Metallopetroporphyrins as process indicators: mass spectral identification of Ni (ETIO) and Ni (DPEP) homologous series in Green River shale oil

reportMass spectrometry (MS) of the porphyrin fraction of a demetallated shale oil from the LLNL Hot-Recycled-Solids retorting process exhibited homologous series of C25 to C33 (C28 maximum) for etio and C26 to C36 (C30 maximum) for DPEP (isocyclic) porphyrins, respectively. The sum of intensities after baseline correction yielded a zDPEP/ietio ratio of 1/1. The petroporphyrin fraction was prepared by demetallation of the whole shale oil using methane sulfonic acid followed by isolation by extraction and purification by alumina chromatography. MS examination of silica purified fractions showed another type of homologous series, tentatively assigned as tetrahydrobenzo-DPEP porphyrin. MS examination of porphyrin fractions isolated by alumina or alumina /silica chromatography without demetallation indicated Ni(etio) and Ni(DPEP) (isocyclic) porphyrins were observed with the same homologous series as seen in the demetallated fraction