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: 3600-3400 cm(-1), corresponding to the stretching vibrations of residual hydroxyl groups: 1200-1000 cm(-1), attributed to the valence vibrations nu CO of the glucopyranose cycle: and 750-690 cm(-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 (C) 2010 Elsevier B.V. All rights reserved.