| 摘要 |
<p>1364796 Quinones F HOFFMANN-LA ROCHE & CO AG 17 May 1972 [17 May 1971 17 Dec 1971] 23119/72 Heading C2C A process for the manufacture of quinones o the general formula in which at least one of the symbols R 1 , R 2 , R 3 and R 4 represents a methyl group and the otherf symbols represent a hydrogen atom or a methyl group comprises oxidizing a phenol of the general formula in which the symbols R 1 , R 2 , R 3 and R 4 have the significance given earlier and the symbol X represents a hydrogen, chlorine, bromine or iodine atom with the acid of oxygen or an oxygen containing gas in a solvent in the presence of copper and halogen ions as a catalyst and, if desired, in the presence of a complexing agent, but only in an amount up to a ratio of copper atoms : complexing agent molecules which is equal to 1 : 2. Complexing agents mentioned include akyl or phenyl derivatives of trivalent elements of the fifth main group of the periodic system, e.g. amines, phosphines and arsines. Examples describe the preparation of 2-, 2,3-di-, 2,6-di-, 2,3,5-tri- and 2,3,5,6-tetramethyl quinones.</p> |
