scholarly journals Influence of Nitro Group Substitutes to the Stability and Energetic Properties of N-(2,4,6-trinitrophenyl)-1<i>H</i>- 1,2,4-triazol-3-amine

2017 ◽  
Vol 08 (02) ◽  
pp. 125-141 ◽  
Author(s):  
Jelena Tamuliene ◽  
Jonas Sarlauskas ◽  
Svajone Bekesiene
Keyword(s):  
Nitro Group ◽  
Energetic Properties ◽  
The Stability

scholarly journals Nitroaromatic Compounds, from Synthesis to Biodegradation

2010 ◽  
Vol 74 (2) ◽  
pp. 250-272 ◽  
Author(s):  
Kou-San Ju ◽  
Rebecca E. Parales
Keyword(s):  
Nitro Group ◽  
Aromatic Amines ◽  
Environmental Remediation ◽  
Oxidative Degradation ◽  
Nitroaromatic Compounds ◽  
Important Class ◽  
Industrial Chemicals ◽  
Evolutionary Origins ◽  
The Stability ◽  
The U.S

SUMMARY Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed.

Electrochemical reduction of 2,2'-dinitrodiphenylmethane and 2,2'-dinitrobenzophenone at mercury electrodes

1983 ◽  
Vol 48 (2) ◽  
pp. 364-378 ◽  
Author(s):  
Rolf Voigtländer ◽  
Jaromír Hlavatý ◽  
Jiří Volke ◽  
Viktor Bakos
Keyword(s):  
Nitro Group ◽  
Supporting Electrolyte ◽  
Standard Addition ◽  
The Other ◽  
Anodic Wave ◽  
Mercury Electrodes ◽  
Electron Reduction ◽  
The Stability ◽  
The One

The last two compounds in a 5-membered series of aromatic dinitro compounds are reduced in a completely different manner at mercury electrodes. 2,2'-Dinitrodiphenylmethane (I) - in which a conjugation of both symmetrical moieties is ruled out - is electrolytically reduced in an eight-electron step to a bishydroxylamine this being most stable between pH 4.5 and 5.0. In processing the catholyte increase in concentration of this product leads to its intermolecular disproportionation, resulting in the formation of dibenzo[b, e]-1,2-diazepine 5-oxide (IV) and 2,2'-diaminodiphenylmethane (III). 2,2'-Dinitrobenzophenone (II) reduces at more positive potentials. Its preparative electrolysis in acetonitrile (with 0.1M-N(n-C4H9)4PF6 as supporting electrolyte) the application of which was made necessary by the low solubility of II in ethanol, proceeding in an anomalous way. In the most positive cathodic wave a radical anion results, the following cathodic wave corresponds to a 6-electron reduction of the one nitro group to an amino group while the other nitro group splits off as the anion NO-2 (this later giving an anodic wave). Its formation has been proved by standard addition in polarography and by a qualitative analytical test. The product which results through this electrode process and a follow-up chemical reaction is acridone. This in turn, reduces in the third, most negative 4-electron wave to dihydroacridine. The comparison of all substances studied in this series reveals that their reducibility decreases with respect to the link X, viz. in the sequence CO > O > S and CH2 > NH. The electrolytical reduction on mercury cathodes occurs in a similar manner with analogues where X = O, S or CH2. Here, the main intermediate is the bis-hydroxylamine the stability of which predetermines the structure of final products. The other group comprises the substances with X = CO and NH. Here the main intermediate is the 2-nitro-2'-amino-diphenyl-X which is formed in a 6-electron process taking place at one of the nitro groups. The follow-up cyclization reaction leading to seven-membered heterocyclic rings located between two benzene nuclei only occurs with analogues of the type X = CH2, O and S. A partial reduction of dinitro compounds of this series has been observed with the analogue containing the NH link although that with X = CO has generally good preconditions for this mechanism.

Comparative theoretical studies of dinitromethyl- or trinitromethyl-modified derivatives of CL-20

2013 ◽  
Vol 91 (12) ◽  
pp. 1243-1251 ◽  
Author(s):  
Yong Pan ◽  
Weihua Zhu ◽  
Heming Xiao
Keyword(s):  
Thermal Stability ◽  
Density Functional ◽  
Parent Compound ◽  
Initial Step ◽  
Impact Sensitivity ◽  
Detonation Properties ◽  
Energetic Properties ◽  
The Stability ◽  
The Impact ◽  
Trinitromethyl Group

