On the photochemical phenomenon in TATB

Abstract

TATB (1,3,5 triaminotrinitrobenzene) is a yellow compound that slowly changes to green upon exposure to sunlight. IR, UV-Visible, and ESCA data pertaining to this phenomenon are presented. It is shown that various types of irradiation can induce NO₂ loss, radical formation, or secondary amine production in TATB. Molecular orbital calculations are used to dispute the previously assigned structure of the radical in irradiated TATB.     

Synthesis and characterization of sonochemically-aminated 1,3,5-triamino-2,4,6-trinitrobenzene

Abstract

A novel method has been achieved for the preparation of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) from TCTNB in toluene by animation with ammonium hydroxide solution under the influence of ultrasonic irradiation. Samples of this sonochemically-aminated TATB (FP-TATB) were studied for its powder characteristics. It was found that the arithmetic median diameter (vol%) and BET surface area of FP-TATB are 15 micrometers and 1.2 m²/g, respectively. To evaluate shock initiation, samples of FP-TATB were pressed to high density (1.8g/cc) and subjected to initiation spot-size testing, and the results were compared with those from micronized TATB (UF-TATB), an IHE booster material. Data from this test indicated that the FP-TATB is slightly more sensitive to shock initiation than the UF-TATB as measured by the dent depth of the witness plate.     

Further insights into the discoloration of TATB under ionizing radiation

ABSTRACT

To determine degradation products formed by exposure of TATB to ionizing radiation, a computational and experimental study is presented. Thermochemical and spectral data have been calculated using DFT at the MH06-HF/aug-cc-pVTZ level which suggest the formation of the cation radical derivative of TATB. Irradiated TATB samples showed the widely reported yellow-to-green discoloration, with measured CIE L*, a*, b* and RGB values correlating with total dose. Trace quantities of a mono-furazan derivative were detected by HPLC-MS; the discoloration is not attributed to this, but rather to the presence of a paramagnetic species (i.e., the cation), as detected by ESR measurements. Recrystallized irradiated TATB samples reverted to their original color, further suggesting it is the cation radical that is responsible for color change.     

Numerical modeling of the effect of temperature and particle size on shock initiation properties of HMX and TATB

Abstract

The three-dimensional Eulerian reactive hydrodynamic code 3DE has been used to investigate the effects of particle size (and the remaining void or hole size) and of initial temperature on the shock initiation of heterogeneous explosive charges of HMX and TATB.

Shocks interacting with HMX and TATB containing various hole sizes have been modeled. The void fraction was held at 0.5% while the spherical hole sizes were varied from 5.0- to 0.00005 mm radius. The shock pressure was also varied.

As the hole size in TATB was varied from 5.0 to 0.5 mm, the explosive became more sensitive to shock. Decreasing the hole size to 0.0005 mm resulted in failure of the shock wave to build toward a propagating detonation. This is similar to the results previously reported for TNT.

HMX became more sensitive to shock as the hole size was varied from 0.5 to 0.005 mm. The hole size had to be decreased to 0.0005 mm before the explosive became less shock sensitive. Smaller hole sizes (0.00005 mm) resulted in failure of the shock wave to build to detonation.

At the same density, the most shock-sensitive explosive is the one with particle sizes between coarse and fine material. The shock sensitivity of HMX continues to increase with decreasing hole sizes for hole sizes where TNT or TATB fail.

The shock sensitivity of TATB, TNT, and HMX increases with initial temperature. TATB at 250°C is as shock-sensitive as HMX at 25°C. This is in agreement with experimental observations. The shock sensitivity of HMX is less dependent on temperature than TATB or TNT.     

TATB—Strong basic reactions provide soluble derivatives for a simple,qualitative high explosive spot test

Abstract

Reactions of TATB in aqueous, strongly basic solutions gave metal salts of 1,3,5-trihydroxy-2,4,6-trinitrobenzene (THTNB) also called trinitrophloroglucinol. Thus, we prepared potassium, sodium, and barium salts. The mono- and diammonium salts were prepared by treating THTNB with ammonia and ammonium hydroxide, respectively. Some explosive properties of the salts were evaluated. From the physical characteristics of the salts in various solvents, a spot test was developed for known high explosives (HE) containing TATB.     

Synthesis and properties of some trisubstituted trinitrobenzenes. TATB analogs

Abstract

The preparation of a number of trisubstituted trinitrobenzene derivatives which are structurally related to TATB is described. These compounds were designed to have diversified properties and were characterized with respect to their density and impact sensitivity. Some observations on sensitivity trends in these TATB analogs are discussed.     

