Hydrogenation-technology
Hydrogenation technology
Hydrogenation is a key part of the oxo alcohols process for the production of oxo alcohols, where aldehyde produced by hydroformylation or aldolisation is hydrogenated to produce oxo alcohols.
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Hydrogenation in the oxo alcohols process
In the LP Oxo Alcohols process, alcohols are produced by low pressure rhodium-catalysed hydroformylation of an olefin with syngas (CO and H2) followed by hydrogenation of the intermediate aldehyde.
For example, propylene is hydroformylated to produce normal-butyraldehyde and iso-butyraldehyde which are then hydrogenated to produce normal-butanol and iso-butanol respectively:
2-ethylhexanol (2-EH) is produced from normal-butyraldehyde in two reaction steps. The first step is the aldolisation of normal-butyraldehyde to butyraldol and dehydration of butyraldol to produce 2-ethyl 3-propyl acrolein (EPA). The second step is the hydrogenation of EPA to 2-EH:
Two options are available for hydrogenation. In the liquid-phase hydrogenation scheme the reactions are carried out in the liquid phase over a heterogeneous catalyst at a temperature of approximately 160°C and at pressure below 30 bara. In the vapour-phase hydrogenation scheme the reactions are carried out in the vapour phase over a heterogeneous catalyst at a temperature of approximately 170°C and at pressure below 6 bara.
The crude alcohol produced in hydrogenation is refined to produce the final product 2-ethylhexanol, normal-butanol and iso-butanol.