FIELD OF THE INVENTION

The present disclosure relates to processes for recovering polyesters from feedstocks.

BACKGROUND OF THE INVENTION

Certain conventional systems may recycle polyesters. However, certain feedstocks for recycling polyesters are mixed component feedstocks. The mixed component nature of such feedstocks can result in low recycling yields and/or resource intensive processes.

BRIEF SUMARY OF THE INVENTION

In one aspect, a process for recovering one or more polyesters from a feedstock composition is provided. The process can include exposing a feedstock composition to a solvent, wherein the feedstock composition comprises one or more polyesters and one or more non-polyester components. The solvent can be selected from the group consisting of 4-methylcyclohexanemethanol (MCHM), ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4-cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2-methyl-2,4-pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), or a combination thereof. The exposing occurs at a temperature of from 150 °C to 300 °C to dissolve at least a portion of the one or more polyesters from the feedstock composition in the solvent, thereby forming a polyester liquid component. The process can also include separating at least a portion of the one or more non-polyester components from the polyester liquid component, wherein the separating occurs at a temperature of from 150 °C to 300 °C. The process can also include cooling the polyester liquid component to a temperature below 50 °C; and recovering the at least a portion of the one or more polyesters from the polyester liquid component by a solid-liquid separation.

In another aspect, a process for recovering one or more polyesters from a feedstock composition is provided. The process can include exposing a feedstock composition to a first solvent, the first solvent comprising dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), tetrahydrofuran (THF), ethanol, 2-ethyl hexanol (2-EH), 4-methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, wherein the feedstock composition comprises one or more polyesters and one or more non-polyester components. The exposing can occur at a temperature of from 70 °C to 200 °C to dissolve at least a first portion of the non-polyester components. The process can also include separating at least the first portion of the non-polyester components from the one or more polyesters, wherein the separating occurs at a temperature of from 70 °C to 200 °C. The process can also include exposing the one or more polyesters to a second solvent, the second solvent comprising 4- methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, to dissolve at least a portion of the one or more polyesters thereby forming a polyester liquid component. The exposing can occur at a temperature of from 150 °C to 300 °C. The process can also include recovering the at least a portion of the one or more polyesters from the polyester liquid component by a solid-liquid separation.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an example system for recovering polyesters from a feedstock composition and optionally depolymerizing at least a portion of the recovered polyester, in accordance with aspects of the present disclosure.

FIG. 2 is another example system for recovering polyesters from a feedstock composition and optionally depolymerizing at least a portion of the recovered polyester, in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Overview

The present disclosure may be understood more readily by reference to the following detailed description of certain aspects of the disclosure and working examples. In according with the purpose(s) of this disclosure, certain aspects of the disclosure are described in the Brief Summary of the Invention and are further described herein below. Also, other aspects of the disclosure are described herein.

Aspects herein are directed to processes for recovering polyesters from feedstock compositions. As described herein, an example process can include exposing a feedstock composition to one or more solvents to dissolve at least a portion of the polyester and/or the non-polyester components, in an aspect. In various aspects, the processes can also include one or more solid-liquid separations to recover the polyester and/or to remove the non-polyester components. In certain aspects, as discussed below, the feedstock can be exposed to different solvents and/or different temperatures in series to recover the polyesters.

As discussed above, certain conventional systems may recycle polyesters; however certain feedstocks for such processes may be mixed-component feedstocks. The mixed component nature of such feedstocks can result in low recycling yields and/or resource intensive processes.

The processes and systems disclosed herein can alleviate one or more of the above problems. For instance, in certain aspects, the processes disclosed herein can include exposing a feedstock composition to one or more solvents to dissolve at least a portion of the polyester and/or the non-polyester components, in an aspect. In various aspects, the processes can also include one or more solid-liquid separations to recover the polyester and/or to remove the non-polyester components. In certain aspects, as discussed below, the feedstock can be exposed to different solvents and/or different temperatures in series to recover the polyesters. In aspects, the recovered polyesters can provide a more refined feed source for one or more depolymerization processes, which can provide for a less resource intensive depolymerization process, e.g., since at least a portion of the non-polyester components have been removed.

Feedstock Compositions

As discussed above, the processes described herein relate to recovering polyesters from feedstock compositions. The feedstock compositions can include one or more polyester components and one or more non-polyester components. The term “polyester” can refer to a synthetic polymer prepared by the reaction of one or more difunctional carboxylic acids and/or multifunctional carboxylic acids with one or more difunctional hydroxyl compounds and/or multifunctional hydroxyl compounds. The difunctional carboxylic acid can be a dicarboxylic acid and the difunctional hydroxyl compound can be a dihydric alcohol such as, for example, glycols. Furthermore, as used herein, the term “diacid” or “dicarboxylic acid” includes multifunctional acids, such as branching agents. The term “glycol” or “diol” as used herein, includes, but is not limited to, diols, glycols, and/or multifunctional hydroxyl compounds. The dicarboxylic acid residues may be derived from a dicarboxylic acid monomer or its associated acid halides, esters, salts, anhydrides, or mixtures thereof. As used herein, therefore, the term dicarboxylic acid is intended to include dicarboxylic acids and any derivative of a dicarboxylic acid, including its associated acid halides, esters, halfesters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof, useful in a reaction process with a diol to make polyester. It should be understood that the term “polyester” as used herein also refers to copolyesters.

As used herein, the term “residue(s)” refers to the monomer unit or repeating unit in a polymer, oligomer, or dimer. For example, a polymer can be made from the condensation of the following monomers: terephthalic acid (“TPA”) and cyclohexyl-1 ,4-dimethanol (“CHDM”). The condensation reaction results in the loss of water molecules. The residues in the resulting polymer are derived from either terephthalic acid or cyclohexyl-1 , 4-dimethanoL Below in Formula (I), a non-limiting example of a polyester is provided.

In aspects, one or more of the polyesters exhibit an inherent viscosity of from about 0.1 dL/g to about 1.2 dL/g as determined according to ASTM D2857-70, about 0.2 dL/g to about 1.2 dL/g as determined according to ASTM D2857-70, about 0.3 dL/g to about 1 .2 dL/g as determined according to ASTM D2857-70, or about 0.4 dL/g to about 1 .2 dL/g as determined according to ASTM D2857-70.

In various aspects, the one or more polyesters can include terephthalate polyesters. Terephthalate polyesters are polyesters that comprise residues of terephthalic acid or residues of any derivative of terephthalic acid, including its associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, and/or mixtures thereof or residues thereof useful in a reaction process with a diol to make a copolyester In various aspects, the polyester composition can include polyethylene terephthalate (PET). In one or more aspects, the polyester composition can include glycol-modified PET. In certain aspects, the polyester composition can include polyethylene terephthalate (PET), 1 ,4- cyclohexanedimethanol (CHDM)-modified PET, isophthalic acid (IPA)-modified PET, diethylene glycol (DEG)-modified PET, glycol-modified PET, neopentyl glycol (NPG)- modified PET, propane diol (PDO)-modified PET, butanediol (BDO)-modified PET, heaxanediol (HDO)-modified PET, 2-methyl-2,4-pentanediol (MP diol)-modified PET, isosorbide-modified PET, polycyclohexylenedimethylene terephthalate (PCT), cyclohexanedimethanol (CHDM)-containing copolyester, isosorbide-containing copolyester, or a combination thereof.

In various aspects, the polyester composition can include CHDM. In one aspect, the polyester composition can include about 0 mole % to about 100 mole % CHDM, about 1 mole % to about 100 mole % CHDM, about 1 mole % to about 90 mole % CHDM, about 1 mole % to about 80 mole % CHDM, about 1 mole % to about 70 % CHDM, about 1 mole % to about 60 mole % CHDM, about 1 mole % to about 50 mole % CHDM, about 1 mole % to about 40 mole % CHDM, about 1 mole % to about 35 mole % CHDM, about 1 mole % to about 30 mole % CHDM, about 1 mole % to about 25 mole % CHDM, about 1 mole % to about 20 mole % CHDM, about 1 mole % to about 10 mole % CHDM, or about 1 mole % to about 5 mole % CHDM. In aspects, the mole % of CHDM refers to the mole % of CHDM relative to all diol equivalents in the polyester composition. In various aspects, the polyester composition can include DEG. In aspects, the polyester composition can include about 0 mole % to about 100 mole % DEG, about 1 mole % to about 100 mole % DEG, about 1 mole % to about 90 mole % DEG, about 1 mole % to about 80 mole % DEG, about 1 mole % to about 70 mole % DEG, about 1 mole % to about 60 mole % DEG, about 1 mole % to about 50 mole % DEG, about 1 mole % to about 40 mole % DEG, about 1 mole % to about 35 mole % DEG, about 1 mole % to about 30 mole % DEG, about 1 mole % to about 20 mole % DEG, about 1 mole % to about 10 mole % DEG, about 1 mole % to about 5 mole % DEG, or about 1 mole % to about 3 mole % DEG. In aspects, the mole % of DEG refers to the mole % of DEG relative to all diol equivalents in the polyester composition. In aspects, the polyester composition can include isophthalic acid. In aspects, the polyester composition can include about 0 mole % to about 30 mole % isophthalic acid, about 1 mole % to about 30 mole % isophthalic acid, about 1 mole % to about 25 mole % isophthalic acid, about 1 mole % to about 20 mole % isophthalic acid, about 1 mole % to about 15 mole % isophthalic acid, about 1 mole % to about 10 mole % isophthalic acid, about 1 mole % to about 7.5 mole % isophthalic acid, about 1 mole % to about 5 mole % isophthalic acid, about 1 mole % to about 3 mole % isophthalic acid, about 10 mole % or less of isophthalic acid, about 7.5 mole % or less of isophthalic acid, about 5 mole % or less of isophthalic acid, or about 3 mole % or less of isophthalic acid. In aspects, the mole % of isophthalic acid refers to the mole % of isophthalic acid relative to all diacid equivalents in the polyester composition In certain aspects, the polyester composition can include about 0 mole % to about 100 mole % CHDM, about 0 mole % to about 100 mole % DEG, about 0 mole % to about 30 mole % isophthalic acid, or a combination thereof. In certain aspects, the polyester composition can include about 1 mole % to about 100 mole % CHDM, about 1 mole % to about 100 mole % DEG, about 1 mole % to about 30 mole % isophthalic acid, or a combination thereof. In various aspects, the polyester composition can include other glycols, e.g., other than those mentioned above. For instance, in aspects, the polyester composition can include, but is not limited to, neopentyl glycol (NPG), 2-methyl-2,4- pentanediol (MP diol), butanediol (BDO), propanediol (PDO), hexanediol (HDO), isosorbide, poly(tetramethylene ether) glycol (PTMG), poly(ethylene) glycol (PEG), or a combination thereof. In certain aspects, each of the NPG, MP diol, BDO, PDO, HDO, isosorbide, PTMG, and PEG can be present in the polyester composition in an amount of 0 mole % to about 100 mole %, about 1 mole % to about 100 mole %, about 1 mole

