Systems, methods, and compositions for upcycling polyesters

Abstract

In some aspects, the present disclosure provides a process of producing a polyester. In some embodiments, the process comprises a depolymerization process and a polymerization process. In some embodiments, the depolymerization process comprises 1) adding a first alcohol to a first composition comprising a first polyester, and 2) subjecting the first polyester and the first alcohol to conditions such that the first polyester depolymerizes to form a second composition comprising an ester derivative. In some embodiments, the polymerization process comprises subjecting the ester derivative to conditions such that the ester derivative polymerizes to form a third composition comprising a second polyester and a second alcohol.

Description

SYSTEMS, METHODS, AND COMPOSITIONS FOR UPCYCLING POLYESTERSCROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 584,834, filed September 22, 2023, which is entirely incorporated herein by reference.BACKGROUND

[0002] Polyesters are commonly used as synthetic fiber, film, container plastics, and specialty plastics applications. Polyethylene terephthalate (PET), for example, is a common commodity polyester polymer used for making plastic bottles and containers. The largest polyester sector is the fibers market where polyester fibers are used to make clothes, textiles (e.g., sheets, curtains, carpets, rugs, etc.), and industrial products (e.g., tire cord, seat belts, hoses, , ropes, etc). PET film is utilized in electrical applications such as dielectric metal foil capacitors and for food packaging. Polyesters are generally produced from fossil fuels and many polyesters are discarded after being used only once. Thus, a large quantity of polyesters end up in landfills and oceans.SUMMARY

[0003] In some aspects, the present disclosure provides a system for producing polyester, the system comprising: a depolymerization module configured to receive a first alcohol and a first polyester in a first composition to form a second composition comprising a glycol and a terephthalate; a separation module configured to separate the terephthalate from the glycol; and a polymerization module configured to receive the terephthalate and the glycol to form a third composition comprising a second polyester and a second alcohol; wherein the first alcohol used in the depolymerization module comprises at least a portion of the second alcohol formed in the polymerization module.

[0004] In some embodiments, the separation module comprises a filtration module. In some embodiments, the filtration module is a belt filter, a screw press, or a filter press, or a combination thereof. In some embodiments, the separation module further comprises one or more screeners configured to remove a solid waste. In some embodiments, the screener is upstream of the filtration module. In some embodiments, the screener is a vibrating screen filter, a trommel screen filter, a rotating screen filter, a sieve filter, a decanting screen filter, or a combination thereof . In some embodiments, the depolymerization module is fluidically coupled to the separation module. In some embodiments, the polymerization module is fluidically coupled to the separation module.

[0005] In some embodiments, the system further comprises a glycol recovery module configured to receive a mixture comprising glycol byproduct from the polymerization module. In some embodiments, the glycol recovery module comprises an evaporator column and at least one separation column downstream of the evaporator column. In some embodiments, the glycol recovery module is configured to produce recycled glycol. In some embodiments, the polymerization module is further configured to receive the recycled glycol to form the third composition.

[0006] In some embodiments, the glycol recovery module is configured to receive a mixture comprising glycol byproduct from the polymerization module. In some embodiments, the glycol recovery module comprises an evaporator column and at least one separation column downstream of the evaporator column. In some embodiments, the polymerization module is further configured to receive the recycled glycol to form the third composition.

[0007] In some embodiments, the first alcohol and the second alcohol is methanol. In some embodiments, the glycol is monoethylene glycol (MEG).

[0008] In some aspects, provided herein is a method for upcycling a polyester comprising a first purity. In some embodiments, the method comprises upcycling the polyester to produce a second polyester, wherein the second polyester comprises a second purity equal to or greater than the first purity, and wherein the second polyester comprises at least 70 wt% of the polyester. In some embodiments, the upcycling comprises depolymerizing the polyester and polymerizing the second polyester. In some embodiments, the second polyester comprises from about 75 wt% to about 99.5 wt% of the polyester.

[0009] In some aspects, provided herein is a waste polyester feedstock conditioning system, the system comprising: a feedstock collection vessel configured to receive a waste product comprising polyethylene terephthalate (PET); a magnetic separator unit configured to reduce a metal content from the waste product to no greater than 2 w / w%; and a drying unit configured to dry the waste product to reduce a water content to no greater than 500 ppm. In some embodiments, the waste polyester feedstock conditioning system is upstream of a depolymerization system and is configured to produce a waste polyester feedstock. In some embodiments, the waste polyester feedstock comprises from about 0.5 w / w% to about 25 w / w% non-PET contaminants. In some embodiments, the conditioning system does not comprise a module configured to melt the waste product or the waste polyester feedstock.

[0010] In some aspects, provided herein is a PET depolymerization system, the system comprising: one or more depolymerization reactor vessels configured to: receive a reaction mixture comprising a waste polyester feedstock, an alcoholic solvent, and a depolymerization catalyst; and carry out analcoholysis reaction on the reaction mixture to form a depolymerization slurry; one or more filtration units configured to separate the depolymerization slurry into a solid fraction and a liquid fraction; and one or more separation modules configured to recover and recycle the alcoholic solvent, wherein the waste polyester feedstock comprises polyethylene terephthalate (PET) and from about 0.5 w / w% to about 25 w / w% non-PET contaminants, and wherein the alcoholysis reaction is carried out at a temperature not exceeding 100 °C.

[0011] In some aspects, provided herein is a PET depolymerization system comprising: one or more depolymerization reactor vessels configured to receive a reaction mixture comprising a waste polyester feedstock, an alcoholic solvent, and a depolymerization catalyst; and carry out an alcoholysis reaction on the reaction mixture to form a depolymerization slurry; one or more filtration units configured to separate the depolymerization slurry into a solid fraction and a liquid fraction; and one or more separation modules configured to recover and recycle the alcoholic solvent, wherein the waste polyester feedstock comprises polyethylene terephthalate (PET) and from about 0.5 w / w% to about 25 w / w% non-PET contaminants, and wherein the alcoholysis reaction is carried out at a pressure not exceeding 120 psi.

[0012] In some aspects, provided herein is a glycol purification system comprising: a neutralization unit configured to react a liquid fraction comprising glycol with an acid to form a neutralized mixture; a first distillation unit configured to distill and recover methanol distillate from the neutralized mixture and a first bottom; and one or more subsequent distillation units configured to distill and recover glycol from the first bottom, wherein the glycol purification system is downstream of a depolymerization system. In some embodiments, the glycol purification system is fluidically coupled with a polymerization system. In some embodiments, the liquid fraction comprising glycol is at least partially from the polymerization system. In some embodiments, the glycol is monoethylene glycol.

[0013] In some aspects, provided herein is a system comprising: an ester exchanger unit configured to carry out a transesterification reaction of a recycled terephthalate content and a recycled glycol content to form one or more byproducts, wherein the one or more byproducts comprise a glycol byproduct and a PET oligomer byproduct; one or more melt phase polycondensation units configured to produce one or more vapor streams, wherein the one or more vapor streams comprises a glycol vapor content and a PET oligomer vapor content; and a glycol recovery unit configured to receive a glycol mixture collected and condensed from the one or more vapor streams.

[0014] In some aspects, provided herein is a glycol recovery system comprising: one or more glycol collection tanks configured to collect a mixture formed from one or more vapor streams ofan upstream PET polymerization system, wherein the one or more vapor streams comprises one or more byproducts, wherein the one or more byproducts comprise a glycol byproduct and a PET oligomer byproduct; one or more evaporation units configured to partially vaporize the mixture to form a gaseous phase and a liquid phase; one or more sludge collection units configured to store the liquid phase of the evaporation unit; and one or more separation units configured to form a condensate from the gaseous phase of the evaporation unit and separate the condensate into a collection fraction and a waste fraction, wherein the collection fraction comprises glycol having a purity of at least 99 w / w%. In some embodiments, the glycol recovery system further comprises one or more glycol collection tanks configured to receive the collection fraction recovered from the separation unit. In some embodiments, the glycol in the collection fraction is monoethylene glycol.

[0015] In some aspects, the present disclosure provides a glycol waste recovery system comprising: one or more glycol collection tanks configured to collect a mixture formed from one or more vapor streams of an upstream PET polymerization system, wherein the one or more vapor streams comprises one or more byproducts, wherein the one or more byproducts comprise a glycol byproduct and a PET oligomer byproduct; one or more evaporation units configured to partially vaporize the mixture to form a gaseous phase and a liquid phase; one or more sludge collection units configured to store the liquid phase of the evaporation unit; and one or more separation units configured to form a condensate from the gaseous phase of the evaporation unit and separate the condensate into a collection fraction and a waste fraction, wherein the collection fraction comprises glycol having a purity of at least 99 w / w%. In some embodiments, the glycol waste recovery system further comprises one or more glycol collection tanks configured to receive the collection fraction recovered from the separation unit. In some embodiments, the glycol waste recovery system further comprises a glycol purification subsystem configured to purify the waste fraction and recover monoethylene glycol.

[0016] Provided herein, in some aspects, is a system comprising: an ester exchanger unit configured to carry out a transesterification reaction of a recycled terephthalate content and a recycled glycol content to form one or more byproducts comprising a glycol byproduct and a PET oligomer byproduct; and one or more melt phase polycondensation units configured to produce one or more vapor streams comprising a PET oligomer vapor content; and a PET oligomer recovery unit configured to condense and collect the PET oligomer vapor content to form a PET oligomer condensate; and a depolymerization subsystem configured to receive the PET oligomer condensate and depolymerize the PET oligomers to recover a terephthalate and / or a glycol, wherein the depolymerization subsystem is at most 1 kilometer downstream of the ester exchanger unit and the one or more melt phase polycondensation units.

[0017] Provided herein, in some aspects, is an integrated process for producing recycled polyethylene terephthalate (r-PET) comprising: subjecting a waste polyester feedstock comprising PET to a depolymerization process, wherein the waste polyester feedstock comprises from about 75 w / w% PET to about 99 w / w% PET, wherein the depolymerization comprises: admixing the waste polyester feedstock with at least one portion of a solvent, thereby forming a first reaction mixture; admixing the first reaction mixture with a depolymerization catalyst, thereby forming a second reaction mixture comprising a solid fraction and a liquid fraction; performing a first purification, wherein the first purification comprises melting the solid fraction to form a DMT melt, and distilling the DMT melt to yield r-DMT; performing a second purification, wherein the second purification comprises: neutralizing the liquid fraction with an acid to form a neutralized mixture, subjecting the neutralized mixture to at least two distillations to yield a methanol distillate and a MEG distillate, wherein the methanol distillate comprises a recycled methanol (r-methanol) content and the MEG distillate comprises a recycled MEG (r-MEG) content; subjecting the r-DMT content and the r-MEG content to a polymerization process, thereby forming r-PET.

[0018] In some aspects, the present disclosure provides an integrated process for producing recycled polyethylene terephthalate (r-PET) comprising: subjecting a waste polyester feedstock comprising PET to a depolymerization process in a first location, wherein the depolymerization comprises: admixing the waste polyester feedstock with at least one portion of a solvent, thereby forming a first reaction mixture; admixing the first reaction mixture with a depolymerization catalyst, thereby forming a second reaction mixture comprising a solid fraction and a liquid fraction; performing a first purification, wherein the first purification comprises melting the solid fraction to form a DMT melt, and distilling the DMT melt form a DMT distillate, wherein the DMT distillate comprises a recycled DMT (r-DMT) content; performing a second purification, wherein the second purification comprises: neutralizing the liquid fraction with an acid to form a neutralized mixture; subjecting the neutralized mixture to at least a first distillation to yield a methanol distillate and a first bottom; subjecting the first bottom to one or more distillations to yield a subsequent distillate, wherein the subsequent distillate comprises a recycled MEG (r-MEG) content; and subjecting the r-DMT content and the r-MEG content to a polymerization process in a second location, thereby forming the r-PET, wherein the first location has a distance of at most 1 kilometer from the second location.

[0019] In certain aspects, provided herein is a process for recovering MEG from a polyethylene terephthalate polymerization process, comprising: collecting a mixture from one or more vapor streams of the polymerization process, wherein the polymerization process comprises an ester exchanger phase and a melt phase polycondensation phase; evaporating the mixture to form a liquidphase and a gaseous phase; and subjecting the liquid phase to at least one separation process to form a waste fraction and a collection fraction, thereby recovering MEG from the collection fraction.

[0020] In some aspects, provided herein is a process for recovering dimethyl terephthalate (DMT) and ethylene glycol (EG) from polyethylene terephthalate (PET) oligomers comprising: collecting a mixture comprising PET oligomers from one or more vapor streams of a polymerization process, wherein the polymerization process comprises an ester exchanger phase and a melt phase polycondensation phase; and subjecting at least a portion of the mixture to a depolymerization process, thereby recovering DMT and MEG.

[0021] In some aspects, the present disclosure provides a process for recovering ethylene glycol comprising: collecting a mixture comprising ethylene glycol from one or more vapor streams of a polymerization process, wherein the polymerization process comprises an ester exchanger phase and a melt phase polycondensation phase; evaporating the mixture to form a liquid phase and a gaseous phase; subjecting the liquid phase to at least one separation process to form a waste fraction and a collection fraction, wherein the collection fraction comprises MEG; and subjecting the waste fraction to a purification process comprising: neutralizing the waste fraction with at least one portion of an acid to form a neutralized mixture; adding a portion of methanol to the neutralized mixture, and subjecting the neutralized mixture to a first distillation to form a first distillate and a first bottom, thereby recovering methanol from the first distillate; subjecting the first bottom to one or more subsequent distillations, thereby recovering ethylene glycol from a final distillate.

[0022] In some aspects, the present disclosure provides a process of producing a polyester, the process comprising a depolymerization process and a polymerization process; wherein the depolymerization process comprises 1) adding a first alcohol to a first composition comprising a first polyester, and 2) subjecting the first polyester and the first alcohol to conditions such that the first polyester depolymerizes to form a second composition comprising an ester derivative; and wherein the polymerization process comprises subjecting the ester derivative to conditions such that the ester derivative polymerizes to form a third composition comprising a second polyester and a second alcohol.

[0023] In some embodiments, the first polyester depolymerizes to form the ester derivative and a first glycol. In some embodiments, the polymerization process comprises subjecting the ester derivative and a second glycol to conditions such that they polymerize. In some embodiments, the first glycol and the second glycol comprise the same chemical structure. In some embodiments, the first glycol and the second glycol comprise different chemical structures. In some embodiments, thefirst polyester and the second polyester comprise the same repeat unit. In some embodiments, the first polyester and the second polyester comprise different repeat units. In some embodiments, the first alcohol and the second alcohol comprise the same chemical structure. In some embodiments, the first alcohol and the second alcohol comprise different chemical structures. In some embodiments, the ester derivative is a terephthalate. In some embodiments, the first alcohol comprises at least a portion of the second alcohol recycled from the third composition. In some embodiments, the second glycol comprises at least a portion of the first glycol recycled from the second composition. In some embodiments, the ester derivative in the polymerization process is purified from the depolymerization process or the polymerization process. In some embodiments, the first alcohol is purified from the depolymerization process or the polymerization process. In some embodiments, the second alcohol is purified from the depolymerization process or the polymerization process. In some embodiments, the first glycol is purified from the depolymerization process or the polymerization process. In some embodiments, the second glycol is purified from the depolymerization process or the polymerization process.

[0024] In some embodiments, the depolymerization process and the polymerization process are performed within about 10 meters, about 20 meters, about 30 meters, about 40 meters, about 50 meters, about 60 meters, about 70 meters, about 80 meters, about 90 meters, about 100 meters, about 200 meters, about 300 meters, about 400 meters, about 500 meters, about 1,000 meters, about 2,000 meters, about 3,000 meters, about 4,000 meters, about 5,000 meters, about 6,000 meters, about 7,000 meters, about 8,000 meters, about 9,000 meters, or about 10,000 meters. In some embodiments, the depolymerization process is adjacent to an alcohol purification process. In some embodiments, the depolymerization process is adjacent to a terephthalate purification process. In some embodiments, the depolymerization process and the polymerization process are fluidically coupled.

