Limitations

Question 1

Acid and ester equilibrium problem (Dehydrate/excess reagent/H+)

Answer 1

Limitation 1: Difficult to remove excess reagent and reagents may be expensive/difficult to obtain to be using in excess.

Limitation 2: Alcohol must be stable enough to the acidic conditions, this is to avoid dehydration of -OH into an alkene.

Question 2

Carbonylation of Grignard reagents (benzene)

Answer 2

This does not work in presence of an acidic group such as phenol as grignard reagents are strong bases.