% to about 90 mole %, about 1 mole % to about 80 mole %, about 1 mole % to about 70 %, about 1 mole % to about 60 mole %, about 1 mole % to about 50 mole %, about 1 mole % to about 40 mole %, about 1 mole % to about 35 mole %, about 1 mole % to about 30 mole %, about 1 mole % to about 25 mole %, about 1 mole % to about 20 mole %, about 1 mole % to about 10 mole %, or about 1 mole % to about 5 mole %. In aspects, the mole % of each of NPG, MP diol, BDO, PDO, HDO, isosorbide, PTMG, and PEG refers to the mole % of each of NPG, MP diol, BDO, PDO, HDO, isosorbide, PTMG, and PEG, respectively, relative to all diol equivalents in the polyester composition. In various aspects, the polyester composition can include CHDM, DEG, NPG, MP diol, BDO, PDO, HDO, isosorbide, PTMG, PEG, isophthalic acid, or a combination thereof, where each component is present in any of the amounts for such components described in this paragraph.

In certain aspects, the polyester component can be present in the feedstock composition in any amount. In various aspects, the polyester component can be present in the feedstock composition in an amount of from 10 wt. % to 99 wt. %, 10 wt. % to 95 wt. %, 10 wt. % to 90 wt. %, 10 wt. % to 85 wt. %, 10 wt. % to 75 wt. %, 10 wt. % to 65 wt. %, 10 wt. % to 55 wt. %, 10 wt. % to 50 wt. %, relative to the total weight of the feedstock composition.

In various aspects, as discussed above, the feedstock composition can include one or more non-polyester components. In various aspects, the non-polyester components may include, but are not limited to, polyvinyl chloride (PVC), polyvinyl acetal, polyvinyl butyral (PVB), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), cotton, polyolefins, polyethylene, polypropylene, polystyrene, polycarbonate, Spandex, natural fibers, cellulose ester, polyacrylates, polymethacrylate, polyamides, nylon, poly(lactic acid), polydimethylsiloxane, polysilane, calcium carbonate, titanium dioxide, inorganic fillers, dyes, pigments, color toners, colorants, plasticizers, adhesives, flame retardants, metals, aluminum, and iron, or a combination thereof. In certain aspects, the non-polyester component can include cotton, polycarbonate, Spandex, natural fibers, cellulose ester, polyacrylates, polymethacrylate, polyamides, nylon, poly(lactic acid), polydimethylsiloxane, polysilane, calcium carbonate, titanium dioxide, inorganic fillers, dyes, pigments, color toners, colorants, plasticizers, adhesives, flame retardants, metals, aluminum, iron, or a combination thereof. In various aspects, the non-polyester component can include polyolefins, polyethylene, polypropylene, polystyrene, polyvinyl chloride (PVC), polyvinyl acetal, polyvinyl butyral (PVB), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), or a combination thereof. . In various aspects, the non-polyester component can include polyolefins, polyethylene, polypropylene, polystyrene, polyvinyl chloride (PVC), polyvinyl acetal, polyvinyl butyral (PVB), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), nylon, or a combination thereof. In certain aspects, the non-polyester component can include polyolefins, polyethylene, polypropylene, polystyrene, or a combination thereof.

In certain aspects, the non-polyester component can be present in the feedstock composition in any amount. In various aspects, the non-polyester components can be present in the feedstock composition in an amount of from about 0.01 wt. % to about 50 wt. %, about 0.01 wt. % to about 40 wt. %, about 0.01 wt. % to about 30 wt. %, about 0.01 wt. % to about 20 wt. %, about 0.01 wt. % to about 15 wt. %, about 0.01 wt. % to about 10 wt. %, about 0.01 wt. % to about 7.5 wt. %, about 0.01 wt. % to about 5 wt. %, about 0.01 wt. % to about 2.5 wt. %, about 0.01 wt. % to about 1 .0 wt. %, relative to the weight of the one or more polyesters in the feedstock composition.

In aspects, the feedstock composition can include recycled polyesters. In various aspects, the recycled polyester(s) can include material that was recovered as manufacturing scrap, industrial waste, post-consumer waste, or a combination thereof. In aspects, the recycled polyester(s) can be prior-used products that have been used and/or discarded. In aspects, the feedstock composition and/or recycled polyester(s) can come from various sources and/or in various forms, including but not limited to textiles, carpet, thermoformed materials, bottles, pellets, and film.

Recovering Polyesters from the Feedstock Compositions

As discussed above, the processes disclosed herein can include exposing a feedstock composition to one or more solvents to dissolve at least a portion of the polyester or the non-polyester components, in an aspect. Further, in certain aspects, solid-liquid separations may be utilized to recover the polyester and/or remove at least a portion of the non-polyester component. In various aspects, the specific solvents used and/or the temperatures at which the feedstock are exposed to such solvents may determine what component is solubilized and what component is in an insoluble portion, thereby allowing for separation.

In certain aspects, the solvents can include 4- methylcyclohexanemethanol (MCHM), ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4-cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2-methyl-2,4- pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), tetrahydrofuran (THF), ethanol, 2-ethyl hexanol (2-EH), 4- methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof. In certain aspects, the solvents can include 4-methylcyclohexanemethanol (MCHM), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), or a combination thereof, and optionally ethylene glycol (EG). In one or more aspects, the solvents can include dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), tetrahydrofuran (THF), ethanol, 2-ethyl hexanol (2-EH), 4- methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof. In various aspects, the solvents can include 4-methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof.

In various aspects, the weight ratio of the feedstock to the solvent can be of from 1 :100, 1 :90, 1 :80, 1 :70, 1 :60, 1 :50, 1 :40, 1 :30, 1 :20, 1 :10, 1 :5, 1 :3, 1 :2, 2:3, 1 :1 , or 3:2. In the same or alternative aspects, when exposing the feedstock composition to the solvent, the feedstock composition can be present in an amount of 1 wt. % or more, 2 wt. % or more, 5 wt.% or more, 7 wt. % or more, 10 wt. % or more, 15 wt. % or more, 20 wt. % or more, 25 wt. % or more, 30 wt. % or more, 40 wt. % or more, or 50 wt. % or more, relative to the weight of the solvent. In various aspects, when exposing the feedstock composition to the solvent, the feedstock composition can be present in a range of about 0.1 wt. % to 60 wt. %, 0.1 wt. % to 50 wt. %, 0.1 wt. % to 40 wt. %, 0.1 wt. % to 30 wt. %, 0.1 wt. % to 25 wt. %, or 0.1 wt. % to 20 wt. %. In various aspects, the solvents and/or temperature range at which the feedstock is exposed can allow for various components to dissolve while other remain insoluble. For instance, in various aspects, 4-methylcyclohexanemethanol (MCHM), ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4- cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2-methyl-2,4-pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), or a combination thereof may be utilized to dissolve one or more polyesters while other components in the feedstock may remain insoluble. In such aspects, 4- methylcyclohexanemethanol (MCHM), ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4-cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2-methyl-2,4- pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), or a combination thereof, and when exposed to a feedstock at a temperature range of 150 °C to 300 °C may be utilized to dissolve one or more polyesters while other components in the feedstock may remain insoluble, such as, cotton, polycarbonate, Spandex, natural fibers, cellulose ester, polyacrylates, polymethacrylate, polyamides, nylon, poly(lactic acid), polydimethylsiloxane, polysilane, calcium carbonate, titanium dioxide, inorganic fillers, dyes, pigments, color toners, colorants, plasticizers, adhesives, flame retardants, metals, aluminum, and/or iron.

In certain aspects, the solvents dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), tetrahydrofuran (THF), ethanol, 2-ethyl hexanol (2-EH), 4- methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, may dissolve one or more non-polyester components and/or may cause one or more of the non-polyester components to melt, while the polyester component remains insoluble. In such aspects, at a temperature in a range from 70 °C to 250 °C, or 70 °C to 200 °C, or at about 95 °C, the solvents dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), tetrahydrofuran (THF), ethanol, 2-ethyl hexanol (2-EH), 4- methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, may dissolve one or more non-polyester components and/or may cause one or more of the non-polyester components to melt, while the polyester component remains insoluble. In such aspects, the melted polyester components can include polyolefins, polyethylene, polypropylene, polystyrene, or a combination thereof. In various aspects, the melted, gel-like, component may form a layer, e.g., on top of the solvent, thereby allowing for easy separation from the solvent and/or from the insoluble components. In the same or alternative aspects, the dissolved non-polyester components may include PVC, polyvinyl acetal, polyvinyl butyral (PVB), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), or a combination thereof.

In various aspects, the solvents 4-methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, may dissolve one or more polyester components, while leaving certain non-polyester components insoluble. For instance, the solvents 4-methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, at a temperature of 150 °C to 300 °C, may dissolve one or more polyester components while one or more non-polyester components may remain insoluble, such as for example, nylon or cotton.

As discussed above, the selective dissolution of one or more polyester components and/or non-polyester components in one or more solvents may allow for separation of a component. For instance, in certain aspects, once a portion of the feedstock is dissolved such a portion may be separated from an insoluble portion using any suitable solid-liquid separation techniques. A non-limiting list of example solidliquid separation techniques includes solid-liquid separation comprises filtration, centrifugation, settling, and sedimentation. In various aspects, one, or more than one, solid-liquid separation technique may be utilized. In certain aspects, one or more of the non-polyester components may not dissolve and may not remain fully insoluble in the presence of one or more solvents at a given temperature. For instance, in certain aspects, one or more of the non-polyester components may melt and float and/or form a distinct layer in the solvent. In such aspects, the melted component can also be removed by any suitable separation process, e.g., via a pump or other process.

