The H NMR and C NMR spectra to be annotatetd are for dibenzalacetone.

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Remember to use all the concepts/keywords which are listed ther Important: disregard m.p. data and discussion of it. In the results section present all your results. Next, in the discussion section elaborate on the meaning of these results (discuss). • Report and discuss theoretical yield, actual yield, % yield, recovery yield, % recovery yield. Show your calculations (calculations can be typed in or picture from lab notebook will suffice). • Report and discuss IR spectrum of your product. Present your data in a usual table format having complete peak analysis, draw structure of your compound on all your spectra and label all the peaks. Discuss similarities/differences; Compare and contrast IR spectra of synthesized dibenzalacetone with starting materials. Identify and discuss possible impurities. Attach the original spectra at the end of your report. • Report and discuss ¹H and 13C NMR spectra of product. Present your data in a usual table format having complete peak analysis, draw structure of your compound on all your spectra and label all the peaks. Discuss signals in the context of structure elucidation; Identify and discuss possible impurities. Attach original spectra at the end of your report (paste it into Word file). It is very important not to forget about thorough and detailed discussion of Claisen-Schmidt condensation reaction mechanism in all its steps.
Purpose Synthesis and characterization of dibenzalacetone this experiment you will synthesize dibenzalacetone by using aldol condensation reaction. The product will then be recrystallized and characterized by m.p. and IR analysis. Background information The reaction of an aldehyde with a ketone is the aldol condensation reaction. The reaction between an aldehyde/ketone and an aromatic carbonyl compound lacking an alpha-hydrogen is called the Claisen-Schmidt condensation. In this laboratory exercise, you will synthesize dibenzalacetone by condensation of two equivalents of benzaldehyde with one equivalent of acetone. The aldehyde carbonyl is more reactive than that of the ketone and therefore reacts rapidly with the anion of the ketone to give b- hydroxyketone, which easily undergoes base-catalyzed dehydration (Figure 36). By varying the amounts of the reactants in this Claisen-Schmidt reaction it is possible to obtain either the mono- or di-substituted benzalacetone. We will prepare dibenzalacetone, which is easier to isolate from reaction mixture. In the present experiment, enough ethanol is present as a solvent to dissolve the starting material, benzaldehyde and it's intermediate - benzalacetone. The benzalacetone undergoes second condensation reaction forming final product-dibenzalacetone. 2 only acetone dibenzalacetone Figure 35. The overall reaction scheme for dibencalacetone synthesis. benzaldehyde NaOH The synthesized dibenzalacetone will be collected by Hirsch funnel filtration, recrystallized from ethanol and further characterized.
In the laboratory The essential reactants for dibenzalacetone synthesis are provided in Table 1. oblast transm Mein Baby Table 1. Compound benzaldehyde acetone 95% ethanol 10% NaOH MW amount used 106.04 212 μL 58.08 les al downl Reactants used 46.07 74 μL 1.5 mL 2 mL immol (calculate) (calculate) sollemson bp (°C) 178 56 78 naft 70 d (g/mL) 1.04 0.79 0.78 Experimental procedure: reaction setup To a 4 mL conical vial add 2mL of 10% of sodium hydroxide solution and a magnetic spin vane. Next, add 1.5 mL of 95% ethanol and stir it on a magnetic stirrer. After that, add 212 µL of benzaldehyde and keep stirring. The benzaldehyde initially insoluble will go into solution and a clear (pale yellow) solution is obtained. Next, add 74 μL of acetone and continue to stir. At some point, a yellow solid should form. Continue stirring the reaction mixture vigorously for another 20 min. At the end of that time, yellow, flaky crystals should be observed. After that time, cool the reaction mixture in an ice bath and isolate the product by vacuum filtration using Hirsch funnel. Wash it 2 times with ice-cold water (using Pasteur pipette). Weigh and record the amount of your crude product.
Next, TA will prepare a water bath. You will prepare a separate tube, add-2 mL of ethanol to it and heat it in water bath. Transfer your product into large test tube. Using a minimal amount of hot ethanol (from your hot ethanol tube) dissolve your dibenzalacetone. You will want to keep your tube in a water bath while dissolving the product. After you obtain a translucent solution, remove your tube from the bath and let it cool down to room temperature. Once reached, place your tube into ice bath to further cool it down. Keep it on ice for 5 minutes and then filter it off using Hirsch funnel. Dry your product in the oven (TAs will set the oven temperature) and keep it for 10 min in there. Obtain mass of your recrystallized product and calculate the recrystallization yield. Product characterization Take your recrystallized product and record IR, 'H NMR and 13C NMR spectra. Record the m.p. of your product as well. The m.p. apparatus should be operated in a range of 80-150 °C. Your TA will set it up for you.
Reaction: наси нася сна H₂C 0 NaOH NaOH dibenzalacetone HC 0 0 dibenzalacetone
4000 3500 1000 500 3000 2500 Wavenumbers (cm-1) 2000 1500 0 5 1701.89 10 15 20 1203.61 746.97 %Transmittance 1592.71 827.16 688.91 649.84 09 2817.78 2737.34 1165.59 88 1654.65 1310.35 1454.88 75 80 1391.15 3062.483033.54 3387.74 2696 04 85 1287.80 8 8 8 1071.46 1016.31 ww
4000 3500 3000 2500 Wavenumbers (cm-1) 2000 1500 1000 500 To 9 10 15 1716.80750.83 1364.78 1223.95 25 30 35 acetone %Transmittance 531.92 1423.29 65 70 75 3006.48 2971.63 8888 1679.65 1094.23 2925.97
4000 3500 3000 2500 Wavenumbers (cm-1) 2000 1500 1000 500 56 & 8 729.16 62 692.11 64 66 1649.27 68 1625,81 980.45 760.13 %Transmittance NN 1214.36 76 1589.45 1341.97 78 1191.36 80 5.56 82 1573.17 1307.43 1100.18 84 86 883.54 1447.21 88 1494.56 3052.99 -06 923.65 1283.89 1259.51 1156.34 1075.18 1028.64 848.89 92 94 3025.79 dibenzalacetone
8.5 ory 70x 70% 192 nay- 8.0 -7.60 EVE -740 FOR J 7.5 OFE 602 -7.10 7.06 F-150 7.0 6.5 ZOOM 7.8 6.0 -7.75 <-7.72 7.7 5.5 5.0 -06-2 7.6 7.5 4.5 4.0 f1 (ppm) 9882 RRRK 7.4 f1 (ppm) 3.5 7.3 3.0 2.5 7.2 2.0 -7.10 -7.06 7.1 1.5 7.0 1.0 0.5 0.0 000-
-108.88 190 180 170 160 150 -143.28 140 134.80 130.48 128.95 128.77 128.38 -125.43 130 120 110 146 144 142 100 fi (ppm) 77.36 CD03 -7724 76.72 CDC3 -77.04 CDC 80 ZOOM chloroform 140 138 136 70 60 -134.30 134 f1 (ppm) 50 OT- 132 130 40 30 -129.95 - 128 126 20 DFRI- 10 124 0 00:01
Dibenzalacetone Results: Mass of the crude dibenzalacetone = 145.3mg Mass of the dibenzalacetone after recrystallization: 0.0925g