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Method for refining long-chain dibasic acid under protection of inert gas

A long-chain dibasic acid and inert gas technology, which is applied in the field of refining normal long-chain dibasic acids under the protection of inert gas, can solve the problems of high residual acetic acid, limited application range, and high solvent residue, so as to improve utilization efficiency, Improve product quality, good product quality effect

Active Publication Date: 2019-07-23
张艾琳
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The advantage of this method is that the purity of the product after refining reaches more than 98%. On the one hand, the disadvantage is that the residual acetic acid in the product is high, which limits the scope of application of the product; High solubility, low product yield
[0012]1) Use low-carbon alcohol as solvent to refine long-chain dibasic acid. At high temperature, alcohol will esterify with long-chain dibasic acid, which will affect the quality of the product quality
[0013]2) Use acetic acid as a solvent to refine long-chain dibasic acids, all of which are high-concentration acetic acid. There are many problems such as low yield of acid refining and high energy consumption for recovering high-concentration acetic acid
[0014] In summary, recrystallization of long-chain dibasic acids with organic solvent acetic acid can effectively improve product quality, but the existing methods for refining acetic acid have a high yield Low, and the disadvantages of high solvent residue in the product are also significant

Method used

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  • Method for refining long-chain dibasic acid under protection of inert gas

Examples

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Effect test

example 1

[0059] A kind of refining method of dodecanedioic acid of the present invention of example 1

[0060] Take 500kg of crude dodecanedibasic acid (loss on drying <0.5%), add 0.8% activated carbon to 2000kg of 82% acetic acid solution, stir and heat up to 84°C, and decolorize for 60 minutes. The dodecanedibasic acid solution obtained by filtration enters the crystallization tank, stirs and controls the cooling rate to drop 3-15°C per hour, and slowly cools down to 22°C. The obtained dodecanedibasic acid was filtered, resuspended by adding 3000 kg of water, and the system was heated to 120°C under the protection of an inert nitrogen gas, kept for 50 minutes, slowly cooled (by 8°C per hour) to room temperature, separated and dried to obtain twelve Carbon dibasic acid products (loss on drying not more than 1%).

example 2

[0061] Example 2 The refining method of a kind of dodecanedioic acid of the present invention

[0062] Take 500kg of crude dodecanedibasic acid (loss on drying <0.5%), add 0.6% activated carbon into 2000kg of 83% acetic acid solution, stir and heat up to 85°C, and the decolorization time is 70min. The dibasic acid solution obtained by filtration enters the crystallization tank, stirs and controls the cooling rate to drop 3-15°C per hour, and slowly cools down to crystallize in the crystallization tank to 21°C. Filtrate the obtained dodecanedibasic acid, add 3000kg of deionized water to resuspend, the system is under the protection of nitrogen inert gas, heat up to 135°C, keep warm for 60min, slowly cool down (8°C per hour) to room temperature, separate and dry Dodecanedibasic acid product (loss on drying not more than 1%) is obtained.

example 3

[0063] Example 3 The refining method of a kind of tridecanedioic acid of the present invention

[0064] Take 500kg of crude tridecanedibasic acid (loss on drying < 0.5%), add 0.7% activated carbon into 2500kg of 80% acetic acid solution, stir and heat up to 82°C, and the decolorization time is 70min. The dibasic acid solution obtained by filtration enters the crystallization tank, stirs and controls the cooling rate to drop 3-15°C per hour, and slowly cools down to crystallize in the crystallization tank to 22°C. The tridecanedibasic acid obtained by filtration was resuspended by adding 3000 kg of deionized water. Under the protection of nitrogen inert gas, the system was heated to 120°C, kept for 70 minutes, cooled (by 8°C per hour) to room temperature, separated and dried to obtain Tridecane dibasic acid product (loss on drying not more than 1%).

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Abstract

The invention provides a method for refining long-chain dibasic acid under protection of inert gas. The long-chain dibasic acid is prepared from a long-chain dibasic acid crude product prepared with abiological method as a raw material with low-concentration acetic acid as a solvent. The method specifically comprises the following steps: mixing the long-chain dibasic acid crude product and low-concentration acetic acid, performing stirring, heating and decoloration, performing filtration without thermal insulation, cooling filtrate slowly, performing crystallization and separation to obtain adibasic acid intermediate, re-suspending the intermediate with water at the temperature higher than the melting point temperature of corresponding monobasic acid under protection of the inert gas, and performing thermal insulation, cooling, separation and drying to obtain a long-chain dibasic acid refined product. The method overcomes the defects that existing solvent refining methods are low inyield and the content of solvent residues in products is high. The refined long-chain dibasic acid can completely meet the raw material quality requirement of polymer material synthesis.

Description

technical field [0001] The invention relates to a refining method and product of a normal long-chain dibasic acid under the protection of an inert gas. Specifically, it refers to recrystallizing the crude product of a long-chain dibasic acid in a low-concentration acetic acid solvent, and then using a The invention relates to a method for obtaining high-purity, crystalline long-chain dibasic acid products by resuspending them in deionized water at a temperature corresponding to the melting point of the chain-length monobasic acid, which belongs to the technical field of biochemical industry. Background technique [0002] Long-chain dibasic acid refers to a straight-chain dibasic carboxylic acid containing more than 10 carbon atoms. It is a fine chemical intermediate with important uses and is widely used in the synthesis of high-grade spices, high-performance nylon engineering plastics, high-grade lubricants, High-temperature dielectrics, high-grade paints and coatings, high...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C55/21C07C51/47C07C51/43C07C55/02
CPCC07C51/47C07C51/43C07C55/21C07C55/02
Inventor 修德恒万贺飞张耿燕
Owner 张艾琳
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