This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of industrial dimethylformamide. This standard applies to industrial dimethylformamide produced by the reaction process of methyl formate and dimethylamine. It is mainly used in the pharmaceutical, pesticide, organic chemical and other industries. HG/T 2028-1991 Industrial dimethylformamide HG/T2028-1991 Standard download decompression password: www.bzxz.net

Chemical Industry Standard of the People's Republic of China
HG2028-91
Industrial dimethylformamide
Published on June 26, 1991
Ministry of Chemical Industry of the People's Republic of China
Implementation on January 1, 1992
Chemical Industry Standard of the People's Republic of China
Industrial dimethylformamide
1 Subject content and scope of application
HG2028-91
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of industrial dimethylformamide. This standard applies to industrial dimethylformamide obtained by the reaction process of methyl formate and dimethylamine. It is mainly used in the pharmaceutical, pesticide, organic chemical and other industries.
（CH）2NOCH
Molecular formula
Structural formula
Relative molecular mass 73.09 (according to the 1987 international relative atomic mass) 2. Reference standards
Preparation of standard solutions for titration analysis (volume analysis) Chemical reagents
Preparation of preparations and products used in chemical reagent test methods GB1250
GB3143
GB6283
GB6488
GB6680
GB7534
GB8170
3 Technical requirements
Expression and determination methods of limit valuesColor determination method for liquid chemical products (Hazen unit - one platinum-cobalt number)Determination of water content in chemical productsKarl Fischer method (general method)Determination of refractive index of chemical products
General rules for sampling of liquid chemical products
Rounding rules for determination of boiling range of volatile organic liquids for industrial use
3.1 Appearance: colorless, transparent, oily liquid.
3.2 The quality of industrial dimethylformamide shall meet the requirements of the following table: Item
Chroma, Hazen unit -bzxZ.net
—Pt-Co number)
Distillation test (0℃, 101325Pa) 151~155℃ radium output volume, ml Refractive index,
Water content, %
Acidity (as formic acid) or alkalinity (as dimethylamine), % Approved by the Ministry of Chemical Industry of the People's Republic of China on June 26, 1991 First-class product
1.427~1.429
Qualified product
Implemented on January 1, 1992
4 Test method
HG2028-91
For the reagents and water used in this standard, unless other special requirements are specified, analytically pure reagents and distilled water or water of equivalent purity shall be used. Unless otherwise specified, the standard solutions, preparations and products used in this standard shall comply with the provisions of GB601 and GB603. 4.1 Colorimetry
Perform in accordance with GB3143.
4.2 Distillation test
Perform in accordance with GB7534.
Dimethylformamide boiling point change rate with pressure; K=3.3X10-℃/Pa. 4.3 Refractive index determination
Perform in accordance with GB6488.
4.4 Moisture determination
The sample weight is 2g (accurate to 0.01g), and the others are in accordance with GB6283. The difference between the results of two parallel determinations shall not exceed 0.005%, and the arithmetic mean shall be taken as the determination result. 4.5 Determination of acidity or alkalinity
4.5.1 Summary of method
Use neutral red-bromothymol blue mixed indicator to titrate dimethylformamide aqueous solution with hydrochloric acid or sodium hydroxide standard titration solution to determine the acidity or alkalinity of the sample.
4.5.2 Reagents and solutions
4.5.2.1 Standard hydrochloric acid titration solution: c(HCI) = 0.01 mol/L. 4.5.2.2 Standard sodium hydroxide titration solution: c(NaOH) = 0.01 mol/L. 4.5.2.3 Neutral red-bromothymol blue mixed indicator: 1 g/L neutral red ethanol solution and 1 g/L bromothymol blue ethanol solution are mixed in equal volumes.
