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Structural Chemistry

, Volume 11, Issue 4, pp 265–269 | Cite as

Paradigms and Paradoxes: Aspects of the Energetics of Carboxylic Acids and Their Anhydrides

  • H. Mark Perks
  • Joel F. Liebman
Article

Abstract

Making use of the enthalpies of formation of the well-established acetic acid and acetic anhydride, the energetics of other carboxylic acid anhydrides (with four or fewer carbons) are discussed. Some of these species are also well known, such as succinic and maleic anhydride. Others are less well known, such as ketene and carbon suboxide and even diatomic carbon and malonic anhydride. Still others are more evasive, such as the classical anhydrides of formic and oxalic acid.

Acetic acid and its anhydride carbon suboxide diatomic carbon enthalpy of formation enthalpy of reaction ketenes and diketenes 

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REFERENCES

  1. 1.
    Pedley, J. B.; Naylor, R. D.; Kirby, S. P. Thermochemical Data of Organic Compounds, 2nd edn., Chapman & Hall: New York, 1986. This volume is the “chosen” archival source of enthalpy of formation data for organic compounds and so an unreferenced datum may be implicitly assumed to arise from this source.Google Scholar
  2. 2.
    Quite inexplicably, the enthalpy of formation of liquid acetic acid is not to be found in the tables of ref. 1. In its absence, we took this value from Wagman, D. D.; Evans, W. H.; Parker, V. B.; Schumm, R. H.; Halow, I.; Bailey, S. M.; Churney, K. L.; Nuttall, R. L. J. Phys. Chem. Ref. Data, 1982, 11 Suppl. 2.Google Scholar
  3. 3.
    Note the word convenient. Consider the series: HX, CH3X, C2H5X, n-C3H7X.... It is well-established that HX is significantly thermochemically distinct from CH3X, and CH3X is from its homolog, C2H5X. On the other hand, C2H5X and n-C3H7X, and subsequent pairs of homologs are much more thermochemically similar. That is, the difference of the enthalpies of formation of HX and CH3X depends strongly on X and the difference of CH3X and C3H5X significantly so, while that of n-C3H7X and C2H5X and their homlogs has a comparatively small dependence on X and on the chain length. (See for the HX/CH3X case, Benson, S. W., Chem. Rev. 1978, 78, 23 and for the more general alkyl X case, see Slayden, S. W.; Liebman, J. F. In Pauling's Legacy: Modern Modelling of the Chemical Bond, Maksićc, Z. B.; Orville-Thomas, W. J., Eds. Elsevier, Amsterdam, 1999, and references cited therein). Nonetheless, there is reason for optimism in our use of acetic acid and its anhydride to provide information about their corresponding formic derivatives: the difference in enthalpies of formation of HC(O)X and CH3C(O)X spans, but a 3 kJ mol-1 range for X c H, OH, and OCH3. The discrepancies are thus relatively benign and will be ignored here.Google Scholar
  4. 4.
    The necessary information is from Chase, M. W., Jr. NIST-JANAF Tables, 4th edn., J. Phys. Chem. Ref. Data Monograph 8, 1998.Google Scholar
  5. 5.
    The 1Σ ground state of C2 is most simply explained by invoking the molecular electron configuration σ1s2σ1s+2σ2s2π2p4.Google Scholar
  6. 6.
    Liebman, J. F. Struct. Chem. 1992, 3, 449.Google Scholar
  7. 7.
    Liebman, J. F.; Skancke, A. Mol. Phys. 1997, 91, 471.Google Scholar
  8. 8.
    Cotton, F. A.; Wilkinson, G. Advanced Inorganic Chemistry, 5th edn., Wiley: New York, 1988.Google Scholar
  9. 9.
    Perrin, C. L.; Arrhenius, T. J. Amer. Chem. Soc. 1978, 100, 5249; Perrin, C. L.; Magde, D.; Berens, S. J.; Roque, J. J. Org. Chem. 1980, 45, 1705.Google Scholar
  10. 10.
    This assertion is a corollary of the reasoning and estimation methodology in Chickos, J. S.; Hyman, A. S.; Liebman, J. F.; Panshin, S. Y. J. Org. Chem. 1988, 55, 3424.Google Scholar
  11. 11.
    Ribeiro da Silva, M. A. J.; Monte, M. J. S.; Ribeiro, J. R. J. Chem. Thermodyn. 1999, 31, 1093.Google Scholar
  12. 12.
    It would appear that maleic anhydride, despite its 4p electrons, is not particularly antiaromatic: this conclusion was also recently deduced in Roux, M. V.; Jiménez, P.; Martin-Luengo, M. A.;Dávalos, J. Z.; Sun, Z.; Hosmane, R. S.; Liebman, J. F. J. Org. Chem. 1997, 62, 2732.Google Scholar
  13. 13.
    Yang, M.-Y.; Pilcher, G. J. Chem. Thermodyn. 1990, 22, 893.Google Scholar
  14. 14.
    Gong, L.; McAllister, M. A.; Tidwell, T. T. J. Amer. Chem. Soc. 1991, 113, 602.Google Scholar

Copyright information

© Plenum Publishing Corporation 2000

Authors and Affiliations

  • H. Mark Perks
    • 1
  • Joel F. Liebman
    • 2
  1. 1.Department of Chemistry and BiochemistryUniversity of Maryland, Baltimore CountyBaltimore
  2. 2.Department of Chemistry and BiochemistryUniversity of Maryland, Baltimore CountyBaltimore

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