Progressively fluorinated

Thus, it is stated, in this model of the ECF process, the physico-chemical properties of the partially fluorinated intermediates - or more precisely, the course of these properties with progressive fluorination - provide the clue to a better understanding of the mechanisms involved. 

In the argument against the ECbECN concept, much, perhaps too much, store has been placed by critics on observations which seem to undermine the zipper mechanism in the apparent belief that this mechanism is axiomatic with the ECbECN as a whole. However, as has been shown, changing physico-chemical properties of progressively fluorinated products inevitably result in different adsorptive forces for these compounds, with possible desorption from the electrode as a consequence this situation could apply equally well with products formed via a carbocation mechanism as with radically generated compounds, even though, as originally stated, the implication is otherwise. 

Figure 11. Effect of progressive fluorination of oj-CH3 group on wettability by n-alkanes [32]...

The importance of jj a p interactions is reflected in the C-C bond shortening and the concomitant C-C BDE increase upon progressive fluorination of one of the ethane carbons (Table 6.1). ... 

Scheme 1.5 Derived mechanism for a progressive fluorination degree (reproduced from [34] by permission of the American Chemical Society)...

R. Konig, G. Scholz and E. Kemnitz, Local structural changes in aluminium isopropoxide fluoride xerogels and solids as consequence of progressive fluorination degree, J. Phys. Chem. C, 113, 6426-6438 (2009). 

Progress in the field received further impetus with the development of synthetic steroids exhibiting activities far greater than that of the natural hormones. The synthesis of 9 a-fluorocortisol (3), described in 1953 by Fried and Sabo (3), opened the way for development of many more highly active antiinflammatory agents, and indeed some of today s most active antiinflammatory agents (ca 1997) bear some resemblance to this 9a-fluorinated steroid. 

Recent Progress in Perfluoroalkylation by Radical Species with Special Reference to the Use of Bis(perfluoroalkanoyl)peroxides Yoshida, M, Kamigata, N J Fluorine Chem 49, 1-20 62 an c -I d... 

In hydroxyUc solvents, the reaction with aniline follows a bi-molecular course but is complicated by competing solvolysis. This is a striking result when compared with the behavior of picryl chloride, which is much more selective with regard to the same reagents (aniline and alcohol), and has been interpreted to mean that bond-breaking has made appreciable progress in the rate-determining step of the reaction of phosphonitrilic chloride. Furthermore, the same indication is obtained from the fact that in the reactions of the halides, the fluorine chlorine ratios are less than one. ... 

An overview is presented of plutonium process chemistry at Rocky Flats and of research in progress to improve plutonium processing operations or to develop new processes. Both pyrochemical and aqueous methods are used to process plutonium metal scrap, oxide, and other residues. The pyrochemical processes currently in production include electrorefining, fluorination, hydriding, molten salt extraction, calcination, and reduction operations. Aqueous processing and waste treatment methods involve nitric acid dissolution, ion exchange, solvent extraction, and precipitation techniques. 

Progress in Organic Fluorine Chemistry, M. Stacey,/. Royal Inst. Chem., 84 (1960) 11-14. 

The fluorination of chromium oxide caused an increase of surface site Lewis acidity. Kemnitz and al.[12] as well as Peri [13], showed that on fluorinated alumina the progressive substitution of F for O and OH led, thanks to inductive attracting effect of fluorine, to an increase of the Lewis acidity of a sites. Hence the dehydrofluorination reaction was ftivoured on strong acide sites. 

More Heavily Fluorinated Compounds. The series of fluo-rinated ethanes in Scheme 3.18 indicates that the fluorine nucleus of a CH2F group is increasingly shielded as the number of P-fluorines increases, unlike the situation observed for an increasing number of P-chlorine substituents (Scheme 3.12). Note that as one accumulates fluorines at the P-position, the three-bond H—F coupling constant becomes progressively smaller. 

Replacing the hydrogens of CF3CH2F with CF3 groups gives the secondary and tertiary fluoride compounds in Scheme 3.18, which absorb at progressively lower field. However, in spite of this, the secondary and tertiary fluorine substituents of these two compounds are the most shielded of any secondary and tertiary fluorines. 

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