Industrial 1.2-Dichloroethane (3)

4.

The mass percentage (Xi) of each impurity is calculated according to formula (①)

In the formula: m _s -mass of internal standard substance, g;

A _i —the peak area of ​​the component to be tested, mm;

A _s —internal standard peak area, mm;

f _i —the mass correction factor of the impurity component relative to the internal standard;

m—Sample quality: g

The mass percentage of dichloroethane (Xi) is calculated according to formula (2)

X ₁ =100-∑ _{Xi -moisture} .

In the formula: ∑ _Xi — the sum of chromatographic impurity content

Take the arithmetic average of the two parallel determination results as the determination result, and the difference between the two parallel determination results shall not exceed 0.

4.

Carry out according to the provisions of 2.

The difference between the two parallel determination results is not more than 0.

4.

According to GB/T3143 regulations

4.

Carry out in accordance with GB/T2366, and see Appendix C (reference) for test conditions

4.

4.

4.

4.
5.
1.
2 Phenol indicator solution: 10g/L
.

4.
5.
2 Analysis steps

Use a pipette to draw 100 mL of the sample, pour it into the separatory funnel, add 25 mL of distilled water, shake for 1 min, and separate the dichloroethane from the water phase after static layering, and use the same procedure to re-use the separated dichloroethane Wash 2 times, collect 3 times water washing liquid in the same two-corner bottle, add 1 to 2 drops of phenolphthalein indicator solution, and titrate with sodium hydroxide standard titration solution to reddish as the end point
.

4.
5.
3 Calculation and result presentation

The acidity percentage (X ₂ ) is calculated according to formula (3):

Where: V—volume of standard titration solution of sodium hydroxide consumed by titration, mL;

c— The actual concentration of sodium hydroxide standard titration solution, 0.
01mol/L;

p ₂₀ —The density of the sample, g/cm ³ ;

0.
0365—The mass of hydrochloric acid expressed in grams, which is equivalent to 1.
00mL sodium hydroxide standard titration solution [c(NaOH)=1.
000mol/L]
.

Take the arithmetic average of the two parallel determination results as the determination result, and the difference between the two parallel determination results shall not exceed 0.
0001%
.

5 Inspection rules

5.
1 1.
2-Dichloroethane is inspected by the quality inspection department of the manufacturer.
The manufacturer shall ensure that the technical indicators of the products manufactured meet the requirements of this product standard, and attach a certain format of quality certificate.
The content of the certificate includes production Factory name, product name, batch number, production date, product grade and standard number
.

5.
2 When leaving the factory, any number of the same grade is used as a batch, and the sampling method is carried out according to the corresponding content in the fluid in the liquid at room temperature in GB/T6680
.
The number of samples and the amount of samples shall be carried out in accordance with Article 6.
6 of GB/T6678
.
The sampler should also be familiar with and comply with the safety requirements of GB/T3723 related to sampling
.

The total amount of samples to be sampled shall not be less than 500g.
Mix the selected samples and put them into two clean, dry bottles with ground stoppers and label them.
One bottle is for inspection and the other is sealed for future reference.
, The storage period is 2 months
.

5.
3 The inspection result is judged according to the GB/T1250 rounding value comparison method.
When an indicator of the inspection result does not meet the requirements of this standard, double the amount of packaging samples should be re-inspected
.
Even if only one index does not meet the requirements of this standard in the re-inspection result, the whole batch of products is unqualified
.

5.
4 The user has the right to check and accept the product quality in accordance with this standard.
During the storage period, when the supplier and the demander have any objection to the product quality, it shall be raised in time and it shall be settled by both parties through consultation or arbitration shall be requested by the arbitration unit
.

6 Marking, packaging, transportation and storage

6.
1 Each package should be painted with clearly firm name of the manufacturer, site, product name, trademark, product grade, product batch number, production date, number of this standard and product net weight, and should be marked with "flammable liquids" as specified in GB190 "And "drugs" sign
.

6.
2 The product should be packed in dry and clean iron drums (net weight 250kg per drum) or tank trucks
.

6.
3 During transportation, handle with care, avoid contact with hard materials, and avoid sun and rain
.

6.
4 The product is stored in a dry, ventilated, fire-proof and explosion-proof warehouse, and the temperature is kept below 35°C
.
The storage period is 2 months from the date of leaving the factory
.