Hydrolysis Recycling Process for PET Bottles

A method to recycle high-viscosity PET like water bottle containers without using solvents. The method involves melting the PET, adding an alkali slurry with ethylene glycol, and reacting the melted PET in-situ to form alkali terephthalate. This is done continuously in an extruder-like reactor. The alkali terephthalate is then dissolved in water and further reacted with acid to produce terephthalic acid. The extruder-based in-situ reaction avoids the need for solvents to decompose high-viscosity PET.

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Improved process for depolymerizing polyethylene terephthalate (PET) into its monomers terephthalic acid and ethylene glycol, using a solvent system without external heat. The process involves swelling PET with a non-polar solvent like halogenated solvents, followed by mixing with an ester-degrading agent like alcohol/hydroxide, without heat, to depolymerize PET into the monomers.

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A process to depolymerize polyethylene terephthalate (PET) into terephthalic acid and ethylene glycol without external heat. The process involves swelling PET with a non-polar solvent like chlorinated solvents, followed by mixing with an alcohol-hydroxide drug. This allows degradation of the ester groups and depolymerization into starting materials for PET production.

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A process for making high purity terephthalic acid from waste polyethylene terephthalate (PET) bottles using microwave heating and solvent extraction. The PET is depolymerized by alkaline hydrolysis with microwaves. After depolymerization, the mixture is stirred with water, extracted with an organic solvent, and impurities are removed by contact with a sorbent. The terephthalic acid is then precipitated by acidification and separated. This allows selective separation of terephthalic acid from impurities in the PET depolymerization reaction.

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Efficiently depolymerizing polyethylene terephthalate (PET) into terephthalic acid and ethylene glycol without applying external heat. The process involves mixing PET with a solvent that swells the polymer, like a halogenated solvent, and an ester-breaking agent like a linear C1-C4 alcohol and a hydroxide. The mixture is agitated for 1 hour to depolymerize PET into starting materials for new PET production.

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Method to recycle mixed waste containing polyester into terephthalic acid, a key precursor for making new polyester. The process involves breaking the waste, depolymerizing the polyester to form disodium terephthalate, decolorizing and separating the disodium terephthalate, then crystallizing the terephthalic acid. The separated waste streams can be further processed into fuel or purified terephthalic acid.

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A low-energy, high-yield method to depolymerize polyesters like PET into starting materials for new polymer production without applying external heat. The method involves mixing the polymer with a solvent that swells it, an ester-breaking agent, and a linear alcohol. The solvent swelling allows internal degradation of the polymer ester bonds. The ester-breaking agent like an alcohol and base catalyzes ester hydrolysis. The process is run at ambient temperature for 1 hour without heating. The depolymerized monomers are recovered.

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A method to produce terephthalic acid in an industrially advantageous manner while suppressing an increase in concentration of a by-produced carboxylic acid mixture in the reaction system and the mother liquor. The method involves selectively recovering catalyst components (heavy metals and bromide ions) from the mother liquor using a pyridine-ring-containing chelate resin. This is done in steps: adsorbing the catalyst components and carboxylic acids from the mother liquor onto the resin, selectively eluting the carboxylic acids with dilute acetic acid, then eluting the catalyst components with water or dilute acetic acid. The eluted catalyst components are returned to the reaction, and the recovered acetic acid is reused in the reaction. This allows separating the catalyst components from the carbox

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A method for chemically regenerating polyethylene terephthalate (PET) waste back into new PET resin, without mechanical grinding. The process involves hydrolyzing the PET to separate the terephthalic acid and ethylene glycol components. A catalyst is used to facilitate the hydrolysis reaction. The catalyst is selected to selectively remove impurities like methyl-toluate and oligomeric byproducts. This allows purification of the terephthalic acid and glycol. The purified components can then be regenerated into new PET resin. The process is continuous and can be performed in a specialized regenerating device.

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Recovering terephthalic acid from recycled PET plastic bottles in an efficient, short, and industrial process. The method involves thermally decomposing crushed PET in a solvent like ethylene glycol (EG) and an alkali under atmospheric or reduced pressure to form terephthalic acid and EG. The solvent is then evaporated to isolate the solid terephthalic acid. This avoids complex solvent separation steps compared to prior methods. The apparatus includes a reaction chamber, decompression chamber, and evaporation container.

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