[0025] In some embodiments, the first composition comprises recycled polyester material or nonrecycled polyester material. In some embodiments, the first composition comprises post-consumer PET. In some embodiments, the first composition comprises polyester fiber. In some embodiments, the first composition comprises one or more byproducts collected from a polymerization process. In some embodiments, the one or more byproducts comprises recycled PET (r-PET) oligomers. In some embodiments, the first composition comprises an impurity. In some embodiments, the first composition comprises at least about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 85 wt%, about 90 wt%, about 95 wt%, about 96 wt%, about 97 wt%, about 98 wt%, about 99 wt%, about 99.1 wt%, about 99.2 wt%, about 99.3 wt%, about 99.4 wt%, about 99.5 wt%, about 99.6 wt%, about 99.7 wt%, about 99.8 wt%, or about 99.9wt% of the first polyester. In some embodiments, the first composition comprises at most about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 85 wt%, about 90 wt%, about 95 wt%, about 96 wt%, about 97 wt%, about 98 wt%, about 99 wt%, about 99.1 wt%, about 99.2 wt%, about 99.3 wt%, about 99.4 wt%, about 99.5 wt%, about 99.6 wt%, about 99.7 wt%, about 99.8 wt%, or about 99.9 wt% of the first polyester. In some embodiments, the first composition comprises polyester flakes, polyester fines, polyester purge fines, polyester fibers, densified polyester fibers, or any combination thereof. In some embodiments, the first composition comprises polyesters comprising mixed colors. In some embodiments, the first composition comprises at least one of: polyethylene, polypropylene, polyvinylidene chloride, ethylene-vinyl acetate, ethylene-vinyl alcohol copolymer, an elastomer, paper-based material, ethylene propylene diene monomer (EPDM) rubber, nylon, chlorosulfonated polyethylene, polyamide, aramid, polyvinylchloride-polyvinyl acrylic acid copolymer, polystyrene, styrene butyl methacrylate copolymer, silicone rubber, wood, polyacrylate, polydimethylsiloxane, rubber, neprone, chlorobutyl polycorp, polytetrafluoroethylene, fiberglass, styrene butadiene rubber, or any combination thereof. In some embodiments, the paper-based material comprises packaging material. In some embodiments, the packaging material comprises cardboard.

[0026] In some embodiments, the first alcohol is continuously added to the depolymerization process. In some embodiments, the first glycol is continuously added to the polymerization process. In some embodiments, the depolymerization process further comprises adding alcohol not from the depolymerization process or the polymerization process to the first composition. In some embodiments, the depolymerization process further comprises adding the alcohol not from the depolymerization process or the polymerization process to the first composition before or after the recycled alcohol is added to the first composition. In some embodiments, the polymerization process further comprises adding glycol not from the depolymerization process or the polymerization process to the terephthalate. In some embodiments, the depolymerization process further comprises adding the alcohol not from the depolymerization process or the polymerization process to the terephthalate before or after the recycled glycol is added to the terephthalate.

[0027] In some embodiments, the first polyester, the second polyester, or both comprises: polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene sebacate), poly(ethylene adipate), poly(ethylene isophthalate), poly(ethylene phthalate), poly(butylene sebacate), poly(butylene succinate), poly(hexylene sebacate), polyhydroxybutyrate, polyethylene naphthalate, polyglycolide, polyglycolic acid, polylactic acid, polycaprolactone, poly(Bisphenol A isophthalate), poly (Bisphenol A terephthalate), poly(ethylene glycol-co-l,4-cyclohexanedimethanol terephthalate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polyester of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid, Vectran®, cutin, or any combinations thereof. In some embodiments, the first alcohol, the second alcohol, or both comprises: methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-l,4-diyldimethanol, phenol, benzyl alcohol methanol, or any combination thereof. In some embodiments, the first glycol, the second glycol, or both comprises: ethylene glycol, 1,2-propanediol, 1,3 -propanediol, 1,4-butanediol, 1,3 -butanediol, 2,3 -butanediol, 1,2- pentanediol, 1,3 -pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,3 -pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3 -hexanediol, 1,4-hexanediol, 1,5 -hexanediol, 1,6-hexanediol, 2,3 -hexanediol, 2,4-hexanediol, 2,5-hexanediol, 3,4-hexanediol, Bisphenol A, or any combination thereof.

[0028] In some embodiments, the depolymerization process uses a first catalyst. In some embodiments, the first catalyst comprises an alkoxide. In some embodiments, the alkoxide comprises: methoxide, ethoxide, n-propoxide, n-butoxide, t-butoxide, sec-butoxide, iso-butoxide, iso-propoxide, or any combination thereof. In some embodiments, the alkoxide comprises a metal alkoxide. In some embodiments, the metal alkoxide comprises a cation selected from the group consisting of: lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, ammonium, and any combination thereof. In some embodiments, the first catalyst comprises a glycoxide. In some embodiments, the glycoxide comprises a metal glycoxide. In some embodiments, the metal glycoxide comprises a cation selected from the group consisting of: lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, ammonium, and any combination thereof. In some embodiments, the polymerization process uses a second catalyst. In some embodiments, the second catalyst comprises an antimony compound or a titanium compound.

[0029] In some aspects, the present disclosure provides a separation process, comprising: providing a mixture comprising (i) a mono-alcohol, (ii) a diol, and (iii) an alkoxide; adding an acid to the mixture; and distilling the mixture to produce (i) a distillate comprising an increased ratio of the mono-alcohol to the diol compared to the mixture and (ii) a bottom comprising an increased ratio of the diol to the mono-alcohol compared to the mixture.

[0030] In some embodiments, the acid comprises: sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, phosphorous acid, carbonic acid, acetic acid, perchloric acid, chloric acid, chlorous acid, hypochi orous acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, or any combinations thereof.

[0031] In some embodiments, the process further comprises recycling the distillate for use in a polyester depolymerization process. In some embodiments, the process further comprises recycling the bottom for use in a polyester polymerization process.

[0032] In some embodiments, the distilling comprises: distilling the mixture using a first distillation column to produce the distillate and a first intermediate composition; distilling the first intermediate bottoms using a second distillation column to produce a second intermediate composition and a waste bottom; and distilling the second intermediate composition using a third distillation column to produce a waste distillate and the bottoms. In some embodiments, the distillation columns are thermally integrated.

[0033] In some aspects, the present disclosure provides a separation process, comprising: heating a mixture comprising (i) a terephthalate in a solid phase and (ii) an alcohol to melt the terephthalate; flash evaporating the mixture to evaporate the alcohol from the mixture; and distilling the mixture to produce a distillate, wherein the distillate comprises a higher fraction of the terephthalate than the mixture. In some embodiments, the process further comprises using the terephthalate flakes in a polymerization process to produce a polyester.

[0034] In some aspects, the present disclosure provides a method of producing a polyester, the method comprising a depolymerization process and a polymerization process; wherein the depolymerization process comprises 1) adding a first alcohol to a first composition comprising a first polyester, and 2) subjecting the first polyester and the first alcohol to conditions such that the first polyester depolymerizes to form a second composition comprising a terephthalate and a glycol; wherein the polymerization process comprises subjecting the terephthalate and the glycol in the second composition to conditions such that they polymerize to form a third composition comprising a second polyester and a second alcohol; wherein the first alcohol comprises at least a portion of the second alcohol recycled from the third composition.

[0035] In some embodiments, the first alcohol comprises at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% recycled second alcohol. In some embodiments, the first alcohol comprises at least about 90% recycled second alcohol. In some embodiments, the first alcohol comprises at least about 95% recycled second alcohol.

[0036] In some embodiments, the depolymerization process and the polymerization process are fluidically coupled to each other. In some embodiments, the polymerization process is performed within about 1,000 meters from the depolymerization process. In some embodiments, the terephthalate in the second composition is used in the polymerization process within about 1 hour after the terephthalate is formed in the depolymerization process. In some embodiments, the third composition comprises residual glycol not reacted in the polymerization process, and the method further comprises separating residual glycol and adding it to the polymerization process. In some embodiments, the second composition comprises residual first alcohol not reacted in thedepolymerization process, and the method further comprises separating the residual first alcohol and adding it to the depolymerization process.

[0037] In some embodiments, the first alcohol is at least one of methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-l,4-diyldimethanol, phenol, benzyl alcohol methanol, or any combination thereof. In some embodiments, the terephthalate is dimethyl terephthalate (DMT). In some embodiments, the glycol is ethylene glycol. In some embodiments, the second polyester is the same type of polyester as the first polyester. In some embodiments, the second polyester is a different type of polyester from the first polyester. In some embodiments, at least the first or the second polyester is polyethylene terephthalate (PET). In some embodiments, the first polyester comprises post-consumer PET.

[0038] In some embodiments, subsequent to the depolymerization process, the process further comprises a separation process, wherein at least one of the terephthalate and the glycol are separated from the second composition. In some embodiments, the separation process comprises removing a solid from the second composition. In some embodiments, the separation process comprises a screener configured to remove the solid from the second composition. In some embodiments, the screener comprises a pore size of less than about 1 mm. In some embodiments, the solid comprises a residual first polyester not reacted in the depolymerization process.

[0039] In some embodiments, the separation process further comprises using a vacuum belt filter to separate the terephthalate from the glycol in the second composition.

[0040] In some embodiments, the second composition comprises a residual first alcohol not reacted in the depolymerization process, and the separation process further comprises separating the residual first alcohol from the terephthalate.

[0041] In some embodiments, the separation process is performed at a pressure of about 1 atm.

[0042] In some embodiments, the separated terephthalate is in a crystalline state. In some embodiments, the separated glycol is in a liquid state.

[0043] In some embodiments, the process further comprises purifying the terephthalate subsequent to the depolymerization process and before the polymerization process.

[0044] In some embodiments, the second alcohol is continuously added to the depolymerization process.

[0045] In some embodiments, the glycol recycled from the depolymerization process is continuously added to the polymerization process.INCORPORATION BY REFERENCE

[0046] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and / or take precedence over any such contradictory material.BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The novel features of the disclosure are set forth with particularity in the appended claims. Abetter understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings of which:

[0048] FIGs. 1A and IB show examples of reaction schemes for polyester depolymerization, in accordance with some embodiments.

[0049] FIG. 2 shows an example reaction scheme for polyester polymerization, in accordance with some embodiments.

[0050] FIGs. 3A and 3B show examples of high-level process schematics for depolymerizing and polymerizing a polyester, in accordance with some embodiments.

[0051] FIG. 4 shows an example process schematic for upcycling a polyester, in accordance with some embodiments.

[0052] FIGs. 5A-5C show example reaction schemes for polyester depolymerization and polymerization, in accordance with some embodiments.

[0053] FIG. 6 shows an example process schematic for upcycling a polyester, in accordance with some embodiments.

[0054] FIG. 7 shows an example integrated polyester recycling system, in accordance with some embodiments.

[0055] FIGs. 8A-8F show various example subsystems of an integrated polyester recycling system, in accordance with some embodiments. FIG. 8A shows an example waste polyester feedstock conditioning subsystem, in accordance with some embodiments. FIG. 8B shows an example depolymerization subsystem, in accordance with some embodiments, shows an example terephthalate purification system, in accordance with some embodiments. FIG. 8C shows an example glycol purification subsystem, in accordance with some embodiments. FIG. 8D shows an example terephthalate purification subsystem, in accordance with some embodiments. FIG. 8Eshows an example polymerization subsystem, in accordance with some embodiments. FIG. 8F shows an example polymerization byproduct and waste recovery subsystem, in accordance with some embodiments.DETAILED DESCRIPTION

[0056] Waste polyesters (e.g., polyethylene terephthalate, “PET”), largely derived from nonrenewable resources (e.g., fossil fuels), often accumulate in landfills and oceans after a single use. Consequently, a large quantity of polyesters end up in landfills and oceans. In some cases, a feedstock of polyester (e.g., used or waste polyester) can comprise low-grade polyester molecules. A polymer molecule may undergo decomposition from irradiation, multiple iterations of recycling, etc. As such, in some cases, recycled polyesters may not be used for the same grade of polyester products that they come from (e.g., food-grade polyesters may not be recycled for use as foodgrade polyesters when they are contaminated with heavy metals). There is a need for methods and systems that can recycle or upcycle a used or waste polyester to a recycled polyester that has properties or characteristics that are substantially similar to or are improved than the virgin polyester or polyester synthesized from virgin monomers.

[0057] The present application provides systems, methods, and compositions that can be used to upcycle used or waste feedstocks (e.g., polyester fibers from carpets and clothing, colored plastic and opaque plastic, etc.) into virgin quality polyesters. In some embodiments, polyesters undergo an upcy cling process wherein the polymer is converted directly into a product with improved properties in comparison to the starting material. An upcycled product can comprise higher purity than a feedstock of polyester (e.g., used or waste polyester).

[0058] In some embodiments, upcycled polyesters disclosed herein can be used for the same or higher quality polyester products. For example, an unrecycleable polyester can be upcycled to food-grade polyester. Food-grade polyester can have regulatory guidelines on purity and stability, and often may be synthesized from “virgin” monomers, wherein virgin monomers may meet certain purity standards. This can divert the polyesters away from oceans and landfills, decrease greenhouse gas emissions, and reduce dependency on fossil fuels for creating more polyesters for various applications.

[0059] In some aspects, the present disclosure provides a method of depolymerizing a polyester to generate an ester derivative, and then polymerizing the ester derivative to form a new polyester. FIGS. 3A and 3B show a high-level process flow diagram (PFD) for depolymerizing and polymerizing polyesters, in accordance with some embodiments. FIG. 3A shows a PFD for depolymerizing and polymerizing polyesters, in accordance with some embodiments. Thedepolymerization stage can depolymerize a polyester using an alcohol to form an ester derivative. The polymerization stage can utilize the ester derivative, to polymerize a polyester. FIG. 3B shows a PFD for depolymerizing and polymerizing a terephthalate polyester, in accordance with some embodiments. The depolymerization stage can depolymerize a polyester using an alcohol to form a terephthalate and a glycol. The polymerization stage can utilize the terephthalate and the glycol to polymerize a polyester. The depolymerization products can be used in part or in full in the polymerization stage. For instance, the depolymerization process may depolymerize PET to produce dimethyl terephthalate (DMT) and an ethylene glycol (e.g., monoethylene glycol (MEG)), which can be reacted to form PET. In some cases, a different glycol can be used, e.g., 1,4- butanediol, with dimethyl terephthalate (DMT) to produce polybutylene terephthalate.

