Cationic telomerization of hexamethylcyclotrisiloxane (D3) with silanes containing alkoxy, aryloxy and acyloxy functions bound to silicon
✍ Scribed by M. Ścibiorek; J. Chojnowski
- Book ID
- 103074748
- Publisher
- Elsevier Science
- Year
- 1981
- Tongue
- English
- Weight
- 491 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0014-3057
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✦ Synopsis
The reaction of D 3 with silanes of general tormula R,Si(OZ)4_,(II n = 0, 1,2, 3 (Z alk',l. aryl, acyl) in bulk or in an inert solvent catalysed by a strong protonic acid and in the presence of activator (H20 or ZOH) shows features typical of a telomerization in which telomers are also able to act as telogens. A high yield of the first telomer e.g. R,Si(OZ)3_,--OSi(RI_,--OSi(RIz--OSiIR):--OZ ma~ be obtained when comparable concentrations of D 3 and I are used. The mechanism was studied for the D3 telomerization with Me3SiOC(OICH3. The rate determining step is opening of the D 3 ring b~ the catalyst which is followed by two fast steps, viz heterocondensation and transesterification.