| 摘要 |
Phenols and ketones are obtained by the decomposition of hydroperoxides of lower alkyl benzenes with aqueous sulphuric acid of a concentration of not less than 9 per cent w./w., the decomposition being effected at a temperature not exceeding 40 DEG C. The hydroperoxide starting materials are defined as those wherein the peroxide group is linked to an aliphatic tertiary carbon atom attached to the benzene ring and the alkyl groups do not contain more than five carbon atoms. The decomposition is preferably effected at 20 DEG to 40 DEG C. but lower temperatures, e.g. of about 0 DEG C., may also be used. It may be carried out by bringing the acid into intimate contact with a solution of the hydroperoxide in an inert water-immiscible solvent which may be the initial alkyl benzene from which the hydroperoxide is derived and it is preferred to use as such a solution the reaction mixture resulting from the oxidation of the alkyl benzene at elevated temperatures with molecular oxygen and the manufacture thereby of the corresponding hydroperoxide. The aqueous sulphuric acid may be used in concentrations as high as 65.0 per cent H2SO4 w./w. or even higher. The process may be carried out in a continuous manner and in this case it may be carried out in more than one stage, e.g. by using more than one reactor vessel in series. In the first vessel a fresh solution of the hydroperoxide in unreacted hydrocarbon is added continuously to the aqueous acid contained in the reactor at such a rate as to maintain the hydroperoxide concentration in the hydrocarbon at a constant level which is a fraction of the initial concentration of the added hydroperoxide solution. A part of the mixture of the aqueous acid and the oil phase which contains the decomposition products is passed continuously to a separator, the aqueous acid being returned to the reactor whilst the oil phase is made to overflow from the separator at a rate equal to that at which fresh hydroperoxide solution is fed to the reactor. The oil phase is then passed to a further reaction vessel or vessels where it is again contacted with aqueous acid to complete the decomposition of the hydroperoxide. Examples describe the decomposition of isopropylbenzene hydroperoxide to form phenol and acetone, the isopropyl hydroperoxide being used in the form of its solution in isopropylbenzene, both continuous and batchwise processes being described. Specifications 626,095 and 641,250 are referred to.
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