Process for producing at least 1-hexene and octene from ethene comprising the steps of: a) providing a feedstock mixture comprising ethene; b) subjecting the ethene to a first oligomerization to obtain a first oligomerizate which comprises olefins having less than six carbon atoms, at least the C 6 olefins 1-hexene, 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene and olefins having more than six carbon atoms, c) distillative workup of the first oligomerizate to obtain a C 6 fraction which comprises at least 1-hexene, 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene, d) subjecting the C 6 fraction to an etherification by addition of an alcohol in the presence of a heterogeneous catalyst to obtain a first reaction mixture comprising at least 1-hexene and 3-methyl-3-methoxypentane; e) distillative workup of the first reaction mixture to obtain a first target fraction comprising 1-hexene and an ether fraction at least comprising 3-methyl-3-methoxypentane; wherein the improvement consists in: f) the ether fraction is subjected to a cleavage reaction to obtain a cleavage product which comprises at least 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene and the alcohol; g) the alcohol is removed from the cleavage product by distillation and reused in the etherification; h) a first intermediate comprising at least 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene is removed from the cleavage product by distillation; i) the first intermediate is reacted with ethene to obtain a second reaction mixture which comprises olefins having at least eight carbon atoms; k) a second target fraction comprising octene is obtained from the second reaction mixture by distillation, wherein a solid body comprising at least two components is employed as a heterogeneous catalyst in the first oligomerization and/or in the second oligomerization, wherein the first component comprises at least one element selected from Ni, Fe, Ti which is present in metallic and/or oxidic and/or hydridic form and wherein the second component comprises at least one metal oxide selected from Al 2 O 3, SiO 2, TiO 2, ZrO 2. a) providing a feedstock mixture comprising ethene; b) subjecting the ethene to a first oligomerization to obtain a first oligomerizate which comprises olefins having less than six carbon atoms, at least the C 6 olefins 1-hexene, 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene and olefins having more than six carbon atoms, c) distillative workup of the first oligomerizate to obtain a C 6 fraction which comprises at least 1-hexene, 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene, d) subjecting the C 6 fraction to an etherification by addition of an alcohol in the presence of a heterogeneous catalyst to obtain a first reaction mixture comprising at least 1-hexene and 3-methyl-3-methoxypentane; e) distillative workup of the first reaction mixture to obtain a first target fraction comprising 1-hexene and an ether fraction at least comprising 3-methyl-3-methoxypentane; f) the ether fraction is subjected to a cleavage reaction to obtain a cleavage product which comprises at least 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene and the alcohol; g) the alcohol is removed from the cleavage product by distillation and reused in the etherification; h) a first intermediate comprising at least 3-methyl-cis-2-pentene, 3-methyl-trans-2-pentene is removed from the cleavage product by distillation; i) the first intermediate is reacted with ethene to obtain a second reaction mixture which comprises olefins having at least eight carbon atoms; k) a second target fraction comprising octene is obtained from the second reaction mixture by distillation,