21703-43-5Relevant academic research and scientific papers
Kinetics and mechanism of thermal gas-phase oxidation of hexafluoropropene in the presence of trifluoromethylhypofluorite, CF3OF
Dos Santos Afonso,Romano,Della Vedova,Czarnowski
, p. 1393 - 1399 (2000)
The oxidation of hexafluoropropene with molecular oxygen in the presence of CF3OF has been studied at 303.0, 313.0 and 323.4 K, using a conventional static system. The initial pressure of CF3OF was varied between 1.7 and 16.6 Torr, that of C3F6 between 10.0 and 120.2 Torr and that of O2 between 82.0 and 599.8 Torr. Several runs were made in the presence of 325.3-499.2 Torr of N2. Major products were COF2, CF3C(O)F, CF3OC(O)F and a new compound, CF3OCF2OCF2C(O)F. The latter was characterised by the determination of its relative molecular mass and its IR spectrum, which is consistent with the calculated one using theoretical approximations. Small amounts of CF3OCF2C(O)F were also formed. The oxidation is an homogeneous chain reaction, attaining, at the pressure of O2 used, the pseudo-zero-order condition with respect to O2 as a reactant. It is independent of the total pressure. The basic steps are: the thermal generation of CF3O radicals by abstraction of the fluorine atom from CF3OF by C3F6, chain initiation by the addition of CF3O to olefin leading, in the presence of O2, to the formation of haloalkoxy radicals, which decompose via the C-C scission to give products containing C(O)F group and CF3 radicals, reforming CF3O. The full mechanism is postulated.
PROCESS FOR PREPARING HIGH PURITY MONOCARBOXYLIC PERFLUOROPOLYETHERS
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Page/Page column 8, (2009/05/28)
A process for preparing monocarboxylic perfluoropolyethers of formula: A-O-(RF)z-(CFY)t-C(O)OX (I) wherein: X is H, C1-C10 alkyl, or an aryl group; Y=F, CF3; t=1, 2 or 3; A is a C1-C4 perfluoroalkyl end group; z=0 or 1; RF is a perfluorooxyalkylene chain; having a number average molecular weight in the range 180-8,000; comprising the following steps: a) one or more distillations of perfluoropolyethers (PFPE) of formula T-O-(RF)z-T′ (II) wherein: z and RF are as above defined; T, T′, equal to or different from each other, are selected from acyl fluoride or carbonyl-containing functional end groups and non functional end groups to obtain one PFPE fraction of formula (II) wherein the difference between the minimum and the maximum molecular weight of the components is lower than or equal to 600; b) partial fluorination of the fraction obtained in a); c) esterification c1) and/or hydrolysis c2) of the mixture obtained in b); d) distillation of the product obtained in c2) or in c1).
