 PASH in fossil material
Sulfur heterocycles are found in crude oils, fuels, gasoline
and other petroleum related products. Because sulfur is a direct contributor to
SOx emissions and a poison of automotive catalytic converters, severe environmental
legislation has been introduced to reduce the sulfur content of fuels.
Hydrodesulfurization, an important industrial oil refining process, is in many
cases inadequate in reducing overall sulfur in fossil fuels to desired levels
because aromatic sulfur compounds of the PASH type are quite stable whereas aliphatic
sulfur compounds can easily be desulfurized. In particular sterically hindered
polyalkylated dibenzothiophenes show a high resistance to hydrodesulfurization.
It is a highly desirable goal to develop methods for the isolation of polycyclic
aromatic sulfur heterocycles (PASH), including their separation from polycyclic
aromatic hydrocarbons (PAH).
We try to identify sulfur compounds found in desulfurized oil
products which are resistant towards commonly used desulfurization techniques.
To obtain isolated PASH fractions from natural samples, liquid chromatographic
separation methods are optimized and new stationary phases are developed.
Figure 1: Schematic separation of a crude oil into different PASHs according to size of the aromatic ring system.
Our methods include:
High Performance Liquid Chromatography (HPLC)
Ligand Exchange Chromatography (LEC)
Reversed Phase Chromatography (RP-HPLC)
Gas Chromatography (GC) with Atomic Emission and Mass Spectrometric Detection
(GC-AED and GC-MS)
Ultrahigh resolution mass spectrometry (ESI-Orbitrap and FT-ICR)
Involved group members: Johannes Spenner
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