Acetylferrocene Lap Report 2

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University of Cincinnati, Main Campus *

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2040L

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Chemistry

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Dec 6, 2023

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docx

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Acetylferrocene Lab Results Table and Mechanism: Compound Weight (g) Mols Theoretical Yield Percent Yield Melting Range Literature Melting Range Acetylferrocen e 0.115 g 0.00507 0.122 g 94.3% 80.8 o C – 82.3 o C 81 o C - 83 o C TLC Plate and Table: Discussion: The purpose of the Friedel-Crafts Acylation (Acetylferrocene) experiment was to use a Friedel-Crafts acylation mechanism to synthesize acetylferrocene. This was done by reacting Compound Distance Traveled Rf Value Dichloromethane Solvent 3.5 cm N/A Standard Ferrocene 3.4 cm 0.971 First Interim (impure) 3.4 cm 0.971 Third Interim (Acetylferrocene) 0.7 cm 0.2

ferrocene with both acetic anhydride and phosphoric acids. Then, the product was separated using column chromatography. The final product was the acetylferrocene, and weighed 0.115g, which resulted in a 94.3% yield. This is a high yield, but there was still room for error which will be talked about later in the discussion. The actual melting range of the product found was 80.8 o C – 82.3 o C and the literature melting range was 81 o C - 83 o C. This indicates the product that was found has some impurities, but is decently pure due to the closeness of the melting range temperatures. The TLC plate shows the standard ferrocene sample on the left side, the first interim taken in the middle, and the third interim take on the right side. The ferrocene traveled farthest up on the plate because it was the most polar substance. The first interim only shows ferrocene on the plate, meaning there was no final product lost here. The last (third) interim taken was the acetylferrocene and it was pure because no other spots showed at that position on the plate. The second interim taken (not shown) is likely to have both ferrocene and acetylferrocene in it due to the others not having a mix. There Rf values are stated in the table above. Because there was not a 100% yield, and the melting range was not exact, there is proof of error in the experiment. In the first step of the lab, a water bath was prepared. The water was supposed to be 85 o C - 90 o C. The actual temperature of the water was on the lower side of this range, which could have created error. Another place error occurred that resulted in lower percent yield is the second interim taken during the column chromatography portion. This likely had a mixture of both ferrocene and acetylferrocene because the column did not drop in a perfect ring. Questions: 1. Electron donating groups would prevent the Friedel-Crafts alkylation because they make the ferrocene more nucleophilic. This makes it a poor electrophile and would prevent the reaction from continuing. Electron withdrawing groups push the electron density away from the ring. This prevents aromatic electrophilic substitution from happening. 2. Metallocenes are not able to be nitrated because nitric acid is a strong oxidizing agent, or the metal would be oxidized. This would create an unstable anti-aromatic ring. The reaction will not occur because a reaction from an aromatic to an anti-aromatic is unfavorable and improbable. 3.

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