129-66-8

The novel, thermally stable explosive 5,5′-bis(2,4,6-trinitro-phenyl)-2,2′-bi(1,3,4-oxadiazole) (TKX-55) is reported. This compound can be prepared by means of a facile synthetic procedure and shows outstanding properties (detonation velocity, detonation pressure, sensitivity toward mechanical stimuli, and temperature of decomposition). TKX-55 was isolated and characterized by means of mass spectrometry, multinuclear (1H, 13C) NMR spectroscopy, and vibrational spectroscopy (IR and Raman). The structure in the crystalline state was determined by low-temperature single-crystal X-ray diffraction. From the calculated standard molar enthalpy of formation (CBS-4M) and the densities, the Chapman-Jouguet detonation properties were predicted by using the EXPLO5 V6.01 thermochemical computer code. The sensitivity of TKX-55 towards impact, friction, and electrostatic discharge was determined. The shock reactivity (explosiveness) of TKX-55 was measured by applying the small-scale shock reactivity test.

Radiolysis of aqueous solutions of TNT was examined to provide fundamental information concerning the reactions of TNT with radical species in water. χ-Radiation was used in conjunction with radical scavengers to compare yields for radiation-induced TNT transformation under oxidizing end reducing conditions and in the presence and absence of oxygen. Pulse radiolytic techniques were employed to determine rate constants and absorption spectra for the reactions of TNT with the hydroxyl radical and the aqueous electron. TNT was rapidly transformed under both reducing (1% tert- butyl alcohol, N2 sparged) and oxidizing (N20 sparged) conditions although rates under reducing conditions were greater. The initial yield for transformation of a 350 μmol L-1 TNT solution under reducing conditions was 0.14 μmol/J as opposed to 0,10 μmol/J measured in oxidizing conditions. The reactions of TNT with reduced oxygen species were found to be highly inefficient in aqueous solution. Although TNT is transformed by both oxidizing and reducing radicals, TNT degradation yields in the absence of a radical scavenger were low, indicating that under these conditions there were significant secondary reactions in which the species resulting from reactions between TNT and the primary radicals further reacted to reform the parent compound. The bimolecular rate constant for the reaction between TNT and ·OH was determined to be 4.3 x 108 mol-1 s-1. Byproduct analyses from χ- radiolysis suggest that hydroxyl radical abstraction of a methyl hydrogen to form the trinitrotoluyl radical is an initial oxidative reaction. The bimolecular rate constant for the reaction between TNT and e(aq)- was measured as 3.5 x 1010 mol-1 s-1. These results provide quantitative and qualitative insight into the reactions between TNT and the various aqueous radicals produced in many remediation processes. A study of aqueous trinitrotoluene (TNT) solutions radiolysis with gamma radiation in conjunction with radical scavengers provides insights into the reactions between TNT and the various aqueous radicals produced in many remediation processes. TNT was rapidly transformed under both reducing and oxidizing conditions, although rates under reducing conditions were higher. Low TNT degradation yields in the absence of a radical scavenger indicate secondary reactions in which the species resulting from reactions between TNT and the primary radicals further reacted to reform the parent compound. Byproduct analyses suggest that OH radical abstraction of a methyl hydrogen to form the trinitrotoluyl radical is an initial oxidative reaction.

An effect of boric acid additives on oxidation of 2,4,6-trinitrotoluene (TNT) to 2,4,6-trinitrobenzoic acid (TNBA) with chromic anhydride in concentrated (96—100%) H2SO4 has been studied. In the presence of tetrahydrosulfatoboric acid HB(HSO4)4 formed in situ (up to 5 mol.%) or added as a preliminary prepared solution (up to 1 mol. %), TNT is selectively oxidized to TNBA in the yields up to 95—99%. The mechanism including formation of TNT dication as a key step of its oxidation at the methyl group has been suggested.

The invention relates to a novel synthesis process of 2, 4, 6-trinitrobenzoic acid, which comprises the following steps: firstly preparing an alcoholic solution of 2, 4, 6-trinitrotoluene, then mixing the alcoholic solution of 2, 4, 6-trinitrotoluene, sodium hydroxide, a catalyst and an oxidizing agent for reaction, filtering, washing and drying the obtained filter cake, dissolving the filter cake in water, adjusting the pH value, standing, filtering, extracting the filtrate with an organic solvent, and finally, evaporating the extract liquor, and naturally drying at normal temperature to obtain the 2, 4, 6-trinitrobenzoic acid. The method provided by the invention has the advantages of good safety, small environmental pollution, simple process, low cost and the like, avoids the use of toxic and harmful substances such as potassium/sodium dichromate, potassium perchlorate, potassium chlorate and the like, and solves the problems of high toxicity, serious environmental pollution, low process safety, high equipment corrosion, high production cost and the like in the existing process.

The invention discloses a one-step chemical catalytic synthesis method of high-purity phloroglucinol by taking 3,5-dichlorophenol as a starting material and taking strong base and a catalyst as auxiliary materials. Through the method, the phloroglucinol compound with high molar yield, high purity and low cost can be effectively synthesized.

