R. Meyer J. Köhler A. Homburg Explosives

213 Methyl Violet Test
Methylphenylurethane
Methylphenylurethan; Ethyl-N,N-Phenylmethylcarbamat;
méthylphénylurethane
colorless liquid
empirical formula: C10H13O2N
molecular weight: 179.2
boiling point: 250 °C = 482 °F
refractive index nD 20 :1.51558
energy of formation: –538.5 kcal/kg = 2253 kJ/kg
enthalpy of formation:
–564.7 kcal/kg = –2363 kJ/kg
oxygen balance: –218.7%
nitrogen content: 7.82%
Methylphenylurethane is a gelatinizing W Stabilizer especially for
W Double Base Propellants.
Specifications
density (20/4): 1.071–1.090 g/cm 3
boiling analysis: 248–255 °C
= 478– 491 °F
reaction: neutral
Methyl Violet Test
In this test, which was developed in the USA about 50 years ago from
another test known as the German test (testing for visible nitrous
gases at 135 °C), visual inspection of the nitrous gases is replaced by
testing with a strip of paper, impregnated with methyl violet. This test is
performed at 134.5 °C for nitrocellulose and single-base powders and
at 120 °C for multi-base propellants. At the end of the test the violet
dye changes color to blue-green and then to salmon-pink. For singlebase
powder, this color change should not take place after less than
30 minutes and for a multibase powder after less than 60 minutes.
Only highly unstable powders can be detected by this test, therefore
the latter is now rarely used.