Silicon-containing acetylenes

As has been noted above, the 1,1-allylboration is a much faster reaction when compared with normal 1,1-organoboration. However the reaction rate still increases when acetylenes containing silicon hydrides are used as starting materials. Thus, the reaction of AII3B with bis(dimethylsilyl)acetylene was complete after several hours at... 

Acetylenes containing silicon—Continued 3-(trimethylsilyl)-l-alkynes, 643... 

Hydrosilylation of acetylene with bifunctional hydrosilanes, e.g. (25 equation 12) and (27 equation 13), leads to polymers, e.g. (26) and (28) respectively, which contain silicon in the polymer main chain.2 - °... 

For the corrosive line, the reactor is fully teflon-coated so we can use veiy aggressive products such as chlorides, ammonia or acetylene as precursors. It is possible to use silicon chloride or titanium chloride as precursor products to produce nanopowders containing silicon or titanium. An internal and an external scrubber neutralise the chloride with water (internal scrubber) and sodium hydroxide (NaOH). If we start with liquids or gases for precursors, the particle sizK distribution of the end product will be much better controlled. 

In analogy to the above-mentioned parent disilene, no compounds containing silicon-silicon triple bonds have so far been found. Even their intermediacy could not be proved unequivocally. Two isomers of SiaHa, namely 70 and 71, were detected in a low pressure, low power plasma in a mixture of SiHj and argon by the measurement of their millimeter and submillimeter wave rotational spectrum. Both compounds have no acetylene-type silicon-silicon triple bonds, in agreement with the predictions of theoretical studies . ... 

Without carbon, the basis for life would be impossible. While it has been thought that silicon might take the place of carbon in forming a host of similar compounds, it is now not possible to form stable compounds with very long chains of silicon atoms. The atmosphere of Mars contains 96.2% CO2. Some of the most important compounds of carbon are carbon dioxide (CO2), carbon monoxide (CO), carbon disulfide (CS2), chloroform (CHCb), carbon tetrachloride (CCk), methane (CHr), ethylene (C2H4), acetylene (C2H2), benzene (CeHe), acetic acid (CHsCOOH), and their derivatives. 

Ferrosilicon containing 30-75% of silicon is hazardous, particularly when finely divided, and must be kept in a moisture-tight drum. In contact with water, the impurities present (arsenide, carbide, phosphide) evolve extremely poisonous arsine, combustible acetylene and spontaneously flammable phosphine [1 2],... 

Silicones can be prepared in such a way that they contain only one percent or less of vinyl groups and silicon hydrides, which undergo a catalytic hydrosilylation reaction to give the desired cross-linking (Figure 18.3). Vinyl silanes are made by Si-H addition to acetylene, and thus two hydrosilylations are involved. 

Organic constituents that may be found in ppb levels in WP/F smoke include methane, ethylene, carbonyl sulfide, acetylene, 1,4-dicyanobenzene, 1,3-dicyanobenzene, 1,2-dicyanobenzene, acetonitrile, and acrylonitrile (Tolle et al. 1988). Since white phosphorus contains boron, silicon, calcium, aluminum, iron, and arsenic in excess of 10 ppm as impurities (Berkowitz et al. 1981), WP/F smoke also contains these elements and possibly their oxidation products. The physical properties of a few major compounds that may be important for determining the fate of WP/F smoke in the environment are given in Table 3-3. 

Similar to olefins, acetylenes undergo facile addition reactions. Transition metal-catalyzed hydrosilylation is such a reaction that has been utilized for the synthesis of silicon-containing hyperbranched polymers. 

---