Determination of sublimation rate of 2,4,6-trinitrotoluene (TNT) nano thin films using UV-absorbance spectroscopy

Hikal, Walid M.; Weeks, Brandon L.

doi:10.1007/s10973-011-1888-8

Cited by 23 publications

(21 citation statements)

References 18 publications

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“…An accuracy of 0.32 LU in the standard deviation is achieved by incorporating the vapor pressure correction, compared to 1.57 LU accuracy from direct COSMO-RS calculations (which we again note are for a supercooled liquid). The list in Table 1 (9) where the vapor pressure is in mbar and the temperature T is in kelvin. These A, B, and C parameters are given in the Supporting Information and allow analytic evaluation of the QSPR-modified calculated vapor pressure curves of all explosives considered here.…”

Section: Resultsmentioning

confidence: 99%

Predicting Temperature-Dependent Solid Vapor Pressures of Explosives and Related Compounds Using a Quantum Mechanical Continuum Solvation Model

Alnemrat

Hooper

2013

J. Phys. Chem. A

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Temperature-dependent vapor pressures of solid explosives and their byproducts are calculated to an accuracy of 0.32 log units using a modified form of the conductor-like screening model for real solvents (COSMO-RS). Accurate predictions for solids within COSMO-RS require correction for the free energy of fusion as well as other effects such as van der Waals interactions. Limited experimental data on explosives is available to determine these corrections, and thus we have extended the COSMO-RS model by introducing a quantitative structure−property relationship to estimate a lumped correction factor using only information from standard quantum chemistry calculations. This modification improves the COSMO-RS estimate of ambient vapor pressure by more than 1 order of magnitude for a range of nitrogen-rich explosives and their derivatives, bringing the theoretical predictions to within typical experimental error bars for vapor pressure measurements. The estimated temperature dependence of these vapor pressures also agrees well with available experimental data, which is particularly important for estimating environmental transport and gas evolution for buried explosives or environmentally contaminated locations. This technique is then used to predict vapor pressures for a number of explosives and degradation products for which experimental data is not readily available.

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Section: Resultsmentioning

confidence: 99%

Predicting Temperature-Dependent Solid Vapor Pressures of Explosives and Related Compounds Using a Quantum Mechanical Continuum Solvation Model

Alnemrat

Hooper

2013

J. Phys. Chem. A

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“…A number of techniques have been developed to monitor the sublimation of particles or films of explosives including thermogravimetry (TG), quartz crystal microbalance (QCM), atomic force microscopy (AFM), UV-absorbance spectroscopy, and photomicroscopy image analysis [16][17][18][19][20] . There are advantages and disadvantages to each of these techniques, the discussion of which is beyond the scope of this current paper.…”

Section: Photomicroscopy and Image Analysis Of Particles Used To Monimentioning

confidence: 99%

Advances in sublimation studies for particles of explosives

et al. 2015

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When handling explosives, or related surfaces, the hands routinely become contaminated with particles of explosives and related materials. Subsequent contact with a solid surface results in particle crushing and deposition. These particles provide an evidentiary trail which is useful for security applications. As such, the opto-physico-chemical characteristics of these particles are critical to trace explosives detection applications in DOD or DHS arenas. As the persistence of these particles is vital to their forensic exploitation, it is important to understand which factors influence their persistence. The longevity or stability of explosives particles on a substrate is a function of several environmental parameters or particle properties including: Vapor pressure, particle geometry, airflow, particle field size, substrate topography, humidity, reactivity, adlayers, admixtures, particle areal density, and temperature. In this work we deposited particles of 2,4-dinitrotoluene on standard microscopy glass slides by particle sieving and studied their sublimation as a function of airflow velocity, areal particle density and particle field size. Analysis of 2D microscopic images was used to compute and track particle size and geometrical characteristics. The humidity, temperature and substrate type were kept constant for each experiment. A custom airflow cell, using standard microscopy glass slide, allowed in-situ photomicroscopy. Areal particle densities and airflow velocities were selected to provide relevant loadings and flow velocities for a range of potential applications. For a chemical of interest, we define the radial sublimation velocity (RSV) for the equivalent sphere of a particle as the parameter to characterize the sublimation rate. The RSV is a useful parameter because it is independent of particle size. The sublimation rate for an ensemble of particles was found to significantly depend on airflow velocity, the areal density of the particles, and the particle field size. To compare sublimation studies these parameters must be known.

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“…The aqueous solubility is also important for explosive detection; a primary transport mechanism for vapors from buried explosives or landmines is upward advection due to evaporation of soil water [10]. Accurate solubility data, including the effects of inorganic salts in saline environments, are needed to understand the fate, extraction, and detection of these compounds [1,10,13,[17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Predicting Solubility of Military, Homemade, and Green Explosives in Pure and Saline Water using COSMO‐RS

Alnemrat

Hooper

2013

Propellants Explo Pyrotec

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The conductor‐like screening model for real solvents (COSMO‐RS) has previously been shown to give accurate aqueous solubilities for a range of organic compounds using only quantum chemical simulation data. Application of this method for solid organic explosives, however, faces two difficulties; it requires correction for the free energy of fusion (a generally unknown quantity for these compounds) and it shows considerable error for common explosive classes such as nitramines. Herein we introduce a correction factor for COSMO‐RS that is applicable to a wide range of explosives, and requires no data beyond a quantum chemistry calculation. This modification allows COSMO‐RS to be used as a predictive tool for new proposed explosives or for systems lacking experimental data. We use this method to predict the temperature‐dependent solubility of solid explosives in pure and saline water to an average accuracy of approximately 0.25 log units at ambient temperature. Setschenow (salting‐out) coefficients predicted by this method show considerable improvement over previous COSMO‐RS results, but are still slightly overestimated compared to the limited experimental data available. We apply this method to a range of military, homemade, and “green” explosives that lack experimental seawater solubility data, an important property for environmental fate and transport modeling.

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Determination of sublimation rate of 2,4,6-trinitrotoluene (TNT) nano thin films using UV-absorbance spectroscopy

Cited by 23 publications

References 18 publications

Predicting Temperature-Dependent Solid Vapor Pressures of Explosives and Related Compounds Using a Quantum Mechanical Continuum Solvation Model

Predicting Temperature-Dependent Solid Vapor Pressures of Explosives and Related Compounds Using a Quantum Mechanical Continuum Solvation Model

Advances in sublimation studies for particles of explosives

Predicting Solubility of Military, Homemade, and Green Explosives in Pure and Saline Water using COSMO‐RS

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