Abstract: The invention provides the use of an organic compound selected from a bicyclic monoterpene, substituted bicyclic monoterpene, adamantane, propylene carbonate and mixtures thereof, to improve the solubilization of a solid, fuel-soluble iron compound in a fuel composition or in a precursor liquid to be added to fuel composition.

Abstract: The invention provides the use of an organic compound selected from a bicyclic monoterpene, substituted bicyclic monoterpene, adamantane, propylene carbonate and mixtures thereof, to improve the solubilisation of a solid, fuel-soluble iron compound in a fuel composition or in a precursor liquid to be added to fuel composition.

Abstract: Ferrocene dicarboxylic acid diesters have the general formula (I), in which X stands for an oligoethylene glycol radical with 2 to 20 ethoxyl units and/or an &agr;,&ohgr;-alkyldiol radical with 2 to 18 C atoms. Also disclosed are processes for preparing the same, their use, solid composite propellants containing the disclosed ferrocene dicarboxylic acid diesters and processes for preparing the same.

Abstract: Ferrocene compounds are produced from related intermediates, wherein the ferrocene compounds are represented by the general formula (I): ##STR1## wherein Z is one of the groups --CH.sub.2 --Y, --CO--(CH.sub.2).sub.n --CO--X or --CO--X, in which n is 1 to 6; X is an (oligo-)alkylene glycol residue with 1 to 10 alkoxy units or an alkanediol residue with 2 to 18 carbon atoms, and Y is X or OH, andR is an alkyl group with 2 to 18 carbon atoms, an aralkyl group with 7 to 20 carbon atoms, or H, when Y.noteq.OH.The related intermediates differ from the ferrocene compound in that Z is replaced by Z' which is --COOH or --CO--(CH.sub.2).sub.n --COOH. The ferrocene compounds of formula (I) are especially suitable as combustion moderators for solid fuels.