Four esteryl-bridged energetic compounds have been derived from 2,2,2-trinitroethanol with polynitro benzoic acids and characterized via IR, multinuclear NMR spectroscopy, elemental analysis and differential scanning calorimetry (DSC). The structures of 2,2,2-trinitroethyl-2,4,6-trinitrobenzoate (5), bis(2,2,2-trinitroethyl)-4,6-dinitroisophthalate (6), bis(2,2,2-trinitroethyl)-2,5-dinitroterephthalate (7) and bis(2,2,2-trinitroethyl)-2,4,6-trinitroisophthalate (8) were further confirmed by X-ray diffraction studies, which show favorable densities (1.804-1.850 g cm-3). Interestingly, most of the polynitro esters decompose at temperatures over 180 °C (except for 6: 171.6 °C), which thus exhibit good thermal stability. In addition, performance calculations give detonation pressures and velocities for the ester derivatives in the range of 30.4-32.9 GPa and 8267-8559 m s-1, respectively. The esteryl-bridged compounds possess acceptable impact sensitivities (14-22 J), friction sensitivities (240-360 N), and electrostatic sensitivities (0.20-0.32 J). These values indicate that polynitro esters can be candidates as promising energetic materials.

Nucleofugalities of pentafluorobenzoate (PFB) and 2,4,6-trifluorobenzoate (TFB) leaving groups have been derived from the solvolysis rate constants of X,Y-substituted benzhydryl PFBs and TFBs measured in a series of aqueous solvents, by applying the LFER equation: log k = sf(Ef + Nf). The heterolysis rate constants of dianisylmethyl PFB and TFB, and those determined for 10 more dianisylmethyl benzoates in aqueous ethanol, constitute a set of reference benzoates whose experimental ΔG ? have been correlated with the ΔH? (calculated by PCM quantum-chemical method) of the model epoxy ring formation. Because of the excellent correlation (r = 0.997), the method for calculating the nucleofugalities of substituted benzoate LGs have been established, ultimately providing a method for determination of the SN1 reactivity for any benzoate in a given solvent. Using the ΔG? vs ΔH? correlation, and taking sf based on similarity, the nucleofugality parameters for about 70 benzoates have been determined in 90%, 80%, and 70% aqueous ethanol. The calculated intrinsic barriers for substituted benzoate leaving groups show that substrates producing more stabilized LGs proceed over lower intrinsic barriers. Substituents on the phenyl ring affect the solvolysis rate of benzhydryl benzoates by both field and inductive effects.

(Chemical Equation Presented) 5,7-Dinitroquinazoline-4-ones undergo nucleophilic displacement of a nitro group with N-, S-, and O-nucleophiles. In contrast to previously studied dinitro-substituted benzoannulated five- and seven-membered heterocycles (where a high degree of selectivity was observed), these quinazolines mostly yield mixtures of regioisomeric substitution products. At the same time, primary and secondary amines react selectively to afford 5-aminoquinazolones (peri-substitution). A similar effect is observed for some other polynitroaromatic compounds with adjacent nitro and carbonyl groups. This phenomenon is attributed to a stabilization of the intermediate peri-σ-complex by intramolecular hydrogen bond N+-H...O=C.

Substantial concentrations of phloroglucinol were synthesized by Pseudomonas fluorescens Pf-5 expressing the plasmid-localized phlACBDE gene cluster responsible for biosynthesis of 2,4-diacetylphloroglucinol. Expression in Escherichia coli of a single gene in this cluster, P. fluorescens Pf-5 phlD, led to extracellular accumulation of phloroglucinol. Purification of PhlD to homogeneity afforded an enzyme that catalyzed the conversion of malonyl-CoA into phloroglucinol with Km = 5.6 μM and kcat = 10 min-1. Acetylase and deacetylase activities were observed with the catalyzed interconversions of phloroglucinol, 2-acetylphloroglucinol, and 2,4-diacetylphloroglucinol when phlACB was expressed in E. coli. Beyond the mechanistic implications attendant with the identification of an enzyme that catalyzes the conversion of malonyl-CoA into phloroglucinol, PhlD provides the basis for environmentally benign syntheses of phloroglucinol and resorcinol from glucose. Copyright

Transformation processes of nitroaromatic compounds (NAC) lead to polar and highly hydrophilic metabolites. For the unequivocal identification of proposed metabolites reference substances are needed. Since most of them are not commercially available, their synthesis was done in our group. In many cases no satisfying synthesis schemes were found in the literature. In this communication, we therefore describe the preparation, structural elucidation and separation of 17 compounds. Many of the newly synthesized analytes were found in various water samples from a former ammunition plant.

A technique is described for the preparation of a wide variety of basic derivatives of linearly condensed tricyclic systems formed by two external benzene nuclei and a 7-membered central ring having 2 chalcogen atoms as hetero atoms. Derivatives of 11H-dibenzo(b,e)-1,4-dioxepin are obtained when the chalcogens are both oxygen atoms; derivatives of 11H-dibenzo(b,f)-1,4-dithiepin are obtained when the chalcogens are both sulfur atoms; derivatives of 6H-dibenz(b,e)-1,4-oxathiepin and 11H-dibenz(b,f)-1,4-oxathiepin are obtained with combinations of sulfur and oxygen atoms as chalcogens.