Separation of metathesis catalysts and reaction products in flow reactors using organic solvent nanofiltration

Organic solvent nanofiltration (OSN), a relatively new low energy separation technology, has been used to reduce metal contamination of ring closing metathesis reaction products. The catalysts used were readily available commercial Hoveyda–Grubbs and Umicore M series catalysts. These reactions were performed in a flow reactor with in-line membrane separation, and high catalyst retention can be achieved. In the flow reactor set up a beneficial effect on catalyst life-time on changing from solvents such as dichloromethane to environmentally more benign acetone, which reduces initiation rates, was demonstrated.