Aldol and 9fluro - lab report PDF

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8. discussion In this organic lab, the reaction between acetophenone and p-anisaldehyde that formed the product which is trans p-anisalacetophenone. The main purpose of this lab is to identify the melting point, percent yield, and IR graph to verify the final product. Therefore, it undergoes the condensation of cross aldol condensation because of alpha beta unsaturated carbonyl compound. The alpha hydrogen to the carbonyl and the polarity of carbon oxygen double bond is very important criteria. The polarity gives carbon a positive charge and oxygen to get negative charge. Therefore, the carbonyl can be an electrophile under acidic, or nucleophile under basic. If a carbonyl acts as a nucleophile, the alpha hydrogen carbonyl must be gone through deprotonation to make negatively charged alpha carbon ion. The deprotonation makes an enolate ion and tautomerize makes an enol. The product has two molecules which is constitutional isomer; which is that they have the same formula, but location of double bonds and hydrogens are switched. To compare between enolates and enols, enolates are more reactive nucleophile than enols and easy to make a second polarized carbonyl group. The alpha hydrogen only reacts to from an enolate. Therefore, Acetophenone can only makes one type of enolate. Also, a ketone and acetophenone enolate ion will not react each other because of the steric hinderance at the ketone carbonyl group. Also, the beta hydroxy carbonyl compound contains alcohol and carbonyl. To make alpha and beta unsaturated carbonyl compound, it needs dehydration. Usually, the aldehyde has a lower activation energy than a ketone that causes rapid dehydration. The beta hydroxyl carbonyl makes the carbon-carbon double bond and then hydroxyl functional group leaves. Finally, the trans isomer is created because it is more stable than cis compound.

9. Data and Results Analysis The final product, trans-p anisalacetophenone, mass was 0.271g, and it was very higher than any other result. Theoretical yield of the product was (0.224g/136.15g) = 0.0165 mol. 0.0165 mol * 238.28g (molar mass of trans p anisalacetophenone) = 0.393g. To calculate the percent yield, (0.271g/0.393g) * 100 = 68.96%. This percent yield was extremely high that there was the almost perfect recrystallization and filtration. There must be a product lose from the filtration and recrystallization but still over 60% is a very successful result. The melting point of this product was around 70-73 Celsius which

was

very

close

to

the

theoretical

melting

point

of

the

trans-p-

anisalecetophenone(73-76 Celsius) The impurities from the lab equipment or during lab cause melting point to be little bit lower than an actual value. However, this value was very close to the answer that it does not require second recrystallization. Also, the second recrystallization might lower the percent yield. According to the IR graph, it is very distinguishable to identify the trans-p-anisalacetophenone. There was a main peak at 3015cm^-1 which it indicates benzene ring and double bond. The next peak is located at 1610cm^-1 which it indicates the carbonyls group. The fingerprint region of the product was very similar to the actual region of IR graph. This can be concluded that the final product was p- anisalacetophenone. However, there were so many unrelated peaks were presented that impurities cause some of the inaccurate peaks to present.

10. Conclusion The overall result of this experiment went very well. The percent yield of this product was over 60% that it has very good filtration and recrystallization process. However, there were some impurities presence in the product that caused melting point to be lower than the actual value and irrelevance IR peaks had been presented. During this reaction the product color changed to clear and there was no major problem to change any results. To get better results on next time, it requires better filtration and needs slow down little bit to get better a result....