Method for producing high-purity terephthalic acid
A technology of terephthalic acid and crude terephthalic acid, which is applied in the separation/purification of carboxylic acid compounds, organic chemistry and other directions, and can solve the problems of increasing the amount of solid matter and increasing the size of the device.
Active Publication Date: 2011-06-22
MITSUBISHI RAYON CO LTD
View PDF3 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
When the cleaning liquid j containing the solid matter is reused as the solvent in the slurry tank 1 without any treatment, the amount of solid matter treated in the purification step system increases, but this results in the necessity of enlarging each device size to keep the slurry concentration constant in the system
In addition, when solid-liquid separation and cleaning operations are performed in an integrated device under high temperature and high pressure, the amount of terephthalic acid dissolved in the cleaning effluent increases, which also leads to an increase in the amount of solids in the system, so It is necessary to increase the size of the device
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment
[0103] An acetic acid solution containing p-xylene and a catalyst (acetic acid solutions of cobalt acetate and manganese acetate and hydrogen bromide), separated mother liquor recovered from a subsequent solid-liquid separation step, and air were continuously supplied to the stirring tank. The oxidation reaction was carried out simultaneously under the condition that the operating temperature was 190° C., the operating pressure was 1.23 MPa (absolute pressure), and the liquid level was controlled so that the residence time was 1 hour. In addition, the distilled vapor was cooled to a final temperature of 40° C. using a condenser arranged in multiple stages. The apparatus was operated with the vent gas controlled so that the concentration of oxygen was 2.5% by volume. In addition, condensates obtained through the respective condensers were mixed and refluxed into the oxidation reactor, and part of the condensates were discharged so that the mother liquor in the slurry discharged...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
A method for producing high purity terephthalic acid having a step (a) of forming crude terephthalic acid, a dissolution step (b) of dissolving the crude terephthalic acid in a water solvent, a reduction step(c), a crystallization step (d), a separation step (e), a washing step (f) and a drying step (g), which further comprises a recovering step (h) wherein a solid contained in the washing wastewater discharged from the above washing step (f) is recovered and the resultant solid is fed to the above crystallization step (d) or to the above separation step (e), and a reuse step (i) wherein the washing wastewater having been subjected to the recovery of a solid in the above recovering step (h) is used as a solvent for the above dissolution step (b). The above method allows the reuse of a washing wastewater with an apparatus being compact in size, in the production of high purity terephthalic acid.
Description
technical field [0001] The present invention relates to a method for producing high-purity terephthalic acid. Background technique [0002] In order to obtain crystals of high-purity terephthalic acid, it is necessary to remove as much as possible intermediate products, which are by-products generated when p-xylene is oxidized, from crude terephthalic acid crystals obtained by oxidizing p-xylene, and Contains 4-carboxybenzaldehyde as a main component (this intermediate product is an effective component that can be converted to terephthalic acid, but becomes an impurity after mixing with the product terephthalic acid). In view of this, a purification step is performed in which 4-carboxybenzaldehyde is reduced to p-toluic acid, which is more water-soluble than terephthalic acid, and then terephthalic acid is crystallized to obtain high-purity terephthalic acid crystals. This process includes, for example, figure 2 The following steps shown in . [0003] First, in the dissol...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/43C07C63/26
CPCC07C51/43
Inventor 沼田元幹矶贝隆行绪方知彦
Owner MITSUBISHI RAYON CO LTD