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Method of preparing metal ion less adipic acid by nitric acid oxidation of cyclohexane oxidation liquid pickling water

A technology for oxidizing cyclohexane and nitric acid is applied in directions such as oxidation to prepare carboxylic acid, which can solve the problems such as limiting the application range of adipic acid, and achieve the effects of low production cost, high purity and simple reaction process.

Inactive Publication Date: 2007-05-02
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] There are also many patents on the preparation of adipic acid from the pickling water of the cyclohexane oxidation solution by chemical methods, and the nitric acid catalytic oxidation method is the mainstream method. Due to the use of catalysts such as vanadium and copper, it is inevitable that the prepared adipic acid The acid contains metal ions, and many uses of adipic acid have very strict requirements on the concentration of metal ions, especially as raw materials for fiber synthesis, which limits the application range of adipic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Take 500mL of the pickling water of the cyclohexane oxidation solution, pass it through a φ50×400mm resin column for decolorization, and concentrate the decolorized pickling water at a pressure of 0.01-0.04MPa to obtain 105.3g of 48% organic matter content Concentrated solution, put the concentrated solution into the reaction kettle, add 60mL, 65% nitric acid to carry out the oxidation reaction under constant stirring, control the reaction temperature at 85-90°C, keep the reaction for 3h, then cool and crystallize, filter and dry to obtain crude 36.5 g of adipic acid, the purity of adipic acid is 93.0%. Crude adipic acid was dissolved in 100 mL of hot water, recrystallized, filtered, and dried to obtain 28.3 g of refined hexanoic acid with a purity of 99.6%.

Embodiment 2

[0017] Take 100g of concentrated solution of pickling water of cyclohexane oxidation solution with an organic content of 50% in the reaction kettle, add 50mL of 65% nitric acid dropwise within 50min to carry out the oxidation reaction, control the reaction temperature at 80-90°C, and keep the reaction for 2h , add 10g of activated carbon for decolorization, filter while hot, cool and crystallize the mother liquor, filter to obtain 28.3g of crude hexanoic acid, the purity of the product is 94.2%, and then dissolve the crude adipic acid in 100mL of hot water for recrystallization , to obtain 22.6g of refined adipic acid, the purity of adipic acid is 99.5%, and the product is white.

Embodiment 3

[0019] In reactor, add the nitric acid of 60mL65%, then add water and be made into 40% (mass) concentration, at 65 ℃, add dropwise organic matter content and be the hexanaphthene oxidation liquid pickling water concentrated solution 101.3g, feed rate such that No bumping in the reaction is the control standard, keep the reaction for 3.5 hours, then decolorize with 10g of activated carbon at 80°C, cool the filtered reaction solution to about 20°C, filter and dry the crystallized adipic acid to obtain 29.3g Crude adipic acid was recrystallized by adding 100 mL of water to obtain 23.8 g of refined adipic acid with a purity of 98.1%.

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PUM

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Abstract

A propress for treating hexanedioic acid without metal ions from the acidic washing water of cyclohexane oxidizing liquid by oxidizing with nitric acid includes such steps as proportionally using water to wash the cyclohexane oxidizing liquid, vacuum concentrating of acidic washing water, adding nitric acid, oxidizing reacting, crystallizing, filtering, drying and recrystallizing.

Description

technical field [0001] The invention relates to a method for preparing metal ion-free adipic acid by nitric acid oxidation of cyclohexane oxidation liquid pickling water, which belongs to the preparation technology of metal ion-free adipic acid. Background technique [0002] At present, the industrial preparation of adipic acid and caprolactam is carried out by the air oxidation of cyclohexane, first preparing cyclohexanone and cyclohexanol, due to the complexity of the air oxidation process, in addition to generating the main products cyclohexanone and cyclohexanol In addition to hexanol, about 10% of dibasic acid, monobasic acid, hydroxy acid, lactone, tar and other substances will be by-produced at the same time. These by-products are usually separated from the reaction solution by washing with water. Since most of the washings are organic acids, these washing waters are often called pickling water. [0003] For the treatment of these pickling water, the method of incine...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C55/14C07C51/16
Inventor 马沛生杨长生马友光樊丽华相正乐
Owner TIANJIN UNIV