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.     

The effects of radiation on (1,3,5 - triamino - 2,4,6 - trinitrobenzene) TATB studied by time-of-flight secondary ion mass spectrometry

Abstract

Highly Charged Ion (HCI) Time-of-Flight (TOF) Secondary Ion Mass Spectrometry (SIMS) has been employed to analyze the changes in the surface composition of TATB caused by low energy electron, ultraviolet, and Gamma ray irradiation. Comparisons are made between canary yellow (not irradiated) TATB and TATB that has been “greened” by exposure to radiation. We ascribe the color change from yellow to green to a loss of oxygen. Another striking aspect of this study is the presence of a feature at m/z = 30 (NO⁺) for highly charged ion SIMS, which does not occur in singly charged ion TOF SIMS.     

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.     

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.     

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.     

Discoloration of Hydrotreated Naphthenic Rubber Base Oil at High Temperature

Abstract

In this article, the reasons for discoloration of hydrotreated naphthenic rubber base oil under high temperature were studied in detail. In order to define compositional factors associated with the color deterioration, firstly liquid-solid chromatography was used to separate hydrotreated naphthenic rubber base oil into five different fractions, i.e., saturates, monoaromatics, diaromatics, polyaromatics, and polars. Then color change of each fraction was evaluated under high temperature. The results of the test indicate that polyaromatics and polars are the main precursor of color and deposits, respectively, and the composition of polyaromatics was characterized by elemental analysis, gas chromatography mass spectrometry (GC-MS) and atmospheric pressure chemical ionization mass spectrometer (APCI/MS).     

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.     

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.     

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.     

Chemical behavior of 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, and related compounds as a key to understanding specifics of radiation-chemical processes: 3. The structure of 5-vinyl-2-norbornene and 2-vinylnorbornane radical cations

Cyclic and distonic forms of radical cations were recorded by ESR in x-ray irradiated frozen solutions (1.0 vol %) of 5-vinyl-2-norbornene (VNB) and 2-vinylnorbornane in Freon 113 (CFCl₂CF₂Cl). In both cases, mixtures of isomers in a ratio of endo-: exo-= 66: 34 were used. It was shown that, in the general case, the endo-VNB radical cation rearranges into the radical cation of cis-3a,4,7,7a-tetrahydroindene through a multistage mechanism involving the intermediate formation of the distonic radical cation, not via the earlier suggested one-stage concerted mechanism. The interconversions of endo-and exo-VNB in γ-irradiated solutions of VNB in CCl₄ were studied chromatographically. A general scheme of VNB transformations with allowance for the intermediate formation of the cyclic and distonic forms of the VNB radical cations is proposed. It was found that the structures of the radical cation distonic form and VNB homopolymer are identical, a resemblance that indicates the occurrence of VNB polymerization via the radical cation mechanism during its γ-irradiation.     

CHARACTERIZATION OF LAKHRA COAL BY TG/DTG

ABSTRACT

Non-isothermal thermogravimetry (Tg) and derivative thermogravimetry (DTG) studies are reported on a Pakistan lignite and Pakistan subbituminous coal. The burning profiles of the samples shows multi-peak configuration which is indicative of the heterogeneity of organic matter. The volatile matter profiles of these samples are characterized by rate of weight loss.     

Efficacy of lactic acid in reducing foodborne pathogens in minimally processed lotus sprouts

Fresh lotus sprout is easily browned and perishable due to microbial growth and degradation. Therefore, browning and foodborne pathogen have become the most serious problems. The objective of this study was to investigate the effect of lactic acid (0.25%, 0.5%, 1% and 2% (v/v)) on reduction of foodborne pathogens, such as Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes, in lotus sprouts. Tap water and sodium hypochlorite (200 mg/l) were used as control treatments. Results indicated that tap water caused a slight reduction (<0.5 log) in the microbial loads. The sodium hypochlorite treatment led to 1.3 log reductions of the microbial population. When treated with 0.5% and 2.0% lactic acid solutions, 1.5 and 2.3 log reductions were achieved, respectively. The effectiveness of lactic acid treatment increased with the increase of lactic acid concentration. Results showed that the lactic acid treatment at 0.5% or higher was effective to reduce foodborne pathogens in lotus sprouts. The L* values of samples treated with lactic acid decreased slightly during storage. Furthermore, the lactic acid treatment contributed to slow accumulation of red color on lotus sprouts, which was more effective than sodium hypochlorite treatment to reduce the discoloration of lotus sprouts. These results indicated that lactic acid can be used to improve the color and safety of minimally processed lotus sprouts.     

Study of the Desulfurization Effect of the Novel FS-A1 Desulfurizer

Abstract

A thiadiazole derivative as an environmentally friendly anti-corrosion additive was composed to obtain a new desulfurization agent called FS-A1 using the silver strip corrosion test for jet fuel, the anti-corrosion effect was discussed while the inhibitor was added in jet fuel, blending oil-like and the model oil samples, respectively. The results showed that FS-A1 inhibitor had a good desulfurization effect on jet fuel when the volume ratio of desulfurizer to oil was 1.7%, with a desulfurization rate of more than 96%.     

