“The Fischer esterification:
A catalyzed collaboration
‘Twixt alcohol, acid
Yields end product placid
Post sep funnel’s stratification.”
The next chemistry-themed limerick from NaPoWriMo2024 was posted on 21 April 2024 and provided an overview of a common organic chemistry reaction.
“The Fischer esterification…”
Named for chemist Emil Fischer (1852-1919), the reaction summarized here forms an ester. An ester is a type of functional group: a characteristic combination of atoms. This functional group is commonly abbreviated as “R-CO2R” and is illustrated at this outstanding website.
“A catalyzed collaboration /
‘Twixt alcohol, acid…”
This reaction has two reactants, one containing the functional group known as a carboxylic acid (R-COOH) and one containing the functional group known as an alcohol (R-OH). These would be written on the left-hand side of the reaction arrow. It can be catalyzed in the presence of a strong acid such as sulfuric acid (H2SO4); this could be denoted by writing the catalyst’s formula over the reaction arrow. A good illustration of the reaction overall can be seen here.
“Yields end product placid /
Post sep funnel’s stratification.”
The reaction forms an ester, with water as a side product; these are the compounds written on the right-hand side of the reaction arrow. The ester product is stable (“placid”) once formed, presuming reaction conditions allow that. [While that sounds tautological, this particular reaction is often used to explain to students how either side of a reaction equilibrium can be favored by shifting conditions, such as (here) adding excess reactants to preferentially generate the desired product.]
The work-up process in the organic lab is what happens after a synthesis reaction is run; it removes side products and leftover reactants, allowing a chemist to obtain and characterize a single purified product. Work-up often involves a step that separates the organic layer of the reaction mixture from the aqueous layer, using a piece of equipment called the separatory funnel: i.e., the “sep funnel’s stratification.”
Chemphasis 