Silicon Tetrachloride SiCl

CuCl, Copper dichloride cr,l 80 SiCl Silicon tetrachloride g... 

Silicon tetrachloride undergoes addition with olefinic and acetylenic unsaturated hydrocarbons. In these addition reactions, one chlorine atom adds to one carbon atom of the double or triple bond while the rest of the unit —SiCls attaches to the other carbon atom forming a sihcon—carbon bond ... 

Silicon tetrabromide SiBr,.. Silicon tetrachloride SiCL.. Silicon tetrafiuoride SiF.. . 

Silicon tetrachloride is made by chlorination of Si at red heat. Hexachlorodisilane (Si2Cl6) can be obtained by interaction of SiCL, and Si at high temperatures or, along with SiCL, and higher chlorides, by chlorination of a silidde such as that of calcium. The higher members, which have highly branched structures, can also be obtained by amine-catalyzed reactions such as... 

Vurzel and Polak (55) carried out extensive kinetic studies of the reduction of silicon tetrachloride to silicon in plasma devices. They first decomposed SiCl4 to SiCls in an adiabatic compression-expansion device and then completed the reduction in an RF plasma. They claimed that the decomposition of SiCl4 to silicon proceeded by a two-stage mechanism of chlorine atom removal ... 

Scheele found that 0.6738 gm. of silicon tetrachloride gave 2.277 gm. of silver chloride. Calculate the atomic weight of silicon. (Assume the equation, SiCl + 4 AgNOg - - 2 HgO = SiOo -f 4 AgCl -f 4NH NOg.)... 

If a very slow current of silicon tetrachloride, SiCl, is passed over silicon at 1200 in a reverberating furnace, kept quite fixed at this temperature, it is noticed that after a certain time silicon has been carried by apparent volatilization into the moderately warm region of the tube, whose temperature is comprised between 500 and 800. In reality, by the action of the silicon tetrachloride on silioon, there is formed silicon trichloride, Si Cle, volatile at these temperatures, which a sudden cooling would allow to be collected, but which, as we have seen, completely decomposes at temperatures included between 700 and 800 . 

In a flask containing dry air and some liquid silicon tetrachloride, SiCl4, the total pressure was 988 torr at 225°C. Halving the volume of the flask increased the pressure to 1742 torr at constant temperature. What is the vapor pressure of SiCl in this flask at 225°C ... 

Comparing the quantities of silicon produced shows that the available SiCL is capable of producing less silicon (37.1 g) than the available Mg (130 g). This confirms the conclusion that silicon tetrachloride, SiCL, is the limiting reactant. 

Explain why silicon tetrachloride, SiCl, reacts rapidly with water, but tetrachloromethane, CCl4, does not react even when heated with water to 100 C. 

Silicon tetrachloride is a liquid at room temperature and can easily be vaporized (it boils at 57.6°C) and transported to the reactor chamber. Methane can be supplied as a high-purity gas directly from a bottle. The reaction between SiCL and CH4 to produce SiC films occurs at 1400°C. Two aspects of the temperature are important ... 

A typical example of such materials is fumed (or pyrogenic) silica, which is produced by a vapour phase hydrolysis of silicon tetrachloride SiCL in an oxygen-hydrogen flame (Brinkmann et al. 2006) ... 

Metallothermic reduction of silicon tetrachloride with zinc. Silicon tetrachloride, SiCl, is preliminarily obtained as a byproduct from the carbochlorination of zircon and, to a lesser extent, from that of pure silica sand with carbon and chlorine. Afterward a high-purity silicon tetrachloride is produced by rectification (i.e., fractional distillation). Simultaneously, zinc is purified by vaporization. Then both chemicals are added to the heated quartz-reaction-heated vessel. Needlelike polycrystalline silicon is grown inside the furnace as a result of the following chemical reaction ... 

Without doubt one of the key events of silicon science occurred in 1824 when Berzelius [12] first Isolated silicon by the reduction of potassium fluorosilicate, K.SIF, with potassium metal and then showed that this element reacted with chlorine to give a volatile, highly reactive material subsequently identified as silicon tetrachloride, SiCl. The next step from silicon to organosilicon science was accomplished by Friedle and Craft [13] in 1865 when they obtained tetraethylsilane by reaction of silicon tetrachloride with dlethylzinc ... 

In addition, this class of chiral phosphoramides could catalyze the enantioselective ring opening of epoxides with silicon tetrachloride (SiCfl) [4]. For instance, the reaction of ds-stilbene oxide with SiCl, proceeded smoothly in the presence of 1 to afford the desired chlorohydrin in an enantiomericaUy enriched form (Scheme 7.3). The reactive ion pair shown in the scheme was proposed to be generated through the activation of SiCl, by the coordination of one phosphoramide 1, serving to activate the epoxide it was confirmed that bis-phosphoramide 2 was far less selective in this reaction. 

Both Neish and Speakman Nature, 1945, 156, 176) and Wolsey and Alexander (Brit. Pat. 594901, 1947), showed that wool could be made unshrinkable by depositing upon it a silicon polymer. Alexander (J.S.D.C., 1950, 66, 349) considers that this is the only example of true masking of the scales with no spot welding involved. The process is described in detail by Alexander, Carter, and Earland J.S.D.C., 1949, 65, 107). The wool was treated with a substance of the general formula R.R. SiCl in an organic solvent such as carbon tetrachloride. The experiments were carried out with dimethyl silicon dichloride. The goods were immersed in the solution, hydroextracted, and then soaked in water at room temperature and dried, when the silicon compound was deposited on the surface of the fibres as an insoluble polymer. 

Figure 7-60. Silicon production by direct decomposition of its tetrachloride (SiCl4) in atmospheric-pressure thermal plasma. Composition of products (1) SiCU (2) SiCb (3) SiCl (4) Si (5) Cl x 0.1 (6) SiClj.

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