Purpose:
The purpose of this experiment was to synthesize 4-chloro-4'-methoxychalcone from para-chlorobenzaldehyde and para-methoxyacetophenone by using an aldol condensation reaction. The compound was purified by recrystallization. The product was characterized by analyzing melting point, TLC, IR spectroscopy, 1H NMR spectroscopy, and mass spectroscopy.

Mechanism:
Key features of the aldol condensation reaction mechanism: (1) the formation of an enolate by an acid-base reaction; (2) nucleophilic attack of the aldehyde by the enolate in a nucleophilic addition type reaction; (3) deprotonation of water by the alkoxide creating an aldol product. The rest of the reaction undergoes an E1cB mechanism: (4) aldol is converted to an enolate ion …show more content…
0.530 grams of para-methoxyacetophenone and 0.495 grams of para-chlorobenaldehyde were used. This, however, did not change the mol ratios of the reaction. The product was washed with excess water during vacuum filtration, instead of 5-10 mL of water, to remove residual NaOH. The product was rinsed with ethanol during vacuum …show more content…
This stretch coincided with the alkene in the product, which is highly conjugated. This trans-disubsituted C=C bond in the molecule is also indicated by the absorption at 981.3 cm-1. The stretch at 873.2 cm-1 corresponds to a 1,4 disubsituted aromatic compound. Both of the benzene rings in the product are 1,4 disubsituted. The strong absorption at 1656.2 cm-1 correlates to a conjugated C=O stretch in the ketone, which are usually in the range 1700-1650 cm-1. There is no clear OH stretch present, which means that there is not a lot of EtOH impurity. Aldehyde C=O stretches usually show up at 1715-1680 cm-1, and there is no such peak present. Since there is an aldehyde subsituent on para-chlorobenzaldehyde, this is indicative of the fact that there is no starting material within the