[0060] FIG. 4 shows a high-level process flow diagram (PFD) for recycling a terephthalate polyester, in accordance with some embodiments. An advantage of this process is that the system can operate with substantially reduced influx and outflux of raw material and waste products. Feedstock can be preprocessed (e.g., washing and / or drying) or conditioned to prepare the terephthalate polyester for depolymerization. The polyester can be provided to a depolymerization process with an alcohol and a depolymerization catalyst. Outputs from the depolymerization process can be directed to a glycol purification process and a terephthalate purification process. The glycol purification process can produce a glycol, and the terephthalate purification process can produce a terephthalate. The glycol and the terephthalate can subsequently be provided to a polymerization process with a catalyst, to produce a terephthalate polyester.Feedstock

[0061] A feedstock can comprise used, waste, or previously recycled polyester material or nonrecycled polyester material. The feedstock can comprise post-consumer PET. The feedstock can comprise one or more impurities. The used, waste, or previously recycled polyester can comprise at least about 50 wt%, at least about 55 wt%, at least about 60 wt%, at least about 65 wt%, at least about 70 wt%, at least about 75 wt%, at least about 80, at least about 85 wt%, at least about 90 wt%, at least about 95 wt%, at least about 96 wt%, at least about 97 wt%, at least about 98 wt%, at least about 99 wt%, at least about 99.1 wt%, at least about 99.2 wt%, at least about 99.3 wt%, at least about 99.4 wt%, at least about 99.5 wt%, at least about 99.6 wt%, at least about 99.7 wt%, at least about 99.8 wt%, or at least about 99.9 wt% of the feedstock. The used, waste, or previously recycled polyester can comprise at most about 50 wt%, at most about 55 wt%, at most about 60 wt%, at most about 65 wt%, at most about 70 wt%, at most about 75 wt%, at most about 80 wt%, at most about 85 wt%, at most about 90 wt%, at most about 95 wt%, at most about 96 wt%, at most about 97 wt%, at most about 98 wt%, at most about 99 wt%, at most about 99.1 wt%, at most about99.2 wt%, at most about 99.3 wt%, at most about 99.4 wt%, at most about 99.5 wt%, at most about 99.6 wt%, at most about 99.7 wt%, at most about 99.8 wt%, or at most about 99.9 wt% of the feedstock. The feedstock can comprise polyester flakes, polyester fines, polyester purge fines, polyester fibers, densified polyester fibers, or any combination thereof. The feedstock can comprise polyesters comprising mixed colors. The feedstock can comprise one or more impurities. The one or more impurities can comprise at least 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, or 50 wt% of the feedstock. The one or more impurities can comprise at most 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, or 50 wt% of the feedstock. The one or more impurities can comprise one or more metals. The one or more metals can comprise cadmium, lead, arsenic, cobalt, nickel, antimony, molybdenum, copper, tin, chromium, aluminum, iron, manganese, titanium, zinc, mercury, or a combination thereof. The feedstock can comprise one or more non-polyester polymers. The feedstock can comprise: polyethylene, polypropylene, polycarbonate, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl acetate, ethylene-vinyl alcohol copolymer, an elastomer, paper-based material, ethylene propylene diene monomer (EPDM) rubber, nylon, chlorosulfonated polyethylene, polyamide, aramid, polyvinylchloride-polyvinyl acrylic acid copolymer, polystyrene, styrene butyl methacrylate copolymer, silicone rubber, wood, polyacrylate, polydimethylsiloxane, rubber, neprone, chlorobutyl polycorp, polytetrafluoroethylene, fiberglass, styrene butadiene rubber, or any combination thereof. The paper-based material can comprise a packaging material. The packaging material can comprise cardboard.

[0062] The feedstock can comprise polymer flakes. The mean particle size of polymer flakes can be at least about 0.1 mm, at least about 0.2 mm, at least about 0.3 mm, at least about 0.4 mm, at least about 0.5 mm, at least about 0.6 mm, at least about 0.7 mm, at least about 0.8 mm, at least about 0.9 mm, at least about 1 mm, at least about 2 mm, at least about 3 mm, at least about 4 mm, at least about 5 mm, at least about 6 mm, at least about 7 mm, at least about 8 mm, at least about 9 mm, at least about 10 mm, at least about 20 mm, at least about 30 mm, at least about 40 mm, at least about 50 mm, at least about 60 mm, at least about 70 mm, at least about 80 mm, at least about 90 mm, or at least about 100 mm. The mean particle size of polymer flakes can be at most about 0.1 mm, at most about 0.2 mm, at most about 0.3 mm, at most about 0.4 mm, at most about 0.5 mm, at most about 0.6 mm, at most about 0.7 mm, at most about 0.8 mm, at most about 0.9 mm, at most about 1 mm, at most about 2 mm, at most about 3 mm, at most about 4 mm, at most about 5 mm, at most about 6 mm, at most about 7 mm, at most about 8 mm, at most about 9 mm, at most about 10mm, at most about 20 mm, at most about 30 mm, at most about 40 mm, at most about 50 mm, at most about 60 mm, at most about 70 mm, at most about 80 mm, at most about 90 mm, or at most about 100 mm. The mean particle size of polymer flakes can be from about 1 mm to about 20 mm. The mean particle size of polymer flakes can be from about 1 mm to about 15 mm. The mean particle size of polymer flakes can be from about 1 mm to about 10 mm. The mean particle size of polymer flakes can be from about 1 mm to about 5 mm.Feedstock Preprocessing

[0063] The feedstock can be preprocessed to at least partially segregate polyester from other substances (e.g., impurities). Preprocessing can comprise density separation using water, aqueous salt solutions, or another fluid comprising a density between that of the polyester and a contaminant. Preprocessing can comprise washing which can remove contaminating substances (e.g., organics, oils, etc.) adsorbed or absorbed to the polyester. Preprocessing can comprise drying. Preprocessing can comprise electrostatic separation, which can involve triboelectrically charging the feedstock and separating its constituents based on charge and / or polarity. Preprocessing can comprise size-based separation, e.g., using sieves.Feedstock Conditioning

[0064] The feedstock can be conditioned to prepare the feedstock for depolymerization. Conditioning can comprise removal of a metal content. For example, a metal content can comprise one or more metals selected from the group consisting of cadmium, lead, arsenic, cobalt, nickel, antimony, molybdenum, copper, tin, chromium, aluminum, calcium, iron, manganese, magnesium, titanium, potassium, sodium, zinc, and mercury. In some instances, the removal of the metal content may be performed to achieve a metal content of the feedstock not exceeding 5% (w / w), not exceeding 4% (w / w), not exceeding 3% (w / w), not exceeding 2% (w / w), or not exceeding 1% (w / w). In some instances, a magnetic separator may be used to remove the metal content.Conditioning can comprise drying the feedstock. In some instances, the feedstock may be dried at a temperature from about 100 degrees Celsius to about 150 degrees Celsius. In some instances, the drying may be performed to achieve a water content of the feedstock not exceeding 5% (w / w), not exceeding 4% (w / w), not exceeding 3% (w / w), not exceeding 2% (w / w), or not exceeding 1% (w / w). In some instances, the feedstock may comprise polyester fiber. In some instances, conditioning the feedstock may comprise agglomeration.Polyester Depolymerization

[0065] In one aspect, the present disclosure provides methods and systems for depolymerizing a polyester. In some embodiments, the depolymerization can comprise reacting the polyester with asolvent and a depolymerization catalyst. In some cases, the solvent can comprise an alcoholic solvent. In some cases, the catalyst can comprise an alkoxide.

[0066] In some embodiments, the process described herein comprises pre-treating the polyester with a solvent for swelling the polyester prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for from about 5 minutes to about 60 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for from about 5 minutes to about 40 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for from about 5 minutes to about 20 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for from about 5 minutes to about 10 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 5 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 10 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 15 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 20 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 25 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 30 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 35 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 40 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 45 minutes. In some embodiments, the pretreatment with the solvent for swelling the polyester is done for about 50 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 55 minutes. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 60 minutes.

[0067] In some embodiments, the process described herein comprises treating the polyester with a solvent for swelling the polyester at the same time as the addition of the alcoholic solvent and the alkoxide.

[0068] In some embodiments, the solvent for swelling the polyester is selected from the group consisting of a non polar solvent, a polar aprotic solvent, a polar protic solvent, and any combinations thereof.

[0069] In some embodiments, the solvent for swelling the polyester is selected from the group consisting of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetone, a halogenated solvent, n-hexane, nitrobenzene, methanol, ethylene glycol, benzyl alcohol, benzaldehyde, and any combinations thereof. In some embodiments, the solvent for swelling the polyester is selected from the group consisting of DMSO, a halogenated solvent, and any combinations thereof. In some embodiments, the solvent for swelling the polyester is DMSO. In some embodiments, the solvent for swelling the polyester is a halogenated solvent. In some embodiments, the solvent for swelling the polyester is a chlorinated solvent. In some embodiments, the solvent for swelling the polyester is selected from the group consisting of dichloromethane, dichloroethane, tetrachloroethane, chloroform, tetrachloromethane, trichloroethane, or any combinations thereof. In some embodiments, the solvent for swelling the polyester is dichloromethane. In some embodiments, the solvent for swelling the polyester is methanol.

[0070] In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is from about 0.1 : 1 (w:w) and about 2: 1 (w:w). In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is from about 1 : 1 (w:w) to about 2: 1 (w:w). In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is from about 0.1 : 1 (w:w) to about 2: 1 (w:w), or from about 0.2: 1 (w:w) to about 2: 1 (w:w), or from about 0.3: 1 (w:w) to about 2: 1 (w:w), or from about 0.4: 1 (w:w) to about 2: 1 (w:w), or from about 0.5: 1 (w:w) to about 2: 1 (w:w), or from about 0.6: 1 (w:w) to about 2: 1 (w:w), or from about 0.7: 1 (w:w) to about 2: 1 (w:w), or from about 0.8: 1 (w:w) to about 2: 1 (w:w), or from about 0.9: 1 (w:w) to about 2: 1 (w:w), or from about 1 : 1 (w:w) to about 2: 1 (w:w), or from about 1 :2 (w:w) to about 2: 1 (w:w), or from about 1 :3 (w:w) to about 2: 1 (w:w), or from about 1 :4 (w:w) to about 2: 1 (w:w), or from about 1 :4 (w:w) to about 2: 1 (w:w), or from about 1 :6 (w:w)to about 2: 1 (w:w), or from about 1 :7 (w:w) to about 2: 1 (w:w), or from about 1 :8 (w:w) to about 2: 1 (w:w), or from about 1 :9 (w:w) to about 2: 1 (w:w), or from about 0.5: 1 (w:w) to about 1.5: 1 (w:w), or from about 0.8: 1 (w:w) to about 1.2: 1 (w:w), or from about 0.5: 1 (w:w) to about 1 : 1 (w:w), or from about 1 : 1 (w:w) to about 1.5:1 (w:w). In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is from about 0.5: 1 (w:w) to about 1 : 1 (w:w).

[0071] In some embodiments, the process described herein comprises adding a sub-stoichiometric amount of an alkoxide. In some embodiments, the process described herein comprises adding a catalytic amount of an alkoxide.

[0072] “ Sub-stoichiometric amount”, as used herein, is used to indicate that the amount of material used is less than a stoichiometric amount. The term is used herein interchangeably with “catalytic amount.” In some embodiments, a sub-stoichiometric amount is less than or equal to about 95% ofa stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 90% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 85% of a stoichiometric amount. In some embodiments, a sub- stoichiometric amount is less than or equal to about 80% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 75% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 70% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 65% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 60% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 55% of a stoichiometric amount. In some embodiments, a sub- stoichiometric amount is less than or equal to about 50% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 45% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 40% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 35% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 30% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 25% of a stoichiometric amount. In some embodiments, a sub- stoichiometric amount is less than or equal to about 20% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 15% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 10% of a stoichiometric amount.

[0073] “ Stoichiometric amount”, as used herein, is used to indicate that the amount of material used is equivalent to the number of ester linkages present in the polyester.

[0074] “Oligomer” or “r-PET oligomer” as used herein, is used to indicate a polymeric species comprising in the range of from about 7 to about 50 chain lengths, or a polymeric species having a molecular weight of less than about 1,000 Daltons.

[0075] In some embodiments, the alkoxide may be generated in-situ by addition of an alkali metal, an alkaline earth metal, or a metal to the alcoholic solvent.

[0076] In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for a time sufficient for producing a desired product yield . In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 70% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until anabout 75% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 80% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 85% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 90% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 95% yield of desired ester is achieved.

[0077] In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for from about 10 minutes to about 5 hours, or from about 10 minutes to about 4 hours, or from about 10 minutes to about 3 hours, or from about 10 minutes to about 2 hours, or from about 20 minutes to about 2 hours, or from about 30 minutes to about 2 hours, or from about 40 minutes to about 2 hours, or from about 30 minutes to about 1 hour, or from about 30 minutes to about 1.5 hours. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for about 10 minutes, about 15 minutes, about 20 minutes, about 25 minutes, about 30 minutes, about 35 minutes, about 40 minutes, about 45 minutes, about 50 minutes, about 60 minutes, about 70 minutes, about 80 minutes, about 90 minutes, about 100 minutes, about 110 minutes, about 120 minutes, about 130 minutes, about 140 minutes, about 150 minutes, about 160 minutes, about 170 minutes, or about 180 minutes. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for about 1 hour, about 2 hours, about 3 hours, about 4 hours, or about 5 hours.

[0078] In some embodiments, the depolymerization process is conducted at about ambient temperature. Ambient temperature can refer to 25±5 °C. In some embodiments, the depolymerization process is conducted at a temperature of at least about 25 °C, at least about 30 °C, at least about 35 °C, at least about 40 °C, at least about 45 °C, at least about 50 °C, at least about 55 °C, at least about 60 °C, at least about 65 °C, at least about 70 °C, at least about 75 °C, at least about 80 °C, at least about 85 °C, at least about 90 °C, at least about 95 °C, at least about 100 °C, at least about 105 °C, at least about 110 °C, at least about 115 °C, at least about 120 °C, at least about 125 °C, at least about 130 °C, at least about 135 °C, at least about 140 °C, at least about 145 °C, or at least about 150 °C. In some embodiments, the depolymerization process is conducted at a temperature of at most about 25 °C, at most about 30 °C, at most about 35 °C, at most about 40 °C,at most about 45 °C, at most about 50 °C, at most about 55 °C, at most about 60 °C, at most about 65 °C, at most about 70 °C, at most about 75 °C, at most about 80 °C, at most about 85 °C, at most about 90 °C, at most about 95 °C, at most about 100 °C, at most about 105 °C, at most about 110 °C, at most about 115 °C, at most about 120 °C, at most about 125 °C, at most about 130 °C, at most about 135 °C, at most about 140 °C, at most about 145 °C, or at most about 150 °C. In some embodiments, the depolymerization is conducted at a temperature from about 25 °C to about 100 °C, or from about 25 °C to about 85 °C, or from about 25 °C to about 80 °C, or from about 25 °C to about 60 °C, or from about 40 °C to about 60 °C, or from about 40 °C to about 50 °C, or from about 30 °C to about 50 °C. In some embodiments, the depolymerization is conducted at about 26 °C, about 27 °C, about 28 °C, about 29 °C, about 30 °C, about 31 °C, about 32 °C, about 33 °C, about 34 °C, about 35 °C, about 36 °C, about 37 °C, about 38 °C, about 39 °C, about 40 °C, about 41 °C, about 42 °C, about 43 °C, about 44 °C, about 45 °C, about 46 °C, about 47 °C, about 48 °C, about 49 °C, about 50 °C, about 51 °C, about 52 °C, about 53 °C, about 54 °C, about 55 °C, about 56 °C, about 57 °C, about 58 °C, about 59 °C, about 60 °C, about 61 °C, about 62 °C, about 63 °C, about 64 °C, about 65 °C, about 66 °C, about 67 °C, about 68 °C, about 69 °C, about 70 °C, about 71 °C, about 72 °C, about 73 °C, about 74 °C, about 75 °C, about 76 °C, about 77 °C, about 78 °C, about 79 °C, about 80 °C, about 81 °C, about 82 °C, about 83 °C, about 84 °C, about 85 °C, about 86 °C, about 87 °C, about 88 °C, about 89 °C, about 90 °C, about 91 °C, about 92 °C, about 93 °C, about 94 °C, about 95 °C, about 96 °C, about 97 °C, about 98 °C, about 99 °C, or about 100 °C. In some embodiments, the temperature of the reaction mixture is at least about 25 °C, at least about 30 °C, at least about 35 °C, at least about 40 °C, at least about 45 °C, at least about 50 °C, at least about 55 °C, at least about 60 °C, at least about 65 °C, at least about 70 °C, at least about 75 °C, at least about 80 °C, at least about 85 °C, at least about 90 °C, at least about 95 °C, at least about 100 °C, at least about 105 °C, at least about 110 °C, at least about 115 °C, at least about 120 °C, at least about 125 °C, at least about 130 °C, at least about 135 °C, at least about 140 °C, at least about 145 °C, or at least about 150 °C. In some embodiments, the temperature of the reaction mixture is at most about 25 °C, at most about 30 °C, at most about 35 °C, at most about 40 °C, at most about 45 °C, at most about 50 °C, at most about 55 °C, at most about 60 °C, at most about 65 °C, at most about 70 °C, at most about 75 °C, at most about 80 °C, at most about 85 °C, at most about 90 °C, at most about 95 °C, at most about 100 °C, at most about 105 °C, at most about 110 °C, at most about 115 °C, at most about 120 °C, at most about 125 °C, at most about 130 °C, at most about 135 °C, at most about 140 °C, at most about 145 °C, or at most about 150 °C.

