An initial comparison of the interactions of Type I and III kerogens with organic liquids

The swelling of a pair of Type I (Green River and Rundle) kerogens and a Type III (Pittsburgh No. 8 coal) kerogen in a set of organic solvents is compared. Their behavior shows a regular trend with a low O/C Type I kerogen showing no specific interactions, and Type III dominated by specific kerogen-solvent interactions. The less polar low O/C Type I kerogen (Green River) follows regular solution theory and there appear to be no specific intermolecular interactions serving as non-covalent cross-links. The more polar higher O/C Type I kerogen comes close to regular solution behavior, but the data for polar and non-polar liquids are more scattered. There is evidence for specific interactions with hydrogen bonding solvents. The magnitude of the specific interactions is not large. The typical bituminous coal shows good regular solution behavior with non-polar solvents. All other solvents have specific interactions which can strongly enhance swelling. Good hydrogen bond acceptors show large effects. Only solvents which interact specifically can lead to significant swelling of untreated coal.