RELEASE OF COVALENTLY-BOUND ALKANE BIOMARKERS IN HIGH YIELDS FROM KEROGEN VIA CATALYTIC HYDROPYROLYSIS

Fixed-bed pyrolysis of kerogens at high hydrogen pressures (>10 MPa, h ydropyrolysis) in the presence of a dispersed sulphided molybdenum cat alyst gives rise to extremely high yields of dichloromethane (DCM)-sol uble oil (>65%). To illustrate the potential of this approach, the yie lds and conformations of the hopanes, steranes and methyl steranes rel eased from Goynuk oil shale (a type I kerogenf by hydropyrolysis after prior sequential extraction of the shale with DCM and pyridine and ba tchwise hydrogenation at 300 degrees C (cf 520 degrees C for hydropyro lysis) are reported here. The total yield of aliphatic hydrocarbons fr om hydropyrolysis represented ca 30% w/w of the kerogen's organic matt er with yields of the C-29-C-32 17 beta(H), 21 beta(H)-hopanes being b etween three and ten times greater than those from DCM extraction and the milder hydrogenation treatment. The yields of the C-33-C-35 17 bet a(H), 21 beta H)-hopanes, not found in the DCM extracts and only minor constituents in normal pyrolysis oil, were again typically at least t hree times higher than from hydrogenation.