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Synthesis of E, E-dibenzalacetone (E, E-DBA) Lab Report

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Abstract

The main purpose behind this experiment was to synthesize E, E-dibenzalacentone by use of a based-catalyzed aldol condensation reaction. Secondly, this experiment was aimed at identifying characteristics of crude and purified samples of E, E-dibenzalacentone by use of the melting point determination method. The results from this experiments showed that the synthesis process yielded 65% crude E, E-dibenzalacentone and 56% yield for purified E, E-dibenzalacentone. When it comes to the techniques that were used, the researchers employed Hirsch funnel and solid-liquid extraction as part of the separation techniques. Lastly, recrystallization of the E, E-dibenzalacentone was also used as a purification technique.

Introduction

The synthetic goal of this experiment was to make use of a based-catalyzed aldol condensation in the entire process of synthesizing o E, E-dibenzalacentone. The other main goal of this experiment was to identify or to characterize crude and purified samples of E, E-dibenzalacentone by use of the melting point determination

Results

The results of the synthesis of E, E-dibenzalacentone are summarized below

Discussion

The E, E-dibenzalacentone was prepared by combining 0.250 mL of Benzaldehyde, 0.1mL of reaction grade acetone, 0.5 mL of 95% ethanol and 1 mL of a catalyst solution in a 10 mL round bottom flask. The catalyst solution that was used in this experiment has been prepared earlier by dissolving 10g of sodium hydroxide in 100 mL of water and 75 mL of 95% ethanol. The main purpose of this catalyst was to speed up the reaction process. A micro scale condenser was attached to the round bottom flask and the reactants were gently mixed for about 15 minutes, until a solid started forming. Then the crude solid was isolated by pouring the mixture into a Hirsch funnel attached to the vacuum filter, thus allowing the solid crude E, E-dibenzalacentone to be trapped by the filter paper in the Hirsch funnel. 

An RB flask was de-attached from the condenser after which it was rinsed with 20 mL of de-ionized water at one time, 3 times totaling 60 mL, to gain any residue thus E, E- dibenzalacentone was left in the round bottom flask. The dried solid was transferred to a pre-weighed Erlenmeyer flask where its mass was measured and the results were 0.65 g=65%. A small sample of the crude solid was taken and smeared on a microscope slide by use of the flat end of the micro spatula after which a melting point capillary tube was used to get approximately 2mm of crude product. A Mel-Temp device was used to find out the melting point of the crude product 108-109Co

The crude product was purified using recrystallization methods. The solubility of E, E- dibenzalacentone in ethanol at 78 is 0.4g/1mL. Based on my 0.39g, this ratio was used to determine that 0.985 mL of 95% ethanol should be used. The solution was heated in a fume hood until the sample was dissolved, and then cooled at room temperature upon which it was placed in an ice bath to produce maximum crystals. Steps were taken to filter the solid with a Hirsch funnel, and then weighed to produce 0.07 g of purified E, E- dibenzalacentone. Although a significant amount of product was lost, it is likely that a lot of the loss was impurities, and after the melting point was later taken, it was found that the amount of purified E, E- dibenzalacentone was pure. The dried, purified product was removed from the Hirsch funnel and its mass was taken and recorded before its purity was assessed.

Experimental Procedure

The preparation was carried out according to the prescribed method.