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Recovery method of nylon acid

A technology of nylon acid and glutaric acid, which is applied in the separation/purification of carboxylic acid compounds, organic chemistry, etc., can solve the problem of low purity of glutaric acid, and achieve the effect of improving comprehensive benefits and simple and efficient process

Inactive Publication Date: 2018-05-08
中国平煤神马控股集团有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for recycling nylon acid, so that the added value of nylon acid can be greatly improved, which not only solves the problem of low purity of glutaric acid products separated by existing methods, but also, according to market conditions, Value-based use of these isolates to obtain high value-added products to maximize the value of nylon acid recovery

Method used

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  • Recovery method of nylon acid
  • Recovery method of nylon acid

Examples

Experimental program
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Effect test

Embodiment 1

[0035] The recycling method of the nylon acid of the present embodiment, the system that adopts is as figure 1 shown, including the following steps:

[0036] 1) Nylon acid knot sheet (in nylon acid knot sheet, the mass content of succinic acid, glutaric acid, adipic acid is respectively 23%, 65%, 12%) and water are mixed by mass ratio 4:1, in After heating and dissolving at 80°C, cool down to 30°C in the primary crystallizer, stir and crystallize for 7 hours at a stirring rate of 400rpm, and then pump into centrifuge S for centrifugal separation to obtain primary crystals and primary mother liquor;

[0037]2) Remove 15wt% of the water in the primary mother liquor through the tube pass, send it to the first glutaric acid crystallizer, stir and crystallize at 20°C for 4h, the stirring rate is 400rpm, and centrifuge after the crystallization to obtain the crude product Glutaric acid and secondary mother liquor;

[0038] The primary crystal is dissolved in water in the first mix...

Embodiment 2

[0044] The recycling method of the nylon acid of the present embodiment, process flow chart is as figure 1 shown, including the following steps:

[0045] 1) Nylon acid knot sheet (in nylon acid knot sheet, the mass content of succinic acid, glutaric acid, adipic acid is respectively 23%, 65%, 12%) and water are mixed by mass ratio 5:1, in After heating and dissolving at 80°C, cool down to 35°C in the primary crystallizer, stir and crystallize for 5 hours at a stirring rate of 600rpm, and then pump into centrifuge S for centrifugal separation to obtain primary crystals and primary mother liquor;

[0046] 2) Remove 10wt% of the water in the primary mother liquor through the tube pass, send it to the first glutaric acid crystallizer, stir and crystallize at 25°C for 6h, the stirring rate is 600rpm, and perform centrifugation after the crystallization is completed to obtain the crude product Glutaric acid and secondary mother liquor;

[0047] The primary crystal is dissolved in ...

Embodiment 3

[0053] The recycling method of the nylon acid of the present embodiment, process flow chart is as figure 1 shown, including the following steps:

[0054] 1) Nylon acid knot sheet (in nylon acid knot sheet, the mass content of succinic acid, glutaric acid, adipic acid is respectively 23%, 65%, 12%) and water are mixed by mass ratio 1.5:1, in After heating and dissolving at 80°C, cool down to 20°C in the primary crystallizer, stir and crystallize for 4 hours at a stirring rate of 200rpm, and then pump into centrifuge S for centrifugal separation to obtain primary crystals and primary mother liquor;

[0055] 2) Remove 20wt% of the water in the primary mother liquor through the tube pass, send it to the first glutaric acid crystallizer, stir and crystallize at 10°C for 2 hours, the stirring rate is 200rpm, and centrifuge after the crystallization is completed to obtain the crude product Glutaric acid and secondary mother liquor;

[0056] The primary crystal is dissolved in water...

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Abstract

The invention relates to a recovery method of nylon acid. The recovery method of nylon acid comprises following steps: 1, nylon acid is dissolved in water, an obtained solution is cooled to 20 to 35 DEG C for crystallization, and separation is carried out so as to obtain a primary mother liquor; 2, the primary mother liquor is subjected to condensation, is subjected to crystallization at 10 to 25DEG C, and is subjected to separation so as to obtain crude glutaric acid. The obtained crude glutaric acid is subjected to recrystallization, and then is reacted with hexylenediamine so as to preparenylon 65, and crystals obtained via primary crystallization can be reacted with butylene glycol to prepare mixed polyester polyols. According to the recovery method, only one time of crystallizationis adopted in preparation of crude glutaric acid, the content of glutaric acid in obtained primary crystals is low, the glutaric acid concentration in obtained primary mother liquor is high; condensation of primary mother liquor is capable of breaking the dissolving-crystallization balance of the primary mother liquor, and increase the crystallization potential energy of glutaric acid; then cooling crystallization is adopted to prepare crude glutaric acid with a purity ranging from 93 to 98%; and then recrystallization of the obtained crude glutaric acid is carried out so as to obtain high purity glutaric acid with a purity of 99.9% or higher.

Description

technical field [0001] The invention belongs to the field of separation and purification of nylon acid, and in particular relates to a method for recycling nylon acid. Background technique [0002] In the process of producing adipic acid (ADA) by nitric acid oxidation with cyclohexanol as raw material, two other dibasic acids: succinic acid (SA) and glutaric acid (GA) will be produced simultaneously. This production process is accompanied by a large amount of Nylon acid (glutaric acid, succinic acid, adipic acid) wastewater is produced. The composition of nylon acid wastewater is about: 3wt% adipic acid, 15wt% glutaric acid, 6wt% succinic acid, 1-3wt% nitric acid; that is, the content of nylon acid in the wastewater is about 24%. Since adipic acid, glutaric acid, and succinic acid in nylon acid (DBA) wastewater are important chemical raw materials, most companies have abandoned the previous incineration treatment method and instead use nylon acid wastewater to produce nylon...

Claims

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Application Information

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IPC IPC(8): C07C51/43C07C55/12C07C55/10C07C55/14C08G69/26C08G69/28C08G63/16
CPCC07C51/43C08G63/16C08G69/26C08G69/28C07C55/12C07C55/10C07C55/14
Inventor 赵海鹏张烨刘伟赵亚奇张罡董英英张秀欣宋远飞
Owner 中国平煤神马控股集团有限公司
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