Spectroscopic and thermodynamic study of the H-bonding of olefins onto the isolated hydroxyl of amorphous silica

Abstract

FTIR data are reported concerning the adsorption of ethene, propene, but-1-ene, trans-but-2-ene, cyclohexene and methylcyclohexene on Aerosil outgassed at 800°C. H-bonding is the only process occurring with the four lighter molecules, and a strictly Langmuir-type behaviour is found. With the two heavier species, plain physisorption also takes place, causing the solvation of H-bonded adducts, which are best defined at low coverage. From the intensity of the ν(OH) mode of the free hydroxyls as a function of pressure, the equilibrium constant for the H-bond formation is calculated in different ways, according to the role of physisorption. Several correlations are drawn for Δν(OH) and ΔG°. The contribution of the substituents to the basicity of the double bond as measured by the shift in frequency is discussed, as well as the role of H-bonding and van der Waals forces in dictating the energetics of the interaction.

References

1. M. Allian, E. Borello, P. Ugliengo, G. Spanò and E. Garrone, Langmuir, 1995, 11, 4811.
2. B. Onida, M. Allian, E. Borello, P. Ugliengo and E. Garrone, Langmuir, 1997, 13, 5107.
3. H. Knoezinger, in The H-bond: recent advances in theory and experiment, ed. P. Schuster, G. Zundel and C. Sandorfy, North Holland, Amsterdam, 1976, p. 1269.
4. J. Sauer, P. Ugliengo, E. Garrone and V. R. Saunders, Chem. Rev., 1994, 94, 2095.
5. A. D. Buckingham, A. C. Legon and S. M. Roberts, Principles of molecular recognition, Blackie, Glasgow, 1993.
6. P. Politzer, J. S. Murray, Quantitative treatments of solute/solvent interaction, theoretical and computational chemistry, Elsevier, Amsterdam, 1994, vol. 1.
7. E. Borello, A. Zecchina and M. Castelli, Ann. Chim., 1963, 53, 690.
8. G. Busca, G. Ramis, V. Lorenzelli, A. Janin and J. C. Lavalley, Spectrochim. Acta, 1987, 43A, 489.
9. G. Busca, V. Lorenzelli, G. Ramis, J. Saussey and J. C. Lavalley, J. Mol. Struct., 1992, 267, 315.
10. P. Ugliengo, A. M. Ferrari, A. Zecchina and E. Garrone, J. Phys. Chem., 1996, 100, 3632.
11. (a) CRC Handbook of Chemistry and Physics, ed. Robert C. West, CRC Press, Boca Raton, 1985; (b) S. G. Lias, J. E. Bartmess, J. F. Liebman, J. L. Holmes, R. D. Levin and W. G. Mallard, J. Phys. Chem. Ref. Data, 1988, 17(1) Gas-Phase Ion and Neutral Thermochemistry; (c) D. R. Stull, E. F. Westrum Jr. and G. C. Sinke, The Chemical Thermodynamics of Organic Compounds, John Wiley, New York, 1969; (d) A. G. Harrison, Chemical Ionization Mass Spectroscopy, CRC Press, Boca Raton, 1983.
12. G. C. Pimentel and A. L. McClellan, in The Hydrogen Bond, W. H. Freeman and Co., San Francisco, 1960.
13. A. G. Pelmentschikov and R. A. van Santen, J. Phys. Chem., 1993, 97, 10678.
14. A. D. Buckingham, P. W. Fowler and J. M. Hutson, Chem. Rev., 1988, 88, 963.
15. N. Sheppard, in Hydrogen Bonding, ed. D. Hadzi, Pergamon Press, London, 1959, p. 85.
16. A. C. Legon and D. J. Millen, Acc. Chem. Res., 1987, 20, 39; A. C. Legon, Chem. Soc. Rev., 1990, 19, 197.
17. J. A. Cusumano and M. J. D. Low, J. Catal., 1971, 23, 214.
18. R. Mulliken, J. Am. Chem. Soc., 1952, 74, 811.
19. E. A. Paukshtis and E. N. Yurchenko, React. Kinet. Catal. Lett., 1981, 16, 131.
20. K. Morokuma and K. Kitaura, in Molecular Interactions, ed. H. Ratajczak and W. J. Orville-Thomas, Wiley, Chichester, 1980, vol. 1, p. 21.
21. B. Civalleri, E. Garrone and P. Ugliengo, Langmuir, 1999, 15, 5282.
22. W. Hertl and M. L. Hair, J. Chem. Phys., 1968, 72, 4676.
23. G. Curthoys, V. Ya. Davydov, A. V. Kiselev, S. A. Kiselev and B. V. Kuznetsov, J. Colloid. Interface Sci., 1974, 48, 58.