US 11,834,399 B2
Optimized thermal separation by prior gas exchange
Alexander Brächer, Haltern am See (DE); Ana Markovic, Haltern am See (DE); Anna Chiara Sale, Recklinghausen (DE); Dirk Fridag, Haltern am See (DE); Johannes Knossalla, Gahlen (DE); Peter Kucmierczyk, Herne (DE); and Robert Franke, Marl (DE)
Assigned to Evonik Operations GmbH, Essen (DE)
Filed by Evonik Operations GmbH, Essen (DE)
Filed on Feb. 6, 2023, as Appl. No. 18/165,245.
Claims priority of application No. 22155546 (EP), filed on Feb. 8, 2022.
Prior Publication US 2023/0250040 A1, Aug. 10, 2023
Int. Cl. C07C 45/50 (2006.01); B01J 31/18 (2006.01); C07C 45/77 (2006.01); C07C 45/78 (2006.01)
CPC C07C 45/77 (2013.01) [B01J 31/1845 (2013.01); C07C 45/786 (2013.01)] 20 Claims
 
1. A process for preparing an aldehyde, the process comprising at least:
a) reacting, in a hydroformylation, at least one C2 to C20 olefin with synthesis gas in the presence of a homogeneously dissolved catalyst system comprising at least one metal from the group consisting of Co and Rh, and a phosphorus ligand; wherein the hydroformylation is conducted in at least one reaction zone and at a pressure of 10 to 350 bar absolute, which affords a first liquid reaction output containing at least the aldehyde and unconverted olefins, and wherein a partial pressure of CO or H2 accounts for at most 70% of a total gas pressure of all gaseous substances present;
b) performing a gas exchange with the first liquid reaction output, which affords a second liquid reaction output in which the partial pressure of CO or H2 accounts for more than 90% of the total gas pressure;
c) expanding the second liquid reaction output obtained from b) in a single-stage or multistage expansion, to a pressure of less than 1 bar absolute, which affords a third liquid reaction output; and
d) feeding the third liquid reaction output obtained from c) to a thermal separation in order to separate the third liquid reaction output into a low-boiling fraction and a high-boiling fraction, with the low-boiling fraction containing at least a portion of the aldehyde.