Preparation of butenyl ethers

A process for preparing butenyl ethers of the formula I

• CH3—CH═CH—CH2—OR I
• by reacting butadiene or butadiene-containing hydrocarbon streams with alcohols of the formula II
• ROH II
• at elevated temperature and superatmospheric pressure in the presence of transition metal complexes containing ligands of compounds of elements of group V of the Periodic Table of the Elements to form an isomer mixture of butenyl ethers of the formula I and butenyl ethers of the formula III
• CH2═CH—CH(OR)—CH3 III
• and, if desired, isomerizing the butenyl ethers of the formula III to butenyl ethers of the formula I, where in each case R is an alkyl or alkenyl group having from 1 to 20 carbon atoms, an aryl group having from 6 to 10 carbon atoms or an aralkyl group having from 7 to 11 carbon atoms and the radicals R may be substituted by hydroxy or alkoxy groups, wherein the catalyst used is a complex of a transition metal of group VIII of the Periodic Table of the Elements with ligands of the formula IV
• where M is an iron, cobalt, nickel or ruthenium atom, X is a bridge in the form of a substituted or unsubstituted methylene group or an alkyl-substituted silylene group, where n is from 0 to 3, R1 to R4 are, independently of one another, also independently of one another in the two cyclopentadienyl radicals, hydrogen or alkyl, cycloalkyl, aryl or aralkyl radicals having up to 40 carbon atoms or can be part of an isocyclic or heterocyclic ring system, where the two cyclopentadienyl radicals can also be bridged to one another via the respective radicals R1 to R4, Y is nitrogen, arsenic, antimony or phosphorus and the radicals R5 and R6 are, independently of one another, also independently of one another in the two molecules of the sandwich complex, hydrogen or alkyl, cycloalkyl, aryl or aralkyl radicals having up to 24 carbon atoms.