New review about the olefin metathesis under continuous flow mode

We came across a valuable review on olefin metathesis under continuous flow mode, and would like to share with you some of its insights. Dr Marc Mauduit and co-workers did a great job on addressing the key challenges in this area: 
1. Feasibility of metathesis in flow.
2. Catalyst cost.
3. Thermodynamics. 
4. Reaction selectivity. 
While all the above mentioned aspects are very important, we would like to focus a little more on the 3rd one - thermodynamics. As the authors pointed out: olefin metathesis is an equilibrium process so undesired by-product, ethylene, contributes to decrease of transformation efficiency.

Indeed, in the majority of cases ethylene needs to be removed efficiently in order to ensure high catalyst turn-over numbers and thus process economy. Beyond that, ethylene must be removed in accordance with safety and environment standards. 

Many of our clients noticed it even in a batch system, so you can imagine that in closed systems like flow reaction with limited headspace it is even more significant.  
Apeirons answer to this problem was a tube-in-tube reactor design. Where ethylene could be sucked into an inner permeable tube connected to a vacuum line. 

Tube in tube reactor

(Figure 1. tube-in-tube reactor link)

Another effective solution was developed by the world leader in flow chemistry, the Snapdragon company. It is a system using a semipermeable membrane, consisting of a perfluorinated polymer coated on a chemically resistant microporous layer. It allows selective infiltration of the ethylene.

We highly encourage you to read the whole article here 

At Apeiron Synthesis we are working on continuous and semi-continuous metathesis processes that can address these issues. So, if you think about scaling up the metathesis process do not hesitate to contact us!