Acta Chim. Slov. 2003, 50, 29-41. 29 REACTIONS OF SULFUR FLUORIDES AND BENZENES IN A LOW TEMPERATURE PLASMA Peter Klampfer, Tomaž Skapin, Bogdan Kralj, Dušan Žigon, Adolf Jesih Jožef Štefan Institute, Jamova 39, 1111 Ljubljana, Slovenia Received 15-10-2002 Abstract Sulfur fluorides SF6, C1SF5 and CF3SF5 were reacted with CsH6, CsHsBr and CsHsCl in a low temperature radio-frequency plasma. Due to the stepwise dissociation of sulfur fluorides, the fluorination of benzenes was observed. In ali reaction products C6H5SF5 was found in minor quantities, and BrC6H4SF5 or CICftSFs along with numerous halogenated benzenes when C6H5Br or CsHsCl were used as reactants, respectively. Introduction The introduction of a pentafluorosulfanyl group, SF5, into organic molecules can substantially change their properties, which makes compounds containing the SF5 group potentially useful in a number of applications.1"6 Incorporating the pentafluorosulfanyl group instead of the trifluoromethyl group into high temperature polyimides may cause these polymers to show enhanced properties such as a lower dielectric constant, greater solubility, increased hydrophobicity, less colour and improved tensile properties.3 In the field of energetic materials the potential application of SF5 containing compounds includes the reduction of shock sensitivity of energetic materials in which the nitro group has been replaced by the pentafluorosulfanyl group.6 The use of pentafluorosulfanylbenzenes has been inhibited by their low yields of production and for this reason many attempts have been made to improve the yields of syntheses and make the compounds available on a large scale. The first to prepare C6H5SF5 was Sheppard7 in 1960. He isolated several pentafluorosulfanylbenzenes by fluorination of aromatic disulfides with AgF2 in CFC 113 at 393 K. Pentafluorosulfanylbenzenes were later prepared by various reactions: by the reaction of S2Fi0 with benzene8 at 453 K, by the reaction of SF5C=CH with 1,3-butadiene,9 by the reaction of SF5C=CH with SF5C1,10 by fluorination of aromatic disulfides in concentrated sulfuric acid,11 by fluorination of aromatic disulfides with elemental fluorine in CH3CN12 (C6H5SF5, 38.5% yield) and by fluorination of P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes ... 30 Acta Chim. Slov. 2003, 50, 29-41. diphenyl disulfide by XeF213'14 (C6H5SF5, 25% yield). The disadvantage of these methods is the low yield of pentafluorosulfanylbenzenes and the presence of impurities which are difficult to separate from the main product. Even though different approaches to synthesis have been used, there were so far no reports on reactions in a plasma, which would yield pentafluorosulfanylbenzenes. However, trifluoromethylbenzene, C6H5CF3 was found to form in a low temperature plasma of gases C6H5Br and C2F6.15 By using reactive CF3 radicals generated in a low temperature plasma from C2F6 gas, numerous organometallic compounds were also prepared.16 Similary, SF5 radicals generated in a plasma would be expected to react with benzenes to produce pentafluorosulfanylbenzenes. The present work was aimed at the plasma chemistry of the sulfur fluorides SF6, CF3SF5, C1SF5 and benzenes, with special emphasis on the formation of pentafluorosulfanylbenzenes in the plasma. Experimental Reagents. Benzene (analytical grade) was obtained from Kemika, C6H5Br (99%) and C6H5C1 (99.9%) from Aldrich. SF6 (99.75%) from Aldrich and CF3SF5 from Flura Corporation were used as received. C1SF5 was prepared by the reaction of SF4, Cl2 and dry CsF in a stainless steel pressure reaction vessel