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Method for crystallizing long-chain dicarboxylic acid and method for purifying long-chain dicarboxylic acid

A long-chain dicarboxylic acid and refining method technology, applied in the field of long-chain dicarboxylic acid refining, can solve problems such as inability to induce crystallization, lower production efficiency, and uncertain operation of crystallization control

Pending Publication Date: 2022-07-01
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this operation process is difficult to carry out effectively, because seed crystal is fine powder, when adding seed crystal to the crystallization tank that is to be crystallized with high-temperature acetic acid and is slightly positive pressure, the powder crystal seed is easily absorbed by the acetic acid vapor of positive pressure. Blowing out, and the powder seeds are easily wetted and agglomerated by acetic acid to block the feeding port, which brings uncertainty and operational danger to crystallization control
[0005] In the above-mentioned acetic acid as a solvent recrystallization and refining long-chain dicarboxylic acid disclosed patent on crystallization process control, only within a wide temperature range, add seed crystals, or do not add crystal seeds, then keep warm, and then directly cool or separate Crystallization is carried out by cooling down in stages, and no easy-to-implement and more precise crystallization control method has been proposed, which is detrimental to the repeatability and reproducibility of the production process and product quality
Those skilled in the art know that crystallization process control is a key technology for refining long-chain dicarboxylic acids with acetic acid solvents. In order to obtain an ideal crystallization state, it is necessary to add seed crystals at the right time, that is, when the long-chain dicarboxylic acids in the acetic acid solution reach Add seed crystals when supersaturated, if added too early, the seed crystals will dissolve and fail to induce crystallization, and if added too late, the system will easily explode a large number of crystal nuclei, causing fine crystals to form coalescence, forming needle-like or flaky crystals , thus affecting product purity and the subsequent filtration and drying process
In large-scale production, adding seeds to control the crystallization process is difficult to operate, requiring accurate metering of solvents and solutes, and requiring expensive testing equipment to analyze and judge the timing of adding seeds, which not only increases costs, but also reduces productivity
The crystallization method without seed crystals is obviously unfavorable for large-scale production

Method used

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  • Method for crystallizing long-chain dicarboxylic acid and method for purifying long-chain dicarboxylic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] 1, the fermented liquid containing decanedicarboxylic acid is filtered to remove solid impurities such as thalline;

[0047] II, in the product of I, add sulfuric acid, make dodecanedicarboxylic acid to separate out, filter to obtain dodecanedicarboxylic acid filter cake crude product;

[0048] III. In a 100L dissolving kettle, drop into 50 liters of acetic acid, drop into 25kg of crude dodecanedicarboxylic acid, be warming up to 84° C., heat preservation and stirring to fully dissolve the dibasic acid, and the solution enters the decolorization kettle after being clarified by a 0.1 μm aperture filter. Activated carbon 0.28kg was added to the decolorization kettle, stirred evenly, adsorbed at 82°C for 30 minutes, the decolorization solution passed through 10 μm and 0.2 μm filters in turn, and the dodecanedicarboxylic acid solution entered the crystallization kettle.

[0049] Ⅳ. Turn on the cooling system of the crystallization kettle, cool the solution to be crystallize...

Embodiment 2

[0052] 1. The fermentation broth containing dodecanedicarboxylic acid is filtered, and solid impurities such as bacterial cells are removed;

[0053] II, in the product of I, add sulfuric acid, make dodecanedicarboxylic acid to separate out, filter to obtain dodecanedicarboxylic acid filter cake crude product;

[0054] III. In a 100L dissolving kettle, drop into 58 liters of acetic acid, drop into 26 kg of dodecanedicarboxylic acid crude product, be warming up to 86° C., heat preservation and stirring to fully dissolve the dibasic acid, and the solution enters the decolorizing kettle after being clarified by a 0.1 μm aperture filter. Add 0.39kg of activated carbon to the decolorization kettle, stir evenly, absorb at 83°C for 30 minutes, the decolorization solution passes through 10 μm and 0.2 μm filters in turn, and the dodecanedicarboxylic acid solution enters the crystallization kettle.

[0055] Ⅳ. Turn on the cooling system of the crystallization kettle, cool the solution t...

Embodiment 3

[0058] 1, by filtering the fermentation broth containing tridecanedicarboxylic acid, remove solid impurities such as thalline;

[0059] II, in the product of I, add sulfuric acid, make tridecanedicarboxylic acid to separate out, filter to obtain tridecanedicarboxylic acid filter cake crude product;

[0060] III. In a 100L dissolving kettle, drop into 55 liters of acetic acid, drop into 24 kg of tridecanedicarboxylic acid crude product, be warming up to 84° C., heat preservation and stirring to fully dissolve the dibasic acid, and the solution enters the decolorizing kettle after being clarified by a 0.1 μm aperture filter. Add 0.30kg of activated carbon to the decolorization kettle, stir evenly, adsorb at 80°C for 30 minutes, the decolorization solution passes through 10 μm and 0.2 μm filters in turn, and the tridecanedicarboxylic acid solution enters the crystallization kettle.

[0061] Ⅳ. Turn on the cooling system of the crystallization kettle, cool the solution to be cryst...

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Abstract

The invention provides a crystallization method and a refining method of long-chain dicarboxylic acid, and the crystallization process is as follows: when an acetic acid solution in which long-chain dicarboxylic acid is dissolved is cooled to not lower than 75 DEG C, preferably 75-85 DEG C, a crystallization temperature control facility is closed, ice or an ice-water mixture is added into the solution system at a constant speed, the cooling speed of the solution is controlled to be 0.2-1 DEG C / min, and the temperature of the solution is controlled to be 30-60 DEG C / min; in the process of continuously adding the ice or the ice-water mixture, stopping adding the ice or the ice-water mixture when the change of the front-back cooling speed is greater than or equal to 0.1 DEG C / min, keeping the temperature, and continuously cooling to crystallize the long-chain dicarboxylic acid. The solubility of the long-chain dicarboxylic acid is reduced in a mode of feeding ice or an ice-water mixture, local cooling stimulates a solution system to form dicarboxylic acid microcrystals, large and uniform granular but not needle-shaped long-chain dicarboxylic acid crystals are obtained by combining temperature control, the crystallization method is applied to a refining process, separation is facilitated, and the purity of the long-chain dicarboxylic acid is improved. And long-chain dicarboxylic acid with better properties can be easily obtained.

Description

technical field [0001] The present invention relates to a method for crystallization of long-chain dicarboxylic acids, especially a method for crystallization of long-chain dicarboxylic acids dissolved in acetic acid, and a method for purifying long-chain dicarboxylic acids including this crystallization method. Background technique [0002] Long-chain dicarboxylic acid is an important monomer raw material for synthesizing polymers such as high-performance engineering plastics and high-grade hot melt adhesives because of its two terminal carboxyl groups. [0003] Long-chain dicarboxylic acids are metabolites of microbial fermentation. The composition of the fermentation broth is complex, including organic and inorganic substances such as microbial cells, cell debris, culture medium, proteins, amino acids, sugars, nucleic acids, lipids, etc. The type and content of impurities change continuously with time and conditions, which are all refined to obtain polymer grades. Produc...

Claims

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Application Information

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IPC IPC(8): C07C51/42C07C51/43C07C51/47C07C55/02C07C55/21C07C55/18C07C55/20
CPCC07C51/42C07C51/43C07C51/47C07C55/02C07C55/21C07C55/18C07C55/20
Inventor 高大成朱化雷王鹏翔
Owner CHINA PETROLEUM & CHEM CORP
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