Procedures:

Step | Procedure | Observations | 1 | Mix 0.025 mol benzaldehyde with the theoretical quantity of acetone in a 100 mL beaker. | The solution had a strong smell, and clear color. | 2 | Make a solution of 2.5 g of sodium hydroxide dissolved in a 25 mL of water and 20 mL of ethanol in a 250 mL beaker. | The three solutions were added together, strong smell and clear color as well. | 3 | Add one-half the benzaldehyde-acetone mixture to the ethanolic NaOH solution and mix well w/ a stirring rod. | The solution turned yellow immediately, with some precipitations. | 4 | After 10-15 min add the remainder of the aldehyde-ketone mixture and rinse the beaker with a little ethanol. | After 10 min the solution left was added but no change occurred. | 5 | Stir the mixture frequently for 30 min and then collect the product by vacuum filtration on a Buchner funnel. | Mixture was stirred for 30 min, then transferred into the B. funnel. | 6 | Release the vacuum and carefully pour
50 mL of water on the product to wash it.
Reapply the vacuum and repeat this process 3 times. | Product was washed 3 time with water without releasing the vacuum. | 7 | Finally press the product as dry as possible on the filter using cork or 50 mL beaker, then press it between sheets of filter paper ( Save sample for mpt.) | A filter paper was placed on top of the crystals and a 50 ml beaker was placed on top of paper and pressed down. | 8 | Recrystallize the rest of the product using 5 mL of ethanol for each 4 g dibenzalacetone. | 4 mL of ethanol was added to the solution. | 9 | Add the product dissolve in hot ethanol then cool to room temp. Place it in ice bath (the yield after recrystallization should be about 2 g) | The product was added to the hot ethanol after it was completely dissolved was placed inside ice bath. | 10 | Perform infrared and measure melting point. Weigh the product and calculate percent yield. | The melting point of recrystallization was 105˚C. |

Calculations: Calculations | Results | Funnel w/ product - Empty funnel | Final Crude Product | 18.959 g - 15.597 g | 3.362 g (crude product) | Funnel w/ product - Empty funnel | Final Pure Product | 17.998 g - 15.786 g | 2.212 g (pure product) |

Percentage Yield Calculations:

Supporting Data and Documentation: Name | Data | Benzaldehyde | 2.683 g | Acetone | 0.776 g | NaOH | 2.514 g | Water | 25 mL | Ethanol | 20 mL | Empty funnel | 15.597 g | Funnel with crude product | 18.959 g | Empty funnel | 15.786 g | Funnel w/ pure product | 17.998 g | Melting pt range (crude product) | 101˚C | Melting pt range ( pure product) | 105˚C |

Results and Discussion: In this experiment the ethanolic solution composed of Acetone and Benzaldehyde were added to the aqueous sodium hydroxide. The two moles of belzaldehyde acted in response with both acidic α-protons of the acetone. Throughout the combination dehydration of the aldol product occurred. Dibenzalacetone, the final product, was precipitated right after mixing all the solutions with a yellow color and a pleasant smell. The product was then filtered from the combination, washed away, constrained dried and recrystallized from the hot ethanol. Melting point range were determined after crystallization with 101˚C and recrystallization with a 105˚C, which is very close to the melting point in the text book (113˚C). Percent yield of the recrystallization was calculated with a 72.62 %. Some of the final product was lost while doing the recrystallization. Infrared Spectroscopy was also determine. The IR Spectrum was very similar to the one in the book. The first peak observed was at 690.88 cm-1 which means C-Br stretch (alkyl halides). Another peak was at 979.15 cm -1 with a =C-H bend (alkenes). The third peak was at 1590.62 cm-1 with a C-C stretch (aromatics). Finally the last peak was at 1648.42 cm-1 with a –C=C- stretch (alkenes).

Conclusions & Suggestions: In conclusion the purpose of this experiment which was to synthesis Dibenzalacetone was accomplished with the procedures used in this lab. If this experiment, however, were to be repeated a higher percent yield could be achieved by being more careful when transferring solutions from one place to another. Also during the vacuum filtration some of the particles of the final product could be left behind.

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