420-26-8Relevant articles and documents
Fluorination of Alkanes by Chlorine Trifluoride. Hydride Abstraction Mechanism
Brower, K. R.
, p. 798 - 802 (1987)
Addition of chlorine trifluoride to a solution of alkane in Freon or liquid carbon dioxide at -75 deg C gives good yields of monofluoroalkane along with difluoro- and trifluoroalkanes in amounts dependent on reactant proportions.The inorganic products are HF and ClF.The reaction is highly selective for 3 over 2 positions.Methane and hexamethylethane are unreactive.Neohexane fluorinates with rearrangement, but 2-fluoro-3,3-dimethylbutane exposed to the postreaction medium does not rearrange.A hydride abstraction mechanism is inferred.
Steric crowding makes challenging Csp3 - F reductive eliminations feasible
Zhao, Shu-Bin,Becker, Jennifer J.,Gagne, Michel R.
scheme or table, p. 3926 - 3929 (2011/10/03)
A high-yielding fluorination of (triphos)Pt-R+ has been achieved using an array of F+ sources, with XeF2 yielding R-F in minutes. The C-F coupling proved to be a stereoretentive process that proceeds via a concerted reductive elimination from a putative dicationic Pt(IV) center. The larger the steric congestion of the (triphos)Pt-Csp3+ complexes, the more efficient the fluorination, seemingly a result of sterically accelerated C-F reductive elimination along with simultaneous deceleration of its competing processes (β-H elimination).
Fluorination of propane and propene over cobalt(III) trifluoride and potassium tetrafluorocobaltate(III)
Burdon, James,Garnier, Laurent,Powell, Richard L.
, p. 625 - 632 (2007/10/03)
Fluorination of propane and propene over cobalt(III) fluoride and potassium tetrafluorocobaltate(III) gave complex mixtures of products which have been identified to the 0.5percent level.The reactions are valuelles for preparative purposes.The mechanism of the fluorinations is not a simple F-for-H replacement, but requires an initial conversion of propane into propene followed by carbocation- and radical mediated reactions: the carbocations can be quenched by fluoride ions, rearrange and eliminate, and the radicals can be oxidised to carbocations or quenched by fluorine atoms.Radical quenching tends to predominate late in the fluoronation and carbocation reactions at the beginning.
Perfluorination of Allene Derivatives by Direct Fluorination
Arimura, Takashi,Shibakami, Motonari,Tamura, Masanori,Kurosawa, Shigeru,Sekiya, Akira
, p. 588 - 598 (2007/10/02)
Perfluoropropane was prepared from allene with elemental fluorine in the presence of sodium fluoride in 84percent yield for the first time.The reaction of allene with elemental fluorine afforded 2,2-difluoropropane in the absence of sodium fluoride.Methoxyallene and cyanoallene were perfluorinated with elemental fluorine in the presence of sodium fluoride to give heptafluoropropyl trifluoromethyl ether and heptafluoropropyl cyanide in good yields respectively.In addition, the direct fluorination of cyanoallene in the presence of cesium fluoride afforded N,N-difluorononafluorobutylamine in 95percent yield.
Evidence for Carbocation Intermediates in the TiO2-Catalyzed Photochemical Fluorination of Carboxylic Acids
Lai, Cuiwei,Kim, Yeong Il,Wang, Chong Mou,Mallouk, Thomas E.
, p. 1393 - 1399 (2007/10/02)
Laser flash photolysis/transient absorbance spectroscopy was used to determine the mechanism of photo-Kolbe fluorination of carboxylic acids, RCOOH --> RF, at colloidal TiO2 suspensions in acetonitrile.Transient absorption spectra of Ph3C(+), Ph3C(*), Ph2CH(*) and Ph2CH(+) were observed from the photooxidation of Ph3CCOOH and Ph2CHCOOH at TiO2 using 355-nm excitation.Transient decays, monitored in the presence and absence of fluoride ions, showed that the carbocations reacted rapidly with fluoride, but the neutral radicals did not.By varying the laser intensity, it wa s found that the photooxidation of Ph3CCOOH to Ph3C(*) at TiO2 occured via a single-photon process, while the formation of of Ph3C(+) required two photons.This finding is in agreement with the parabolic light intensity dependence of initial reaction rates in bulk photolysis experiments.Although fluoride is strongly adsorbed on the TiO2 surface in acetonitrile solution, the oxidizing power of photogenerated holes could be increased by coordinating HF to F(-), and therefore the threshold for oxidative photochemical fluorination was extented to more positive potentials.In this way less easily oxidized carboxylic acids RCOOH could be converted to RF.
ELECTROCHEMICAL FLUORINATION USING POROUS NICKEL AND FOAM NICKEL ANODES
Drakesmith, F. G.,Hughes, D. A.
, p. 103 - 134 (2007/10/02)
This work set out to examine the reasons behind some of the problems associated with ECF, namely, lack of reproducibility, low chemical yields, poor selectivity and low current densities, with a view to ameliorating these shortcomings and making the process more attractive to the chemical industry.The approach was to study the chemistry under controlled conditions of potential, reactant concentration, temperature, etc., and to analyse the results in terms of product structure, distribution and yield.Two distinct stages in the process were identified, i) the conditioning of the electrode, and, ii) the fluorination of the organic substrate.These stages are described in detail in relation to two model systems investigated, the fluorination of propene using porous and foam nickel anodes, and the fluorination of the octanoyl chloride using nickel foam anodes.The scales of experiments ranged from 100 ml to 100 l cell capacities.General conclusions are derived and recommendations made for the more efficient operation of the process.