[0079] In some embodiments, the depolymerization is conducted at atmospheric pressure. In some embodiments, the depolymerization is conducted at elevated pressures. In some embodiments, thedepolymerization is conducted at a pressure of at least 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, or 10,000 kPa. In some embodiments, the depolymerization is conducted at a pressure of at most 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, or 10,000 kPa. In some embodiments, the depolymerization is conducted at a pressure from about atmospheric pressure to about 1517 kPa (220 psi), or from about atmospheric pressure to about 1378 kPa (200 psi), or from about atmospheric pressure to about 1034 kPa (150 psi), or from about atmospheric pressure to about 689 kPa (100 psi), or from about atmospheric pressure to about 344 kPa (50 psi), or from about 138 kPa (20 psi) to about 1034 kPa (150 psi), or from about 344 kPa (50 psi) to about 689 kPa (100 psi). In some embodiments, the depolymerization is conducted at about 97 kPa (14 psi), about 103 kPa (15 psi), about 110 kPa (16 psi), about 117 kPa (17 psi), about 124 kPa (18 psi), about 131 kPa (19 psi), about 138 kPa (20 psi), about 207 kPa (30 psi), about 276 kPa (40 psi), about 344 kPa (50 psi), about 414 kPa (60 psi), about 483 kPa (70 psi), about 552 kPa (80 psi), about 621 kPa (90 psi), about 689 kPa (100 psi), about 758 kPa (110 psi), about 827 kPa (120 psi), about 896 kPa (130 psi), about 965 kPa (140 psi), about 1034 kPa (150 psi), about 1103 kPa (160 psi), about 1172 kPa (170 psi), about 1241 kPa (180 psi), about 1310 kPa (190 psi), about 1379 kPa (200 psi), about 1448 kPa (210 psi), or about 1517 kPa (220 psi).

[0080] In some cases, a polyester can be depolymerized by using alcohol as a reagent and an alkoxide as a catalyst. FIG. 1A shows an example reaction scheme for the depolymerization of a polyester catalyzed by an alkoxide that consumes alcohol in the process. Ester bonds in the polyester can be broken such that the R2 group of the alcohol can be appended to the broken ester functional group and the alcohol functional group can be appended to the opposing end of the broken ester bond. The reaction can produce an ester derivative. FIG. IB shows an example reaction scheme for the depolymerization of a terephthalate polyester catalyzed by an alkoxide that consumes alcohol in the process. Ester bonds in the polyester can be broken such that the R2 group of the alcohol can be appended to the broken ester functional group and the alcohol functional group can be appended to the opposing end of the broken ester bond. The reaction can produce an ester derivative and a glycol.

[0081] In some cases, a polyester can be polymerized from an ester derivative. There is a selection of various reaction schema that can be followed to polymerize an ester derivative into a polyester. One possible pathway, for the case of terephthalate polyesters, is shown in FIG. 2. A diester can be reacted with a glycol using a catalyst (e.g., an antimony compound), to create the terephthalate polyester. Other possibilities may include converting the diester to a terephthalate (e.g., byhydrolysis), and then polymerizing the terephthalate and the glycol into the polyester while outputting water as a byproduct.

[0082] In some embodiments, the ester derivative contains less than about 10% impurity (w / w). In some embodiments, the ester derivative contains less than about 9% impurity (w / w). In some embodiments, the ester derivative contains less than about 8% impurity (w / w). In some embodiments, the ester derivative contains less than about 7% impurity (w / w). In some embodiments, the ester derivative contains less than about 6% impurity (w / w). In some embodiments, the ester derivative contains less than about 5% impurity (w / w). In some embodiments, the ester derivative contains less than about 4% impurity (w / w). In some embodiments, the ester derivative contains less than about 3% impurity (w / w). In some embodiments, the ester derivative contains less than about 2% impurity (w / w). In some embodiments, the ester derivative contains less than about 1% impurity (w / w). In some embodiments, the ester derivative contains less than about 0.5% impurity (w / w). In some embodiments, the ester derivative contains less than about 0.4% impurity (w / w). In some embodiments, the ester derivative contains less than about 0.3% impurity (w / w). In some embodiments, the ester derivative contains less than about 0.2% impurity (w / w). In some embodiments, the ester derivative contains less than about 0.1% impurity (w / w).

[0083] In some embodiments, the ester derivative contains less than about 250 ppm of any metals, less than about 240 ppm of any metals, less than about 230 ppm of any metals, less than about 220 ppm of any metals, less than about 210 ppm of any metals, less than about 200 ppm of any metals, less than about 190 ppm of any metals, less than about 180 ppm of any metals, less than about 170 ppm of any metals, less than about 160 ppm of any metals, less than about 150 ppm of any metals, less than about 140 ppm of any metals, less than about 130 ppm of any metals, less than about 120 ppm of any metals, less than about 110 ppm of any metals, less than about 100 ppm of any metals, less than about 90 ppm of any metals, less than about 80 ppm of any metals, less than about 70 ppm of any metals, less than about 60 ppm of any metals, less than about 50 ppm of any metals, less than about 40 ppm of any metals, less than about 30 ppm of any metals, less than about 20 ppm of any metals, less than about 10 ppm of any metals, less than about 5 ppm of any metals, less than about 4 ppm of any metals, less than about 3 ppm of any metals, less than about 2 ppm of any metals, less than about 1 ppm of any metals, less than about 0.9 ppm of any metals, less than about 0.8 ppm of any metals, less than about 0.7 ppm of any metals, less than about 0.6 ppm of any metals, less than about 0.5 ppm of any metals, less than about 0.4 ppm of any metals, less than about 0.3 ppm of any metals, less than about 0.2 ppm of any metals, less than about 0.1 ppm of any metals, less than about 0.09 ppm of any metals, less than about 0.08 ppm of any metals, less thanabout 0.07 ppm of any metals, less than about 0.06 ppm of any metals, less than about 0.05 ppm of any metals, less than about 0.04 ppm of any metals, less than about 0.03 ppm of any metals, less than about 0.02 ppm of any metals, or less than about 0.01 ppm of any metals.

[0084] In some cases, the depolymerization process may be performed at a location that is adjacent to a location that a polymerization process is performed. In some cases, monomers from the depolymerization process can be fed into the polymerization process. In some embodiments, a product or byproduct from the polymerization process can be fed into the depolymerization process. In some embodiments, the depolymerization process and the polymerization process are performed within 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, or 10,000 meters of one another.

[0085] In some embodiments, the depolymerization process is adjacent to an alcohol purification process. In some embodiments, the depolymerization process is adjacent to a terephthalate purification process. In some embodiments, the depolymerization process and the polymerization process are fluidically coupled.Ester Derivative Purification

[0086] In some aspects, the present disclosure provides a separation process for purifying an ester derivative. The separation process can comprise heating a mixture comprising the (i) an ester derivative in a solid phase and (ii) an alcohol to melt / dissolve the ester derivative. The separation process can comprise flash evaporating the mixture to evaporate the alcohol from the mixture. The separation process can comprise distilling the mixture to produce a distillate. The distillate can comprise a higher fraction of the ester derivative than the mixture. The separation process can comprise producing ester derivative flakes.

[0087] In some aspects, the present disclosure provides a separation process for purifying a terephthalate. The separation process can comprise heating a mixture comprising the (i) a terephthalate in a solid phase and (ii) an alcohol to melt / dissolve the terephthalate. The separation process can comprise flash evaporating the mixture to evaporate the alcohol from the mixture. The separation process can comprise distilling the mixture to produce a distillate. The distillate can comprise a higher fraction of the terephthalate than the mixture. The separation process can comprise producing terephthalate flakes.Alcohol and Glycol Purification: Acid Neutralization

[0088] In some aspects, the present disclosure provides a separation process for purifying an alcohol, e.g., a mono-alcohol, and a diol. The separation process can comprise providing a mixture comprising (i) a mono-alcohol and (ii) a diol. The mixture can comprise an alkoxide. The separation process can comprise adding an acid to the mixture. The separation process cancomprise distilling the mixture to produce a distillate comprising an increased ratio of the monoalcohol to the diol compared to the mixture. The separation process can comprise distilling the mixture to produce a bottom comprising an increased ratio of the diol to the mono-alcohol compared to the mixture.

[0089] A number of distillation columns can be used. In some embodiments, there can be at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more distillation columns. In some embodiments, there can be at most 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 distillation columns. In some embodiments, the distilling comprises distilling the mixture using a first distillation column to produce the distillate and a first intermediate composition. In some embodiments, the distilling comprises distilling the first intermediate composition using a second distillation column to produce a second intermediate composition and a waste bottom. In some embodiments, the distilling comprises distilling the second intermediate composition using a third distillation column to produce a waste distillate and the bottoms.Polyesters and Ester Derivatives

[0090] Polyester can refer to a category of polymers that contain the ester functional group in every repeat unit of their main chain. The polyester can react with an alcohol to break ester bonds that link one repeat unit to another to produce monomers that are terminated by the alkyl group of the alcohol.

[0091] A polyester can comprise: polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene sebacate), poly(ethylene adipate), poly(ethylene isophthalate), poly(ethylene phthalate), poly(butylene sebacate), poly(butylene succinate), poly(hexylene sebacate), polyhydroxybutyrate, polyethylene naphthalate, polyglycolide, polyglycolide or polyglycolic acid, polylactic acid, polycaprolactone, poly(Bisphenol A isophthalate), poly(Bisphenol A terephthalate), poly(ethylene glycol-co-l,4-cyclohexanedimethanol terephthalate), poly(3-hydroxybutyrate-co-3 -hydroxy valerate), polyester of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid, Vectran®, cutin, or any combination thereof.

[0092] Cutin can refer to one of two waxy polymers that are the main components of the plant cuticle, which covers all aerial surfaces of plants. Cutin comprises omega hydroxy acids and their derivatives, which can be interlinked via ester bonds to form a polyester polymer. There are two major monomer families of cutin, the C16 and Cl 8 families. The C16 family comprises mainly of 16-hydroxy palmitic acid and 9,16- or 10,16-dihydroxypalmitic acid. The C18 family comprises mainly of 18-hydroxy oleic acid, 9,10-epoxy-18-hydroxy stearic acid, and 9,10,18- trihydroxystearate. Tomato cutin comprises 16-hydroxy palmitic acid and 10,16-dihydroxypalmitic acid where the 10-isomer is largely dominant. The tomato cutin comprises a polyester biopolymerinteresterificated. The significant proportion of secondary esters (esterification in the C-10 secondary hydroxyl) shows that the polyester structure can be significantly branched.

[0093] In some embodiments, the polyester is polyglycolide or polyglycolic acid (PGA) and the ester derivative is a 2-hydroxyacetate derivative. In some embodiments, the ester derivative is methyl 2-hydroxyacetate.

[0094] In some embodiments, the polyester is polylactic acid (PLA) and the ester derivative is a 2- hydroxypropanoate derivative. In some embodiments, the ester derivative is methyl 2- hydroxypropanoate.

[0095] In some embodiments, the polyester is polycaprolactone (PCL) and the ester derivative is a 6-hydroxyhexanoate derivative. In some embodiments, the ester derivative is a methyl 6- hydroxyhexanoate.

[0096] In some embodiments, the polyester is polyhydroxybutyrate (PHB) and the ester derivative is a hydroxybutyrate derivative. In some embodiments, the ester derivative is methyl hydroxybutyrate.

[0097] In some embodiments, the polyester is polyethylene adipate (PEA) and the ester derivative is an adipate derivative. In some embodiments, the ester derivative is dimethyl adipate.

[0098] In some embodiments, the polyester is polybutylene succinate (PBS) and the ester derivative is a succinate derivative. In some embodiments, the ester derivative is dimethyl succinate.

[0099] In some embodiments, the polyester is poly(3-hydroxybutyrate-co-3 -hydroxy valerate) (PHBV) and the ester derivative is a hydroxybutyrate derivative, a hydroxyvalerate derivative, or a combination thereof. In some embodiments, the ester derivative is methyl hydroxybutyrate, methyl hydroxyvalerate, or a combination thereof.

[0100] In some embodiments, the polyester is polyethylene naphthalate (PEN) and the ester derivative is a naphthalate derivative. In some embodiments, the ester derivative is dimethyl naphthalate.

[0101] In some embodiments, the polyester is vectran and the ester derivative is a naphthoate derivative, a benzoate derivative, or a combination thereof. In some embodiments, the ester derivative is methyl hydroxynaphthoate or methyl hydroxybenzoate.

[0102] In some embodiments, the polyester is cutin and the ester derivative is a hydroxypalmitate or a dihydroxypalmitate derivative. In some embodiments, the ester derivative is methyl hydroxypalmitate or methyl dihydroxypalmitate.

[0103] In some embodiments, the polyester is polyethylene terephthalate (PET), polyethylene glycol-co-l,4-cyclohexanedimethanol terephthalate) (PETG), polytrimethyleneterephthalate (PTT), or polybutylene terephthalate (PBT) and the ester derivative is a terephthalate derivative. In some embodiments, the terephthalate derivative is a compound of formula (I):Formula (I); wherein R1and R2are independently selected from hydrogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce hydroxyalkyl, optionally substituted C3-C8 cycloalkyl, optionally substituted (Ci-Ce alkyl)(C3-Cs cycloalkyl), optionally substituted aryl, and optionally substituted (Ci-Ce alkyl)(aryl); provided that one of R1 or R2 is not hydrogen.

[0104] In some embodiments of a compound of Formula (I), R1and R2are independently Ci-Ce alkyl or Ci-Ce hydroxy alkyl.

[0105] In some embodiments of a compound of Formula (I), R1and R2are independently Ci-Ce alkyl. In some embodiments of a compound of Formula (I), R1and R2are independently methyl, ethyl, propyl, isopropyl, or butyl. In some embodiments of a compound of Formula (I), R1and R2are independently methyl or ethyl. In some embodiments of a compound of Formula (I), R1and R2are methyl. In some embodiments of a compound of Formula (I), R1and R2are ethyl. In some embodiments of a compound of Formula (I), R1and R2are not hydrogen.

[0106] In some embodiments of a compound of Formula (I), R1and R2are independently Ci-Ce hydroxyalkyl. In some embodiments of a compound of Formula (I), R1and R2are independently hydroxy ethyl or propanediol. In some embodiments of a compound of Formula (I), R1and R2are hydroxy ethyl. In some embodiments of a compound of Formula (I), R1and R2are 2- hydroxy ethyl. In some embodiments of a compound of Formula (I), R1and R2are dihydroxypropyl. In some embodiments of a compound of Formula (I), R1and R2are 2,3- dihydroxypropyl.

[0107] In some embodiments of a compound of Formula (I), R1and R2are independently optionally substituted (Ci-Ce alkyl)(C3-Cs cycloalkyl). In some embodiments of a compound of Formula (I), R1and R2are independently substituted (Ci-Ce alkyl)(C3-Cs cycloalkyl). In some embodiments of a compound of Formula (I), R1and R2are 4-(hydroxymethyl)cyclohexyl)methyl.

[0108] In some embodiments of a compound of Formula (I), R1and R2are independently optionally substituted aryl. In some embodiments of a compound of Formula (I), R1and R2are phenyl.

[0109] In some embodiments of a compound of Formula (I), R1and R2are independently optionally substituted (Ci-Ce alkyl)(aryl). In some embodiments of a compound of Formula (I), R1and R2are benzyl.

