The incipient mesophase formation of 10 narrow cut fractions from Athabasca bitumen vacuum bottoms boiling above 525 °C (pitch) derived by supercritical fluid extraction (extraction) using pentane was performed using hot-stage microscopy. The experiments were performed in a stream of hydrogen at 750 psi (5.2 MPa) and 440 °C. The formation of mesophase for these pitch fractions correlated with their macromolecular carbon residue, molecular weight, and aromaticity. The higher the values of these properties, the sooner the mesophase appeared. The time for the mesophase formation was the shortest in a pitch fraction containing 88 wt % asphaltenes. In cases where the fractions contained low boiling point materials, the mesophase appeared significantly sooner than expected. This was rationalized in terms of the induction period where certain fractions of heavy oils, if present, delay mesophase formation.
Hydrogen is among the emerging energy vectors that are being developed to replace nonrenewable hydrocarbon energy sources. The preferred method to produce hydrogen without generating greenhouse gases is the electrolysis of water using renewable energy. The reduction of energy during the water electrolysis process is a desirable goal regardless of the source of electric power. Similar to ferrous/ferric mediation, iodide can be used as a mediator in the electrolysis of an acidic suspension of coke or coal. The iodide ion is oxidized at a far lower anodic potential than the alternative oxygen evolution reaction. This reduces the cell electrolysis voltage and, consequently, reduces electricity use. The iodide consumed at the anode is continuously regenerated by chemical reaction with the coke/coal in suspension.
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