Some standard content:
Chemical Industry Standard of the People's Republic of China
HG2031—91
Industrial Nitromethane
Published on 1991-06-26
Ministry of Chemical Industry of the People's Republic of China
Implemented on 1992-01-01
Chemical Industry Standard of the People's Republic of China
! Nitromethane
Subject Content and Scope of Application
HG2031—91
This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, transportation, storage, etc. of industrial nitromethane. This standard applies to industrial nitromethane made from natural gas and nitric acid. This product is mainly used as a raw material for synthetic dyes, fuels, explosives, pesticides, and medicines.
Molecular formula CHsNO2
Relative molecular mass 60.04 (according to the international relative atomic mass in 1987)2
Cited standards
GB1250
GB2366
GB3143
GB4472
GB6678
GB6680
GB9722
3Technical requirements
Dangerous goods packaging mark||t t||Preparation of standard solutions for titration analysis (volumetric analysis) of chemical reagents Preparation of standard solutions for determination of impurities of chemical reagents Methods for expressing and judging limit values Determination of water content in chemical products Gas chromatography Color determination of liquid chemical products (Hazen unit - platinum - diamond color number) General rules for determination of density and relative density of chemical products General rules for sampling of chemical products
General rules for sampling of liquid chemical products
General rules for gas chromatography of chemical reagents
3.1 Appearance is transparent liquid.
3.2 Industrial nitromethane shall meet the following requirements:
Color (platinum-cobalt), No.
Density (pa0), g/cm2
Water content, %
Acidity (measured in acetic acid), %
Nitromethane, %
Total nitroalkanes, %
Test method
Superior quality
1.130—1.136
First quality
1.130—1.136
The reagents and water used in this standard, unless otherwise specified, shall be analytically pure reagents that meet the current national standards or industry standards. Approved by the Ministry of Chemical Industry of the People's Republic of China on June 26, 1991 and implemented on January 1, 1992
and distilled water or water of corresponding purity.
HG 203191
The standard solution for titration analysis and the standard solution for impurities are prepared according to GB601 and GB602 respectively. 4.1 Determination of chromaticity
The determination is carried out according to the method specified in GB3143.
4.2 Determination of density
The determination is carried out according to the provisions of Article 2.3.3 of GB4472. 4.2.1 Density meter: graduation value 0.0005g/cm. 4.2.2 Density temperature correction coefficient of nitromethane is 0.0012g/cm℃. 4.2.3 Allowable difference
The difference between the results of two parallel determinations is not greater than 0.0005g/cm, and the arithmetic mean is taken as the test result. 4.3 Determination of moisture
The determination is carried out according to the method specified in GB2366.
The reference conditions for chromatographic operation and the chromatogram are shown in Appendix A. 4.4 Determination of acidity
4.4.1 Principle
Dissolve the sample in an ethanol-acetone mixed solvent and titrate with a potassium hydroxide standard solution. Take the number 9.5-10 indicated on the pH meter as the end point and calculate its acidity.
4.4.2 Reagents and solutions
a. Potassium hydroxide-ethanol standard titration solution: c(KOH)=0.1mol/L; b. Ethanol-acetone solution: 1+1(V+V); Sodium tetraborate standard buffer solution (pH9.18 at 25℃), which is prepared as follows: c.
Weigh 0.95g of sodium tetraborate, dissolve it in carbon dioxide-free distilled water, and dilute it to 250mL in a volumetric flask. 4.4.3 Instruments
25-type acidometer or other equivalent acidometers: a.Www.bzxZ.net
Magnetic stirrer;
c. Pipette: 25mL;
Beaker, 200mL.
4.4.4 Analysis Steps
According to the instructions for using the acidometer, preheat the acidometer to stabilize it, and calibrate the instrument to pH 9.18 with H-9.18 sodium tetraborate standard buffer (4.4.2.C), then add 75mL of ethanol-acetone mixed solvent to a 200mL beaker, and then use a pipette to draw 25mL of sample into a 200mL beaker, and place the beaker on a magnetic stirrer to stir evenly, insert the electrode, and titrate with potassium hydroxide-ethanol standard titration solution until the acidometer reading is 9.5-10 (stable for 30s), which is the end point. 4.4.5 Calculation of results
Acidity r (in acetic acid) is calculated according to formula (1): C.VX0.06,
Wherein: c--actual concentration of potassium hydroxide-ethanol standard titration solution, mol/L; -
-volume of potassium hydroxide-ethanol standard titration solution consumed in titration, mL; 25--volume of sample, mL,
-density of sample, /cm
0.06--mass of acetic acid in grams equivalent to 1.00mL potassium hydroxide-ethanol standard titration solution Cc(KOH)=1.000mol/LJ.
