GB724190A - Manufacture of phenol and acetophenone - Google Patents

Abstract

In the process for the manufacture of phenol by the acidic catalytic decomposition of isopropylbenzene hydroperoxide, phenol is separated from acetophenone by extracting the reaction mixture with an aqueous sodium hydroxide solution containing less than 15 grams of sodium hydroxide in 100 c.c. of water, separating the aqueous phase containing sodium phenate and recovering phenol by acidification, and recovering acetophenone by distilling the residue resulting from the above extraction. The preferred concentration of sodium hydroxide is from 5 to 10 grams in 100 cc. of water. The separation of the aqueous alkaline phase from the remainder of the mixture may be facilitated by the addition to the extraction mixture of a hydrocarbon which is readily separable from acetophenone, e.g. benzene, toluene or isopropylbenzene. The reaction mixture resulting from the acidic decomposition of isopropylbenzene hydroperoxide, which may contain phenyldimethylcarbinol, higher phenols (mainly p-cumylphenol), acetone and alpha-methylstyrene, may be distilled to remove acetone, any isopropylbenzene, alpha-methylstyrene, and the greater part of the phenol, and then further distilled to remove an azeotropic mixture of phenol and acetophenone which is subjected to the above extraction process. Alternatively, the acidic decomposition reaction mixture may be treated to remove acetone, alpha-methyl styrene and isopropyl benzene if present, and the remaining mixture is subjected to a pyrolysing heat treatment at temperatures of about 300 DEG to 400 DEG C., as described in Specification 670,444, to convert phenyldimethyl carbinol and p-cumylphenol into alpha-methylstyrene, isopropylbenzene and phenol, the mixture issuing from the pyrolyser being extracted with the aqueous sodium hydroxide solution. Part of the phenol may be removed from the mixture prior to the pyrolysing heat treatment, or alpha-methylstyrene, isopropylbenzene and the greater part of the phenol may be distilled from the product issuing from the pyrolyser before the extraction with aqueous sodium hydroxide is carried out. A number of detailed examples are given in which the concentration of sodium hydroxide is 10 and 5 grams of sodium hydroxide in 100 cc. of water.ALSO:In the process for the manufacture of phenol by the acidic p catalytic decomposition of isopropylbenzene hydroperoxide, phenol is separated from acetophenone by extracting the reaction mixture with an aqueous sodium hydroxide solution containing less than 15 grams of sodium hydroxide in 100 cc. of water, separating the aqueous phase containing sodium phenate and recovering phenol by acidification, and recovering acetophenone by distilling the residue resulting from the above extraction. The reaction mixture resulting from the decomposition of isopropylbenzene hydroperoxide, which may contain phenyldimethylcarbinol, higher phenols (mainly p-cumylphenol), acetone and alpha-methylstyrene, may be distilled to remove acetone, any isopropylbenzene, alphamethylstyrene and the greater part of the phenol, and then further distilled to remove an azeotropic mixture of phenol and acetophenone which is subjected to the above extraction process. Alternatively, the reaction mixture may be treated to remove acetone, alpha-methylstyrene and isopropylbenzene, and the remaining mixture is subjected to a heat treatment at a temperature of about 300 DEG to 400 DEG C. as described in Specification 670,444 to convert phenyldimethylcarbinol and p-cumylphenol into alpha-methylstyrene, isopropylbenzene and phenol, and the mixture resulting from the heat treatment is subjected to the extraction process referred to above. Part of the phenol may be removed from the reaction mixture prior to the heat treatment, or alpha-methylstyrene, isopropylbenzene and the greater part of the phenol may be distilled from the product resulting from the heat treatment before the extraction process referred to above is carried out.