which was gradually heated to 448 K during a 3 hour period and then kept at this temperature for 2 hours.17 C6H5SF5 which was used as a standard sample, was prepared by two different methods.7'14 Apparatus. The source of radio-frequency power was an IEVT VGK 200/1 high frequency generator operating at 27 MHz and at 300 W maximum power. The power dissipated in the plasma reactors was measured by a Zetagi HP 201 SWR through-line wattmeter. Reactions were caried out in a beli jar type quartz reactor described elsewhere18 and in a stainless steel reactor.19 The quartz reactor was a 70 mm o.d., 250 mm long quartz tube, connected on one side by two inlet tubes to gas cylinders with flow regulators, and on the other side to a cold trap held at 77 K, which was evacuated by a diffusion pump. The plasma was inductively coupled through a helical coil, which consisted of seven P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes ... Acta Chim. Slov. 2003, 50, 29-41. 31 turns of 4 mm o.d. copper tubing. The pressure inside the reactor was monitored by an ILM Labor Pirani vacuummeter and the power dissipated in the reactor was 15 W. Stainless steel reactor was an in house constructed modified GEC reference celi19'20 of 200 mm i.d. and 284 mm in height. Gases were supplied to the reactor from gas cylinders and the flow was controlled by MKS 1359 CJ Mass Flow Controllers. The pressure in the reactor was measured by an MKS Baratron pressure meter (0-100 Pa) and by an in-house Alpert gauge high vacuum and ultra high vacuum meter. The plasma in the reactor was inductively coupled through a silica window by a five-turn planar coil of 3 mm diameter21 and the power dissipated in the reactor was 25 W. Methods. Reactions in a low temperature plasma. Prior to reactions in a low temperature plasma, the system (ali quartz or stainless steel) was evacuated to 10"3 Pa and a Dewar flask with liquid nitrogen was placed around the trap. The flow rates of gases were adjusted to the required values. After the flow and pressure stabilized, the plasma was initiated. Reaction products were trapped in the 77 K trap and were subsequently separated on a vacuum line into two fractions: low boiling and high boiling fractions. Low boiling fraction was analysed by FTIR while high boiling fraction was analyzed by GC-MS and by GC-FTIR. Chromatographically separated compounds were identified by comparing the mass spectra and IR spectra of individual components to NIST library mass spectra22 and to Aldrich library FTIR spectra, respectively.23'24 In the quartz reactor sulfur fluorides SF6 and CF3SF5 were reacted with C6H6, C6H5Br and C6H5C1 at a total flow rate of 1 mL min"1 to 11.3 mL min"1 in individual experiments. Reactions of SF6, CF3SF5 and C1SF5 with benzene were performed in the stainless steel reactor at a total flow rate of 7 mL min"1 and argon was added at a flow rate of 1 mL min"1 to the stainless steel reactor only to facilitate the excitation of species in the plasma.25 In the quartz reactor the pressure during reactions was kept at 5 Pa, while in the stainless steel reactor the pressure was varied from 1.4 Pa to 14 Pa in individual experiments. The pressure and the radio-frequency power were kept low due to the extensive polymerization of aromatics that occurred at higher applied pressure and radio-frequency power,26 especially when benzene was used as reactant. P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes 32 Acta Chim. Slov. 2003, 50, 29-41. Degree of dissociation-decomposition of SF6 in plasma. For the production of pentafluorosulfanylbenzenes a high