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Method for producing terephthalic acid and terephthalic acid

A technology of terephthalic acid and its manufacturing method, which is applied in the preparation of carboxylate, chemical instruments and methods, and the preparation of organic compounds, and can solve problems such as increased reaction time, residual terephthalic acid, and increased by-products

Active Publication Date: 2006-09-13
MITSUI CHEM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Conversely, if the proportion of large-diameter particles exceeding 250 μm is excessively increased, terephthalic acid tends to remain as an unreacted component during the direct polymerization method. wait, it's clear
On the other hand, if the proportion of the fine powder below 50 μm is increased too much, there is a problem that it takes time to load and unload the product or transport it.

Method used

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  • Method for producing terephthalic acid and terephthalic acid
  • Method for producing terephthalic acid and terephthalic acid
  • Method for producing terephthalic acid and terephthalic acid

Examples

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Embodiment 1

[0060] The inventors of the present invention will specifically describe experiments performed during continuous operation with respect to the former conventional manufacturing apparatus described above and the manufacturing apparatus according to the third embodiment of the present invention.

[0061] Adjust the water slurry of high-purity terephthalic acid with a particle size distribution of 74 to 149 μm, pressurize the slurry in a dissolution tank, and completely dissolve the aqueous solution of terephthalic acid at 220°C, use 3 series crystallization tank for crystallization.

[0062] In this case, when the inner diameter of the first crystallization tank is D and the blade diameter is R, the blade diameter R by stirring is 0.5D, and the shape of the blade is such that the length in the vertical direction on the central part side is 0.5R, and the length of the front end of the blade in the vertical direction is 0.15R. The stirring blade is composed of 6 blades. The ratio...

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Abstract

A method for producing terephthalic acid wherein an aqueous terephthalic acid solution is purified with a platinum group metal catalyst and then terephthalic acid is crystallized from the resultant aqueous solution, which comprises carrying out the crystallization in an agitating vessel which has, in the bottom portion thereof, an agitating blade being formed in a shape of an approximately trapezoidal plate and being capable of changing a rotating number; and a terephthalic acid product having a narrow particle size distribution. The above method allows the production with good efficiency of terephthalic acid crystals which are excellent in powder characteristics, slurry characteristics and reactivity, and can be controlled with respect to the particle size distribution.

Description

technical field [0001] The present invention relates to a method for producing terephthalic acid, and more specifically, to a method for producing terephthalic acid suitable as a raw material for producing polyester such as polyethylene terephthalate. The present invention also relates to terephthalic acid having a narrow particle size distribution produced by the production method. Background technique [0002] The crude terephthalic acid obtained by the oxidation of p-xylene usually contains a lot of various impurities such as 4-carboxybenzaldehyde (abbreviated as "4CBA"). raw materials to use. [0003] As a method for purifying such crude terephthalic acid, a method of dissolving crude terephthalic acid in an aqueous solvent, bringing it into contact with a platinum group metal catalyst under high pressure and high temperature to perform purification is known (for example, Kaiping No. 6-329583), several refining methods are also known. [0004] As an oxidation reaction...

Claims

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Application Information

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IPC IPC(8): C07C51/43C07C63/26C07C51/487
CPCC07C51/487C07C51/43C07C63/26B01D9/0059B01J23/40C07C2523/40
Inventor 加藤一彦
Owner MITSUI CHEM INC
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