Method for producing dienes by hydrodimerization

A process for preparing a substituted or unsubstituted 1,7-diolefin, comprising:

• hydrodimerizing a non-cyclic olefin having at least two conjugated double bonds in a presence of a reducing agent and a catalyst,
• wherein the reducing agent comprises at least one selected from the group consisting of formic acid and a formate, the reducing agent is metered in during a course of the hydrodimerizing of the non-cyclic olefin such that a ratio of the non-cyclic olefin to the reducing agent is from 1:1 to 10:1, and the catalyst comprises a metal-carbene complex which has a metal of group 8 to 10 of the Periodic Table and at least one carbene ligand of the structure 2
• where:
• R1, R2=—(CH2)n—B
• B=mono- or polycyclic aryl group having 6 to 14 carbon atoms or mono- or polycyclic heterocycle having 5 to 14 carbon atoms and heteroatoms, where this heterocycle has 1 to 3 heteroatoms selected from the group consisting of N, O and S,
• n=0-4 and
• R3 and R4=substituents selected from the group consisting of hydrogen, alkyl, heteroaryl, aryl, —CN, —COOH, —COO-alkyl, —COO-aryl, —OCO-alkyl, OCO-aryl, —OCOO-alkyl, OCOO-aryl, —CHO, —CO-alkyl, —CO-aryl, —NH2, —NH(alkyl), —N(alkyl)2, NH(aryl), —N(aryl)2, —F, —Cl, —Br, —I, —OH, —CF3, —NO2, -ferrocenyl, —SO3H, and —PO3H2, where the alkyl groups have 1 to 12 carbon atoms and the aryl groups 5 to 14 carbon atoms, and the substituents of R3 and R4 may also be part of a bridging aliphatic or aromatic ring,
• and the substituents of R1 and R2 are the same or different and are substituted or unsubstituted, and the substituents of R3 and R4 are the same or different and are substituted or unsubstituted.