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1 Scope
This standard specifies the test methods for amine aqueous solutions in industry
This standard is applicable to the determination of the aqueous solution prepared by methylamine produced by the continuous gas-phase catalytic ammoniation of methanol
2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through quotation in this standard
GB/T6682-1992 Analytical laboratory water specifications and test methods (neq ISO 3696: 1987)
3 Test method
The reagents and water used in this standard, unless other requirements are specified, use analytical reagents and secondary water that meets GB/T6682
3.
Inject 25 mL of methylamine sample into a 50 mL plugged colorimetric tube, and observe sideways under sufficient light
3.
3.
The first step uses hydrochloric acid standard titration solution to determine the total alkalinity of the methylamine aqueous solution; the second step uses gas chromatography to determine the impurities in the solution
3.
3.
3.
3.
3.
Use a 1 mL syringe with a No.
3.
The total alkalinity (X) expressed as the mass percentage of the main amine is calculated according to formula (1):
Where: V——Volume of hydrochloric acid standard titration solution consumed in titration, mL;
C——The actual concentration of hydrochloric acid standard titration solution, mol/L;
m——the mass of the sample, g;
M——The mass of main amine expressed in grams equivalent to 1.
00mL hydrochloric acid standard titration solution [c(HCl)=1.
000mol/L], monomethylamine is 0.
03106, dimethylamine is 0.
04508, and trimethylamine is 0.
05911
.
3.
2.
2.
4 Allowable difference
Take the arithmetic average of the two measurement results as the measurement result
.
The difference between the two parallel determination results is:
Monomethylamine≤0.
06%; Dimethylamine≤0.
09%; Trimethylamine≤0.
12 %
.
Related Links: Determination of Ursolic Acid Purity—High Performance Liquid Chromatography (2)