Method for the hydroformylation of olefins

摘要

The present invention relates to a process for preparing hydroformylation products of olefins having at least four carbon atoms, in which a high proportion of both the linear Ci-olefins having a terminal double bond comprised in the olefin-comprising feed used and of the linear Ci-olefins having an internal double bond is converted into hydroformylation products. Furthermore, the invention relates to a process for preparing 2-propylheptanol which comprises such a hydroformylation process.

主权项

1. A process for preparing 2-propylheptanol which comprises
i) subjecting a mixture of 1-butene and 2-butene or a C4-hydrocarbon mixture comprising 1-butene and 2-butene to a hydroformylation comprising subjecting an olefin-comprising feed to a hydroformylation, wherein the content of linear Ci-olefin having a terminal double bond in the stream fed to the hydroformylation stage is increased by means of a double bond isomerization by
Ia) feeding the olefin-comprising feed to a distillation column;Ib) taking off the stream enriched in linear Ci-olefin having an internal double bond in the lower part of the distillation column, at least part of the stream taken off is fed to a first reaction zone and reacting in the presence of a double bond isomerization catalyst;Ic) recirculating the output from the first reaction zone to the distillation column at a point above that at which the stream taken off in step Ib) is taken off; andId) taking off a stream enriched in linear Ci-olefin having a terminal double bond in the upper part of the distillation column, the stream taken off is fed together with carbon monoxide and hydrogen to a second reaction zone and reacting in the presence of a hydroformylation catalyst orIIa) feeding the olefin-comprising feed and also carbon monoxide and hydrogen a into a first reaction zone and reacting in the presence of a hydroformylation catalyst;IIb) separating off the stream comprising unreacted linear Ci-olefin having an internal double bond from the output from the first reaction zone and separating into two fractions of which at least one comprises unreacted linear Ci-olefin having an internal double bond;IIc) feeding the fraction comprising unreacted linear C;-olefin having an internal double bond which is obtained from step IIb) into a second reaction zone and reacting in the presence of a double bond isomerization catalyst; andIId) recirculating the output from the second reaction zone to step IIa) andwherein the isomerization catalyst and the hydroformylation catalyst are different catalysts,to give an n-valeraldehyde-comprising hydroformylation product;ii) subjecting the hydroformylation product to a separation to give an n-valeraldehyde-enriched fraction;iii) subjecting the hydroformylation product obtained in step i) or the n-valeraldehyde-enriched fraction obtained in step ii) to an aldol condensation; iv) catalytically hydrogenating the products of the aldol condensation by means of hydrogen to form alcohols; and v) optionally, subjecting the hydrogenation products to a separation to give a fraction enriched in 2-propylheptanol.