Reactivity of functional groups attached to silicon atoms in heterofunctional condensation reactions of organocyclosiloxanes withα,ω-dichloro- andα,ω-dihydroxypolydimethylsiloxanes

1. The polycondensation of bifunctional organocyclotetrasiloxanes with 1, 3-dihydroxytetramethyldisiloxane takes place as an intramolecular process with the formation of an organotricyclosiloxane and also intermolecularly with the formation of oligomeric products. 2. The replacement of a methyl substituent by a phenyl substituent on a silicon atom bearing a reactive chlorine atom in an organocyclotetrasiloxane leads to a considerable decrease in the rate of evolution of HCl on its reaction withα ω-dihydroxydimethylsiloxanes. 3. An increase in the length of the α,ω-dichloro- orα, ω-dihydroxydimethylsiloxanes lead to a decrease in the rate of evolution of HC1 on reaction both with organocyclotetrasiloxanes and with organotricyclooctasiloxanes containing two reactive chlorine atoms. 4. The replacement of Cl atoms by OH groups at silicon atoms to which phenylradicals are attached increase creases the degree of polycondensation.