THERMODYNAMIC CALCULATIONS ON ALKYLATED PHENANTHRENES - GEOCHEMICAL APPLICATIONS TO MATURITY AND ORIGIN OF HYDROCARBONS

Enthalpies of formation of alkylated phenanthrenes have been evaluated by molecular mechanics method. These thermodynamic data have been successfully applied as predictive tools in the case of a highly complex class of compounds, the trimethylphenanthrenes, in order to restrict the synthesis work- of standards to isomers that are likely to be present in natural samples. The changes in the distributions of isomers at different maturity stages are broadly in agreement with these theoretical calculations.