Some standard content:
National Standard of the People's Republic of China
Ethylene glycol for industrial use-Specification
1 Subject content and scope of application
GB4649—93||tt| |Replaces GB4649--84
This standard specifies the technical conditions, test methods, inspection rules, marking, packaging, transportation, storage, etc. of industrial ethylene glycol. This standard applies to ethylene glycol produced by direct oxidation of ethylene to obtain ethylene oxide and then hydration. This product is mainly used as a monomer for the production of polyester, alkyd resin and electrolyte for electrolytic capacitors. In addition, it can also be used as antifreeze, plasticizer, solvent, etc.
Molecular formula: C2H.O2
H
H
Structural formula:
H
OHOH
Relative molecular mass: 62.069 (according to the 1987 international relative atomic mass) 2 cited standards
GB601
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB/T3049
GB/T3143|| tt || GB/T4472 | Unit - platinum to diamond color number) General rules for determination of density and relative density of chemical products Determination of moisture content in chemical products Karl Fischer method (general method) General rules for sampling of liquid chemical products
Analytical laboratory water specifications and tests Method GB66822
Determination of ash content of organic chemical products
GB/T7531
GB/T7534
GB10479
Determination of boiling range of industrial volatile organic liquids Technical conditions for aluminum railway tank cars
GB/T14571.1-93 Determination of acidity of industrial ethylene glycol Titration method GB/T14571.2-93 Content of diethylene glycol and triethylene glycol in industrial ethylene glycol Determination of aldehyde content in GB/T14571.3-93 Determination of aldehyde content in industrial ethylene glycol Spectrophotometric method SH/T1053 Determination of boiling range of industrial diethylene glycol 3 Technical requirements
Gas chromatography
Industrial ethylene glycol should comply with the physical and chemical indicators specified in Table 1 and be tested according to the test methods specified in this standard. Approved by the State Bureau of Technical Supervision on 1993-07-21 for implementation on 1994-07-01
Indicator name
Exterior
Chroma (platinum-diamond)
Before heating, no.
After heating with hydrochloric acid, No.
Density (20℃), g/cm
View
Boiling range (at 0℃, 0.10133MPa) ||tt| |Initial boiling point, ℃
Dry point, ℃
Moisture content, %
Acidity (calculated as acetic acid), %
Iron content (calculated as Fe), %
Ash content, %
Diethylene glycol and triethylene glycol, %≤
Aldehyde content (calculated as formaldehyde), %
UV transmittance, %| |tt||220nm
275nm
350nm
>
GB4649—93
Table 1
refers to
excellent Grade
Colorless and transparent
No mechanical impurities
5
20
1.1128~1.1138
196
199
0.1
0.002
0.00001
0.001
0.1
0.001
70
90|| tt||98
Note: UV transmittance is only measured for high-quality products for export. 4 Test methods
4.1 Appearance measurement
First class product
Colorless and transparent
No mechanical impurities
15
Standard||tt ||1.1125~1.1140
195
200
0.2
0.005
0.0005
0.002
1.0||tt ||Qualified product
Colorless or slightly yellow
No mechanical impurities
40
1.112 0~1.115 0
193
204
0.01
Take 50~60mL ethylene glycol sample, place it in a clean and dry 100mL colorimetric tube, and conduct direct visual inspection under sunlight or fluorescent lamp transmission.
If there is any dispute, take 100g of the sample and use a No. 4 glass filter pot with constant weight to suction filter. The suction filtration speed should be controlled to make the filtrate appear in drops, and then wash it with distilled water 4 to 5 times. The dosage is about 20mL. Then, move it into the oven and bake it at 105-110°C until it reaches constant weight. When the increment is no more than 1 mg, it is considered to be free of mechanical impurities.
4.2 Colorimetry
4.2.1 Colorimetry before heating
Conduct according to the provisions of GB/T3143, using a 100mL colorimetric tube. 4.2.2 Colorimetry after adding hydrochloric acid and heating
4.2.2.1 Instruments, blood vessels and reagents
Adjustable electric furnace.
a
b.
c.
d.
e.
Pipette: 1mL.
GB4649-93
Standard ground-mouth conical flask: 250mL.
Glass capillary tube: about 1mm in diameter and 10mm in length. Boil it with hydrochloric acid, then wash it with distilled water and dry it. Standard ground air cooling tube, see picture.
415
Standard ground air cooling tube diagram
Hydrochloric acid: superior grade pure. | |tt | Connect the Erlenmeyer flask to the air cooling tube. Preheat the electric furnace for 5 minutes, then place the Erlenmeyer flask with the air cooling tube on the electric furnace, adjust the voltage so that the test solution reaches boiling in 5 minutes, and boil for 30 seconds. Remove the Erlenmeyer flask (still with air cooling tube) and cool for 1 hour. Colorimetric measurement is the same as 4.2.1.
