Innovative Membrane processes for sustainable production for fine Chemistry – MemChem

At industrial scale, separation/purification processes represent from 40% to 70% of the operational costs (not including the cost of raw materials). They contribute to about 45% of the total energy consumption needed for a product elaboration. They correspond to conventional operations among them:

- liquid-liquid extraction needs high volumes of organic solvents thus generating volatile organic compounds. Such extraction can be followed by a precipitation step that can lead to the inactivation of some components during the phase change or by a distillation associated to high energy consumption , moreover not well adapted to molecules potentially degraded at high temperature among which are some molecules issued from bio-resources.

- chromatography (more rarely used) is an efficient process but implies generally a re-concentration step also energy intensive.
These operations are in fact far from the green chemistry principles.

The MemChem project aims at contributing to renew of industrial process through the use of eco- compatible separation processes

The MemChem project mainly focuses on the integration of organic solvent nanofiltration (OSN) in the process of hydroformylation of olefins. This separation technique performed at room temperature without any change of state is an innovative alternative to energy-intensive industrial operations such as cascades of liquid-liquid extraction and distillation discussed above. Besides reducing the metal content in the products, OSN will allow to recycle expensive compounds: rhodium catalyst and free ligands that are essential to the reaction.

This study will be discussed from different points of view:

a) molecular engineering around the catalyst used in hydroformylation and optimization of batch reactors aiming at favouring reactions without solvent, in order to increase the selectivity and productivity of the catalytic reaction together with the increase of the OSN separation

b) membrane modification obtained by cold plasma activation and deposition of polyelectrolytes on commercial membranes, in order to increase membrane performances (flux and selectivity of separation)

c) OSN study with commercial membranes, in order to identify pertinent parameters (cross- flow velocity, concentration factor, transmembrane pressure, …) in order to achieve the target separations. If commercial membranes are not sufficiently selective, the OSN cascade will be performed.

The project deals with "sustainable chemistry" and contributes to the challenge "stimulate industrial revival" by developing a novel approach that will be transferable to other reactions catalyzed by homogeneous organometallic complexes.

To evaluate the possibility of transposition/generalization of results obtained from the hydroformylation study, a second reaction (olefin metathesis) will be more punctually studied. In both cases, substrates used will be from renewable origin.