Cannulation Technique Using a Schlenk Line

Take an oven-dried Schlenk flask and ensure it is properly sealed with a tightened stopcockand septum. Connect both the flask and dry solvent container to the Schlenk line, with the solvent under nitrogen (positive pressure) and the flask cooling under vacuum (negative pressure).

Open the flask to nitrogen so both the solvent container and flask are under positive pressure. Take a double-headed needle and insert one end into the septum of the solvent container and the other into the flask septum, keeping the tip just above the liquid surface in the nitrogen region.

Once both sides of the needle are connected between the solvent container and flask, push the needle tip into the solvent liquid. This sequencing minimizes contamination from entering the system.

Open the flask to vacuum slightly to create negative pressure, which pulls solvent from the closed container into the flask like drawing liquid through a straw.

Open the flask to nitrogen to reintroduce positive pressure and rebalance the pressure across the system, which stops the liquid from flowing.

Repeat the same cannulation steps using a round-bottom flask with tubing connected via a needle through a rubber septum. Pre-mark the desired solvent volume on the flask using water and a permanent marker, then oven-dry the marked flask overnight.

If solvent flow slows during transfer, open the flask to slight vacuum again to increase flow rate. Add substrate and stir bar to the dried flask before solvent transfer, or use a glove box for more rigorous anaerobic conditions.

Conclude the solvent transfer procedure. Use both hands when handling flasks and equipment in the lab for safety and stability whenever possible.