For dichlorosilane

TEMPERATURE "" Degree Fahrenheit Fig. 1. Vapor pressure curve for dichlorosilane. 

The most common cylinder valve used for dichlorosilane is a stainless steel diaphragm valve with a Connection CGA 678 outlet. The cylinder valve body has a combination CG-4 type pressure relief device consisting of a fusible metal plug, melting about 165°F (74°C), which is protected from the cylinder contents by a frangible metal disk, i.e. a rupture disk, rated at 250 psig (1724 kPa). 

Material Safety Data Sheet for Dichlorosilane (L-4587A), Union Carbide Corporation, Linde Division, 39 Old Ridgebury Road, Danbury, CT 06817. (1985) Matheson Gas Data Book, 6th ed., Matheson Gas Products, Inc., Secaucus, NJ 07094. (1980)... 

WurtZ-Type Coupling of Dihalosilanes. Several approaches have been developed for the synthesis of polysdanes. However, the most commonly utilized method is based on the Wurtz-type alkah metal coupling of dichlorosilanes. Both homo- and copolymers can be prepared this way (eq. 10). 

The thermal decomposition of silanes in the presence of hydrogen into siUcon for production of ultrapure, semiconductor-grade siUcon has become an important art, known as the Siemens process (13). A variety of process parameters, which usually include the introduction of hydrogen, have been studied. Silane can be used to deposit siUcon at temperatures below 1000°C (14). Dichlorosilane deposits siUcon at 1000—1150°C (15,16). Ttichlorosilane has been reported as a source for siUcon deposition at >1150° C (17). Tribromosilane is ordinarily a source for siUcon deposition at 600—800°C (18). Thin-film deposition of siUcon metal from silane and disilane takes place at temperatures as low as 640°C, but results in amorphous hydrogenated siUcon (19). 

Oxidation. AH inorganic siUcon hydrides are readily oxidized. Silane and disilane are pyrophoric in air and form siUcon dioxide and water as combustion products thus, the soot from these materials is white. The activation energies of the reaction of silane with molecular and atomic oxygen have been reported (20,21). The oxidation reaction of dichlorosilane under low pressure has been used for the vapor deposition of siUcon dioxide (22). 

Other specialty silanes used in microelectronic apphcations include dichlorosilane and disilane. Trihromosilane [7789-57-3] iodosilanes, and trisilylamine [13862-16-3] are of interest for microelectronics in low temperature deposition technologies. 

Fluidized bed reactors do not have to perform poorly, but special conditions must be maintained for good performance. A basic process for silicone manufacturing, which is not practiced much anymore, is the reaction of silicon metal with methyl chloride to form dimethyl dichlorosilane ... 

In practice vapours of the hydrocarbon halide, e.g. methyl chloride, are passed through a heated mixture of the silicon and copper in a reaction tube at a temperature favourable for obtaining the optimum yield of the dichlorosilane, usually 250-280°C. The catalyst not only improves the reactivity and yield but also makes the reaction more reproducible. Presintering of the copper and silicon or alternatively deposition of copper on to the silicon grains by reduction of copper (I) chloride is more effective than using a simple mixture of the two elements. The copper appears to function by forming unstable copper methyl, CUCH3, on reaction with the methyl chloride. The copper methyl then decomposes into free methyl radicals which react with the silicon. 

In the case of phenylchlorosilanes some modifications are made to the process. Chlorobenzene is passed through the reaction tube, which contains a mixture of powdered silicon and silver (10% Ag), the latter as catalyst. Reaction temperatures of 375-425°C are significantly higher than for the chloro-methylsilanes. An excess of chlorobenzene is used which sweeps out the high boiling chlorophenysilanes, of which the dichlorosilanes are predominant. The unused chlorobenzene is fractionated and recycled. 

Dichlorosilane C E T Nickel and nickel steels and Stainless steel for moist gas... 

Carbonylate anions are the most suitable starting material for the synthesis of silylmetal compounds. A prerequisite for the preparation of compounds with a formal M = Si double bond is the use of metallate dianions like Na2Fe(CO)4 (Collman s reagent) together with the respective dichlorosilanes [96]. 

