Procédé de préparation de phénols, à partir des alpha, alpha-dialkyl-aryl-méthyl-hydroperoxydes

A process for the production of phenols comprises continuously contacting a hydroperoxide of the general formula:- R1 R2 C(OOH) Ar or R1 R2 C(OOH) Ar C(OOH) R3R4. wherein R1, R2, R3 and R4 are alkyl groups and Ar is an aryl or an aralkyl group in the former formula and an arylene or alkarylene group in the latter formula, in the liquid phase with an acid catalyst under substantially anhydrous conditions at a temperature between 70 and 85 DEG C. under reduced pressure sufficient to maintain the reaction mixture in a state of reflux, removing the heat of reaction as the latent heat of boiling of the reaction mixture and withdrawing part of the reaction mixture as reaction product. Ketones are formed as byproducts. The process may be carried out in the absence of added ketone solvents or in the presence of an amount of added ketone solvent less than that required to maintain the reaction mixture in a state of reflux at the reaction temperature of atmospheric pressure. Starting materials mentioned include a ,a -dimethyl-p-methyl benzyl-, a ,a - dimethyl benzyl-,a , a -dimethyl -pisopropyl benzyl-, a ,a -ethyl methyl benzyl, a ,a - dimethyl -pethyl benzyl and a ,a - dimethyl naphthyl methyl hydroperoxide, dihydroperoxides such as m-and p-diiso-propylbenzene and p-ethyl isopropyl benzene dihydroperoxides and hydroperoxides derived from naphthalene, anthracene and phenanthrene substituted with alkyl groups from methyl to butyl including the various isomeric forms both in the nuclei and on the carbon atoms to which the hydroperoxide groups are attached. The hydroperoxide may be in the form of a crude oxidation reaction mixture e.g. obtained by oxidation with oxygen or a pure hydroperoxide. The hydroperoxide may be obtained by fractionation of the oxidation reaction products at reduced pressures. In the production of phenol acetone may be added. Cumene hydroperoxide may be employed mixed with an inert solvent, e.g. cumene. Examples are furnished in which phenol and acetone are obtained by refluxing cumene hydroperoxide with a mixture of cumene, phenol, acetone and sulphuric acid at reduced pressures and fractionating the products. For comparison a similar process is carried out at normal pressure. The product is treated with aqueous sodium carbonate or caustic soda before fractionating to obtain the phenol and acetone.