Some standard content:
National Standard of the People's Republic of China
Chloropicrin
This standard applies to industrial chloropicrin made from picric acid by chlorination. Structural formula:
C1 - C NO2
Molecular formula: CCI, NO2
Molecular weight: 164.38 (according to the international atomic weight in 1979) 1 Technical conditions
1.1 Appearance: colorless or light yellow transparent liquid. 1.2 Industrial chloropicrin should meet the requirements of the following table: Index
First grade
Chloropicrin (CCI, NO2), content%
Density P2, g/ml
Free acid (in HNO2), %
Note: Density index is a spot check item.
2 Test method
2.1 Determination of chloropicrin content
2.1.1 Reagents and solutions
Anhydrous ethanol (GB678-78): analytical grade. 99.0
1.654~1.663
Nitric acid (GB62678): analytical grade, 6N solution. Standard
UDC661.52
GB435-84
Replace GB435-64
Secondary product
1.652~1.663
Silver nitrate (GB670-77): analytical grade, 0.1N standard solution, prepared and calibrated according to GB601-77 "Preparation method of standard solution of chemical reagents".
B3-1078—77): Analytically pure, 5% solution. Anhydrous sodium sulfite (HB
Ammonium ferric sulfate (GB1279-77): analytical grade, 40% solution. Sodium chloride (GB1266-77): superior grade. Potassium thiocyanate (GB648-78): analytical grade, 0.1N standard solution. 2.1.1.7
2.1.1.7.1
Preparation: Weigh 10 grams of potassium thiocyanate, dissolve it in distilled water, transfer it into a 1000 ml volumetric flask, and dilute it with distilled water to the scale.
GB435-84
2.1.1.7.2 Calibration: Weigh about 1.5 grams of sodium chloride (dried to constant weight at 500-600℃) Grams (accurate to 0.0002 grams), dissolved in a 250 ml volumetric flask, diluted to the mark, and spread evenly. Pipette 25 ml of the solution into a 250 ml conical flask, add 25 ml of anhydrous ethanol and 5 ml of 6N nitric acid solution. Then accurately add 50 ml of 0.1N silver nitrate standard solution, shake well, then add 3 ml of 40% ammonium ferric sulfate solution, and titrate with potassium thiocyanate standard solution until the solution turns light red. The end point is if it does not disappear within 30 seconds. Under the same conditions, perform a blank test. The titration rate of potassium thiocyanate standard solution should be controlled at 3.5~4.5 ml per minute. 2.1.1.7.3 Calculation: The equivalent concentration of potassium thiofluoride standard solution is calculated according to formula (1): 25G
Where: G
The weight of sodium chloride, grams,
( V, -V)×0.05846
The volume of potassium thiocyanate standard solution consumed when titrating sodium chloride, milliliters: V, the volume of potassium thiocyanate standard solution consumed during the blank test, liters; 0.05846
The number of grams per milligram equivalent of sodium chloride.
2.1.2 Determination procedure
Use a small ampoule ball to weigh 0.15-0.20 grams of sample (accurate to 0.0002 grams), place it in a 250-ml ground-mouth conical flask with a reflux condenser, add 25 ml of anhydrous ethanol and 25 ml of 5% sodium sulfite solution, and carefully break the small ampoule ball with a glass rod. Connect the conical flask to the condenser and heat it in a water bath. Bring the sample to a boil within 30-40 minutes and keep it for 1.5 hours, then stop heating. Add 25 ml of 6N nitric acid, shake from time to time to expel the gas in the bottle. Cool to room temperature, accurately add 50 ml of 0.1N silver nitrate standard solution and 3 ml of 40% ammonium ferric sulfate solution, then back-titrate with 0.1N potassium thiocyanate standard solution until light red, if it does not disappear within 30 seconds, it is the end point. Perform a blank test at the same time.
2.1.3 Calculation of results
The content of chloropicrin (X,) is expressed as weight percentage and calculated according to formula (2): (V,-V)×N×0.05479
Where:.
The amount of potassium thiocyanate standard solution consumed by the sample, ml: The amount of potassium thiocyanate standard solution consumed by the blank, ml; The equivalent concentration of the standard solution;
The weight of the sample, g;
The milligram equivalent of chloropicrin, g.
The error of the half-line analysis is not more than 0.3%.
2.2 Determination of free acid content
2.2.1 Reagents and solutions
2.2.1.1 Sodium hydroxide (GB629-77): 0.1N standard solution, prepared and calibrated according to GB601-77. 2.2.1.2 Methyl red (HG3-958-76): 0.1% ethanol solution. 2.2.2 Determination procedure
Pick up 50 ml of chloropicrin sample and place it in a separatory funnel containing 100 ml of distilled water. Shake for 5 minutes, separate the water layer, add 100 ml of distilled water to the separatory funnel, shake it thoroughly, separate the water layer again, combine the two extracts, and titrate to the end point with 0.1N sodium hydroxide standard solution using methyl red as the indicator. 2.2.3 Calculation of results
The free acid (HNO) content (X) is expressed as a percentage by weight and is calculated according to formula (3): X,=V×N×0.063
Pzm×50
Wherein:
Sample consumes sodium hydroxide standard solution, ml; x100*
GB435-84
N——equivalent concentration of sodium hydroxide standard solution; P2—
density of chloropicrin, g/ml:
milligram equivalent of mononitric acid, g.
Parallel analysis error is not greater than 0.001%.
2.3 Determination of density (P2o)
2.3.1 Instrument
2.3.1.1 Constant temperature water bath: 20±℃. wwW.bzxz.Net
2 Glass density meter: 1.600~1.700 g/ml or 1.650~1.700 g/ml, graduation value 0.001 g/ml. 2.3.1.2
2.3.1.3 Measuring cylinder: 100 ml measuring cylinder with stopper, with a thermometer of 0~50℃ (graduation value 0.1℃) on the stopper. 2.3.2 Determination procedure
Inject about 80 ml of sample into the measuring cylinder, cover it, and place it in a constant temperature water bath to maintain a constant temperature of 20±0.1℃. When the temperature inside and outside the measuring cylinder reaches equilibrium, the density meter can be used for determination, and the density value can be accurately read from the lower edge of the meniscus of the density meter. The error of parallel determination shall not exceed 0.005 g/ml. 3 Inspection rules
According to the provisions of GB1604-79 "Pesticide Acceptance Rules" and GB1605-79 "Commercial Pesticide Sampling Methods". 4 Packaging, marking, storage and transportation
4.1 Chloropicrin is packaged in galvanized iron barrels, with a net weight of 25 kg or 50 kg per barrel. 4.2 The packaging should indicate: the name of the manufacturer, product name, batch number, production date, net weight and the number of this standard. The packaging should be accompanied by the "highly toxic" mark specified in GB190-73 "Dangerous Goods Packaging Marking". 4.3 Packaging
4.4 Each batch of packaged finished products should be accompanied by a quality certificate, which includes: the name of the manufacturer, product name, batch number, production date, net weight, and proof that the product quality meets this standard. 4.5 During transportation, it must not be collided or placed upside down, and must be strictly protected from moisture and sunlight, and maintained in good ventilation. It must not be mixed with food, seeds, and feed, and must avoid contact with the skin and prevent inhalation through the mouth and nose. Additional remarks:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China, and is technically managed by the Shenyang Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by Dalian Dyestuff Factory. The main drafters of this standard are Sun Fuling and Hu Huansong. This standard was first issued in October 1964.
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