Collect. Czech. Chem. Commun. 1979, 44, 542-550

Formation of silenium dication from dimethyldichlorosilane

Miloslav Kučera and Helena Kelblerová

Chemopetrol - Special Purpose Organisation Research Institute of Macromolecular Chemistry, 656 49 Brno


Hydrolysis of dimethyldichlorosilane with water in the presence of HClO4 leads, under certain conditions, to the formation of a defined dication of high initiation efficiency. For the dication formation the initial mixture must contain the excess of hydrolysable Cl- over H+ from water and HClO4. It is described the course of one-step and two-step hydrolysis and the efficiency of low-pressure removal of equilibrium volatiles. The dication formed is characterized by its molecular weight and by the content of ClO4- and Cl-. Infrared and NMR spectra give the evidence that -Si-OH groups are present in the amount of less than 1% of the total Si+ClO4- groups. The initiation efficiency and the dication character of its initiator have been proved by polymerisation tests.