Method for separating 1-butene from C

1. A process for removing 1-butene from a C 4 hydrocarbon mixture comprising isobutene and 1-butene by hydroformylation, said process comprising

hydroformulating a hydroformulation mixture comprising said C 4 hydrocarbon mixture and a catalyst system comprising one or more of the transition metals of groups 8 to 10, and a bisphosphite ligand of the following formula I

where X is a divalent substituted or unsubstituted bisalkylene or bisarylene radical which comprises one or more heteroatom(s), Y is a divalent substituted or unsubstituted bisarylene radical or a divalent substituted or unsubstituted bisalkylene radical which comprises one or more heteroatom(s), Z is oxygen or NR 9 , and R 1 , R 2 , R 3 , R 4 are identical or different, substituted or unsubstituted, connected, unconnected or fused aryl or heteroaryl radicals, and R 9 is hydrogen or substituted or unsubstituted alkyl or aryl radical which comprises one or more heteroatom(s), the bisphosphite ligand of the above-specified formula I being in an excess of a molar ratio of 100:1 to 1:1 relative to the transition metal, and less than 5% of the isobutene present being converted at a 1-butene conversion of more than 95%.

2. The process according to claim 1 , wherein the concentration of the transition metal in the hydroformylation mixture is 1 ppm by mass up to 1000 ppm by mass based on the total weight of the reaction mixture.

3. The process according to claim 1 , wherein the transition metal is rhodium and the molar ratio of bisphosphite to rhodium is in the range from 90:1 to 1:1.

4. The process according to claim 1 , wherein the transition metal is rhodium and the molar ratio of bisphosphite to rhodium is in the range from 10:1 to 2:1.

5. The process according to claim 1 , wherein less than 5% of the isobutene present is converted at a 1-butene conversion of more than 99%.

6. The process according to claim 1 , wherein 1-butene is hydroformylated with an n-/iso selectivity of more than 97%.

7. The process according to claim 1 , wherein 1-butene in the feed hydrocarbon mixture is removed to an extent of more than 99% from the C 4 hydrocarbon mixture by hydroformylation at a temperature of from 40 to 120° C.

8. The process according to claim 1 , wherein 1-butene in the feed hydrocarbon mixture is removed to an extent of more than 99% from the C 4 hydrocarbon mixture by hydroformylation at a temperature of from 70 to 95° C.

9. The process according to claim 1 , wherein the hydroformylation is carried out within a pressure range of from 0.5 to 30 MPa.

10. The process according to claim 1 , wherein the hydroformylation is carried out within a pressure range of from 1.0 to 6.4 MPa.

11. The process according to claim 1 , wherein the process is performed continuously.

12. The process according to claim 1 , wherein the C 4 hydrocarbon mixture comprises 2-butene.

13. The process according to claim 1 , wherein the reaction mixture is separated into C 5 aldehyde, isobutene, a high boiler fraction comprising the dissolved catalyst system and C 4 hydrocarbon.

14. The process according to claim 13 , wherein the further C 4 hydrocarbon is subjected to an isomerizing hydroformylation to give valeraldehyde.

15. The process according to claim 14 , wherein the C 5 aldehydes obtained from selective hydroformylation and isomerizing hydroformylation are combined.

16. The process according to claim 13 , wherein the C 5 aldehyde removed is subjected to an aldol condensation, dehydration and subsequent hydrogenation to form 2-propylheptanol.

17. The process of claim 1 , wherein the catalyst system comprises rhodium.

18. The process of claim 1 , wherein the bisphosphite ligand is selected from the group consisting of the following formulae Ia, Ib and Ic:

19. The process of claim 18 , wherein the bisphosphite ligand has formula Ia, and the transition metal is rhodium.