Hydrogenation of fluoroolefins studied by gas phase NMR: A new technique for heterogeneous catalysis

Journal of the American Chemical Society

Volumn 118, Issue 41, 1996, Pages 10000-10001

  Kating, P M ^a   Krusic, P J ^a   Roe, D C ^a   Smart, B E ^a  

^a DUPONT COMPANY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

FLUOROCARBON;

ARTICLE; CATALYSIS; FLUORINATION; NUCLEAR MAGNETIC RESONANCE; REACTION ANALYSIS;

EID: 0029961309     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja961918m     Document Type: Article

References (25)

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3. For reviews, see: (a) Govil, G. Appl. Spectrosc. Rev. 1973, 7, 47. (b) Armstrong, R. L. Magn. Reson. Rev. 1987, 12, 91. (c) Jameson, C. J. Chem. Rev. 1991, 91, 1375.
4. For reviews, see: (a) Govil, G. Appl. Spectrosc. Rev. 1973, 7, 47. (b) Armstrong, R. L. Magn. Reson. Rev. 1987, 12, 91. (c) Jameson, C. J. Chem. Rev. 1991, 91, 1375.
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6. For example, see: (a) Bauer, S. H.; True, N. S. J. Chem. Phys. 1980. 84, 2507. (b) Ross, B. D.; True, N. S. J. Am. Chem. Soc. 1983, 105, 4871. (c) Spring, C. A.; True, N. S. J. Am. Chem. Soc. 1983, 105, 7231. (d) Govil, G.; Clague, A. D. H.; Bernstein, H. J. J. Chem. Phys. 1968, 49, 2821. (e) Harris, R. K.; Rao, R. C. Org. Magn. Reson. 1983, 21, 580. (f) Hirano, T.; Miyajima, T. J. Mol. Struct. 1985, 126, 141.
7. For example, see: (a) Bauer, S. H.; True, N. S. J. Chem. Phys. 1980. 84, 2507. (b) Ross, B. D.; True, N. S. J. Am. Chem. Soc. 1983, 105, 4871. (c) Spring, C. A.; True, N. S. J. Am. Chem. Soc. 1983, 105, 7231. (d) Govil, G.; Clague, A. D. H.; Bernstein, H. J. J. Chem. Phys. 1968, 49, 2821. (e) Harris, R. K.; Rao, R. C. Org. Magn. Reson. 1983, 21, 580. (f) Hirano, T.; Miyajima, T. J. Mol. Struct. 1985, 126, 141.
8. For example, see: (a) Bauer, S. H.; True, N. S. J. Chem. Phys. 1980. 84, 2507. (b) Ross, B. D.; True, N. S. J. Am. Chem. Soc. 1983, 105, 4871. (c) Spring, C. A.; True, N. S. J. Am. Chem. Soc. 1983, 105, 7231. (d) Govil, G.; Clague, A. D. H.; Bernstein, H. J. J. Chem. Phys. 1968, 49, 2821. (e) Harris, R. K.; Rao, R. C. Org. Magn. Reson. 1983, 21, 580. (f) Hirano, T.; Miyajima, T. J. Mol. Struct. 1985, 126, 141.
9. For example, see: (a) Bauer, S. H.; True, N. S. J. Chem. Phys. 1980. 84, 2507. (b) Ross, B. D.; True, N. S. J. Am. Chem. Soc. 1983, 105, 4871. (c) Spring, C. A.; True, N. S. J. Am. Chem. Soc. 1983, 105, 7231. (d) Govil, G.; Clague, A. D. H.; Bernstein, H. J. J. Chem. Phys. 1968, 49, 2821. (e) Harris, R. K.; Rao, R. C. Org. Magn. Reson. 1983, 21, 580. (f) Hirano, T.; Miyajima, T. J. Mol. Struct. 1985, 126, 141.
10. For example, see: (a) Bauer, S. H.; True, N. S. J. Chem. Phys. 1980. 84, 2507. (b) Ross, B. D.; True, N. S. J. Am. Chem. Soc. 1983, 105, 4871. (c) Spring, C. A.; True, N. S. J. Am. Chem. Soc. 1983, 105, 7231. (d) Govil, G.; Clague, A. D. H.; Bernstein, H. J. J. Chem. Phys. 1968, 49, 2821. (e) Harris, R. K.; Rao, R. C. Org. Magn. Reson. 1983, 21, 580. (f) Hirano, T.; Miyajima, T. J. Mol. Struct. 1985, 126, 141.
11. We were able to find only one paper in which NMR was used to study the kinetics of a chemical reaction in the gas phase: Haugh, M. J.; Dalton, D. R. J. Am. Chem. Soc. 1975, 97, 5674.
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19. (b) Rao, V. N. M. In Organofluorine Chemistry: Principles and Commercial Applications; Banks, R. E., Smart, B. E., Tatlow, J. C., Eds.; Plenum Press: New York, 1994.
20. For a review, see for example: Olah, G. A.; Molnar, A. Hydrocarbon Chemistry; Wiley: New York, 1993; pp 446-452.
21. 77k298)/77. The commercial catalyst is 0.5% palladium on γ-alumina beads of 1.6 mm diameter (Engelhard, Inc.) freshly activated with hydrogen and vacuum treatments at elevated temperatures. The ampules are kept in liquid nitrogen until the start of the kinetic experiment. The spectra are recorded with a GE NMR Instruments Omega 360 spectrometer using a SunOS Release 4.03e operating system based on a Sun Sparc-1 computer. No field lock is used, and the ampules are not spun.
22. FF ≈ 290 Hz); C5, -83.7. HFC A: C1, -78.2; C2 and C3, -208.9 and -212.5; C4, overlapping with C4 of HFC B; C5, -83.2 (65 °C).
23. Acquisition time = 57 ms, pulse repetition rate = 157 ms, number of transients = 16, total time for one spectrum = 2.5 s.
24. The initial points obtained when the temperature has not yet equilibrated are discarded. The exponentials do not extrapolate exactly to the starting concentrations at time zero (see starting olefin concentrations on the ordinate axis) presumably because of insufficient diffusional mobility.
25. We are aware of only one study that uses gas phase NMR to study the equilibration of two gases over a solid: Ernst, H.; Kärger, J. Z. Phys, Chem. (Leipzig) 1987, 268, 321.