Emerging trends The emerging trends in
H /CO
Aldehydes
Alkene
hydroformylation focus on advanced catalyst design for higher selectivity and stability, process intensification for efficiency and sustainability, the use of renewable feedstocks, and catalyst recycling. These trends collectively aim to make hydroformylation a more sustainable, cost-effective, and versatile industrial process. 7,8,9 Recent innovations focus on improving catalyst efficiency, selectivity, and sustainability. Recyclable and reusable catalysts, such as rhodium nanoparticles supported on silica, are reducing costs and environmental impact. Advanced ligand systems,
[Rh]
O H
linear
+
branched
O H
H
[Rh]
[Rh]
H
–H O
Alkene-isomers
Alkane
Alcohol
OH
H [Rh]
Aldol condensation product
O H
H
OH
OMe Biphephos
OMe
O
O
tBu
tBu
O O P P O O O O
O O P P O O O O
O O
O
P
P
O
O O
Figure 5 Catalyst and the ligand system play an important role in obtaining the desired selectivity in the hydroformylation process
operating temperature and pressures. In addition to selective product formation, an efficient hydroformylation process requires effective catalyst recovery, streamlined product separation, and optimised feed-gas recycling to ensure overall process efficiency (see Figure 4 ). Both the choice of catalyst and the associated ligand system play a crucial role in determining the success of the hydroformylation reaction, influencing factors like reaction rate, selectivity, and stability. While for Rh-catalysed hydroformylation of a terminal alkene, where the most desired product is the linear aldehyde, other hydrogenated products such as alkane and alcohols can be produced (see Figure 5 ). Aldol condensation products from aldehydes can also be formed if the catalyst and process are not properly optimised. The LP Oxo Selector M30 hydroformylation technology employs Dow's Normax ligand system, a specialised rhodium-based catalyst designed for the LP Oxo Process. Known for its high linear-to-branched aldehyde selectivity from short-chain olefins, this system offers several advantages, including superior linear aldehyde yields, lower operating pressures and temperatures, reduced energy consumption, and enhanced cost efficiency through lower capital and operating expenses compared to conventional cobalt-based processes.
including bulky phosphines, phosphites, and N-heterocyclic carbenes (NHCs), are enhancing linear aldehyde selectivity and catalyst stability, especially for rhodium-based processes. A major trend is the transition from homogeneous to heterogeneous catalysis to overcome issues such as catalyst separation, metal leaching, and solvent use. Porous organic polymers with immobilised rhodium single sites now enable nearly 100% metal utilisation, negligible leaching, and solvent-free operations. This technology is proven at industrial scale, as seen in Ningbo, China, where a plant produces 50 kilotons per year of propanal and n-propanol. Low-pressure cobalt hydroformylation is also gaining traction. Breakthroughs by Evonik and LIKAT9 show cobalt carbonyl catalysts operating efficiently at lower pressures, offering energy and cost savings for long-chain alcohol production such as isononanol. Emerging greener processes use solid catalysts with isolated metal atoms for gas-phase ethylene hydroformylation, enabling the valorisation of refinery off-gases and shale gas. Further efficiency gains come from integrating hydroformylation with hydrogenation or aldol condensation, while biphasic systems like the Ruhrchemie/Rhone-Poulenc process enhance catalyst recycling and process sustainability. Emerging hydroformylation catalyst technologies include:
Refining India
20
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