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Química Nova

Print version ISSN 0100-4042On-line version ISSN 1678-7064

Abstract

FARIAS, Robson Fernandes de. Estimative by DSC data of the sublimation enthalpies for ethyleneurea and propyleneurea: some empirical correlations with amides and tioamides. Quím. Nova [online]. 1999, vol.22, n.4, pp.509-511. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40421999000400008.

By using DSC data, the enthaplies of sublimation for ethyleneurea and propyleneurea, are calculated as 84 and 89 kJ mol-1 respectively. Using the vaporization enthalpy values for dimethylethyleneurea and dimethylprophyleneurea, as obtained from literature, the empirical relation: Dcrg Hmo (1)/ Dcrg Hmo (2) = Dlg Hmo (1)/ Dlg Hmo(2) = constant, that relate sublimation or vaporization enthalpies of two different substances and of its methylated derivatives, is obtained. Correlations like that are found to another ureas and thioureas.

Keywords : amides; sublimation enthalpy; vaporization enthalpy.

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