Process for producing aromatic polycarboxylic acid

a technology of aromatic polycarboxylic acid and process, which is applied in the preparation of carboxylic compounds, physical/chemical process catalysts, organic chemistry, etc., can solve the problems of complex operation, reaction is not readily advanced, and catalyst activity degrades

Inactive Publication Date: 2002-02-07
MITSUBISHI GAS CHEM CO INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

0030] After the completion of oxidation, the reaction liquid is subjected to known purifying treatments such as filtration and distillation, whereby trimellitic acid or pyromellitic acid can be obtained as a product.
0031] The present invention will be described in more detail below, referring to Examples and Comparative Examples, which are not intended to limit the scope of the present invention.
0032] The organic bromine compound concentration described in Examples and Comparative Examples was converted into a bromine concentration. That is, a bromine content in an organic bromine compound, i.e., a bromine conversion concentration was determined by subtraction of a bromine ion concentration from total bromine concentration in a reaction l

Problems solved by technology

In contrast, oxidation of psuedocumene has a defect that the metal catalyst forms a salt with trimellitic acid of a product to deposit, so that activity of the catalyst is degraded and the reaction does not readily progress.
The process for producing trimellitic acid disclosed in Japanese Patent No. 2939346 comprising air-oxidizing psuedocumene in an acetic acid solvent has defects that the operation is complicated since it is necessary to control carefully and change a temperature and a water concentration in the reaction liquid; a high price catalysts such as cobalt zirconium and cerium are used; the

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0034] Example 1

[0035] A catalyst liquid of bromine ion concentration 2.3% by weight and manganese ion concentration 0.39% by weight mixed 1452 g of water, 17.5 g of 100% hydrogen bromide and 30.5 g of manganese bromide (tetrahydrate) was charged to the first stage reactor in a continuous two stage type reactor, connected two zirconium autoclaves of inner capacity 2 L equipped with a reflux condenser, a stirrer, a heater, a raw material feeding port, a gas introducing port and reaction product withdrawing port and 1000 g of the catalyst liquid having the same components as in the first stage reactor was charged to the second stage reactor. Nitrogen was fed under an applied pressure via the gas introducing port to elevate the interior pressure of the first stage reactor up to 1 MPa and the interior temperature of the first and second stage reactors was elevated up to 220 .degree. C. with the heater. Then, each 2,4-dimethyl benzaldehyde at the rate of 200 g / hr and the catalyst liquid ...

example 2

[0040] Example 2

[0041] The oxidation of 2,4-dimethyl benzaldehyde was continuously performed in the same manner as in Example 1 except that the catalyst liquid to be charged to each reactor and to be fed to the first stage reactor was changed to a catalyst liquid of hydrogen bromide concentration 1.4% by weight and manganese ion concentration 0.39% by weight mixed 1465.5 g of water, 4.0 g of 100% hydrogen bromide and 30.5 g of manganese bromide (tetrahydrate) and the amount of the catalyst liquid to be fed to the second stage reactor was changed to 90 g / hr. The amount of bromine ion fed to the second stage occupied 22.2% of total amount of fed bromine ion. The result was shown in Table 1.

example 3

[0042] Example 3

[0043] The oxidation of 2,4-dimethyl benzaldehyde was continuously performed in the same manner as in Example 1 except that the catalyst liquid to be charged to each reactor and to be fed to the first stage reactor was changed to a catalyst liquid of hydrogen bromide concentration 2.0% by weight and manganese ion concentration 0.39% by weight mixed 1456.5 g of water, 13.0 g of 100% hydrogen bromide and 30.5 g of manganese bromide (tetrahydrate) and the amount of the catalyst liquid to be fed to the second stage reactor was changed to 120 g / hr. The amount of bromine ion fed to the second stage occupied 21.1 % of total amount of fed bromine ion. The result was shown in Table 1.

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Abstract

A process for producing a polycarboxylic acid which comprises performing liquid phase oxidation of polyalkyl-substituted aromatic aldehyde and/or oxide derivative of polyalkyl-substituted aromatic aldehyde as raw material for oxidation with molecular oxygen at two stages in water solvent in the presence of a catalyst comprising bromine or both bromine and a heavy metal(s) at a temperature of 180 to 280 ° C., thereby producing trimellitic acid or pyromellitic acid, wherein said liquid phase oxidation is performed in a continuous operation at the first stage and in a continuous operation or in a batch operation at the second stage and a total amount of bromine in said catalyst is divided to add separately at each the first stage and the second stage.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to a process for producing an aromatic polycarboxylic acid by liquid phase oxidation of polyalkyl-substituted aromatic aldehyde and / or oxide derivative thereof, and specifically, to process for producing trimellitic acid or pyromellitic acid.[0003] 2. Prior Art[0004] As industrial processes for producing trimellitic acid, a process comprising air-oxidizing psuedocumene as a raw material in an acetic acid solvent in the presence of a cobalt-manganese-bromine catalyst and a process comprising air-oxidizing 2,4-dimethyl benzaldehyde, 2,5-dimethyl benzaldehyde and 3,4-dimethyl benzaldehyde or 2,4-dimethyl benzoic acid, 2,5-dimethyl benzoic acid and 3,4-dimethyl benzoic acid of oxide derivative thereof as raw materials in water solvent in the presence of a catalyst containing bromine and manganese or cerium are widely known. As industrial processes for producing pyromellitic acid, a process comprising air-oxidizing dure...

Claims

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Application Information

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IPC IPC(8): B01J27/128B01J27/08C07B61/00C07C51/235C07C51/265C07C63/307C07C63/313
CPCC07C51/235C07C63/307
Inventor OKOSHI, ATSUSHIURABE, ETSUOYABUNO, MASASHIOGAWA, HIROSHITANAKA, KAZUO
Owner MITSUBISHI GAS CHEM CO INC
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