Method for preparing 2,5-dihydroxy p-benzene dicarboxylic acid

A technology of hydroxyterephthalic acid and hydroquinone, which is applied in the field of catalytic preparation 2, can solve the problems of unseen and high solvent toxicity, and achieve the effect of high yield and high purity

Inactive Publication Date: 2009-08-19
JIANGSU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The synthesis reaction of 2,5-dihydroxyterephthalic acid belongs to the Kolbe-Schmitt reaction. In its preparation process, in order to alleviate the shortcomings of reaction materials agglomeration and sticking to the wall of the kettle, short reaction time, high conversion rate and yield, domestic and foreign Researchers often use xylene as a solvent, but there is a disadvantage of high solvent toxicity
Furthermore, few have applied catalysts to the Kolbe-Schmitt carboxylation process
Schmeling, Narmandakh etc. in "Journal of Bacteriology" 2004 No. 23 article "Phenylphosphate synthase: a new phosphotransferase catalyzing the first step in anaerobic phenol metabolism in Thauera aromatica" and 2006 22 article "Phosphorylation of phenol byphenylphosphate of lephine rosyn "catalysis" studied the anaerobic metabolism of phenol in enzyme-catalyzed denitrifying bacteria (also known as biological Kolbe-Schmitt reaction); other researchers reported that Pd(II) catalyzed benzyl chloride, biphenyl, anisole, furan, Carboxylation reactions of compounds such as thiophene, such as the article "Synthesis of 2-arylpropionic acids by electrocarboxylation of benzylchloridescatalysed by PdCl" published by Damodar et al. in the 12th issue of "Electrochemistry Communications" in 2001 2 (PPh 3 ) 2 "Reported the carboxylation reaction of benzyl chloride catalyzed by Pd(II). Yamada et al. reported that Pd (II) Catalyzed biphenyl carboxylation reaction, but there is no report using n-octane as a solvent to catalyze hydroquinone with a catalyst to obtain 2,5-dihydroxyterephthalic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0018] In a 0.5L autoclave with heating, stirring and temperature control system, add 13.75g hydroquinone, 35g potassium hydroxide, 150ml n-octane and 5% Pd(II) / C catalyst. Introduce carbon dioxide gas, raise the temperature to 200°C, make the pressure of the kettle reach 9.5MPa, and react for 4 hours. Cool the reacted mixture, suction filter, recover the filtrate, dissolve the filter cake in 500ml of 0.1% sodium bisulfite aqueous solution, heat and boil to remove the residual solvent, and suction filter while the mixture is fully dissolved Remove a little impurity and catalyst, cool the filtrate in an ice-water bath to below 8°C to crystallize, and wash the filter cake with a small amount of ice water. After the obtained filter cake was dissolved in 300ml of hot water, concentrated hydrochloric acid was added to adjust the pH to less than 2, and after stirring, it was allowed to stand for 1 hour, then suction filtered, the filter cake was washed, and the filter cake was vacu...

example 2

[0020] In a 0.5L autoclave with heating, stirring and temperature control system, add 13.75g hydroquinone, 35g potassium hydroxide, 150ml n-octane and 5% Pd(II) / C catalyst. Introduce carbon dioxide gas, raise the temperature to 200°C, make the pressure of the kettle reach 11.5MPa, and react for 4 hours. Cool the reacted mixture, suction filter, recover the filtrate, dissolve the filter cake in 500ml of 0.1% sodium bisulfite aqueous solution, heat and boil to remove the residual solvent, and suction filter while the mixture is fully dissolved Remove a little impurity and catalyst, cool the filtrate in an ice-water bath to below 8°C to crystallize, and wash the filter cake with a small amount of ice water. After the obtained filter cake was dissolved in 300ml of hot water, concentrated hydrochloric acid was added to adjust the pH to less than 2, and after stirring, it was allowed to stand for 1 hour, then suction filtered, the filter cake was washed, and the filter cake was vac...

example 3

[0022] In a 0.5L autoclave with heating, stirring and temperature control system, add 13.75g hydroquinone, 35g potassium hydroxide, 150ml n-octane and 5% Pd(II) / C catalyst. Introduce carbon dioxide gas, raise the temperature to 220°C, make the pressure of the kettle reach 9.5MPa, and react for 4 hours. Cool the reacted mixture, suction filter, recover the filtrate, dissolve the filter cake in 500ml of 0.1% sodium bisulfite aqueous solution, heat and boil to remove the residual solvent, and suction filter while the mixture is fully dissolved Remove a little impurity and catalyst, cool the filtrate in an ice-water bath to below 8°C to crystallize, and wash the filter cake with a small amount of ice water. After the obtained filter cake was dissolved in 300ml of hot water, concentrated hydrochloric acid was added to adjust the pH to less than 2, and after stirring, it was allowed to stand for 1 hour, then suction filtered, the filter cake was washed, and the filter cake was vacu...

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PUM

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Abstract

A method for the carboxylation preparation of 2,5-dihydroxyterephthalic acid by taking n-octane as solvent to Pd(II) / C-catalyze the hydroquinone is disclosed, specifically comprising the steps of: in a high-pressure reaction kettle, taking sodium phenolate, potassium hydroxide and carbon dioxide as reactants, performing Pd(II) / C-catalysis to prepare 2,5-dihydroxyterephthalic acid sylvite, and obtaining the 2,5-dihydroxyterephthalic acid by means of recrystallization and acidification. The inventive catalyst is simply prepared, the solvent is easy for recovery and the product is high in purity.

Description

technical field [0001] The invention relates to a method for catalytically preparing 2,5-dihydroxyterephthalic acid, specifically referring to using n-octane as a solvent and using Pd(II) / C as a catalyst to catalyze hydroquinone, potassium hydroxide and carbon dioxide After oxidation reaction, 2,5-dihydroxyterephthalic acid is prepared by acidification. Background technique [0002] 2,5-Dihydroxyterephthalic acid is an important intermediate in organic synthesis, which can be used to synthesize polymers, complexes, colorants and fluorescent substances. The mixture of 2,5-dihydroxyterephthalic acid and terephthalic acid can be reacted with ethylene glycol to produce shaped polyester or copolyether with fiber and film-forming properties. 2,5-diamino-1,4-benzenedithiol undergoes non-homopolymerization in polyphosphoric acid to generate high-molecular-weight linear polyesters and copolymers, and 2,3,5,6-tetraaminopyridine (TAP) It can be directly polymerized into M5 polymer wi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C65/05C07C51/15B01J23/44
CPCY02P20/52
Inventor 沈玉堂漆琳殷恒波姜廷顺
Owner JIANGSU UNIV
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