Trinitromethyl Groups Research Articles

Fluorine-Containing Functional Group-Based Energetic Materials.

Molecules featuring fluorine-containing functional groups exhibit outstanding properties with high density, low sensitivity, excellent thermal stability, and good energetic performance due to the strong electron-withdrawing ability and high density of fluorine. Hence, they play a pivotal role in the field of energetic materials. In light of current theoretical and experimental reports, this review systematically focuses on three types of energetic materials possessing fluorine-containing functional groups F- and NF2 - substituted trinitromethyl groups (C(NO2 )2 F, C(NO2 )2 NF2 ), trifluoromethyl group (CF3 ), and difluoroamino and pentafluorosulfone groups (NF2 , SF5 ) and investigates the synthetic methods, physicochemical parameters, and energetic properties of each. The incorporation of fluorine-containing functional moieties is critical for the development of novel high energy density materials, and is rapidly being adopted in the design of energetic materials.

Theoretical investigation of energetic performance and impact sensitivities of nitro and trinitromethyl substituted ozonides of ethylene and cyclopentene

A series of novel energetic compounds were designed by introducing groups such as NO2, and C(NO2)3 to the ethylene ozonide (trioxolane) and cyclopentene ozonide (6,7,8-trioxabicyclo[3,2,1]octane) skeletons and their detonation properties and impact sensitivity were investigated using DFT - B3LYP method with aug-cc-pVDZ as basis set. We could design compounds with densities >2 g cm−3. Most of the compounds exhibit high heat of formation and excellent detonation properties, predominant over traditional energetic compounds. The impact sensitivities of many compounds satisfy criterion of energetic compounds. The compounds containing trinitromethyl (TNM) groups are found to have excellent detonation performance. Also, in trioxabicyclo[3,2,1]octane derivatives, compounds containing TNM group on one of the carbon atoms which was unsaturated in the parent cyclopentene were found to be more stable, addition of NO2 group on the other carbon enhances the properties as well.

Energy capabilities of composites solid propellant upon replacement of trinitromethyl groups in the oxidizer by fluorodinitromethyl groups

The energy capabilities of solid composite propellants in which the trinitromethyl groups of the oxidizer are replaced by fluorodinitromethyl groups are examined. This replacement is shown to lead to a significant decrease in the enthalpy of formation and, consequently, the specific impulse, but at the same time slightly reduces the sensitivity and substantially increases the thermal stability. The use of such oxidizers can be useful for creating formulations with increased requirements for thermal stability.

Synthesis, characterisation and crystal structures of two bi-oxadiazole derivatives featuring the trifluoromethyl group.

The synthesis, characterisation, and crystal structure determination of the closely related compounds 3,3'-bi-(5-trifluoromethyl-1,2,4-oxadiazole) and 5,5'-bi-(2-trifluoromethyl-1,3,4-oxadiazole) are reported. These two compounds are known for their bioactivity; however, in this study they serve as model compounds to evaluate the suitability of the heterocyclic oxadiazole ring system for energetic materials when the fluorine atoms in the exocyclic CF3 groups are substituted successively by nitro groups. Quantum chemical calculations for the bi-1,3,4-oxadiazole derivatives with difluoronitromethyl, fluorodinitromethyl, and trinitromethyl groups have been carried out and predict promising energetic performances for both explosive and propulsive applications.

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

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.

Paradigms and paradoxes: a comparison of the enthalpies of formation of trinitromethyl and trimethylmethyl (t-butyl) containing species

In a further attempt to understand the interplay of structure and energy of compounds containing nitro groups, the enthalpies of formation of corresponding species with trinitromethyl and trimethylmethyl (t-butyl) groups are compared.

Condensed tetrazolo-1,3,5-triazines. 4. Synthesis of salts of 5-aminotetrazolo[1,5-a]-1,3,5-triazin-7-one

2-Amino-4-azido-1,3,5-triazin-6(1H)-ones were synthesized by successive substitution of the trinitromethyl groups in 2-amino-4,6-bis(trinitromethyl)-1,3,5-triazines under the influence of azide and nitrite ions. Interaction of 2-amino-4-azido-1,3,5-triazin-6(1H)-ones with bases led to the azido-tetrazole tautomeric conversion give salts of 5-aminotetrazolo[1,5-a]-1,3,5-triazin-7-one.

Nucleophilic Substitution Reactions of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine. 3. Reaction of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine with Azides and Hydrazine

As a result of nucleophilic substitution of the trinitromethyl groups in 2,4,6-tris(trinitromethyl)-1,3,5-triazine, the corresponding monoazido and diazido derivatives have been synthesized. The reaction of the starting triazine with hydrazine acetate in the presence of trifluoroacetic acid leads to 1-acetyl-2,2-bis[4,6-bis(trinitromethyl)-1,3,5-triazin-2-yl]hydrazine.

Nucleophilic substitution reactions of 2,4,6-tris(trinitromethyl)-1,3,5-triazine. 1. Interaction of 2,4,6-tris(trinitromethyl)-1,3,5-triazine with alcohols, diols, ammonia, and secondary amines

A study has been made of nucleophilic substitution reactions of 2,4,6-tris(trinitromethyl)-1,3,5-triazine with certain nucleophiles. The possibility of replacing one, two, or three trinitromethyl groups in this compound has been demonstrated.

Tetranitroquinodimethane (Tnq)—Electron-Deficient Prototype for a New Series of Organic Solid State Materials

ABSTRACTRecently we have synthesized several new aryl compounds substituted with two or more trinitromethyl groups. Vacuum pyrolysis of one of these—±,±,±,±’,±’,±’-hexanitro-p-xylene (p-HNX)—gave the title compound via 1,6-elimination of N2O4. Structural assignment of TNQ is based on spectral evidence (UV, 1H NMR and mass spectrometry) and conversion to the known l,4-bis(bromodinitromethyl)benzene. Evidence for the formation of the TNQ radical anion has been obtained.

Thermal stability/structure relations of some polynitroaliphatic explosives

Thermal stability/chemical structure relations were investigated for different classes of energetic compounds containing trinitromethyl, fluorodinitromethyl, and gem-dinitroethyl groups. In the vacuum thermal stability test used to determine the thermal characteristics of the materials, samples are heated to elevated temperatures under vacuum and the amounts of gaseous decomposition products are measured. The following results were obtained: (a) The thermal stabilities of energetic compounds containing trinitromethyl groups are lower than those of materials containing fluorodinitromethyl or gem-dinitroethyl groups if these groups are in a sterically unhindered environment. The trinitromethyl compounds generally have acceptable stability up to 150°C when solid and 100°C when molten. The fluorodinitromethyl compounds have acceptable stability at 180°C or higher when solid, and up to 165°C when liquid. Fluorodinitromethyl and dinitroethyl compounds have thermal decomposition rates that are 1 80 -to 1 200 of those of trinitromethyl compounds. (b) Energetic materials containing C(NO 2) 3-, FC(NO 2) 2-, or CH 3C(NO 2) 2- groups in an environment which is sterically hindered by neighboring bulky substituents all have substantially decreased thermal stability compared to unhindered materials. The rationale suggested is that intramolecular rotational modes serve as an enthalpy sink, and that “freezing out” these modes causes more energy to be distributed into the vibrational modes which lead eventually to bond homolysis.

Synthesis and properties of ?-C-nitrohydrazones. 3. Reaction of salts of asymmetric hydrazines with compounds containing trinitromethyl groups and polynitromethanes

A method is proposed for the synthesis of α-C-nitrohydrazones by the reaction of salts of 1,1-disubstituted hydrazines with polynitro compounds.