| Popis: |
Fluorosilicones of the type, R 3 SiCH 2 CH 2 (CF 2 ) x CH 2 CH 2 SiR 3 where R equals CF 3 CH 2 CH 2 , CH 3 , Cl, and/or H and where x ranges from 1 to 10, were prepared either by the chloroplatinic acid or peroxide-catalyzed addition of appropriate silanes to CH 2 CH(CF 2 ) x CHCH 2 . The addition of CH 2 CH 2 to Y(CF 2 ) x Y, YBr or I, followed by dehydrohalogenation of the resulting YCH 2 CH 2 (CF 2 ) x CH 2 CH 2 Y provided the required dienes. While the free-radical induced addition of CH 2 CH 2 to Br(CF 2 ) 6 Br and BrCH 2 CH 2 (CF 2 ) 6 Br gave a high yield of BrCH 2 CH 2 (CF 2 ) 6 CH 2 CH 2 Br, the addition of CH 2 CH 2 to BrCF 2 CF 2 Br and BrCH 2 CH 2 CF 2 CF 2 Br under indentical conditions resulted in the formation of no more than a trace amount of BrCH 2 CH 2 CF 2 CF 2 CH 2 CH 2 Br. A similar unsuccessful result was obtained in an attempted addition of CH 2 CH 2 to BrCF 2 Br and BrCF 2 CH 2 CH 2 Br, indicating the importance of the chain length of Br(CF 2 ) x Br for the formation of α,ω-diethylene addition products. Although no complication was encountered in the peroxied-catalyzed addition of silane to CH 2 CH(CF 2 ) x CHCH 2 , the chloroplatinic acid induced addition of silane to the dienes yielded the corresponding rearranged mono-addition products, R 3 SiCH 2 CH 2 (CF 2 ) x -1 CFCHCH 3 , in addition to the diadducts, R 3 SiCH 2 CH 2 (CF 2 ) x CH 2 CH 2 SiR 3 . The decomposition of a reversely oriented platinum-olefin or platinum-diene complex without actual formation of the reverse adduct, , is thought to account for the rearranged mono-addition products. |
