Condensation Aldol Reaction of Benzaldehyde Derivatives and Acetophenone in 1-Dodecyl-3-methylimidazolium Bromide as Medium

• Main Author: QURROTUL AIN (NIM : 10513024), REZA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/30371
• Institution: Institut Teknologi Bandung

<p align="justify">Chalcone (&#945;,&#946;-unsaturated carbonyl) and 1,3-diketones are compounds that can be used as building block of heterocyclic and antioxidant compounds, therefore those compounds are potential to be developed. The 1,3-diketone can be synthesized by oxidizing the &#946;-hydroxy ketone compounds. However, the &#946;-hydroxy ketone compounds are particularly susceptible to dehydration resulting in &#945;,&#946;-unsaturated ketones. Aldol condensation reaction produced &#946;-hydroxy carbonyl and &#945;,&#946;-unsaturated carbonyl. In this study, the aldol condensation reaction was carried out by reacting benzaldehyde derivatives and acetophenone in ionic liquid medium of 1-dodecyl-3-methylimidazolium bromide (DDMIm)Br and under alkaline condition at 6 oC using various of reaction time and two oxidizing agents (KMnO4 and K2Cr2O7). Initially ionic liquid [DDMIm]Br were synthesized by MAOS (Microwave Assisted Organic Synthesis) method at irradiation power 300 W and 50 oC for 21 minutes with 57.58% yields. The characterization of 1H-NMR (500 MHz, CDCl3) showed the presence of 3 proton signals with multiplicity singlet in the aromatic regions (&#948;=7.5 - 10.5 ppm) and triplet proton signal (&#948; = 4.2 ppm) proving that the alkyl group has been attached to the atom N within the 1-methylimidazole structure. Meanwhile, the characterization of 13C-NMR (125 MHz, CDCl3) showed 16 signals corresponding to the amount of carbons with [DDMIm]Br structure. In the aldol condensation reaction directly continued by the addition of oxidator at the end of the condensation reaction produced &#945;,&#946;-unsaturated ketones (chalcone and 3-(4-methoxyphenyl)-1-phenylprop-2-en-1-one) with approximate 64 - 80% yields and having melting point of 55 - 57 oC. The formation of &#945;,&#946;-unsaturated ketones was also confirmed by the TOCSY 1D analysis of 1H NMR (500 MHz, CDCl3), showed by the presence of trans coupling (J = 15.75 Hz). The 1,3-diketone (dibenzoylmethane) with 83% yields and melting point of 78 - 80 oC was produced when the oxidizing agent was added at promptly the reaction by raising the temperature slowly to 15 oC.<p align="justify">