[0110] The polyester can comprise a homopolymer, a copolymer, a random copolymer, a block copolymer, an alternative copolymer, a copolymer with regular repeating units, or any combination thereof. The polyester can comprise polar monomers, nonpolar monomers, protic monomers, aprotic monomers, solvophobic monomers, solvophillic monomers, or any combination thereof. The polyester can comprise 1, 2, 3, 4, 5 or more types of monomers. The polyester can comprise linear topology, branched topology, star topology, dendritic topology, hyperbranched topology, bottlebrush topology, ring topology, catenated topology, or any combination thereof. The polyester can comprise 3 -armed topology, 4-armed topology, 5-armed topology, 6-armed topology, 7-armed topology, 8-armed topology, 9-armed topology, or 10-armed topology. The polyester can be entangled, or not entangled. The polyester can comprise oligomers below their entanglement molecular weight, or polymers above their entanglement molecular weight.

[0111] A polyester produced according to a system or a method disclosed herein can comprise high purity. The polyester can comprise at least about 99 wt%, at least about 99.1 wt%, at least about 99.2 wt%, at least about 99.3 wt%, at least about 99.4 wt%, at least about 99.5 wt%, at least about 99.6 wt%, at least about 99.7 wt%, at least about 99.8 wt%, at least about 99.9 wt% purity, at least about 99.91 wt% purity, at least about 99.92 wt% purity, at least about 99.93 wt% purity, at least about 99.94 wt% purity, at least about 99.95 wt% purity, at least about 99.96 wt% purity, at least about 99.97 wt% purity, at least about 99.98 wt% purity, or at least about 99.99 wt% purity. The polyester can comprise at most about 99 wt%, at most about 99.1 wt%, at most about 99.2 wt%, at most about 99.3 wt%, at most about 99.4 wt%, at most about 99.5 wt%, at most about 99.6 wt%, at most about 99.7 wt%, at most about 99.8 wt%, at most about 99.9 wt% purity, at most about 99.91 wt% purity, at most about 99.92 wt% purity, at most about 99.93 wt% purity, at most about 99.94 wt% purity, at most about 99.95 wt% purity, at most about 99.96 wt% purity, at most about 99.97 wt% purity, at most about 99.98 wt% purity, at most about 99.99 wt% purity, or at most about 100 wt% purity. The polyester can comprise less than 100 ppm, 10 ppm, 1 ppm, 100 ppb, or 10 ppb of impurities. The polyester can comprise greater than 100 ppm, 10 ppm, 1 ppm, 100 ppb, or 10 ppb of impurities.

[0112] A polyester produced according to a system or a method disclosed herein can recover polyester from a feedstock at a high yield. The polyester can comprise at least about 50 wt%, at least about 55 wt%, at least about 60 wt%, at least about 65 wt%, at least about 70 wt%, at least about 75 wt%, at least about 80, at least about 85 wt%, at least about 90 wt%, at least about 95 wt%, at least about 96 wt%, at least about 97 wt%, at least about 98 wt%, at least about 99 wt%, at least about 99.1 wt%, at least about 99.2 wt%, at least about 99.3 wt%, at least about 99.4 wt%, at least about 99.5 wt%, at least about 99.6 wt%, at least about 99.7 wt%, at least about 99.8 wt%, orat least about 99.9 wt% of polyester in the feedstock. The polyester can comprise at most about 50 wt%, at most about 55 wt%, at most about 60 wt%, at most about 65 wt%, at most about 70 wt%, at most about 75 wt%, at most about 80 wt%, at most about 85 wt%, at most about 90 wt%, at most about 95 wt%, at most about 96 wt%, at most about 97 wt%, at most about 98 wt%, at most about 99 wt%, at most about 99.1 wt%, at most about 99.2 wt%, at most about 99.3 wt%, at most about 99.4 wt%, at most about 99.5 wt%, at most about 99.6 wt%, at most about 99.7 wt%, at most about 99.8 wt%, or at most about 99.9 wt% of polyester in the feedstock.Alcohols

[0113] An alcohol can be a linear alcohol, branched alcohol, cyclic alcohol, polyol, or any combination thereof. An alcohol can comprise: methanol, ethanol, n-propanol, isopropanol, t- butanol, ( ?)-(-)-2 -butanol, (5)-(+)-2-butanol, isobutanol, ethylene glycol, glycerol, cyclopropanol, cyclobutanol, cyclopentanol, cyclohexanol, cycloheptanol, cyclohexane-l,4-diyldimethanol, phenol, benzyl alcohol, or any combination thereof.Glycols

[0114] A glycol can comprise: ethylene glycol, 1,2-propanediol, 1,3 -propanediol, 1,4- butanediol, 1,3 -butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3 -pentanediol, 1,4-pentanediol, 1,5- pentanediol, 2,3 -pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3 -hexanediol, 1,4-hexanediol, 1,5- hexanediol, 1,6-hexanediol, 2,3 -hexanediol, 2,4-hexanediol, 2,5-hexanediol, 3,4-hexanediol, Bisphenol A, or any combination thereof.

[0115] In some embodiments, the glycol is obtained in from about 80 to about 99 mol% yield. In some embodiments, the glycol is obtained in from about 85 to about 99 mol% yield. In some embodiments, the glycol is obtained in from about 90 to about 99 mol% yield. In some embodiments, the glycol is obtained in at least about 80 mol% yield. In some embodiments, the glycol is obtained in at least about 85 mol% yield.

[0116] In some embodiments, the glycol contains less than about 10% impurity (w / w). In some embodiments, the glycol contains less than about 9% impurity (w / w). In some embodiments, the glycol contains less than about 8% impurity (w / w). In some embodiments, the glycol contains less than about 7% impurity (w / w). In some embodiments, the glycol contains less than about 6% impurity (w / w). In some embodiments, the glycol contains less than about 5% impurity (w / w). In some embodiments, the glycol contains less than about 4% impurity (w / w). In some embodiments, the glycol contains less than about 3% impurity (w / w). In some embodiments, the glycol contains less than about 2% impurity (w / w). In some embodiments, the glycol contains less than about 1% impurity (w / w). In some embodiments, the glycol contains less than about 0.5% impurity (w / w). In some embodiments, the glycol contains less than about 0.4% impurity (w / w). In someembodiments, the glycol contains less than about 0.3% impurity (w / w). In some embodiments, the glycol contains less than about 0.2% impurity (w / w). In some embodiments, the glycol contains less than about 0.1% impurity (w / w).

[0117] In some embodiments, the glycol contains less than about 250 ppm of any metals, less than about 240 ppm of any metals, less than about 230 ppm of any metals, less than about 220 ppm of any metals, less than about 210 ppm of any metals, less than about 200 ppm of any metals, less than about 190 ppm of any metals, less than about 180 ppm of any metals, less than about 170 ppm of any metals, less than about 160 ppm of any metals, less than about 150 ppm of any metals, less than about 140 ppm of any metals, less than about 130 ppm of any metals, less than about 120 ppm of any metals, less than about 110 ppm of any metals, less than about 100 ppm of any metals, less than about 90 ppm of any metals, less than about 80 ppm of any metals, less than about 70 ppm of any metals, less than about 60 ppm of any metals, less than about 50 ppm of any metals, less than about 40 ppm of any metals, less than about 30 ppm of any metals, less than about 20 ppm of any metals, less than about 10 ppm of any metals, less than about 5 ppm of any metals, less than about 4 ppm of any metals, less than about 3 ppm of any metals, less than about 2 ppm of any metals, less than about 1 ppm of any metals, less than about 0.9 ppm of any metals, less than about 0.8 ppm of any metals, less than about 0.7 ppm of any metals, less than about 0.6 ppm of any metals, less than about 0.5 ppm of any metals, less than about 0.4 ppm of any metals, less than about 0.3 ppm of any metals, less than about 0.2 ppm of any metals, less than about 0.1 ppm of any metals, less than about 0.09 ppm of any metals, less than about 0.08 ppm of any metals, less than about 0.07 ppm of any metals, less than about 0.06 ppm of any metals, less than about 0.05 ppm of any metals, less than about 0.04 ppm of any metals, less than about 0.03 ppm of any metals, less than about 0.02 ppm of any metals, or less than about 0.01 ppm of any metals.Acids

[0118] An acid can comprise: sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, phosphorous acid, carbonic acid, acetic acid, perchloric acid, chloric acid, chlorous acid, hypochlorous acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, or any combination thereof.Depolymerization Catalysts

[0119] In some cases, the depolymerization stage uses a catalyst. The catalyst can comprise an alkoxide. The alkoxide can comprise a metal alkoxide. The alkoxide can comprise: a methoxide, an ethoxide, an n-propoxide, an n-butoxide, a t-butoxide, a sec-butoxide, an iso-butoxide, an iso-propoxide, or any combination thereof. The metal alkoxide can comprise a cation selected from the group consisting of: lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, ammonium, and any combination thereof.

[0120] The catalyst can comprise a glycoxide. The glycoxide can comprise a metal glycoxide. The metal glycoxide can comprise a cation selected from the group consisting of: lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, ammonium, and any combination thereof.

[0121] In some embodiments, the alkoxide, which comprises an alkoxide anion and a cation is selected from an alkali metal alkoxide, an alkaline earth metal alkoxide, a metal alkoxide, an ammonium alkoxide, and any combinations thereof. In some embodiments, the alkoxide anion is a C1-C4 alkoxide anion. In some embodiments, the alkoxide anion is selected from methoxide, ethoxide, n-propoxide, n-butoxide, t-butoxide, sec-butoxide, iso-butoxide, iso-propoxide, and a combination thereof. In some embodiments, the alkoxide anion is methoxide, ethoxide, or any combinations thereof. In some embodiments, the alkoxide anion is methoxide. In some embodiments, the cation is lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, or ammonium. In some embodiments, the alkoxide is sodium methoxide, potassium ethoxide, or aluminum tri-n-propoxide. In some embodiments, the ammonium alkoxide is a tetraalkylammonium alkoxide. In some embodiments, the ammonium alkoxide is a tetrabutylammonium alkoxide. In some embodiments, the alkoxide is sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, or tetrabutylammonium methoxide.

[0122] In some embodiments, the alkoxide is generated in-situ by addition of an alkali metal, an alkaline earth metal, or a metal to the alcoholic solvent.

[0123] In some embodiments, the ratio of polyester to alkoxide is from about 15: 1 to about 125: 1 (w:w), or from about 15: 1 to about 100: 1 (w:w), or from about 15: 1 to about 80: 1 (w:w), or from about 15: 1 to about 60: 1 (w:w), or from about 15: 1 to about 40: 1 (w:w), or from about 15: 1 to about 25: 1 (w:w), or from about 15: 1 to about 20: 1 (w:w), or from about 20: 1 to about 25: 1 (w:w), or from about 20: 1 to about 50: 1 (w:w), or from about 30: 1 to about 60: 1 (w:w), or from about 40: 1 to about 70: 1 (w:w), or from about 50: 1 to about 80: 1 (w:w), or from about 60: 1 to about 90: 1 (w:w), or from about 20: 1 to about 125: 1 (w:w), or from about 40: 1 to about 125: 1 (w:w), or from about 60: 1 to about 125: 1 (w:w), or from about 80: 1 to about 125: 1 (w:w), or from about 100: 1 to about 125: 1 (w:w). In some embodiments, the ratio of polyester to alkoxide is from about 20: 1 to about 25: 1 (w:w).Certain Terminology

[0124] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0125] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood to which the claimed subject matter belongs. In the event that there are a plurality of definitions for terms herein, those in this section prevail.

[0126] It is to be understood that the general description and the detailed description are exemplary and explanatory only and are not restrictive of any subject matter claimed. In this application, the use of the singular includes the plural unless specifically stated otherwise. It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. In this application, the use of “or” means “and / or” unless stated otherwise. Furthermore, use of the term “including” as well as other forms, such as “include”, “includes,” and “included,” is not limiting.

[0127] Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.” Further, headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed invention.

[0128] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0129] As used herein, the term “about” or “approximately” means within 10%, preferably within 10%, and more preferably within 5% of a given value or range.

[0130] As used herein, ambient temperature is a colloquial expression for the typical or preferred indoor (climate-controlled) temperature to which people are generally accustomed. It represents the small range of temperatures at which the air feels neither hot nor cold, approximately 21 °C. In some embodiments, ambient temperature is 25±5 °C. In some embodiments, ambient temperature is 18 °C. In some embodiments, ambient temperature is 19 °C. In some embodiments, ambient temperature is 20 °C. In some embodiments, ambient temperature is 21 °C. In some embodiments, ambient temperature is 22 °C. In some embodiments, ambient temperature is 23 °C. In some embodiments, ambient temperature is 24 °C. In some embodiments, ambient temperature is 25 °C. In some embodiments, ambient temperature is 26 °C. In some embodiments, ambienttemperature is 27 °C. In some embodiments, ambient temperature is 28 °C. In some embodiments, ambient temperature is 29 °C. In some embodiments, ambient temperature is 30 °C.

[0131] As used in this specification and the appended claims, depolymerization, refer to a way of breaking down a polymer to its starting material. It is essentially the opposite of polymerization. In some embodiments, the depolymerization is achieved by glycolysis, methanolysis or hydrolysis, categorized by the depolymerization reactant used, such as glycol, methanol or water, respectively.

[0132] Definition of standard chemistry terms may be found in reference works, including but not limited to, Carey and Sundberg “Advanced Organic Chemistry 4th Ed.” Vols. A (2000) and B (2001), Plenum Press, New York.

[0133] The terms below, as used herein, have the following meanings, unless indicated otherwise:

[0134] “Alkyl” refers to a straight or branched hydrocarbon chain radical which is attached to the rest of the molecule by a single bond. A linear alkyl comprising up to 4 carbon atoms is referred to as a linear C1-C4 alkyl, likewise, for example, a linear alkyl comprising up to 3 carbon atoms is a linear C1-C3 alkyl. Linear alkyl groups include linear C1-C4 alkyl, linear C1-C3 alkyl, linear C1-C2 alkyl, linear C2-C3 alkyl and linear C2-C4 alkyl. Representative alkyl groups include, methyl, ethyl, propyl, and butyl. A branched alkyl comprising between 3 and 4 carbon atoms is referred to as a branched C3-C4 alkyl. Representative branched alkyl groups include, but are not limited to t-butyl, sec-butyl, isobutyl, and isopropyl. Unless stated otherwise specifically in the specification, an alkyl is optionally substituted with oxo, halogen, -CN, -CF3, OH, -OMe, NH2, or -NO2. In some embodiments, an alkyl is optionally substituted with oxo, halogen, -CN, -CF3, OH, or -OMe. In some embodiments, the alkyl is optionally substituted with halogen.

[0135] “Halo” or “halogen” refers to bromo, chloro, fluoro or iodo. In some embodiments, halogen is fluoro or chloro. In some embodiments, halogen is fluoro.

[0136] “Haloalkyl” refers to an alkyl radical, as defined above, that is substituted by one or more halo atoms, as defined above, e.g., trifluoromethyl, difluoromethyl, fluoromethyl, tri chloromethyl, 2,2,2 trifluoroethyl, 1,2 difluoroethyl, 3 bromo 2 fluoropropyl, 1,2 dibromoethyl, and the like.

[0137] “Hydroxyalkyl” refers to an alkyl radical, as defined above, that is substituted by one or more -OH groups, e.g., hydroxymethyl, hydroxyethyl, hydroxypropyl, propanediol, and the like.

