Distillation process for recovery of hexamethyl disiloxane

摘要

There is disclosed an azeotropic distillation process for separating and recovering hexamethyl disiloxane (HMDO) from toluene in a spent liquor mixture. An HMDO azeotrope former, pyrrolidone, is added to the liquor. The pyrrolidine is added in an amount of at least about 1.81 parts by weight per 1.0 part by weight of HMDO. Preferably, it is added in excess, as about 2.7 to about 5.4 parts by weight of pyrrolidine per 1. 0 part by weight of HMDO. The resulting azeotrope of HMDO and pyrrolidine is then separated by distillation from the liquor. The pyrrolidine may be subsequently recovered from the HMDO by extraction with water. Other HMDO azeotrope formers, such as tertiary butanol, may also be utilized.