“Exacting; extracting…
A sep funnel’s function:
To isolate layers and
Compound obtain.
(Avoid a moment most
Melodramatical:
Ere product’s sure,
From waste’s discard,
Refrain!)”
The 8 April 2021 Twitter poem addressed another laboratory technique: using a separatory funnel, a specialized piece of glassware that allows a chemist to separate different components of a given reaction mixture (the environment in which the reaction has been taking place).
“Exacting; extracting… /
A sep funnel’s function: /
To isolate layers and /
Compound obtain.”
Each step of an organic synthesis depends on two key parts: the reaction itself, which converts reactant to product, and the work-up, in which the product compound is isolated (identified and purified), while excess solvents and side materials are discarded.
The separatory funnel (“sep funnel”), as its name suggests, is particularly useful in separating liquid layers from one another, based on their different densities. Often, the layers of interest are “water” versus “non-halogenated organic solvents,” where the latter layer would be less dense than the former. In the case of “water” versus “halogenated organic solvents,” through, the latter layer is more dense than the former. (Chemists typically use “aqueous” and “organic” as efficient shorthand for the layers.)
Either way, depending on which layer the target product occupies, the chemist will use the sep funnel, to “compound obtain.”
“(Avoid a moment most /
Melodramatical: /
Ere product’s sure, /
From waste’s discard, /
Refrain!)”
I suspect that anyone reading the discussion of different densities above, whether or not they are a chemist, might quickly note the most challenging hazard of using a sep funnel: being absolutely sure which layer is which (and which layer thus contains the product) before proceeding. A best practice is to wait to discard the other layer until subsequent steps are completed, to be sure the target product hasn’t been accidentally lost: “Ere product’s sure, / From waste’s discard, / Refrain!”
When a student is learning the technique, though, this lesson can sometimes be hard-won. This is unfortunately clear from the occasional “moment most / [m]elodramatical”… directly after the moment when someone’s synthesized product is inadvertently lost to the waste container.
Chemphasis 