Terephthalic acid ester formation

Abstract

To provide a process for transforming polyethylene terephthalate or poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) into terephthalate.SOLUTION: Provided is a process for transformation into terephthalate of Formula (I) (where R1 and R2 are independently selected from the group consisting of hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 hydroxyalkyl, optionally substituted C3-C8 cycloalkyl, optionally substituted (C1-C6 alkyl)(C3-C8 cycloalkyl), optionally substituted aryl, and optionally substituted (C1-C6 alkyl)(aryl); provided that one of R1 or R2 is not hydrogen), the process comprising the step of admixing the polyester with a mixture comprising: (a) solvent for swelling the polyester; (b) an alcoholic solvent; and (c) a sub-stoichiometric amount of an alkoxide.SELECTED DRAWING: None

Description

[Technical field]

[0001] cross reference This patent application claims the benefit of U.S. Application No. 15 / 706,484, filed September 15, 2017, which is incorporated herein by reference in its entirety.

[0002] This disclosure relates to the formation of ester derivatives from polyesters, and more specifically, to the formation of terephthalic acid esters from polyethylene terephthalate (PET) or poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG). This disclosure also relates to the formation of dimethyl terephthalate (DMT). This disclosure also relates to the formation of monoethylene glycol (MEG). [Background technology]

[0003] The market for polyethylene terephthalate (PET) bottle resin has experienced strong growth as PET resin replaces glass in carbonated soft drinks, bottled water and food containers.

[0004] Dimethyl terephthalate (DMT) is used primarily in the production of polyethylene terephthalate (PET) for fibers, films, container plastics and specialty plastic applications.

[0005] The largest polyester segment is the textile market, where it is used to make clothing, household textiles such as sheets and curtains, carpets and rugs, and industrial products such as tire cords, seat belts, hoses and ropes. PET films are used in electrical applications such as dielectric metal foil capacitors, and for food packaging.

[0006] Growth in polyester has not translated into demand for DMT. For most grades of polyester used in textiles and food and beverage packaging, it is more economical to use purified terephthalic acid rather than DMT. Summary of the Invention

[0007] Disclosed herein is a process for converting a polyester selected from the group consisting of polyethylene terephthalate and poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) to a terephthalate of formula (I):

[0008] [ka] Here, R 1 and R 2 is hydrogen, C 1 -C 6 Alkyl, C 1 -C 6 Haloalkyl, C 1 -C 6 Hydroxyalkyl, optionally substituted C 3 -C 8 Cycloalkyl, optionally substituted (C 1 -C 6 Alkyl)(C 3 -C 8 cycloalkyl), optionally substituted aryl, and optionally substituted (C 1 -C 6 R is independently selected from the group consisting of alkyl, aryl, 1 or R 2 is defined as not being hydrogen; and the process includes blending a polyester in a mixture containing: (a) a solvent for swelling the polyester; (b) an alcohol-based solvent; and (c) Substoichiometric Alkoxides

[0009] In one embodiment of the process, R 1 or R 2is methyl.

[0010] In certain embodiments of the process, the alcoholic solvent is selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combination thereof.

[0011] In one embodiment of the process, the alcoholic solvent is methanol.

[0012] In certain embodiments of the process, the solvent for swelling the polyester is selected from the group consisting of non-polar solvents, polar aprotic solvents, polar protic solvents, and any combination thereof.

[0013] In certain embodiments of the process, the solvent for swelling the polyester is selected from the group consisting of DMSO, DMF, acetone, halogenated solvents, n-hexane, nitrobenzene, methanol, benzyl alcohol, benzaldehyde, and any combination thereof.

[0014] In one embodiment of the process, the solvent for swelling the polyester is a halogenated solvent.

[0015] In one embodiment of the process, the solvent for swelling the polyester is methanol.

[0016] In one embodiment of the process, the ratio of the solvent for swelling the polyester to the alcohol-based solvent is between about 0.1:1 and about 2:1 (w:w).

[0017] In one embodiment of the process, the ratio of the solvent for swelling the polyester to the alcohol-based solvent is between about 0.5:1 and about 1:1 (w:w).

[0018] In certain embodiments of the process, the alkoxide is selected from the group consisting of alkali metal alkoxides, alkaline earth metal alkoxides, metal alkoxides, ammonium alkoxides, and any combination thereof.

[0019] In certain embodiments of the process, the alkoxide is selected from the group consisting of sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, and tetrabutylammonium methoxide.

[0020] In one embodiment of the process, the alkoxide is sodium methoxide.

