Characterization of medium-temperature Sasol–Lurgi gasifier coal tar pitch

Medium-temperature gasifier pitch (MTP) is only partly soluble in acetonitrile, methanol and ethanol. Single-stage pitch extraction with a large quantity of methanol yielded two liquid phases containing 76 wt.% and 27 wt.% pitch respectively. The pitch fractions recovered from these two phases featured similar aromaticity indices. However, the pitch from the pitch-rich phase had a higher average molar mass and gave an improved carbon yield at 1000 °C. Analysis of the methanol-insoluble pitch fraction showed that methanol extraction at reflux temperatures effectively removed boronic acid model compounds from pitch samples spiked with the same.

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► Medium-temperature gasifier pitch is only partially soluble in methanol.
► This solvent preferentially extracts boron model compounds.
► The extraction residue had a higher molar mass and featured improved carbonization behavior.