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3.4 Drying


3.4.1 Procedure

  1. Dry to Organic Layer: After removing your solution from the aqueous phase, a drying agent is added to remove all traces of water. This is usually MgSO4, more effective and faster, but slightly acidic; or Na2SO4, less effective and slower, but neutral. These compounds bind to any water remaining in the organic solution, forming clumps when they react. A decent amount of drying agent should be added, but as long as some solid is not clumped, no more needs to be added. (This will make sense once you've done this a couple of times.)

  2. While the compound is drying, it is time to flute the filter paper. Some chemists prefer to use a Büchner funnel and unfluted filter paper (or a fritted funnel) under mild vacuum as their standard filtration method. Their motive is a slightly higher yield of product.

  3. Filter the solution into a large round bottom flask using your expertly fluted filter paper and a large funnel (or the Büchner method). To guard against bumping on the rotovap, do not fill the flask more than half full.

  4. Concentrate the solution on the rotovap then dissolve the compound in a small amount of solvent and transfer to a small pre-weighed (tared) flask.


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