HG/T 2542-2014Trichloroethylene for industrial use (English PDF)

4.1 Appearance

Transparent liquid, no visible impurities.

4.2 Trichloroethylene for industrial use shall meet the technical requirements shown in

Table 1.

Table 1 - Technical requirements and prepare.

5.7.2.2 Hydrochloric acid standard titration solution: c(HCl)= 0.01mol/L.

When it is required, use 0.1mol/L hydrochloric acid standard titration solution to dilute and prepare.

5.7.2.3 Bromothymol blue indicator solution: 1g/L.

5.7.2.4 Water.

Use 0.01mol/L sodium hydroxide standard titration solution or 0.01mol/L hydrochloric acid standard titration solution to adjust the pH value as 6.6~7.0.

5.7.3 Instruments

5.7.3.1 Micro-burette: 10mL. The division value is 0.01mL.

5.7.3.2 Laboratory routine analytical instruments.

5.7.4 Analysis steps

Use measuring cylinders to respectively measure 50mL of specimen and 100mL of water. Place in a separating funnel. Violently oscillate 3min (about 200 times). After static layering, use a transfer pipette to pipette 50mL of water phase into a triangular flask. Add 5~6 drops of bromothymol blue indicator solution. If the solution is yellow, the solution shall be acidic. If the solution is blue, the solution shall be alkaline. If the solution is green, the solution shall be neutral.

When the solution is acidic: Use sodium hydroxide standard titration solution (5.7.2.1) to titrate till the color turns light blue, which shall be the end point.

When the solution is alkaline: Use hydrochloric acid standard titration solution (5.7.2.2) to titrate till the color turns yellow, which shall be the end point.

When the solution is neutral: Process the solution as acidic.

5.7.5 Result calculation

The mass fraction w1 of acidity (as HCl) or alkalinity (as NaOH) is calculated according to formula (2):

Where,

V1 - The volume of sodium hydroxide (5.7.2.1) or hydrochloric acid (5.7.2.2) standard titration solution consumed by test material, in milliliters (mL);

c - The accurate value of sodium hydroxide or hydrochloric acid standard titration solution concentration, in moles per liter (mol/L);

V2 - The volume of test material, in milliliters (mL);

rhot - The specimen density, in grams per liter (g/mL);

M - The molar mass of sodium hydroxide or hydrochloric acid, in grams per mole (g/moL) [M(NaOH)=40.00, N(HCl)=36.46].

Take the arithmetic mean of two parallel determinations as the report result. The absolute difference of two parallel determinations is not greater than 0.0005%.

5.8 Determination of moisture

5.8.1 Karl Fischer Coulomb Method of Electricity (arbitration method)

5.8.1.1 Reagents

Coulombic coulometric method Karl Fischer reagent (commercially available).

5.8.1.2 Instruments

5.8.1.2.1 Coulomb coulometric moisture analyzer: The accuracy is 0.1µg H2O. The measuring range is 10µg~100mg H2O.

5.8.1.2.2 Balance: The accuracy is 0.01g.

5.8.1.2.3 Air tightness syringe: 1mL.

5.8.1.3 Analysis steps

Use a clean and dry 1mL air tightness syringe to take 1mL of specimen. Weigh it on the balance, to the nearest of 0.01g. Immediately inject the specimen into the Coulometric

Karl Fischer moisture analyzer. Weigh the injector again, to the nearest of 0.01g. Obtain the accurate mass of the injected specimen. Carry out the coulometric titration according to the instrument requirements. Read the water mass from the instrument.

Calculate the moisture content or directly read the moisture content from the instrument.

5.8.2 Karl Fischer Volumetric Method

Carry out according to GB/T 6283.

5.8.3 Tolerance

Take the arithmetic mean of two parallel determinations as the report result. The absolute difference of two parallel determinations is not greater than 0.002%.

5.9 Determination of free chlorine

5.9.1 Method summery

In the acidic medium, free chlorine reacts with potassium iodide to generate free iodine.

When iodine meets starch, it turns blue. The presence or absence of free chlorine is determined by the presence or absence of blue coloration.

5.9.2 Reagents

5.9.2.1 Potassium iodide solution: 100g/L.

5.9.2.2 Acetic acid solution: 1+1.

5.9.2.3 Starch solution: 5g/L.

5.9.3 Analysis steps

Use a transfer pipette to pipette 20mL of specimen into a colorimetric tube. Add 50mL of water. Violently oscillate 3min (about 200 times). After static layering, use a transfer pipette to pipette 20mL of water phase into another colorimetric tube. Add 0.1mL of potassium iodide solution, 1mL of acetic acid solution, 0.1mL of starch solution in sequence. Shake till they are even. Place it still for 5min from light. Observe if blue color appears. It shall be accepted if there is no blue color.

5.10 Determination of acidity after accelerated oxidation test

5.10.1 Method summary

Put steel sheet into the specimen. Access with water and oxygen. Make oxygen saturate.

At the same time, use a light bulb to heat and reflux for 48h. Quantitively pipette the water phase. Use sodium hydroxide standard titration solution to titrate.

5.10.2 Reagents

Oxygen: Volume fraction >=99.9%.

5.10.3 Instruments

5.10.3.1 Ground triangle bottle: 500mL.

5.10.3.2 Ground straight tube condenser: The length is 500mm.

5.10.3.3 Incandescent lamp: 220V, 150W.

5.10.3.4 Stainless steel lampshade: Phi178mm×190mm×1mm.

5.10.3.5 Stainless steel support plate: Phi195mm×6mm, middle hole Phi83mm.

Weigh 200mL of specimen into a 500mL ground triangle bottle. Put sheet A into it.

Cover the end of the oxygen tube with the blow mold tube and insert it into the ground straight tube condenser, 6mm from the bottle bottom. Steel sheet B is tied under the oxygen inlet pipe with Teflon tape (as Figure 1). Then respectively access water and oxygen to the ground triangle bottle. Use the bulb to heat. Adjust the oxygen flow as

10~12 air bubbles per minute. Adjust the water flow to make the sample condensate and reflux at the height below half of the ground tube condenser. Heat and reflux continuously for 48h. Cool to room temperature. Completely shake the solution in the ground triangle bottle. Place it still for static layering. Determine according to 5.7.4.

7.1 Marks

On the packaging container for trichloroethylene for industrial use, there shall be a firm and clear mark, indicating:

a) Product's name;

b) Manufacturer’s name and address;

c) Product batch number or production date;

d) Net content;

e) Reference to this Standard;

f) Marks of "toxic substances" in GB 190 and "Afraid of the sun" in GB/T 191.

7.2 Packaging

According to the storage, transportation, usage or user’s requirements, suitable stabilizer can be added into trichloroethylene for industrial use. When packaging, use clean, dry tank car, tank container or galvanized iron drum, polyvinyl fluoride drum for packaging. Or the conditions that meet the safety requirements, according to user’s requirements, use qualified containers for packaging. The packaging container shall be firm and tight. Before using galvanized iron drum or polyvinyl fluoride drum for packaging, it shall use nitrogen to replace the container. The packaging container shall have at least 5% space.

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