Science Experiment

Experiment2: Preparation of Dibenzalacetone

Aim:

Using the cabon-cabon bond making ability in carbonyl chemistry, Dibenzalacetone is synthesized from 2 equivalent of benzaldehyde and 1 equivalent of acetone in a base catalyzed reaction.

Physical Data1: *detailed risk and safety phrases are attached.

substance Hazards, risks and safety practices MW (g/mol) Amt. Used Mol. mp (K) bp (K) density(g/cm^3)

acetone R11, R36, R67, S9, S25, S26 58.08 0.24 g 0.004 178.2 329.4 0.79

benzaldehyde R22, S24 106.13 0.82 g 0.008 247 451.1 1.0415

ehtyl acetate R11, R36, R66, R67, S16, S26, S33 88.11 2 ml per gram n/a 189.55 350.25 0.897

NaOH R35,S22, S26, S38, S45, S62, s24/25 39.997 0.4 g 0.01 591 1663 2.1

Ethanol R11, S2, S7, S16 46.07 2 ml n/a 158.8 351.6 0.789

Dibenzalacetone n/a 234 g/mol n/a n/a 379 unknown unknown

Theoretical Yield:

Limiting reagent: acetone (0.004 mol)

Presuming 100 % of limiting agent makes dibenzalacetone

Dibenzalacetone (100% yield) = 0.004 mol * 234 g/mol = 0.936 gram

The theoretical yield of dibenzalacetone is 0.936 gram

Procedures:

In a 50 ml conical flask sodium hydroxide (0.4g, 0.01 mol), distilled water (2 ml) and ethanol (2ml, 95%) were mixed into a clear solution. The solution was then cooled to room temperature. Benzaldehyde (0.8ml; 9.82g, 0.008mol) was then added to the solution followed by addition of acetone (0.3ml; 0.24g, 0.004mol) and formed into a thick yellow solution. The flask was then swirled gently and constantly for 5 minutes. This turned into a fluffy precipitate as the flask was swirled. After 5 minutes