Identification and determination of the different types of hydrogen and carbon atoms in the soluble organic matter of the Puertollano oil shale

Abstract

The soluble organic matter of the Puertollano oil shale has been studied by NMR (nuclear magnetic resonance) techniques. The sample was obtained by extractive sonication with carbon disulfide as solvent. 1H and 13C NMR spectra were recorded, the latter by using inverse gated heteronuclear decoupling pulse sequences and chromium(III)-acetylacetonate as relaxation reagent to avoid the NOE (nuclear Overhauser effect). Furthermore, the DEPT NMR pulse sequence (distortionless enhancement by polarization transfer) was used to assign different types of carbon atoms. The study and quantitative determination of the different kinds of hydrogen and carbon atoms present in the sample show that this bitumen is composed mainly of aliphatic hydrocarbons such as linear, polyisoprenoid and cyclic alkanes. There is a smaller contribution from aromatic hydrocarbons of variable structures.