web.archive.org/web/20220606012024/https://www.lindeus.com/-/media/corporate/praxairus/documents/sds/praxair-chlorosilane-a19-sihcl3-safety-data-sheet-sds-p4823.pdf?la=en |archive-date=June 6, 2022 |url-status=dead}} Spills of trichlorosilane may be neutralized using a 1-1 ratio of sodium hydroxide, or a 2-1 ratio of sodium bicarbonate to trichlorosilane.{{Cite report |url=https://www.nj.gov/health/eoh/rtkweb/documents/fs/1903.pdf |title=Hazardous Substance Fact Sheet: Trichlorosilane |date=October 2010 |publisher=New jersey department of health}} Fires can be extinguished using alcohol-resistant aqueous film-forming foam (AR-AFFF).

• [https://web.archive.org/web/20050313163014/http://www.osha.gov/SLTC/semiconductors/substratemfg/polysiliconprod.html Semiconductors: Silicon: Substrate Manufacture: Polycrystalline silicon Production]

Category:Chlorosilanes