4.4.6 Allowable difference
HG2031-91
The difference between the results of two parallel determinations shall not exceed 0.01%, and the arithmetic mean shall be taken as the determination result. 4.5 Determination of nitromethane and total nitroalkanes (gas chromatography) The general requirements of this test method shall be carried out in accordance with the provisions of GB9722. 4.5.1 Principle of the method
Nitromethane sample, under the selected appropriate chromatograph working conditions, the impurity peaks of nitromethane are separated, and the contents of nitromethane and total nitroalkanes are calculated according to the internal standard method using known correction factors. 4.5.2 Reagents and materials
Celite545 or other equivalent white diatomaceous earth carrier: particle size 0.18-0.25mm (80-60 mesh); a.
Tricresol phosphate: chromatographic stationary liquid;
Silicone oil DC703: chromatographic stationary liquid;
Isoamyl alcohol (ZBG63001);
Ether;
Hydrogen: purity greater than 99.9%.
Instruments and equipment
Gas chromatograph: equipped with thermal conductivity detector, S500mV·ml/mg (benzene); b.
Recorder or integrator, digital processor; injector: 10μl;
Chromatographic column: Column A is 1m long and 4mm in inner diameter stainless steel column, and its filling material is diatomaceous earth carrier 1 silicone oil Dc703 = 100:30 (m/m);
Column B is 2m long and 4mm in inner diameter stainless steel column, and its filling material is diatomaceous earth carrier : tricresyl phosphate = 100:30 (m/m).
Column A and column B are used in series.
4.5.4 Preparation
a. Preparation of chromatographic column: Weigh 3g of silicone oil and 6g of tricresyl phosphate respectively, place them in two beakers, dissolve them with ether, then add 10g and 20g of diatomaceous earth respectively, stir with a spoon, place under an infrared lamp, and dry under frequent stirring for later use. b. Filling and loading amount of chromatographic column: Block one end of the chromatographic column tube with a little glass wool or copper mesh, and connect this end to the exhaust system. Under gentle vibration, load the prepared stationary phase into the chromatographic column from the other end through a funnel. The loading amount is about 3g for column A and about 6g for column B; c. Aging of chromatographic column: Heat to 115℃ with carrier gas, and age for 16h. 4.5.5 Reference conditions for chromatographic test, determination of correction factors and chromatograms are shown in Appendix B. 4.5.6 Analysis steps
Select a clean and airtight sample bottle and weigh it (accurate to 0.0002g), then add about 2g of sample (accurate to 0.0002g), then add about 0.07g of isoamyl alcohol to the sample bottle (the amount should be close to the content of nitroethane, the main impurity in the sample), weigh it (accurate to 0.0002g), shake it well, and use it as the sample. Use a 10μl syringe to take 5μl of the sample from the prepared sample and inject it into the chromatograph. After all the peaks of each component have appeared, calculate the content of each component according to the area of each chromatographic peak. 4.5.7 Calculation of results
The mass percentage of 1-nitropropane, 2-nitropropane, ethyl acetate, acetone, methanol, water, acetaldehyde and formaldehyde in the sample is expressed as X, and is calculated according to formula (2).
The mass percentage of nitromethane X1 is calculated according to formula (3). A,·m
IsTX100
HG2031—91
X,=100-2X-X
The mass percentage of total nitroalkanes is calculated according to formula (4) X2-Xi+Xa+X,+X6
wherein, Ar——peak area of the component to be measured, mm2; A,—peak area of isopentanol (internal standard), mm\; f. .——correction factor of component i compared with the internal standard substance; mass of isopentanol, nom;
m—mass of sample, g,
ZX——total amount of chromatographic impurities, %;
X——acid content, %;
X3——nitroethane content, %:
X.——2-nitropropane content, %,
-1-nitropropane content, %;
4.5.8 The allowable difference (nitromethane and total nitroalkanes) of two parallel determination results shall not exceed 0.3%, and the arithmetic mean value shall be taken as the test result. Note: (3) The formula already includes the moisture content. 5 Inspection rules
(4)
5. Nitromethane is inspected by the factory inspection department. The factory should ensure that all products leaving the factory meet the requirements of this standard. Each batch of products leaving the factory should be accompanied by a product quality certificate. 5.2 The user has the right to verify the quality of the industrial nitromethane received in accordance with the inspection rules and inspection methods specified in this standard to verify whether its indicators meet the requirements of this standard. 5.3 Sampling method: Samples should be taken from the top, middle and bottom of the tank. When barreled, the number of sampling barrels should be sampled according to the 3×N specified in GB6678 (when N≤10, the sampling is for all units; when 11≤N≤49, the sampling shall not be less than 11), and the total amount of samples taken shall not be less than 1L. 5.4 After shaking the sample, divide it into two clean, dry glass bottles with ground stoppers in equal amounts, attach labels and indicate: product name, batch number, sampling date, and sampler. One bottle is used for analysis and inspection, and the other bottle is kept for 8 months for inspection. 5.5 In the test results, if any index does not meet the requirements of this standard, re-sample from twice the amount of packaging containers for re-inspection. If even one index does not meet the requirements, the entire batch of products is unqualified. 5.6 The technical index values are determined by the rounded value comparison method in GB1250. 6 Packaging, marking, storage and transportation
6.1 Packaging
Nitromethane should be packaged in dry, clean, and sealed composite packaging barrels (6HA1), or other containers that can ensure product quality and transportation requirements (net weight of each barrel is 200kg).