[0138] “Cycloalkyl” refers to a stable, partially or fully saturated, monocyclic or polycyclic carbocyclic ring, which may include fused or bridged ring systems. Representative cycloalkylsinclude, but are not limited to, cycloalkyls having from three to fifteen carbon atoms (C3-C15 cycloalkyl), from three to ten carbon atoms (C3-C10 cycloalkyl), from three to eight carbon atoms (C3-C8 cycloalkyl), from three to six carbon atoms (C3-C6 cycloalkyl), from three to five carbon atoms (C3-C5 cycloalkyl), or three to four carbon atoms (C3-C4 cycloalkyl). In some embodiments, the cycloalkyl is a 3- to 6-membered cycloalkyl. In some embodiments, the cycloalkyl is a 5- to 6- membered cycloalkyl. Monocyclic cycloalkyls include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Polycyclic cycloalkyls or carbocycles include, for example, adamantyl, norbornyl, decalinyl, bicyclo[3.3.0]octane, bicyclo[4.3.0]nonane, cis decalin, trans decalin, bicyclo[2.1.1]hexane, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, bicyclo[3.2.2]nonane, and bicyclo[3.3.2]decane, and 7,7 dimethyl bicyclo[2.2.1]heptanyl. Partially saturated cycloalkyls include, for example cyclopentenyl, cyclohexenyl, cycloheptenyl, and cyclooctenyl. Unless stated otherwise specifically in the specification, a cycloalkyl is optionally substituted with oxo, halogen, methyl, ethyl, -CN, -CF3, OH, -OMe, NH2, or -NO2. In some embodiments, a cycloalkyl is optionally substituted with oxo, halogen, methyl, ethyl, -CN, -CF3, OH, or -OMe. In some embodiments, the cycloalkyl is optionally substituted with halogen.

[0139] “Aryl” refers to a radical derived from a hydrocarbon ring system comprising hydrogen, 6 to 30 carbon atoms and at least one aromatic ring. The aryl radical may be a monocyclic, bicyclic, tricyclic or tetracyclic ring system, which may include fused or bridged ring systems. In some embodiments, the aryl is a 6- to 10-membered aryl. In some embodiments, the aryl is a 6-membered aryl. Aryl radicals include, but are not limited to, aryl radicals derived from the hydrocarbon ring systems of anthrylene, naphthylene, phenanthrylene, anthracene, azulene, benzene, chrysene, fluoranthene, fluorene, as-indacene, s indacene, indane, indene, naphthalene, phenalene, phenanthrene, pleiadene, pyrene, and triphenylene. In some embodiments, the aryl is phenyl. Unless stated otherwise specifically in the specification, an aryl may be optionally substituted, for example, with halogen, amino, nitrile, nitro, hydroxyl, alkyl, alkenyl, alkynyl, haloalkyl, alkoxy, aryl, cycloalkyl, heterocycloalkyl, heteroaryl, and the like. In some embodiments, an aryl is optionally substituted with halogen, methyl, ethyl, -CN, -CF3, OH, -OMe, NH2, or -NO2. In some embodiments, an aryl is optionally substituted with halogen, methyl, ethyl, - CN, -CF3, OH, or -OMe. In some embodiments, the aryl is optionally substituted with halogen.

[0140] As used herein, the term “mol” when referring to PET is the molar amount and is calculated using the molecular weight of the “PET” unit which is 192.17 g / mol.

[0141] As used herein, the terms “oligomer” or “r-PET oligomer” may refer to a polymeric species comprising from about 2 to about 50 repeating monomeric units. In some cases, the“oligomer” or “r-PET oligomer” may refer to a polymeric species having a molecular weight not exceeding 1,000 Daltons.

[0142] As used herein, the term “bottle grade” refers to a form of PET suitable for one or more of beverage containers, food packaging, and liquid storage containers.

[0143] As used herein, the term “fiber grade” or “textile grade” or filament grade” refers to a form of PET suitable for production of one or more of fibers, textiles, carpets, and filaments.

[0144] As used herein, the term “pharmaceutical grade” or “pharma grade” refers to a form of PET suitable for safely packaging pharmaceutical products.EXAMPLES

[0145] The following examples are provided to further illustrate some embodiments of the present disclosure, but are not intended to limit the scope of the disclosure; it will be understood by their exemplary nature that other procedures, methodologies, or techniques known to those skilled in the art may alternatively be used.Example 1: Polyethylene terephthalate depolymerization

[0146] Polyethylene terephthalate (1,000 g) was introduced in a reactor. Dichloromethane (500 g) was added and the mixture was stirred at room temperature and atmospheric pressure for about 40 minutes. Sodium methoxide and methanol were then added to the reaction mixture and the resulting mixture was stirred and heated for 120 minutes. Table 1 below shows reaction conditions and corresponding yields.

[0147] The mixture was then filtered and the filter cake was washed with methanol. The filter cake was then melted and filtered at 140 °C to remove any unreacted materials. The filtered dimethyl terephthalate was then distilled under vacuum at 200 °C. The liquid recovered from the filtration was distilled to recover the solvents and mono ethylene glycol (MEG).Table 1. Reaction conditions and corresponding yieldsExample 2: Recovery of Dimethyl Terephthalate from Polyethylene Terephthalate with Sodium Methoxide and Methanol

[0148] Polyethylene terephthalate (1,000 g) was introduced in a reactor. DMSO (500 g) was added and the mixture was stirred at room temperature and atmospheric pressure for about 40 minutes. Sodium methoxide (45 g) and methanol (550 g) were then added to the reaction mixture and the resulting mixture stirred and heated at 55 °C for 120 minutes.

[0149] The mixture was then filtered and the filter cake was washed with methanol. The filter cake was then melted and filtered at 140 °C to remove any unreacted materials. The filtered dimethyl terephthalate was then distilled under vacuum at 200 °C. The liquid recovered from the filtration was distilled to recover the solvents and mono ethylene glycol.

[0150] Dimethyl terephthalate (DMT) was obtained at 89% yield.Example 3: Recovery of Dimethyl Terephthalate and Mono Ethylene Glycol from Polyethylene Terephthalate with Sodium Methoxide and Methanol

[0151] PET (10,000 g) was treated with methanol (6,000 g) at 60 °C for an hour. The methanol was then drained. After draining, the reactor was heated up from 60 °C to 70 °C and sodium methoxide (at 25 wt% in methanol) was added. Thirty minutes after the sodium methoxide addition, the balance of methanol was added. The reaction was performed for 3 hours after the addition of sodium methoxide. The mixture was cooled at room temperature then filtered to separate MEG, sodium methoxide, and residual methanol from DMT and unreacted material. The filtration worked for trials 3 to 5 while trials 1 and 2 were unfilterable even with using different solid liquid separation methods (centrifugation, press filter, vacuum filter, or pressure filter). Since filtration was not possible, distillation of methanol followed with distillation of MEG and then distillation of DMT from the reactional mixture was tried in a rotary evaporator. After recovery of methanol, the mixture turned into a paste from where distillation of MEG and DMT was not possible due to side reactions with contaminants.

[0152] For trials 3 to 5, after solid-liquid separation. The residual methanol and MEG were recovered from the liquid phase into two different fractions using a rotary evaporator. DMT was successfully recovered from the solid phase using a thin film evaporator.Table 2. Recovery of DMT and MEG with varying amounts of sodium methoxide.1dimethyl terephthalate2mono ethylene glycol3The slurry was heated to try evaporating the DMT and the MEG but it wasn't possible due products generation mixed with all the contaminants.4Pure DMT was recovered from the cake that was exempt of MEG and catalyst. Pure MEG was recovered from the mother liquor and the washes that contained less than 1% DMT.Example 4: Process for Upcycling Polyethylene TerephthalatePreprocessing Stage

[0153] A preprocessing stage receives a feedstock of PET to dry the feedstock and feed it into the depolymerization stage.Depolymerization Stage

[0154] A depolymerization stage receives PET from the preprocessing stage. The PET enters two depolymerization reactors (RK-201 Ekato 1 and RK-202 Ekato 2) with the addition of sodium methoxide and methanol from a fresh source and a recycle source (i.e., from the vacuum belt filter system, FL-221). The reactors depolymerize PET into DMT and ethylene glycol.Phase Separation Stage

[0155] The output composition from the depolymerization stage, comprising DMT and ethylene glycol, is directed to a screener (VS-201) along with fresh methanol, which removes unreacted materials. A fraction is stored into a waste drum, and the remainder is directed to a buffer tank to to continuously feed the remainder into the vacuum belt filter.DMT-EG Separation Stage

[0156] A vacuum belt filter receives solid / liquid mixture from the buffer tank. DMT is mainly comprised in the solid fraction, and ethylene glycol is mainly comprised in the liquid fraction. The vacuum belt filter separates the liquid and solid fraction, and the solid fraction is washed multiple times with methanol. The wash liquid is stored into a wash tank, which is directed to the depolymerization reactor.DMT Puri fication Stage

[0157] The solid phase comprising DMT is directed to a heated tank (TK-304 DMT Melter) to melt it to liquid phase. The liquid phase is directed to a flash evaporator (FL-301). The gaseous fraction comprising mainly DMT is directed to a distillation column DT-301, while the remainder is sent to waste. The DMT is distilled to output a high purity distillate, which is solidified, and then flaked by a flaker FK-361. The bottoms of the distillation column is directed to waste.EG Puri fication Stage

[0158] The liquid phase from the filtration stage is directed to a stirred tank T-104. The composition is directed to a neutralization reactor with the addition of sulfuric acid to restore the composition towards an acdeic pH of about 3.8 at R-101. The feed tank stores the product before feeding into a distillation column. The composition is directed to a series of distillation columns to produce a distillate comprising mainly methanol, and a bottom product comprising mainly ethylene glycol. The methanol distillate is stored to be reused in other parts of the system.PET Polymerization Stage

[0159] DMT from the DMT Purification Stage, and ethylene glycol and methanol from the Ethylene Glycol Purification Stage are added to an ester exchange 04-R01 along with isopropyl alcohol and catalysts. The liquid fraction is directed to a PP Reactor to polymerize the monomers to make PET. The PET is cut into chips by a chip cutter 06-C01, and then the chips are directed to a SSP Reactor. The vapor fraction from the ester exchange reactor is directed to exchange colomns to generate ethylene glylcol and methanol.Example 5: Depolymerization of PET and Polyester Fiber Feedstocks with non-PET Contaminants

[0160] Various polyester feedstocks in flake form and fiber / textile form comprising varying amounts of contaminants by weight were subject to depolymerization and subsequent monomer purification steps as described in Example 3 and Example 4. The purity of the resulting recycled MEG (r-MEG) and recycled DMT (r-DMT) monomers were determined and are provided in Table 3. All recycled monomer samples recovered were free of initial feedstock contaminants after depolymerization and purification. Purity of r-MEG monomers were obtained usingTable 3. Compositional Analysis of Waste Feedstock and Recycled Monomer Purity(1)Indication of high densified material, reducing the access to PET.Example 6: Purity and Quality Assessment of r-DMT Monomers

[0161] Twenty-two recycled dimethyl terapthalate (r-DMT) samples were recovered following the depolymerization of various polyester feedstocks followed by terephthalate purification as described in Example 4 and subsequently analyzed to evaluate their purity and composition. A visual inspection of each sample indicated all samples presented as a white powder. To characterize the color of the r-DMT samples, a tristimulus colorimeter was used based on the L*a*b* color system (CIELAB). Values of L* were indicative of lightness ranging from 0 (black) to 100 (white), and a* and b* values were illustrative of color components on the green-red and blue-yellow axes, respectively. To further assess the purity of each sample, absorbance at 340 nanometers (A340) was measured and recorded for each sample. The melting point of each sample was also measured and recorded for each sample. High-performance Liquid Chromatography with Ultraviolet Detection (HLP-UV) was performed on each sample to detect and quantify by weight amounts of dimethyl terephthalate (DMT), as well as amounts of various impurities including dimethyl isophthalate (DMIP), l-(2-hydroxyethyl)4-methyl terephthalate (HEMT), and monomethyl terephthalate, present in each sample. The corresponding results from the analyses are provided in Table 4.Table 4. Quantitative Compositional Analysis of r-DMT Monomers

[0162] The presence of various elemental impurities including cadmium, lead, arsenic, cobalt, nickel, antimony, molybdenum, copper, tin, chromium, aluminum, iron, manganese, titanium, zinc, and mercury was also evaluated in each r-DMT sample using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), the results for which are presented in Table 5.Table 5. Elemental Impurity Analysis of r-DMT MonomersTable 5 (Continued)Example 7: Purity and Quality Assessment r-MEG Monomers

[0163] Fourteen recycled Monoethylene Glycol (r-MEG) monomer samples were recovered following depolymerization reactions of various polyester feedstocks as described in Example 2 and Example 3. A compositional analysis was performed on each sample to assess the quality and purity of each recycled monomer. First, a visual inspection was performed, confirming all samples tested presented as clear and transparent liquids. A color assessment of the r-MEG samples was performed using the APHA color scale. To further assess the purity of each sample, the boiling point of each sample was also measured. High-performance Liquid Chromatography with Ultraviolet Detection (HLP-UV) was performed on each sample to detect and quantify by weight amounts of dimethyl terephthalate (DMT), as well as amounts of various impurities including formaldehyde, acetaldehyde, DEG, neopenthyl glycol, 1,4-Cyclohexane dimethanol, DMT, DMI, 1- (2 -hydroxy ethyl) 4-methyl terephthalate, 1 -(2-hydroxyethyl)4-methyl isophthalate, monomethyl terephthalate, and BHET, present in each sample. The corresponding results from the analyses are provided in Table 6.Table 6. Quantitative Compositional Analysis of r-MEG MonomersTable 6 (Continued)ND = Not detected

[0164] The presence of various elemental impurities including cadmium, lead, arsenic, cobalt, nickel, antimony, molybdenum, copper, tin, chromium, aluminum, iron, manganese,titanium, zinc, and mercury was also evaluated in each r-MEG sample using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), the results for which are presented in Table 7.Table 7. Elemental Impurity Analysis of r-MEG MonomersTable 7. (Continued)Example 8: Storage Stability Analysis of r-DMT and r-MEG Monomers

[0165] An evaluation was carried out to assess the stability and shelf life of r-DMT and r- MEG monomers produced following a depolymerization process after varying durations under as shown in Table 8. All batches were kept at room temperature and humidity. The r-MEG was stored in 55-gallon polyethylene drums. The DMT was stored in poly-lined bulk bags.Table 8. Storage Duration of r-DMT and r-MEG Prior to Polymerization

[0166] The stored r-DMT and r-MEG monomers were subsequently subjected to a polymerization process to produce eleven recycled PET (r-PET) batches, six of which were assessed for conforming to bottle-grade PET specifications, and five of which were assessed for conforming to fiber-grade PET specifications. The results from the analysis are provided below in Table 9 and Table 10.Table 9. Quantitative Compositional Analysis of Bottle-Grade r-PET from r-DMT and r- MEG Following Varying Monomer Storage DurationsND = Not detectedTable 10. Quantitative Compositional Analysis of Fiber-Grade r-PET from r-DMT and r- MEG Following Varying Monomer Storage DurationsExample 8: System for Upcycling Polyester Feedstock Comprising Polyethylene Terephthalate

[0167] FIG. 7 provides an example process for an integrated PET upcycling and monomer recovery.Conditioning

[0168] A waste polyester feedstock comprising polyethylene terephthalate and / or polyester fiber is obtained for conditioning. The conditioning process steps are described in FIG. 8A, wherein a waste product is first subject to removal of metals via magnetic separation and removal of moisture via drying. The waste polyester feedstock is conveyed to a magnetic separator unit to remove metal contents from the waste polyester feedstock. The waste polyester feedstock is then dried using a drying unit at a temperature of about 130 °C.Depolymerization

[0169] A depolymerization stage receives the waste polyester feedstock from the conditioning stage. The conditioned feedstock is subject to the process shown in FIG. 8B, whereina depolymerization reactor vessel comprises the conditioned feedstock, methanol, and a depolymerization catalyst, which is then forms a depolymerization slurry. The conditioned waste polyester feedstock is fed into one or more depolymerization reactors and treated with methanol at a temperature not exceeding 100°C for a duration of 30 min to swell the polyester. Sodium methoxide (at 25 wt% in methanol) is added in a polyester to catalyst molar ratio from about 83 : 1 to about 10: 1 with the balance of methanol. The depolymerization reaction proceeds for a duration of from about 2 hours to about 3 hours hours following the addition of sodium methoxide at a temperature not exceeding 100°C. The pressure of the depolymerization reaction does not exceed 120 psi for the entire duration of the reaction. The depolymerization reaction occurs in an inert carrier gas layer (e.g., nitrogen) to prevent undesired side reactions.Phase Separation StageThe depolymerization slurry, is then cooled to room temperature and directed to one or more filtration units (e.g., batch filter, continuous filter, candle filter, rotary vacuum filter, parabolic screen filter, vibrating screen filter, pressure plate filter, etc) to separate MEG, sodium methoxide, residual methanol and DMT from unreacted material, the process for which is shown in FIG. 8B. DMT-EG Separation Stage

