REARRANGEMENT OF ALKYL PHENYL ETHERS TO ALKYLPHENOLS IN THE PRESENCE OF CATION-EXCHANGED MONTMORILLONITE (M(N-MONT)())

The rearrangement of alkyl phenyl ethers such as 4-phenoxybutan-2-one 1, 1-phenoxybutane 2a, 2-phenoxybutane 2b, 2-methyl-2-phenoxypropane 2 c and phenoxycyclohexane 2d have been investigated in the presence of cation-exchange montmorillonite (Mn+ -mont;M(n+) = Zr4+, Al3+, Fe3+ an d Zn2+). The ether 1 rearranged to 4-(4-hydroxyphenyl)butan-2-one 3 (r aspberry ketone), the odour source of raspberry, in 16-34% GLC yield, where Zn2+ -mont was the most effective catalyst. Similarly, other eth ers 2a-d rearranged to the corresponding alkylphenols in up to 75% iso lated yield with good product selectivity, Al3+ -mont being the cataly st of choice. Al3+ -Mont was regenerated and reused in the rearrangeme nt of 2b, 2c and 2d.