Advertisements
Advertisements
Question
Describe the following:
Cross aldol condensation
Advertisements
Solution
When aldol condensation is carried out between two different aldehydes and/or ketones, it is called cross aldol condensation. If both of them contain a-hydrogen atoms, it gives a mixture of four products. This is illustrated below by the aldol reaction of a mixture of ethanal and propanal.
Ketones can also be used as one component in the cross-aldol reactions.
APPEARS IN
RELATED QUESTIONS
What is meant by the following term? Give an example of the reaction in the following case.
Aldol
How will you convert ethanal into the following compound?
Butane-1, 3-diol
How will you bring about the following conversion in not more than two steps?
Benzaldehyde to 3-Phenylpropan-1-ol
What is substituted imine called?
Which product is formed when the compound 
is treated with concentrated aqueous \[\ce{KOH}\] solution?
Compounds A and C in the following reaction are:
\[\ce{CH3CHO ->[(i) CH3MgBr][(ii) H2O] (A) ->[H2SO4, Δ] (B) ->[Hydroboration oxidation] (C)}\]
When liquid ‘A’ is treated with a freshly prepared ammoniacal silver nitrate solution, it gives bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogensulphite. Liquid ‘B’ also forms a white crystalline solid with sodium hydrogensulphite but it does not give test with ammoniacal silver nitrate. Which of the two liquids is aldehyde? Write the chemical equations of these reactions also.
Convert the following:
Acetaldehyde to But-2-enal
Explain Aldol condensation of ethanal.
Which of the following does not give aldol condensation reaction?
Which of the following compounds will undergo self-condensation in the presence of dilute NaOH solution?
Assertion (A): The final product in Aldol condensation is always α, β-unsaturated carbonyl compound.
Reason (R): α, β-unsaturated carbonyl compounds are stabilised due to conjugation.
Identify A and B:
When acetaldehyde is treated with dilute NaOH, the following reaction is observed.
\[\begin{array}{cc}
\ce{2CH3 - CHO ->[dil.NaOH] CH3 - CH - CH2 - CHO}\\
\phantom{...............}|\\
\phantom{.................}\ce{OH}
\end{array}\]
- What are the functional groups in the product?
- Can another product be formed during the same reaction? (Deduce the answer by doing atomic audit of reactant and product).
- Is this an addition reaction or condensation reaction?
Write a note on the aldol condensation reaction of acetaldehyde.
What is aldol condensation? Explain it with suitable examples.
