preparation of acetylferrocene lab PDF

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lab report with yield data, properties, TLC analysis and discussion...

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An Ho (018305649)

Experiment 8: Preparation of Acetylferrocene, by Friedel-Crafts Acylation and purification by Column Chromatography

Balanced equation and mechanism:

An Ho

Exp #8 AcylFerrocene

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Yield Data: Table #1: Yield data of Acetylferrocene and Ferrocene Theoretical yield

Actual yield

Percent yield

Acetylferrocene

0.114 g

0.04 g

35.09 %

Ferrocene

N/A, starting material

0.003 g

N/A

Results: Table #2: Properties of Acetylferrocene and Ferrocene Acetylferrocene

Ferrocene

Molecular weight

228.08 g/mol

186.04 g/mol

Density

1.014 g/ml

1.11 g/ml

Melting point

83.6-84 C (lit. 81-83 C)

(lit. 172-174 C)

Product appearance

Solid: brown (with orange hint) powder Liquid: dark orange but translucent solution

Solid: pale orange/yellow color (almost white with an orange/yellow hint) Liquid: bright yellow, translucent solution

Analysis of Instramental Spectra and Chromatograms: Table #3: TLC analysis of Plate #1 developed in solvent mixture 1:1 Hexane:Methylene Chloride Compound spotted

Spot 1: Rf

Spot 2: Rf

Crude

0.20

0.80

1. Ferrocene

0.80

2. Acetylferrocene

0.20

Discussion: After data collection, the yield of Acetylferrocene is found to be 0.04g, which equals to 35% yield (table #1). This is quite low and could have been caused by evaporation on the heating

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Exp #8 AcylFerrocene

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plate. The eluting solvent takes up most of the volume and was quickly evaporated so this can lead to some solid being evaporated along with the solvent as well, resulting in a smaller yield. After weighing, solid Acetylferrocene was used to measure the melting point, which is 83.6-84 C (table #2). Compared to the literature value of 81-83 C, it’s a very good result, giving the conclusion that the isolation of Acetylferrocene is also successful, since the accurate melting point means it’s a pure substance. This can be verified again by the TLC analysis. As seen in table #3, the crude lane produces 2 spots with Rf of 0.20 and 0.80, representing Acetylferrocene and Ferrocene respectively. Lane #2, representing pure Acetylferrocene, produces a single similar spot with the same Rf of 0.20. Therefore, it can be confirmed that the collected Acetylferrocene is a pure substance.

Additional Questions: 1. Predict the order of elution of a mixture of triphenylmethanol, biphenyl, ben-zoic acid, and methyl benzoate from an alumina column. Starting with the compound that eludes the fastest, the order is biphenyl, methyl benzoate, triphenylmethanol, benzoic acid.

2. Once the chromatographic column has been prepared, why is it important to allow the level of the liquid in the column to drop to the level of the alumina before applying the solution of the compound to be separated? It is important because you don’t want the liquid and solution to get mixed together because that would lead to skewed results.

An Ho

Exp #8 AcylFerrocene

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