What Is the limiting reagent and percent yield of dibenzalacetone? Comment on th

Question

What Is the limiting reagent and percent yield of dibenzalacetone? Comment on the percent yield? What specific factors may have led to a toss of product? Comment on the identity and purity of the product! Do you observed melting point match the actual meting point of dibenzalacetone? My observed melting point is 108-110C and my observed mass of the product is 2.67grams. In this experiment, acetone is condensed with two equivalents of in the presence of base. The product, acetone, on stages other a few minutes. It is subsequently from the mature, washed, pressed dry, from ethanol, and characterized by mooting point analysis in a conical flask, dissolve 5 0g of sodium hydroxide in 50ml, of water 40 mL of ethanol swill to ensure that the solution is homogeneous. Mix51 mL of with 18 ml of acetone in attest tote: use append to add one-half of this mixture to the sodium hydroxide solution Swirl the reaction mixture occasionally. Asher 15 minutes at room temperature, add the remainder of the mixture and rinse the container with a little to complete the transfer. Swirl the reaction mixture for an additional 15 minutes, then collect the product by suction station on a Buchner funnel. Break the suction and carefully pour 100 mL of water on the product Reapply the vacuum. Repeat this process two more times in order to remove all traces of sodium hydroxide. Be sure to empty the between dress to prevent an overflow. Finally, press the product between two sheets of filter paper to remove as much

Explanation / Answer

Mass of Benzaldehyde = D*V = 5.1 mL * 1.044 g/mL = 5.3244 g of Benzaldehyde

mol = mass/MW = 5.3244 /106.12 = 0.050173 mol of Benzaldehyde

for acetne:

Mass of Acetone = D*V = 1.8 mL * 0.791 g/mL = 1.4238 g of Acetone

mol = mass/MW = 1.4238 /58.08  = 0.024514 mol of Acetone

ratio is 2:1 so:

0.050173 mol of B.A. -->1/2 *0.050173 mol of Acetone = 0.0250865 mol of Acetone

we do NOT have enouhg, so Benzaldehyde is limiting reactant

for the product:

ratio is 2:1 so:

0.050173 mol of B.A. -->1/2 *0.050173 = 0.0250865 mol of dibenzalacetone

mass expected (theoretical) = mol*MW = 0.0250865 *234.3 = 5.87776 g of dibenzalacetone

%theoretical = real/theoretical = 2.67/5.87776 *100 = 45.4254 %

b)

% yield is too low, this is mainly due to the TIME; nly 15 mins are alowed to react

the temperature is room temperature, trying another T might increase yield

Note that also NaOH might be high and ethanol could be higher in order to facilitate O-H and CO=O electron interaction

The identity of the final poduct --> most likely soluble in organic extraction

Finally

purity --> MP = 110-110 and we have 108-110°C this is slightly lower than the real value so this must have some impurities

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