Patent GB-1032252-A (GB)
Title: Hydroxymethyl anthraquinone ethers and their use in the manufacture of hydrogen peroxide
IPC: C07C50/24
Filed: 1962-12-17
Abstract: In the manufacture of hydrogen peroxide by the method in which an anthraquinone derivative is alternately reduced and re-oxidized, use is made of 2-hydroxymethylanthraquinone ethers of the formula <FORM:1032252/C1/1> in which R is a saturated organic radical (see Division C2).  The ethers in which R is n-butyl, n-amyl, 2-ethoxyethyl or b -ethoxyethoxyethyl are particularly suitable.  The reaction may be effected in a solvent or a mixture of solvents, the specified solvents being n-butyl oxide, a mixture of methylcyclohexyl acetate and xylene, anisole, benzyl oxide, heptyl acetate, diisobutyl ketone, amyl acetate and a mixture of anisole and heptyl acetate.  In a preferred process the b -ethyoxyethoxyethyl ether is used in a solution of substantially equal volumes of anisole and heptyl acetate.ALSO:2-Hydroxymethylanthraquinone ethers of the formula <FORM:1032252/C2/1> in which R is an organic radical, are prepared by reacting 2-chloromethylanthraquinone with an alcohol in a non-basic medium at a temperature above about 100 DEG  C., if necessary under pressure.  The ethers in which R is methyl or ethyl may also be prepared by treating 2-hydroxymethylanthraquinon with dimethyl or diethyl sulphate in an acetonic medium containing potassium.  The ethers in which R is 2-chloroethyl, 2-methylpropyl, n-pentyl, 3-methylbutyl, n-octyl, n-dodecyl, allyl, 2-methoxyethyl, phenylmethyl, 2-phenylethyl or cyclohexyl are claimed as new compounds.  In general, R may be an alkyl, haloalkyl, hydroxyalkyl, alkoxyalkyl, dihydroxyalkyl, dialkoxyalkyl, acyloxyalkyl, carboalkoxyalkyl, alkenyl, aralkyl, cycloalkyl or cycloalkenyl group. Examples are given of the manufacture of the methyl, n-butyl, 2-methoxyethyl, b -ethoxyethoxyethyl and cyclohexyl ethers, and the melting points and certain solubility properties of the ethyl, 2-chloroethyl, n-propyl, isobutyl, 2-ethoxyethyl, n-pentyl, isopentyl, n-heptyl, n-oxtyl, n-dodecyl, phenylmethyl and phenylethyl ethers are also given.  The 2-chloromethylanthraquinone used as starting material is obtainable by treating 2-methylanthraquinone with sulphuryl chloride in the presence of a radical reaction initiator, e.g. azoisobutyronitrile, optionally in the presence of a solvent, e.g. carbon tetrachloride or chlorobenzene, and examples of this reaction are given. If the reaction is prolonged, 2-dichloromethylanthraquinone is obtained.  The 2-hydroxymethylanthraquinone, which may be used for making the methyl and ethyl ethers, is obtainable by heating 2-chloromethylanthraquinone with dimethyl sulphoxide in a non-basic aqueous medium, and an example of this reaction is given also.  If the reaction of 2-chloromethylanthraquinone with an alcohol is carried out with sodium alcoholate or in the presence of caustic soda or sodium carbonate, ethers of the formula above are not obtained, the product being bis-(anthraquinonyl-21)-1,2-ethane.  If pyridine is used as a hydrogen-chloride acceptor, the desired ethers are again not obtained, the product being N-anthraquinonyl-2-methylpyridinium chloride.  Products of the formula above in which R is a saturated group are useful in the production of hydrogen peroxide by the method in which an anthraquinone drivative is alternately reduced and reoxidized (see Division C1).