Molecular Modelling of Some Explosives and Propellants (original) (raw)
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The Explosive Chemistry of Nitrogen * A Fascinating Journey From 9th Century to the Present
The chemistry behind explosives is marked with the omnipres-ence of the element nitrogen. The discovery of the explosive properties of nitrogen-based compounds comprises many interesting and serendipitous observations made by inquisitive scientists. In this article, we unravel the fascinating history behind the development of explosives from the 9th century to the present. Every country with an army keeps on upgrading the sharpness and power of their arsenal, and in this regard, the role played by the chemists in developing new explosives, and the chemistry behind these explosives are explained in this article. The basic chemical properties of explosives, their classification, comparison and methods of evaluation are explained. The current status of research in making new explosives and the challenges involved in making explosive polyni-trogen compounds such as pentazolates and pentazenium are also illustrated.
Analytica Chimica Acta, 2011
In this work, a method to determine the nitrogen content of nitrocellulose from gunpowders and collodions is proposed. A basic hydrolysis of nitrocellulose with 1.0% (m/v) NaOH at 150 • C during 30 min was carried out for nitrocellulose from gunpowders (after its previous isolation by a protocol optimized by our research group) and from collodion samples. The concentration of nitrate and nitrite ions in the hydrolysate was determined by ion chromatography with suppression and conductimetric detection. The nitrogen content of nitrocellulose was calculated from the values of the concentration of both ions. The quantitative method was evaluated in terms of selectivity, sensitivity, robustness, limits of detection and quantification, and precision, measured as repeatability and intermediate precision. These parameters were good enough to demonstrate the validity of the method and its applicability to the determination of the nitrogen content of nitrocellulose contained in different types of gunpowders (single-and double-base gunpowders, manufactured from 1944 to 1997) and in commercial collodion samples. For gunpowders, the nitrogen content determined with the optimized method was compared with the values reported by the official label of the ammunition (obtained by a digestion/titration method) and errors, by defect, ranging from 1% to 15.2% (m/m) were calculated. The highest errors were obtained for the oldest gunpowders and could be attributed to the loss of nitro groups in the nitrocellulose molecule during aging. For collodion samples, errors could not be calculated since the real nitrogen content for these samples was not given in the label. In addition, the analysis time (2 h for nitrocellulose isolation, 1.5 h for nitrocellulose hydrolysis, and 0.2 h for chromatographic separation) was about 10 times lower than in the digestion/titration method nowadays used for gunpowder samples.
Talanta, 2016
Nitrocellulose (NC) is one of the most common ingredients in explosive mixtures, however because of its non-volatility, its detection using Gas Chromatography-Electron Ionization-Mass Spectrometry (GC-EI-MS) has not been achieved until today. A rapid method for the identification of NC in bulk explosives using GC-EI-MS was developed. The sample preparation is simple and takes place in a test tube, employing standard equipment of a forensics laboratory. The protocol was optimized and applied to seven, both high and low, commercial explosives, which contained the substance of interest. Moreover, three explosives in the absence of NC were tested to cross check for false positives. Fourteen different standard explosive substances that are usually found in explosive mixtures were then employed in order to monitor the effect of the method on these compounds and check for interferences. Results showed that NC was detected, by its trimethylsilyl (TMS) derivatives, in all the explosive mixtures analyzed and no false positives were observed. The proposed method showed selectivity for NC, as it had no interference coming from other ingredients of explosive mixtures. The protocol introduced offers considerable improvement in identifying the individual components of an explosive mixture and contributes in successful classification of explosives.
Nitrocellulose in Propellants: Characteristics and Thermal Properties
Nitrocellulose was discovered, by the German-Swiss chemist C.F. Schönbein, in the first half of the nineteenth century but remains to have a great interest today. Nitrocellulose has a similar aspect to cotton (white and fibrous texture). It is a nitrate cellulose ester polymer with β (1→4) bonds between monomers, produced from the nitration of cellulose. Its chemical formula is [C6H7O2(OH)3 x(ONO2)x]n, where x indicates the hydroxyl groups exchanged by nitro groups. This macromolecule has different applications depending on their degree of nitration. Nitrocellulose with a low degree of nitration is applied in paints, lacquers, varnishes, inks, etc., while nitrocellulose with a high degree of nitration (>12.5%) is used in explosives. Within the nitrocellulose containing explosives are included dynamites and propellants. Propellants containing nitrocellulose are smokeless gunpowders, which are widely used by the international military community for propelling projectiles. Depending...