[0021] In certain embodiments of the process, the alkoxide is generated in situ by adding an alkali metal, alkaline earth metal, or metal to an alcohol-based solvent.

[0022] In one embodiment of the process, the ratio of polyester to alkoxide is between about 15:1 and about 125:1 (w:w).

[0023] In one embodiment of the process, the ratio of polyester to alkoxide is between about 20:1 and about 25:1 (w:w).

[0024] In one embodiment of the process, the ratio of polyester to alkoxide is between about 15:1 and about 60:1 (w:w).

[0025] In one embodiment of the process, the ratio of polyester to alkoxide is between about 20:1 and about 50:1 (w:w).

[0026] In certain embodiments of the process, the process is carried out until about an 80% yield of the terephthalate of Formula (I) is achieved.

[0027] In some embodiments of the process, the process is carried out without external heat.

[0028] In certain embodiments of the process, the process is carried out at a temperature between about 25°C and about 85°C.

[0029] In certain embodiments of the process, the process is carried out at a temperature between about 25°C and about 80°C.

[0030] In certain embodiments of the process, the process is carried out at atmospheric pressure.

[0031] In one embodiment of the process, the polyester is polyethylene terephthalate.

[0032] In some embodiments of the process, the process further comprises recovering monoethylene glycol (MEG).

[0033] In one embodiment of the process, the polyester is in the form of polymer flakes and is part of the feed material.

[0034] In one embodiment of the process, the average polymer flake particle size is between 1 mm and 20 mm.

[0035] In one embodiment of the process, the average polymer flake particle size is between 1 mm and 5 mm.

[0036] Also disclosed herein is a process for converting polyethylene terephthalate to dimethyl terephthalate, comprising combining polyethylene terephthalate with a mixture comprising: (a) a solvent for swelling polyethylene terephthalate; (b) methanol; and (c) Substoichiometric amounts of alkoxides.

[0037] In certain embodiments of the process, the solvent for swelling the polyethylene terephthalate is selected from the group consisting of halogenated solvents, DMSO, benzyl alcohol, methanol, and any combination thereof.

[0038] In one embodiment of the process, the solvent for swelling the polyethylene terephthalate is a halogenated solvent.

[0039] In one embodiment of the process, the solvent for swelling the polyethylene terephthalate is methanol.

[0040] In one embodiment of the process, the ratio of polyethylene terephthalate to alkoxide is between about 20:1 and about 25:1 (w:w).

[0041] In one embodiment of the process, the ratio of polyester to alkoxide is between about 15:1 and about 60:1 (w:w).

[0042] In one embodiment of the process, the ratio of polyester to alkoxide is between about 20:1 and about 50:1 (w:w).

[0043] In certain embodiments of the process, the alkoxide is selected from the group consisting of sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, and tetrabutylammonium methoxide.

[0044] In one embodiment of the process, the alkoxide is sodium methoxide.

[0045] In one embodiment of the process, the ratio of solvent to methanol for swelling the polyethylene terephthalate is between about 0.5:1 and about 1:1 (w:w).

[0046] In one embodiment of the process, the process is carried out until about an 80% yield of dimethyl terephthalate is achieved.

[0047] In some embodiments of the process, the process is carried out without external heat.

[0048] In certain embodiments of the process, the process is carried out at a temperature between about 25°C and about 85°C.

[0049] In certain embodiments of the process, the process is carried out at a temperature between about 25°C and about 80°C.

[0050] In certain embodiments of the process, the process is carried out at atmospheric pressure.

[0051] In some embodiments of the process, the process further comprises recovering monoethylene glycol (MEG).

[0052] In one embodiment of the process, the polyethylene terephthalate is in the form of polymer flakes and is part of the feed material.

[0053] In one embodiment of the process, the average polymer flake particle size is between 1 mm and 20 mm.

[0054] In one embodiment of the process, the average polymer flake particle size is between 1 mm and 5 mm.

[0055] Also provided herein is dimethyl terephthalate (DMT) prepared using the processes described herein.

[0056] Also provided herein is monoethylene glycol (MEG) prepared using the processes described herein.

[0057] Also provided herein is a reaction mixture comprising: (a) a polyester selected from polyethylene terephthalate and poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate); (b) a solvent for swelling the polyester; (c) alcohol-based solvents; and (d) Substoichiometric amounts of alkoxides.

[0058] In certain embodiments of the reaction mixture, the alcoholic solvent is selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combination thereof.

[0059] In certain embodiments of the reaction mixture, the solvent for swelling the polyester is selected from the group consisting of non-polar solvents, polar aprotic solvents, polar protic solvents, and any combination thereof.

