Recent progress on ferrocene-based burning rate catalysts for propellant applications

Organocatalytic Enantioselective Nucleophilic Substitution of Furfurals with Alcohols via a Remote Chiral Control

We describe herein the direct organocatalytic asymmetric nucleophilic substitution reaction of 2-benzylfurfurals with benzyl alcohols and allylic alcohol in the absence of any metal catalysts and ligands. A series of γ-regioselective products were obtained in high yields and up to 99% enantiomeric excess.

Mechanistic Insights into the Thermal Decomposition of Ammonium Perchlorate: The Role of Amino-Functionalized Magnetic Nanoparticles

This work reports the characterization and application of two promising nanocatalysts for the thermal decomposition of ammonium perchlorate (AP). To obtain these composite materials, magnetite nanoparticles (Fe₃O₄ NP_s) were functionalized with two different amine derivative groups, tertiary amine (Fe₃O₄ NP_s-A1) and quaternary amine. X-ray photoelectron spectroscopy and differential scanning calorimetry provided mechanistic insights into the thermal decomposition of AP. Furthermore, tertiary and quaternary amine groups play a critical role, where the presence of an extra proton could favor an electron-proton transfer as the rate-determining step. Moreover, Fe₃O₄ NP_s-A1 causes a diminution of the high-temperature decomposition of AP positively to 335 °C, increasing the energy release by 278 J g^-1 and consequently affording the lowest activation energy (102 kJ mol^-1), indicating a low degree of thermal stability, and accelerating the thermal decomposition of AP.

Forever young: the first seventy years of ferrocene

The discovery of ferrocene, [Fe(η5-C5H5)2], seventy years ago has significantly influenced chemical research and provided a key impetus for establishing and rapidly expanding organometallic chemistry, which has continued at a...

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.

Hollow polymer nanocapsules with a ferrocenyl copolymer shell

Hollow polymer nanocapsules consisting of ferrocenyl shell have been developed by crosslinking the polymer chains grafted over silica nanoparticles synthesized via one pot surface-initiated RAFT polymerization.

Nanochromates MCr2O4 (M = Co, Ni, Cu, Zn): Preparation, Characterization, and Catalytic Activity on the Thermal Decomposition of Fine AP and CL-20

The chromate nanoparticles such as CoCr₂O₄, NiCr₂O₄, CuCr₂O₄, and ZnCr₂O₄ were prepared by a modified sol-gel method. The structural and morphological properties of the chromate nanoparticles were characterized by X-ray diffraction (XRD) and a scanning electron microscope (SEM). The catalytic effects of chromates on the thermal decomposition of fine ammonium perchlorate (FAP) and hexanitrohexaazaisowurtzitane (CL-20) were studied by the TG-DTG measurements. Results show that the addition of CoCr₂O₄, NiCr₂O₄, CuCr₂O₄, and ZnCr₂O₄ nanoparticles makes the activation energies for the thermal decomposition of FAP decrease by 93.9, 94.0, 83.1, and 67.0 kJ·mol^-1, and the thermal decomposition temperatures decrease by 45.0, 24.9, 57.7, and 38.8 K respectively. On the other hand, a similar trend exists in the case of the thermal decomposition of CL-20. Therefore, the addition of nanochromates shows high catalytic efficiency on the thermal decomposition of both FAP and CL-20 components, which would be beneficial to promote the burning rate of propellants containing FAP and CL-20 components.

Porous Cr2O3 bead with a 3D continuous pore architecture: synthesis and its catalytic performance for decomposition of ammonium perchlorate

Mesoporous/macroporous Cr₂O₃ beads with 3D continuous pore structure exhibit improved thermal decomposition of ammonium perchlorate compared with Cr₂O₃ crystals.