In various aspects, the separation of the polyester component from at least a portion of the non-polyester components in the feedstock, does not result in substantial depolymerization of the polyester. In certain aspects, once the polyester component is at least partly separated from a portion of the non-polyester components in the feedstock composition, the polyester component exhibits a weight average molecular weight (Mw) that is at least 50 %, at least 60 %, or at least 75 % of the weight average molecular weight of the one or more polyesters in the feedstock composition. In the same or alternative aspects, once the polyester component is at least partly separated from a portion of the non-polyester components in the feedstock composition, the separated polyester component exhibits a degree of polymerization (DP) of 10 or more, 1 1 or more 12 or more, or 15 or more. Degree of polymerization with respect to a polyester, e.g., PET, is described in detail below.

As discussed above, in various aspects, a series of solvents followed by solid-liquid separations can result in the separation of polyesters from several components having varying solubility in various solvents. For instance, in such aspects, a first solvent can be utilized which may selectively dissolve a first portion of non-polyester components and/or may cause a second portion of the non-polyester components to melt and form a layer on the solvent, while the polyester component remains insoluble. In such an aspect, the polyester component can be separated from the dissolved first portion of non-polyester components and/or from the melted layer of the second portion of the non-polyester components. In such aspects, the polyester component and remaining insoluble components can then be exposed to another solvent (and/or another temperature) where the polyester component dissolves and a third portion of the non-polyester component remains insoluble, thereby allowing for separation of the polyester component from the third portion of non-polyester components. Example aspects of certain solvents, temperatures, and the behavior of certain polyester components and non-polyester components is discussed above in detail and can be utilized to inform the formation of multiple types of series of various solvents, temperatures, and solid-liquid separations to arrive at a desired polyester separation process depending upon the composition of the feedstock. Depolymerization Processes

As discussed above, in various aspects the polyester recovered from the feedstock composition can be exposed to a depolymerization process to recover one or more dialkyl terephthalates, ethylene glycol, or both. In various aspects, any suitable depolymerization process can be utilized. In certain aspects, the depolymerization process can include an initial depolymerization step, an alcoholysis step, or both. As one example, below, an initial depolymerization step followed by an alcoholysis step is described.

Glycolysis and/or Depolymerization of the Polyester Composition

As discussed above, in various aspects, the processes disclosed herein can include exposing one or more polyesters or a polyester composition to depolymerization conditions to depolymerize at least a portion of the one or more polyesters or polyester composition into one or more depolymerization products. In describing depolymerization processes, including the glycolysis and alcoholysis processes, the term polyester composition and the phrase one or more polyesters may be used interchangeably. In various aspects, the one or more depolymerization products can include monomers, oligomers, or a combination thereof. In certain aspects, the oligomers can exhibit a degree of polymerization from 2 to 10, 2 to 8, 2 to 6, or 2 to 4. In aspects, the one or more polyesters may be depolymerized into one or more depolymerization products that can include monomers and terephthalate oligomers having a degree of polymerization from 2 to 10, 2 to 8, 2 to 6, or 2 to 4. In aspects, liquid chromatography can be utilized to discern the degree of polymerization of an oligomer, and/or gel permeation chromatography can be utilized to discern the molecular weight of the oligomers.

In aspects, the term degree of polymerization (DP) can refer to the number of residues in the oligomer. As used herein, the degree of polymerization (DP) refers to the number of difunctional carboxylic acid residues and/or multifunctional carboxylic acid residues in the oligomer. For instance, in one example aspect, a DP of one, would refer to a residue that includes one terephthalic acid residue or one isophthalic acid residue. In such an example aspect, a DP of one can also be referred to as a monomer. A non-limiting example of a DP of one is provided below in formula (II).

[0028] Formulas (III) - (V) below show non-limiting examples of oligomers having a DP of two, three, and n, respectively, in aspects. In aspects, this depolymerization can occur via a glycolysis process. Generally, in aspects, the glycolysis process disclosed herein can include exposing one or more polyesters to one or more glycols, where the glycols react with the polyester, optionally in the presence of a trans-esterification catalyst, forming a mixture of bis(hydroxyethyl) terephthalate (BHET) or other terephthalate residue depending upon the glycol used (e.g., bis(2-hydroxydiethylene terephthalate) (BHDET) when DEG is utilized) and low molecular weight terephthalate oligomers. Some representative examples of glycolysis methods are disclosed in U.S. Pat. Nos. 3,257,335; 3,907,868; 6,706,843; and 7,462,649, and are incorporated by reference herein.

In one aspect of a glycolysis process, one or more polyesters, e.g., one or more recycled polyesters, and one or more glycols can be fed into a glycolysis reactor where the one or more recycled polyesters are dissolved and depolymerized under depolymerization conditions.

In aspects, any amount of the one or more glycols suitable for use in a glycolysis process can be utilized. In various aspects, the weight ratio of the one or more glycols relative to the amount of the polyester composition can be of from 9:1 to 1 :9, 8:1 to 1 :9, 7:1 to 1 :9, 6:1 to 1 :9, 5:1 to 1 :9, 4:1 to 1 :9, 3:1 to 1 :9, 2:9 to 1 :9, 9:1 to 1 :8, 9:1 to 1 :7, 9:1 to 1 :6, 9:1 to 1 :5, 9:1 to 1 :4, 9:1 to 1 :3, or 9:1 to 1 :2.

In certain aspects, the one or more glycols can include any glycol suitable for use in a glycolysis process. As used herein, the term “glycol” refers to aliphatic, alicyclic, and aralkyl glycols. Exemplary glycols include ethylene glycol, 1 ,2- propandiol (also known propylene glycol), 1 ,3-propanediol, 1 ,4-butanediol, 1 ,5- pentanediol, 1 ,6-hexanediol, 2,2-dimethyl-1 ,3-propanediol, 1 ,2-cyclohexane dimethanol, 1 ,3-cyclohexane dimethanol, 1 ,4-cyclohexane dimethanol, 2, 2,4,4- tetramethyl-1 ,3-cyclobutanediol, isosorbide, p-xylylenediol, and the like. These glycols may also contain ether linkages, such as is the case in, for example, diethylene glycol, triethylene glycol, and tetraethylene glycol. Additional embodiments of glycols include higher molecular weight homologs, known as polyethylene glycols, such as those produced by Dow Chemical Company under the Carbowax™ tradename. In one embodiment, the polyethylene glycol (PEG) has a molecular weight of from greater than 200 to about 10,000 Daltons (Mn). These glycols also include higher order alkyl analogs, such as dipropylene glycol, dibutylene glycol, and the like. Similarly, further glycols include higher order polyalkylene ether diols, such as polypropylene glycol and polytetramethylene glycol with molecular weights ranging from about 200 to about 10,000 Daltons (M _n ) (also referred to as g/mole). In one aspect, the glycol can be chosen from aliphatic, alicyclic, and aralkyl glycols. In various aspects, the glycol can be chosen from ethylene glycol; 1 ,2-propandiol; 1 ,3-propanediol; 1 ,4-butanediol; 1 ,5- pentanediol; 1 ,6-hexanediol; 2, 2-dimethyl-1 ,3-propanediol; 1 ,2-cyclohexane dimethanol; 1 ,3-cyclohexane dimethanol; 1 ,4-cyclohexane dimethanol; 2, 2,4,4- tetramethyl-1 ,3-cyclobutanediol; isosorbide; p-xylylenediol; diethylene glycol; triethylene glycol; tetraethylene glycol; polyethylene glycols; dipropylene glycol; dibutylene glycol; polyalkylene ether diols chosen from polypropylene glycol and polytetramethylene glycol.

In certain aspects, the one or more glycols can include diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4-cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2- methyl-2,4-pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), or a combination thereof; and, optionally, ii) ethylene glycol (EG). In such an aspect, the weight ratio of the glycols of group i) to EG can be of from 100:0 to 1 :99. In certain aspects, the one or more glycols can include about 0 wt. % to about 100 wt. % DEG, or about 1 wt. % to about 100 wt. % DEG, relative to the total weight of the one or more glycols. In certain aspects, the one or more glycols can include about 0 wt. % to about 100 wt. % TEG, or about 1 wt. % to about 100 wt. % TEG, relative to the total weight of the one or more glycols. In aspects, the one or more glycols can include about 0 wt. % to about 50 wt. % CHDM, or about 1 wt. % to about 50 wt. % CHDM, relative to the total weight of the one or more glycols. In various aspects, the one or more glycols can include 0 wt. % to about 100 wt. % PEG, or about 1 wt. % to about 100 wt. % PEG, relative to the total weight of the one or more glycols. In various aspects, the one or more glycols can include 0 wt. % to about 100 wt. % NPG, or about 1 wt. % to about 100 wt. % NPG, relative to the total weight of the one or more glycols. In various aspects, the one or more glycols can include 0 wt. % to about 100 wt. % PDO, or about 1 wt. % to about 100 wt. % PDO, relative to the total weight of the one or more glycols. In various aspects, the one or more glycols can include 0 wt. % to about 100 wt. % BDO, or about 1 wt. % to about 100 wt. % BDO, relative to the total weight of the one or more glycols. In various aspects, the one or more glycols can include 0 wt. % to about 100 wt. % MP diol, or about 1 wt. % to about 100 wt. % MP diol, relative to the total weight of the one or more glycols. In various aspects, the one or more glycols can include 0 wt. % to about 100 wt. % PTMG, or about 1 wt. % to about 100 wt. % PTMG, relative to the total weight of the one or more glycols. In certain aspects, the one or more glycols can include about 0 wt. % to about 100 wt. % EG, or about 1 wt. % to about 100 wt. % EG, relative to the total weight of the one or more glycols. In one aspect, the one or more glycols can include 0 wt. % to about 100 wt. % EG, 0 wt. % to about 100 wt. % DEG, 0 wt. % to about 100 wt. % TEG, 0 wt. % to about 100 wt. % PEG, 0 wt. % to about 100 wt. % NPG, 0 wt. % to about 100 wt. % PDO, 0 wt. % to about 100 wt. % BDO, 0 wt. % to about 100 wt. % MP diol, 0 wt. % to about 100 wt. % PTMG, and 0 wt. % to about 50 wt. % CHDM, relative to the total weight of the one or more glycols. In certain aspects, as discussed in detail below, the one or more glycols can be recycle glycols that were recovered from a prior glycolysis and/or methanolysis process for recovery of one or more dialkyl terephthalates, as disclosed herein.

