Industrial Ethylene Oxide (3)

4.

The mass fraction w _{2 of the} total aldehyde content ( calculated as acetaldehyde ) , the value is expressed in %, calculated according to formula (2):

Where:

V ₁ —The value of the volume of the sample consumed iodine standard titration solution (4.

V ₂ —The value of the volume of the blank consumption iodine standard titration solution (4.

c—The exact value of the concentration of the iodine standard titration solution, the unit is moles per liter (mol/L);

M— The value of the molar mass of acetaldehyde (1/2C ₂ H ₂ O), in grams per mole (g/mol) [M(1/2C ₂ H ₄ O)=22.

V—the value of the volume of the sample, the unit is milliliters (mL);

The value of the density of ethylene oxide at p ₄ —4°C , in grams per milliliter (g/mL) (p ₄ =0.

Take the arithmetic average of the two parallel determination results as the determination result.

4.

According to the regulations of GB/T6283, use a jacketed pipette to pipette laboratory samples

Take the arithmetic average of the two repeated measurement results as the measurement result.

4.

4.

Use phenolphthalein as an indicator to titrate the sample with sodium hydroxide standard titration solution: calculate the acid content in terms of acetic acid based on the volume of the sodium hydroxide standard titration solution consumed .

4.

4.

4.

4.
7.
3 Apparatus

General laboratory equipment
.

4.
7.
4 Analysis steps

Add 70 mL of laboratory samples to a 100 mL graduated cylinder cooled to 0°C to 4°C, and place to volatilize to 50 mL to release possible carbon dioxide
.

Add 0.
2mL to an Erlenmeyer flask containing 40mL of water cooled to 0℃～4℃ on an ice bath
.
Phenolphthalein indicator solution, titrate with sodium hydroxide standard titration solution to reddish color, keep it for 15s without fading, and do not count the reading
.
Pour the sample that volatilized to 50 mL above into the conical flask, titrate it to reddish with sodium hydroxide standard titration solution, and keep it for 15 seconds without fading as the end point
.

4.
7.
5 Result calculation

The acidity is calculated as the mass fraction w ₃ of acetic acid (CH ₃ COOH) , and the value is expressed in %, calculated according to formula (3):

Where:

V ₁ —The value of the volume of the sodium hydroxide standard titration solution (4.
7.
2.
1), in milliliter (mL);

V—The value of the volume of laboratory samples, in milliliters (mL) (Ⅴ=70);

c—The exact value of the concentration of sodium hydroxide standard titration solution, the unit is moles per liter (mol/L);

M—The value of the molar mass of acetic acid, in grams per mole (g/mol) (M ₁ = 60.
1);

The value of the density of ethylene oxide at p ₄ —4°C , in grams per milliliter (g/mL) (p ₄ =0.
891) .

Take the arithmetic average of the two parallel determination results as the determination result
.
The absolute difference between the two parallel determination results is not more than 10% of the arithmetic mean of the two determination values
.

Related Links: Industrial Ethylene Oxide (2)