PROCESS FOR PRODUCING CRUDE AROMATIC DICARBOXYLIC ACID TO BE FED TO HYDROGENATION PURIFICATION

摘要

In a process for producing a high purified aromatic dicarboxylic acid by producing a crude aromatic dicarboxylic acid by liquid phase oxidation of an alkyl aromatic hydrocarbon with an oxygen-containing gas under the presence of a catalyst comprising Co, Mn, and Br, converting into an aqueous solution with water, and then conducting hydrogenation purification, economical production of a crude aromatic dicarboxylic acid containing 2,000 to 3,500 ppm of an aromatic monocarboxylic acid aldehyde for use in hydrogenation purification, and the controlled amount of the oxidation catalyst not giving undesired effects on the active life of the hydrogenation purification catalyst and reaction conditions therefor are proposed. Formation of an aromatic dicarboxylic acid by liquid phase oxidation of a dialkyl aromatic hydrocarbon with an acetic acid solvent is attained by decreasing the combustion amount of acetic acid lost in oxidation reaction, restricting the formation of an ash content in the resultant aromatic dicarboxylic acid and providing the compositional control for the oxidation catalyst by using a relation with the reaction temperature. That is, the catalyst is controlled by setting the reaction temperature to 185 to 197°C, and the amount of Co+Mn and the amount of Br/Mn ratio calculated by the relation equation correlating with the reaction temperature at least as a control amount at each of the reaction temperatures, within a range for the amount of Co+Mn of 2,650 ppm or less and the Br/(Co+Mn) ratio of 1.7 or less.