dissociation-decomposition of sulfur fluorides in the plasma, which means a high concentrations of SF5 radicals, is essential. Therefore, the degree of dissociation-decomposition of SF6 in the stainless steel reactor was determined by the online Dupont instruments quadrupole mass spectrometer 21-440 Residual Gas Analyzer (RGA) which was connected to one of the reactor windows and operated at an ionization energy of 70 eV. Scans from m/z 1 to m/z 200 were completed in 15 seconds. Reaction mixtures were sampled through a 0.05 mm orifice. A separate oil diffusion pump maintained the vacuum in the mass spectrometer at 10"4 Pa. The degree of dissociation-decomposition of SF6 gas in a low temperature plasma in a particular stainless steel reactor was determined by the difference mass spectrum which was obtained by recording the mass spectra of SF6 gas in the stainless steel reactor by the online spectrometer when the discharge was on and at essentially the same conditions when the discharge was off, and substracting the spectra.27 Difference mass spectra offer an estimation of the lower and upper limits of the degree of dissociation of the gas in the plasma. Analyses. The direct GC-MS analysis of reaction products trapped at 77 K was carried out on an AutoSpec mass spectrometer (Micromass, Manchester, UK) coupled with an HP 5890 series gas II. chromatograph (Hewlett-Packard, Valdbron, Ge). An HP-5MS 30 m x 0.25 mm fused silica capillary column was used. Splitless injection (splitless duration 60 s) was carried out with an injector temperature of 523 K. The column was held at 323 K during injection and then programmed to the temperature of 473 K at 20 K min"1, and to 523 K at 15 K min"1. The final column temperature of 573 K was reached at 10 K min"1. Helium at a flow rate of 1 mL min"1 was used as carrier gas. The ionization energy was 70 eV and source electron current was 150 µK. Data were acquired in the magnet scan mode using a scan from m/z 50 to m/z 500 with a scan tirne of 0.8 s. GC-FTIR analyses were performed on a Model 8700 gas chromatograph coupled with a GC-IR interface to a 1710 FTIR spectrometer (ali components from Perkin-Elmer). A Perkin-Elmer bonded methyl 5% phenyl silicone 10 m x 0.53 mm fused silica capillary column with 5 µm film thickness was used. Liquid P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes ... Acta Chim. Slov. 2003, 50, 29-41. 33 samples of 1-2 µI were injected into a packed column injector heated to 523 K. The column was held at 313 K for 5 minutes after injection, then programmed to 493 K at 10 K min"1 and held at 493 K for 2-20 minutes. Helium was used as carrier gas. Components were detected by FID or TCD. Throughout the analyses the transfer line to the FTIR spectrometer and the gold coated light-pipe were heated to 513 K. Spectra were taken at 8 cm"1 resolution. Results and disscusion Determination of dissociation-decomposition rate in a plasma of SF6 gas. The concentration of SF5 radicals in a plasma is closely related to the dissociation-decomposition rate of sulfur fluoride gas.28 The differences in the mass spectra obtained with and without operation of the discharge were used to estimate the degree of dissociation-decomposition of SF6 in the discharge.27 Figure 1 shows mass spectra of plasma gases sampled online from the reactor and measured by quadrupole mass spectrometer. The mass spectrum in Figure 1A presents dissociation of SF6 in the reactor when the discharge is off The predominance of SF5+ followed by SF3+ is evident. The mass spectrum observed when the discharge is turned on is shown in Figure 