THE PREPARATION OF THE MIXED-ALKALI METAL SILANOLATE K4LI4(OSIME(3))(X)(OCME(3))(8-X) R-THAN-OR-EQUAL-TO-X-GREATER-THAN-OR-EQUAL-TO-5.7) AND THE EFFECTS OF MIXED-ALKALI METALS ON THE ANION-INDUCED RING-OPENINGPOLYMERIZATION OF OCTAMETHYLCYCLOTETRASILOXANE

The novel mixed alkali metal silanolate K4Li4(OSiMe(3))(x)(OCMe(3))(8- x) (x=6.8 (1), 5.7 (2), 8 (3)) has been prepared via the reaction of h examethyldisiloxane with n-butyllithium and potassium t-butoxide in TH F or by the reaction of KOSiMe(3) with LiOSiMe(3). Molecular weight st udies show a partial dissociation to smaller clusters in solution. The mixed alkali metal compounds 1-3, as well as an equimolar mixture of KOSiMe and LiOSiMe(3), serve as unique catalysts for the anion induced ring opening polymerization of octamethylcyclotetrasiloxane in that t hey produce a linear polymer of relatively high molecular weight and l ow polydispersity.