How do you convert ethanal to propanone?

Ethanal reacts with methyl magnesium bromide (Grignard reagent) followed by acid hydrolysis to form propan-2-ol. Oxidation of propan-2-ol with PCC (Pyridinium Chlorochromate) gives propanone. PCC oxidation converts secondary alcohol to ketone. Further oxidation to PCC does not happen with PCC.