Evaluation of Mono and Bimetallic Ferrocene-Based 1,2,3-Triazolyl Compounds as Burning Rate Catalysts for Solid Rocket Motor

We reported mono and bimetallic ferrocene-based 1,2,3-triazolyl compounds as potential burning rate catalysts in their neutral and ionic forms. All complexes reported here were characterized using 1H and 13C NMR, elemental analysis, and Mössbauer spectroscopy, which was performed for neutral and oxide compounds. The complexes present quasireversible redox potentials with higher oxidative ability than ferrocene and catocene under the same conditions. The complexes were tested as catalysts on the thermal decomposition of ammonium perchlorate (AP) and examined by a differential scanning calorimetry technique to gain further knowledge about their catalytic behavior. Compound 1 causes a decrease of the high-temperature decomposition (HTD) of AP positively, decreasing the decomposition temperature of AP to 345 °C and consequently increasing the energy release to 1939 J·g-1. We took the residues from the pans after testing from the DSC to elucidate the underlying reaction pathways. We obtained the size of the nanostructures formed after thermal decomposition of AP determined by the TEM technique. The diameter and size distribution of iron oxide nanoparticles formed depend on the alkyl sidechain of the triazolium ring, which induces the formation of nanoparticles with a double diameter and size distribution compared to their neutral analogues, suggesting that the possible intermediate for the mechanism degradation of AP by ferrocene derivatives is nanoscale Fe2O3 or similar oxides.

Heterobimetallic Catalysts for the Thermal Decomposition of Ammonium Perchlorate: Efficient Burning Rate Catalysts for Solid Rocket Motors and Missiles

We show the synthesis and characterization of four heterobimetallic compounds derived from s-indacene of general formula [{(CO)₃Mn}-s-Ic-{MCp*}]^q with M = Fe, Co, Ni, and Ru; q = 0, 1+. The complexes reported here were characterized by ¹H and ¹³C NMR, elemental analysis and FT-IR. Additionally, the X-ray crystal structure of [(CO)₃Mn-s-Ic-FeCp*] (1) and Mössbauer spectra are reported. The heterobimetallic compounds exhibit higher quasireversible redox potentials compared with ferrocene and catocene under the same reaction conditions. The complexes were tested as catalysts on the thermal decomposition of ammonium perchlorate examined by a differential scanning calorimetry technique to study their catalytic behavior. Compound (1) causes a decrease of ammonium perchlorate's decomposition temperature to 315 °C, consequently increasing the heat release by 138 J·g^-1. Conversely, [{(CO)₃Mn}-s-Ic'-{CoCp*}] (2) presents a higher heat release (2462 J·g^-1), comparable to catocene.

Anti-migration and burning rate catalytic performances of novel ferrocene-based porphyrins and their transition-metal complexes

Novel ferrocene-based porphyrins and metal porphyrins exhibited non-migratory ability and excellent burning rate catalytic performance for composite solid propellants.

Synthesis of ethylene diamine-based ferrocene terminated dendrimers and their application as burning rate catalysts

Ferrocene-based derivatives are widely used as ferrocene-based burning rate catalysts (BRCs) for ammonium perchlorate (AP)-based propellant. However, in long storage, small ferrocene-based derivatives migrate to the surface of the propellant, which results in changes in the designed burning parameters and finally causes unstable combustion. To retard the migration of ferrocene-based BRCs in the propellant and to increase the combustion of the solid propellant, zero to third generation ethylene diamine-based ferrocene terminated dendrimers (0G, 1G, 2G and 3G) were synthesized. The synthesis of these dendrimers was confirmed by ¹H NMR and FT-IR spectroscopy. The electrochemical behavior of 0G, 1G, 2G and 3G was investigated by cyclic voltammetry (CV) and the burning rate catalytic activity of 0G, 1G, 2G and 3G on thermal disintegration of AP was examined by thermogravimetry (TG) and differential thermogravimetry (DTG) techniques. Anti-migration studies show that 1G, 2G and 3G exhibit improved anti-migration behavior in the AP-based propellant.

Pentagonal five-center four-electron π bond in ternary B3N2H5 cluster: an extension of the concept of three-center four-electron ω bond

Ternary B₃N₂H₅ (C_2v, ¹A₁) cluster has a heteroatomic B₃N₂ ring, with 4π electrons in a robust bonding/nonbonding combination, which is proposed as a five-center four-electron o-bond.

Synthesis of ferrocene-based saccharides and their anti-migration and burning rate catalytic properties

In the search for ferrocene-based burning rate catalysts (BRCs) with good burning rate catalytic properties and low migration, we synthesized four ferrocene-based saccharides (S-Fcs).

Effects of metal organic framework Fe-BTC on the thermal decomposition of ammonium perchlorate

Fe-BTC effectively enhances the thermal decomposition of AP and improves the combustion properties of BAMO–THF propellant with AP as the oxidizer.

Planar B3S2H3−and B3S2H3clusters with a five-membered B3S2ring: boron–sulfur hydride analogues of cyclopentadiene

Boron–sulfur hydride clusters,C_2vB₃S₂H₃⁻and B₃S₂H₃, possess a five-membered B₃S₂ring as the core, which is analogous to cyclopentadiene in terms of π bonding.