The application of computational chemistry to lignin
Computational chemical methods have become an important technique in the examination of the structure and reactivity of lignin. The calculations can be based either on classical or quantum mechanics, with concomitant differences in computational intensity and size restrictions. The current paper will concentrate on results developed from the latter type of calculations for lignin model compounds. These methods can provide information on molecular geometry, thermodynamic properties, kinetics and electronic structure. Using density functional theory, the energies associated with bond dissociation and radical oxidation have been determined for ß-O-4 dimers and trimers, pinoresinols, dibenzodioxocins, catecholalcohol based dimers, spirodienones, and combinations with tricin, catechins and epicatechins. Ongoing work is concerned with homo-coupled ferulates and cross-coupled lignin-ferulates. Exhaustive examinations of stereochemistry reveals the existence of thermodynamic differences with configuration.