Octaphenylcyclotetrasiloxane (OPCTS) is a white solid. It can be used for synthesizing pharmaceutical intermediates and organic silicone intermediates, especially for high temperature resistant phenyl silicone oil and other polymers.
Recrystallise it from AcOH, EtOAc, *C6H6 or *C6H6/EtOH. It forms two stable isomorphs and both forms, as well as the mixture, melt at 200-201o. There is a metastable form which melts at 187-189o. [Burkhard et al. J Am Chem Soc 67 2174 1945, Hyde et al. J Am Chem Soc 69 488 1947, Beilstein 16 IV 1530.]
