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Chlorosilane
Chlorosilanes are a group of reactive, chlorine-containing chemical compounds, related to silane and used in many chemical processes. Each such chemical has at least one silicon-chlorine bond. Trichlorosilane is produced on the largest scale. The parent chlorosilane is silicon tetrachloride ().. Synthesis Hydrochlorosilanes They are prepared by the Müller-Rochow process, which involves treating silicon with hydrogen chloride at elevated temperatures in the presence of a copper catalyst. The idealized equation is :2 Si + 6 HCl → 2 HSiCl3 + 2 H2, Trichlorosilane (HSiCl3) is the main product; dichlorosilane (H2SiCl2) and silicon tetrachloride (SiCl4) are obtained as byproducts. The process was independently discovered by Eugene G. Rochow and Richard Müller in 1940. Methylchlorosilanes Methyltrichlorosilane (CH3SiCl3), dimethyldichlorosilane ((CH3)2SiCl2), and trimethylsilyl chloride ((CH3)3SiCl) are produced by the direct process. They are key reagents in organosilicon chemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichlorosilane
Dichlorosilane, or DCS as it is commonly known, is a chemical compound with the formula H2SiCl2. In its major use, it is mixed with ammonia (NH3) in LPCVD chambers to grow silicon nitride in semiconductor processing. A higher concentration of DCS·NH3 (i.e. 16:1), usually results in lower stress nitride films. History Dichlorosilane was originally prepared in 1919 by the gas-phase reaction of monosilane, SiH4, with hydrogen chloride, HCl, and then reported by Stock and Somieski. It was found that in the gas phase, dichlorosilane will react with water vapor to give a gaseous monomeric prosiloxane, H2SiO. Prosiloxane polymerizes rapidly in the liquid phase and slowly in the gas phase, which results in liquid and solid polysiloxanes n. The liquid portion of the product, which is collected via vacuum distillation, becomes viscous and gelled at room temperature. Hydrolysis was done on a solution of H2SiCl2 in benzene by brief contact with water, and the molecular weight was determine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichlorosilane
Trichlorosilane is an inorganic compound with the formula HCl3Si. It is a colourless, volatile liquid. Purified trichlorosilane is the principal precursor to ultrapure silicon in the semiconductor industry. In water, it rapidly decomposes to produce a siloxane polymer while giving off hydrochloric acid. Because of its reactivity and wide availability, it is frequently used in the synthesis of silicon-containing organic compounds. Production Trichlorosilane is produced by treating powdered metallurgical grade silicon with blowing hydrogen chloride at 300 °C. 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. It is also produced from silicon tetrachloride: :Si + 3 SiCl4 + 2 H2 → 4 HCl3Si Applic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyltrichlorosilane
Methyltrichlorosilane, also known as trichloromethylsilane, is a monomer and organosilicon compound with the formula CH3SiCl3. It is a colorless liquid with a sharp odor similar to that of hydrochloric acid. As methyltrichlorosilane is a reactive compound, it is mainly used a precursor for forming various cross-linked siloxane polymers. Preparation Methyltrichlorosilane results from the direct process of chloromethane with elemental silicon in the presence of a copper catalyst, usually at a temperature of at least 250°C.Rösch, L; et al. "Silicon Compounds, Organic." Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH, Weinheim, 2005. : 2 CH3Cl + Si → (CH3)4−nSiCln + other products While this reaction is the standard in industrial silicone production and is nearly identical to the first direct synthesis of methyltrichlorosilane, the overall process is inefficient with respect to methyltrichlorosilane. Even though dimethyldichlorosilane is usually the major produc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyldichlorosilane
Dimethyldichlorosilane is a tetrahedral, organosilicon compound with the formula Si(CH3)2Cl2. At room temperature it is a colorless liquid that readily reacts with water to form both linear and cyclic Si-O chains. Dimethyldichlorosilane is made on an industrial scale as the principal precursor to dimethylsilicone and polysilane compounds. History The first organosilicon compounds were reported in 1863 by Charles Friedel and James Crafts who synthesized tetraethylsilane from diethylzinc and silicon tetrachloride.Silicon: Organosilicon Chemistry. Encyclopedia of Inorganic Chemistry Online, 2nd ed.; Wiley: New Jersey, 2005. However, major progress in organosilicon chemistry did not occur until Frederick Kipping and his students began experimenting with diorganodichlorosilanes (R2SiCl2) that were prepared by reacting silicon tetrachloride with Grignard reagents. Unfortunately, this method suffered from many experimental problems. In the 1930s, the demand for silicones increas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Tetrachloride
Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colourless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications. Preparation Silicon tetrachloride is prepared by the chlorination of various silicon compounds such as ferrosilicon, silicon carbide, or mixtures of silicon dioxide and carbon. The ferrosilicon route is most common. In the laboratory, can be prepared by treating silicon with chlorine at : : It was first prepared by Jöns Jakob Berzelius in 1823. Brine can be contaminated with silica when the production of chlorine is a byproduct of a metal refining process from metal chloride ore. In rare occurrences, the silicon dioxide in silica is converted to silicon tetrachloride when the contaminated brine is electrolyzed. Reactions Hydrolysis and related reactions Like other chlorosilanes, silicon tetrachloride reacts readily with water: :SiCl4 + 2 H2O → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates. Its melting and boiling points of 1414 °C and 3265 °C, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Müller-Rochow Process
