Silicon compounds sulfur derivatives

Fuel-derived sulfur does not interfere with the performance of noble metal exhaust catalysts as strongly as it does with base-metal catalysts. Compatibility with sulfur dioxide was one of the reasons for selecting noble metal catalysts. Fuel contaminants such as organo-silicon compounds have been found... 

Aminolysis of the corresponding halides is the preferred method for the synthesis of dialkylamino derivatives of boron,1 silicon,2 germanium,3 phosphorus,4 arsenic,5 and sulfur.6 (Dialkylamino) chlorosilanes are prepared stepwise by the reaction of silicon tetrachloride with dialkylamines. This method may be utilized equally well for the conversion of alkyl- or aryl-substituted halides [e.g., (CH3) SiCl4. ] or of oxide and sulfide halides (e.g., POCl3 or PSC13) to the corresponding dialkylamino compounds. 

Hydroxysilatrane (66) can undergo nucleophilic displacement at silicon. For example, it reacts with acetyl chloride (in the presence of Et3N) or with acetic acid/acetic anhydride to yield unstable 1-acetoxysilatrane 67 (equation 95)69. 1-Trimethylsiloxysilatrane (68) was obtained by treatment of 66 with chlorotrimethylsilane (equation 96)69. The reaction of 66 with diphenylchlorophosphine in THF led to the substitution product 69 in 37% yield. When treated with sulfur the latter compound was converted to the corresponding thio derivative 70 (equation 97)325. 

Industrial poisoning. The production of silicone products uses substances harmful for human health. These are inorganic substances (ammonia, chlorine, sodium and potassium hydroxides, sulfuric and hydrochloric acids, hydrogen chloride) and organic compounds of various types, such as hydrocarbons (methane, benzene and its homologues), chlorine derivatives (methyl- and ethylchloride, chlorobenzene), alcohols (methyl, ethyl, n-butyl, hydrosite), acetone, pyridine, etc. The information about their toxicity, explosion hazard, effect on human body, as well as maximum allowable concentrations of gases and vapours in the air at workplace can be found in special references.(Ryabov 1970). A comprehensive description of silicone substances is given in Table 29. 

Silicon tetraisothiocyanate was first prepared by Miquel and Reynolds by treating silicon(IV) chloride with lead thiocyanate. Later, Forbes and Anderson prepared many substituted silicon isothiocyanates by metathetical reaction of the corresponding chlorosilanes with silver thiocyanate. On the bases of molecular refraction studies, the latter workers concluded that the silane derivatives are isothiocyanates rather than the isomeric thiocyanates. Conclusive proof that these compounds are isothiocyanates is their formation in good yield from isocyanosilanes and sulfur ... 

Maier. L., Organic phosphorus compounds. Part 98. Synthesis and properties of A-methylaminome-thylphosphonic acid and derivatives. Phosphorus, Sulfur Silicon Relat. Elem., 62, 29, 1991. 

It is not wise to infer the detailed physical nature of a compound from the name alone. In this system the name of the (electropositive) metal is not modified from that of the element, but the name of the electronegative element is, and in the way described in the Substitutive Nomenclature section, above. Similarly we derive oxide and sulfide, for example, from oxygen and sulfur. The same division between electronegative and electropositive parts is evident in the covalent nonionic compotmd SiC, which can be named silicon tetrachloride, though an equally valid substitutive name is tetrachlorosilane. 

The reactions of alkoxyacetylenes with such electrophiles as halogens, carbonyl compounds, derivatives of boron, mercury, sulfur, silicon and germanium usually proceed regioselectively according to equation 49... 

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