Persistent Free Radicals in Petroleum

The persistent free radical content in petroleum is of the order 1018 spins/g (1 μmol/g), with higher and lower values found depending on origin different distillation fractions. field radicals was reviewed aim addressing explaining apparent inconsistencies between persistence reactivity. macroscopic average concentration over geological time, but individual species are short-lived reactive. can be explained terms a dynamic reaction equilibrium dissociation association that causes finite number at any given time to present as radicals. Evidence support this description observed changes related change Gibbs energy when bulk liquid properties changed responsiveness temperature. Cage effects, solvent steric protection, stabilization affect rate do not explain petroleum. difference straight-run converted an equilibrated mixture, time. Based limited data available, appear part compositional continuum proposed by Altgelt Boduszynski. Persistent partitioned during classification whole oil, asphaltenes (n-alkane insoluble) fraction having than maltenes soluble) fraction. Attempts relate composition were inconclusive.