Synthesis, Structural Characterization And Combustion Catalytic Properties Of Ferrocene Ferrocene-based Ferrocene Ionic Compounds

Ferrocene and its derivatives are widely used in composite solid propellants due to their excellent combustion regulation functions.Up to now,the commercialized ferrocene-based burning rate catalysts can improve burning rates of hydroxyl-terminated polybutadiene(HTPB)-based propellants,but they are easy to migrate during prolonged storage and volatilize during curing process,so design and synthesis of new ferrocene-based burning rate catalysts with low-migration,low-volatility and high performance,have become a research hotspot in this area.In this thesis,novel ionic ferrocene compounds were designed and synthesized by using potassium ferricyanide as anion since it contains six cyanide anions in one molecule,mono(bis)ferrocenyl quaternary ammonium salts and imidazolium salts as cation sources.The detailed research contents are as follows:(1)With mono(bis)nuclear ferrocenyl quaternary ammonium iodides(bromides)and imidazolium iodides containing diverse alkyl chains in the ferrocenyl rings,and potassium ferricyanide as raw materials,28 designed novel ionic ferrocenyl derivatives were synthesized by ion exchange reaction.The synthetic processes were simple,the yields were high,and the products were easy to be separated and purified.The products were characterized by FT-IR,UV-Vis and EA,and compound 2 was additionally characterized by single crystal X-ray diffraction.(2)The thermal stability and volatility of the new compound were studied by TG technique.The results showed that at 5 ?/min they undergo rapid weight losses in the range of 152-163 ? with total weight-loss of 10-40%and followed by slow weight losses,indicating that they have good thermal stability,which is better than that of catocene.In addition,the TG curves of the new compounds at constant temperature of 70 ? under 24 hours showed that they exhibit very low weight loss.The TG curve of constant temperature at 70 ? from compounds 1-28 and Catocene(for comparison)shows that Catocene exhibits low volatility(4.4%loss after 24 hours)and weight loss of other compounds 1-28 Rates are lower than Catocene.Indicating that all compounds have excellent resistance to volatilization.(3)The electrochemical properties of the new compounds were studied by cyclic voltammetry.The results showed that the Epa of compounds 1-28 were higher by 100-200 mV than those of neutral molecules NBF,TBF and catocene under the same conditions,which indicated that the synthesized compounds cannot be easily oxidized and have better resistance to oxidation.The Epa of compounds 7,17 and 21 are less than 80 mV and Ipa/Ipc are between 1.0 and 1.5,so they are redox reversible systems;other compounds are irreversible redox systems since their AEp values are greater than 80 mV.(4)The effects of the prepared compounds on the thermal decomposition of the main components of the solid propellants,ammonium perchlorate(AP),1,3,5-trinitro-1,3,5-triazacyclohexane(RDX)and 1,2,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX),were evaluated by DSC.The results showed that the new compounds have significant effect on thermal decomposition of AP(the thermal decomposition peak temperature of AP shift to left dramatically and the released heat increase obviously).Among them,compound 11 has the most obviously effect on the thermal decomposition of AP with the released heat being-1449.47 J/g.The thermal decomposition peak temperature of RDX was advanced by the new compounds and the released heat of RDX increase with the new compound,except 11,as additives.The released heat of RDX+3%19 is the highest(-1197.30 J/g).Most of the new compounds(2,4-6,8,16,22 and 28)can advance the thermal decomposition peak temperature of HMX and enhance the released heat of HMX,indicating that these compounds have catalytic effects on the thermal decomposition of HMX.In summary,the synthesized 28 new ionic ferrocenyl compounds containing ferricyanide anions,have obvious combustion modification on the main components of solid propellants,and has the advantages of low-migration,high-thermal stability and strong antioxidant ability.The prepared ferrocene compounds can meet the basic requirements of ferrocene-based burning rate catalysts and can be as potential ferrocene-based burning rate modifiers.