: The objective of the overall effort is to develop new chemical compounds as Halon 1211 replacements. Four families of compounds are particularly promising-phosphorus nitrides, metal compounds, silicon compounds, and tropodegradable halocarbons. This report is Volume I of a 5-volume series of reports: Volume II covers metal compounds; Volume III, phosphorus compounds; Volume IV, tropodegradable halocarbons; and Volume V, laboratory-scale streaming tests. This document assesses silicon compounds as potential halon substitutes. Silicon compounds have lower atmospheric lifetimes than do the closely related carbon compounds. Thus, all other things being equal, Global Warming Potentials (GWP) and Ozone Depletion Potentials (ODP) are lower. To avoid toxicity and stability problems, it is essential that halogen atoms (fluorine, chlorine, bromine, and iodine) not be attached directly to the silicon atom. Such molecules are highly susceptible to hydrolysis with the formation of hydrogen halides. Moreover, the number of hydrogen atoms must be kept low to decrease flammability. With these targets in mind, an assessment of the properties and syntheses of silicon compounds was undertaken. Based on this assessment, a number of silanes and siloxanes containing bromocarbon substituents are recommended for further evaluation.

Advanced Streaming Agent Development Volume 1 - Silicon Compounds.

trans-2-Phenyltetrahydrothiophenium 1-methylide (trans-3), which is generated by fluoride ion-induced desilylation of trans-2-phenyl-1-[(trimethylsilyl)methyl]tetrahydrothiophenium salt (trans-2), gave a mixture of 1,4,5,10a-tetrahydro-3H-2-benzothiocine (4) ([2,3]sigmatropic rearrangement product) and 4-methylsulfanyl-1-phenyl-1-butene (5) (Hofmann elimination product). Ylide trans-3 cannot undergo [2,3]sigmatropic rearrangement because the ylide-carbon is too far from the phenyl group, and trans-3 would instead isomerize to cis-3. In this paper, we discuss the mechanism of the isomerization of trans-3 to cis-3.

Dong Soo Ha

Papers

Preparation of (Trimethylsilyl)methyl Halides and Trifluoromethanesulfonate by Methylene Insertion Using Diazomethane

Preparation of (Trimethylsilyl)methyl Halides and Trifluoromethanesulfonate by Methylene Insertion Using Diazomethane.