Development of Karl Fischer Reagents
Development of Karl Fischer Reagents
Development of Karl Fischer Reagents
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II-1 Organic Compounds<br />
[Examples <strong>of</strong> Measurement]<br />
(1) Volumetric titration<br />
<strong>Reagents</strong> used:<strong>Karl</strong> <strong>Fischer</strong> Reagent SS<br />
Dehydrated Solvent MS + SO2/pyridine solvent 25-50ml<br />
106<br />
Substance<br />
Potassium dichloroisocyanurate<br />
p-Toluene sulfonyl chloride<br />
p-Chlorobenzene sulfonyl chloride<br />
Toluene 2,4-disulfonyl chloride<br />
p-Ethylbenzene sulfonyl chloride<br />
Methanesulfonyl chloride<br />
*: Drying method 0.23%<br />
**: Infrared method 0.14%<br />
19. Quinones<br />
Key Points<br />
Sample quantity<br />
(g)<br />
1.0228<br />
1.0541<br />
1.0059<br />
0.8721<br />
1.6708<br />
2.9444<br />
Measurement value<br />
(mg)<br />
2.45<br />
0.82<br />
1.20<br />
2.18<br />
0.54<br />
2.10<br />
Moisture Content<br />
(%)<br />
0.24*<br />
0.078<br />
0.12**<br />
0.25<br />
0.032<br />
0.071<br />
Quinones interfere with the titration through the oxidation <strong>of</strong> hydriodic<br />
acid, which is produced from a reaction between water and <strong>Karl</strong><br />
<strong>Fischer</strong> reagent, to produce free iodine. For this reason, direct titration<br />
is impossible. Instead, an indirect method based on water vaporization<br />
is used.<br />
Either volumetric or coulometric <strong>Karl</strong> <strong>Fischer</strong> titration can be used. Refer<br />
to the section on Basic Knowledge for information on the water<br />
vaporization method.<br />
[Examples <strong>of</strong> Measurement]<br />
(1) Water vaporization - Volumetric titration<br />
<strong>Reagents</strong> used: <strong>Karl</strong> <strong>Fischer</strong> Reagent SS-Z (or SS)<br />
Dehydrated Solvent GEX (or MS) + PG (3:1) 50-100ml<br />
Substance<br />
Naphthoquinone (wet)<br />
Naphthoquinone (dry)<br />
p-Quinone<br />
Heating<br />
temperature ( � C)<br />
160<br />
160<br />
130<br />
Sample<br />
quantity (g)<br />
0.1185<br />
2.2096<br />
3.5710<br />
Measurement<br />
value (mg)<br />
7.62<br />
0.82<br />
0.15<br />
Moisture<br />
content (%)<br />
6.43<br />
0.037<br />
0.0042
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