[0060] In certain embodiments of the reaction mixture, the solvent for swelling the polyester is a halogenated solvent.

[0061] In one embodiment of the reaction mixture, the solvent for swelling the polyester is methanol.

[0062] In certain embodiments of the reaction mixture, the alcoholic solvent is methanol.

[0063] In certain embodiments of the reaction mixture, the ratio of the solvent for swelling the polyester to the alcoholic solvent is between about 0.5:1 and about 1:1 (w:w).

[0064] In certain embodiments of the reaction mixture, the ratio of polyester to alkoxide is between about 15:1 and about 30:1 (w:w).

[0065] In certain embodiments of the reaction mixture, the ratio of polyethylene terephthalate to alkoxide is between about 20:1 and about 25:1 (w:w).

[0066] In certain embodiments of the reaction mixture, the ratio of polyester to alkoxide is between about 15:1 and about 60:1 (w:w).

[0067] In certain embodiments of the reaction mixture, the ratio of polyester to alkoxide is between about 20:1 and about 50:1 (w:w).

[0068] In certain embodiments of the reaction mixture, the alkoxide is selected from the group consisting of sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, and tetrabutylammonium methoxide.

[0069] In certain embodiments of the reaction mixture, the alkoxide is sodium methoxide.

[0070] In one embodiment of the reaction mixture, the polyester is polyethylene terephthalate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0071] Dimethyl terephthalate (DMT) is used in the manufacture of polyesters, including polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT). Because DMT is volatile, it is an intermediate in some schemes for the recycling of PET (e.g. from plastic bottles). Hydrogenation of DMT gives the diol 1,4-cyclohexanedimethanol, a useful monomer in the formation of polyester resins.

[0072] DMT has been produced in many ways. The conventional and still commercially valuable method is direct esterification of terephthalic acid. Alternatively, it is prepared from paraxylene via methyl p-toluate by alternating oxidation and methyl esterification steps. The method for producing DMT from paraxylene and methanol consists of four main steps: oxidation, esterification, distillation, and crystallization. A mixture of paraxylene and p-toluate esters is oxidized with air in the presence of a transition metal catalyst (Co / Mn). The mixture of acids resulting from the oxidation is esterified with methanol to produce a mixture of esters. The crude ester mixture is distilled to remove any heavy boilers and residues formed; the lighter esters are recycled to the oxidation section. The raw DMT is then crystallized to remove DMT isomers, residual acids, and aromatic aldehydes.

[0073] Improvements in DMT Production from PET Recycle: Due to the increasing use of PET and PETG in the packaging and textile (carpet and other textile) industries, efficient, low-energy, high-yield, and cost-effective methods of forming DMT from PET or PETG are required.

[0074] polyester Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcohol-based solvent; and (c) Substoichiometric amounts of alkoxides.

[0075] In some embodiments, the polyester is selected from polyethylene terephthalate (PET), poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG), polyglycolide or polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxybutyrate (PHB), polyethylene adipate (PEA), polybutylene succinate (PBS), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), Vectran®, cutin, and any combination thereof.

[0076] In some embodiments, the polyester is polyethylene terephthalate (PET):

[0077] [ka]

[0078] In some embodiments, the polyester is a terephthalic acid / ethylene glycol oligomer.

[0079] In some embodiments, the polyester is poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate (PETG):

[0080] [ka]

[0081] In some embodiments, the polyester is polyglycolide or polyglycolic acid (PGA).

[0082] [ka]

[0083] In some embodiments, the polyester is polylactic acid (PLA):

[0084] [ka]

[0085] In some embodiments, the polyester is polycaprolactone (PCL):

[0086] [ka]

[0087] In some embodiments, the polyester is polyhydroxybutyrate (PHB):

[0088] [ka]

[0089] In some embodiments, the polyester is polyethylene adipate (PEA):

[0090] [ka]

[0091] In some embodiments, the polyester is polybutylene succinate (PBS):

[0092] [ka]

[0093] In some embodiments, the polyester is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV):

[0094] [ka]

[0095] In some embodiments, the polyester is polybutylene terephthalate (PBT):

[0096] [ka]

[0097] In some embodiments, the polyester is polytrimethylene terephthalate (PTT):

[0098] [ka]

[0099] In some embodiments, the polyester is polyethylene naphthalate (PEN):

[0100] [ka]

[0101] In some embodiments, the polyester is Vectran®:

[0102] [ka]

