Nitromethane for industrial use (3)

5.

Measure according to the method specified in GB/T3143-1982 (2004)

5.

Measure according to 2.

Nitromethane density correction coefficient for the temperature 0.

5.

Measure according to the method specified in GB/T6283-1986

Take the arithmetic mean of the two parallel determination results as the determination result

5.

5.

Dissolve the sample in a mixed solvent of ethanol and acetone, titrate with potassium hydroxide standard titration solution, and calculate the acidity with the number 9.

5.

5.

5.

5.

5.

5.
7.
3.
1 Acidity meter: 0.
01pH unit with division value
.

5.
7.
3.
2 Magnetic stirrer
.

5.
7.
4 Analysis steps

Warm up the pH meter, and after it stabilizes, calibrate the instrument with sodium tetraborate standard buffer solution to a pH of 9.
18
.
Add 75mL ethanol-acetone solution to a 200mL beaker, use a pipette to draw 25ml laboratory samples into a 200mL beaker, place the beaker on a magnetic stirrer and stir evenly, insert the electrode, and use the potassium hydroxide -ethanol standard titration solution When the titration reaches a reading of 9.
5 to 10.
0, the end point is stable for 30 seconds
.

5.
7.
5 Result calculation

The acidity is the mass fraction w ₂ in terms of acetic acid (C ₂ H ₄ O ₂ ) , and the value is expressed in %, calculated according to formula (2):

Where:

V ₁ —The value of the volume of the potassium hydroxide-ethanol standard titration solution (5.
7.
2.
1) consumed by the sample, in milliliters (mL);

V ₂ —The value of the volume of the potassium hydroxide -ethanol standard titration solution (5.
7.
2.
1) consumed by the blank , in milliliter (mL);

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

25—The value of the sample volume, in milliliters (ml);

p—The value of the density of the sample at the test temperature, in grams per milliliter (g/mL);

M— The value of the molar mass of acetic acid , in grams per mole (g/mol) [M(C ₂ H ₄ O ₂ )=60.
05]
.

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.
005%
.

6 Inspection rules

6.
1 All items specified in Table 1 in the requirements of Chapter 4 are ex-factory inspection items
.
The factory inspection is carried out once per batch
.

6.
2 The amount of nitromethane for industrial use is one batch per finished tank
.

6.
3 The number of sampling units for industrial nitromethane shall be determined in accordance with the provisions of 7.
6.
1 in GB/T6678-2003
.

6.
4 The sampling method of industrial nitromethane shall be carried out in accordance with the provisions of GB/T6680-2003
.
Sampling with an open sampling tube, the sample is evenly mixed, and the samples are divided into two clean and dry ground-mouth bottles.
Labels are attached to indicate the product name, batch number, sampling date, sampling location, and the name of the sampler
.
One bottle is for inspection and one bottle is kept for future reference
.

6.
5 Nitromethane for industrial use shall be inspected by the quality supervision and inspection department of the production plant
.
The manufacturer shall ensure that each batch of products manufactured meets the requirements of this standard
.
Each batch of products should be accompanied by a certificate of quality of certain formats, including: manufacturer name, product name, date of production or batch number, product grades and standard number and so on
.

6.
6 The judgment of the test result shall be carried out according to the rounding value comparison method specified in GB/T1250
.
If one of the inspection results does not meet the requirements of this standard, samples should be taken from twice the number of packaging units for inspection.
Even if only one indicator does not meet the requirements of this standard, the entire batch of products should be downgraded.
Or unqualified processing
.

7 Marking, packaging, transportation and storage

7.
1 Industrial nitromethane packaging containers should have a strong mark, which includes: product name, manufacturer name, factory address, batch number or production date, product grade, net content, number of this standard, and the "specified in GB190-1990" Flammable liquid" sign
.

7.
2 Nitromethane for industrial use should be packaged in clean, dry, airtight plastic drums, or in other containers that can ensure product quality and meet transportation requirements
.
Net weight per barrel is 225kg, or packed according to user requirements
.

7.
3 During the transportation of industrial quercetyl methane, there should be no impact, friction, or drag, and the integrity of the package should be ensured
.

7.
4 Nitromethane for industrial use should be stored in a cool, ventilated, dry place, away from the sun, and isolated from heat and fire
.
Nitromethane for industrial use shall have a shelf life of 8 months from the day it leaves the factory under the storage and transportation requirements specified in this standard
.
It can be re-inspected after the expiry date, and it can still be used if the inspection result meets the requirements of this standard
.

8 Security

8.
1 Nitromethane is toxic, flammable, and acidic.
When operating, wear protective equipment and emergency water sources should be available on site
.
When a fire occurs, foam extinguishing agent, carbon dioxide or water should be used to extinguish the fire
.

8.
2 nitromethane should avoid contact with the base rubber, such as iron
.