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Method for producing adipic acid, hexamethylenediamine sulfate and polyhexamethylene (di)guanidine sulfate from nylon-66 through depolymerization

A technology of polyhexamethylene biguanide and polyhexamethylene monoguanidine, which is applied in the field of disinfectant polyhexamethylene monoguanidine sulfate, can solve the problem of difficult separation of hexamethylenediamine, the depolymerization product, easy corrosion of equipment, Short service life and other problems, to achieve the effect of low volatility, lower requirements for production equipment, and lower production costs

Inactive Publication Date: 2013-04-17
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The technical problem to be solved by the present invention is that the depolymerization product hexamethylenediamine is difficult to separate, the purity is low, and the recovery rate is small for the current depolymerization of waste nylon-66, and the equipment in the depolymerization of nylon-66 is easy to be corroded and used. To solve the problem of short life, a method for producing adipic acid, hexamethylenediamine sulfate and polyhexamethylene mono(bi)guanidine sulfate by depolymerization of nylon 66 is provided. Based on the original technology, a new A kind of depolymerization nylon-66 with sulfuric acid, obtains the product hexamethylene diamine sulfate as raw material and directly prepares the production process method of disinfectant polyhexamethylene mono(bi)guanidine sulfate, and its technological process is simple, green and environment-friendly, and cost is low , high benefit

Method used

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  • Method for producing adipic acid, hexamethylenediamine sulfate and polyhexamethylene (di)guanidine sulfate from nylon-66 through depolymerization
  • Method for producing adipic acid, hexamethylenediamine sulfate and polyhexamethylene (di)guanidine sulfate from nylon-66 through depolymerization

Examples

Experimental program
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Effect test

Embodiment 1

[0035] (1) Acid hydrolysis section: first add 2200Kg of water to the reactor, then add 1000Kg of 98% industrial sulfuric acid, then add 1000Kg of nylon-66 waste while heating, and react for 10 hours under normal pressure and 100-110°C. The reaction conversion rate reaches more than 96%, and the acid hydrolysis solution is obtained;

[0036] (2) Adipic acid refining section: cool down the acid hydrolysis solution to 30-50° C., and separate with a coarse filter to obtain crude adipic acid crystals. Heat the water temperature in the decolorization kettle to above 90°C. At this time, gradually add crude adipic acid solids equivalent to 50% of the water weight ratio. After dissolving, add activated carbon equivalent to 3% by weight, stir and decolorize, and use a plate and frame filter Separating activated carbon and insoluble impurities, then cooling and crystallizing, filtering, and drying to obtain pure adipic acid with a purity of more than 99.7%, 500Kg, and a yield of 77%;

...

Embodiment 2

[0040] Acid hydrolysis section (1), adipic acid refining section (2) and hexamethylenediamine sulfate refining section (3) are the same as in Example 1.

[0041] (4) In the preparation section of polyhexamethylene mono(bi)guanidine sulfate, the dicyandiamide and ammonium sulfate powder with a molar ratio of 1:1 are dropped into the reactor, under nitrogen protection, stirred for 10-30 minutes, and heated to 180 ℃, stirred and reacted for 3 hours, slowly added the hexamethylenediamine sulfate powder obtained in the refining section of hexamethylenediamine sulfate, and continued the reaction for 6 hours to obtain a mixture of polyhexamethylene monoguanidine sulfate and ammonium sulfate, which was melted with nitrogen while it was hot. The reaction solution in this state is slowly pressed into a separation tank filled with absolute ethanol, stirred thoroughly and filtered, and the ethanol filtrate of polyhexamethylene monoguanidine sulfate is distilled under reduced pressure to re...

Embodiment 3

[0043] Acid hydrolysis section (1), adipic acid refining section (2), hexamethylenediamine sulfate refining section (3) and polyhexamethylene mono(bi)guanidine sulfate preparation section (4) are the same as in Example 2.

[0044] Add 300Kg of hot water (70±5°C) to the crude ammonium sulfate white powder obtained after the above filtration, stir, dissolve and filter, evaporate and concentrate under reduced pressure until crystals are precipitated, cool, filter, and vacuum dry to obtain 195Kg of refined ammonium sulfate Solid, the yield is above 83%. According to the reaction equivalence ratio, fresh ammonium sulfate is properly supplemented and recycled to the polyhexamethylene mono(bi)guanidine sulfate preparation section (4).

[0045] The general molar ratio herein refers to allowing the molar ratio to fluctuate by 10% on the basis of equivalent reaction.

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Abstract

The invention discloses a method for producing adipic acid, hexamethylenediamine sulfate and polyhexamethylene (di)guanidine sulfate from nylon-66 through depolymerization, which is characterized by comprising the following steps of: depolymerizing the waste nylon-66 by using 28 to 35 percent sulfuric acid to obtain refined adipic acid and hexamethylenediamine sulfate; polymerizing the hexamethylenediamine sulfate serving as a raw material and dicyandiamide at the temperature of between 170 and 200 DEG C for 3 to 9 hours to obtain white or pale yellow polyhexamethylene diguanidine sulfate; reacting the dicyandiamide with ammonium sulfate at the temperature of between 170 and 190 for 1 to 3 hours, and adding the hexamethylenediamine sulfate to continue the reaction for 3 to 7 hours to obtain white or pale yellow polyhexamethylene guanidine sulfate. The method solves the problems of low recovery rate of the hexamethylenediamine sulfate and poor benefit in the conventional nylon-66 recovering process, and develops the stable, low-toxin and high-efficiency disinfectant polyhexamethylene (di)guanidine sulfate; and the technological process is simple, convenient, environment-friendly and safe.

Description

technical field [0001] The invention relates to a method suitable for industrial production of depolymerized nylon-66 to produce adipic acid, hexamethylene diamine sulfate and polyhexamethylene mono(bi)guanidine sulfate, and especially introduces the disinfectant polyhexamethylene Mono(bi)guanidine sulfate method. Background technique [0002] Nylon-66, also known as polyamide 66, is the first polyamide fiber product successfully researched and industrialized by human beings. Due to its excellent performance, it has been developed rapidly and its application range is expanding day by day. At present, my country's annual production of nylon-66 reaches 80,000 tons. During its synthesis and spinning process, about 10% of defective products and leftovers such as waste silk, short silk and miscellaneous debris are produced. In addition, nylon engineering parts will be discarded everywhere after being used in different industrial sectors, which not only causes waste, but also p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C55/14C07C51/06C07C211/12C07C209/50C08G73/00A01N47/44A01P1/00
Inventor 王邃张振民魏丹毅孙利民李海龙
Owner NINGBO UNIV
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