1B. The predominant ion observed at rf discharge conditions is SF2+, which indicates the extensive further stepwise dissociation of sulfur fluoride species SF5. In addition to the main ions SF2+, SF3+ and SF5+ measurable contributions to the total ion current from other ions derived directly or indirectly from SF6, namely SF4+, SF+, F+ and the doubly charged ions SF22+ and SF42+, are evident. A reduction in the relative intensities of the ions SF5+ and SF3+ is observed. The differential mass spectrum in Figure 1C was formed by subtracting the intensity of ion current of products in Figure 1B from the intensity of ion current of products in Figure 1A. The degree of dissociation of SF6 in a stainless steel reactor at a SF6 flow rate of 2.5 P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes 34 Acta Chim. Slov. 2003, 50, 29-41. 4 60 -50- A) SF3+ 89 SF5+ 40- 30- 20-10- r <* < < SF4+ 0- H+ I I I 60 ¦ 50 40 30 20 10 0 20 40 60 80 100 120 20 40 60 80 100 120 20 10 0 -10 -20 -30 -40 -50 -60 , . C) "iT F+ I, S+ 87 I SF2+ 0 20 ' 40 SF^ 1 60 80 SF4^ S -3+ 100 | SF4+ 120 SF5+ m/z Figure 1. Mass spectra of neutral species in SF6 gas sampled at a pressure of 1.4 Pa: A) SF6 gas sampled from the cell without discharge, B) SF6 gas sampled from the cell with discharge on, and C) difference of mass spectra B) and A) where negative values indicate a loss when the plasma is on. The isotope peaks for sulfur containing ions were removed to simplify the spectra. 0 0 P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes Acta Chim. Slov. 2003, 50, 29-41. 35 mL min"1 and at a pressure of 1.4 Pa (Figure 1) was found to be in the range27 from 50% to 60%. Reactions of sulfur fluorides and benzenes. In a low temperature plasma sulfur fluorides SF6 and CF3SF5 were allowed to react with C6H6, C6H5Br and C6H5C1 in the beli jar reactor (Table 1), and reactions of SF6, CF3SF5 and C1SF5 with benzene were performed in the stainless steel reactor (Table 2), while argon was added to the stainless steel reactor only to facilitate the excitation of species in the plasma.25 The composition of low boiling volatile products was determined by GC-MS and GC-FTIR. The GC-MS ion current traces of the condensed extract of the organic compounds from the two reactors are presented in the chromatograms shown in Figures 2 and 3. Mainly halogenated aromatic compounds were identified. Identification of compounds was confirmed by the mass spectra library search and by comparison with pure standards. Some of unknown chromatographic peaks were elucidated by interpretation of the mass spectra of unknowns.29 Aromatic compounds usually exhibit intensive molecular ion and typical fragment ions, which allow interpretation of unknowns. As an illustration the mass spectrum of the target compound C6H5SF5, formed in reaction between CF3SF5 and benzene in a low temperature plasma is shown in Figure 4. Reactions in the ali auartz beli jar reactor. Reaction with the quartz wall was observed in the beli jar reactor when SF6 was used as the source of SF5 radicals; other volatile products determined by IR spectroscopy were SiF4, SOF4 and S02F2 besides unreacted SF6. Less volatile products separated by condensation at 253 K were composed mainly of several classes of halogenated benzenes (Table 1), while pentafluorosulfanylbenzene was determined in traces by GC-MS analysis. SF6 is an extremely stable molecule and its primary bond dissociation energy30 of 420 kJ mol"1 is higher than of other sulfur fluoride primary bond dissociation energies (SF5, 222 kJ mol"1; SF4, 352 kJ mol"1; SF3, 264 kJ mol"1; SF2, 384 kJ mol"1; SF, 340 kJ mol"1).31 Therefore, the energy required to dissociate the SF6 molecule also causes the further stepwise dissociation of sulfur species SF5, and consequently the fluorination of P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes 36 Acta Chim. Slov. 2003, 50, 29-41. Figure 2. Gas chromatogram of reaction products of CF3SF5 with C6H5Cl in a plasma in a quartz reactor (5 mL min-1 of CF3SF5, 5 mL min-1 of C6H6Cl), retention time in minutes of C6H5SF5, 2:40; C6H4ClF, 2:38; ClC6H4CF3, 2:54; C6H3Cl2F, 4:38; C6H4Cl2, 5:22; FC6H4SSCF3, 6:25; ClC6H5SF5, 6:30; ClC6H4SSCF3, 10:13; ClC6H4SSCCl2, 13:22; ClC6H4S3CF3, 13:41; FC6H4SC6H4Cl, 17:20; ClC6H4SC6H4Cl, 19:44. Figure 3. Gas chromatogram of reaction products of CF3SF5 with C6H6 in a plasma in a stainless steel reactor (3 mL min-1 of CF3SF5, 3 mL min-1 of C6H6 and 1 mL min-1 of Ar), retention time of C6H5SF5 is 2:31; FC6H5CF3, 1:36; C6H5CF3, 2:34; C6H5SF3, 2:24; CH3C6H4C2H5, 3:18; C6H5SSCF3, 4:07; C12H7F, 4:57; C4H9C6H4C4H9, 5:48; C6H5C6H5, 6:27. P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes Acta Chim. Slov. 2003, 50, 29-41. 37 Figure 4. Mass spectrum of C6H5SF5 found in the reaction products of CF3SF5 with C6H6 in a plasma. aromatic species is likely to occur. Benzene excited in a plasma undergoes two main reactions: monomolecular decomposition and bimolecular reaction with neutral molecules.32 The latter reaction explains the relatively high amount of biphenyl and halogenated biphenyl derivatives in the reaction products. A plasma containing sulfur fluorides and benzenes together has an extraordinarily complex reaction scheme.26 In the reaction products of CF3SF5 with C6H6 and C6H5Br, C6H5SF5 (Figure 4) was found by GC - MS (Figure 2) in minor quantities estimated at less than 1% of ali products (Table 1). When C6H5C1 was used as reactant, besides C6H5SF5, the chlorinated compound C1C6H4SF5 was also found (Figure 2). In a low temperature plasma the dissociation of CF3SF5 follows different routes. Dissociation into CF3 and SF5 by rupture of the C - S bond (Ediss< 272 kJ mol"1)33 may be the primary process which produces the radicals necessary for the final products C6H5CF3 and C6H5SF5 to be formed. The stepwise dissociation of the SF5 group in CF3SF5 is another probable pathway which may lead to the SCF3 substituted benzenes found in ali reactions where CF3SF5 was a reactant. When using CF3SF5 as reactant common P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes 38 Acta Chim. Slov. 2003, 50, 29-41. features in the composition of the reaction products were minor amounts of halogenated benzenes and greater numbers of compounds found in comparison to reactions with SF6 as reactant. The first may well be explained by different dissociation pathways of CF3SF5 which may not lead to fluorinating species. Table 1. Reaction products obtained in the quartz beli jar reactor Reactants Reaction products SF6 + C6H6 C6H5C6H5, C6H5C2H2C6H5, C6H5C6H4F, C6H5CH3, C6H5C2H5, C6H5SF5 SF6 + C6H5Br C6H5C6H5, C6H5C6H4F, BrC6H4C6H4F, BrC6H4C6H3Br2, C6H4BrF, C6H3BrF2, C6H4BrF, C6H3Br2F, C6H4Br2, C6H5CF3, C6H5SF5 SF6 + C6H5C1 C6H5C6H5, C6H4C1SH, C1C6H4SC6H4C1, C1C6H4SSC6H4C1, C6H5SF5, C6H4C1SF5 CF3SF5 + C6H6 CeHsCeHs, CeHsSCeHs, CeHsCeH^, C6H5CF3, C6H5SCF3, C6H5SSCF3, C6H5SSC6H5, C6H5CF2C6H5, C6H5SF5 CF3SF5 + C6H5Br C6H5F, C6H4F2, C6H3F3, C6H4Br2, C6H4BrF, C6H3BrF2, C6H3Br2F, C6H5CF3, C6H4BrCF3, C6H3Br2CF3, C6H5SF5, C6H4BrSF5, FC6H4SSCF3, BrC6H4SSCF3, BrC6H4SCF3, FC6H4SC6H4F, BrC6H4SC6H4F, BrC6H4SC6H4F, BrC6H4SSC6H4F, BrC6H4SC6H3BrF, S6, S8 CF3SF5 + C6H5C1 