4.5.2.4 pH 7.0 distilled water: Use dilute hydrochloric acid (1+1) or dilute ammonium hydroxide (1+1) solution to adjust the distilled water to pH 7.0. 4.5.3 Analysis steps
Use a pipette to transfer 10 mL of the laboratory sample into a conical flask containing 40 mL of distilled water (4.5.2.4), mix well, and add 5 to 6 drops of neutral red-bromothymol blue mixed indicator (4.5.2.3). If the solution is red, it is acidic. Use sodium hydroxide standard titration solution (4.5.2.2) to titrate until the solution changes from red to dark green. This is the end point. If the solution is green, it is alkaline. Use hydrochloric acid standard titration solution (4.5.2.1) to titrate until the solution changes from green to red. This is the end point. Calculate the acidity or alkalinity of the laboratory sample according to the volume of base or acid consumed. 4.5.4 Expression and calculation of results
The mass percentage of acid X (calculated as formic acid) is calculated according to formula (1): X1=V:X 0.046 03 X
10×0.9455
Wherein, V is the volume of the standard sodium hydroxide solution consumed by the sample, mL; c is the actual concentration of the standard sodium hydroxide solution, mol/L; 0.9455 is the density of dimethylformamide, g/cm3; (1)
0.04603 is the mass of formic acid equivalent to 1.00 mL of the standard sodium hydroxide solution [c(Na0H)=1.000 mol/L], expressed in grams.
The mass percentage of alkali X2 (in terms of dimethylamine) is calculated according to formula (2): X = 0X0.045 08 × 100
10X0.9455
HG2028-91
Wherein: V is the volume of the standard hydrochloric acid titration solution consumed by the sample, mLc is the actual concentration of the standard hydrochloric acid titration solution, mol/L; 0.9455 is the density of dimethylformamide, g/cm; 0.04508 is the mass of dimethylamine in grams equivalent to 1.00mL of the standard hydrochloric acid titration solution [c(HC1)=1.000mol/L].
The difference between the results of two parallel determinations shall not be greater than 0.005%, and the arithmetic mean is taken as the determination result. 5 Inspection rules
5.1 Industrial dimethylformamide shall be inspected by the quality supervision department of the manufacturer. The manufacturer shall ensure that all products leaving the factory meet the requirements of this standard. Each batch of products leaving the factory shall be accompanied by a quality certificate in a certain format, which shall include the manufacturer's name, product name, grade, date of issue, batch number, quantity and the number of this standard. 5.2 Product sampling shall be carried out in accordance with the provisions of GB6680. Samples shall be taken evenly from the barrel using a clean and dry sampling tube. The sample volume shall not be less than 1000ml.
5.3 Put the sample in equal amounts into two clean, dry, well-sealed ground-mouth bottles. The labels on the bottles shall indicate the manufacturer's name, product name, batch number, batch size, sampling date, etc. One bottle is for inspection, and the other bottle is sealed and stored for three months for future reference. 5.4 The user shall accept the dimethylformamide products received within three months from the date of leaving the factory in accordance with the technical conditions, inspection rules and test methods specified in this standard.
5.5 If one of the indicators in the test results does not meet the requirements of this standard, the sample should be re-tested from the barrel with twice the amount according to Article 5.2. If one of the indicators in the test results still does not meet the requirements of this standard, the batch of products shall be unqualified. 5.8 The judgment of the test results shall be carried out according to the rounded value comparison method in GB1250, and the rounding shall be carried out according to GB8170. 5.7 When the manufacturer and the user have objections to the product quality, the two parties shall negotiate to resolve or ask the arbitration unit to conduct arbitration analysis. The inspection shall be carried out according to the inspection method specified in this standard.
6 Marking, packaging, transportation and purchase and storage
6.1 The packaging barrel of industrial dimethylformamide shall be clearly marked with: manufacturer name, product name, registered trademark, product grade, manufacturing date, production batch number, standard number and net weight.
6.2 Industrial dimethylformamide is packaged in plastic-sprayed barrels, aluminum barrels or iron barrels. 6.3 Industrial dimethylformamide is easy to absorb water and catch fire. It is required to be moisture-proof, leak-proof and fire-proof during transportation and marked with corresponding signs. 6.4 Industrial dimethylformamide should be stored in a cool, dry, clean and ventilated warehouse. Additional remarks:
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 jurisdiction of the Beijing Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Lianyungang Shuguang Chemical Factory. The main drafters of this standard are Dai Xiao and Huang Xiuzhen. 3
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