Method for the hydroformylation of olefins
View Patent ↗The invention relates to a process for preparing alcohols by hydroformylation of olefins or olefin mixtures, separation from the catalyst and subsequent hydrogenation, with an extraction being carried out after removal of the catalyst and before the hydrogenation of the aldehydes.
1. A process for preparing aliphatic alcohols having from 7 to 17 carbon atoms, the process comprising one or more reaction stages which each comprise
a) hydroformylating olefins having from 6 to 16 carbon atoms in the presence of a catalyst which comprises cobalt to obtain a hydroformylation mixture,
b) treating the hydroformylation mixture with at least one gas which comprises oxygen in the presence of acidic, aqueous cobalt(II) salt solutions to obtain a second mixture,
c) separating the second mixture from said treating b) into an aqueous phase comprising cobalt salts and an organic phase comprising the aliphatic aldehydes,
e) extracting the organic phase from said separating c) with a liquid which comprises water
d) hydrogenating the organic phase which comprises the aliphatic aldehydes.
2. The process as claimed in claim 1 , further comprising
f) separating all or part of the second mixture from said treating b) by distillation into a low-boiling fraction comprising unreacted olefins and a bottom fraction comprising the aldehyde,
wherein, in said extracting e), the organic phase from said separating c) and/or the bottom fraction comprising the aldehyde from said separating f) is extracted with a liquid comprising water.
3. The process as claimed in claim 1 , wherein said extracting e) is carried out using pure water.
4. The process as claimed in claim 1 , wherein said extracting e) is carried out using an aqueous solution or a mixture of water with a mineral acid, a carboxylic acid and/or an organic solvent.
5. The process as claimed in claim 1 , wherein the pH of the liquid comprising water is less than or equal to 7.
6. The process as claimed in claim 1 , wherein the process comprises at least two reaction stages and all or part of the organic phase separated off in said separating c) is passed to said hydroformylating a) of the next reaction stage.
7. The process as claimed in claim 2 , wherein all or part of the low-boiling fraction separated off in in said separating f) is returned to said hydroformylating a).
8. The process as claimed in claim 2 , wherein the process comprises at least two reaction stages and the low-boiling fraction separated off in said separating f) is passed to said hydroformylating a) of the next reaction stage.
9. The process as claimed in claim 2 , wherein the process comprises at least two reaction stages and the low-boiling fraction separated off in said separating f) is passed to said hydroformylating a) of the next reaction stage and the bottom fractions separated off in said separating f) of all reaction stages are hydrogenated in a joint said hydrogenating d).
10. The process as claimed in claim 2 , wherein the process comprises two reaction stages and the low boiling fraction separated off in said separating f) of the first reaction stage is passed to said hydroformylating a) of the second reaction stage and the organic phase from said treating b) of both stages is passed to said separating c) of the first reaction stage.
11. The process as claimed in claim 2 , wherein the process comprises two reaction stages and the low boiling fraction separated off in said separating f) of the first reaction stage is passed to said hydroformylating a) of the second reaction stage and said treating b), said separating c) and said hydrogenating d) are each carried out jointly for the two reaction stages.