GB/T 27563-2011N-Methyl-2-Pyrrolidone for industrial use (English PDF)

3.1 Appearance

It is a colorless or slightly yellow transparent liquid at room temperature.

3.2 Requirements

N-methyl-2-pyrrolidone for industrial use shall meet the technical requirements shown in Table 1.

4.1 Warning

Some test procedures specified in the test method may lead to dangerous situations. Operators shall take appropriate safety and protective measures.

4.2 General provisions

Unless otherwise specified, only analytically pure reagents and grade 3 water as specified in GB/T 6682 are used in the analyses.

Unless otherwise specified, the standard titration solutions used in the analysis shall be prepared in accordance with the provisions of GB/T 601.

4.3 Appearance

Take an appropriate amount of laboratory sample into a colorimetric tube. Observe visually under natural light.

4.4 Determination of N-methyl-2-pyrrolidone content

4.4.1 Method summary

Gas chromatography is used. Under selected chromatographic conditions, the specimen is vaporized and passed through a capillary column to separate the components.

Detection is by flame ionization detection (FID). Quantification is performed using the corrected area normalization method. After subtracting water and total amines, the N- methyl-2-pyrrolidone content is calculated.

4.4.2 Reagents

4.4.2.1 Nitrogen. volume fraction >= 99.995%.

4.4.2.2 Hydrogen. volume fraction >= 99.99%.

4.4.2.3 Air. purified with activated carbon and blue silica gel, then dried.

4.4.2.4 N-methyl-2-pyrrolidone. chromatographically pure.

4.4.2.5 gamma-Butyrolactone. chromatographically pure.

4.4.2.6 1,4-Butanediol. chromatographically pure.

4.4.2.7 2-Pyrrolidone. chromatographically pure.

4.4.3 Instruments

4.4.3.1 Gas chromatograph. equipped with a flame ionization detector (FID). The sensitivity and stability of the instrument shall comply with the requirements of GB/T 9722. The linear range shall meet analytical requirements.

4.4.3.2 Data processing system. chromatography data processor or chromatography workstation.

4.4.3.3 Sample injector. 1.0 µL micro syringe or automatic sample injector.

4.4.4 Chromatographic analysis conditions

4.5 Determination of moisture

The determination shall be carried out in accordance with the provisions of Chapter 8 of GB/T 6283-2008.

The arithmetic mean of the two parallel determination results shall be reported as the result. The absolute difference between the two parallel determination results shall not exceed 0.003%.

4.6 Determination of chromaticity

The determination shall be carried out in accordance with the provisions of GB/T 3143.

4.7 Determination of refractive index

The determination shall be carried out in accordance with the provisions of GB/T 6488.

4.8 Determination of total amine content

4.8.1 Method summary

Dissolve the sample in isopropyl alcohol. Titrate the alkaline substances in the specimen with a standard hydrochloric acid solution. Use a potentiometer or pH meter to indicate the titration endpoint. The total amine content is calculated as monomethylamine.

4.8.2 Reagents

4.8.2.1 Isopropyl alcohol.

4.8.2.2 Standard hydrochloric acid titration solution. c(HCl) = 0.02 mol/L.

4.8.3 Instruments

4.8.3.2 Acidity meter. the accuracy of the acidity meter is pH ± 0.01, with temperature compensation function.

4.8.3.1 Potentiometer. the accuracy of the potentiometer is ±0.01 mV

4.8.4 Analysis steps

Weigh 65 g of laboratory sample to the nearest 0.01 g. Place in a 250 mL beaker.

Dissolve in 100 mL of isopropyl alcohol. Shake well. Perform the following determination according to Chapter 6 of GB/T 9725-2007.

4.8.5 Result calculation

The total amine content is expressed as the mass fraction w2 of monomethylamine (CH3NH2), expressed in %, and calculated according to formula (3).

Where, V - the volume of the standard hydrochloric acid titrant (4.8.2.3) consumed by the test material, in milliliters (mL); c - the exact concentration of the standard hydrochloric acid titrant, in moles per liter (mol/L); m - the mass of the test material, in grams (g);

M - the molar mass of monomethylamine (CH3NH2), in grams per mole (g/mol) (M = 31.06).

The arithmetic mean of the two parallel determination results shall be reported as the result. The absolute difference between the two parallel determination results shall not exceed 0.001%.

4.9 Determination of pH

Use a pipette to transfer 10.0 mL of the sample to a 100 mL volumetric flask. Dilute to the mark with carbon dioxide-free water. Shake well and transfer to a beaker. The following steps shall be performed in accordance with Chapter 6 of GB/T 9724-2007.