Determining the Vapor Pressures of Diacetone Diperoxide (DADP) and Hexamethylene Triperoxide Diamine (HMTD)

The vapor signature of diacetone diperoxide (DADP) and hexamethylene triperoxide diamine (HMTD) were examined by a gas chromatography (GC) headspace technique over the range of 15 to 55 °C. Parallel experiments were conducted to redetermine the vapor pressures of 2,4,6‐trinitrotoluene (TNT) and triacetone triperoxide (TATP). The TNT and TATP vapor pressures were in agreement with the previously reported results. Vapor pressure of DADP was determined to be 17.7 Pa at 25 °C, which is approximately 2.6 times higher than TATP at the same temperature. The Clapeyron equation, relating vapor pressure and temperature, was LnP (Pa)=35.9−9845.1/T (K) for DADP. Heat of sublimation, calculated from the slope of the line for the Clapeyron equation, was 81.9 kJ mole⁻¹. HMTD vapor pressure was not determined due to reduced thermal stability resulting in vapor phase decomposition products.     

Gas‐phase Concentration of Triacetone Triperoxide (TATP) and Diacetone Diperoxide (DADP)

The present investigation is about the determination of the gas phase concentration parameters of the notorious explosives triacetone triperoxide (TATP, 1 ) and diacetone diperoxide (DADP, 2 ), which have been frequently used in improvised explosive devices. According to calculations with EXPLO5 the energetic performance of both explosives is similar. The enthalpy of sublimation (298.15 K) ( 1 : 76.7±0.7 kJ mol⁻¹; 2 : 75.0±0.5 kJ mol⁻¹) and vapor pressures (298.15 K) ( 1 : 6.7 Pa, 2 : 26.6 Pa) of both compounds have been studied using the transpiration method in the ambient temperature range of 274–314 K. The results obtained in this work were compared critically with the existing literature values. Data for DADP ( 2 ) mostly shows agreement with literature ones. However data of TATP ( 1 ) obtained in this work revealed insufficient agreement of all sets of data available in literature, which might be explained by the rich polymorphism of TATP 1 . The saturation and diffusion equilibrium concentration of both analytes was calculated at 298.15 K. In comparison to the saturation equilibrium concentration measured in this work ( 1 : 600 μg L⁻¹, 2 : 1589 μg L⁻¹) the corresponding estimated diffusion condition air concentrations ( 1 : 3.1 ng L⁻¹, 2 : 10 ng L⁻¹, for a surface of 200 cm²) are lower by five orders of magnitude.     

Degradation of Triacetone Triperoxide (TATP) Using Mechanically Alloyed Mg/Pd

A heterogenous catalytic system consisting of mechanically alloyed Mg/Pd particles has been used to degrade the peroxide explosive, triacetone triperoxide (TATP). The degradation of the TATP with the Mg/Pd particles (half life of 1.2×10¹ min) was compared to the degradation with microscale Mg particles (half life of 1.7×10³ min) and 10% Pd on activated carbon (half life of 8.7×10² min). Combining the Mg and Pd on carbon (Pd/C) through a mechanical alloying process is shown to produce reactive particles that can be used to degrade TATP. The major product of the degradation of TATP with mechanically alloyed Mg/Pd particles was acetone. A material balance for carbon was also calculated for the degradation reaction with 94±5% (mean±standard deviation) of the TATP carbons accounted for in the production of acetone.     

Factors Influencing Destruction of Triacetone Triperoxide (TATP)

Acid catalyzes the formation of triacetone triperoxide (TATP) from acetone and hydrogen peroxide, but acid also destroys TATP, and, under certain conditions, converts TATP to diacetone diperoxide (DADP). Addition of strong acids to TATP can cause an explosive reaction, while reaction with dilute acid reduces the decomposition rate so drastically that gentle destruction of TATP is impractical. However, combined use of dilute acid with slightly solvated TATP made gentle destruction of TATP feasible. Variables including acid type, concentration, solvent and ratios thereof have been explored, along with kinetics, in an attempt to provide a field‐safe technique for gently destroying this homemade primary explosive. The preferred method is moistening TATP with an alcoholic solution (aqueous methanol, ethanol, or iso‐propanol) followed by addition of 36 wt‐% hydrochloric acid. Preliminary experiments have shown the technique to be safe and effective for destruction of hexamethylene triperoxide diamine (HMTD), as well.     

