Chapter 5
Based on the photomicrographs, the results after second and third steps are
Similarto those of Figs. 5.7 and 5.10 respectively, confirming that the same results
are obtained when the steps are combined as when they are performed
separately. The second step destroys the rag layer but forms an oil-in-water
emulsion. The third step breaks the oil-in-water emulsion. After this three-step
procedure, nearly all of the oil, water and clay solids can be separated.
5.7. Karl Fischertitration of water in diluted bitumen
5.7.1. Introduction
Karl Fischer (K-F) titration is a classic titration method in analytical chemistry
that uses coulometric or volumetric titration to determine trace amounts of water
in a sample. It was invented in 1935 by the German chemist Karl Fischer[10J. K-F
reaction takes place in two steps:
H2O+I2+SO2+3B→2BH+Γ+BSO3 [5.1]
BSO3+ROH → BH+ROSO3 [5.2]
B: base (usually pyridine is used), ROH: Alcohol (usually methanol is used)
Usually the K-F reagent is the mixture of iodine, sulfur dioxide, pyridine and
methanol. All the compounds are in excess amount except iodine. Based on the
consumption of iodine water content can be calculated.
During the titration process, a constant voltage is applied between the two
166