4.2.3 Repeatability
The lower limit of determination of this method is 5 chromaticity numbers, and the difference between repeated measurement results should not be greater than 2 chromaticity numbers. 4.3 Density measurement
shall be carried out according to the provisions of 2.3.1 in GB/T4472, using a 50cm pycnometer. The density can be measured at room temperature within the range of 15°C to 40°C, and corrected to the sample density P2o (g/cm\) at 20°C according to formula (1). p,
(mg-m)+A
PH,o
(mg-m)+A
A=0.0012(ma-m)||tt ||P20=p,+0.00070(t-20)
Where: m
m2
Pycnometer mass, g;
Pycnometer plus sample mass , g;
m3—the mass of water added to the pycnometer, g
(1)
·2)
(3)
A-|| tt||0.0012-
p
PH,o
0.00070
Buoyancy correction value;
Air density at 20℃, g/cm;| |tt||GB4649-93
The density value of the sample measured when the room temperature is t, g/cm; the density of water at the temperature t (see Table 2), g/cm2; the temperature when the density of the sample is measured , ℃:
For every increase or decrease of 1℃ in the range of 15℃ to 40℃, ethanol =. The alcohol density correction value analysis result is the arithmetic mean of the two repeated measurement results. Repeatability is: the difference between two repeated measurement results should not be greater than 0.0002g/cm2 (95% confidence level). Table 2 Density values ??of water at different temperatures
Temperature, ℃
15
16
17
18
19||tt| |20
21
22
23
24
25
26
27
4.4 Boiling range determination
Density+g/cm*bZxz.net
0.9991
0.9990
0.9988
0.9986
0.998 4
0.9982
0.998 0
0.997 8
0.997 6||tt ||0.9973
0.9971
0.9968
0.9965
Temperature, c
28
29
30||tt ||31
32
33
34
35
36
37
38
39
40
Density, g/ema
0.996 3
0.9960
0.9957
0.9954
0.9951|| tt||0.9947
0.9944
0.9941
0.9937
0.9934
0.9930
0.9926
0.9922||tt| |According to the provisions of GB/T7534. The heat source is a 500W electric furnace or gas lamp. The main thermometer is a rod-shaped glass thermometer marked with a scale value of 150-220C and a graduation value of 0.1C. The distance between the top of the temperature-sensitive bulb and the first scale line is at least 100mm. Repeatability is: the difference between two repeated measurement results, the initial boiling point should not be greater than 0.5°C, and the dry point should not be greater than 0.4°C (95% confidence level).
It is also allowed to use the device specified in SH/T1053 for measurement. 4.5 Moisture determination
shall be carried out in accordance with the provisions of GB/T6283.
The analysis result is the arithmetic mean of the two repeated measurement results. Repeatability is: when the moisture content is in the range of 0.02% to 0.1%, the difference between the two repeated measurement results should not be greater than 15% of the average value; when the moisture content is greater than 0.1%, the difference between the two repeated measurement results should not be greater than 10% of its mean (95% confidence level). 4.6 Determination of acidity
shall be measured according to the provisions of GB/T14571.1. 4.7 Determination of iron content
GB4649-93
shall be carried out in accordance with the provisions of GB/T3049. However, when drawing the standard curve and measuring samples, a 100mL volumetric flask or a 100mL colorimetric tube must be used, and a 3cm (or 5cm) cuvette must be used. The sampling volume is about 80g. The analysis result is the arithmetic mean of the two repeated measurement results. Repeatability is: when the iron content is ≤0.00005%, the difference between the two repeated measurement results should not be greater than 15% of the average value; when the iron content is >0.00005%, the difference between the two repeated measurement results should not be greater than its average value. 10% of the mean (95% confidence level). 4.8 The determination of ash content
shall be carried out in accordance with the provisions of GB/T7531. A 100mL porcelain crucible is used, the sampling volume is about 80g, and the burning temperature is 800°C. The analysis result is the arithmetic mean of the two repeated measurement results. Repeatability is: the difference between two repeated measurement results should not be greater than 0.0005% (95% confidence level).
4.9 The content of diethylene glycol and triethylene glycol shall be measured according to the provisions of GB/T14571.2. 4.10 Determination of aldehyde content
shall be determined according to the provisions of GB/T14571.3. 4.11 Ultraviolet transmittance measurement
4.11.1 Instruments and reagents
4.11.1.1 Ultraviolet spectrophotometer: Use hydrogen lamp or atmosphere lamp as light source to measure transmittance in the wavelength range of 190~350nm The error should not exceed 1%.
