GB427145A - Improvements in or relating to the production of phenol - Google Patents

Abstract

<PICT:0427145/IV/1> Phenol is manufactured by dealkylation of its homologues in the presence or absence of metal oxides as catalysts, and at increased pressure, e.g. 300 atmospheres, the vapours of the phenols or substances containing them, in admixture with hydrogen or mixtures containing or giving rise to hydrogen under the reaction conditions, being heated suddenly to the reaction temperature favourable for the formation of phenol and varying with the phenol treated (e.g. from about 550 DEG C. for o-cresol to about 650 DEG C. for m- and p-cresols or even higher for some of the xylenols), and the reaction mixture after being kept at that temperature for a short time, e.g. from a few seconds to about 30 minutes, being rapidly cooled. The sudden rise of temperature may be brought about by the exothermic reaction of carbon monoxide or gases containing it with steam to produce hydrogen in the presence of the phenol vapours, or by mixing these vapours with suitable preheated hydrogen or hydrogen-containing gas, which may itself be produced by a previous reaction of carbon monoxide with steam. In the apparatus shown in the Figure, carbon monoxide or a gas containing it such as coke furnace gas, illuminating gas, producer gas, power gas or water gas is passed through a gas compressor, (not shown), into the heater A, and the phenol under treatment admixed with water is passed through a liquid compressor, (not shown), into the vaporizer and heater B. The two streams meet in C, where the reaction occurs, and the products pass to the precooler D, where they are rapidly cooled, and the final cooler E, and are collected in the receiver F, the outlet tubes of which are provided with closing members r. Alternatively, steam may be introduced separately into C by a third tube, or the phenol and carbon monoxide or gas containing it may be introduced through one tube and the steam through another. In a modification of the apparatus, the carbon monoxide and steam are caused to react in a preliminary chamber and the resulting hot gas is then allowed to react with the phenol vapours which are introduced separately. As starting materials may be employed cresols, xylenols or higher phenols or mixtures thereof, e.g. phenol mixtures from coal tar, low temperature tar or brown coal tar, or oils rich in phenols, e.g. carbolic oils, cresol oils, low temperature oils, brown coal tar oils or the tars themselves.