Factors Influencing Triacetone Triperoxide (TATP) and Diacetone Diperoxide (DADP) Formation: Part I

Conditions, which result in the formation of triacetone triperoxide (TATP) or diacetone diperoxide (DADP) from acetone and hydrogen peroxide (HP, were studied for the purposes of inhibiting the reaction. Reaction of HP with acetone precipitates either DADP or TATP, but the overall yield and amount of each was found to depend on (1) reaction temperature, (2) the molar ratio of acid to HP/acetone, (3) initial concentrations of reactants, and (4) length of reaction. Controlling molar ratios and concentrations of starting materials was complicated because both sulfuric acid and hydrogen peroxide were aqueous solutions. Temperature exercised great control over the reaction outcome. Holding all molar concentrations constant and raising the temperature from 5 to 25 °C showed an increase of DADP over TATP formation and a decrease in overall yield. At 25 °C a good yield of TATP was obtained if the HP to acetone ratio was kept between 0.5 : 1 and 2 : 1. At constant temperature and HP‐to‐acetone held at one‐to‐one ratio, acid‐to‐HP molar ratios between 0.10 : 1 and 1.2 : 1 produced good yield of TATP. Plotting the molality of HP vs. that of sulfuric acid revealed regions, in which relatively pure DADP or pure TATP could be obtained. In addition to varying reaction conditions, adulterants placed into acetone were tested to inhibit the formation of TATP. Because there is much speculation of the relative stability, sensitivity, including solvent wetting of crystals, and performance of DADP and TATP, standard tests (i.e. DSC, drop weight impact, and SSED) were performed.     

Direct Detection of Triacetone Triperoxide (TATP) in Real Banknotes from ATM Explosion by EASI‐MS

In Brazil, automated teller machine (ATM) has become a major target of theft incursions toward explosion. Efficient analysis of explosives residues on suspect banknotes is a serious issue in forensic labs, and guide to the crime solution. Easy ambient sonic‐spray ionization mass spectrometry (EASI‐MS) is shown to be a simple and selective screening tool to identify peroxide explosives on real banknotes collected from ATM explosion. Analyses were carried out directly on the banknotes surfaces without any sample preparation, identifying triacetone triperoxide (TATP) and diacetone diperoxide (DADP). Homemade EASI source was coupled to ultrahigh‐resolution and ultrahigh accuracy FT‐ICR MS and revealed the ion of m /z 245 correspondent to sodiated TATP [C₉H₁₈O₆Na]⁺ and the ion of m /z 171 related to sodiated DADP [C₆H₁₂O₄Na]⁺, ions that is the sodiated DADP and the ions of m /z 173 and 189 related to [C₆H₁₄O₄Na]⁺ and [C₆H₁₄O₄K]⁺, respectively, which are associated to chemical markers of TATP domestic route synthesis. EASI source coupled to a single quadrupole mass spectrometer provides an intelligent and simple way to identify the explosives TATP, DADP and its domestic synthesis markers.     

Taming the Beast: Measurement of the Enthalpies of Combustion and Formation of Triacetone Triperoxide (TATP) and Diacetone Diperoxide (DADP) by Oxygen Bomb Calorimetry

Low‐melting paraffin wax was successfully used as a phlegmatizing agent to perform semi‐micro oxygen bomb calorimetry of spectroscopically pure samples of the sensitive explosive peroxides TATP and DADP. The energies of combustion (Δ_cU) were measured and the standard enthalpies of formation (Δ_fH°) were derived using the CODATA values for the standard enthalpies of formation of the combustion products. Whilst the measured Δ_fH° of DADP (Δ_fH°=−598.5 ± 39.7 kJ mol⁻¹) could not be compared to any existing literature value, the measured Δ_fH° value of TATP (Δ_fH°=+151.4 ± 32.7 kJ mol⁻¹) did not correlate well with the only existing experimental value and confirmed that TATP is an endothermic cyclic peroxide.     

