This is the procedure for a Fe(III) catalyzed synthesis of aspirin, an alternative to the traditionally sulfuric acid catalyzed synthesis of aspirin. The prep compares and contrasts the Bronsted acid catalyzed esterification reaction with a Lewis acid iron (III) catalyzed pathway. This can be used in different courses at different levels, but is it written for a general/intro level chemistry course.
- Students will be able to compare and contrast Lewis Acids/Bases with Bronsted Acids/Bases
- Students will be able to calculate the moles of each reactant, the aspirin product, and the percent yield of product.
- Students will be able to determine the limiting reagent and calculate amount of excess material
- Students will characterize aspirin using melting point determination, IR and NMR spectroscopy and be able to distinguish the different structural elements between the starting material (salicylic acid) and the product (aspirin)
- Students will be able to differentiate between the Fe(III) catalyzed mechanism and the sulfuric acid catalyzed esterification mechanism
Inorganic Chemistry/upper level
- Students should be able to relate experimental observations (color) to the d-orbital splitting of Fe(III) complexes
- Students will be able to draw plausible intermediates and propose a mechanism for the iron catalyzed reaction in relation to the observed reaction colors
Erlenmeyer Flasks, Hot Plate, Balance, Vacuum Filtration, NMR and IR spectroscopy
Chemicals: Acetic Anhydride, FeCl3, Salicylic Acid, Water
Some notes have been included in the uploaded instructor notes.
We are interested to submit this to the Journal of Chemical Education, so we (the authors) would be very interested in examining any student data that anyone receives if using the procedure as written in addition to any modifications to the procedure for both general/intro level classes and upper level classes/labs.