6.2 Marking
The packaging barrel should be painted with firm markings, including: manufacturer name, product name, batch number, net weight, gross weight and signs of flammable and explosive items specified in GB190.
6.3 Storage
Nitromethane should be placed in a cool, ventilated and dry place, away from sunlight, heat sources and fire sources. The product has a shelf life of 8 months from the date of packaging.
6.4 Transportation
Nitromethane should not be hit, rubbed or dragged during transportation, and the integrity of the packaging should be ensured. 4
Safety requirements
HG203191
7.1 Nitromethane is acidic, toxic, flammable and explosive. When operating, labor protection equipment should be worn and there should be an emergency water source on site. 7.2 Strictly abide by the national safety regulations on fire protection and dangerous goods. When a fire occurs, foam, carbon dioxide and water can be used to extinguish the fire. 7.3 Nitromethane should be kept away from alkali, rubber, iron, etc. 5
A1 The reference conditions for chromatographic operation are as follows
Column temperature, ℃
Detection chamber temperature, ℃
Vaporization chamber temperature, ℃
Carrier gas (H2) flow rate, m1/min
Identifier
Injection volume 1
The actual sample chromatographic peak is shown in Figure A2
The reference conditions for chromatographic operation are as follows
Column temperature, ℃
Vaporization chamber temperature, ℃
Bridge current, mA
Carrier gas (H2) flow rate, ml/min
Injection volume 1
Determination of correction factor
HG2031—91
Appendix A
Determination of water content in nitromethane
(reference)
Figure ACDX102 chromatographic column
1—air peak; 2—water peak; 3—nitromethane peak; nitromethane peak Appendix B
Determination of nitromethane and total nitroalkanes content (reference)
HG 203191
Use a clean, dry, sealable ground-mouth bottle, by the weight addition method, and use nitromethane as a diluent to prepare a series of mixed samples of nitroethane, 1-nitropropane, 2-nitropropane, water, acetonitrile, methanol, formaldehyde, acetaldehyde and isopentanol that are close to those in the sample, and carry out determination according to the sample determination operating conditions.
The correction factor value must be calibrated regularly, usually every three months. If a significant change is found, it must be re-measured. B2.1 Correction factor calculation formula:
Wherein: fs.t——Correction factor of component i compared with the mass of the internal standard. A Peak area of internal standard isopentanol, mm\;
A Peak area of component i, mm
m——Mass percentage of component i, %;
m——Mass percentage of isopentanol, %.
B3 Typical chromatogram of nitromethane
Typical spectra of impurities of nitromethane on tricresyl phosphate/diatomite 545 and silicone oil DC703/diatomite 545 chromatographic columns
1—air peak; 2—formaldehyde; 3—acetaldehyde; 4—methanol; 5—water; 6—acetone; 7—unknown peak; 8—ethyl; 9—unknown peak; 10—nitromethane; 11—nitroethane; 12—2-nitropropane; 13—isoamyl alcohol; 14—1-nitropropane. 7
Additional remarks:
HG2031—91
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the technical jurisdiction of the Beijing Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Sichuan State-owned Luzhou Chemical Plant. The main drafters of this standard are Zou Xinchun and Liu Guangwu.4 Transportation
Nitromethane should not be bumped, rubbed or dragged during transportation, and the integrity of the packaging should be ensured. 4
Safety requirements
HG203191
7.1 Nitromethane is acidic, toxic, flammable and explosive. When operating, labor protection equipment should be worn and there should be an emergency water source on site. 7.2 Strictly abide by the national safety regulations on fire protection and dangerous goods. When a fire occurs, foam, carbon dioxide and water can be used to extinguish the fire. 7.3 Nitromethane should avoid contact with alkali, rubber, iron, etc. 5
A1The reference conditions for chromatographic operation are as follows
Column temperature, ℃
Detection chamber temperature, ℃
Vaporization chamber temperature, ℃
Carrier gas (H2) flow rate, m1/min
Identifier
Injection volume 1
The actual sample chromatographic peak is shown in Figure A2
The reference conditions for chromatographic operation are as follows
Column temperature, ℃
Vaporization chamber temperature, ℃
Bridge current, mA
Carrier gas (H2) flow rate, ml/min
Injection volume 1
Determination of correction factor
HG2031—91
Appendix A
Determination of water content in nitromethane
(reference)
Figure ACDX102 chromatographic column
1—air peak; 2—water peak; 3—nitromethane peak; nitromethane peak Appendix B
Determination of nitromethane and total nitroalkanes content (reference)
HG 203191
Use a clean, dry, sealable ground-mouth bottle, by the weight addition method, and use nitromethane as a diluent to prepare a series of mixed samples of nitroethane, 1-nitropropane, 2-nitropropane, water, acetonitrile, methanol, formaldehyde, acetaldehyde and isopentanol that are close to those in the sample, and carry out determination according to the sample determination operating conditions.
