Question

convert 1)propanoic acid to 3-pentanone 2)ethanal to 2-hydroxy 3-butenoic acid 3)ethanal to butanal

Answer 1

-Convert propanoic acid to 3-pentanone
3-Pentanone is produced industrially from propionic acid (which undergoes ketonic decarboxylation)using metal oxide catalysts (catalysts cerium (IV) oxide & manganese dioxide on alumina):
Catalyst
2CH3CH2CO2H→(CH3CH2)2CO+CO2+H2O
-Convert ethanal to 2-hydroxy 3-butenoic acid.
Acetldehyde(ethanal)undergoes cross aldol condensation with formaldehyde to give beta-hydroxypropanal which on heating gives propenaldehyde,which on reaction with HCN & on hydrolysis gives 2-hydroxy 3-butenoic acid.
-Convert ethanal to butanal
Acetaldehyde (ethanal)undergoes aldol condensation in the presence of base to form Crotonaldehyde.Then crotonaldehyde on catalytic dehydrogenation gives butanal.
Aldol
condensation
2CH3CHO→CH3CH=CHCHO+H2O
Ethanal Crotonaldehyde
Catalytic
dehydrogenation
CH3CH=CHCHO→CH3CH2CH2CHO
Crotonaldehyde Butanal