Advertisement

Fluxional Behavior of cis-Fe(DMeOPrPE)2(H)2 (DMeOPrPE = 1,2-[bis(dimethoxypropyl)phosphino]ethane); Implications for the Pressure Swing Purification of Natural Gas

  • Susan R. Cooper
  • Bryan P. Nell
  • David R. Tyler
Article
  • 49 Downloads

Abstract

Materials such as trans-Fe(DMeOPrPE)2(X)(H2O)+ (DMeOPrPE = 1,2-[bis(dimethoxypropyl)phosphino]ethane; X = Cl or H) show considerable promise as sorbents for the removal of N2 from natural gas in a pressure swing process. One problem, however, is that in long-term tests these sorbents slowly degrade over a period of many weeks. This study probed the degradation mechanism for the purpose of finding ways to stabilize the sorbents. To investigate the likelihood of degradation initiated by Fe–P bond dissociation, the fluxional behavior of the related cis-Fe(DMeOPrPE)2(H)2 complex was investigated by variable temperature 1P{1H} NMR spectroscopy. Analysis of the spectra gave the following activation parameters for the fluxional process: ΔH = 11.6 kcal/mol and ΔS = −9.2 cal/mol K. These results suggest that Fe–P bond dissociation (20–45 kcal/mol) is not occurring in the fluxional process and by implication that Fe–P bond dissociation is not initiating the decomposition of the trans-Fe(DMeOPrPE)2(X)(H2O)+ sorbents. Consequently, macrocycle ligands may not be the best approach for stabilizing the sorbents, as we have previously proposed. A “tetrahedral jump” mechanism is proposed for the fluxional process in cis-Fe(DMeOPrPE)2(H)2.

Keywords

Pressure-swing absorption Dinitrogen complexes Fluxional molecules NMR spectroscopy 

Notes

Acknowledgements

Acknowledgment is made to the NSF (CHE-1503550) for support of this research. Acknowledgment is also made to the donors of the American Chemical Society Petroleum Research Fund (ACS PRF 53962-ND3).

References

  1. 1.
    J.D. Gilbertson, N.K. Szymczak, J.L. Crossland, W.K. Miller, D.K. Lyon, B.M. Foxman, J. Davis, D.R. Tyler, Inorg Chem 46, 1205 (2007)CrossRefGoogle Scholar
  2. 2.
    B. P. Nell, C. D. Swor, L. N. Zakharov, D. R. Tyler, J. Inorg. Organomet. Polym. Mater. 25, 495 (2015)CrossRefGoogle Scholar
  3. 3.
    A. Finn, Hydrocarb. Eng. 12, 49 (2007)Google Scholar
  4. 4.
    M. Mitariten, Hydrocarb. Eng. 9, 53 (2004)Google Scholar
  5. 5.
    A.J. Kidnay, W.R. Parrish, Fundamentals of natural gas processing. (CRC Press, Boca Raton, 2010)Google Scholar
  6. 6.
    C.G. Balesdent, J.L. Crossland, D.T. Regan, C.T. López, D.R. Tyler, Inorg. Chem. 52, 14178 (2013)CrossRefGoogle Scholar
  7. 7.
    F.A. Cotton, Acc. Chem. Res. 1, 257 (1968)CrossRefGoogle Scholar
  8. 8.
    Kirk Marat SpinWorks 400 Softw. Univ. Manit. Copyr. 2013 (n.d.)Google Scholar
  9. 9.
    D.S. Stephenson, G. Binsch, J. Magn. Reson. 1969–1992 30, 625 (1978)Google Scholar
  10. 10.
    J. Sandstrom, Dynamic NMR spectroscopy. (Academic Press, London, 1982).)Google Scholar
  11. 11.
    J.P. Jesson, P. Meakin, E.L. Muetterties, F.N. Tebbe, J. Am. Chem. Soc. 93, 4701 (1971)CrossRefGoogle Scholar
  12. 12.
    D.G. Gusev, R. Huebener, P. Burger, O. Orama, H. Berke, J. Am. Chem. Soc. 119, 3716 (1997)CrossRefGoogle Scholar
  13. 13.
    M.T. Bautista, E.P. Cappellani, S.D. Drouin, R.H. Morris, C.T. Schweitzer, A. Sella, J. Zubkowski, J. Am. Chem. Soc. 113, 4876 (1991)CrossRefGoogle Scholar
  14. 14.
    O. Gonzalez-Blanco, V. Branchadell, Organometallics 16, 5556 (1997)CrossRefGoogle Scholar
  15. 15.
    L. Luo, S.P. Nolan, Inorg. Chem. 32, 2410 (1993)CrossRefGoogle Scholar
  16. 16.
    L. Luo, S.P. Nolan, Organometallics 11, 3483 (1992)CrossRefGoogle Scholar
  17. 17.
    C. Li, S.P. Nolan, Organometallics 14, 1327 (1995)CrossRefGoogle Scholar
  18. 18.
    J.G. Gordon II, R.H. Holm, J. Am. Chem. Soc. 92, 5319 (1970)CrossRefGoogle Scholar
  19. 19.
    J.C. Bailar Jr., J. Inorg. Nucl. Chem. 8, 165 (1958)CrossRefGoogle Scholar
  20. 20.
    G. Guilera, G.S. McGrady, J.W. Steed, R.P.L. Burchell, P. Sirsch, A.J. Deeming, New J. Chem. 32, 1573 (2008)CrossRefGoogle Scholar
  21. 21.
    G.A. Melson, Coordination chemistry of macrocyclic compounds. (Plenum Press, New York, 1979)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  • Susan R. Cooper
    • 1
  • Bryan P. Nell
    • 1
  • David R. Tyler
    • 1
  1. 1.Department of Chemistry and Biochemistry1253 University of OregonEugeneUSA

Personalised recommendations