C6H4C1F, C6H3C12F, C6H4C12, C1C6H4CF3, FC6H4SSCF3, C1C6H4SSCF3, C1C6H4S3CF3, C6H5SF5, C1C6H4SF5, C1FC6H3SF5, C1C6H4SSCC12F, C1C6H4SSCF3, FC6H4SC6H4C1, C1C6H4SC6H4C1 The greater number of compounds found in reaction mixtures containing CF3SF5 is the consequence of the relatively high stability of the CF3 radical which is reflected in the formation of numerous trifluoromethylated compounds. Nevertheless, the reaction of CF3SF5 and C6H6 produces product with by far the most simple gas chromatogram out of nine, as only one halogen, fluorine, is introduced by the reactants. The P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes Acta Chim. Slov. 2003, 50, 29-41. 39 concentrations of C6H5SF5, C6H5CF3 and biphenyl in the reaction products (Figure 3) were much higher when CF3SF5 was one of reactants. When C1SF5 was used, the number of reaction products increased considerably, due to the chlorination of aromatic species, but the quantity of C6H5SF5 was very low. Reactions in the stainless steel reactor. The reactions of SF6 and benzene in the stainless steel reactor at different flow rates of C6H6, 1 mL min"1 of Ar and 3 mL min"1 of SF6 showed that a higher flow rate of C6H6 causes fewer products to form and in lower quantities. More volatile products le. SiF4, SOF4 and S02F2, along with unreacted SF6 were observed in traces; they originate from reactions of sulfur fluorides with the quartz windows of the stainless steel reactor. Table 2. Reaction products obtained in the stainless steel reactor Reactants Reaction products SF6 + C6H6 CeHsCeHs, OH^FLOH^ OFLČ^FL^ OFLČFLOH^ C6H5CH3, C6H5C2H5, C6H5SF3, S8, C6H5SF5 CF3SF5 + C6H6 CeHsCeHs, C6H5C6H4F, C6H5CF3, C6H5SCF3, C6H4F2, C6H3F2CF3, C6H5SF5 C1SF5 + C6H6 C6H5C6H5, CIC6H4SC6H4CI, C6H4F2, C6H4FC1, C6H5C1, C6H3F2C1, C6H4C1C4H9, C6H5S02C1, C6H5SF5 Again, pentafluorosulfanylbenzene appeared in traces in ali reaction products. An interesting feature is the appearance of FC6H4SF5 in the reaction products at a C6H6 flow rate of 3.5 mL min"1, along with large quantities of biphenyl. Though the concentration of C6H5SF5 in the reaction products proved to depend on the reagents used and on the flow rates of reactants, no attempt was made to improve the yield of C6H5SF5 by optimisation of the experimental conditions. However, it is very likely that the yield would increase dramatically by the use of S2Fi0, the most clean source of SF5 radicals, but this was avoided in the present study due to its extremely high toxicity.34 P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes 40 Acta Chim. Slov. 2003, 50, 29-41. Conclusions Dissociation-decomposition of SF6 gas in a low temperature plasma was determined to be in the range of 50% to 60%. Products of reactions of the sulfur fluorides SF6, CF3SF5 and C1SF5 with C6H5, C6H5Br and C6H5C1 in a low temperature plasma consisted mainly of halogenated benzenes. Pentafluorosulfanylbenzene was found in ali cases in minor quantities but for the preparation of pentafluorosulfanylbenzenes conventional methods are preferred. Acknowledgement The authors are grateful to the Ministry of Education, Science and Šport of Slovenia for providing funding. References and Notes 1. G. L. Gard, C. W. Woolf, US Pat. 3448 121, 1969. 2. W. A. Sheppard, US Pat. 3 219 690, 1965. 3. A. Jesih, A. M. Sipyagin, L. F. Chen, W. D. Hong, J. S. Thrasher, Polymer Prepr. (Am. Chem. Soc, Rev. Polym. Chem) 1993, 34, 383-384. 4. R. J. Terjeson, G. L. Gard, J. Fluorine Chem. 1987, 35, 653-662. 5. R. Winter, G. L. Gard, J. Fluorine Chem. 1994, 66, 109-116. 6. H. Sitzmann, W. H. Gilligan, D. L. Ornellas, J. S. Thrasher, J. Energ. Mat. 1990, 8, 352-374. 