Method for reclaiming oxidation catalyst

Abstract

The invention relates to an oxidant catalyst recycle method, wherein in the reaction solvent with low-order carboxyl acid of fatty group, with heavy metal catalyst and bromine catalyst, it uses oxygenmolecule to oxidize the alkyl aromatic compound to produce the carboxyl acid in aromatic group, to recycle the oxidant catalyst with high recycle ratio; and when heating and concentrating the oxidantreaction mother liquid, mixing and heating said concentrated object; then mixing and granulation the hot slurry, to form granulation slurry; the heating process and granulation process are treated inmixing rove, to separate the solid and liquid of granulation slurry, to recycle separated catalyst water solution.

Description

technical field [0001] The present invention relates to the recovery of oxidation catalysts represented by cobalt, manganese and bromine at high yields from the mother liquid of the oxidation reaction of alkyl aromatic compounds in the production process of aromatic carboxylic acids represented by terephthalic acid method. Background technique [0002] As the SD method, in the well-known production process of terephthalic acid, p-xylene is oxidized by air under the condition that cobalt compound, manganese compound, bromine compound, etc. are used as oxidation catalysts, and acetic acid aqueous solution is used as a reaction solvent. , to manufacture terephthalic acid. Using methods such as centrifugation, solid-liquid separation is carried out on the terephthalic acid slurry after the reaction, and the separated terephthalic acid block is dried to obtain crude terephthalic acid. On the other hand, the oxidation reaction mother liquid is recycled and reused in the oxidatio...

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Problems solved by technology

However, the miniaturization of such particle groups deteriorates the solid-liquid separation property of the granulated slurry, and the catalyst aqueous solution increases with the solid residue, so there is a problem that the recovery rate of the oxidation catalyst cannot be improved.

Furthermore, in the bromine catalyst contained in the oxidation reaction mother liquor, most organic bromine compounds are hardly dissolved in the water phase of the granulation slurry, thus, after the catalyst aqueous solution is heated and concentrated, the p-xylene is recovered During the oxidation process, there is a problem that the recovery rate of bromine catalyst in the catalyst recovery process is very low compared with the recovery rate of about 80% or more of heavy metal catalysts such as cobalt and manganese, only about 30%

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