CN-122010754-A - Method for depolymerizing nylon 6 waste into aminocaproic acid monomer

Abstract

The invention discloses a method for depolymerizing nylon 6 waste into aminocaproic acid monomer, which comprises the following steps of dispersing crushed nylon 6 waste into hydrogen peroxide water solution, adding titanium silicon molecular sieve, heating and stirring to depolymerize nylon 6, and obtaining depolymerized products containing aminocaproic acid monomer, wherein the mass concentration of the hydrogen peroxide water solution is 0.8-2.4%, the mass ratio of the titanium silicon molecular sieve to the nylon 6 waste is (0.02-0.1): 1, and the heating temperature is controlled at 70-90 ℃. The method provided by the invention can depolymerize the nylon 6 waste, has the characteristics of mild reaction conditions, low reaction temperature and low pressure, has a simple and easy-to-operate preparation process, can greatly reduce the production cost, and can be effectively applied to depolymerization of the nylon 6 waste.

Inventors

• YU BAOWEI
• SUN FEILONG
• Mo Zhanghuan
• MA WEI
• GAO JIAN
• ZHOU ZHEN

Assignees

• 郑州大学

Dates

Publication Date

20260512

Application Date

20260205

Claims (9)

1. 1. A method for depolymerizing nylon 6 waste into aminocaproic acid monomers, comprising the steps of: Dispersing crushed nylon 6 waste into hydrogen peroxide water solution, adding titanium silicon molecular sieve, heating and stirring to depolymerize nylon 6, and obtaining depolymerized product containing aminocaproic acid monomer; The mass concentration of the hydrogen peroxide aqueous solution is 0.8% -2.4%, the mass ratio of the titanium silicon molecular sieve to the nylon 6 waste material is (0.02-0.1): 1, and the heating temperature is controlled at 70-90 ℃.
2. 2. The method for depolymerizing nylon 6 waste into aminocaproic acid monomer according to claim 1, wherein the mass concentration of the aqueous hydrogen peroxide solution is 1.5-2%.
3. 3. The method for depolymerizing nylon 6 waste into aminocaproic acid monomer according to claim 1 or 2, wherein the mass of the aqueous hydrogen peroxide solution is 10-20 times the mass of the nylon 6 waste.
4. 4. The method for depolymerizing nylon 6 waste into aminocaproic acid monomer according to claim 3, wherein the mass of the aqueous hydrogen peroxide solution is 12-18 times the mass of the nylon 6 waste.
5. 5. The method for depolymerizing nylon 6 waste into aminocaproic acid monomer according to claim 1 or 2, wherein the titanium silicalite molecular sieve is a TS-1 molecular sieve with a mass ratio of (0.04-0.08) to nylon 6 waste of 1.
6. 6. The method for depolymerizing nylon 6 waste into aminocaproic acid monomer according to claim 1 or 2, wherein the heating temperature is controlled at 80-90 ℃.
7. 7. The method for depolymerizing nylon 6 waste into aminocaproic acid monomer according to claim 1 or 2, wherein the depolymerization time is 1h to 5h.
8. 8. The method for depolymerizing nylon 6 waste into aminocaproic acid monomer according to claim 7, wherein the depolymerization time is 2.5-3 hours.
9. 9. The method of depolymerizing nylon 6 waste material into aminocaproic acid monomer according to claim 1 or 2, wherein the pressure of the depolymerization is normal pressure.

Description

Method for depolymerizing nylon 6 waste into aminocaproic acid monomer Technical Field The invention belongs to the technical field of nylon waste material recovery, and particularly relates to a method for depolymerizing nylon 6 waste into aminocaproic acid monomers. Background Nylon (Nylon) is a generic term for a class of synthetic polyamide fibers, which belongs to thermoplastic resins. Wherein nylon 6, also called PA6, polyamide 6, chinlon 6, etc., has the structural formula: ; Nylon plays an important role in a number of industries such as textile, automotive, electronics, packaging, and the like. Nylon belongs to a synthetic polymer material, is difficult to degrade naturally, causes long-term accumulation in the environment, forms white pollution and forms threat to the ecological system and human health. Meanwhile, nylon production relies on non-renewable resources such as petroleum, and as resources are exhausted and environmental awareness is enhanced, searching for a sustainable nylon treatment mode becomes particularly important. The nylon waste is decomposed into monomers or oligomers by a chemical method, so that the nylon waste is recycled. The nylon recycling modes are three types, namely physical recycling, chemical recycling and energy recycling. Wherein, physical recovery and energy recovery have the problems of low efficiency, pollution, high energy consumption and the like. Therefore, chemical recovery is the most suitable recovery means. Common methods for nylon chemical recovery are hydrolysis, ammonolysis, alcoholysis, and the like. However, these methods have problems such as an excessively high reaction temperature and an excessively high pressure. Disclosure of Invention The invention aims to solve the technical problems and overcome the defects and shortcomings in the background art, and provides a method for depolymerizing nylon 6 waste into aminocaproic acid monomers. In order to solve the technical problems, the technical scheme provided by the invention is as follows: a method for depolymerizing nylon 6 waste into aminocaproic acid monomers comprising the steps of: Dispersing crushed nylon 6 waste into hydrogen peroxide water solution, adding titanium silicon molecular sieve, heating and stirring to depolymerize nylon 6, and obtaining depolymerized product containing aminocaproic acid monomer; The mass concentration of the hydrogen peroxide aqueous solution is 0.8% -2.4%, the mass ratio of the titanium silicon molecular sieve to the nylon 6 waste material is (0.02-0.1): 1, and the heating temperature is controlled at 70-90 ℃. Further, the mass concentration of the hydrogen peroxide aqueous solution is 1.5-2%. Further, the mass of the hydrogen peroxide aqueous solution is 10-20 times of that of the nylon 6 waste. Further, the mass of the hydrogen peroxide aqueous solution is 12-18 times of that of the nylon 6 waste. Further, the titanium silicalite molecular sieve is a TS-1 molecular sieve, and the mass ratio of the titanium silicalite molecular sieve to nylon 6 waste material is (0.04-0.08): 1. Further, the heating temperature is controlled to be 80-90 ℃. Further, the depolymerization time is 1-5 h. Further, the depolymerization time is 2.5-3 hours. Further, the depolymerization pressure is normal pressure. Compared with the prior art, the invention has the beneficial effects that: The method provided by the invention can depolymerize the nylon 6 waste, has the characteristics of mild reaction conditions, low reaction temperature and low pressure, has a simple and easy-to-operate preparation process, can greatly reduce the production cost, and can be effectively applied to depolymerization of the nylon 6 waste. Drawings In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. FIG. 1 is a gas chromatogram of the reaction products 2h (example 1), 3h (example 2), 4h (example 3) with aminocaproic acid standard; FIG. 2 is a graph of the post-reaction product of example 1; FIG. 3 is a comparison of the gel chromatograms of the feedstock and hydrogen peroxide treated product of example 1; FIG. 4 is an infrared spectrum of the product of the reaction of example 2 with a standard sample of caprolactam, 6-aminocaproic acid. Detailed Description The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments are shown, for the purpose of illustrating the invention, but the scope of the invention is not limited to the specific embodiments shown. Unless defined otherwise, all technical and scientific terms used