Robert Matyáš

Sensitivity to friction for primary explosives

The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature.

Power of TATP based explosives

The power of various explosive mixtures based on triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP), ammonimum nitrate (AN), urea nitrate (UrN) and water (W), namely TATP/AN, oil/AN, TATP/UrN, TATP/W and TATP/AN/W, was studied using the ballistic mortar test. The ternary mixtures of TATP/AN/W have relatively high power in case of the low water contents. Their power decrease significantly with increasing the water content in the mixture to more than 30%.

Thermal behavior and decomposition kinetics of ETN and its mixtures with PETN and RDX

Erythritol tetranitrate (butane-1,2,3,4-tetrayl tetranitrate, ETN) has become one of the most synthesized improvised explosives nowadays as it can be found on public internet discussion boards. However, the low melting point, nitrocellulose gelling ability, high energy content, and availability of its precursor make the substance potentially useful in industry as an energetic component or additive in certain gun propellants. Mixtures of ETN with other high explosives are also frequently discussed on web pages dealing with improvised explosives. This article describes thermal behavior and decomposition kinetics of pure ETN and its mixtures with pentaerythritol tetranitrate and cyclonite (1,3,5-trinitro-1,3,5-triazinane, RDX). The thermal behavior and decomposition kinetics of such mixtures are described using non-isothermal DSC and TG techniques. Kissinger method, Soviet manometric method, and modified Kissinger–Akahira–Sunose method were used for data evaluation.

Analytical Characterization of Erythritol Tetranitrate, an Improvised Explosive†

Erythritol tetranitrate (ETN), an ester of nitric acid and erythritol, is a solid crystalline explosive with high explosive performance. Although it has never been used in any industrial or military application, it has become one of the most prepared and misused improvise explosives. In this study, several analytical techniques were explored to facilitate analysis in forensic laboratories. FTIR and Raman spectrometry measurements expand existing data and bring more detailed assignment of bands through the parallel study of erythritol [15N4] tetranitrate. In the case of powder diffraction, recently published data were verified, and 1H, 13C, and 15N NMR spectra are discussed in detail. The technique of electrospray ionization tandem mass spectrometry was successfully used for the analysis of ETN. Described methods allow fast, versatile, and reliable detection or analysis of samples containing erythritol tetranitrate in forensic laboratories.

Synthesis and properties of acetamidinium salts

BackgroundAcetamidines are starting materials for synthesizing many chemical substances, such as imidazoles, pyrimidines and triazines, which are further used for biochemically active compounds as well as energetic materials. The aim of this study was to synthesise and characterise a range of acetamidinium salts in order to overcome the inconvenience connected with acetamidinium chloride, which is the only commercially available acetamidinium salt.ResultsAcetamidinium salts were synthesised and characterised by elemental analysis, mass spectrometry, NMR and - in the case of energetic salts - DTA. The structures of previously unknown acetamidinium salts were established by X-ray diffraction analysis. Hygroscopicities in 90% humidity of eight acetamidinium salts were evaluated.ConclusionsThe different values of hygroscopicity are corroborated by the structures determined by X-ray analysis. The acetamidinium salts with 2D layered structures (acetamidinium nitrate, formate, oxalate and dinitromethanide) show a lack of hygroscopicity, and the compounds with 3D type of structure (acetamidinium chloride, acetate, sulphate and perchlorate) and possessing rather large cavities are quite hygroscopic.

Decreasing Friction Sensitivity for Primary Explosives

Primary explosives are a group of explosives that are widely used in various initiating devices. One of their properties is sufficient sensitivity to initiating stimuli. However, their sensitivity often introduces a safety risk during their production and subsequent handling. It is generally known that water can be used to desensitize these compounds. The most commonly used industrial primary explosives (lead azide, lead styphnate, tetrazene, and diazodinitrophenol) were mixed with water in various ratios and the sensitivity to friction was determined for all mixtures. It was found that even a small addition of water (5–10%) considerably lowered the friction sensitivity.

Tetrazole Ring-Containing Complexes

Heterocycles with high nitrogen content (triazoles and tetrazoles) have been studied by researchers of energetic materials for a very long time. The triazole derivatives were found to be useful in the area of secondary explosives and propellants, while tetrazole compounds were found to have some potential in priming. Heavy metal salts of a variety of tetrazole derivatives were examined in early studies and some even found practical applications.

EXPRESS: Determination of Triacetone Triperoxide and Hexamethylene Triperoxide Diamine in Various Matrices Using Infrared Spectroscopy

The method for quantitative analysis of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) in different matrices is presented. The method is suitable for polymer, plastic, or cellulose matrices. It is based on dissolving, or extraction of, peroxide in the solvent and measurement in cuvettes using the Fourier transform infrared technique. These methods may be useful in analytical techniques of explosive detection and determination.

Explosive Properties of Primary Explosives

The main requirements for primary explosives are sensitivity within useful limits, high initiating efficiency, reasonable fluidity, resistance to dead-pressing, and long-term stability. Useful limits mean that the substance must be sensitive enough to be initiated by an SII but not too sensitive as to be unsafe for handling or transportation. The initiating efficiency, perhaps the most important parameter, determines the ability of a primary explosive to initiate secondary explosives. The reasonable free flowing properties are important for manufacturing where the primary explosives are often loaded volumetrically. Primary explosives must not undergo desensitization when pressed thereby yielding a dead-pressed product. The long-term stability and compatibility with other components, even at elevated temperatures, are essential because primary explosives are often embedded inside more complex ammunition and are not expected to be replaced during their service life. They must also be insensitive to moisture and atmospheric carbon dioxide. Parameters important for secondary explosives such as brisance, strength, detonation velocity, or pressure are of lesser importance to primary explosives although they are of course related to the above properties.

Salts of Benzofuroxan

The furoxan ring (furazan oxide; 1,2,5-oxadiazole 2-oxide) in a molecule is a sensitizing structure which produces a similar sensitizing effect as, for example, an azido group. The presence of the furoxan ring itself, however, is not sufficient to sensitize any compound to a point where it would be useful as a primary explosive. Even the sensitivity of benzotrifuroxan (BTF), representing a molecule with the highest possible number of furoxan groups present on an aromatic ring, is insufficient and places the substance among secondary explosives—between PETN and RDX to be exact [1]. Metallic salts are much more sensitive and possess the necessary properties to be considered as primary explosives.