1. The organic layer is washed with a dilute sodium hydroxide solution to remove any remaining benzoic acid, as it is a polar compound and will dissolve in the sodium hydroxide solution, separating it from the organic layer.
2. To isolate the alcohol from the organic layer, the solution can be distilled to separate the alcohol from the other components. Any unreacted aldehyde can be further removed by carrying out a fractional distillation.
3. The Cannizzaro reaction is a disproportionation reaction where an aldehyde is both oxidized and reduced simultaneously, leading to the formation of a carboxylic acid and alcohol. An aldol reaction, on the other hand, is a condensation reaction between an aldehyde or ketone with an enolate ion to form a beta-hydroxy aldehyde or ketone.
4. Acidifying the aqueous layer helps to protonate any remaining carboxylate ions present from the washing with sodium hydroxide, converting them back to benzoic acid which can then be easily separated. The chemical equation for this reaction is:
NaOH + HCl → NaCl + H2O
For example, when benzoic acid reacts with sodium hydroxide, it forms sodium benzoate which can be protonated back to benzoic acid by adding hydrochloric acid:
C6H5COONa + HCl → C6H5COOH + NaCl
Under the synthesis of benzoic acid and benzyl alcohol answer these questions below
1. Why is the organic layer washed with a dilute sodium hydroxide solution
2. How would you isolate the alcohol from the organic layer that contains also the position of unreacted aldehyde?
3. What is the difference between the canizzaro reaction and an aldol reaction?
4. Why do we acidify the aqueous layer? Give give the chemical equation of the reaction. Give example
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