The Novel Usage of Nitrocellulose as a Propellant of 5.56 mm Bullet
Solid State Phenomena, 2018
Gun powder is predicted to be more expensive in relation to the world oil shortage crisis in the future. However, cellulose (generic chemical formula (C6H10O5) is the carbohydrate that makes up the main structure of plants. It is more economical especially for countries with a lot of natural resources and rain forests like Malaysia. The finding of the study reveals the capability of nitrocellulose as gunpowder. In this research, a comparison of the same mass of nitrocellulose and gunpowder is made to find out which propellant produce longer distance and greater impact. The main objectives of this study are to find out the performance and capability of nitrocellulose extracted from Rhizophora apiculata compared to gunpowder in terms of velocity, calorific value of bullets and kinetic energy produced. The result shows that the nitrocellulose has better performance than gun powder. The new application of smokeless gun powder ensures troops especially snipers hardly being detected by en...
Journal of Chromatography A, 2013
This work is focused on a novel procedure to discriminate nitrocellulose-based samples with nonexplosive and explosive properties. The nitrocellulose study has been scarcely approached in the literature due to its special polymeric properties such as its high molar mass and complex chemical and structural characteristics. These properties require the nitrocellulose analysis to be performed by using a few organic solvents and in consequence, they limit the number of adequate analytical techniques for its study. In terms of identification of pre-blast explosives, mass spectrometry is one of the most preferred technique because it allows to obtain structural information. However, it has never been used to analyze polymeric nitrocellulose. In this study, the differentiation of non-explosive and explosive samples through nitrocellulose fingerprints obtained by capillary electrophoresis was investigated. A batch of 30 different smokeless gunpowders and 23 different everyday products were pulverized, derivatized with a fluorescent agent and analyzed by capillary electrophoresis with laser-induced fluorescence detection. Since this methodology is specific to d-glucopyranose derivatives (cellulosic and related compounds), and paper samples could be easily found in explosion scenes, 11 different paper samples were also included in the study as potential interference samples. In order to discriminate among samples, multivariate analysis (principal component analysis and soft independent modeling of class analogy) was applied to the obtained electrophoretic profiles. To the best of our knowledge, this represents the first study that achieve a successful discrimination between non-explosive and explosive nitrocellulose-based samples, as well as potential cellulose interference samples, and posterior classification of unknown samples into their corresponding groups using CE-LIF and chemometric tools.
Medieval Gunpowder Chemistry, The Firework Book Revisited
Arguably the most important Western source on the early history of gunpowder technology is the late thirteenth century manuscript, Das Fuerwerkbuch. When it was translated into English in 2000, it contained a commentary on the chemistry of many of the formulations given. These were largely dismissed as useless alchemical nonsense which could not work. Although some mysteries remain, much of the formulation can be understood either as contemporary 'best practice' or by comparison with modern pyrotechnic and explosive knowledge. This paper re-examines the underlying chemistry and demonstrates some surprising innovations anticipating much later claims. Note An extended and peer reviewed copy of this paper was published in ICON Vol 21, 2015 available at https://www.jstor.org/stable/24721698?seq=1#page\_scan\_tab\_contents
2002
The safe use of energetic materials has been scientifically studied for over 100 years. Even with this long history of scientific inquiry, the level of understanding of the important deflagration phenomena in accidental initiations of high explosives remains inadequate to predict the response to possible thermal and mechanical (impact) scenarios. The search also continues for improved explosives and propellants that perform well, yet are insensitive. Currently, the most significant uncertainties are in the processes immediately following ignition. Once ignition occurs in an explosive, the question then becomes what the resulting violence will be. The classical view is that simple wave propagation proceeds from the ignition point. Recently, several experiments have elucidated the importance of reactive cracks involved in reaction violence in both thermally ignited experiments and impacted explosives, in contrast to classical assumptions. This paper presents a view of reaction violence, in both thermal and mechanical insults, that argues for the importance of reactive cracks, rather than simple wave propagation processes. Recent work in this area will be reviewed and presented. Initial results involving novel energetic materials will also be discussed. Novel materials may yield insight into the mechanisms involved with rapid deflagration processes.