Embodiments of the invention are directed to the preparation of a discrete cyclosiloxane or a discrete mixture of cyclosiloxanes where a dihydroxysilane or dihydroxysiloxane condenses with a dihydrosilane or dihydroxysiloxane in the presence of a Lewis acid catalyst in a reaction phase including a solvent. The introduction of the dihydroxysilane or dihydroxysiloxane and dihydrosilane or dihydroxysiloxane is controlled such that the cyclocondensation occurs in a reaction phase that is dilute in the SiH and SiOH functionality permitting the isolation of the monocyclocondensation adduct in high yield with little higher molecular weight condensation products. In one embodiment of the invention 1,1-diphenyl-3,3,5,5-tetramethylcyclotrisiloxane is prepared in very high yield.
本发明的实施例涉及在溶剂存在的反应相中,二羟基
硅烷或二羟基聚
硅氧烷与二氢基
硅烷或二氢基聚
硅氧烷在
路易斯酸催化剂的存在下缩合,制备离散的环状
硅氧烷或环状
硅氧烷混合物。控制二羟基
硅烷或二羟基聚
硅氧烷和二氢基
硅烷或二氢基聚
硅氧烷的引入,使环缩合发生在稀释SiH和SiOH官能团的反应相中,从而允许高产率地分离单环缩合加合物,并减少高分子量缩合产物。在本发明的一种实施例中,制备了1,1
-二苯基-3,3,5,5-四甲基环三
硅氧烷,并得到了非常高的收率。