Organic Chemistry Lab Report - Dibenzalacetone Synthesis - PDF

6538084323 Vanessa Monica Fei Goeyardi DISCUSSION The mechanism above shows how dibenzalacetone was produced through aldol condensation. To further explain the mechanism, a resonance stabilized enolate ion was produced due to the deprotonation of a-hydrogen in acetone. The carbon on benzaldehyde get...

6538084323 Vanessa Monica Fei Goeyardi DISCUSSION The mechanism above shows how dibenzalacetone was produced through aldol condensation. To further explain the mechanism, a resonance stabilized enolate ion was produced due to the deprotonation of a-hydrogen in acetone. The carbon on benzaldehyde gets attacked by the electron pair in enolate ion. The pair of electrons on the negatively charged oxygen then attacks the hydrogen in water. Another resonance stabilized enolate ion is produced and results in a benzal group being formed. The mechanism is then repeated but this time to the other a-hydrogen on acetone which then finally results in dibenzalacetone. During this lab experiment, we conducted a TLC comparison between benzaldehyde, crude product and recrystallized product with a mobile phase of hexane : EtOAc in the ratio of 4:1. From my results, benzaldehyde (labeled as “1”) travels the furthest compared to the crude (labeled as “2”) and the recrystallized product (labeled as “3”). This means that benzaldehyde is more polar to the mobile phase and less attracted to the stationary phase (silica gel) than the crude and recrystallized product. My results also showed some trailing for all of them (benzaldehyde, crude product and recrystallized product) which could mean that there are some impurities in the solutions. From my melting point experiment, I achieved a range of 106.0°C - 110°C. When compared to the expected melting point from wikipedia (110°C), the melting point of my product and the expected melting point is about the same which suggests that my product is pure and that my product is actually dibenzalacetone. The error I had was the fact that during the recrystallization process, I added the ethanol too slow and added too much water so it took a lot of ethanol to make the solution clear again. CONCLUSION In conclusion, I achieved 0.281 grams of dibenzalacetone with a percentage yield of 29.6% and a melting point of 106.0-110°C through a based catalyzed reaction between 0.235 grams of acetone and 0.864 grams of benzaldehyde with acetone as the limiting reagent.