In various aspects, as discussed above, the glycolysis process can include one or more catalysts, e.g., trans-esterification catalysts. In certain aspects, the catalyst can be present in an amount of from 0.1 wt. % to 10 wt. %, relative to the weight of the polyester composition. In aspects, any suitable catalyst can be utilized. In one aspect, the catalyst can include a carbonate catalyst, for example, but not limited to: Li2CO3, K2CO3, Na2COs, CS2CO3, ZrCOs, or a combination thereof. In one aspect, the catalyst can include a hydroxide catalyst, for example, but not limited to: LiOH, NaOH, KOH, tetrabutylammonium hydroxide (TBAH), or a combination thereof. In one aspect, the catalyst can include an alkoxide catalyst, for example, but not limited to: sodium methoxide (NaOMe), lithium methoxide (LiOMe), magnesium methoxide, potassium t-butoxide, ethylene glycol monosodium salt, ethylene glycol disodium salt, or a combination thereof. In one aspect, the catalyst can include tetra isopropyl titanate (TIPT), butyltin tris-2-ethylhexanoate (FASCAT 4102), 1 ,8-Diazabicyclo[5.4.0]undec- 7-ene (DBU), zinc acetylacetonate hydrate (Zn(acac)2), zinc acetate (Zn(OAc)2), and manganese (II) acetate (Mn(OAc)2)), or a combination thereof. In certain aspects, the catalyst can include LiOH, NaOH, KOH, tetra isopropyl titanate (TIPT), butyltin tris-2- ethylhexanoate (FASCAT 4102), ZrCOs, 1 ,8-Diazabicyclo[5.4.0]undec-7-ene (DBU), sodium methoxide (NaOMe), lithium methoxide (LiOMe), and zinc acetylacetonate hydrate (Zn(acac)2), or a combination thereof. In one aspect, the catalyst can include LiOH, NaOH, KOH, sodium methoxide (NaOMe), and lithium methoxide (LiOMe). In certain aspects, the catalyst can include Li2CO3, K2CO3, CaCOs, Na2COs, CS2CO3, ZrCO3, LiOH, NaOH, KOH, tetrabutylammonium hydroxide (TBAH), sodium methoxide (NaOMe), lithium methoxide (LiOMe), magnesium methoxide (Mg(OMe)2, potassium t-butoxide, ethylene glycol monosodium salt, ethylene glycol disodium salt, tetra isopropyl titanate (TIPT), butyltin tris-2-ethylhexanoate (FASCAT 4102), 1 ,8- Diazabicyclo[5.4.0]undec-7-ene (DBU), zinc acetylacetonate hydrate (Zn(acac)2), zinc acetate (Zn(OAc)2), manganese (II) acetate (Mn(OAc)2), hydrotalcite, zeolite, lithium chloride, or a combination thereof.

The depolymerization conditions can include a temperature of from 150 °C to 260 °C and an absolute pressure of from 1 atmosphere (atm) to 15 atm, or 1 atm to 2 atm, in an agitated reactor for 0.5 h to 10 h. Higher temperatures may be used to increase the rate of depolymerization; however, reactor systems that can withstand elevated pressures may be required. One or a plurality of reactors may be used for the reaction of the polyester with the one or more glycols. For example, the reaction mixture can be continuously withdrawn from the first stage and introduced to a second stage maintained under pressure, along with additional glycol, wherein depolymerization continues to the desired degree of completion. In various aspects, any type of vessel, reactor, and/or reactor system can be utilized for the depolymerization or glycolysis of the polyester composition. In one aspect, a continuous stirred-tank reactor or vessel, a fixed bed reactor, or a melt extruder. In the same or alternative aspects, the depolymerization or glycolysis of the polyester composition can be a batch or continuous process.

Upon exposure to the depolymerization conditions detailed above, the resulting mixture can optionally be allowed to cool to a temperature of about 150 °C or less, or of from about 50 °C to about 150 °C. In aspects, the resulting mixture can be allowed to cool to the desired temperature in the glycolysis reaction vessel(s) or can be transferred to a different vessel for temperature reduction. The resulting mixture can include a solid component and a liquid component. In aspects, the liquid component includes the one or more depolymerization products, e.g., monomers and/or oligomers having a degree of polymerization of from 2 to 10, along with the one or more glycols, and may also include any additional soluble components from the polyester composition, one or more glycols, catalysts, or a combination thereof. In various aspects, the solid component can be the residual foreign materials and/or nonpolyester components and any other insoluble components of the polyester composition and may be considered a waste product to discard.

As discussed further below, the liquid component is further subjected to at least a methanolysis and/or alcoholysis process for the recovery of one or more dialkyl terephthalates. In various aspects, prior to the methanolysis process, the liquid component can be separated from the solid component. In aspects, the liquid component can be separated from the solid component using any system. In one aspect, the liquid component can be separated from the solid component while the resulting mixture is at a temperature of from about 50 °C to about 150 °C. In such aspects, separating the liquid component from the solid component at temperatures of about 150 °C or less, e.g., at about 50 °C to about 150 °C, can provide for a more efficient process and/or less resource intensive process than current conventional processes. In the same or alternative aspects, separating the liquid component from the solid component at temperatures of about 150 °C or less, e.g., at about 50 °C to about 150 °C, can be beneficial as some impurities can be unstable at higher temperatures, e.g., temperatures above 150 °C, which may adversely affect the processes, product yields, and/or product purities described herein.

In various aspects, the separation of the liquid component from the solid component can include a filtration process. In such an aspect, any suitable filtration process can be utilized that is capable of withstanding the increased filtration temperatures of from about 50 °C to about 150 °C. In certain aspects, the solid component can be removed by centrifugation. In certain aspects, the solid can be removed by settling or sedimentation. In certain aspects, the solid component may have settled in the bottom of a vessel allowing for removal of the liquid component through a vessel conduit or valve appropriately positioned within the vessel. In one aspects, such a conduit and/or valve may include a filtration device to minimize the inclusion of solid component in downstream processes.

Alcoholysis of the One or More Depolymerization Products

As discussed above, in aspects, the one or more depolymerization products produced in the glycolysis process described above can be subjected to an alcoholysis process.

Generally, in a typical alcoholysis process, a polyester is reacted with an alcohol, e.g., methanol, to produce a depolymerized mixture comprising oligomers, terephthalate monomers, e.g., dimethyl terephthalate (DMT), and one or more glycols. In other embodiments, other monomers such as, for example, CHDM, DEG, and dimethyl isophthalate (DMI), also may be produced, depending on the composition of the polyester. In one embodiment, during the alcoholysis process the terephthalate oligomers are reacted with methanol to produce a depolymerized polyester mixture comprising polyester oligomers, DMT, CHDM, and/or EG.

Some representative examples of the methanolysis of PET are described in U.S. Pat. Nos. 3,321 ,510; 3,776,945; 5,051 ,528; 5,298,530; 5,414,022; 5,432,203; 5,576,456; 6,262,294; which are incorporated herein by reference.

In aspects, the alcoholysis process can include exposing the liquid component and/or the one or more depolymerization products resulting from the glycolysis process to an alcohol composition under conditions resulting in one or more dialkyl terephthalates. As discussed above, in aspects, the one or more depolymerization products can be present in the liquid component resulting from the glycolysis process. In various aspects, as discussed above, prior to subjecting the one or more depolymerization products and/or the liquid component resulting from the glycolysis process to an alcoholysis process, the liquid component can be separated from the resulting mixture and/or from the resulting solid component of the glycolysis process. In certain aspects, after separating the liquid component from the solid component of the glycolysis process, the liquid component can be directly utilized in this alcoholysis process. In the same or alternative aspects, after separating the liquid component from the solid component of the glycolysis process, the liquid component is not subjected to any further processing, e.g., distillation and/or other separation processes, prior to being utilized in this alcoholysis process. Without being bound by any particular theory, it is believed that since the glycolysis process is performed using a lower amount of glycols compared to certain conventional processes (or a weight ratio of glycols relative to the amount of the polyester composition of from 3:1 to 1 :9) allows for the resulting liquid component from the glycolysis process to be directly utilized in the alcoholysis process without requiring further processing, e.g., to concentrate the resulting one or more depolymerization products and/or remove a portion of the glycols.

The alcohol composition can include any suitable alcohol known in the art for use in an alcoholysis process to obtain a specific dialkyl terephthalate. In one aspect, the alcohol composition can be and/or can include methanol. In aspects, when methanol is utilized as the alcohol composition, DMT can be the resulting methanolysis product.

In certain aspects, the amount of the alcohol composition can be any amount that is in excess on a weight basis relative to the amount or weight of the polyester composition. In certain aspects, a weight ratio of the amount of the alcohol composition relative to the amount of the polyester composition can be from about 2:1 to about 10:1. In various aspects, a weight ratio of the amount of the alcohol composition relative to the amount of the polyester composition can be from about 2:1 to about 9:1 , about 2:1 to about 8:1 , about 2:1 to about 7:1 , about 2:1 to about 6:1 , or about 2:1 to about 5:1 . In aspects, the amount of the polyester composition refers to the amount or weight of the polyester composition that is utilized in the above glycolysis process.

In aspects, the alcoholysis reaction can occur at a temperature of about 90 °C or less, about 80 °C or less, about 70 °C or less, about 60 °C or less, about 50 °C or less, about 40 °C or less, or about 30 °C or less. In the same or alternative aspects, the alcoholysis reaction can occur at a temperature of from about 20 °C to about 90 °C, about 20 °C to about 80 °C, about 20 °C to about 70 °C, about 20 °C to about 60 °C, about 20 °C to about 50 °C, about 20 °C to about 40 °C, or about 20 °C to about 30 °C. In certain aspects, the alcoholysis reaction can occur at a temperature of from about 25 °C to about 90 °C, about 25 °C to about 80 °C, about 25 °C to about 70 °C, about 25 °C to about 60 °C, about 25 °C to about 50 °C, about 25 °C to about 40 °C, or about 25 °C to about 30 °C In various aspects, without being bound by any particular theory, it is believed that, since in the processes disclosed herein, the polyester in the polyester composition has already undergone at least a partial depolymerization process, e.g., in the glycolysis step discussed above, that the methanolysis process can be performed at the temperatures described above, which are comparably reduced compared to certain other conventional processes. Additionally or alternatively, without being bound by any particular theory, it is believed that, since the one or more depolymerization products produced in the glycolysis process are separated from the waste or insoluble material prior to this alcoholysis process, the alcoholysis process can be conducted at the reduced temperatures described above.