[0170] A subsequent filtration unit receives the filtered depolymerization slurry from the a storage tank. DMT is mainly comprised in the solid fraction, and ethylene glycol is mainly comprised in the liquid fraction, the process for which is shown in FIG. 7 and FIG. 8B. The filtration unit separates the liquid and solid fraction, and the solid fraction is washed multiple times with methanol. The wash liquid is stored into a wash tank, which is directed to the depolymerization reactor.DMT Puri fication Stage

[0171] As shown in FIG. 8C, the solid phase comprising DMT is directed to a heated tank to melt it to liquid phase and methanol contained in a gaseous phase is collected for use in other areas of the system. The liquid phase is directed to a distillation column, while the remainder is sent to waste. The DMT is distilled under an inert carrier gas to output a distillate, which is either stored in a DMT storage tank, or solidified, and then flaked by a flaker. The bottoms of the distillation column is directed to waste.MEG Puri fication Stage

[0172] As shown in FIG. 8D, the liquid phase from the filtration stage is directed to a mother liquor tank. The mother liquor is directed to a neutralization reactor with the addition of sulfuric acid. The neutralized solution is fed into a a first distillation column to produce a distillate comprising methanol. The methanol distillate is collected and stored to be reused in other parts ofthe system. The bottom from the first distillation column is directed to one or more subsequent distillation columns to produce a bottom product comprising mainly monoethylene glycol (MEG) from the final distillation. The ethylene glycol is stored in a tank for subsequent use.PET Polymerization Stage

[0173] As shown in FIG. 8E, DMT from the DMT Purification Stage, and ethylene glycol from the Ethylene Glycol Purification Stage are added to an ester exchange column to carry out a transesterification reaction to form r-PET. During this process, short chains of repeating units, or oligomers, are initially formed. The liquid fraction of the ester exchange column is directed a melt phase polycondensation unit outputting one or more vapor streams comprising monomers and oligomers formed during the transesterification reaction and pulled from the main r-PET product stream. The melt phase polycondensation unit produces recycled PET (r-PET) in an amorphous state having an intrinsic viscosity from about 0.40 dL / g to about 0.70 dL / g. A portion of the amorphous PET is suitable for use as fiber grade PET. A portion of the amorphous PET is directed to a solid state polymerization (SSP) unit, where the r-PET is crystallized, solid state polymerized, and cooled under an inert carrier gas layer. The crystalline r-PET has an intrinsic viscosity from about 0.70 dL / g to about 0.85 dL / g and is suitable for use as bottle-grade PET. The fiber grade r- PET and the bottle grade r-PET are subjected to analysis for quality and purity.DMT-EG Recovery Stage

[0174] As shown in FIG. 8F, The vapor streams are condensed and collected from the melt phase polycondensation phase of the polymerization stage to form a byproduct mixture collected in a tank. The byproduct mixture is partially evaporated evaporated into a gaseous phase comprising monoethylene glycol and a liquid phase for comprising r-PET oligomers. The r-PET oligomers and are directed to the depolymerization stage for recovery of additional DMT and MEG. The gaseous phase comprising monoethylene glycol undergoes a first separation to recover ethylene glycol in a first collection fraction and first waste fraction. The first collection fraction undergoes a second separation to recover ethylene glycol in a second collection fraction and waste in a second waste fraction. The second collection fraction comprising MEG is directed back to the polymerization stage for use. The second waste fraction is directed to the ethylene glycol purification stage to recover additional MEG for use in the polymerization stage.Example 9. Comparison of PET Produced by r-DMT and r-MEG with PET Produced by virgin DMT (v-DMT) and virgin MEG (v-MEG)

[0175] Ten tons of fiber-grade r-PET and ten tons of bottle-grade r-PET were generated from v-DMT, v-MEG, r-DMT, and r-MEG monomers, and subjected to analysis for purity andquality following an ester exchanger stage, a melt phase polycondensation stage, and a solid state polymerization stage of a polymerization process. Each batch was assessed with respect to reaction cycle time and peak temperature following the ester exchange phase and following the melt phase polycondensation phase. Following the melt phase polycondensation stage and the solid state polymerization phase of each batch, quality was assessed with respect to intrinsic viscosity (IV), melting point, and acetate ion content. A color assessment of the v-PET and r-PET L*a*b color scale as described in Example 6. The results for the cycle time, peak temperature, and quality assessments for each batch are shown below in Tables 11-17.Table 11. Cycle Time and Peak Temperature Assessment of v-DMT and v-MEG for Bottle- Grade v-PETTable 12: Cycle Time and Peak Temperature Assessment of r-DMT and r-MEG for Bottle-Grade r-PETTable 13: Cycle Time and Peak Temperature Assessment of r-DMT and r-MEG for Fiber-Grade v-PETTable 14: Quality Assessment of Bottle Grade v-PET after Melt Phase PolycondensationTable 15. Quality Assessment of Fiber Grade r-PET (from r-DMT and r-MEG) after Melt Phase PolycondensationTable 16. Quality Assessment of Bottle Grade v-PET (from v-DMT and v-MEG) after Solid State PolymerizationTable 17. Quality Assessment of Bottle Grade r-PET (from r-DMT and r-MEG) after Solid State Polymerization

[0176] While preferred embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. It should be understood that various alternatives to the embodiments of the present disclosure may be employed in practicing the present disclosure. It is intended that the following claims define the scope of the present disclosure and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

CLAIMSWhat is claimed is:

1. A system for producing polyester, the system comprising:(a) a depolymerization module configured to receive a first alcohol and a first polyester in a first composition to form a second composition comprising a glycol and a terephthalate;(b) a separation module configured to separate the terephthalate from the glycol; and(c) a polymerization module configured to receive the terephthalate and the glycol to form a third composition comprising a second polyester and a second alcohol; wherein the first alcohol used in the depolymerization module comprises at least a portion of the second alcohol formed in the polymerization module.2 The system of claim 1, wherein the separation module comprises a filtration module, and wherein the filtration module is a belt filter, a screw press, or a filter press, or a combination thereof.3 The system of claim 2, wherein the separation module further comprises one or more screeners configured to remove a solid waste, and wherein the screener is upstream of the filtration module.4 The system of claim 2, wherein the screener is a vibrating screen filter, a trommel screen filter, a rotating screen filter, a sieve filter, a decanting screen filter, or a combination thereof.5 The system of claim 1, further comprising a glycol recovery module configured to receive a mixture comprising glycol byproduct from the polymerization module, wherein the glycol recovery module comprises an evaporator column and at least one separation column downstream of the evaporator column, thereby producing recycled glycol.6 The system of claim 4, wherein the polymerization module in (c) is further configured to receive the recycled glycol to form the third composition.7 The system of any one of claims 1-4, further comprising a glycol recovery module configured to receive a mixture comprising glycol byproduct from the polymerization module, wherein the glycol recovery module comprises an evaporator column and at least one separation column downstream of the evaporator column.8 The system of claim 7, wherein the polymerization module in (c) is further configured to receive the recycled glycol to form the third composition.9 The system of any one of claims 1-8, wherein the first alcohol and the second alcohol is methanol.10 The system of any one of claims 1-9, wherein the glycol is monoethylene glycol (MEG).

11. A method for upcy cling a polyester comprising a first purity, the method comprising upcycling the polyester to produce a second polyester, wherein the second polyester comprises a second purity equal to or greater than the first purity, and wherein the second polyester comprises at least 70 wt% of the polyester.

12. The method of claim 11, wherein the upcycling comprises depolymerizing the polyester and polymerizing the second polyester.

13. The method of claim 11, wherein the second polyester comprises form about 75 wt% to about 99.5 wt% of the polyester.

14. A waste polyester feedstock conditioning system, comprising:(a) a feedstock collection vessel configured to receive a waste product comprising polyethylene terephthalate (PET);(b) a magnetic separator unit configured to reduce a metal content from the waste product to no greater than 2 w / w%; and(c) a drying unit configured to dry the waste product to reduce a water content to no greater than 500 ppm; wherein the waste polyester feedstock conditioning system is upstream of a depolymerization system and is configured to produce a waste polyester feedstock, and wherein the waste polyester feedstock comprises from about 0.5 w / w% to about 25 w / w% non-PET contaminants, and wherein the conditioning system does not comprise a module configured to melt the waste product or the waste polyester feedstock.

15. A PET depolymerization system comprising:(a) one or more depolymerization reactor vessels configured to: i. receive a reaction mixture comprising a waste polyester feedstock, an alcoholic solvent, and a depolymerization catalyst; and ii. carry out an alcoholysis reaction on the reaction mixture to form a depolymerization slurry;(b) one or more filtration units configured to separate the depolymerization slurry into a solid fraction and a liquid fraction; and(c) one or more separation modules configured to recover and recycle the alcoholic solvent, wherein the waste polyester feedstock comprises polyethylene terephthalate (PET) and from about 0.5 w / w% to about 25 w / w% non-PET contaminants, and wherein the alcoholysis reaction is carried out at a temperature not exceeding 100 °C.

16. A PET depolymerization system comprising:(a) one or more depolymerization reactor vessels configured to: i. receive a reaction mixture comprising a waste polyester feedstock, an alcoholic solvent, and a depolymerization catalyst; and ii. carry out an alcoholysis reaction on the reaction mixture to form a depolymerization slurry;(b) one or more filtration units configured to separate the depolymerization slurry into a solid fraction and a liquid fraction; and(c) one or more separation modules configured to recover and recycle the alcoholic solvent, wherein the waste polyester feedstock comprises polyethylene terephthalate (PET) and from about 0.5 w / w% to about 25 w / w% non-PET contaminants, and wherein the alcoholysis reaction is carried out at a pressure not exceeding 120 psi.

17. A glycol purification system comprising:(a) a neutralization unit configured to react a liquid fraction comprising glycol with an acid to form a neutralized mixture;(b) a first distillation unit configured to distill and recover methanol distillate from the neutralized mixture and a first bottom; and(c) one or more subsequent distillation units configured to distill and recover glycol from the first bottom, wherein the glycol purification system is downstream of a depolymerization system.

18. The glycol purification system of claim 17, wherein the glycol purification system is fluidically coupled with a polymerization system.

19. The glycol purification system of claim 18, wherein the liquid fraction comprising glycol is at least partially from the polymerization system.

20. The glycol purification system of any one of claims 17-19, wherein the glycol is monoethylene glycol.

21. A system comprising:(a) an ester exchanger unit configured to carry out a transesterification reaction of a recycled terephthalate content and a recycled glycol content to form one or more byproducts, wherein the one or more byproducts comprise a glycol byproduct and a PET oligomer byproduct;(b) one or more melt phase polycondensation units configured to produce one or more vapor streams, wherein the one or more vapor streams comprises a glycol vapor content and a PET oligomer vapor content; and(c) a glycol recovery unit configured to receive a glycol mixture collected and condensed from the one or more vapor streams.

22. A glycol recovery system comprising:(a) one or more glycol collection tanks configured to collect a mixture formed from one or more vapor streams of an upstream PET polymerization system, wherein the one or more vapor streams comprises one or more byproducts, wherein the one or more byproducts comprise a glycol byproduct and a PET oligomer byproduct;(b) one or more evaporation units configured to partially vaporize the mixture to form a gaseous phase and a liquid phase;(c) one or more sludge collection units configured to store the liquid phase of the evaporation unit; and(d) one or more separation units configured to form a condensate from the gaseous phase of the evaporation unit and separate the condensate into a collection fraction and a waste fraction, wherein the collection fraction comprises glycol having a purity of at least 99 w / w%.

23. The glycol recovery system of claim 22, further comprising:(e) one or more glycol collection tanks configured to receive the collection fraction recovered from the separation unit.

24. The glycol recovery system of claim 22 or 23, wherein the glycol in the collection fraction is monoethylene glycol.

25. A glycol waste recovery system comprising:(a) one or more glycol collection tanks configured to collect a mixture formed from one or more vapor streams of an upstream PET polymerization system, , wherein the one or more vapor streams comprises one or more byproducts, wherein the one or more byproducts comprise a glycol byproduct and a PET oligomer byproduct;(b) one or more evaporation units configured to partially vaporize the mixture to form a gaseous phase and a liquid phase;(c) one or more sludge collection units configured to store the liquid phase of the evaporation unit; and one or more separation units configured to form a condensate from the gaseous phase of the evaporation unit and separate the condensate into a collection fraction and a waste fraction, wherein the collection fraction comprises glycol having a purity of at least 99 w / w%.

26. The glycol waste recovery system of claim 25, further comprising:(d) one or more glycol collection tanks configured to receive the collection fraction recovered from the separation unit.

27. The glycol waste recovery system of claim 25 or 26, further comprising:(e) a glycol purification subsystem configured to purify the waste fraction and recover monoethylene glycol.

28. A system comprising:(a) an ester exchanger unit configured to carry out a transesterification reaction of a recycled terephthalate content and a recycled glycol content to form one or more byproducts comprising a glycol byproduct and a PET oligomer byproduct; and(b) one or more melt phase polycondensation units configured to produce one or more vapor streams comprising a PET oligomer vapor content; and(c) a PET oligomer recovery unit configured to condense and collect the PET oligomer vapor content to form a PET oligomer condensate; and(d) a depolymerization subsystem configured to receive the PET oligomer condensate and depolymerize the PET oligomers to recover a terephthalate and / or a glycol, wherein the depolymerization subsystem is at most 1 kilometer downstream of the ester exchanger unit and the one or more melt phase polycondensation units.

29. An integrated process for producing recycled polyethylene terephthalate (r-PET) comprising:(a) subjecting a waste polyester feedstock comprising PET to a depolymerization process, wherein the waste polyester feedstock comprises from about 75 w / w% PET to about 99 w / w% PET, wherein the depolymerization comprises: i. admixing the waste polyester feedstock with at least one portion of a solvent, thereby forming a first reaction mixture; and ii. admixing the first reaction mixture with a depolymerization catalyst, thereby forming a second reaction mixture comprising a solid fraction and a liquid fraction;(b) performing a first purification, wherein the first purification comprises melting the solid fraction to form a DMT melt, and distilling the DMT melt to yield r-DMT;(c) performing a second purification, wherein the second purification comprises: i. neutralizing the liquid fraction with an acid to form a neutralized mixture, ii. subjecting the neutralized mixture to at least two distillations to yield a methanol distillate and a MEG distillate, wherein the methanol distillate comprises a recycled methanol (r-methanol) content and the MEG distillate comprises a recycled MEG (r-MEG) content;(d) subjecting the r-DMT content and the r-MEG content to a polymerization process, thereby forming r-PET.

30. An integrated process for producing recycled polyethylene terephthalate (r-PET) comprising:(a) subjecting a waste polyester feedstock comprising PET to a depolymerization process a in a first location, wherein the depolymerization comprises: i. admixing the waste polyester feedstock with at least one portion of a solvent, thereby forming a first reaction mixture; ii. admixing the first reaction mixture with a depolymerization catalyst, thereby forming a second reaction mixture comprising a solid fraction and a liquid fraction;(b) performing a first purification, wherein the first purification comprises melting the solid fraction to form a DMT melt, and distilling the DMT melt form a DMT distillate, wherein the DMT distillate comprises a recycled DMT (r-DMT) content;(c) performing a second purification, wherein the second purification comprises: iii. neutralizing the liquid fraction with an acid to form a neutralized mixture; iv. subjecting the neutralized mixture to at least a first distillation to yield a methanol distillate and a first bottom; v. subjecting the first bottom to one or more distillations to yield a subsequent distillate, wherein the subsequent distillate comprises a recycled MEG (r- MEG) content; and(d) subjecting the r-DMT content and the r-MEG content to a polymerization process in a second location, thereby forming the r-PET, wherein the first location has a distance of at most 1 kilometer from the second location.

