- Tetrafluoroethylene telomerization using dibromohaloethanes as telogens
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Carrier mediated telomerization (CMT) between C2F4 and bromochlorofluoroethanes has been evaluated in terms of product distributions arising from CMT and 'normal' telomerization. The effect of parameters like type of initiator and telogen, TFE pressure and temperature on the reaction has been studied. The peroxide initiated telomerization between dibromohaloethanes and C2F4 offers an easy synthetic route to α,ω-dibromo perfluoroalkanes Br(CF2)nBr with n = 2, 4, 6 and 8. The selectivity of the CMT products versus those from "normal" telomerization depends mainly on the choice of telogen and on its ability to act as 'bromine donor' in the radical telomerization. These perfluoroalkyl dibromides are useful intermediates for other derivatives, for example, perfluorinated mono- and diolefins, Br(CF2) nCHCH2 and CH2CH(CF2) nCHCH2.
- Wlassics,Tortelli
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p. 240 - 248
(2007/10/03)
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- INVESTIGATIONS IN THE REGION OF INDUSTRIAL FLUORINATED COMPOUNDS
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The synthesis and properties of ozone-friendly fluorohydrocarbons, fluoroolefins, and fluorinated compounds with functional groups (acids, alcohols, esters, and others), used for the creation of effective surfactants, ion-exchange membranes for various purposes, heat-resistant oils, and greases, were investigated.A technology was developed for the production of highly pure fluorinated compounds for microelectronics, fiber optics, and medicine.
- Maksimov, B. N.
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p. 1935 - 1940
(2007/10/03)
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- KrF laser induced telomerization of bromides with olefins. Part 2. BrC2F4Br and BrC2F4C2H4Br with C2H4 and C2F4
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We investigated the photochemical insertion of one to three olefin units into a CBr bond of two dibromides in gas phase. Unexpected high quantum yields (up to 30) were found in the system BrC2F4Br + C2H4 for the product BrC2F4C4H8C2F4Br and some others. Therefore they cannot be radical combination products, but must arise from chain propagation. To explain their formation, accumulation of C2F4 must be assumed. The addition of ethylene to a radical can be reversed by Br atoms. This reaction strongly influences the product spectrum. Synthesis of BrC2F4C4H8C2F8Br would be economic by the laser method. The preparation of BrC2H4C2F4C2H4Br was also much improved over previous methods.
- Linyang,Fuss,Kompa
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p. 874 - 882
(2007/10/02)
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