Method for reclaiming oxidation catalyst

A technology of oxidation catalyst and recovery method, applied in chemical recovery, physical/chemical process catalyst, metal/metal oxide/metal hydroxide catalyst, etc. Deterioration of separability and other problems, to reduce the loss of oxidation catalyst, reduce environmental load, and be beneficial to industrial production.

Active Publication Date: 2006-10-11
MITSUI CHEM INC
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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%

Method used

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Examples

Experimental program
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Embodiment 1

[0056] use figure 2 The symbols of are used to describe the steps of Example 1.

[0057] Manganese acetate tetrahydrate (manufactured by Wako Pure Chemical Industries, Ltd., purity 99%) containing 700 ppm in terms of cobalt atoms of cobalt acetate tetrahydrate (manufactured by Osaki Kogyo Co., Ltd., with a purity of 98% or more), and 300 ppm in terms of manganese atoms, 90% acetic acid aqueous solution of 1200ppm hydrobromic acid aqueous solution (manufactured by Tosoh Co., Ltd., hydrogen bromide concentration of 47% to 49%) in terms of bromine atoms, the mass ratio of solvent / p-xylene is taken as 5.0, The reaction temperature is 190°C, the reaction pressure is 1.1MPa, and the residence time is 60 minutes. P-xylene is oxidized by air in a continuous tank reactor, and the obtained terephthalic acid slurry is subjected to vertical centrifugation. The separator (rotation number 4500rpm) is used for solid-liquid separation to obtain oxidation reaction mother liquor and terephtha...

Embodiment 2

[0065] In the stirring tank (5) equipped with a jacket for heating, continuously feed the concentrate (4) prepared in the same way as in Example 1 at 400 parts by mass per hour, and continuously feed water at 200 parts by mass per hour (6) Perform hot water treatment at 500 rpm for 40 minutes at 74°C. In the stirring tank (8), continuously feed the formed hot water slurry (7) at 600 parts by mass per hour, and continuously feed water (9) at 1800 parts by mass per hour, at 40° C. for 20 minutes at 700 rpm Granulation treatment. The post-processing of the granulated slurry was carried out in the same manner as in Example 1. As a result, the obtained granulated slurry (10) had an average particle diameter of 1.40 to 2.00 mm, and the water concentration of the separated solid residue (13) was 15%. The catalyst recovery rate of the aqueous catalyst solution (12) was found to be 93% for cobalt and manganese, and 75% for bromine. The results are shown in Table 1.

Embodiment 3

[0067] Except having changed the hot water treatment temperature in Example 2 into 88 degreeC from 74 degreeC, it processed by the method similar to Example 2, and obtained the granulated slurry (10). The obtained granulated slurry (10) has an average particle diameter of 1.40-2.00mm, and the water concentration of the separated solid residue (13) is 15%. The catalyst recovery rate of the aqueous catalyst solution (12) was found to be 94% for cobalt and manganese, and 85% for bromine. The results are shown in Table 1.

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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...

Claims

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Application Information

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IPC IPC(8): B01J38/00B01J23/90B01J38/02C07C51/265C07C63/00
CPCY02P20/584
Inventor 冨田博小里爱一郎有田恭士
Owner MITSUI CHEM INC
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