In aspects, the alcoholysis process can be conducted in any suitable reactor and/or vessel. In aspects, the alcoholysis reactor can be in fluid communication with the reactor utilized in the glycolysis process described above. In certain aspects, the alcoholysis reactor is a different reactor than the vessel used for glycolysis. Alternatively, in various aspects, the alcoholysis process can be conducted in the same vessel as the glycolysis process and/or the filtration process discussed above. In certain aspects, the alcoholysis process can be conducted at ambient pressure, e.g., about 1 atm, or at a pressure of from about 1 atm to about 5 atm, or of from about 1 atm to about 3 atm, or of from about 1 atm to about 2 atm. In various aspects, the alcoholysis reaction can be conducted at a pressure above ambient pressure, e.g., more than 1 atm, or about 5 atm or less, about 3 atm or less, about 2 atm of less, when the alcoholysis reaction temperature is high for the process conditions disclosed herein, e.g., about 50 °C or more, about 60 °C or more, about 70 °C or more, about 80 °C or more, or about 90°C or more.

In various aspects, an alcoholysis catalyst can be utilized in the alcoholysis process. In aspects, the alcoholysis catalyst can be present in an amount of from about 0.1 wt. % to about 20 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 10 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 5 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 2 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 1 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 0.5 wt. % relative to the weight of the polyester composition. In such aspects, the amount of the polyester composition refers to the amount or weight of the polyester composition that is utilized in the above glycolysis process. In various aspects, the alcoholysis catalyst amounts disclosed in this paragraph refer to the amount of alcoholysis catalyst present during the alcoholysis reaction. In various aspects, the alcoholysis catalyst amounts disclosed in this paragraph refer to the amount of alcoholysis catalysts that is added to one or more depolymerization products and the one or more alcohols to facilitate the alcoholysis reaction. In certain aspects, reduced or lower amounts of alcoholysis catalyst may be added to the one or more depolymerization products and the one or more alcohols to facilitate the alcoholysis reaction, such as an amount of from about 0.1 wt. % to about 10 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 5 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 2 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 1 wt. % relative to the weight of the polyester composition, or of from about 0.1 wt. % to about 0.5 wt. % relative to the weight of the polyester composition. In aspects, such a lower amount of alcoholysis catalysts may be added at least partly because alcoholysis catalyst is already present in the one or more depolymerization products and/or one or more alcohols. In such aspects, as discussed below, the alcohol and/or glycol may be recycled and re-used in subsequent glycolysis and alcoholysis process as disclosed herein, which may include at least a portion of alcoholysis catalyst from a prior alcoholysis and/or glycolysis process.

In various aspects, the alcoholysis catalyst can include a carbonate catalyst, for example, but not limited to: K2CO3, Na2COs, Li2COs, CS2CO3; a hydroxide catalyst, for example, but not limited to: KOH, LiOH, NaOH; an alkoxide catalyst, for example, but not limited to NaOMe, Mg(OMe)2, KOMe, KOt-Bu, ethylene glycol monosodium salt, ethylene glycol disodium salt, or a combination thereof. In certain aspects, the alcoholysis catalyst can include KOH, NaOH, LiOH, or a combination thereof. In certain aspects, the alcoholysis catalyst can include NaOMe, KOMe, Mg(OMe)2, KOt-Bu, ethylene glycol monosodium salt, ethylene glycol disodium salt, or a combination thereof. In various aspects, the alcoholysis catalyst can be in solid form, a solution form in water, methanol, or ethylene glycol, or a combination of thereof. In certain aspects, the alcoholysis catalyst can be added to the one or more depolymerization products and the alcohol composition once the alcohol composition and the one or more depolymerization products reach the desired reaction temperature or temperature range disclosed above.

The one or more depolymerization products can be exposed to the alcohol composition and optionally the alcoholysis catalyst under the temperature and pressure conditions described above for a period of time to achieve the desired yield of the resulting dialkyl terephthalate. In certain aspects, the one or more depolymerization products can be exposed to the alcohol composition and optionally the alcoholysis catalyst under the temperature and pressure conditions described above for a period of time from about 5 minutes to about 5 hours, or of from about 5 minutes to about 2 hours, or about 5 minutes to about 1 hour, or about 5 minutes to about 30 minutes, or about 5 minutes to about 15 minutes, or about 5 minutes to about 10 minutes.

In aspects, the alcoholysis process results in a mixture that includes one or more dialkyl terephthalates. In various aspects, the alcoholysis process results in mixture wherein the dialkyl terephthalate is an insoluble and/or solid component. In aspects, the liquid component of this mixture can include one or more glycols, the alcohol composition, or a combination thereof. In one aspect, the glycols can be the glycols that were utilized in the glycolysis process and present with the one or more depolymerization products at the initiation of the alcoholysis process. In various aspects, the dialkyl terephthalate can be isolated from the mixture using any known separation technique, e.g., filtering, centrifugation, sedimentation, settling, or a combination of one or more separation techniques. In aspects, the filtering may include washing the solid component with additional alcohol composition or other solvent. The resulting liquid component can include the filtrate and wash. The resulting solid component can include about 90 wt. % or more dialkyl terephthalate, e.g., DMT, about 93 wt. % or more dialkyl terephthalate, e.g., DMT, or about 95 wt. % or more dialkyl terephthalate, e.g., DMT, relative to the weight of the solid component. In the same or alternative aspects, the dialkyl terephthalate, e.g., DMT, in the resulting solid component can be about 90 % or more pure, about 93 % or more pure, or about 95 % or more pure. In various aspects, the solid component can also include dimethyl isophthalate (DMI). In such aspects, the DMI can be present in an amount of about 1000 ppm or less, or about 500 ppm or less, or of from about 1 ppm to about 1000 ppm, or of from about 1 ppm to about 500 ppm. In one or more aspects, the solid component can also include bisphenol A (BPA). In such aspects, the BPA can be present in an amount of about 1000 ppm or less, or about 500 ppm or less, or of from about 1 ppm to about 1000 ppm, or of from about 1 ppm to about 500 ppm.

The processes described herein, e.g., the glycolysis and/or alcoholysis processes are substantially mild compared to certain conventional processes, e.g., high temperature one-step glycolysis or methanolysis processes. For instance, certain conventional one-step processes may utilize a glycolysis process at temperatures of 240 °C or above in the presence of a Lewis acid catalyst, for instance, Zn(OAc)2 or KOAc. Such harsh conditions can result in reduced EG yield from the depolymerization, as the EG is converted in various side reactions to various impurity compounds, including but not limited to: diethylene glycol (DEG), triethylene glycol (TEG), acetaldehyde, 1 ,1 -dimethoxyethane, 1 ,2-dimethoxyethane, dioxane, 2- methoxyethanol, 1 -methoxyethanol, and dimethyl ether. In aspects, the processes described herein are substantially milder than such conventional processes, and also result in less EG yield loss, e.g., from less side reactions converting EG into various impurities. In one aspect, the processes described herein result in about 5 % or less yield loss of EG, about 2 % or less yield loss of EG, or about 1 % or less yield loss of EG, or about 0.5 % or less yield loss of EG. In such aspects, the yield loss of EG is the percent of EG that is formed into impurities, e.g., DEG, relative to the combined amount of EG from the polyester composition feed and of the EG added in the glycolysis process. In the same or alternative aspects, the processes described herein result in minimal glycol impurities being produced. For instance, in one aspect, the processes described herein can result in the net generation of about 5 wt. % or less DEG, about 2 wt. % or less DEG, or about 1 wt. % or less DEG, or about 0.5 wt. % or less DEG, or of from about 0.01 wt. % to about 5 wt. % DEG, about 0.01 wt. % to about 2 wt. % DEG, or about 0.01 wt. % to about 1 wt. % DEG, or about 0.01 wt. % to about 0.5 wt. % DEG, or about 0.01 wt. % to about 0.2 wt. % DEG, when EG is used as the one or more glycols in the glycolysis process. In aspects, the processes described herein can result in the net generation of about 5 wt. % or less DEG and/or other impurity, about 2 wt. % or less DEG and/or other impurity, or about 1 wt. % or less DEG and/or other impurity, or about 0.5 wt. % or less DEG and/or other impurity, or of from about 0.01 wt. % to about 5 wt. % DEG and/or other I impurity, about 0.01 wt. % to about 2 wt. % DEG and/or other impurity, or about 0.01 wt. % to about 1 wt. % DEG and/or other impurity, or about 0.01 wt. % to about 0.5 wt. % DEG and/or other impurity, or about 0.01 wt. % to about 0.2 wt. % DEG and/or other impurity, when EG is used as the one or more glycols in the glycolysis process. In aspects, the net generation of DEG (or other impurity) is the weight percent of the amount of DEG or other impurity that is present over the amount of DEG or other impurity present in the polyester composition feed. In one aspect, the DEG being produced can be produced in the glycolysis process described herein and/or the alcoholysis process described herein. In certain aspects, the EG and/or any glycol impurities, such as DEG when using EG as the one or more glycols in the glycolysis process, can be present in the resulting liquid component from this alcoholysis step. In certain aspects, utilization of a Lewis base catalyst, e.g., a hydroxide-based or carbonate-based catalyst, in the glycolysis process may also facilitate or contribute to reduced EG degradation and/or a reduction of glycol impurities.

Recycling Glycols and Alcohol Composition

As discussed above, in various aspects, the glycols utilized in the glycolysis process can be re-used in subsequent rounds of processes for recovery of one or more dialkyl terephthalates disclosed herein. At a high level, in aspects, the liquid component resulting from the alcoholysis process can be processed for re-use, e.g., for re-use in subsequent rounds of glycolysis and/or methanolysis of a subsequent polyester composition to recover one or more dialkyl terephthalates. In the same or alternative aspects, methanol can be recovered from the liquid component resulting from the alcoholysis process and can be re-used, e.g., in subsequent alcoholysis processes described above. In such an aspect, the methanol can be recovered by exposing the liquid component to distillation conditions.

