Enthalpies and entropies of fusion of ten alkane-α, ω-diamines H2 N– (CH 2)n– NH2 where 3⩽n⩽12

✍ Scribed by Lorenzo Dall’Acqua; ; Giuseppe Della Gatta; ; Bożenna Nowicka; ; Paolo Ferloni

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 205 KB
• Volume: 34
• Category: Article
• ISSN: 0021-9614
• DOI: 10.1006/jcht.2001.0950

✦ Synopsis

Enthalpies fus H m and temperatures T fus of fusion for a homologous series of ten alkane-α, ω-diamines H 2 N-(CH 2 ) n -NH 2 , where n = (3 to 12), were measured by differential scanning calorimetry. Entropies of fusion fus S m were derived from the experimental results. Temperatures of fusion increased as a function of n, and showed a marked odd-even effect with higher values for even terms. The odd-even effect was also observed for molar enthalpies and entropies of fusion as a function of n. Comparison was made with literature values for temperatures, enthalpies, and entropies of fusion of isoelectronic linear alkanes H 3 C-(CH 2 ) n -CH 3 . Results were interpreted on the basis of the literature data on crystal structures of the alkane-α, ω-diamines and their corresponding intermolecular interactions. The fus H m and fus S m interplay provided distinct linear plots for odd and even terms of alkane-α, ω-diamines showing, a common slope value, T fus ≈ 380 K, which was also found for odd and even linear alkanes with n = (6 to 18).