Crystalline alpha-zirconium phosphate intercalated with 1-ethyl-3-methylimidazolium chloride or 1-hexyl-3-methylimidazolium chloride, and crystalline gamma-zirconium phosphate intercalated with 1-ethyl-3-methylimidazolium chloride were synthesised, characterized and evaluated as selective catalysts in the Baeyer-Villiger oxidation of p-methoxybenzaldehyde, o-methoxybenzaldehyde and 2,4,6-trimethylbenzaldehyde by hydrogen peroxide, in glacial acetic acid or without solvent. The best selectivities of p-methoxyphenol (100 %), o-methoxyphenol (95 %) and 2,4,6-trimethylphenol (55 %) were achieved without solvent and are explained by the properties and structure of each catalyst.