Patent ID: 8575056

Claim:
A method of preparing a catalytic composition comprising the following stages: a) contacting, optionally in the presence of a solvent, at least one iron compound (compound A) with at least one compound B resulting from the condensation of a compound X with a compound Y whose general formulas are given below: R 1 to R 11 , identical or different, representing alkyl groups, saturated or not, cycloalkyl or aromatic, aryl or aralkyl, optionally substituted, hydrogen, a halogenide, alkoxy, aryloxy or amino groups, b) optionally isolating at least one product resulting from the reaction of A with B, c) oxidizing with an oxidizing agent of the resultant mixture of compounds A and B, or of the product optionally isolated in stage b), d) optionally isolating at least one product resulting from stage c), e) adding an activating agent (compound C), and f) optionally adding a solvent (compound D).