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Molecular energetics


A great effort was done during last years to have available and reliable thermochemical data for molecules. Databases were developed, enthalpies of formation and bond dissociation enthalpies were measured, prediction properties enhanced, measuring devices built. During 2016 two main achievements deserve emphasis:

1- The influence of a second chemical function was studied in alkaline metal alkoxides, expecting to promote an effect in the corresponding enthalpy of formation. However, the experience shows that no effect at all is detected and thus raising some new questions on crystalline solid energetics and structure (a paper was sent for publication); the Figure presents the enthalpy of formation of alkoxides as a function of the enthalpy of formation of alcohols. If an effect promoted by the existence of a second chemical function in the alkoxide occurred, the orange points should be clearly out of the line.

2- Dissolution of metals in ionic liquids (work already started in 2015 and proving that the dissolution is concomitant with an oxidation of the metal) presented an unexpected result; if more time is allowed more metal dissolves but from certain point ahead the conductivity of the solution does not increase, raising the question in which form the metal is present in the solution since no deposit was observed (work is under way).

QEf 6


Contact person: João Paulo Leal

Selected papers:

Ligia M. C. Silva , Pedro G. Rosado, Joaquim B. Branco, M. A. Antunes, João P. Leal, Synthesis and Energetics of Na, K, Rb and Cs salts with 1,2-ethanediol and 1,4-butanediol; Journal of Chemical Thermodynamics, 2017, 115, 332-341.

J. Vitorino, J.P.Leal, M. E. Minas da Piedade, Gas phase affinity scales for typical ionic liquid moieties by Cooks kinetic method. ChemPhysChem, 2015, 16, 1969-1977.

J. B. Branco, J. M. Carretas, M. Epple, A. Cruz, A. Pires de Matos, J. P. Leal; Enthalpies of Formation of Europium Alkoxides: What Lessons Can Be Drawn From Them; Journal of Chemical Thermodynamics 2014, 75, 20-24.