7. W. A. Sheppard, J. Am. Chem. Soc. 1960, 82, 4751-4752. 8. H. L. Roberts, J. Chem. Soc. 1962, 3183-3185. 9. T. W. Hoover, D. D. Coffman, J. Org. Chem. 1964, 29, 3567-3572. 10. J. Wessel, H. Hartl, K. Seppelt, Chem. Ber. 1986, 119, 453-463. 11. R. D. Chambers, C. J. Skinner, M. Atherton, J. S. Moilliet, J. Chem. Soc, Chem. Commun. 1995, 19. 12. R. D. Bowden, M. P. Greenhall, J. S. Moilliet, J. Thomson, PCT Int. Appl. WO 97 05,106, 1997. 13. X. Ou, G. M. Bernard, A. F. Janzen, Can. J. Chem. 1997, 75, 1878-1884. 14. X. Ou, A. F. Janzen, J. Fluorine Chem. 2000, 101, 279-283. 15. R. A. Jacob, L. L. Gerchman, T. J. Juhlke, R. J. Lagow, J. Chem. Soc. Chem. Commun. 1979, 128-129. 16. R. J. Lagow, J. A. Morrison, in Advances in Inorganic Chemistiy and Radiochemistiy, Ed. H. J. Emeleus and A. G. Sharpe, Academic Press, New York, 1980, p.177-210. 17. C. W. Tullock, D. D. Coffman, E. L. Muetterties, J. Am. Chem. Soc. 1964, 86, 357-361. 18. R. J. Lagow, L. L. Gerchman, R. A. Jacob, J. A. Morrison, J. Am. Chem. Soc. 1975, 79, 518-522. 19. A. Šmalc, A. Jesih, Institut Jožef Štefan - Delovno poročilo, IJS-DP 7830, 1997. 20. P. J. Hargis Jr., K. E. Greenberg, P. A. Miller, J. B. Gerardo, J. R. Torzvnski, M. E. Riley, G. A. Hebner, J. R. Roberts, J. K. Olthoff, J. R. Whetstone, R. J. Van Brunt, M. A. Sobolewski, H. M. Anderson, M. P. Splichal, J. L. Mock, P. Bletzinger, A. Garscadden, R. A. Gottscho, G. Selwyn, M. Dalvie, J. E. Heidenreich, J. W. Butterbaugh, M. L. Brake, M. L. Passow, J. Pender, A. Lujan, M. E. Elta, D. B. Graves, H. H. Sawin, M. J. Kushner, J. T. Verdeyen, R. Honvath, T. R. Turner, Rev. Sci. Instrum. 1994, 65, 140-154. P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes Acta Chim. Slov. 2003, 50, 29-41. 41 21. P. A. Miller, G. A. Hebner, K. E. Greenberg, P. D. Pochan, B. P. Aragon, Res. Natl. Inst. Stand. Technol. 1995, 100, 427-439. 22. NIST mass spectral libraiy, NIST, Gaithersburg, MD, USA, 2002. 23. B. Schrader, Raman and Infrared Atlas of Organic Compounds, 2nd Ed., VCH, Weinheim, Germany, 1977. 24. C. J. Pouchert, The Aldrich Libraiy of FT-IR Spectra, Ed. 1, Vapour Phase, Vol. 3, Aldrich Chemical Company, Milwaukee, 1989. 25. H. V. Boenig, Plasma Science and Technoogy, Cornell University Press, Ithaca, 1982, p. 70. 26. S. F. Durrant, R. P. Mota, M. A. de Moraes, Thin Solicl Films 1992, 220, 295-302. 27. R. Foest, J. K. Olthoff, R. J. Van Brunt, E. C. Benck, J. R. Roberts, Phys. Rev. E 1996, 54, 1876-1881. 28. R. J. Van Brunt, J. T. Heron, IEEE Trans. Electr. Insul. 1990, 25, 75-94. 29. X. F.W. McLafferty, F. Tureček, Interpretation of Mass Spectra, University Science Books, Mili Walley, USA, 1993. 30. W. Tsang, J. T. Herron, J. Chem. Phys. 1992, 66, 4272-4282. 31. T. Kiang, R. N. Žare, J. Am. Chem. Soc. 1980, 102, 4024-4029. 32. H. Suhr, U. Kiinzel, liebigs Ann. Chem. 1979, 2057-2065. 33. J. E. Huheey, Inorganic Chemistry, Harper & Row, Cambridge, 1983, p. A37. 34. G. H. Cady, In Advances in Inorganic Chemistry and Radiochemistry, Eds. H. J. Emeleus and A. G. Sharpe, Academic Press, New York, 1960, p.105-48. Povzetek Žveplovi fluoridi SF6, ClSF5 in CF3SF5 v nizkotemperaturni radiofrekvenčni plazmi reagirajo s C6H6, C6H5Br in C6H5Cl. Zaradi postopne disociacije žveplovih fluoridov pride do fluoriranja benzenov. V vseh reakcijskih produktih je bil dokazan C6H5SF5 v manjših količinah, v nekaterih tudi BrC6H5SF5 ali ClC6H5SF5, skupaj s številnimi halogeniranimi benzeni, kadar sta bila uporabljena reaktanta C6H5Br ali C6H5Cl. P. Klampfer, T. Skapin, B. Kralj, D. Žigon, A. Jesih: Reactions of sulfur fluorides and benzenes