Kinetics of the condensation of oligosiloxanes containing acetoxyl and hydroxyl end groups catalyzed by uncharged nucleophiles in an acid-base inert solvent

Article abstract of DOI:10.1016/0022-328X(89)80080-4

Condensation of undecamethylpentasiloxane-1-ol (1) with 1-acetoxypentamethyldisiloxane (2) in methylene chloride in the presence of uncharged bases has been studied as a model for the coupling of acetoxyl and hydroxyl ended polydimethylsiloxane chains.Triethylamine acts not only as the acceptor of the acid released in the process but also as a Broensted base catalyst activating silanol group.However, weakly basic but strongly nucleophilic N-heterocycles such as 4-dimethylaminopyridine are more effective catalysts promoting the condensation by acting as nucleophiles to activate the acetoxysilane.