Molar heat capacities of alkanolamines from 299.1 to 397.8 K Group additivity and molecular connectivity analyses

Abstract

The molar heat capacities of 14 alkanolamine compounds have been measured at five separate temperatures in the range 299.1 to 397.8 K. These compounds were monoethanolamine (MEA), monomethylethanolamine (MMEA), dimethylethanolamine (DMEA), monoethylethanolamine (MEEA), diethylethanolamine (DEEA), n-propylethanolamine (n-PEA), diisopropylethanolamine (di-PEA), diethanolamine (DEA), methyldiethanolamine (MDEA), ethyldiethanolamine (EDEA), n-butyldiethanolamine(n-BDEA), tert-butyldiethanolamine (tert-BDEA), triethanolamine (TEA) and 2-amino-2-methylpropan-1-ol (AMP). Molar heat capacities of these compounds show a structural dependence, where the molar heat capacity of one molecule may be considered as the sum of various group contributions. Hence, the reported molar heat capacity data have been used as input to a group additivity analysis that yields estimates of CH₂, OH, NH and N group contributions to molar heat capacities at each investigated temperature. The additivity principle has been explored in more detail by using molecular connectivity indexes to obtain a simple five-term equation that models the molar heat capacities of the investigated alkanolamines over the entire experimental temperature range.

References

1. Kirk-Othmer, Encyclopedia of Chemical Technology, Wiley, New York, 4th edn., 1992, vol. 2.
2. Y. Maham, T. T. Teng, L. G. Hepler and A. E. Mather, J. Solution Chem., 1994, 23, 195.
3. Y. Maham, T. T. Teng, A. E. Mather and L. G. Hepler, Can. J. Chem., 1995, 73, 1514.
4. T. T. Teng, Y. Maham, L. G. Hepler and A. E. Mather, J. Chem. Eng. Data, 1994, 39, 290.
5. A. W. Hakin, M. M. Duke, J. L. Marty and K. E. Preuss, J. Chem. Soc., Faraday Trans., 1994, 90, 2027.
6. L. B. Kier and L. H. Hall, Molecular Connectivity in Structure–Activity Analysis, Wiley, Research Studies Press, Letchworth, 1986.
7. Y. Xu, Ph.D. Thesis, University of Alberta, Edmonton, Alberta, Canada, 1990.
8. Y. Xu and L. G. Hepler, J. Chem. Thermodyn., 1993, 25, 91.
9. E. S. Domalski, W. H. Evans and E. D. Hearing, J. Phys. Chem. Ref. Data, 1984, 13, suppl. no. 1.
10. Selected Values of Properties of Hydrocarbons and Related Compounds, American Petroleum Institute Research Project 44, Thermodynamic Research Center, Texas A&M University, College Station, Texas, 1979, Table 23-2 (1–205), 1.
11. J. F. Messerly, G. B. Guthrie, S. S. Todd and H. L. Finke, J. Chem. Eng. Data, 1967, 12, 338.
12. J.-P. E. Grolier, A. Inglese and E. Wilhelm, J. Chem. Thermodyn., 1984, 16, 67.
13. G. N. Lewis and M. Randall, Thermodynamics, rev. K. S. Pitzer and L. Brewer, McGraw-Hill, New York, 2nd edn., 1961.
14. The Alkanolamines Handbook, The Dow Chemical Company, USA, 1981, 3.
15. J. J. Spitzer, S. K. Suri and R. H. Wood, J. Solution Chem., 1985, 14, 571.
16. S. K. Suri and R. H. Wood, J. Solution Chem., 1986, 15, 705.
17. M. J. Blandamer, J. Burgess, M. R. Cottrell and A. W. Hakin, J. Chem. Soc., Faraday Trans. 1, 1987, 83, 3039.
18. L. Pogliani, J. Phys. Chem., 1993, 97, 6731.