The heats of formation (HOFs), energetic properties, strain energies, thermal stability, and impact sensitivity for a series of trinitromethyl- or dinitromethyl-modified CL-20 derivatives were studied by using density functional theory. It is found that the trinitromethyl group is an effective structural unit for improving the gas-phase HOFs and energetic properties of the derivatives. However, incorporating the dinitromethyl group into the parent compound is not favorable for increasing its HOFs and detonation properties. The effects of the dinitromethyl or trinitromethyl groups on the stability of the parent compound are discussed. The studies on strain energies show that the introduction of the trinitromethyl group intensifies the strain of the cage skeleton for the title compounds, whereas for the dinitromethyl groups, the case is quite the contrary. An analysis of the bond dissociation energies for several relatively weak bonds suggests that the substitution of the dinitromethyl or trinitromethyl group decreases the thermal stability of the derivatives. The C−NO2 bond in the dinitromethyl or trinitromethyl group is the weakest one and the homolysis of the C−NO2 bond may be the initial step in thermal decomposition. In addition, according to the calculated free space per molecule, the introduction of the dinitromethyl or trinitromethyl group increases the impact sensitivities of the derivatives. Considering the detonation performance, thermal stability, and impact sensitivity, six compounds can be regarded as the target high-energetic compounds.

scholarly journals Theoretical screening of bistriazole-derived energetic salts with high energetic properties and low sensitivity

RSC Advances ◽  
2019 ◽  
Vol 9 (45) ◽  
pp. 26442-26449 ◽  
Author(s):  
Xiao-Hong Li ◽  
Cong Zhang ◽  
Xue-Hai Ju
Keyword(s):  
Nitro Group ◽  
Energetic Properties ◽  
Energetic Salts ◽  
Low Sensitivity ◽  
Bridging Groups ◽  
Trinitromethyl Group

We designed four series of energetic anions by replacing nitro group (NO2) with trinitromethyl group (C(NO2)3) or by inserting N-bridging groups (–NH–, –NH–NH–, –NN–, –NN(O)–) into the bistriazole frameworks.

The Configuration of Organic Carbanions

1976 ◽  
Vol 31 (5) ◽  
pp. 494-497 ◽  
Author(s):  
Muthana Shanshal
Keyword(s):  
Nitro Group ◽  
Small Ring ◽  
Pyramidal Configuration ◽  
The Stability

Abstract The configurations of organic carbanions are studied using the MINDO/1 and MINDO/2 methods. It is found that the stability of the pyramidal configuration increases on going to small ring cyclic carbanions. Conjugation to an olefinic group decreases the inversion barriers of pyramidal carbanions but does not lead to their planarization. Conjugation to a nitro group, however, causes the planarization of the carbanions. It is found that the monosolvation of methylcarbanion increases its planarization energy.

scholarly journals Solvent Effect on the Stability and Reverse Substituent Effect in Nitropurine Tautomers

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1223
Author(s):  
Anna Jezuita ◽  
Paweł A. Wieczorkiewicz ◽  
Halina Szatylowicz ◽  
Tadeusz M. Krygowski
Keyword(s):  
Solvent Effect ◽  
Nitro Group ◽  
Density Functional ◽  
Polarizable Continuum Model ◽  
Proximity Effects ◽  
Intramolecular Interactions ◽  
Solvation Energies ◽  
Wide Range ◽  
The Stability ◽  
Reverse Substituent Effect

The solvent effect on the stability and electron-accepting properties (EA) of the nitro group attached to the C2, C6, or C8 position of nitropurine NH tautomers is investigated. For this purpose, the density functional theory (DFT) and the polarizable continuum model (PCM) of solvation in a wide range of solvents (1 < ε < 109) are used. We show that the EA properties of the NO2 group, described by the charge of the substituent active region (cSAR) model, are linearly dependent on the reciprocal of the solvent dielectric constant; in all cases, solvation enhances the EA properties of this group. Furthermore, the sensitivity of EA properties of the nitro group to the solvent effect depends on the proximity effects. It has been shown that the proximity of two endocyclic N atoms (two repulsive interactions) results in higher sensitivity than the asymmetric proximity of the endocyclic N atom and NH group (one repulsive and one attractive interaction). To explain this phenomenon, the geometry of the nitro group in coplanar form and after forcing its rotation around the CN bond is discussed. Relative stabilities of nitropurine tautomers in different solvents are also presented. Differences in the stabilities and solvation energies are explained by aromaticity, electronic structure, and intramolecular interactions of the nitropurine tautomers.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Uniformity of Magnification from Different Electron Microscopes

1967 ◽  
Vol 25 ◽  
pp. 32-33
Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison
Keyword(s):  
Diffraction Grating ◽  
The Other ◽  
Carbon Replica ◽  
Electron Microscopes ◽  
The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

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