Shock initiation of TATB/FEFO formulations

Abstract

The shock initiation properties of transferable insensitive explosive (TIE) formulations based on the solid high explosive, triaminotrinitrobenzene (TATB), and the liquid explosive, bis(2-fluoro-2,2-dinitroethyl) formal (FEFO), are measured by wedge test, embedded particle velocity gauge and embedded manganin pressure gauge techniques and calculated using the Ignition and Growth reactive flow model. These extrudable formulations are demonstrated to be slightly more shock sensitive than the TATB/inert binder explosive, LX-17. However, the TIE formulations are much less sensitive than HMX-based explosives and still qualify as insensitive explosives in safety and hazard tests. The wedge tests showed a very steep dependence of run distance to detonation on the input shock pressure. Embedded gauge and reactive flow modeling results imply that shock initiation begins when a small amount of the solid TATB decomposes rapidly enough to heat the surrounding FEFO to decomposition temperature. The FEFO then reacts rapidly, raising the pressure and temperature sufficiently to cause surface decomposition of the TATB particles at rates comparable to those measured in other TATB-based explosives. An Ignition and Growth reactive flow model for TIE based on these assumptions yields reasonable agreement with the experimental shock initiation data.     

Ion transfer mechanism in pores of semipermeable polymer sensor membranes

Ion transfer in the pores of semipermeable cellulose diacetate membranes during the ultrafiltration of aqueous solutions containing high-molecular-weight compounds (serum proteins) and mineral substances including Cl^?, K⁺, Ca²⁺, and Na⁺ ions is considered. It was found experimentally that the concentrations of not only proteins but also the above ions changed in the course of membrane filtration. A model was proposed for ion transfer in the capillary pores of ultrafiltration membranes, and the numerical values of Ca⁺ and Cl^? transfer parameters in the test systems were obtained.     

A comparison of the shock and static compression curves for four solid explosives

Abstract

For the four explosives, PETN, RDX, HMX, and TATB, comparison is made between published data for Hugoniot curves generated from shock-wave experiments and Hugoniot curves generated from isothermal static compression measurements to 10 GPa. For PETN, the static and shock Hugoniot curves in the pressure-volume plane are in agreement. From this agreement, one can conclude that the shock data for PETN determine the Hugoniot curve for unreacted material. The same conclusion can be drawn for RDX, although there is a phase transition between 4 and 5 GPa. Also for TATB the two types of data agree over their common range (0 to 7 GPa). For HMX the comparison is not as conclusive, but may indicate the presence of a phase transition in HMX above 10 GPa.     

CHARACTERIZATION OF KUWAITI CRUDE TBF-FRACTIONS WITH EMPHASIS ON KINEMATIC VISCOSITY - TEMPERATURE BEHAVIOR

ABSTRACT

Characterization of Kuwaiti crude oil, has been carried out in terms o API gravity, debutanized gravity, total sulfur content, Reid Vapor pressure ash content, heating value, salt content, viscosity SUS, vanadium content a: V2 O5, pour point and analysis of various metals. The true boiling poinl (TBP) fractions of this crude (IBP - 95^° C, 95 - 205^°C, 205 - 260^° C, 260 - 345^° C and 455^° C⁺;) were also characterized in terms of API gravity, total sulfui content, H₂S content, mercaptans content, molecular weight and elementa analyses for total carbon, hydrogen and nitrogen. The kinematic viscosity temperature data have been obtained for 95^°C⁺; TBP fractions for a wide range of temperatures.     

Characterization and Thermal Decomposition of Nanometer 2,2′, 4,4′, 6,6′-Hexanitro-Stilbene and 1,3,5-Triamino-2,4,6-Trinitrobenzene Fabricated by a Mechanical Milling Method

Nanometer 2,2?, 4,4?, 6,6?-hexanitro-stilbene (HNS) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) were fabricated on a high-energy ball mill. The particle sizes of nano-HNS and nano-TATB were 98.4 and 57.8 nm, respectively. An SEM analysis was employed to image the micron morphology of nano-explosives. The particle size distribution was calculated by measuring the size of 300 particles in SEM images. XRD, IR, and XPS analyses were used to confirm whether the crystal phase, molecule structure, and surface elements were changed by the milling process. Thermal decomposition of nano-HNS and nano-TATB was investigated by differential scanning calorimetry (DSC) and thermal-infrared spectrometry online (DSC-IR) analyses. Using DSC traces collected from different heating rates, the kinetic and thermodynamic parameters of thermolysis of raw and nano-explosives were calculated (activation energy (E_K), pre-exponential factor (lnA_K), rate constant (k), activation heat (ΔH^≠), activation free energy (ΔG^≠), activation entropy (ΔS^≠), critical temperature of thermal explosion (T_b), and critical heating rate of thermal explosion (dT/dt)_Tb). The results indicated that nano-explosives were of different kinetic and thermodynamic properties from starting explosives. In addition, the gas products for thermal decomposition of nano-HNS and nano-TATB were detected. Although HNS and TATB are both nitro explosives, the decomposition products of the two were different. A mechanism to explain the difference is proposed.     

Studies on metal salts of 4-(2,4,6 - trinitroanilino) benzoic acid

Abstract

Synthesis, characterization and thermal studies of copper and lead salts of 4-(2,4,6-trinitroanilino) benzoic acid have been carried out. Differential thermal analysis data show that Pb²⁺ and Cu²⁺ salts are stable up to 240 and 260°C respectively and then decompose exothermically. Impact sensitivity value (h₅₀) is 77 cm for lead salt and 170 cm for copper salt. Both the salts are found friction insensitive upto 36 kg. The calorimetric values of lead and copper salts are 679 and 839 cal/g, respectively.     