31. A process for recovering MEG from a polyethylene terephthalate polymerization process, comprising:(a) collecting a mixture from one or more vapor streams of the polymerization process, wherein the polymerization process comprises an ester exchanger phase and a melt phase polycondensation phase;(b) evaporating the mixture to form a liquid phase and a gaseous phase; and(c) subjecting the liquid phase to at least one separation process to form a waste fraction and a collection fraction, thereby recovering MEG from the collection fraction.

32. A process for recovering dimethyl terephthalate (DMT) and ethylene glycol (EG) from polyethylene terephthalate (PET) oligomers comprising:(a) collecting a mixture comprising PET oligomers from one or more vapor streams of a polymerization process, wherein the polymerization process comprises an ester exchanger phase and a melt phase polycondensation phase; and(b) subjecting at least a portion of the mixture to a depolymerization process, thereby recovering DMT and MEG.

33. A process for recovering ethylene glycol comprising:(a) collecting a mixture comprising ethylene glycol from one or more vapor streams of a polymerization process, wherein the polymerization process comprises an ester exchanger phase and a melt phase polycondensation phase;(b) evaporating the mixture to form a liquid phase and a gaseous phase;(c) subjecting the liquid phase to at least one separation process to form a waste fraction and a collection fraction, wherein the collection fraction comprises MEG; and(d) subjecting the waste fraction to a purification process comprising: i. neutralizing the waste fraction with at least one portion of an acid to form a neutralized mixture; ii. adding a portion of methanol to the neutralized mixture, and subjecting the neutralized mixture to a first distillation to form a first distillate and a first bottom, thereby recovering methanol from the first distillate; iii. subjecting the first bottom to one or more subsequent distillations, thereby recovering ethylene glycol from a final distillate.

34. A process of producing a polyester, the process comprising a depolymerization process and a polymerization process; wherein the depolymerization process comprises 1) adding a first alcohol to a first composition comprising a first polyester, and 2) subjecting the first polyester and the first alcohol to conditions such that the first polyester depolymerizes to form a second composition comprising an ester derivative; and wherein the polymerization process comprises subjecting the ester derivative to conditions such that the ester derivative polymerizes to form a third composition comprising a second polyester and a second alcohol.

35. The process of claim 34, wherein the first polyester depolymerizes to form the ester derivative and a first glycol.

36. The process of claim 35, wherein the polymerization process comprises subjecting the ester derivative and a second glycol to conditions such that they polymerize.

37. The process of claim 36, wherein the first glycol and the second glycol comprise the same chemical structure.

38. The process of claim 37, wherein the first glycol and the second glycol comprise different chemical structures.

39. The process of any one of claims 34-38, wherein the first polyester and the second polyester comprise the same repeat unit.

40. The process of any one of claims 34-39, wherein the first polyester and the second polyester comprise different repeat units.

41. The process of any one of claims 34-40, wherein the first alcohol and the second alcohol comprise the same chemical structure.

42. The process of any one of claims 34-41, wherein the first alcohol and the second alcohol comprise different chemical structures.

43. The process of any one of claims 34-42, wherein the ester derivative is a terephthalate.

44. The process of any one of claims 34-43, wherein the first alcohol comprises at least a portion of the second alcohol recycled from the third composition.

45. The process of any one of claims 34-44, wherein the second glycol comprises at least a portion of the first glycol recycled from the second composition.

46. The process of any one of claims 34-45, wherein the ester derivative in the polymerization process is purified from the depolymerization process or the polymerization process.

47. The process of any one of claims 34-46, wherein the first alcohol is purified from the depolymerization process or the polymerization process.

48. The process of any one of claims 34-47, wherein the second alcohol is purified from the depolymerization process or the polymerization process.

49. The process of any one of claims 36-48, wherein the first glycol is purified from the depolymerization process or the polymerization process.

50. The process of any one of claims 36-49, wherein the second glycol is purified from the depolymerization process or the polymerization process.

51. The process of any one of claims 34-50, wherein the depolymerization process and the polymerization process are performed within about 10 meters, about 20 meters, about 30 meters, about 40 meters, about 50 meters, about 60 meters, about 70 meters, about 80 meters, about 90 meters, about 100 meters, about 200 meters, about 300 meters, about 400 meters, about 500 meters, about 1,000 meters, about 2,000 meters, about 3,000 meters, about 4,000 meters, about 5,000 meters, about 6,000 meters, about 7,000 meters, about 8,000 meters, about 9,000 meters, or about 10,000 meters.

52. The process of any one of claims 34-51, wherein the depolymerization process is adjacent to an alcohol purification process.

53. The process of any one of claims 34-52, wherein the depolymerization process is adjacent to a terephthalate purification process.

54. The process of any one of claims 34-53, wherein the depolymerization process and the polymerization process are fluidically coupled.

55. The process of any one of claims 34-54, wherein the first composition comprises recycled polyester material or non -recycled polyester material.

56. The process of any one of claims 34-55, wherein the first composition comprises postconsumer PET.

57. The process of any one of claims 34-56, wherein the first composition comprises an impurity.

58. The process of any one of claims 34-57, wherein the first composition comprises at least about 50 wt%, at least about 55 wt%, at least about 60 wt%, at least about 65 wt%, at least about 70 wt%, at least about 75 wt%, at least about 80 wt%, at least about 85 wt%, at least about 90 wt%, at least about 95 wt%, at least about 96 wt%, at least about 97 wt%, at least about 98 wt%, at least about 99 wt%, at least about 99.1 wt%, at least about 99.2 wt%, at least about 99.3 wt%, at least about 99.4 wt%, at least about 99.5 wt%, at least about 99.6 wt%, at least about 99.7 wt%, at least about 99.8 wt%, or at least about 99.9 wt% of the first polyester.

59. The process of any one of claims 34-58, wherein the first composition comprises at most about 50 wt%, at most about 55 wt%, at most about 60 wt%, at most about 65 wt%, at most about 70 wt%, at most about 75 wt%, at most about 80 wt%, at most about 85 wt%, at most about 90 wt%, at most about 95 wt%, at most about 96 wt%, at most about 97 wt%, at most about 98 wt%, at most about 99 wt%, at most about 99.1 wt%, at most about 99.2 wt%, at most about 99.3 wt%, at most about 99.4 wt%, at most about 99.5 wt%, at most about 99.6 wt%, at most about 99.7 wt%, at most about 99.8 wt%, or at most about 99.9 wt% of the first polyester.

60. The process of any one of claims 34-59, wherein the first composition comprises polyester flakes, polyester fines, polyester purge fines, polyester fibers, densified polyester fibers, or any combination thereof.

61. The process of any one of claims 34-60, wherein the first composition comprises polyesters comprising mixed colors.

62. The process of any one of claims 34-61, wherein the first composition comprises at least one of: polyethylene, polypropylene, polyvinylidene chloride, ethylene-vinyl acetate, ethylene-vinyl alcohol copolymer, an elastomer, paper-based material, ethylene propylenediene monomer (EPDM) rubber, nylon, chlorosulfonated polyethylene, polyamide, aramid, polyvinylchloride-polyvinyl acrylic acid copolymer, polystyrene, styrene butyl methacrylate copolymer, silicone rubber, wood, polyacrylate, polydimethylsiloxane, rubber, neprone, chlorobutyl polycorp, polytetrafluoroethylene, fiberglass, styrene butadiene rubber, or any combination thereof.

63. The process of claim 62, wherein the paper-based material comprises packaging material.

64. The process of claim 63, wherein the packaging material comprises cardboard.

65. The process of any one of claims 34-64, wherein the first alcohol is continuously added to the depolymerization process.

66. The process of any one of claims 35-65, wherein the first glycol is continuously added to the polymerization process.

67. The process of any one of claims 36-64, wherein the depolymerization process further comprises adding alcohol not from the depolymerization process or the polymerization process to the first composition.

68. The process of claim 67, wherein the depolymerization process further comprises adding the alcohol not from the depolymerization process or the polymerization process to the first composition before or after the recycled alcohol is added to the first composition.

69. The process of any one of claims 36-68, wherein the polymerization process further comprises adding glycol not from the depolymerization process or the polymerization process to the ester derivative.

70. The process of claim 69, wherein the depolymerization process further comprises adding the alcohol not from the depolymerization process or the polymerization process to the ester derivative before or after the recycled glycol is added to the terephthalate.

71. The process of any one of claims 34-70, wherein the first polyester, the second polyester, or both comprises: polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene sebacate), poly(ethylene adipate), poly(ethylene isophthalate), poly(ethylene phthalate), poly(butylene sebacate), poly(butylene succinate), poly(hexylene sebacate), polyhydroxybutyrate, polyethylene naphthalate, polyglycolide, polyglycolide, polyglycolic acid, polylactic acid, polycaprolactone, poly(Bisphenol A isophthalate), poly(Bisphenol A terephthalate), poly(ethylene glycol-co-l,4-cyclohexanedimethanol terephthalate), poly(3- hydroxybutyrate-co-3 -hydroxy valerate), polyester of 4-hydroxybenzoic acid and 6- hydroxynaphthalene-2-carboxylic acid, Vectran®, cutin, or any combinations thereof.

72. The process of any one of claims 34-71, wherein the first alcohol, the second alcohol, or both comprises: methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-l,4-diyldimethanol, phenol, benzyl alcohol methanol, or any combination thereof.

73. The process of any one of claims 34-72, wherein the first glycol, the second glycol, or both comprises: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3- butanediol, 2,3 -butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5- pentanediol, 2,3 -pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3 -hexanediol, 1,4- hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,3 -hexanediol, 2,4-hexanediol, 2,5-hexanediol, 3,4-hexanediol, Bisphenol A, or any combination thereof.

74. The process of any one of claims 34-73, wherein the depolymerization process uses a first catalyst.

75. The process of claim 74, wherein the first catalyst comprises an alkoxide.

76. The process of claim 75, wherein the alkoxide comprises: methoxide, ethoxide, n- propoxide, n-butoxide, t-butoxide, sec-butoxide, iso-butoxide, iso-propoxide, or any combination thereof.

77. The process of claim 75 or 76, wherein the alkoxide comprises a metal alkoxide.

78. The process of claim 77, wherein the metal alkoxide comprises a cation selected from the group consisting of: lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, ammonium, and any combination thereof.

79. The process of any one of claims 74-78, wherein the first catalyst comprises a glycoxide.

80. The process of claim 79, wherein the glycoxide comprises a metal glycoxide.

81. The process of claim 80, wherein the metal glycoxide comprises a cation selected from the group consisting of: lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, ammonium, and any combination thereof.

82. The process of any one of claims 34-81, wherein the polymerization process uses a second catalyst.

83. The process of claim 82, wherein the second catalyst comprises an antimony compound or a titanium compound.

84. A separation process, comprising:(a) providing a mixture comprising (i) a mono-alcohol, (ii) a diol, and (iii) an alkoxide;(b) adding an acid to the mixture; and(c) distilling the mixture to produce (i) a distillate comprising an increased ratio of the mono-alcohol to the diol compared to the mixture and (ii) a bottom comprising an increased ratio of the diol to the mono-alcohol compared to the mixture.

85. The process of claim 84, wherein the acid comprises: sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, phosphorous acid, carbonic acid, acetic acid, perchloric acid, chloric acid, chlorous acid, hypochlorous acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, or any combinations thereof.

86. The process of claim 84 or 85, further comprising recycling the distillate for use in a polyester depolymerization process.

87. The process of any one of claims 84-86, further comprising recycling the bottom for use in a polyester polymerization process.

88. The process of any one of claims 84-87, wherein the distilling comprises:(a) distilling the mixture using a first distillation column to produce the distillate and a first intermediate composition;(b) distilling the first intermediate composition using a second distillation column to produce a second intermediate composition and a waste bottom; and(c) distilling the second intermediate composition using a third distillation column to produce a waste distillate and the bottom.

89. The process of claim 88, wherein the distillation columns are thermally integrated.

90. A separation process, comprising:(a) heating a mixture comprising (i) a terephthalate in a solid phase and (ii) an alcohol to dissolve the terephthalate;(b) flash evaporating a part of the mixture to evaporate the alcohol from the mixture; and(c) distilling the mixture to produce a distillate, wherein the distillate comprises a higher fraction of the terephthalate than the mixture.

91. The process of claim 90, further comprising producing terephthalate flakes from the distillate, and optionally, further comprising using the terephthalate flakes in a polymerization process to produce a polyester.

92. A method of producing polyester, the method comprising a depolymerization process and a polymerization process;(a) wherein the depolymerization process comprises 1) adding a first alcohol to a first composition comprising a first polyester, and 2) subjecting the first polyester and thefirst alcohol to conditions such that the first polyester depolymerizes to form a second composition comprising a terephthalate and a glycol;(b) wherein the polymerization process comprises subjecting the terephthalate and the glycol in the second composition to conditions such that they polymerize to form a third composition comprising a second polyester and a second alcohol;(c) wherein the first alcohol comprises at least a portion of the second alcohol recycled from the third composition.

93. The method of claim 92, wherein the first alcohol comprises at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% recycled second alcohol.

94. The method of claim 92, wherein the first alcohol comprises at least 90% recycled second alcohol.

95. The method of claim 92, wherein the first alcohol comprises at least 95% recycled second alcohol.

96. The method of claim 92, wherein the depolymerization process and the polymerization process are fluidically coupled to each other.

97. The method of claim 92, wherein the polymerization process is performed within 1000 meters from the depolymerization process.

98. The method of claim 92, wherein the terephthalate in the second composition is used in the polymerization process within 1 hour after the terephthalate is formed in the depolymerization process.

99. The method of claim 92, wherein the third composition comprises residual glycol not reacted in the polymerization process, and the method further comprises separating residual glycol and adding it to the polymerization process.

100. The method of claim 92, wherein the second composition comprises residual first alcohol not reacted in the depolymerization process, and the method further comprises separating the residual first alcohol and adding it to the depolymerization process.

101. The method of claim 92, wherein the first alcohol is at least one of methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane- 1,4- diyldimethanol, phenol, benzyl alcohol methanol, or any combination thereof.

102. The method of claim 92, wherein the terephthalate is dimethyl terephthalate.

103. The method of claim 92, wherein the glycol is ethylene glycol.

104. The method of claim 92, wherein the second polyester is the same type of polyester as the first polyester.

105. The method of claim 92, wherein the second polyester is a different type of polyester from the first polyester.

106. The method of claim 92, wherein at least the first or the second polyester is polyethylene terephthalate (PET).

107. The method of claim 92, wherein the first polyester comprises post-consumer PET.

108. The method of claim 92, subsequent to the depolymerization process, further comprises a separation process, wherein at least one of the terephthalate and the glycol are separated from the second composition.

109. The method of claim 108, wherein the separation process comprises removing a solid from the second composition.

110. The method of claim 109, wherein the separation process uses a screener to remove the solid from the second composition.

111. The method of claim 110, wherein the screener has pore size smaller than 1 mm.

112. The method of claim 109, wherein the solid comprises remaining first polyester unreacted in the depolymerization process.

113. The method of any one of claims 109-112, wherein the separation process further comprises using filtration module to separate the terephthalate from the glycol in the second composition.

114. The method of claim 92, wherein the second composition comprises residual first alcohol not reacted in the depolymerization process, and the separation process further comprises separating the residual first alcohol from the terephthalate.

115. The method of claim 108, wherein the separation process is performed at a pressure about 1 atm.

116. The method of claim 108, wherein the separated terephthalate is in a crystalline state.

117. The method of claim 108, wherein the separated glycol is in a liquid state.

118. The method of claim 92, further comprising purifying the terephthalate subsequent to the depolymerization process and before the polymerization process.

119. The method of claim 92, wherein the second alcohol is continuously added to the depolymerization process.

120. The method of claim 92, wherein the glycol recycled from the depolymerization process is continuously added to the polymerization process.

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