Technology

Hydroformylation, or oxo synthesis, is an important industrial process that forms the first step in oxo alcohol and chemical production. During the reaction, an aldehyde is formed by reacting an olefin (alkene) with syngas (CO and H₂). The LP Oxo℠ Process uses a rhodium-based hydroformylation catalyst, which enables low pressure operation, high efficiency and a simple configuration for the oxo alcohol plant.

Butyraldehyde is produced by reacting propylene with carbon monoxide and hydrogen. The major product is the straight chain normal-butyraldehyde with a smaller amount of branched chain iso-butyraldehyde. The reactions are carried out at mild temperature (< 100°C) and low pressure (< 20 bara) in the presence of a homogeneous rhodium based catalyst with a phosphine ligand in the case of LP Oxo SELECTOR^SM 10 technology to provide a normal-butyraldehyde isomer ratio of 10:1. An alternative is the LP Oxo SELECTOR 30 technology which enables a normal to isomer ratio of 30:1 utilising the proprietary NORMAX™ Catalyst, an organophosphite ligand available from Dow.

Normal-butanol (n-butanol), 2-ethylhexanol (2-EH), iso-butyraldehyde (iBal) and iso-butanol (i-butanol) - all key oxo alcohols - can be produced from the hydroformylation of propylene via a mixed butyraldehyde stream. 

Figure 1 - Hydroformylation of Propylene.^[2]

The intermediate aldehyde is then converted into an oxo alcohol by hydrogenation. This happens in the liquid phase, which eliminates the need for a recycle compressor and makes the reactor smaller and simpler, saving cost and space.

References

1. Hydroformylation Technology, Johnson Matthey. (Accessed 29^th Nov 2024)
2. Oxo Alcohols Process - LP Oxo℠ Technology, Johnson Matthey. (Accessed 29^th Nov 2024).