In aspects, as discussed above, the liquid component resulting from the alcoholysis process can include the glycols used in the glycolysis process, the alcohol composition, and glycols generated in the glycolysis process, e.g., EG, DEG, and/or CHDM. In various aspects, this liquid component can be subjected to a separation process, e.g., to remove or separate at least a portion of the alcohol composition, for instance, methanol. In certain aspects, for removal of at least a portion of the alcohol composition, the liquid component can be exposed to distillation or short path distillation. In example non-limiting aspects, the distillation conditions may include exposing the liquid component to a temperature of about 260 °C or less, about 220 °C or less, about 200 °C or less, about 180 °C or less, about 160 °C or less, about 150 °C or less, about 130 °C or less, about 60 °C or more, about 70 °C or more, of from about 60 °C to about 220 °C, of from about 70 °C to about 220 °C, of from about 60 °C to about 180 °C, or of from about 60 °C to about 160 °C. In the same or alternative aspects, the distillation conditions can include a pressure of from about 1 Torr (133.3 Pa) to about 800 Torr (106,657 Pa), or about 30 Torr (3999 Pa) to about 500 Torr (66,661 Pa). In aspects, the liquid component can be exposed to the distillation conditions until all or a substantial portion of the alcohol composition has been removed, e.g., vaporized, from the liquid component. In certain aspects, the recovered alcohol from the liquid component, e.g., methanol, can be returned to the alcoholysis reaction vessel for use in subsequent alcoholysis processes and/or returned to a glycolysis reaction vessel for use in a glycolysis process as described above.

In aspects, the distillation of the liquid component can occur in any vessel or distillation system that is suitable for use in the processes and systems described herein. In one aspect, the distillation vessel can be in fluid communication with the alcoholysis reaction vessel and/or any component of the filtering process utilized subsequent to the alcoholysis, e.g., to isolate the dialkyl terephthalate solid or insoluble component. In the same or alternative aspects, the distillation vessel can be in fluid communication with the glycolysis vessel.

In various aspects, the distillation of the liquid component can cause the alcohol composition to vaporize leaving a pot residue. In various aspects, the pot residue includes the glycols and any other heavies, e.g., non-vaporizable compounds present in the liquid component. In aspects, the glycols in the pot residue can be referred to as recycle glycols and/or the glycols from a non-vaporizable portion of a continuous distillation process using the distillation conditions described herein can be referred to as recycle glycols. In one aspect, the recycle glycols can include ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4- cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2-methyl-2,4-pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), or a combination thereof.

In aspects, as discussed above, the recycle glycols can be utilized in a subsequent round of the process described herein to recover one or more dialkyl terephthalates from a polyester composition. Further, in aspects, the recycle glycols can be recycled again using the process described herein, after going through this subsequent round of dialkyl terephthalate recovery. In aspects, the recycle glycols can be recovered and re-used at least two, at least three, at least four, or at least five times. In certain aspects, when the recycle glycols are used in subsequent round(s) of dialkyl terephthalate recovery, addition of a catalyst in the subsequent glycolysis step(s) may be omitted, as the recycle glycols may include prior-used catalyst.

In aspects, when the recycles glycols are recovered and re-used, it has been unexpectedly found that the resulting dialkyl terephthalates recovered exhibit comparable purity to that of dialkyl terephthalates recovered using glycols that have not been recovered and re-used. This comparable purity of the dialkyl terephthalate is present, in aspects, after re-using recycle glycols at least two times, at least three times, at least four times, or at least five times resulting in a dialkyl terephthalate recovery having a purity of at least about 90 %, at least about 93 %, or at least about 95 %.

Example Systems

FIG. 1 schematically depicts one example system and/or process for recovering polyesters from a feedstock composition and optionally depolymerizing at least a portion of the recovered polyester. The system 100 may include a source 1 10 of a feedstock composition. In the vessel 120, the feedstock composition is exposed to one or more solvents to dissolve at least a portion of the polyester component and/or at least a portion of the non-polyester component. In one example aspect, the solvent can be 4-methylcyclohexanemethanol (MCHM), ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4-cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2-methyl-2,4-pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), or a combination thereof. In the same or alternative aspects, the solvent and the feedstock composition can be exposed to a temperature of from 150 °C to 300 °C thereby allowing the polyester to dissolve while at least a portion of the non-polyester components remain insoluble. In the aspect depicted in FIG. 1 , the system 100 also includes a solid-liquid separation system 130, where the dissolved polyester, e.g., a polyester liquid component in the solvent, can be separated from the insoluble components, e.g. the insoluble non-polyester components. In aspects, the solid-liquid separation system 130 need not be separate from the vessel 120, or may be separate from the vessel. In the aspect depicted in FIG. 1 , the solid-liquid separation system 130 of FIG. 1 is meant to represent the solidliquid separation processes described above. The solid-liquid separation can occur at a temperature of from 150 °C to 300 °C, e.g., to maintain the polyester in a dissolved state. The system 100 also includes a cooling system 140, where the dissolved polyester, e.g., a polyester liquid component in the solvent, is cooled to a temperature of 50 °C or below, in order to precipitate the polyester component in the solvent. In aspects, the cooling system 140 need not be separate from the vessel 120 or the solidliquid separation system 130 and/or 150, or may be a separate vessel. In the aspect depicted in FIG. 1 , the system 100 also includes a solid-liquid separation system 150 for recovering the polyester component e.g., separating the polyester component from the solvent. In the aspect depicted in FIG. 1 , the system 100 optionally includes a depolymerization process 160. The depolymerization process 160 can include any or all of the parameters mentioned above with respect to the depolymerization processes. For instance, the depolymerization process may be utilized to recover one or more dialkyl terephthalates, EG, or both.

FIG. 2 depicts another example system 200 and/or process for recovering polyesters from a feedstock composition and optionally depolymerizing at least a portion of the recovered polyester. The system 200 may include a source 210 of a feedstock composition. In the vessel 220, the feedstock composition is exposed to one or more first solvents to dissolve at least a first portion of the non-polyester component and/or melt at least a second portion of the non-polyester component. In one example aspect, the first solvent can include dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), tetrahydrofuran (THF), ethanol, 2-ethyl hexanol (2-EH), 4- methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof. In the same or alternative aspects, the first solvent and the feedstock composition can be exposed to a temperature of from 70 °C to 200 °C thereby dissolving at least a first portion of the non-polyester component and/or melting at least a second portion of the non-polyester component, while the polyester component may stay intact, e.g., insoluble. In the aspect depicted in FIG. 2, the system 200 also includes a solid-liquid separation system 230. In the aspect depicted in FIG. 2, the solid-liquid separation system 230 of FIG. 2 is meant to represent the solid-liquid separation processes described above. In aspects, the solid-liquid separation system 230 need not be separate from the vessel 220, or may be separate from the vessel. In one example aspect, the solid-liquid separation may remove a floating layer of polyolefins, polyethylene, polypropylene, polystyrene, or a combination thereof, when exposed to the example solvents and conditions mentioned in this paragraph. In the same or alternative aspects, the solidliquid separation system 230 may remove the insoluble polyester component, e.g., at a temperature of from 70 °C to 200 °C, from the solvent. In such an aspect, at the conditions and solvents mentioned in this paragraph the non-polyester components: polyvinyl chloride (PVC), polyvinyl acetal, polyvinyl butyral (PVB), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), or a combination thereof, may be present and dissolved in the solvent and thus thereby separated from the polyester. In the aspect depicted in FIG. 2, the system 200 includes a vessel 240 for exposing the polyester component to a second solvent, e.g., to dissolve at least a portion of the polyester. In one example aspect, the second solvent can include 4-methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof and the polyester and second solvent may be exposed to a temperature of from 150 °C to 300 °C. In aspects, the vessel 240 may be the same vessel as any of the other systems described above with reference to FIG. 2. In the aspect depicted in FIG. 2, the system 200 includes a solidliquid separation system 250 for separating a third portion of the non-polyester components from the dissolved polyester. In such aspects, and under solvents and conditions described in this paragraph, nylon and/or cotton can be in an insoluble state and be separated from the dissolved polyester at this stage. In such aspects, the solidliquid separation system 250 can separate the third portion of the non-polyester components from the dissolved polyester at a temperature of from 150 °C to 300 °C. The system 200 also includes a cooling system 260, where the dissolved polyester, e.g., a polyester liquid component in the solvent, is cooled to a temperature of 50 °C or below, in order to precipitate the polyester component in the solvent. In aspects, the cooling system 260 need not be separate from the vessel or systems 220, 230, 240, 250, or 270, or may be a separate vessel. In the aspect depicted in FIG. 2, the system 200 also includes a solid-liquid separation system 270 for recovering the polyester component e.g., separating the polyester component from the solvent. In the aspect depicted in FIG. 2, the system 200 optionally includes a depolymerization process 280. The depolymerization process 280 can include any or all of the parameters mentioned above with respect to the depolymerization processes. For instance, the depolymerization process may be utilized to recover one or more dialkyl terephthalates, EG, or both.

Use of Recovered Dialkyl Terephthalates to Form Polyesters or Other Products

As discussed above, the processes disclosed herein can result in high purity dialkyl terephthalates, such as DMT. For instance, in certain aspects, the recovered DMT can be utilized to form one or more polyesters, including but not limited to PET and/or TMCD-containing polyesters. In various aspects, the products formed using the recovered DMT may be indistinguishable from similar products formed from virgin DMT. In such aspects, any suitable process for forming the PET and TMCD- containing polyesters can be utilized, since the DMT is of sufficient purity.

In the same or alternative aspects, the recovered DMT can be utilized to form CHDM. In various aspects, the CHDM formed using recovered DMT may be indistinguishable from CHDM formed from virgin DMT, due to the high purity of the recovered DMT. In such aspects, the CHDM can be formed from the recovered DMT using any suitable process. The present disclosure can be further illustrated by the following examples of aspects thereof, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the disclosure unless otherwise specifically indicated.

EXAMPLES

Materials

FDST-5 contains 100 mole % TPA, 93.0 mole % EG, 4.1 mole % CHDM, and 2.9 mole % DEG, and is available from Eastman. IV: 0.751 dL/g.

FDST-52 carpet powder contains 54.6% TPA and 12.9 ppm BPA by LC- hydrolysis analysis. The sample is obtained from Circular Polymers.

FDST-101 carpet pellet contains 73.1% TPA and 33.5 ppm BPA by LC- hydrolysis analysis. The sample is obtained from Circular Polymers.

All other chemicals and reagents were obtained from Aldrich and used as received, unless otherwise mentioned.

Analytical Procedures

Gas Chromatography (GO Analysis. GC analysis was performed on an Agilent model 7890B gas chromatograph equipped with a 7693A autosampler and two G4513A towers. The gas chromatograph (GC) was outfitted with two columns — a 60m x 0.32mm x 1 .0 micron DB-1701 ™ (J&W 123-0763) and a 60m x 0.32 x 1 micron DB- 1 ™ (J&W 123-1063) — and samples were injected simultaneously onto both columns. A shared oven temperature program was used, and sample components were detected by flame ionization detection (FID). Five-point calibrations were performed for components of interest. The gas chromatograph was interfaced to an EZChrom Elite Chromatography Data System.

