GB/T 33386-20162,3,3,3-Tetrafluoropropene(HFO-1234yf) for industrial use (English PDF)

4.1 Appearance

Place the liquid-phase sample in a 50 mL dry colorimetric tube. When the liquid-phase volume of the sample is about 10 mL, use a dry cloth to dry the frost or moisture that is attached to the outer wall of the colorimetric tube; observe the color of the sample, whether it's turbid or not and whether there is solid particle or not, in a lateral perspective.

4.2 Determination of the content of 2,3,3-tetrafluoropropene

4.2.5.1.4 Calculation of the content of each impurity component in the calibration standard sample The mass fraction wi of the impurity component i in the calibration standard sample is calculated according to Formula (2): […]

4.2.1 Method summary

Use gas chromatography; under the selected chromatographic conditions, the sample passes through the column after vaporization, which separates the components; use hydrogen flame ionization detector (FID) to detect; use compensating area normalization method to calculate the content of 2,3,3,3-tetrafluoropropene.

4.2.2 Reagents

4.2.2.2 Hydrogen: the volume fraction is greater than 99.995%

4.2.2.1 Nitrogen: the volume fraction is greater than 99.995%

4.2.2.4 Air: it is dried and purified by silica gel or molecular sieve.

4.2.2.3 Helium: the volume fraction is greater than 99.995%

4.2.3 Instruments

4.2.3.1 Gas chromatograph: it is equipped with hydrogen flame ionization detector (FID). Take benzene as the sample; the overall sensitivity requires the detection-limit D <= 1 x 10-11 g/s; the stability shall meet the requirements of GB/T 9722; the linear range shall meet the analysis requirements.

4.2.3.2 Recorder: chromatographic workstation or chromatographic data processor.

4.2.3.3 Sampling cylinder: double-valve small cylinder, of which the volume is not less than 150 mL, and the working pressure shall be greater than the pressure of the same product.

4.2.5.1.3 Preparation of the calibration standard sample

According to the pressure of gas of each impurity component, in the order from low-pressure component to high-pressure component, use a quantitative tube which has valves at both ends to gradually add gas of each impurity component to the gas distribution bottle; use 2,3,3,3-tetrafluoropropene as the background gas, so as to narrow the content of each impurity with the to-be-test sample.

Balance it for 20 min ~ 30 min. The calibration standard sample is valid for 3d ~ 4d.

The mass mi of the gas of the impurity component i, which is expressed in grams (g), is calculated according to Formula (1):

Where:

Vi -- the volume of the gas of the added impurity component i, in milliliters (mL);

Mi -- the molar mass of the added impurity component i, in grams per mole (g/mol);

24 450 -- the value of the volume of 1 mol of gas at 25°C and 101.325 kPa (1 atm), in milliliters (mL).

Where: mi -- the mass of the impurity component i in the calibration standard sample, in grams (g); m -- the mass of the background sample in the calibration standard sample, in grams (g);

4.2.5.1.5 Determination of relative mass correction factor

Take a certain amount of calibration standard sample; measure according to fHFO-1234yf -- the correction factor of the peak area of 2,3,3,3-tetrafluoropropene;

Ai -- the peak area of the component i; fi -- relative mass correction factor of the component i.

The arithmetic mean of the results of two parallel determinations is taken as the report result. The absolute difference between the results of two parallel measurements shall not be greater than 0.10%.

4.3 Determination of moisture

It shall be performed according to the provisions of Karl Fischer Coulometry of 5.3, or Electrolysis of 5.4 in GB/T 7376-2008. Karl Fischer Coulometry shall be taken as the arbitration law.

4.4 Determination of acidity

It shall be performed according to provisions of GB/T 33065.

4.5 Determination of evaporation residue

It shall be performed according to provisions of GB/T 33066.

4.6 Determination of non-condensable gas in the gas phase

It shall be performed according to provisions of GB/T 33063. The external standard method shall be taken as the arbitration law. Typical chromatograms and relative retention values for the determination of non-condensable gases in the gas phase of 2,3,3,3-tetrafluoropropene for industrial use are given in Appendix B. The values of saturated vapor pressure at 25°C are given in Appendix C.

4.7 Determination of chloride (Cl-)

It shall be performed according to provisions of GB/T 33064.

5.1 Type inspection

All items which are specified in this Standard are type inspection items. Under normal production conditions, type inspections shall be conducted at least once a month. In any of the following cases, type inspection shall also be carried out:

a) when a key production process is updated;

b) when there are changes in the main raw materials;

c) date of manufacture or batch number;

d) product quality inspection results or inspection conclusions;

e) Code of this Standard.

6.3 Transportation

Since steel cylinders and tank cars which contain 2,3,3,3-tetrafluoropropene for industrial use are pressurized containers, during loading and unloading and transportation, they shall be lightly loaded and unloaded; the containers shall be fastened with helmets; and it is strictly prohibited to hit, drag, drop and direct sun exposure. The transportation shall comply with the relevant provisions of the People's Republic of China on the transportation of dangerous goods by railways and highways, and shall be accompanied by the "Chemical Safety Technical Data Sheet" and the "Chemical Safety Label".

6.4 Storage

2,3,3,3-tetrafluoropropene for industrial use shall be stored in a ventilated, cool and dry place; it cannot be placed near heat sources; and it is strictly prohibited to be exposed to sunlight, rain and corrosive substances.