Synthesis and PMR spectra of functional methylcyclohexa(hepta, octa)siloxanes and their structural isomers

Conclusions

• 1. Condensation of α,α,ω,ω-tetrachlorodimethylsiloxane with 1,5-dihydroxyhexamethyltrisiloxane involves two intramolecular cyclizations, resulting in the formation of dichlororaethylcyclosiloxanes and heptamethyl(dichloropolymethylsiloxy)cyclotetrasiloxanes, their structural isomers. The proportion of heptamethyl(dichloropolymethylsiloxy)cyclotetrasiloxanes increases as the length of the α,α,ω,ω-tetrachlorodimethylsiloxanes increases.

• 2. Difunctional methylcyclohexa(hepta-, and octa)siloxanes are obtained by condensing α,α,ω,ω)-tetrachlorodimethylsiloxanes with dimethylsilanediol and 1,3-dihydroxytetramethyldisiloxane.