Palladium nanoparticles on dendrimer-containing supports as catalysts for hydrogenation of unsaturated hydrocarbons

A new method has been proposed for encapsulation of palladium nanoparticles with a size of up to 2.5 nm in the matrix of special supports, the polymer networks based on poly(propylene imine) dendrimers, synthesized for this purpose. It has been shown that the particle size distribution of the materials obtained and their catalytic activity in the hydrogenation reactions of unsaturated compounds substantially depend on the specific features of the support structure. A high activity (TOF up to 15000 h^?1) has been observed in the hydrogenation of styrene. The catalysts can be repeatedly used without loss of activity.     

Lead salt of 2, 4, n-trinitroanilinoacetic acid - an energetic ballistic modifier for double base propellants

Abstract

Lead Salt of 2,4,N-trinitroanilinoacetic acid has been evaluated as ballistic modifier in composite modified double base matrix. Burn rate measurements showed a plateau effect between 3.43 — 8.82 MPa. The salt-containing propellant composition showed a synergistic effect on decomposition of propellants as evidenced by a reduction in differential thermal analysis exotherm peak temperature. Effect of magnesium oxide-lead salt combination on burn rate of propellant formulation was also evaluated. The combination increased the burn rate at 6.86 — 8.82 MPa and decreased at 10.78 MPa. The salt has been prepared by double decomposition of lead nitrate with sodium salt of 2,4,N-trinitroanilinoacetic acid, which in turn is prepared from glycine and 2,4 - dinitrochlorobenzene. The lead salt decomposes at 187°C as shown by differential thermal analysis exotherm. Calorimetric value (+3.14 MJ/kg) of the salt has been calculated. The salt exhibits an impact sensitivity height (h₅₀) of 97.5 cm and friction sensitivity of >36 kg.     

13C NMR STUDIES ON ROADWAY ASPHALTS

ABSTRACT

Roadway asphalt has been characterized by ¹³C NMR and reasonable chemical shift assignments made. An initial analysis of the asphalt samples from the refinery liquid, plant mix. Initial and 18 month cores has been made; however, these roadways have not aged sufficiently to develop correlations with performance.     

Phenol and dihydroxybenzene hydrogenation catalysts based on polyamide dendrimers and rhodium species

Heterogeneous catalysts based on rhodium nanoparticles and first- and second-generation poly(amidoamine) (PAMAM) dendrimers crosslinked with hexamethylene diisocyanate have been synthesized. It has been found that catalyst samples with a particle size of 0.88 to 1.96 nm, depending on the PAMAM dendrimer generation, are effective in the hydrogenation of phenol, hydroquinone, resorcinol, and pyrocatechol (85°C, 30 atm O₂, 2 h). In phenol hydrogenation, the selectivity for cyclohexanone is 100%. Cyclohexanone has not undergone further transformation under the reaction conditions. The main products of dihydroxybenzene hydrogenation have been trans-cyclohexanediols, with their proportion decreasing in the order: resorcinol > hydroquinone > pyrocatechol. The selectivity has been found to be 100% for 1,3-cyclohexanediol, 97–99% for 1,4-cyclohexanediol, and 33–91% for 1,2-cyclohexanediol. The catalysts based on the second-generation dendrimer have shown a high activity in dihydroxybenzene hydrogenation (TOF of 6600 to 35000 h^?1).     

Synthesis OF N,N1-BIS(2–nitro–benzodifuroxanyl) –3,5–dinitro–2,6–diaminopyridine

Abstract

N,N¹-bis(2-nitro-benzodifuroxanyl)-3,5-dinitro-2,6-diaminopyridine has been synthesized from 2,6-diaminopyridine and trinitrotrichlorobenzene, Yields of 80 - 90% were obtained under extremely mild reaction conditions. For this end compound,The structure has been determined by elemental analysis,IR, ¹HNMR, and MS spectroscopies.     

STRUCTURAL STUDIES OF SHORT PATH DISTILLATES AND SUPERCRITICAL FLUID EXTRACT OF PETROLEUM SHORT RESIDUE BY NMR SPECTROSCOPY

Abstract

Four short-path distillates obtained at different evaporator temperatures (240, 270, 300, and 330° C) and a supercritical fluid extract (with CO₂ as solvent) of petroleum short residue (North Gujarat Mix) have been separated into saturates and aromatics. Each fraction of all the said samples has been studied by ¹H- and ¹³C-NMR spectrometry and the distributions of various types of hydrogens and carbons are reported. Several reliable average structural parameters have been computed and their relative variation is discussed.     

Thermal decomposition of RDX: Evidence of a nitronylnitroxyl free radical intermediate

Abstract

The thermal decomposition of RDX produces free radical intermediates which are detected by using ESR (electron spin resonance) spectroscopy. The assignment of certain ESR signals from thermally decomposed RDX and HMX to a nitroxyl radical (RNO·) has been discussed in earlier publications. Spectral data from isotopically labelled RDX (RDX-d₆ and RDX-¹⁵NO₂) supports a nitronylnitroxyl radical (R(N⁺?O^?)NO·) assignment to the ESR signals detected during liquefaction of RDX at 200°C.