Industrial monoethylamine (5)

5.

5.

Use Karl Fischer coulometric method or Karl Fischer direct coulometric method to determine the mass fraction of water in the n-propanol solution of an ethylamine (anhydrous) sample , subtract the mass fraction of water in the n-propanol reagent, and calculate one The mass fraction of water in the ethylamine (anhydrous) sample

5.

5.

The water in the monoethylamine n-propanol solution reacts quantitatively with the iodine and sulfur dioxide in the electrolyte.

I ₂ +SO ₂ +H ₂ O→2HI+SO ₃

2I ^-- 2e→I ₂

The number of iodine molecules participating in the reaction is equal to the number of water molecules, and the iodine produced by electrolysis is proportional to the amount of electricity consumed.

5.

Electrolyte: Karl Fischer reagent or the electrolyte used with the Karl Fischer coulometric moisture analyzer (commercially available reagent)

5.

5.

5.

5.

After adding electrolyte, adjust the moisture analyzer to working state according to the instrument manual, and then calibrate according to the requirements of the instrument manual

Use a syringe to weigh 50μL of 5.

5.

The mass fraction of monoethylamine n-propanol solution water w ₆ , the value is expressed in %, calculated according to formula (5):

Where:

m ₂ —The value of the mass of water read, in micrograms (ug);

m ₁ ——The value of the sample mass of ethylamine n-propanol solution, in grams (g)
.

Take the arithmetic mean of the two parallel determination results as the determination result
.
The absolute difference between the two parallel determination results is not more than 0.
02%
.

5.
9.
2.
2 Karl Fischer direct electric quantity method

According to the direct electric quantity method stipulated in GB/T6283-2008
.

Use a syringe to weigh 1.
5g～3g of sample solution B (5.
4.
3.
5) as the monoethylamine n-propanol solution sample m1, accurate to 0.
001g, and analyze to obtain the mass fraction of monoethylamine n-propanol solution water as w6
.

Take the arithmetic mean of the two parallel determination results as the determination result
.
The absolute difference between the two parallel determination results is not more than 0.
02%
.

5.
9.
3 Calculation of water content of monoethylamine (anhydrous)

The mass fraction of monoethylamine (anhydrous) water w ₇ , the value is expressed in %, calculated according to formula (6):

Where:

m ₁ —The value of the mass of the sample of monoethylamine n-propanol solution, in grams (g);

w ₆ —The mass fraction of monoethylamine n-propanol solution water measured in 5.
9.
2 or 5.
9.
3, %;

w _A — mass fraction of water in n-propanol (5.
4.
1), %;

w _c —The mass fraction of monoethylamine of sample solution B (5.
4.
3.
5), %
.

5.
10 Determination of chromaticity

According to the provisions of GB/T3143-1982
.
The monoethylamine (anhydrous) sample is sample solution A (5.
4.
3.
3)
.