New protocol for the isolation of nitrocellulose from gunpowders: utility in their identification.
In this work, a new approach for the isolation of nitrocellulose from smokeless gunpowders has been developed. A multistep solvent extraction method was needed to purify nitrocellulose contained in gunpowders. For single-base or double-base gunpowders six consecutive solvent extractions were selected: three extractions with methanol (to remove nitroglycerin, 2,4-dinitrotoluene, ethyl-centralite, diphenylamine, and diphenylamine derivatives); one extraction with dichloromethane (to remove colorants and plasticizers of organic nature); one extraction with methanol (to facilitate a final polar extraction); and one extraction with water (to remove ionic components) were necessary at 35 degrees C. For the triple-base gunpowder studied, eight solvent extractions were needed due to a high concentration of the water-soluble nitroguanidine was present. In addition to the same five initial phases used for the single-base and double-base gunpowders, three water extraction phases at a higher temperature (75 degrees C instead of 35 degrees C) were also needed. A final step to solubilize nitrocellulose in methyl ethyl ketone was used to remove inert components (mainly graphite). Nitrocellulose isolated from these propellants was characterized by Fourier-Transformed Infrared Spectroscopy (FTIR spectroscopy). The same FTIR spectra were observed for nitrocelluloses isolated from different types of gunpowders. A comparison of FTIR spectra of nitrocellulose samples of different nitration degree evidenced that the bands regions most affected by this factor were: 3600-3400cm(-1), corresponding to the stretching vibrations of residual hydroxyl groups; 1200-1000cm(-1), attributed to the valence vibrations nuCO of the glucopyranose cycle; and 750-690cm(-1), assigned to vibrations of the nitrate group. In both cases, the bands appearing in these regions were more pronounced in the spectra of nitrocellulose samples of low nitration degree.
López-López
María
M
University Institute of Research in Police Sciences (IUICP), Planta Piloto de Química Fina, Universidad de Alcalá, Ctra. Madrid-Barcelona Km. 33.600, Alcalá de Henares (Madrid), Spain.
de la Ossa
María Angeles Fernández
MA
Galindo
Jorge Sáiz
JS
Ferrando
Jose Luis
JL
Vega
Alfonso
A
Torre
Mercedes
M
García-Ruiz
Carmen
C
D002224:Carbanilides / Q000032:analysis; D002623:Chemistry Techniques, Analytical; D002851:Chromatography, High Pressure Liquid; D003101:Collodion / Q000032:analysis* / Q000737:chemistry; D004136:Dinitrobenzenes / Q000032:analysis; D004159:Diphenylamine / Q000032:analysis; D053834:Explosive Agents / Q000032:analysis*; D007659:Ketones; D000432:Methanol / Q000737:chemistry; D008956:Models, Chemical; D005996:Nitroglycerin / Q000032:analysis; D012997:Solvents / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors
D002224:Carbanilides; D004136:Dinitrobenzenes; D053834:Explosive Agents; D007659:Ketones; D012997:Solvents; C012900:N,N'-diethylcarbanilide; C016403:2,4-dinitrotoluene; D003101:Collodion; D004159:Diphenylamine; D005996:Nitroglycerin; D000432:Methanol