Method for methyl esterification recovery and recycle of PTA oxidation residue

A methyl esterification and residue technology, which is applied in the field of methyl esterification recycling PTA oxidation residue, can solve the problem of not considering the impact

Inactive Publication Date: 2015-11-04
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method does not consider the impact of impurities such as PT and 4-CBA in the residue on the quality of the recovered product

Method used

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  • Method for methyl esterification recovery and recycle of PTA oxidation residue
  • Method for methyl esterification recovery and recycle of PTA oxidation residue
  • Method for methyl esterification recovery and recycle of PTA oxidation residue

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] A 1.0L high-pressure reactor was used for air oxidation treatment of PTA oxidation residue. The high-pressure reactor is equipped with electric heating and internal cooling oil coil, and the temperature is controlled by PID; the gas phase outlet of the reactor is equipped with a stop valve, a condenser, and a back pressure valve. The condensate in the condenser can return to the reactor, and the back pressure valve can Control the reaction pressure; it is also equipped with an online detection system for intake flow and tail oxygen concentration. The residue A is used as a raw material, and the residue A is first dried until the water content is less than 5.0%, and the dried residue contains 1200 ppm Co and 300 ppm Mn as measured by ICP. Quantitatively take residue A after 150.0g dry treatment, 5.0g PT acid methyl ester (PTE) and 600.0g methyl benzoate solvent and add autoclave; Pass into nitrogen in stirring process, pressurization and heat up; When pressure rises to ...

Embodiment 2

[0071] A 1.0L autoclave was used for methyl esterification of PTA oxidation residue. The autoclave used was similar to Example 1, the temperature was controlled by PID, and the gas phase outlet of the reactor was equipped with a stop valve, a condenser, a back pressure valve, etc. The difference is that the condensate in the gas phase condenser of the reactor is not directly refluxed, but recovered by a solvent tank. The residue A after the drying treatment is used as the raw material for the methyl esterification reaction, and the residue is dried and has a water content of less than 5.0%. First quantitatively weigh 250.0g of residue A and 500.0g of methanol into the autoclave; feed nitrogen during the stirring process, then close the gas phase outlet stop valve; heat up to 240°C, and the pressure in the reactor is 8.0MPa; After stirring for 3 hours, lower the temperature and lower the pressure, take a sample to measure the acid value of the reaction liquid phase, and then ca...

Embodiment 3

[0073] Carry out the methyl esterification reaction as in Example 2, the difference is that the dry residue B is used as a raw material, the reactor feed is 200.0g residue B and 600.0g methanol, the esterification temperature is 250°C, the pressure is 10.0MPa, and the esterification time for 2 hours. After the reaction was finished, by NaOH titration, the acid value of the reaction product was measured to be 105.8 mgKOH / g (calculated as residue), and the methyl esterification rate of carboxylic acid in the residue was calculated to be about 83.6%.

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Abstract

The invention discloses a method for methyl esterification recovery and recycle of PTA oxidation residue. The method comprises 1, primary oxidation treatment, 2, secondary methyl esterification treatment, and 3, tertiary rectification treatment, wherein methyl benzoate is recovered by primary reduced pressure rectification, methyl toluate is recovered by secondary reduced pressure rectification, mixed benzenedicarboxylic acid dimethyl ester is recovered by tertiary reduced pressure rectification, and dimethyl terephthalate, dimethyl isophthalate and dimethyl phthalate are respectively recovered by mixed benzenedicarboxylic acid dimethyl ester crystallization treatment. The method effectively recovers BA, IPA, TA, PT, 4-CBA, 4-HBA, OPA and TMA of the PTA oxidation residue, can produce high purity methyl benzoate, mixed benzenedicarboxylic acid dimethyl ester and trimethyl trimellitate products and realizes separation and recovery of DMT, DMI and DMO products from mixed benzenedicarboxylic acid dimethyl ester by crystallization.

Description

technical field [0001] The invention relates to an industrial technology for large-scale recovery and utilization of PTA oxidation residues by using a methyl esterification method, in particular to a method for methyl esterification recovery and utilization of PTA oxidation residues. Background technique [0002] Terephthalic acid is an important chemical raw material, mainly used in the production of polyester fibers, polyester materials, plasticizers and dyes. At present, the production of terephthalic acid adopts the catalytic oxidation method of p-xylene (US2833816, US4243636), and the obtained crude terephthalic acid (CTA) is refined to obtain a terephthalic acid product with a purity that meets the requirements. In the production process, in order to control the impurity concentration of CTA, a part of the circulating reaction mother liquor will be extracted for impurity removal and purification treatment (US4939297, CN200410067358, CN200410045270), and after recovery ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/78C07C69/76C07C69/80C07C69/82C07C67/08C07C63/26C07C67/54C07C67/52C07C67/313C07C51/215C07C51/235
CPCC07C67/313C07C51/215C07C51/235C07C67/08C07C67/52C07C67/54C07C69/78C07C69/76C07C69/82C07C63/26C07C69/80
Inventor 成有为吴春园许新望刘友志王丽军李希
Owner ZHEJIANG UNIV
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