is it other than CH3COOH + C2H5OH => CH3COOC2H5

Question

propanoic acid and isoamyl alcohol to make isoamyl propanoate?

Answer 1

Yes. CH3COOH and C2H5OH makes ethyl acetate or ethyl ethanoate.
You want propanoic acid and isoamyl alcohol to make isoamyl propanoate. I gave that ethyl acetate example to show you how it was named and put together. That's how I figure which is the alcohol and which is the acid to use.