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Method for preparing hexanedioic acid from cyclohexane oxidation byproducts

A technology of by-product, cyclohexane, applied in the field of preparing adipic acid by oxidation of cyclohexane, which can solve the problems of unfavorable implementation, large yield difference, long reaction time, etc.

Inactive Publication Date: 2012-05-23
CHINA PETROCHEM DEVMENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Said method uses hydrogen peroxide aqueous solution as oxidizing agent, although the corrosion problem derived from using nitric acid as oxidizing agent can be avoided, but because the miscibility between hydrogen peroxide and epoxycyclohexane oily substances is not good, the catalyst is in the process of oxidation. The ability of catalysis is different, and the yield of epoxycyclohexane oxidatively transforms adipic acid is relatively different, if wanting to improve the total yield often needs longer reaction time, and described method uses epoxycyclohexane compound as Raw materials, because the price of epoxycyclohexane compound and product adipic acid is equivalent, based on economic benefit considerations, it is not conducive to industrial implementation
On the other hand, for the light oil by-products of the oxidation of cyclohexane, in addition to epoxy cyclohexane, the main components also contain compounds such as various alcohols, aldehydes and ketones. If the oxidation reaction is directly carried out as a raw material, not only Increase the consumption of oxidant and its by-products are many and complex, which will increase the cost and difficulty of subsequent purification of adipic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Take 500 grams of light oil (257.4 grams of epoxycyclohexane), add 125 grams of water and 10 grams of concentrated sulfuric acid, and carry out hydrolysis reaction at 85 ° C for 3 hours. Next, use a rotary evaporator to separate and remove low-boiling components in the light oil with a boiling point lower than that of 1,2-cyclohexanediol to obtain 382 grams of crude 1,2-cyclohexanediol. Based on the total weight of the 1,2-cyclohexanediol crude product, an equal amount of water is added to form an aqueous 1,2-cyclohexanediol solution.

[0023] The 1,2-cyclohexanediol aqueous solution was poured into a 2-liter four-port glass reactor, and the reactor was equipped with a reflux condenser, a stirring device, and a temperature-sensitive control heating device. Add 6 grams of sodium phosphotungstate, while heating and stirring until the inner temperature of the reactor is 65°C, start to add 640 grams of 50% by weight hydrogen peroxide dropwise. After the dropwise addition, t...

Embodiment 2

[0025] Take 500 grams of light oil (257.4 grams of epoxycyclohexane), add 200 grams of water and 11 grams of concentrated sulfuric acid, and carry out hydrolysis reaction at 85 ° C for 4 hours. Next, a rotary evaporator was used to separate and remove low-boiling components in the light oil with a boiling point lower than that of 1,2-cyclohexanediol to obtain 348 g of crude 1,2-cyclohexanediol. Based on the total weight of the 1,2-cyclohexanediol crude product, 2 / 3 times the amount of water is added to form a 1,2-cyclohexanediol aqueous solution.

[0026] The 1,2-cyclohexanediol aqueous solution was poured into a 2-liter four-port glass reactor, and the reactor was equipped with a reflux condenser, a stirring device, and a temperature-sensitive control heating device. Add 10 grams of phosphotungstic acid, while heating and stirring until the inner temperature of the reactor is 85°C, start to drop 925 grams of 35% by weight hydrogen peroxide, after the dropwise addition, the te...

Embodiment 3

[0028] Take 500 grams of light oil (257.4 grams of epoxycyclohexane), add 200 grams of water and 11 grams of concentrated sulfuric acid, and carry out hydrolysis reaction at 85 ° C for 4 hours. Next, a rotary evaporator was used to separate and remove low-boiling components in the light oil with a boiling point lower than that of 1,2-cyclohexanediol to obtain 351 grams of crude 1,2-cyclohexanediol. Based on the total weight of the 1,2-cyclohexanediol crude product, 2 / 3 times the amount of water is added to form a 1,2-cyclohexanediol aqueous solution.

[0029] The 1,2-cyclohexanediol aqueous solution was poured into a 2-liter four-port glass reactor, and the reactor was equipped with a reflux condenser, a stirring device, and a temperature-sensitive control heating device. Add 6 grams of sodium tungstate, while heating and stirring until the inner temperature of the reactor is 85°C, start to add 640 grams of 50% by weight hydrogen peroxide dropwise. After the dropwise addition,...

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PUM

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Abstract

The invention relates to a method for preparing hexanedioic acid from cyclohexane oxidation byproducts. The method comprises the following steps: 1, hydrolyzing raw materials light oil byproducts of a cyclohexane oxidation reaction by adding water to them to make epoxycyclohexane in the light oil byproducts hydrolyze to form 1,2-cyclohexanediol; 2, carrying out primary separation to obtain crude 1,2-cyclohexanediol; 3, adding water to form an aqueous 1,2-cyclohexanediol solution; and 4, adding a catalyst and an oxidant to carry out an oxidation reaction to oxidize 1,2-cyclohexanediol in the aqueous solution into hexanedioic acid. The method which uses the cyclohexane oxidation byproducts as the raw materials can obtain hexanedioic acid in a high recovery rate within a short reaction time.

Description

technical field [0001] The invention relates to a method for producing adipic acid, in particular to a method for preparing adipic acid by utilizing cyclohexane oxidation by-products. Background technique [0002] The main products such as cyclohexanone and cyclohexanol obtained after the oxidation of cyclohexane are important raw materials for the preparation of adipic acid and caprolactam, and adipic acid and caprolactam can be further synthesized into fibers such as nylon 66 and nylon 6 respectively, which have extremely high Economic Value. [0003] The oxidation reaction of cyclohexane uses air as an oxidant to directly oxidize liquid-phase air. During the oxidation process, peroxides are formed first, and then decomposed to generate some neutral substances and acidic substances. These acidic substances will react with neutral alcohols. form esters. Therefore, in addition to the main products cyclohexanone and cyclohexanol in the oxidation reaction solution of cyclohe...

Claims

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Application Information

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IPC IPC(8): C07C55/14C07C51/31C07C51/285
Inventor 黄志达龚永顺蔡耀庆
Owner CHINA PETROCHEM DEVMENT
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