EXP283

=Researcher= Matthew McBride =Objective= To synthesize trans-dibenzalacetone from acetone and benzaldehyde in an ethanol solvent using piperidine as the catalytic base =Procedure= Piperidine was added to ethanol and this solution was mixed. In a separate vial, benzaldehyde and acetone were added together in a 2:1 molar ratio. This benzaldehyde and acetone mixture was added drop-wise to the ethanol solution. The solution was then refluxed until the yellow product crystals formed. The reaction was monitored by HNMR. The following [|Reaction Preparation Sheet] was used to plan the synthesis. =Results= The following [|HNMR Spectrums] show the contents of the reaction mixture at T=0 hours (when the reactants were first added), T=1 hour and T=4 hours. A spectrum of the benzaldehyde used for this reaction was also included. =Discussion= The NMR analysis indicated that there was no peak around 10ppm present at T=0 hours to indicate the presence of benzaldehyde, but that peak was present at T=1 hours (10.03 ppm). The peak was not present at T=4 hours. The acetone peak at 2.5ppm was present in T=0 hours and T=1 hour, but greatly reduced in the T=4 hour spectrum. The doublet present in the T=4 hours spectrum at 7.1 ppm indicate that a small amount of dibenzalacetone formed. =Conclusion= No trans-dibenzalacetone was produced. Product was successfully obtained in EXP284. =Log=

2012-07-16
11:56 Added 20 mL of ethanol to a 50 mL Erlenmeyer flask. 12:02 Added 5.1245 g of piperidine to the flask and placed on stir plate. 12:11 Added 0.8639 g of acetone to a 5-dram snap cap vial. 12:14 Added 3.1393 g of benzaldehyde to the 5-dram vail. 12:18 Added contents of 5-dram vial with acetone and benzaldehyde to the 50 mL flask drop-wise as the solution was stirring. Removed a few drops of the reaction mixture and added to inner coaxial NMR Tube 1. Applied heat to the reaction mixture to reflux. 12:50 Placed Tube 1 in a thin-walled NMR tube holding CDCl3 and analyzed the sample by 500 MHz HNMR. The file of the spectrum was saved as UCEXP283_t0 (reaction time = 0 hours). 13:20 Reaction mixture obtained more of a yellow color. A few drops of the reaction mixture was removed and placed in inner coaxial HNMR Tube 2. 13:24 A few drops of benzaldehyde was added to inner coaxial HNMR Tube 3. 13:46 NMR Tubes 2 and 3 were analyzed by 500MHz HNMR and the files were saved as UCEXP283_t1 (reaction time = 1 hour) and UCEXP283_benzaldehyde. 16:57 A few drops of the reaction mixture was removed from the yellow solution. No crystals were visible. The few drops were added to inner coaxial NMR Tube 4. Tube 4 was placed in a thin-walled NMR tube containing CDCl3 and the sample was analyzed by 500MHz HNMR. The file of the spectrum was saved as UCEXP283_t4 (reaction time = 4 hours). The flask was removed from the hot plate and allowed to cool to room temperature.

2012-07-17
9:35 No crystals were visible in the solution. The solution was a yellow color. Placed the solution on ice. 11:00 No crystals formed from the solution.