Knudsen Effusion Measurement of Organic Peroxide Vapor Pressures

The vapor pressures of TATP over the temperature range 269.85–306.95 K and DADP over the temperature range 265.85–294.85 K were determined using a modified Knudsen effusion apparatus. The Clausius‐Clapeyron plot of log₁₀(p(Pa)) with 1/T provided a straight line for each material. This expression for TATP is log₁₀(p(Pa))=−(4497±80)/T(K)+(15.86±0.28) (error limits are 95 % confidence limits) and for DADP it is log₁₀(p(Pa))=−(4417±137)/T(K)+(16.31±0.48). These expressions yield values of the vapor pressure at 298.15 K of 6 Pa for TATP and 17 Pa for DADP, and heats of sublimation of 86.2±1.5 kJ mol⁻¹ for TATP and 84.6±2.6 kJ mol⁻¹ for DADP. Attempts were made to determine the vapor pressure of HMTD but it appears to have a vapor pressure too low for our system to reliably determine. A two month experiment did provide an upper limit estimate for the vapor pressure of HMTD of approximately 0.04 Pa at room temperature. Melting point and melting point range were used as verification of the identity and purity of the TATP and DADP used in these experiments, but this was not possible with HMTD since it detonates prior to melting.     

蒸气顶空富集装置-自动顶空气相色谱法在海水中痕量苯系物检测中的应用

采用蒸气顶空富集-自动顶空气相色谱法,研究了海水中痕量苯系物(包括苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯和苯乙烯)的测定方法,优化了蒸气富集作为海水中苯系物预处理方法的参数。对其精馏管长度、回收冷凝液体积、吸收介质等影响富集效果的关键因素进行了评价,并优化了色谱条件,考察方法的精密度和回收率。结果表明,大体积水样经过10 cm长度冷凝管的二次冷凝富集,以水作为吸收剂,1 L水样富集浓缩至10 mL后,可使原有自动顶空气相色谱分析苯系物的灵敏度提高1~2个数量级。采用蒸气顶空富集-顶空气相色谱法测定海水中的苯系物的平均加标回收率为83%~113%,相对标准偏差为1.1%~5.4%(n=3);苯系物的海水中检出限为0.02~0.1μg/L。本文建立的蒸气顶空富集-自动顶空气相色谱法简单快速,重现性好,回收率高,适用于海水中痕量苯系物的分析测定。     

A Determination of the Hansen Solubility Parameters of Hexanitrostilbene (HNS)

The temperature‐dependent solubility of hexanitrostilbene (HNS) [CAS# 20062‐22‐0] was determined in ten solvents and solvent blends using the Tyndall effect. Thermodynamic modeling of the data yielded Flory interaction parameters, the molar enthalpy of mixing, the molar entropy of mixing, and the molar Gibbs energy of mixing. All solutions exhibited endothermic enthalpies and positive entropies of mixing. The presence of water in some of the solvent blends made dissolution increasingly endothermic and disfavored solubility. The solubilities of HNS at 25 °C were used to determine the three‐component Hansen solubility parameters (HSP) (δ_D=18.6, δ_P=13.5, δ_H=6.1 MPa^1/2) and the radius of the solubility sphere (R₀=5.8 MPa^1/2). The HSP determined for HNS using group‐additivity (δ_D=21.0, δ_P=13.3, and δ_H=8.6 MPa^1/2) also correctly predicted the optimum solvents for this explosive.     

Thermally Stable Honeycomb‐Patterned Porous Films of a Poly(L‐lactic acid) and Poly(D‐lactic acid) Stereo Complex Prepared Using the Breath Figure Technique

Porous polymer materials prepared from biodegradable polymers have received considerable attention due to their potential as cell culture scaffolds for tissue engineering. Porous materials are generally sterilized by autoclaving prior to use as cell culture scaffolds to avoid unexpected biological infection. However, the melting point of biodegradable polymers is typically lower than the temperature used in autoclave sterilization. Here, the preparation of honeycomb films comprising a poly(L‐lactic acid) (PLLA) and poly(D‐lactic acid) (PDLA) stereo complex is described and their thermal stabilities are evaluated. The hierarchic photochemical patterning of PLLA/PDLA stereo complex honeycomb‐patterned films by UV‐O₃ treatment is also demonstrated.