[0103] In some embodiments, the polyester is cutin. Cutin is one of two waxy polymers that are the main components of the plant cuticle and cover all aerial surfaces of the plant. Cutin consists of omega hydroxy acids and their derivatives, linked via ester bonds to form polyester polymers. There are two main cutin monomer families, the C16 and C18 families. The C16 family consists mainly of 16-hydroxypalmitic acid and 9,16- or 10,16-dihydroxypalmitic acid. The C18 family consists mainly of 18-hydroxyoleic acid, 9,10-epoxy-18-hydroxystearic acid, and 9,10,18-trihydroxystearate. Tomato cutin consists of 16-hydroxypalmitic acid and 10,16-dihydroxypalmitic acid, where the 10-isomer is generally predominant. Tomato cutin is a transesterified polyester biopolymer. The significant proportion of secondary esters (esterification at the secondary hydroxyl at C-10) indicates that the structure of the polyester is highly branched.

[0104] In some embodiments, the polyester is in a feedstock that includes impurities such as additional polymers (e.g., polyethylene, polypropylene, polyvinyl chloride (PVC), paper, colorants, dust, ethylene vinyl alcohol (EvOH), polycarbonate (PC), polyvinylidene chloride (PVDC), ethylene vinyl acetate (EVA), adhesives, polyamides, or any combination thereof). In some embodiments, the feedstock includes between about 5% and about 20% impurities.

[0105] Mishra et al. (Kinetic and thermodynamic study of methanolysis of poly(ethylene terephthalate)waste powder Polym. Int. 52:337-342 (2003)) showed that an increase in particle size of PET flakes causes a decrease in depolymerization. Mishra et al. recorded 127.5 μm as the optimal particle size. There is a demand for a depolymerization process that allows for the use of larger polymer flakes. In some embodiments, the feed material includes polymer flakes. In some embodiments, the average polymer flake particle size is between 1 mm and 20 mm. In some embodiments, the average polymer flake particle size is between 1 mm and 15 mm. In some embodiments, the average flake particle size is between 1 mm and 10 mm. In some embodiments, the average polymer flake particle size is between 1 mm and 5 mm.

[0106] Ester Derivatives Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcohol-based solvent; and (c) Substoichiometric amounts of alkoxides.

[0107] In some embodiments, the polyester is polyglycolide or polyglycolic acid (PGA) and the ester derivative is a 2-hydroxyacetate derivative, hi some embodiments, the ester derivative is methyl 2-hydroxyacetate.

[0108] In some embodiments, the polyester is polylactic acid (PLA) and the ester derivative is a 2-hydroxypropanoate derivative, hi some embodiments, the ester derivative is methyl 2-hydroxypropanoate.

[0109] In some embodiments, the polyester is polycaprolactone (PCL) and the ester derivative is a 6-hydroxyhexanoate derivative, hi some embodiments, the ester derivative is methyl 6-hydroxyhexanoate.

[0110] In some embodiments, the polyester is polyhydroxybutyrate (PHB) and the ester derivative is a hydroxybutyrate derivative, hi some embodiments, the ester derivative is methylhydroxybutyrate.

[0111] In some embodiments, the polyester is polyethylene adipate (PEA) and the ester derivative is an adipate derivative, hi some embodiments, the ester derivative is dimethyl adipate.

[0112] In some embodiments, the polyester is polybutylene succinate (PBS) and the ester derivative is a succinate derivative, hi some embodiments, the ester derivative is dimethyl succinate.

[0113] In some embodiments, the polyester is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and the ester derivative is a hydroxybutyrate derivative, a hydroxyvalerate derivative, or a combination thereof, hi some embodiments, the ester derivative is methyl hydroxybutyrate, methyl hydroxyvalerate, or a combination thereof.

[0114] In some embodiments, the polyester is polyethylene naphthalate (PEN) and the ester derivative is a naphthalate derivative, hi some embodiments, the ester derivative is dimethyl naphthalate.

[0115] In some embodiments, the polyester is vectran and the ester derivative is a naphthoate derivative, a benzoate derivative, or a combination thereof, hi some embodiments, the ester derivative is methyl hydroxynaphthoate or methyl hydroxybenzoate.

[0116] In some embodiments, the polyester is cutin and the ester derivative is a hydroxypalmitate or dihydroxypalmitate derivative, hi some embodiments, the ester derivative is methylhydroxypalmitate or methyldihydroxypalmitate.

