Refining method of long chain dicarboxylic acid

The technology of a long-chain dibasic acid and a refining method is applied in the refining field of normal long-chain dibasic acid, can solve the problems of high acetic acid residue, high solvent residue and high energy consumption of acetic acid, and achieves improved refining yield and improved utilization efficiency , the effect of simple preparation steps

Active Publication Date: 2019-07-12
张艾琳
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  • 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
[0011]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
[0012]2) Use acetic acid as a solvent to refine long-chain dibasic acids, all of which are high-concentration acetic acid, which has high residual acetic acid in the product and long-chain dibasic There are many problems such as low yield of acid refining and high energy consumption for recovering high-concentration acetic acid
[0013] 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, high solvent residues in the product and other shortcomings are also very significant, affecting the quality of downstream customers' products

Method used

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  • Refining method of long chain dicarboxylic acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] The refining method of the dodecanedioic acid of embodiment 1 present invention

[0060] Take 500kg of crude dodecanedibasic acid (loss on drying <0.5%), add 0.8% activated carbon into 2000kg of acetic acid solution with a concentration of 82%, stir and heat up to 80°C under negative pressure (680 mm Hg), and heat up for 60 minutes for decolorization . The dodecanedibasic acid solution obtained by filtration enters the crystallization tank, stirs and controls the cooling rate to drop by 3-15°C per hour, and slowly cools down to 22°C. The obtained dodecanedibasic acid was filtered, resuspended by adding 3000kg of water, the system was heated to 80°C under a negative pressure environment (700mm Hg), kept for 50min, and slowly cooled (by 8°C per hour) to room temperature, separated, Dry to obtain dodecanedibasic acid product (loss on drying is not more than 1%).

Embodiment 2

[0061] The refining method of the dodecanedioic acid of embodiment 2 of the present invention

[0062] Take 500kg of dodecanedibasic acid crude product (loss on drying <0.5%), add 0.6% activated carbon into 2000kg of acetic acid solution with a concentration of 83%, stir and heat up to 85°C under negative pressure (720mm Hg) 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. The dodecanedibasic acid obtained by filtration was resuspended with 3000 kg of deionized water. The system was heated to 60° C. under negative pressure (720 mm Hg), kept at a temperature of 60 minutes, and slowly cooled (by 7° C. per hour) to At room temperature, separate and dry to obtain a dodecanedibasic acid product (loss on drying is not more than 1%).

Embodiment 3

[0063] The refining method of embodiment 3 tridecanedioic acid of the present invention

[0064] Take 500kg of tridecanedibasic acid crude product (loss on drying <0.5%), add 0.7% activated carbon into 2500kg of 80% acetic acid solution, stir and heat up to 82°C under negative pressure environment (750mm Hg), heat up and decolorize The time is 70 minutes. 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. Filter the tridecanedibasic acid, add 3000kg of deionized water to resuspend, heat the system to 55°C under a negative pressure environment (750mm Hg), keep it warm for 70min, and cool down (by 6°C per hour) to room temperature , separated and dried to obtain tridecanedibasic acid product (loss on drying is not more than 1%).

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Abstract

The invention provides a refining method of long chain dicarboxylic acid. The long chain dicarboxylic acid is refined with a long chain dicarboxylic acid crude product prepared with a biological method as a raw material and low-concentration acetic acid as a solvent. Specifically, the long chain dicarboxylic acid crude product and the low-concentration acetic acid are mixed firstly, stirred, heated and decolorized in a normal pressure environment, filtration is performed with thermal insulation, filtrate is cooled slowly, crystallization and separation are performed, a dicarboxylic acid intermediate is obtained and suspended with water with melting point temperature higher than that of monoacid with chain length corresponding to that of the long chain dicarboxylic acid, thermal insulation,cooling, separation and drying are performed in a negative pressure environment, and a long chain dicarboxylic acid refined product is obtained. The defects that existing solvent refining methods arelow in yield and the content of solvent residues in products is high are overcome. The refined long chain dicarboxylic acid completely meets the raw material quality requirement of polymer material synthesis.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a new method for refining normal long-chain dibasic acids. 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-grade hot-melt adhesives, cold-resistant plasticizers, precious Chinese patent medicines and other products. [0003] At present, there are mainly two methods for producing long-chain dibasic acids: chemical synthesis and microbial fermentation. Foreign countries mainly use chemical synthesis, while domestic almost all use microbial fermentation. The disadvantages of the chemical synthesis method are complex process, harsh s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/42C07C51/47C07C55/21C07C55/02
CPCC07C51/42C07C51/47C07C55/21C07C55/02
Inventor 修德恒万贺飞张耿燕
Owner 张艾琳
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