Mercuric Fluoride, a New Fluorinating Agent

Abstract

mation or are at least considerably retarded after the CHsCl group has been "stabilized" by the presence of the two fluorine atoms on the adjacent carbon. The use of mercuric3 fluoride supplied the needed demonstration.This salt fluorinates C2H5CI easily but affects CH2CICHCIF very little, and CH2CICHF2 not at all. Similarly, it reacts quantitatively with C2H6Br, but not at all with CH2BrCHF2; it reacts violently with C2H5I but to affect CH2ICHF2, it must be heated for a long time at 160°, and yields only some 60% of CH2-FCHF2. It cannot be held that mercuric fluoride causes fluorination to proceed along different lines, as it reacts with CHBr8CHBr2 to yield successively CHBrsCHBrF -> CHBr2CHF2 (where the reaction stops when using SbF3), then CHBrFCHF2 -CHF2CHF2 while its reaction with CH2Br-CHBr2 yields successively CH2BrCHBrF and CH2BrCHF2, where the reaction stops just as it does with antimony fluoride.The fluorination of CH3CC13 gives successivelyThere is one other example of fiuorinating directly to a CF3 group, and that is C6H6CC13 -> C6H5-CF3. In both cases, the passage from the CC1F2 stage to the CF3 stage is rapid, an indication that the last chlorine had not been rendered inert by the two fluorine atoms. It should be noted that in both cases there is no halogen atom on the adjacent carbon.The "stabilization" hypothesis is in good agreement with experimental evidence derived from the interaction of fluorochlorides and zinc in (3) See following paper, This Journal, 88, 884 (1936). alcohol. From CC12FCC13, CC12FCCI2F, CHC12-CC12F, CH2C1CHC1F, CHC12CHC1F and CH2C1CC12F, it is extremely easy quantitatively to obtain CC1F=CC12, CC1F=CC1F, CHC1= CC1F, CH2=CHF, CHC1=CHF and CH2= CC1F, respectively. It is, however, quite difficult to obtain CC1F=CF2, CH^HF, CHC1= CHF and CH2=CF2, from CC12FCC1F2, CH2C1-CHF2, CHC12CHF2 and CH2C1CC1F2, respectively, and the yields are not good. It is almost impossible to obtain CF2=CF2 from CF2C1CF2C1, and even at 1000 pounds pressure, the yield is only 30-35%. Summing up the above observations the con-

Synthesis and Vibrational Spectroscopy of 1,1,2,2-Tetrafluoroethane and Its 13C2 and d2 Isotopomers

“…For ν 8 , which is strongly supported by a polarized Raman feature of medium intensity at 412 cm -1 , Kalasinsky et al also assigned this mode to a Q-branch feature at 408 cm -1 in the infrared spectrum. Given the prediction of a weak intensity for the infrared transition for ν 8 and its near coincidence with the intense and complex band for ν 18 for the 4: Vibrational Fundamentals of the Gauche Rotamers of TFEA and its 13 C 2 and d 2 Isotopomers (in cm -1 ) normal species 13 anti rotamer, we think it unlikely that the feature of medium intensity is due to ν 8 of the gauche rotamer. Similar reasoning rules out observing a band for ν 9 in the infrared spectrum, although this mode is represented by a polarized band at 257 cm -1 in the Raman spectrum.…”

“…For ν 18 , as for the gauche rotamers of the other two isotopomers, we interpret the broad shoulder in the infrared spectrum at about 240 cm -1 and a weak depolarized band in the Raman spectrum at 240 cm -1 as evidence for ν 18 . A very weak, apparently depolarized Raman band at about 991 cm -1 is a possibility for ν 13 . The weak feature at 980 cm -1 remains at -100°C and thus is assigned to a combination tone of the anti rotamer.…”

Fluorocarbon Refrigerants and their Syntheses: Past to Present

“…It is worthwhile noting that HgF 2 still follows the same empirical reactivity order as shown in the SbF 3 reactions mentioned previously. HgF 2 is a stronger fluorinating agent than SbF 3 , as described by Henne and Midgley in the paper directly following their presently discussed study and is capable of converting methyl chloroform fully to methyl fluoroform (HFC- 143a ). α,α,α-Trichlorotoluene also converts cleanly to α,α,α-trifluorotoluene, indicating that the stabilization in CF 2 Cl imparted by the two fluorine atoms is overcome by the reactivity of the benzylic C–Cl bond.…”

Preparation of Chlorofluorocarbons - Fluorination of Prins-type condensation products

“…The copper-bronze condensation of trifluorotrichloroethane (Equation 4) gave, in about 50% yield, a high boiling mixture of products in which the ratio of carbon, fluorine, and chlorine atoms was about 8 to 7 to 1: CFC1'-CF-C> 160-C220-C* condensate boiling above 200 °C. (4) PRELIMINARY HYDROFLUORINATION…”