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Researcher

Matthew McBride

Objective

To synthesize trans-dibenzalacetone using NaOH as the catalytic base and in an excess of benzaldehyde using a modification of the procedure listed in this article

Procedure

(1E,4E)-1,5-Diphenyl-1,4-pentadien-3-one: A stirred solution of NaOH (0.753 g, 18.83 mmol, 1.17 ep to acetone) in distilled water (40 mL) at room temperature was added to a stirred solution of benzaldehyde (4.2931 g, 40.48 mmol, 2.52 eq to acetone) in ethanol (40 mL). Acetone (0.9310 g, 16.04 mmol) was added to the reaction mixture. The reaction mixture was then stirred at room temperature for 40 minutes. The product was recovered by suction filtration, washed 1x with 1:1 ethanol/water, dried over suction for 40 minutes, and recovered (3.1808 g, 84.7%) as yellow crystals (mp 100-101°C).

Results

Reaction Sheet
Characterization of Product 285A
Amount: 3.1808 g
Appearance: Yellow crystals
Melting Point: 100-101°C
HNMR Spectrum of UCEXP285_A
Purity: Slight ethanol impurity present

Discussion

Successfully filtered solution to obtain product, because the product was insoluble in the ethanol/water mixture.

Conclusion

3.1808 g of pure trans-dibenzalacetone was produced in a yield of 84.7%

Log

2012-07-19

15:25 0.753 g of NaOH pellets were added to a 250 mL Erlenmeyer flask (Flask #1).
15:27 40 mL of distilled water was added to Flask #1 and the flask was placed on the stir plate with a stir bar.
15:30 40 mL of ethanol was added to a 125 mL Erlenmeyer flask (Flask #2).
15:34 4.2931 g of benzaldehyde was added to Flask #2.
15:39 0.9310 g of acetone was added to a 5-dram vial.
15:40 The contents of Flask #2 (benzaldehyde in ethanol) was added to Flask #1 as it stirred.
15:41 The acetone was added to Flask #1 as it stirred. The solution stayed clear but obtained a slight yellow color.
15:47 The solution became thick and yellow from the formation of yellow crystals.
16:27 The flask was removed from the stir plate and filtered using a Buchner funnel and suction filtration. The yellow crystals were captured on the filter paper and washed with a 1:1 ethanol/water (vol) mixture. The crystals were spread across the filter paper over the suction to dry. This is Product 285A.
16:44 An empty 5-dram vial (Vial #1) weighed 11.9939 g.
17:07 An empty 5-dram vial (Vial #2) weighed 11.9615 g.
17:11 The dried crystals were removed from the suction and the filter paper and placed in the 5-dram vials. Vial #1 weighed 16.6650 g with product (4.6711 g of product). Vial #2 weighed 14.4473 g with product (2.4858 g of product). This is a total of 7.1569 g of product.
17:14 0.1173 g of Product 285A was added to a 5-dram vial and approximately 0.4 mL of CDCl3 was added to the vial. The solution was transferred to the NMR Tube 1 and analyzed by 500MHz NHMR. The file of the spectrum was saved as UCEXP285_A.

2012-07-25

9:50 Weight of Vial #1 with the product was 15.9571 g. Weight of Vial #2 with the product was 13.1963 g. This is a total of 5.1980 g of product.

2012-07-26

9:37 Weight of Vial #1 with the product was 15.7432 g. Weight of Vial #2 with the product was 13.0239 g. This is a total of 4.8117 g of product.

2012-07-30

10:22 Weight of Vial #1 with the product was 15.19180 g. Weight of Vial #2 with the product was 12.7101 g. This is a total of 3.9465 g of product.

2012-08-27

14:55 Weight of Vial #1 with the product was 14.4370 g. Weight of Vial #2 with the product was 12.6992 g. This is a total of 3.1808 g of product.

2012-08-28

11:44 The melting point of Product 285A was measured to be 100-101°C.