The direct process, also called the direct synthesis, Rochow process, and Müller-Rochow process is the most common technology for preparing organosilicon compounds on an industrial scale. It was first reported independently by Eugene G. Rochow and Richard Müller in the 1940s.. The process involves copper-catalyzed reactions of alkyl halides with elemental silicon, which take place in a fluidized bed reactor. Although theoretically possible with any alkyl halide, the best results in terms of selectivity and yield occur with chloromethane (CH3Cl). Typical conditions are 300°C and 2–5bar. These conditions allow for 90–98% conversion for silicon and 30–90% for chloromethane. Approximately 1.4 Mton of dimethyldichlorosilane (Me2SiCl2) is produced annually using this process.Elschenbroich, Christoph Organometallics VCH, Weinheim, Germany: 1992. . Few companies actually carry out the Rochow process, because of the complex technology and has high capital requirements. Since the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Müller (chemist)
Richard Gustav Müller (17 July 1903 – 7 July 1999) was a German chemist. He and Eugene G. Rochow independently discovered the direct process of organosilicon compounds in 1941. That synthesis, also known as the ''Müller-Rochow process'' is the copper-catalysed reaction of chloromethane with silicon. Müller was awarded the National Prize of East Germany in 1952 for his work. Career Born in Hartha in the state of Saxony, Müller attended the Volksschule (equivalent to elementary and junior high school) in Hartha and the G.E. Lessing Gymnasium (secondary school) in Döbeln. After studying from 1923 to 1931 at the University of Leipzig, he received his doctorate in chemistry. From 1933 onwards he worked as a laboratory manager at Chemische Fabrik von Heyden, a large chemical plant located in Radebeul and famous as the world's first factory to produce salicylic acid on an industrial scale. During his research there, in 1941 he succeeded in achieving industrial production of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silane
Silane is an inorganic compound with chemical formula, . It is a colourless, pyrophoric, toxic gas with a sharp, repulsive smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Silane with alkyl groups are effective water repellents for mineral surfaces such as concrete and masonry. Silanes with both organic and inorganic attachments are used as coupling agents. Production Commercial-scale routes Silane can be produced by several routes. Typically, it arises from the reaction of hydrogen chloride with magnesium silicide: : Mg2Si + 4 HCl -> 2 MgCl2 + SiH4 It is also prepared from metallurgical-grade silicon in a two-step process. First, silicon is treated with hydrogen chloride at about 300 °C to produce trichlorosilane, HSiCl3, along with hydrogen gas, according to the chemical equation : Si + 3 HCl -> HSiCl3 + H2 The trichlorosilane is then converted to a mixture of silane and silicon tetrachloride: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polydimethylsiloxane
Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, as its versatility and properties lead to many applications. It is particularly known for its unusual rheological (or flow) properties. PDMS is optically clear and, in general, inert, non-toxic, and non-flammable. It is one of several types of silicone oil (polymerized siloxane). Its applications range from contact lenses and medical devices to elastomers; it is also present in shampoos (as it makes hair shiny and slippery), food ( antifoaming agent), caulk, lubricants and heat-resistant tiles. Structure The chemical formula of PDMS is , where ''n'' is the number of repeating monomer units.Mark, J. E.; Allcock, H. R.; West, R. “Inorganic Polymers” Prentice Hall, Englewood, NJ: 1992. . Industrial synthesis can begin from dimethy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylsilyl Chloride
Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry. Preparation TMSCl is prepared on a large scale by the ''direct process'', the reaction of methyl chloride with a silicon-copper alloy. The principal target of this process is dimethyldichlorosilane, but substantial amounts of the trimethyl and monomethyl products are also obtained. The relevant reactions are (Me = CH3): : x MeCl + Si → Me3SiCl, Me2SiCl2, MeSiCl3, other products Typically about 2–4% of the product stream is the monochloride, which forms an azeotrope with MeSiCl3. Reactions and uses TMSCl is reactive toward nucleophiles, resulting in the replacement of the chloride. In a characteristic reaction of TMSCl, the nucleophile is water, resulting in hydrolysis to give the hexameth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicone
A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking utensils, thermal insulation, and electrical insulation. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk. Chemistry More precisely called polymerized siloxanes or polysiloxanes, silicones consist of an inorganic silicon–oxygen backbone chain (⋯−Si−O−Si−O−Si−O−⋯) with two organic groups attached to each silicon center. Commonly, the organic groups are methyl. The materials can be cyclic or polymeric. By varying the −Si−O− chain lengths, side groups, and crosslinking, silicones can be synthesized with a wide variety of properties and compositions. They can vary in consistency from liquid to gel to rubber to hard plastic. The most common si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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