Methanolysis product samples were prepared by adding a known volume of pyridine-based internal standard solution to a known mass of sample and then derivatizing with N,0-Bis(trimethylsilyl)trifluoroacetamide (BSTFA). MHT (4- (methoxycarbonyl) benzoic acid) GC wt. % and MHET (Methyl-2-hydroxyethyl terephthalate) GC wt. % are provided as a read-out from the GC process software. Liquid Chromatography (LC). LC analysis for PET was performed on an HP 1100 series liquid chromatograph equipped with diode array detector (DAD, 240 and 360 nm) . The system was fitted with a Agilent Poroshell EC-C18 (4.6 x 150 mm, 2.7 pm) column at 30 °C and 600 bar pressure. The flow rate was 0.9 mL/min. Mobile phases were 0.14% phosphoric acid in water (A), acetonitrile (B), and THF (C). The elution gradient was as follows: 0 min, 79% A 10% B 121% C; 10 min, 79% A 10% B / 21% C; 18 min, 34% A / 45% B / 21% C; 18.1 min, 14% A / 65% B / 21% C; 19 min, 14% A I 65% B I 21% C; 19.1 min, 79% A I 0% B I 21% C; 25 min, 79% A I 0% B I 21% C. Sample solution was prepared by dissolving ~4 mg sample in 1 mL DMF/DMSO (50/50). The injection volume was 5 pL. TPA content was reported as wt%.

PET sample was analyzed by hydrolyzing PET into TPA. Mix 0.05 (± 0.01 g) sample with 5 mL DMSO and 5 mL tetramethylammonium hydroxide (TMAH) reagent (prepared by mixing TMAH/MeOH solution (25 wt%) and DMSO at 40/60 volume ratio). The resulting mixture in an 8-dram vial was heated at 121 °C for 15 minutes. Cool down to ambient temperature. Neutralize the mixture by adding 5 mL acetic acid in DMSO solution (30% by volume). Further dilute with more DMSO if necessary. PET content (wt %) was calculated from the equation below.

TPA wt%

PET content (wt%) = 86.4% ( theoretical value in pure PET

LC analysis for BPA was performed on an HP 1100 series liquid chromatograph equipped with a fluorescence detector using excitation wavelength of 225 nm, emission wavelength of 310 nm, a FLD PMT gain of 10 and data frequency of 2.31 Hz. The system was fitted with an Agilent Poroshell EC-C18 (4.6 x 150 mm, 2.7 pm) column at 30 °C. Mobile phases were 0.14% phosphoric acid in water (A), acetonitrile (B) and THF (C). The elution gradient was as follows: 0 min, 79% A / 0% B 121% C; 10 min, 79% A 10% B 121% C; 18 min, 34% A 145% B 121% C; 18.1 min, 14% A I 65% B I 21% C; 19 min, 14% A I 65% B I 21% C; 19.1 min, 79% A I 0% B I 21% C; 25 min, 79% A I 0% B I 21% C. The flow rate was 0.9 mL/min. BPA content was reported ppm (pg/g). Gel Permeation Chromatography (GPC). Size exclusion chromatography GPC analysis was performed on an Agilent series 1100 GPC/SEC analysis system with a UV-Vis detector. The column set used was Polymer Laboratories 5 pm Plgel, with guard, mixed C and oligopore. The eluent consists of 95% methylene chloride and 5% hexafluoroisopropanol with tetraethylammonium nitrate (1 gram / 2 liter solvent). The testing was performed at ambient temperature with a flow rate of 1.0 mL/min. Instrument was calibrated with linear PET oligomer standard.

Sample was prepared by dissolving 10 mg sample in 10 mL methylene chloride/hexafluoroisopropanol (70/30). 10 pL Toluene was added as flow rate marker. The injection volume was 10 pL.

DMT (dimethyl terephthalate) % yield was calculated as: (weight of final DMT) I (theoretical DMT weight) * 100%.

DMT GC purity% was calculated as: (weight% of DMT in final product by GC) I (total wt. % by GC) * 100%.

Inherent Viscosity Measurement. The Inherent viscosities (IV) of the particular polymer materials useful herein are determined according to ASTM D2857- 70 procedure, in a Wagner Viscometer of Lab Glass, Inc., having a ¹ /2 mL capillary bulb, using a polymer concentration about 0.5% by weight in 60/40 by weight of phenol/tetrachloroethane. The procedure is carried out by heating the polymer/solvent system at 120°C for 15 minutes, cooling the solution to 25°C and measuring the time of flow at 25°C. The IV is calculated from the equation: l 7n - - inh Q where: q: inherent viscosity at 25°C at a polymer concentration of 0.5 g/100 mL of solvent; ts: sample flow time; to: solvent-blank flow time; C: concentration of polymer in grams per 100 mL of solvent. The units of the inherent viscosity throughout this application are in the deciliters/gram.

Viscosity can be measured in tetrachloroethane/phenol (50/50, weight ratio) at 30°C and calculated in accordance with the following equation: wherein i _sp is a specific viscosity and C is a concentration.

Example 1 : Polymer Solubility Tests In this Example 1 , polymers (1 g) and solvents (9 g) (for 10 wt. % polymer) [or 2g polymer and 8 g solvent for 20 wt. % polymer] were charged into a 20- mL vial with a magnetic stirring bar. The resulting mixture was heated in a heating block at a set temperature and stirred for 4 hours. Record the dissolution temperature. Dissolution was visually observed. The result was summarized in Table 1 below. Table 1 : Polymer Dissolution in Example 1

PET from the dissolution experiments of Example 1 were analyzed by GPC. As shown below in Table 2, the PET stayed almost intact under the dissolution conditions. Table 2: GPC Analysis of PET dissolution in Example 1

Example 2: Impurity Spiking Tests A 20-mL vial with a magnetic stirring bar was charged with PET (1 g), impurity polymer (1 g) and solvent (9 g). The impurity polymer is the materials/polymers listed in Table 3 that are not PET: polyvinyl chloride, polypropylene, nylon-6, 6. The resulting mixture was heated to the set temperature. As shown in Table 3 below, DBT was demonstrated to separate PET from a mixture of PET/PVC/PP. At 95 °C, PVC dissolved in DBT, while PP stayed afloating and PET stayed in the bottom. MCHM was shown to dissolve PET and melt PP at 210 °C, while nylon-6, 6 stayed intact.

Table 3 Impurity Spiking Test Results Example 3: PET Depolymerization with a 4:1 wt. ratio of EG and Methanol at 195 °C

A 100 mL autoclave was equipped with a mechanical stirrer, thermocouple, gas inlet, and vent. FDST-5 (15.01 g), ethylene glycol (24.48 g), methanol (6.07 g), potassium carbonate (0.1504 g) was charged to the reactor. The vessel was pressurized to 150 psig using nitrogen and the mixture was heated to 195°C. Once internal temperature reached 195°C, the pressure was adjusted to 750 psig. The conditions were held for 3 hours. The crude mixture was allowed to cool to 25°C and pressure was released. GC analysis showed that crude mixture contained 16.2% BHET, 15.7% MHET and 3.8% DMT.

Example 4: Dissolution with dibutyl terephthalate (DBT) or ethylene carbonate (EC)

A 3-necked 1 -liter round-bottom flask was equipped with a mechanical stirrer, a reflux condenser and a thermocouple. Charge FDST-52 (50.45 g) and dibutyl terephthalate (DBT, 579 g). The resulting mixture was heated to 240 °C under nitrogen atmosphere and hold for 8 h. Stop the agitation and let the insolubles settle to the bottom. Decant the clear liquid at 230 °C into aluminum pan. After aluminum pan was cooled to ambient temperature, PET was isolated by filtration and washed with -200 mL isopropanol. PET was obtained as powder (36.01 g, 70.9% LC purity). Insoluble was isolated (8.80 g). Similarly, FDST-5 was treated in DBT at 240 °C. PET was obtained in 97.3% mass balance with 94.5% LC purity. (Example 4-2 and 4-4 used a 1 -liter autoclave instead of round-bottom flask. Similar result was obtained).

A 3-necked 1 -liter round-bottom flask was equipped with a mechanical stirrer, a reflux condenser and a thermocouple. Charge FDST-5 (50 g) and ethylene carbonate (EC, 450 g). The resulting mixture was heated to 188 °C under nitrogen atmosphere and hold for 1 h. Stop the agitation and decant the hot solution into aluminum pan. After aluminum pan was cooled to ambient temperature, PET was isolated by filtration and washed with -200 mL isopropanol . PET was obtained as powder (45.92 g, 94.2% LC purity). FDST-52 was also treated with ethylene carbonate at 188 °C. However, due to high density of ethylene carbonate, insolubles suspended in the ethylene carbonate solution and did not settle to the bottom. The results are summarized in Table 4 below.

Table 4: DBT Dissolution Tests Example 5: Methanolysis of Various Feedstocks and PET-purified Feedstocks

A 100-mL autoclave was charged with FDST-5 pellet (15.0 g) (or 15 g of the feedstocks listed below in Table 5), methanol (45.0 g) and zinc acetate (0.15 g). The resulting mixture was heated to 260 °C and stirred for 4 hours. After completion, the autoclave was allowed to cool to ambient temperature. Crude reaction mixture was taken up in dichloromethane (100 mL) and washed with water. The organic layer was dried over sodium sulfate and concentrated. DMT product was obtained as off-white solid (14.1 g, 93.0% yield, 88.3% GC purity) for the FDST-5.

Both unpurified feedstocks and solvent-purified PET were subjected the autoclave methanolysis at 260 °C. As shown below, DMT was isolated at an improved mass balance after the purification by dissolution. The purity profile is comparable for unpurified and solvent-purified PET. As can be seen in the results provided in Table 5, the processes disclosed herein provide effective dissolution of PET with improved PET purity, thereby providing good DMT yield upon recovery from the purified PET. Table 5: Methanolysis of Various Feedstocks and PET-purified Feedstocks Results The present disclosure can also be described in accordance with the following numbered clauses.