FREE RADICALS FORMED IN HYDROTREATED COAL LIQUID AND INFLUENCE OF OXYGEN

ABSTRACT

The behavior of radicals formed in hydrotreated coal liquid with heat treatment and the influence of oxygen have been investigated by electron spin resonance (e.s.r.) spectroscopy. A set of e.s.r. spectral lines identified as phenalenyl radical appears from 50^°C as the oil is heated in argon atmosphere. The radical concentration is enhanced with temperature, reaches a maximum between 130 and 150^°C and then decreases at higher temperatures. The radical is very stable even at 200^°C for the sample hydrotreated under mild condition, whereas the radical in the sample treated under severe conditions disappears drastically from 150^°C. When oxygen is introduced in the oil, the radical is converted into semiquinone and/or aryloxy radicals and stable molecules. The treatment in the presence of oxygen at higher temperatures is considered to accompany the formation of other aryloxy radicals by the reaction of aromatic hydrocarbons and oxygen.     

Sensitivity of 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide

ABSTRACT

The thermal and shock sensitivities of plastic bonded explosive formations based on 2,6-diamino-3,5-dinitropyrazine-1-oxide (commonly called LLM-105 for Lawrence Livermore Molecule #105) are reported. The One-Dimensional Time to Explosion (ODTX) apparatus was used to generate times to thermal explosion at various initial temperatures. A four-reaction chemical decomposition model was developed to calculate the time to thermal explosion versus inverse temperature curve. Three embedded manganin pressure gauge experiments were fired at different initial pressures to measure the pressure buildup and the distance required for transition to detonation. An Ignition and Growth reactive model was calibrated to this shock initiation data. LLM-105 exhibited thermal and shock sensitivities intermediate between those of triaminotrinitrobenzene (TATB) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX).     

A New Approach for Computing Pressure Derivative in Well Test Analysis

Abstract

Analysts commonly use the pressure derivative to identify flow regimes and well test interpretation models in pressure-transient test analysis. This article developed a novel adaptive smoothing algorithm by recursive differentiation–integration to improve the pressure derivative calculation. Our method can efficiently suppress measurement errors and produce smooth pressure derivatives from well test data. Equally important, it can prevent oversmoothing of the data by avoiding inappropriate use of large window size, and it can preserve the characteristic behavior of the pressure derivative. We validate our approach with a synthetic case and demonstrate its applicability to actual field examples.     

Moisture absorption by JA2 gun propellant under extreme conditions

Abstract

JA2 propellant downloaded from a 120-mm tank round that had been subjected to conditioning at high temperature and humidity was observed to be discolored and covered with an unknown liquid. Analysis of the propellant indicated a decrease in the nominal diethylene glycol dinitrate (DEGDN) plasticizer content. The nitroglycerine (NG) content was not observed to deviate significantly from its nominal level. The cause of the discoloration of the propellant was traced to its high moisture content. The liquid covering the material was determined to be a mixture of water and DEGDN. In follow-up experiments it was     

SOLID ORGANIC DEPOSITION DURING GAS INJECTION STUDIES

ABSTRACT

Recently a series of first contact miscibility (swelling) experiments have been performed on undersaturated light and heavy oils using LPG rich and methane rich injection gases, in which solid organic deposition was observed. A compositional gradient in the oils during the gas injection process was also evident as oil fractions expelled from the top to bottom of the PVT cell were observed to vary in density, molecular weight, as well as darkness of color. The change in stability of the oil samples before and after the contact with gas was analyzed using flocculation threshold titration. The asphaltene content of the different oil samples were determined by the IP 143 method. The standard asphaltenes and the solid organic deposit recovered from the swelling tests were analyzed using FTIR, HPLC-SEC and ¹H NMR. The aim of these analyses is to reveal the molecular nature of the deposits formed during the gas injection process in comparison with the standard asphaltenes in order to understand the mechanisms involved in asphaltene deposition.     

A NEW LOOK AT THE MECHANISMS OF OXIDATIVE SEDIMENT FORMATION IN FUELS

ABSTRACT

Alkylpyrroles have been known to promote sediment formation and discoloration of petroleum distillates for over thirty years. There has been much effort directed towards understanding the detailed mechanism of alkylpyrrole promoted sediment formation in petroleum distillates. In addition, recent studies have investigated the mechanism of alkylpyrrole sediment formation in shale derived synfuels. It is the intent of this article to critically review some of the postulated mechanisms for alkylpyrrole promoted sediment formation in fuels and then to comment on the significance of these mechanisms to our overall understanding of the field of oxidative fuel stability.     

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.