The Friedal-Crafts acetylation was used to react ferrocene with acetic anhydride to create acetylferrocene and perhaps diacetylferrocene by electrophilic substitution to an aromatic ring. The concept of thin layer chromatography was brought to our attention for the first time. It was used to analyze the reaction mixture. Also, the process of column chromatography was used to isolate and identify the products.
| |Ferrocene (reagent) |Acetic Anhydride (reagent) |Crude Product(g) | |Mass (g) |0.51 g |2.16 g |0.468 g |
|Products |Mass (g) |Rf |MP (ºC) |Percent Recovery |Characteristics | | | | | |(recrystallized)-Relative % | | | | | | |Column | | |Acetylferrocene (recrystallized)|0.013 g |0.231 |82-85.5ºC |5.24% |Orange needle rosettes | |Acetylferrocene (column) |0.11 g |0.476 |80-89ºC |55% |Grains with orange | | | | | | |pigment | |Ferrocene (column) |0.002g |0.571 |172-175ºC |Was not required in lab |Flakes that look yellow | | | | | |manual |and hard | |Diacetylferrocene (column) |0.003 g |0.095 |97-102ºC |1.5% |White and flaky |
|Product |Literature MP (ºC) |Experimental MP (ºC) | |Acetylferrocene (recrystallization) |85-86 (C |82-85.5ºC | |Acetylferrocene (column) |85-86 (C |80-89ºC | |Ferrocene (column) |174 (C |172-175ºC | |1,2 Diacetylferrocene (column) |96-97 (C |97-102ºC |
TLC of Reaction Mixture: TLC of Recrystallized Mixture:
|RFA |5cm/5.2 cm |0.9615 |
|RFB(bottom) |2cm/5.2 cm |0.3846 |
|RFB(top) |5cm/5.2 cm |0.9615 |
|RFA |1.2cm/5.2 cm |0.2308 |
TLC of Column Chromatography:
|RFA |3cm/5.25 cm |0.577 |
|RFB( |2.5cm/5.25 cm |0.476 |
|RFC |0.5cm/5.25 cm |0.095 |
When comparing the literature value of the acetylferrocene’s melting point and the experimental value of the acetylferrocene’s melting point , the values were very similar. The literature value of acetyl ferrocene is 85-86ºC. The value of the melting point of acetylferrocene after recrystallization was 82-85.5ºC, while the value of the melting point of acetylferrocente after column chromatography was 80-89ºC. The lab manual stated that the crystals of the acetylferrocene were supposed to resemble rosettes of orange needles, and this was exactly what the product looked like after the recrystallization procedure. Also, after the column chromatography the product was still orange as well.
The method of column chromatography also proved successful because it illustrates the major concept of polarity and it’s separation of the...