Question

how to convert ethanal to but-2-ene.

Answer 1

Answer:

On treatment with dilute alkali, ethanal gives 3-hydroxybutanal which on heating produces but-2-enal. (iii) When treated with Tollen's reagent, But-2-enal produced in the above reaction produces but-2-enoic acid .

Answer 2

Ethanal can be converted into but-2-ene by the following sequence of reactions :

• Firstly, addition of alkali leads to an aldol condensation reaction which forms 3-hydroxy butanal.
• 3-hydroxy butanal on heating produces but-2-enal by the loss of water .
• Treating but-2-enal with NaBH4 yields but-2-enol.
• But-2-enal is treated with HI to form 1-iodo but-2-ene.
• 1-iodo but-2-ene on treatment with LiAlH4 produces but-2-ene as a substitution producy of iodide ion with hydride ion.