HIRANUMA APPLICATION DATA

Karl Fischer Titrator

Watercontents

Data No.

KF5Jun.6.
2017

Ethers and Esters

1. Abstract
Water content of Ethers and Esters are determined by Karl Fischer coulometric titrator. In coulometrictitration, iodine of Karl Fischer reagent is generated by electrolysis and generated iodine quantitatively reacts
with water. Reaction formula is described below.
H2O ＋ I2 ＋ SO2 ＋ 3RN ＋ CH3OH → 2RN・HI ＋ RN・HSO4CH3
2RN・HI → I2 ＋ 2RN ＋ 2H＋ ＋ 2e－Ethers and esters do not interfere the Karl Fischer reaction and direct injection method could apply. Anodesolution is selected from General-use or Oil in accordance with sample solubility. General-use anode solution
contains methanol as solvent. When the sample has low solubility in methanol, the use of anode solution for oil
is appropriate. One exception is a sample containing vinyl group, which reacts with KF reagent and interferes
the titration. When fritless cell is used, cathode solution is not necessary.

2. Apparatus and Reagents(1) Apparatus
Titrator：

Karl Fischer Coulometric titrator

Electrolytic cell：Standard Cell

AQ-2200A

Fritless Cell(2) Reagents
Anode solution：

Hydranal coulomat AG (for general use, nonhalogenated)

Cathode solution：

Hydranal coulomat CG

3. Procedure(1) Fill 100 mL of anode solution and one ampoule of cathode solution into the electrolytic cell as shownin Fig.3.1.
(2) Start blanking to attain stable background.
(3) Wash the syringe with sample.
(4) Draw the sample into syringe and then weigh the syringe.
(5) Inject sample from rubber septum of electrolytic cell as shown in Fig.3.2.
(6) Start titration. Measurement parameter is shown in Table 4.1.
(7) Weigh the syringe again and then set the difference of weight to sample size.

.

Cathode solution

Anode solution

Fig.3.1. Preparation of the reagents.
Note(1) Do not touch the tip of needle toanode solution.
(2) When injecting, set the tip ofneedle as below figure.

(3) Before pulling out the needle,
draw alittleairdripping of sample.

Fig.3.2. Injection of sample.

4. Parameters and results
Table 4.1. Parameters
Condition File
Cal ModeInterval Time
Current
S.TimerBlank Value
Unit Mode
Auto Interval
Minimum Count
Back Ground
Sample Size Input
Cell Type.

0:Sample weight (net)
X=(H2O-BLANK)/SIZE20
SLOW00AUTO
05ON
Every Time
Standard / Fritless

secminuggug

topreventTable 4.2. Results of water content measurement in ethers and esters
SampleSize (g)water(μg)

WatercontentAGCG

2.0827
1.97642.0089

341.4
323.9
329.1

163.9 ppm
163.9
163.8

Fritless

AGStandardAGCG

2.0984
1.9812
1.96490.87971.00071.0423

341.8
323.3
321.9
395.0
449.8
470.4

162.9 ppm
163.2
163.8
449.0 ppm
449.5
451.3

Fritless

AGStandardAGCG0.9985
1.13101.00820.7746
0.78440.8011

451.7
512.8
456.6
567.1
573.4
585.9

452.4 ppm
453.4
452.9
732.1 ppm
731.0
731.4

Fritless

AG

Standard

AGCG

0.83790.91850.85040.34800.52300.3995

608.9
672.9
626.0
330.8
493.2
381.5

726.7 ppm
732.6
736.1
950.6 ppm
943.0
954.9

Fritless

AG

Standard

AGCG

0.44920.57790.55520.9274
1.19304
1.22069

425.1
547.7
525.0
61.2
70.8
72.3

946.3 ppm
947.7
945.6
66.0 ppm
59.3
59.2FritlessAGStandardAGCG

1.135111.103110.814641.278810.90269
1.17183

79.2
70.2
51.3
230.2
159.9
204.3

69.8 ppm
63.6
63.0
180.0 ppm
177.1
174.3

FritlessAG

1.29844
1.27775
1.18092

229.5
224.7
210.5

176.8 ppm
175.9
178.3

SampleApparatus

Cell

Reagent

Anisole

AQ

Standard

Ethyl acetate

Diethyl ether

1,4-dioxane

4-butyrolactone

Propylene carbonate

AQ

AQ

AQ

AQ

AQ

5. Note(1) Use dried syringe and syringe vial for preventive of contamination by atmospheric water.
(2) Put appropriate anode solution in use according to the solubility of the sample. For example, Hydranal
Coulomat AG-H and Oil are suitable for oils.
Note : these reagents does not correspond to Fritless cell.

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