Organic Chem II Lab
Friedel-Crafts Acylation of Ferrocene and Column Chromatography Introduction:
The intention of this lab is to analyze the formation of acetylferrocene using column chromatography. The Friedel-Crafts acylation reaction created acetylferrocene and diacetylferrocene, using phosphoric acid as a catalyst for the reaction between acetic anhydride and ferrocene (once applying heat). During column chromatography, a solution is passed through a filtration system of silica, sand, and cotton. This creates colored or colorless bands, dependent on the type of chemical compound, and is comparable to a reverse TLC test. The differences in polarity pull down the compounds at different rates, allowing for the separation.
Dry, sublimed ferrocene (93 mg) was added to a reaction tube. Later, 0.35 mL of acetic anhydride and 0.1 mL of 85% phosphoric acid were also added. The reaction tube was capped using a septum, and a syringe needle was poked through. This was warmed over a steam bath and stirred for 10 minutes after it began to boil, forming a dark brown color. The tube was then cooled to room temperature, then further cooled in ice. A solution of 0.5mL was added, dropwise w/ mixing. 3M NaOH was added until the pH of the solution was neutral. The product was vacuum filtrated and pressed dry.
The column was packed by adding cotton, then sand to the tip. A slurry of adsorbent and hexanes was created, then poured into the column. Most of the remaining solvent from the slurry was drained, but some minor bubbles formed in the sand. The compound was dissolved in a few drops of dichloromethane. 0.303 grams of adsorbent was added, and the solvent was evaporated. This was poured into the column. Some more solvent was added and the column was run. The first yellow band was run to near completion, but the bubbles in the sand made the column run too slow to finish the second band. Therefore, gravity filtration was used....
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