Patent GB-761152-A (GB)
Title: The purification of aromatic dihydroperoxides
Inventor: WEBSTER WILLIAM
IPC: C07C409/12
Filed: 1954-01-12
Abstract: Crude meta- and/or para-di-isopropylbenzene dihydroperoxide admixed with meta- and/or para - (2 - hydroperoxy - 2 - propyl) phenyl dimethyl carbinol, referred to as carbinol hydroperoxide, is purified by contacting the crude mixture dissolved in an organic solvent with aqueous sodium hydroxide solution so as to precipitate the di-isopropylbenzene dihydroperoxide as the sodium salt, the concentration of the sodium hydroxide solution being between 3N and in an amount such that when the salt has been precipitated, the normality of the excess sodium hydroxide present is not greater than 8N.  The hydroperoxide solution may be obtained by oxidation of di-isopropylbenzene in the liquid phase at elevated temperatures with oxygen, the crude dihydroperoxide mixture separated by extraction from the reaction mixture with a non-acidic medium such as 1-10 per cent aqueous sodium hydroxide or potassium hydroxide or water, and precipitated therefrom with CO2, filtered and dissolved in the organic solvent or extracted with the solvent after precipitation. The concentration of the crude dihydroperoxide mixture may be 10-50 per cent w/v. in the organic solvent which in the case of the meta-dihydroperoxide may be an aromatic hydrocarbon such as benzene, toluene, xylene, cumene or cymene or a halogenated hydrocarbon such as chloroform, carbon tetrachloride or tetrachlorethane and in the case of either the meta- or para-dihydroperoxide, an aliphatic ether such as diethyl ether or di-isopropyl ether, a ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, an ester such as ethyl acetate or amyl acetate or an aliphatic alcohol or hydrocarbon.  The dihydroperoxide solution is mixed with the sodium hydroxide solution with stirring, the di-isopropylbenzene di-hydroperoxide sodium salt is filtered off, washed with organic solvent or with 3-8N sodium hydroxide solution and the dihydroperoxide liberated by solution in water and precipitation with OC2.  The carbinol hydroperoxide may be recovered from the sodium salt filtrate.  The separation of the dihydroperoxide from a mixture with carbinol hydroperoxide by fractional crystallization using a mixture of benzene and petroleum ether is also mentioned.  In examples (1) and (2) a crude hydroperoxide mixture obtained by oxidation of meta-di-isopropylbenzene and extraction of the reaction product with 4 per cent aqueous sodium hydroxide is fractionally crystallized from benzene/petrol to give metadiisopropylbenzene dihydroperoxide, the residues being dissolved in benzene and shaken with aqueous sodium hydroxide according to the process of the invention, the sodium salt filtered off and acidified in aqueous solution with carbon dioxide to yield meta di-isopropyl benzene dihydroperoxide; (3) meta-di-isopropylbenzene dihydroperoxide and carbinol hydroperoxide in methyl isobutyl ketone are stirred with aqueous sodium hydroxide, the precipitated sodium salt being worked up as in (1) to give meta-di-isopropylbenzene dihydroperoxide; (4) to (7) further illustrate the use of methyl isobutyl ketone as organic solvent.  Specifications 641,250 and 646,102 are referred to, and Specifications 716,675, [Group IV (a)], and 727,498 are referred to in the Provisional Specification.