3.3.3- trifluoropropene, fluorine

Heterogeneous vapor-phase fluorination of a chlorocarbon or chlorohydrocarbon with HP over a supported metal catalyst is an alternative to the hquid phase process. Salts of chromium, nickel, cobalt or iron on an A1P. support are considered viable catalysts in pellet or fluidized powder form. This process can be used to manufacture CPC-11 and CPC-12, but is hampered by the formation of over-fluorinated by-products with Httle to no commercial value. The most effective appHcation for vapor-phase fluorination is where all the halogens are to be replaced by fluorine, as in manufacture of 3,3,3-trifluoropropene [677-21 ] (14) for use in polyfluorosiHcones. 

There is still another situation that leads to second order spectra and this one usually cannot be anticipated. For example, take a look at the proton spectrum of 3,3,3-trifluoropropene in Fig. 2.9. This spectrum is not the simple one that one would expect for a monosubstituted ethylene. However, the second order nature of this spectrum can be understood after examining the fluorine-decoupled spectrum, which is given in Fig. 2.10. The decoupled spectrum displays the expected multiplets from the ABC system, each proton appearing as a doublet of doublets. The second order spectrum seen in Fig. 2.9 derives from the fact that the protons at 5.98 and 5.93 are seen from the 19F frequency as... 

The fluorine NMR spectrum of 3,3,3-trifluoropropene (Fig. 5.11) provides a good example of the doublet observed for the trifluoro-... 

Proton and carbon spectra of 3,3,3-trifluoropropene are provided in Figs. 5.12 and 5.13 as specific examples of such spectra. The proton spectrum is more complicated than one would have expected based on a first-order analysis. However, a fluorine-decoupled spectrum becomes first order, as was depicted and discussed in Chapter 2, Section 2.3.5, Figs. 2.9 and 2.10. 

The use of solvent has also proved to be necessary in the fluorination of 3,3,3-trichloro-l-phenylpropene18 and l-(4-bromophenyl)-3,3,3-trichloropropene19 with antimony(III) fluoride. 3,3,3-Trifluoro-l-phenylpropene and l-(4-bromophenyl)-3,3,3-trifluoropropene are obtained in 80 and 65% yield, respectively, by refluxing the reactants in dioxane for 7 hours. Tarring occurs in the absence of solvent.15... 

Beside these above fluoroolefins, numerous other fluorinated alkenes have been involved in telomerisation. Most of them are unsymmetrical and thus lead to adducts composed of at least two isomers. Among them, vinyl fluoride and 1,1, 1-trifluoropropene have been attempted with various telogens. 

Multitrifluoromethyl-Substituted Alkenes. Spectral data for cis- and trans-l,l,l,4,4,4-hexafluoro-2-butene, and 2-(trifluoromethyl)-3,3,3-trifluoropropene are given in Scheme 5.42 as representative examples of alkenes bearing two CF3 groups. Note the significant shielding of the fluorines of the cis compound versus the trans compound, which has a chemical shift similar to that of 3,3,3-trifluoropropene (-67 ppm). 

Addition of hydrogen halides across the double bond in perfluoropro-pene resembles the addition to 3,3,3-trifluoropropene. Here, too, fluorines drain electrons from the double bond, rendering it electron-poor, which means that electrophilic additions of hydrogen halides are very difficult. Electron density of the double bond is distributed in such a way that the partial negative charge is at the carbon adjacent to the trifluoromethyl group. Consequently, the proton of the hydrogen halides joins... 

The fluorinated ethenes CF2=Cp2, CF2=CFH, CF2=CH2, CF2=CFC1 and CF2=CFBr each form homopolymers in conventional free-radical initiation procedures [220] and it is notable that the heat of polymerisation for tetrafluoroethene is much greater than for ethene [2]. Indeed, tetrafluoroethene and trifluoropropene are relatively dangerous monomers to handle because of the risk of explosive polymerisation. In marked contrast, quite drastic conditions are required in order to form a homopolymer from hexafluoropropene (HFP) [221], although commercially successful copolymers of CF2=CFCF3 with CF2=CF2 (i.e. FEP) and with CF2=CH2 (Viton rubber) have been developed. 

Modification of Chiral Fluorinated Building Block (S)-Trifluoropropene Oxide... 

TFEA. See 2,2,2-Trifluoroethyl acrylate TFE/HFP. See Fluorinated ethylene/propylene TFEM. SeeTrifluoroethyl methacrylate TFP. See 2,2,3,3-Tetrafluoro-1-propanol 3,3,3-TFP. See 3,3,3-Trifluoropropene TGA. See Thioglycolic acid TGA 2. See Diethylene glycol diacrylate TGDDM. See Tetraglycidyl-4,4 -methylene dianiline... 

Interestingly, the hydrocarboxylation of fluorinated olefins [3,3,3-trifluoropropene (TFP) and pentafluorostyrene (PFS)] was realized to form useful fluorinated acids. The palladium complex PdCl2(dppf) [dppf = l,l-bis(diphenylphosphino)ferrocene] in the presence of SnCl2 at 125 °C and at 10 atm CO showed the highest catalytic activity with TFP (yield = 93%, selectivity = 99% in linear acid), and the catalyst PdCl2(dppb) afforded PFS hydrocarboxylation products in excellent yield and selectivity (Eq. 

Related to the decomposition of the compounds FCH2BF2 and CF3BF2 is the nature of the products obtained from reactions between diborane and the fluoroethylenes or 3,3,3-trifluoropropene, as well as the decomposition of dimethyl-l-(trifluoromethyl)ethylboron. Whereas diborane and olefins react to form trialkylboron compounds, tetrafluoroethylene, trifluoroethyl-ene, 1,1-difluoroethylene, and vinyl fluoride all react to yield boron trifluoride, ethylboron difluoride, and diethylboron fluoride as the principal products (49). Similarly, diborane and 3,3,3-trifluoropropene afford many products including 1,1-difluoropropene, 1-fluoropropene, boron trifluoride, w-propylboron difluoride, and 3,3,3-trifluoropropylboron difluoride (50). As with the reactions between diborane and the fluoroethylenes, the nature of these products can be understood in terms of fluorine shifts, as well as addition of B—H linkages to unsaturated molecules. These processes would involve many different molecular species and transformations (49, 50). For example,... 

---