Clause 1 . A process for recovering one or more polyesters from a feedstock composition, comprising: exposing a feedstock composition to a solvent, wherein the feedstock composition comprises one or more polyesters and one or more non-polyester components, and wherein the solvent is selected from the group consisting of 4-methylcyclohexanemethanol (MCHM), ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), 1 ,4-cyclohexanedimethanol (CHDM), polyethylene glycol) (PEG), neopentyl glycol (NPG), propane diol (PDO), butanediol (BDO), 2-methyl-2,4-pentanediol (MP diol), poly(tetramethylene ether)glycol (PTMG), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), or a combination thereof, and wherein the exposing occurs at a temperature of from 150 °C to 300 °C to dissolve at least a portion of the one or more polyesters from the feedstock composition in the solvent, thereby forming a polyester liquid component; separating at least a portion of the one or more nonpolyester components from the polyester liquid component, wherein the separating occurs at a temperature of from 150 °C to 300 °C; cooling the polyester liquid component to a temperature below 50 °C; and recovering the at least a portion of the one or more polyesters from the polyester liquid component by a solid-liquid separation.

Clause 2. The process of clause 1 , wherein the one or more polyesters are present in the feedstock composition in a range of from 10 wt. % to 99 wt. %.

Clause s. The process of clauses 1 -2, wherein the non-polyester components comprise at least one member selected from the group consisting of cotton, polycarbonate, Spandex, natural fibers, cellulose ester, polyacrylates, polymethacrylate, polyamides, nylon, poly(lactic acid), polydimethylsiloxane, polysilane, calcium carbonate, titanium dioxide, inorganic fillers, dyes, pigments, color toners, colorants, plasticizers, adhesives, flame retardants, metals, aluminum, and iron.

Clause 4. The process of clauses 1 -3, wherein the non-polyester components are present in the feedstock composition in an amount of from 0.01 wt. % to 50 wt. %, relative to the weight of the one or more polyesters.

Clause 5. The process of clauses 1 -4, wherein the solvent is selected from the group consisting of 4-methylcyclohexanemethanol (MCHM), dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), ethylene carbonate (EC), dimethyl carbonate (DMC), or a combination thereof, and optionally ethylene glycol (EG).

Clause 6. The process of clauses 1 -5, wherein, subsequent to the separating at least a portion of the one or more non-polyester components from the polyester liquid component, the at least a portion of the one or more polyesters exhibits a weight average molecular weight (Mw) that is at least 50 % of the weight average molecular weight of the one or more polyesters in the feedstock composition.

Clause 7. The process of clauses 1 -6, wherein the one or more polyesters comprises polyethylene terephthalate (PET), 1 ,4-cyclohexanedimethanol (CHDM)-modified PET, isophthalic acid (IPA)- modified PET, diethylene glycol (DEG)- modified PET, neopentyl glycol (NPG)-modified PET, propane diol (PDO)-modified PET, butanediol (BDO)-modified PET, heaxanediol (HDO)-modified PET, 2-methyl- 2,4-pentanediol (MP diol)-modified PET, isosorbide-modified PET, polycyclohexylenedimethylene terephthalate (PCT), cyclohexanedimethanol (CHDM)- containing copolyester, isosorbide-containing copolyester, or a combination thereof.

Clause 8. The process of clauses 1 -7, wherein the one or more polyesters comprises 0 mole % to 100 mole % CHDM, 0 mole % to 100 mole % DEG, 0 mole % to 100 mole % NPG, 0 mole % to 100 mole % PDO, 0 mole % to 100 mole % BDO, 0 mole % to 100 mole % HDO, 0 mole % to 100 mole % MP diol, 0 mole % to 100 mole % isosorbide, and 0 mole % to 30 mole % isophthalic acid, wherein the sum of diol equivalents in the one or more polyesters is about 100 mole %, and wherein the sum of diacid equivalents in the one or more polyesters is about 100 mole %.

Clause 9. The process of clauses 1 -8, wherein at least one of the one or more polyesters has an inherent viscosity of from about 0.1 dL/g to about 1 .2 dL/g, as determined according to ASTM D2857-70.

Clause 10. The process of clauses 1 -9, wherein the one or more polyesters can comprise textiles, carpet, thermoformed materials, bottles, pellets, and film.

Clause H . The process of clauses 1 -10, wherein the cooling the polyester liquid component to a temperature below 50 °C comprises cooling the polyester liquid component to a temperature of from 20 °C to 50 °C.

Clause 12. The process of clauses 1 -1 1 , further comprising: exposing the at least a portion of the one or more polyesters to a depolymerization process to recover one or more dialkyl terephthalates, ethylene glycol (EG), or both.

Clause 13. The process of clause 12, wherein the depolymerization process comprises an initial depolymerization step, an alcoholysis step, or both.

Clause 14. The process of clause 13, wherein the depolymerization process comprises the initial depolymerization step, and wherein depolymerization step comprises exposing the at least a portion of the one or more polyesters to one or more glycols and a depolymerization catalyst under depolymerization conditions, the depolymerization conditions comprising a temperature in a range of about 120 °C to about 260 °C, a pressure in a range of about 0.013 atm (0.2 psig) to about 2 atm (30 psig), and a time period in a range of about 0.5 hours to about 10 hours.

Clause 15. The process of clauses 13-14, wherein the depolymerization process comprises the alcoholysis step, and wherein the alcoholysis step is conducted at a temperature from 23 °C to 70 °C for 0.5 hours to 10 hours.

Clause 16. The process of clause 15, wherein the alcoholysis step comprises exposing depolymerization products from the depolymerization process to one or more alcohols and an alcoholysis catalyst.

Clause 17. The process of clauses 12-16, wherein the depolymerization process comprises recovering the one or more dialkyl terephthalates, and wherein the one or more dialkyl terephthalates comprise dimethyl terephthalate (DMT), and wherein the DMT is at least 90 % pure.

Clause 18. The process of clause 17, wherein the DMT is used in a subsequent polymerization process to form at least one polyester.

Clause 19. The process of clauses 12-18, wherein the depolymerization process comprises recovering EG from the at least a portion of the one or more polyesters, wherein the EG is used in a subsequent polymerization process.

Clause 20. The process of clauses 1 -19, wherein the process is conducted as a batch process, a semi-continuous process, or a continuous process.

Clause 21. The process of clauses 1 -20, wherein the solid-liquid separation comprises filtration, centrifugation, settling, sedimentation, or a combination thereof.

Clause 22. A process for recovering one or more polyesters from a feedstock composition, comprising: exposing a feedstock composition to a first solvent, the first solvent comprising dibutyl terephthalate (DBT), dioctyl terephthalate (DOTP), tetrahydrofuran (THE), ethanol, 2-ethyl hexanol (2-EH), 4- methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, wherein the feedstock composition comprises one or more polyesters and one or more non-polyester components, and wherein the exposing occurs at a temperature of from 70 °C to 200 °C to dissolve at least a first portion of the non-polyester components; separating at least the first portion of the non-polyester components from the one or more polyesters, wherein the separating occurs at a temperature of from 70 °C to 200 °C; exposing the one or more polyesters to a second solvent, the second solvent comprising 4-methylcyclohexanemethanol (MCHM), dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethyl terephthalate (DMT), or a combination thereof, to dissolve at least a portion of the one or more polyesters thereby forming a polyester liquid component, wherein the exposing occurs at a temperature of from 150 °C to 300 °C; and recovering the at least a portion of the one or more polyesters from the polyester liquid component by a solid-liquid separation.

Clause 23. The process of clause 22, wherein the non-polyester components comprise polyolefins, polyethylene, polypropylene, polystyrene, polyvinyl chloride (PVC), polyvinyl acetal, polyvinyl butyral (PVB), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), or a combination thereof.

Clause 24. The process of clauses 22-23, wherein the first portion of the non-polyester components comprises polyvinyl chloride (PVC), polyvinyl acetal, polyvinyl butyral (PVB), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), or a combination thereof.

Clause 25. The process of clauses 22-24, wherein, during the exposing the one or more polyesters to a second solvent, a second portion of non- polyester components is present, and wherein the second portion of non-polyester components is insoluble.

Clause 26. The process of clause 25, wherein the second portion of non-polyester components comprises nylon.

Clause 27. The process of clauses 22-26, wherein the recovering the at least a portion of the one or more polyesters from the polyester liquid component by a solid-liquid separation comprises performing a solid-liquid separation at a temperature of 100 °C or less to recover the one or more polyesters from the second solvent.

Clause 28. The process of clauses 22-27, further comprising: exposing the at least a portion of the one or more polyesters to a depolymerization process to recover one or more dialkyl terephthalates, ethylene glycol, or both. Clause 29. The process of clause 28, wherein the depolymerization process comprises an initial depolymerization step, an alcoholysis step, or both.

Clause 30. The process of clause 29, wherein the depolymerization process comprises the initial depolymerization step, and wherein depolymerization step comprises exposing the at least a portion of the one or more polyesters to one or more glycols, and a depolymerization catalyst under depolymerization conditions, the depolymerization conditions comprising a temperature in a range of about 120 °C to about 260 °C, a pressure in a range of about 0.013 atm (0.2 psig) to about 2 atm (30 psig), and a time period in a range of about 0.5 hours to about 10 hours.

Clause 31. The process of clauses 29-30, wherein the depolymerization process comprises the alcoholysis step, and wherein the alcoholysis step is conducted at a temperature from 23 °C to 70 °C for 0.5 hours to 10 hours.

Clause 32. The process of clause 31 , wherein the alcoholysis step comprises exposing depolymerization products from the depolymerization process to one or more alcohols and an alcoholysis catalyst.

Clause 33. The process of clauses 28-32, wherein the depolymerization process comprises recovering the one or more dialkyl terephthalates, and wherein the one or more dialkyl terephthalates comprise dimethyl terephthalate (DMT), and wherein the DMT is at least 90 % pure.

Clause 34. The process of clause 33, wherein the DMT is used in a subsequent polymerization process to form at least one polyester.

Clause 35. The process of clauses 28-34, wherein the depolymerization process comprises recovering the EG, wherein the EG is used in a subsequent polymerization process.

Clause 36. The process of clauses 22-35, wherein the process is conducted as a batch process, a semi-continuous process, or a continuous process.

Clause 37. The process of clauses 22-36, wherein the solid-liquid separation comprises filtration, centrifugation, settling, sedimentation, or a combination thereof.

This disclosure has been described in detail with particular reference to specific aspects thereof, but it will be understood that variations and modifications can be made within the spirit and scope of this disclosure.