Predicting chemical reactions
Aromatic rings' interactions
Oeiras, 08.10.09
Can we predict if a given chemical reaction occurs spontaneously at a given temperature? Why do some reactions occur and others do not? To answer these questions it is crucial to have information on the energetics of the molecules involved in the reaction – products and reactants. A paper recently published in the Journal of Chemical Thermodynamics describes an effort in that direction.
The energy content of each molecule is usually defined by a quantity called “enthalpy of formation” and can be experimentally determined or computed using quantum chemistry methodologies. The problem is that there are many, many millions of molecules for which the enthalpies of formation are not available and the list increases every day. Therefore, the development of empirical procedures to predict accurate enthalpy of formation data is essential.
Using experimental values from more than 500 compounds, researchers devised a new method for predicting enthalpies of formation for several families of hydrocarbons (alkanes, alkenes, alkynes, polyenes, poly-ynes, cycloalkanes, substituted cycloalkanes, cycloalkenes, substituted cycloalkenes, benzene derivatives, and bi- and polyphenyls). The authors’ ultimate goal is creating a website where the user obtains a reliable estimate of the enthalpy of formation of a molecule simply by drawing its structure and clicking a button.
Original article
The Journal of Chemical Thermodynamics 41 (12)1356-1373
Additivity methods for prediction of thermochemical properties. The Laidler method revisited. 2. Hydrocarbons including substituted cyclic compounds
Rui C. Santos, João P. Leal and José A. Martinho Simões (ITQB)
