J. Chojnowski, and W. Fortuniak, J. Kurjata
May 6, 2006
Citations
2
Influential Citations
49
Citations
Journal
Macromolecules
Abstract
Oligomerization reactions of 1,3-dihydro-1,1,3,3-tetramethyldisiloxane (HMMH) and of 1-hydro-1,1,3,3,3-pentamethyldisiloxane (HMM) catalyzed by tris(pentafluorophenyl)borane were studied. In the presence of this catalyst, HMMH is converted to a series of linear α,ω-dihydrooligodimethylsiloxanes of general formula HSiMe2(OSiMe2)nOSiHMe2 (HMDnMH) and dihydrodimethylsilane (Me2SiH2). In addition to these linear products, cyclic oligodimethylsiloxaneshexamethylcyclotrisiloxane (D3) and octamethylcyclotetrasiloxane (D4)are also formed. The conversion of HMMH follows second-order kinetics to almost full substrate consumption. Trimer 1,5-dihydro-1,1,3,3,5,5-hexamethyltrisiloxane (HMDMH) and dihydrodimethylsilane are formed as primary products. Consecutive reactions of HMMH and the reactions between oligomeric products, i.e., higher oligomers, occur much more slowly. An exception is formation of D3 that is generated from linear tetramer 1,7-dihydrooctamethyltetrasiloxane (HMD2MH) in a fast consecutive reaction. T...