| 摘要 |
1511181 Preparation of terephthalic acid by oxidation of p-xylene IMPERIAL CHEMICAL INDUSTRIES Ltd 30 March 1976 [11 April 1975 8 Aug 1975] 14964/75 and 33204/75 Heading C2C The invention comprises a process for the continuous manufacture of terephthalic acid which comprises introducing into an oxidation zone a liquid phase mixture of acetic acid solvent (consisting of acetic acid and water) and pxylene containing a catalyst, the ratio of acetic acid solvent in the reaction mixture in the oxidation zone to p-xylene fed to the oxidation zone being maintained within the limits of 4 : 1 to 7 : 1 by weight, passing a free-oxygencontaining gas through said mixture in the oxidation zone, and maintaining the temperature of said mixture in the oxidation zone between 160‹ to 180‹ C. and the proportion of water in the acetic acid solvent in said mixture between 1 and 7% by weight, the catalyst being a mixture of a cobalt compound, a manganese compound and bromine or a bromide in which the proportion of cobalt compound, determined as metal, is from 1200 to 2500 parts by weight per million of acetic acid solvent present in the reaction mixture in the oxidation zone, the proportion of manganese compound, determined as metal, is from 1 to 30% by weight of the weight of the cobalt compound, determined as metal and the proportion of bromine or bromide is at least 1À5 times the combined weight of the cobalt and manganese compounds, determined as metals, the mean residence time of the said mixture in the oxidation zone being from ¢ to 2 hours. |
