Silicon tetrachloride vapor

Klinowski, J., Anderson, M.W., Fyfe, C.A. and Gobbi, G.C. (1983). Dealumination of mordenite using silicon tetrachloride vapor. Zeolites 3, 5-7... 

In the typical flame or vapor-phase hydrolysis process, which uses SiCl4 as the precursor, silicon tetrachloride vapor is fed into a flame using an oxygen carrier gas. Fine (<50 nm), amorphous silica particles form in the flame (57). 

In the plasma deposition process, silicon tetrachloride vapor is passed through an induction-coupled plasma torch using a hydrogen-free oxygen... 

Fyfe et al. (155) also recorded spectra of samples of zeolite Y dealuminated using silicon tetrachloride vapor. This method is discussed in detail in Section... 

A new method of achieving such substitution in synthetic faujasites has been reported by Beyer and Belenykaja (205). It involves passing silicon tetrachloride vapor through a bed of dehydrated zeolite at elevated temperatures. Klinowski et al. (206-209) and Hays et al. (210) applied 29Si and 27A1 MAS NMR to the study of this remarkable reaction in a number of zeolites. 

Fig. 48. 27A1 MAS NMR spectrum at 130.32 MHz of zeolite omega dealuminated with silicon tetrachloride vapor (209).

Silicon nitride powder can be made by the reaction of silicon tetrachloride vapor with gaseous ammonia. The by-product is gaseous hydrogen chloride. Write a balanced equation for the reaction. 

Residual silicon tetrachloride vapor carried through the condenser is retained in the two Dry Ice-acetone traps. This silicon tetrachloride... 

Silicon tetrachloride vapor can be either oxidized or hydrolyzed at high temperature. SiCU can be burned in-oxygen to yield SiOs and CIj (462). Presumably Cli could be recycled to make more SiCU from lump silicon which burns in chlorine gas as easily as coal burns in a stove. However, simpler equipment can be used when SiCU is mixed with CH and burned to produce fine Si02 and HGl. Presumably, the latter could be oxidized to CU for recycling if economics permit. 

Pure silicon nitride in the form of a thin, dense electrically insulating layer can be pyrolytically deposited on molybdenum or graphite by heating the substrate to 1000°C in ammonia and passing over it silicon tetrachloride vapors in a nitrogen carrier gas. 

Namba et al. [171,172] subjected H-ZSM-5 to silicon tetrachloride vapor at temperatures between 450 and 650 °C and observed only a slight increase in the bulk Si/Al ratio from 19 to 24, while the surface Si/Al ratio determined by XPS increased, depending on the reaction temperature, from 18 to 39. Thus, the external crystal shell was preferentially dealuminated upon contact with SiCl4, obviously due to diffusion restrictions. In this way the contribution of the surface layer to the catalytic activity of ZSM-5 zeolite could be diminished and the shape-selectivity effect enhanced. In contrast, Thomas et al. [173] reported that aluminum could be removed from the lattice of ZSM-5 by treatment with SiCl4 at540°C. 

Selective oxide formation within one domain follows similar methods. Kim et al. demonstrated titania and silica hybrid materials formed in self-assembled perpendicular cylinders of poly (ethylene oxide) in PS-b-PEO upon exposure to titanium tetrachloride or silicon tetrachloride vapors. Pai et al. used humidified supercritical carbon dioxide to infiltrate metal alkox-ides such as tetraethylorthosilicate into poly(ethylene oxide)-btocfe-poly(propylene oxide)-btocfe-poly(ethylene oxide) and polyethylene-btod -poly(ethylene oxide) containing trace... 

So-called fumed silica results from a pyrolitic process, as the product of the hydrolysis of silicon tetrachloride vapor in a flame of hydrogen and oxygen, according to the following set of chemical reactions ... 

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