GB737109A - Improvements in and relating to the production of dicyclopentadienyl iron and substitution products thereof - Google Patents

Abstract

Compounds of formula R2Fe, where R is a cyclopentadienyl or substituted cyclopentadienyl group may be prepared by mixing an anhydrous ferrous halide with a cyclopentadiene or substituted cyclopentadiene compound of formula RMgX or RY, where RY, where X is chlorine, bromine or iodine and Y is an alkali metal, in an inert solvent and heating if necessary. Specified substituted cyclopentadienes include 2-methyl-4-ethyl-, 1-methyl-3-ethyl-, 1-methyl-3-isopropyl-, 1-isopropyl-3-methyl-, 1,2,3,4-tetraphenyl-, 1,2,3-triphenyl-, 1-methyl-2,3,5-triphenyl-, 1,4-dimethyl-2,3,5-triphenyl, 1,4-diphenyl-cyclopentadienes, and the 5-alkyl-cyclopentadienes obtained by reduction of the fulvenes. The cyclopentadienyl magnesium halides may be prepared by reacting the appropriate cyclopentadiene with an alkyl magnesium halide, preferably a short chain primary alkyl magnesium bromide. Suitable solvents include diethyl ether, dipropyl ether, ethyl propyl ether, benzene, toluene, xylene, hexane, heptane, octane, gasoline, kerosine and volatile petroleum hydrocarbon mixtures. The reaction with a Grignard reagent may be carried out between 30 DEG and 50 DEG C., and that with an alkali metal cyclopentadienide between 50 DEG and 110 DEG C. In an example ethyl magnesium bromide is prepared in dry ether and converted to cyclopentadienyl magnesium bromide by addition of freshly distilled cyclopentadiene. Anhydrous ferrous chloride is then added to the cooled mixture. Inorganic salts are removed from the ether solution by extraction with water, and the solution is dried over anhydrous sodium sulphate, concentrated and the dicyclopentadienyl iron allowed to crystallize. It may be recrystallized from industrial methylated spirits. Example III describes the method using cyclopentadienyl potassium. Specification 737,092, [Group III], is referred to.