Acid-catalyzed hydrolysis of some primary alkyl phenyl ethers

Products were analyzed and rate constants of disappearance and hydrolysis, alkylation and/or rearrangement were measured for methyl, ethyl, propyl and allyl phenyl ethers by GC in concentrated aqueous perchloric acid solutions. Chlorination of the substrate and possibly of the product, phenol, was observed beside the hydrolysis of methyl phenyl ether and a slight chlorination of phenol beside the hydrolysis of ethyl phenyl ether. A marked Claisen rearrangement to isopropylphenols and alkylation to propyl isopropylphenyl ethers were observed in addition to the hydrolysis of propyl phenyl ether. The Claisen rearrangement to o-allylphenol was estimated to be quantitative in the case of allyl phenyl ether. The change of the reaction mechanism from A-2 (MeOPh and EtOPh) possibly via A-2(carbocation)(PrOPh?) to A-1 (allyl phenyl ether and possibly PrOPh) was deduced from the products, reaction rates, activation parameters, solvent deuterium isotope effect and parameters of excess acidity plots.