Ion Catalyst for PET Chemical Recycling

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Solution Overview

Problem

Current PET chemical recycling technologies require separate processes for depolymerization and decolorization, and recycling of catalysts is challenging, leading to increased costs.

Innovation Solution

A preparation method for an ion catalyst material involving the addition of metal chloride to an alkylimidazole-chloride ionic liquid, grafted onto a porous carrier, which is used in a PET chemical recycling method to achieve simultaneous decolorization and depolymerization of PET waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate processes are used for depolymerization and decolorization, then each process can be optimized independently, but the overall process complexity increases and recycling cost increases

Engineering Contradiction:
Improveprocess optimizationVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines depolymerization and decolorization functions into a single catalytic system. The catalyst comprises metal chloride (FeCl3, ZnCl2, or CoCl2) combined with alkylimidazole-chloride ionic liquid, which simultaneously performs both depolymerization and decolorization of PET waste in one process step, eliminating the need for separate processing stages

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The catalytic system is designed to perform multiple functions simultaneously - the metal chloride component catalyzes depolymerization while the ionic liquid component provides decolorization capability. This multi-functional catalyst reduces process complexity by consolidating what would traditionally require separate treatment steps

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If traditional catalysts are used without recycling capability, then the process is simpler, but recycling cost significantly increases

Engineering Contradiction:
Improveprocess simplicityVSAvoidcatalyst loss
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent enables recovery and recycling of the catalyst through its unique formulation. The catalyst can be separated from the reaction mixture and reused, reducing catalyst loss and enabling economic viability. The ionic liquid component facilitates catalyst recovery while maintaining catalytic activity for subsequent batches

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The catalytic system is designed to be self-contained and reusable. The combination of metal chloride and ionic liquid creates a stable catalytic system that maintains its functionality across multiple cycles, reducing the need for continuous addition of fresh catalyst and enabling economic operation

Inventive Principle:
Principle #25Self-service

3Reliability

If a porous carrier is used to improve decolorization ability, then decolorization efficiency increases, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvedecolorization abilityVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs porous carriers (such as porous polymer beads or activated carbon) to enhance the catalyst's decolorization capability. The porous structure provides high surface area for catalytic activity and facilitates mass transfer, improving decolorization efficiency while maintaining reasonable manufacturability through established porous material synthesis methods

Inventive Principle:
Principle #31Porous materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method enables efficient decolorization and depolymerization of PET waste, facilitating recycling and reducing costs by simplifying the process and enabling catalyst recycling.

Implementation Method 1

A metal chloride is added to an alkylimidazole-chloride ionic liquid to form a bisalkylimidazole-metal tetrachloride ionic liquid

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

a bisalkylimidazole-metal tetrachloride ionic liquid that is grafted on a porous carrier

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

A PET chemical recycling ion catalyst material prepared by the above-mentioned preparation method of an ion catalyst material for PET chemical recycling is added to PET waste and ethylene glycol, followed by heating and stirring to obtain depolymerized and decolorized bis(2-hydroxyethyl)terephthalate (BHET)

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 4

followed by heating and stirring to obtain depolymerized and decolorized bis(2-hydroxyethyl)terephthalate (BHET)

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentUS20250153159A1Pet chemical recycling method
Publication Date: 2025.05.15 NANYA PLASTICS CORP

AI summary

Provided is a PET chemical recycling method. The PET chemical recycling method includes the following: adding a PET chemical recycling ion catalyst material for PET chemical recycling to PET waste and ethylene glycol; heating and stirring to obtain depolymerized and decolorized bis(2-hydroxyethyl)terephthalate (BHET); and filtering and recycling the ion catalyst material for PET chemical recycling. The PET chemical recycling ion catalyst material is a bisalkylimidazole-metal tetrachloride ionic liquid grafted on a porous carrier.