Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-27T19:56:55.409Z Has data issue: false hasContentIssue false
  • English
  • Français

The Normal Paraffins Revisited

Published online by Cambridge University Press:  10 January 2013

R. D. Heyding ,
K. E. Russell ,
T. L. Varty  and
D. St-Cyr
R. D. Heyding
Affiliation:
Department of Chemistry, Queen's University, Kingston, Ontario, Canada
K. E. Russell
Affiliation:
Department of Chemistry, Queen's University, Kingston, Ontario, Canada
T. L. Varty
Affiliation:
Department of Chemistry, Queen's University, Kingston, Ontario, Canada
D. St-Cyr
Affiliation:
Research Centre, Du Pont Canada Inc., Kingston, Ontario, Canada
Get access Rights & Permissions [Opens in a new window]

Extract

The low temperature modifications of the normal paraffins n-CnH2n+2crystallize in three groups (Broadhurst, 1962). The structure is triclinic for n even, 6 < n < 26 (Muller and Lonsdale, 1948; Nyburg and Luth, 1972); orthorhombic for n odd, 11 < n < 39 (Smith, 1953; Teare, 1959); and monoclinic for n even, 28 < n < 36 (Shearer and Vand, 1956). In all of these structures the hydrocarbon chains are linear and in trans configuration. The chains are parallel to one another, the terminal methyl groups forming the surfaces of lamella which are more or less perpendicular to the chain axis. For n < ca.36, it is apparently the interlamellar interaction between end methyl groups which dictates the symmetry. For longer chains the structure is usually orthorhombic and comparable to the structure of highly crystalline polyethylenes. Chains do not fold (as they undoubtedly do in polyethylenes) unless n is greater than 102 (Bidd and Whiting, 1985; Ungar and Keller, 1986).

The several crystal forms differ in the manner in which the nearest neighbor chains are related to one another. In the triclinic lattices the packing is such that a triclinic sublattice containing one methylene group is evident. In the other modifications the sublattice is orthorhombic and contains four methylene groups. If the overall symmetry is orthorhombic the long chain axes are perpendicular to the interlamellar surface; the x and y translations, perpendicular to the long axis, are common to both cells. If the nearest neighbor chains are displaced by two or four methylene groups along the chain axis, overall monoclinic symmetry results (Sullivan and Weeks (1970)).

Type
Research Article
Information
Powder Diffraction , Volume 5 , Issue 2 , June 1990 , pp. 93 - 100
Copyright
Copyright © Cambridge University Press 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Appleman, D.E., and Evans, H.T.(1973). U.S. Geol. Survey Computer Contribution 20. U.S. Natl. Tech. Information Service DocPB2-16188.Google Scholar
Asano, T.(1983). Polymer Bull.(Berlin), 10, 547.CrossRefGoogle Scholar
Bidd, I.L., and Whiting, M.C.(1985). J. Chem. Soc, Chem. Comm., 543.Google Scholar
Broadhurst, M.G.(1962). J. Res. Nat. Bur. Stand. 66A, 241.CrossRefGoogle Scholar
Bunn, C.W.(1939). Trans. Faraday Soc. 35, 482.CrossRefGoogle Scholar
Denicolo, I., Doucet, J., and Craievich, A.F.(1983). J. Chem. Phys. 78, 1465.CrossRefGoogle Scholar
Doucet, J., Denicolo, I., Craievich, A., and Collet, A.(1981). J. Chem. Phys., 75, 5125.CrossRefGoogle Scholar
Doucet, J., Denicolo, I., Craievich, A., and Germain, C., (1984) J. Chem. Phys., 80, 1647.CrossRefGoogle Scholar
Doucet, J.and Dianoux, A.J., (1984). J. Chem. Phys. 81, 5043.CrossRefGoogle Scholar
Ewan, B., Strobl, G.R., and Richter, D., (1980). Faraday Discuss. Chem. Soc., 69, 19.CrossRefGoogle Scholar
Gabe, E.J., and Gainsford, G.(1982). Division of Chemistry, National Research Council of Canada. Private Communication.Google Scholar
Jones, R.N., and Pitha, J.(1976). Computer Programs for Infrared Spectrophotometry. Chap. X. National Research Council of Canada, Bulletin 12. 2ndEd.Google Scholar
Kelusky, E.C., Smith, I.C.P., Elliger, C.A., and Cameron, D.G.(1984). J. Am. Chem. Soc., 106, 2267.CrossRefGoogle Scholar
Maroncelli, M., Strauss, H.L., and Snyder, R.G., (1985). J. Chem. Phys. 52, 2811.CrossRefGoogle Scholar
Nakamura, T., Sameshima, K., Okunaga, K., Yoshitaka, S., and Sato, J.(1989). Powder Diffraction, 4, 9.CrossRefGoogle Scholar
Nyburg, S.C., and Luth, H.(1972). Acta Crystallog. B28, 2992.CrossRefGoogle Scholar
Nyburg, S.C., Pickard, F.M., and Norman, N.(1976). Acta Cryslallogr., B32, 2289.CrossRefGoogle Scholar
Nyburg, S.C., and Potworowski, J.A., (1973). Acta Crystallogr., B29, 347.CrossRefGoogle Scholar
Shearer, H.M.M., and Vand, V.(1956). Acta Crystallogr., 9, 379.CrossRefGoogle Scholar
Smith, A.E.(1953). J. Chem. Phys., 21, 2229.CrossRefGoogle Scholar
Strobl, G., Ewan, B., Fischer, E.W., and Piesczek, W., (1974). J. Chem. Phys., 61, 5257. (See also Strobl et al.(1980), Faraday Discuss. Chem. Soc. 69, 19, and papers cited therein.)CrossRefGoogle Scholar
Teare, P.W.(1959). Acta Cryslallogr., 12, 294.CrossRefGoogle Scholar
Ungar, G.(1983). J. Phys. Chem., 83, 689.CrossRefGoogle Scholar
Ungar, G., and Keller, A.(1986). Polymer 27, 1835.CrossRefGoogle Scholar