Note: The accuracy of the instrument's wavelength and transmittance is the key to ensuring effective measurement, especially at 220nm, because the slope of the transmittance curve here is large. 4.11.1.2 Quartz cuvette: light diameter 1cm. 4.11.1.3 Distilled water: complies with the Grade-A water requirements specified in GB6682-86. 4.11.2 Measurement steps
4.11.2.1 Carefully clean the cuvette used (acetone cannot be used), and verify the identity of the cuvette according to the operating procedures specified by the instrument. 4.11.2.2 Inject distilled water into the reference cell and the ethylene glycol sample to be tested into the sample cell. Measure the light transmittance under three wavelength conditions: 220nm, 275nm, and 350nm. When necessary, the measured transmittance needs to be corrected for cuvette differences and instrument baseline drift. 5 Inspection Rules
5.1 Ethylene glycol should be inspected by the technical inspection department of the manufacturer. The manufacturer should ensure that all products shipped meet the requirements of this standard and should be accompanied by a quality certificate in a certain format. 5.2 Sampling of ethylene glycol products shall be carried out in accordance with GB/T6680 General Sampling Rules for Liquid Chemical Products. For tank car sampling, in addition to taking samples from the first and last cars of the entire tank car train, one sample will be taken from every four other cars. If the entire train contains less than 7 vehicles, the number of samples should be no less than 3 vehicles. 5.3 Density, iron content, and ash content should be measured regularly, no less than once a month. 5.4 When the user requires the determination of chloride content, see Appendix A for the test method. The fluoride content (calculated as Cl) should not be greater than 0.5ppm. 5.5 Users can check whether the quality of ethylene glycol meets the requirements of this standard within 7 days of receipt according to the inspection rules and test methods specified in this standard.
5.6 If the inspection results do not meet the requirements of this standard, double sampling should be carried out for re-examination. If even one indicator does not meet the requirements of this standard as a result of the re-inspection, the batch of ethylene glycol will not be accepted.
6 Marking, packaging, transportation, storage
6.1 Ethylene glycol should be loaded into railway tank cars in aluminum or stainless steel containers (in compliance with the technical conditions of GB10479 aluminum railway tank cars) or in ship cabins. The car or cabin should be marked "Ethylene Glycol Only". 6.2 Before loading ethylene glycol into a railway tank car or ship hold with residual liquid, the residual liquid must be inspected in accordance with the requirements of this standard. If the residual liquid meets this standard, ethylene glycol products can be loaded into the tank truck or ship cabin; if it does not meet this standard, the residual liquid should be drained and the tank truck or ship cabin should be cleaned. GB 4649-93
Then use steam treatment and dry it before loading ethylene glycol products. 6.3 Each batch of manufactured products should be accompanied by a quality certificate: the content includes: product name, manufacturer name, product grade, batch number, trademark, inspection date.
period, quality indicators that meet the requirements of this standard and this standard number . 6.4 Ethylene glycol is a water-absorbent substance, and the packaging container should be kept airtight during storage and transportation. 7 Safety requirements | 5mg/m. The sampling site requires good ventilation, and glycol on the ground or equipment should be flushed with plenty of water. 7.2 Fire-fighting equipment: Production equipment should be equipped with various fire-fighting equipment in accordance with relevant regulations. Fine atomized water, foam or inert gas should be used to extinguish fire. Principle of method A1
GB4649-93
Appendix A
Determination of chloride content
(Supplement)
Chloride ions and silver nitrate in the sample Reaction produces white silver chloride precipitate, which is then compared with the standard solution for turbidity. A2 instruments and reagents
A2.1
constant temperature water bath.
Ground mouth colorimetric tube: 25mL.
A2.2
A2.3 Sodium chloride: benchmark reagent.
A2.4 nitrogen water.
A2.5 nitric acid.
A2.6 silver nitrate: 5% (m/m) aqueous solution; prepared and stored in accordance with GB601-88. A2.7 Chlorine standard solution:
A2.7.1 Chlorine standard solution A: Weigh 0.1649g of sodium chloride (A2.3) that is burned to constant weight at 500~600C, dissolve it in water, and transfer it to 1000mL capacity bottle, dilute to volume and shake. This solution contains 0.1 mg of chlorine per milliliter. A2.7.2 Chlorine standard solution B: Use a pipette to absorb 5 mL of chlorine standard solution A. Place it in a 100 mL volumetric flask, add water to dilute to the mark, and shake well. This solution contains 0.005 mg of chlorine per milliliter. A3 Measurement steps
A3.1 Take 2 ground colorimetric tubes (A2.2), add 4.5mL of ethylene glycol sample to one of them, and add 0.5mL of chlorine standard solution B to the other.
A3.2 Add 1.5mL of ammonia water (A2.4) to the above colorimetric tubes, shake well, heat in a constant temperature water bath at 70~80℃ for 15min, cool and add 3mL of nitric acid (A2.5), Silver nitrate solution (A2.6) 1mL, dilute to the mark with water, shake well and let stand for 2 minutes. Observe on the black bottom plate. The turbidity of the sample should not be greater than the turbidity of the chlorine-containing standard solution. Additional notes:
This standard is proposed by China Petrochemical Corporation. This standard is under the jurisdiction of the National Petrochemical Standardization Technical Committee. This standard is drafted by the First Chemical Plant of Beijing Yanshan Petrochemical Company. The main drafters of this standard are Li Zhenjie, Wang Niansong, Huang Yiyuan, Xue Lin and Lu Lanjing. This standard refers to the former Soviet Union national standard "OCT1971083 "Technical Conditions for Ethylene Glycol".
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