Project no. 426
Resource Efficiency with Biphasic Asymmetric
K. S. S. Jensen
DTU Chemistry, Technical University of Denmark
Anything produced in chemical industry requires resources, both in terms of starting
materials and the energy needed to supply the conditions necessary for the reaction to run.
For the production to be more sustainable, less resources should be used. Catalysis is
generally a way to do this, firstly by increasing selectivity so that less starting material is
wasted, and secondly by making the reaction run at milder conditions which require less
Besides from getting the best possible performance, a challenge of catalysis is to be able to
use less catalyst and to use for as long as possible, as the catalyst is also a resource.
The specific reaction of this project is asymmetric hydroformylation of alkenes to aldehydes.
Aldehydes are useful starting points in the production of other both bulk and fine chemicals.
In this reaction there is selectivity both in terms of getting the aldehyde rather than
something else, and getting the right aldehyde.
The proposed solution is a biphasic system, where the reaction works at room temperature.
It consists two immiscible liquids, an ionic liquid phase and an organic phase and the
catalyst is a Rhodium complex with a chiral phosphite ligand. This Rhodium-phosphite
complex gives selectivity towards a specific aldehyde. The catalyst is dissolved in the ionic
liquid and the product of the reaction is in the organic phase. This means that after reaction
the two phases can be easily separated, and the product will be in one, and the catalyst in
the other and can then be reused.
When the catalyst is dissolved, each catalyst complex can react, as opposed to in solid form
where only the ones at the surface are available because the rest are “hidden” behind them,
so more catalyst would be necessary to get the same effect.
HOW THIS IS A SUSTAINABLE SOLUTION
In summary, the main ways that this system is sustainable is:
- The Rhodium-phosphite complex ensures good selectivity, which leads to more of
the starting material turning into the desired product.
- It can run at room temperature which means no energy is needed for heating.
- The biphasic system lets the catalyst be dissolved and immobilized at the same
time so each catalyst complex is available for reaction and it can still easily be
reused. Both these things lead to less catalyst being necessary.