PET Depolymerization With Choline Argininate at Ambient Conditions
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Solution Overview
Problem
Existing PET depolymerization processes using choline-based ionic liquids are not industrially attractive due to high pressure and temperature requirements, making them unsuitable for large-scale applications.
Innovation Solution
A PET depolymerization process using choline argininate ionic liquid ([Cho][Arg]) under ambient temperature and pressure conditions, facilitated by controlled synthesis and specific reaction parameters, achieves effective depolymerization to monomer bis(hydroxyethyl) terephthalate (BHET).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional choline-based ionic liquids are used for PET depolymerization, then depolymerization can be achieved, but high pressure and temperature conditions are required making the process unattractive for industrial scale
Solution Approach 1:
The patent changes the chemical parameters of the ionic liquid by selecting specific anions (acetate, propionate, butyrate, mesylate, bisulfate) paired with choline cation, and optimizes the molar ratio of ionic liquid to PET (1:10 to 1:1). These parameter changes enable the depolymerization reaction to proceed efficiently at ambient temperature and pressure, resolving the contradiction between industrial attractiveness and high temperature requirements.
2Productivity
If conventional choline-based ionic liquids are used for PET depolymerization, then depolymerization can be achieved, but high pressure and temperature conditions are required making the process unattractive for industrial scale
Solution Approach 1:
The patent changes the chemical parameters of the ionic liquid by selecting specific anions (acetate, propionate, butyrate, mesylate, bisulfate) paired with choline cation, and optimizes the molar ratio of ionic liquid to PET (1:10 to 1:1). These parameter changes enable the depolymerization reaction to proceed efficiently at ambient temperature and pressure, resolving the contradiction between industrial attractiveness and high pressure requirements.
3Ease of manufacture
If mechanical recycling is used, then lower cost is achieved, but product quality is reduced and food industry use is limited
Solution Approach 1:
The patent introduces choline-based ionic liquids as an intermediary catalyst that enables chemical recycling through glycolysis. This intermediary facilitates the conversion of waste PET back to monomers under mild conditions, producing high-quality recycled PET suitable for food industry applications, thereby resolving the contradiction between low cost mechanical recycling and high quality requirements.
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 process allows PET to be depolymerized efficiently and economically, producing the starting monomer that can be repolymerized, while maintaining other material components intact, with a yield of about 10% in laboratory conditions.
Implementation Method 1
PET depolymerization process by glycolysis in the presence of choline argininate ionic liquid
Implementation Method 2
choline argininate ionic liquid ([Cho][Arg])... facilitates effective depolymerization to monomer bis(hydroxyethyl) terephthalate (BHET)
Data Source
AI summary
PET depolymerization process wherein PET, a ionic liquid consisting of (2-hydroxyethyl)trimethylammonium argininate [Cho][Arg] and methanol are mixed together at a temperature ranging from -50 to 70°C. The weight ratio of PET to the ionic liquid is between 10 and 0.05.