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Schlenk: Transfer of Liquids
Mostly the transferred liquids are solvents, because all reactions take place in solution and/or the desired products are solved. It's important to acknowledge, that all solvents are water and oxygen free and therefore may not come in contact with these. So septa, syringes and cannulas are needed. To prepare the flasks, inert gas flow is opened and the flasks are equipped with septa. The cavity on the bottom of a septum still contains oxygen. To rid this, the septum is lifted on one side to let the oxygen flow out, and put back. This repeated thrice to make sure all oxygen is gone. Now a syringe close to the desired transfer volume is chosen, because bigger ones tend to have more inaccurate scales. Another option is to weigh the syringe, to determine the used amount of solvent.
To get rid of oxygen in the syringe, the septum is punctured, some inert gas is taken into the syringe and blown out to the ambient atmosphere. This is also done thrice. Now the solvent can be taken into the syringe and transferred to another flask. If a bubble of inert gas forms, the syringe is turned until the cannula is at the top and the bubble can be blown out.
If the transferred amount is unimportant or huge, a transferring cannula can be used. Make sure the inert gas valves are open. The transferring cannula is pierced trough one septum and oxygen within the cannula flows out. Now it's pierced through the septum of the other flask and put into the solvent of the reserve flask. The septum of the targeted flask is punctured by a cannula. When the inert gas flow is drained, the excess pressure in the reserve flask forces the solvent through the transferring cannula into the target flask. To stop the transfer, inert gas flow is opened again and the cannula is removed.