The alkylation of benzene derivatives with methyl(vinyl)dichlorosilane (3) will be described in detail. Alkylation of monosubstituted benzenes such as toluene, chlorobenzene, and biphenyl at 75-80 C for 2 h afforded the corresponding alkylated products in 50-63% yields." ... 

Cu and Ag on Si(lll) surfaces. In the last example, we come back to surfaces. It is well known (44-46) that Cu catalyzes the formation of dimethyl-dichlorosilane from methylchloride and solid silicon, which is a crucial technological step in the synthesis of silicone polymers. Even today, the details of the catalytic mechanism are unclear. Cu appears to have unique properties for example, the congener Ag shows no catalytic activity. Thus, the investigation of the differences between Cu and Ag on Si surfaces can help in understanding the catalytic process. Furthermore, the bonding of noble metal atoms to Si surfaces is of great importance in the physics and chemistry of electronic devices. 

In Olin s attempts to derivatize dilithiated products of o-carborane with chlorosilanes for further reaction with ammonia, it was observed that cyclic compounds, instead of polymers, were produced by the interaction of the substituents on the adjacent carbon atoms in the o-carborane units.11 However, when a linear dimethoxy intermediate of m-carborane was reacted as an equimolar mixture with dichlorosilane in the presence of the catalyst FeCl3, the quantitative evolution of CH3C1 was observed... 

We examined a variety of dihalosilanes using ultrasonic waves and alkali metals(37). The mild conditions permitted led to fewer products than are normally observed in these reactions and the first evidence that silylenes can be important intermediates in metal-dihalosilane reactions in solution. Our results for some dichlorosilanes reacting with lithium metal are summarized below. 

The hydrosilylation of butadiene proceeds with palladium compounds even in the absence of phosphines. Other ligands, such as glyoxime, benzonitrile, and 1,5-cyclooctadiene, can be used as effective ligands for the hydrosilylation of butadiene (65, 67). The reaction of trichlorosilane and dichlorosilane with isoprene proceeded regioselectively and stereo-selectively to give Z-l-trichlorosilyl-2-methyl-2-butene (67) (65, 66, 68). No reaction of trimethylsilane with isoprene took place, and this shows the lower reactivity of trialkylsilane. 

These unusual results suggest that dichlorosilane may have added to these alkenes by a thermal or free-radical mechanism, and that the addition was not catalyzed by chloroplatinic acid in the usual way. No experiment in which these reagents were heated in the absence of platinum was described.. wm-Tetrarnethyldisiloxane added to 3-heptene at reflux with chloroplatinic acid in mole ratios of 1/2.1/10-5 at reflux for 48 hours to give an excellent yield of a mixture of 1,3-diheptyltetramethyl-disiloxanes. The heptyl substituents were mostly rc-heptyl, but they included a considerable amount of 3- and 4-heptyl as well. No 2-heptyl substituents were detected (2a). 

Kunai and Ishikawa et al. have reported that electrolysis of monochloro-silanes in 1,2-dimethoxyethane using a platinum cathode and a mercury anode gives disilanes in high yield (Scheme 40) [84]. Silver can also be used as an excellent anode material in place of mercury. The electrolysis of a mixture of two different monochlorosilanes produces unsymmetrical disilanes. Trisilanes can also be synthesized by the electrolysis of a mixture of monochlorosilanes and dichlorosilanes. They also reported that the use of copper electrodes is effective for the synthesis of disilanes, trisilanes, tetrasilanes, and pentasilanes [85]. 

The use of sacrificial aluminum electrodes is also effective for the eleetrore-ductive synthesis of disilanes and polysilanes from monochlorosilanes and dichlorosilanes, respectively as reported by Nonaka et al. and Dunogues et al. independently [88],... 

In some cases, the cathodic reduction of dichlorosilane gives the corresponding disilene. For example, the electrolysis of dimesityldichlorosilane in a divided cell equipped with a mercury pool cathode and silver anode under controlled potential conditions (-3.2V vs Ag/Ag+) affords tetramesityldisilene in 20% yield (Scheme 42) [90]. 

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