The correction factor value must be calibrated regularly, usually every three months. If a significant change is found, it must be re-measured. B2.1 Correction factor calculation formula:
Wherein: fs.t——Correction factor of component i compared with the mass of the internal standard. A Peak area of internal standard isopentanol, mm\;
A Peak area of component i, mm
m——Mass percentage of component i, %;
m——Mass percentage of isopentanol, %.
B3 Typical chromatogram of nitromethane
Typical spectra of impurities of nitromethane on tricresyl phosphate/diatomite 545 and silicone oil DC703/diatomite 545 chromatographic columns
1—air peak; 2—formaldehyde; 3—acetaldehyde; 4—methanol; 5—water; 6—acetone; 7—unknown peak; 8—ethyl; 9—unknown peak; 10—nitromethane; 11—nitroethane; 12—2-nitropropane; 13—isoamyl alcohol; 14—1-nitropropane. 7
Additional remarks:
HG2031—91
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the technical jurisdiction of the Beijing Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Sichuan State-owned Luzhou Chemical Plant. The main drafters of this standard are Zou Xinchun and Liu Guangwu.4 Transportation
Nitromethane should not be bumped, rubbed or dragged during transportation, and the integrity of the packaging should be ensured. 4
Safety requirements
HG203191
7.1 Nitromethane is acidic, toxic, flammable and explosive. When operating, labor protection equipment should be worn and there should be an emergency water source on site. 7.2 Strictly abide by the national safety regulations on fire protection and dangerous goods. When a fire occurs, foam, carbon dioxide and water can be used to extinguish the fire. 7.3 Nitromethane should avoid contact with alkali, rubber, iron, etc. 5
A1The reference conditions for chromatographic operation are as follows
Column temperature, ℃
Detection chamber temperature, ℃
Vaporization chamber temperature, ℃
Carrier gas (H2) flow rate, m1/min
Identifier
Injection volume 1
The actual sample chromatographic peak is shown in Figure A2
The reference conditions for chromatographic operation are as follows
Column temperature, ℃
Vaporization chamber temperature, ℃
Bridge current, mA
Carrier gas (H2) flow rate, ml/min
Injection volume 1
Determination of correction factor
HG2031—91
Appendix A
Determination of water content in nitromethane
(reference)
Figure ACDX102 chromatographic column
1—air peak; 2—water peak; 3—nitromethane peak; nitromethane peak Appendix B
Determination of nitromethane and total nitroalkanes content (reference)
HG 203191
Use a clean, dry, sealable ground-mouth bottle, by the weight addition method, with nitromethane as the diluent, to prepare a series of mixed samples of nitroethane, 1-nitropropane, 2-nitropropane, water, acetonitrile, methanol, formaldehyde, acetaldehyde and isopentanol that are close to those in the sample, and carry out the determination according to the sample determination operating conditions.
The correction factor value must be calibrated regularly, usually every three months. If a significant change is found, it must be re-measured. B2.1 Correction factor calculation formula:
Wherein: fs.t——Correction factor of component i compared with the mass of the internal standard. A Peak area of internal standard isopentanol, mm\;
A Peak area of component i, mm
m——Mass percentage of component i, %;
m——Mass percentage of isopentanol, %.
B3 Typical chromatogram of nitromethane
Typical spectra of impurities of nitromethane on tricresyl phosphate/diatomite 545 and silicone oil DC703/diatomite 545 chromatographic columns
1—air peak; 2—formaldehyde; 3—acetaldehyde; 4—methanol; 5—water; 6—acetone; 7—unknown peak; 8—ethyl; 9—unknown peak; 10—nitromethane; 11—nitroethane; 12—2-nitropropane; 13—isoamyl alcohol; 14—1-nitropropane. 7
Additional remarks:
HG2031—91
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the technical jurisdiction of the Beijing Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Sichuan State-owned Luzhou Chemical Plant. The main drafters of this standard are Zou Xinchun and Liu Guangwu.
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