The name is absent

Chapter 5

takes part in the K-F reaction, but also is a good solvent for all the reagents
including water. But methanol can’t dissolve heavy oil components (e.g.
asphaltenes). When diluted bitumen was added to methanol, asphaltenes
precipitated immediately. The precipitation of asphaltenes on Pt electrodes will
interfere with the titration and finally the titrator stops and shows system error
“check electrode”. In this case, the electrodes can be recovered by washing with
toluene and methanol (first toluene then methanol) and restarting the titrator.

Asphaltenes have good solubility in toluene. But toluene itself can’t be used
as solvent for K-F titration (titrator shows system error “check electrode”). The
mixture of methanol and toluene is a potential candidate for K-F titration. It needs
to satisfy two criteria. First the mixture can dissolve diluted bitumen and no
asphaltenes precipitate. Second the mixture will not affect the titration results. For
pure water calibration, there should be no difference using methanol or the
mixture as solvent.

Table 5.3 shows the solubility test of diluted bitumen in toluene-methanol
mixture and also the titer calibration using the mixture. From the table, diluted
bitumen can’t dissolve in toluene-methanol mixture if toluene volume fraction is
smaller than 75%. During titration, titrator shows system error “check electrode”. If
toluene volume fraction is above 75%, bitumen can dissolve in toluene-methanol

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