Activity of some disiloxanes toward the cation exchange resin-catalyst in the siloxane equilibration reaction

The relative activities of four disiloxanes toward the cation exchange resin, which was used as an equilibration catalyst, were determined in such a way that the equilibrium initially present in an arbitrary chosen equilibrate was disturbed by adding the respective disiloxanes to it, and then by recording the viscosity of the equilibrating mixtures as a function of reaction time. As a result, a set of different viscosity-reaction time relationships was obtained, which implies different activities of disiloxanes toward the catalyst. In this way the following decreasing order of acitivites was established: 1,3-tetramethyldisiloxane > 1,3-divinyltetramethyldisiloxane > hexamethyldisiloxane > 1,3-bis(3-carboxypropyl)tetramethyldisiloxane.