Development of Karl Fischer Reagents

II-1. Organic Compounds
1. Hydrocarbons
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Key Points
Hydrocarbons can be measured readily using standard procedures.
Both volumetric and coulometric titration can be used. Moisture content
tends to be very low, however, because of the low water solubility of
hydrocarbons and because of their low water absorption capacity. For
this reason, coulometric titration is suitable.
In the case of volumetric titration, standard dehydrated solvents are
used. Solubility may be inadequate with long-chain hydrocarbons, but
moisture content can be measured through dispersal extraction after
sufficient stirring. Dehydrated solvents formulated for use with oils can
be used to enhance solubility with good effect.
Substances with low moisture content can be measured accurately
using Karl Fischer Reagent SS-Z (or SS) with a low titer.
With coulometric titration, the sample is added directly to the electrolyte
solution (anolyte). Measurement is carried out after dissolution or
dispersal.
In the case of olefins, double bonding may cause interference. using
the electrolyte solution (anolyte), the interference can be lowered.
Examples of substances that can be measured directly:
Ethylene, propylene, butadiene, propane, butane (see the discussion on
industrial LPG in Chapter III: Applications 2, III-1).
Pentane, 2,4-dimethyl pentane, 2,2-methyl pentane, 2,2,4-trimethyl pentane,
octane, 3-methylhexane, decane, octadecane, 2-pentene, dipentene, 1,3pentadiene,
isooctane, cyclopentane, methyl cyclopentane, cyclohexane,
methyl cyclohexane, cyclohexene, benzene, toluene, xylene, ethyl benzene,
mesitylene, styrene, naphthalene, diphenyl, decalin, hexamethyl benzene,
anthracene, phenanthrene