Ferrocenyl Ionic Compounds Containing [Fe(CN)6]3- Anions: Synthesis, Characterization, and Catalytic Effects during Combustion

Twenty-eight novel ferrocenyl ionic compounds, composed of mononuclear 1-ferrocenylmethylalkyldimethylammoniums, 1-ferrocenylmethyl-3-alkylimidazoliums, or their dinuclear analogs and [Fe(CN)(6)](3-) anion, were designed and synthesized to tackle significant volatility and migration tendency of ferrocene-based burning rate catalysts (BRCs) used currently in the composite solid propellants. The new compounds were characterized by UV/Vis, FT-IR, and elementary analysis. The crystal structures of compounds 2 center dot 5H(2)O and 3 center dot CH2Cl2 center dot 4H(2)O verified the successful preparation of the desired ionic compounds. The TG tests at 70 degrees C for 24 h revealed that the new compounds exhibit lower volatility than catocene. The cyclic-voltammetry results suggested that new compounds are quasi-reversible or irreversible redox systems. TheTG/DSC analyses exhibited that the compounds are of highly thermal stability. Their catalytic effects on the thermal degradation of ammonium perchlorate (AP), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), and 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) were investigated. The results showed that most of the compounds exert great effects on the thermal degradation of AP and RDX during combustion. 11 and 2 are comparable to catocene in the thermal decomposition of AP and RDX, respectively, and can therefore be used as alternatives of catocene in a composite solid propellant. Some new compounds are unexpectedly active in promoting the thermal disintegration of HMX.