[0117] In some embodiments, the polyester is polyethylene terephthalate (PET), poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG), polytrimethylene terephthalate (PTT), or polybutylene terephthalate (PBT), and the ester derivative is a terephthalate derivative. In some embodiments, the terephthalate derivative is a compound of formula (I):

[0118] [ka] In the formula, R 1 and R 2 is hydrogen, C 1 -C 6 Alkyl, C 1 -C 6 Haloalkyl, C 1 -C 6 Hydroxyalkyl, optionally substituted C 3 -C 8 Cycloalkyl, optionally substituted (C 1 -C 6 Alkyl)(C 3 -C 8 cycloalkyl), optionally substituted aryl, and optionally substituted (C 1 -C 6R is independently selected from the group consisting of alkyl, aryl, 1 or R 2 One of them is not hydrogen.

[0119] In some embodiments of the compounds of Formula (I), R 1 and R 2 is independently C 1 -C 6 Alkyl or C 1 -C 6 It is a hydroxyalkyl.

[0120] In some embodiments of the compounds of Formula (I), R 1 and R 2 is independently C 1 -C 6 In some embodiments of the compounds of formula (I), R 1 and R 2 is independently methyl, ethyl, propyl, isopropyl, or butyl. In some embodiments of the compound of Formula (I), R 1 and R 2 is independently methyl or ethyl. In some embodiments of the compounds of Formula (I), R 1 and R 2 is methyl. In some embodiments of the compounds of Formula (I), R 1 and R 2 is ethyl. In some embodiments of the compounds of Formula (I), R 1 and R 2 is not hydrogen.

[0121] In some embodiments of the compounds of Formula (I), R 1 and R 2 is independently C 1 -C 6 In some embodiments of the compounds of formula (I), R 1 and R 2 is independently hydroxyethyl or propanediol. In some embodiments of the compounds of Formula (I), R 1 and R2 is hydroxyethyl. In some embodiments of the compounds of Formula (I), R 1 and R 2 is 2-hydroxyethyl. In some embodiments of the compounds of Formula (I), R 1 and R 2 is dihydroxypropyl. In some embodiments of the compounds of Formula (I), R 1 and R 2 is 2,3-dihydroxypropyl.

[0122] In some embodiments of the compounds of Formula (I), R 1 and R 2 are independently optionally substituted (C 1 -C 6 Alkyl)(C 3 -C 8 In some embodiments of the compounds of formula (I), R 1 and R 2 were independently substituted (C 1 -C 6 Alkyl)(C 3 -C 8 In some embodiments of the compounds of formula (I), R 1 and R 2 is 4-(hydroxymethyl)cyclohexyl)methyl.

[0123] In some embodiments of the compounds of Formula (I), R 1 and R 2 is independently an optionally substituted aryl. In some embodiments of the compounds of Formula (I), R 1 and R 2 is phenyl.

[0124] In some embodiments of the compounds of Formula (I), R 1 and R 2 are independently optionally substituted (C 1 -C 6 In some embodiments of the compounds of formula (I), R1 and R 2 is benzyl.

[0125] In some embodiments, the ester derivatives contain less than about 10% impurities (w / w). In some embodiments, the ester derivatives contain less than about 9% impurities (w / w). In some embodiments, the ester derivatives contain less than about 8% impurities (w / w). In some embodiments, the ester derivatives contain less than about 7% impurities (w / w). In some embodiments, the ester derivatives contain less than about 6% impurities (w / w). In some embodiments, the ester derivatives contain less than about 5% impurities (w / w). In some embodiments, the ester derivatives contain less than about 4% impurities (w / w). In some embodiments, the ester derivatives contain less than about 3% impurities (w / w). In some embodiments, the ester derivatives contain less than about 2% impurities (w / w). In some embodiments, the ester derivatives contain less than about 1% impurities (w / w). In some embodiments, the ester derivatives contain less than about 0.5% impurities (w / w). In some embodiments, the ester derivatives contain less than about 0.4% impurities (w / w). In some embodiments, the ester derivatives contain less than about 0.3% impurities (w / w). In some embodiments, the ester derivatives contain less than about 0.2% impurities (w / w).In some embodiments, the ester derivatives contain less than about 0.1% impurities (w / w).

[0126] In some embodiments, the ester derivatives are at less than about 250 ppm of any metal, less than about 240 ppm of any metal, less than about 230 ppm of any metal, less than about 220 ppm of any metal, less than about 210 ppm of any metal, less than about 200 ppm of any metal, less than about 190 ppm of any metal, less than about 180 ppm of any metal, less than about 170 ppm of any metal, less than about 160 ppm of any metal, less than about 150 ppm of any metal, less than about 140 ppm of any metal, less than about 130 ppm of any metal, less than about 120 ppm of any metal, less than about 110 ppm of any metal, less than about 100 ppm of any metal, less than about 90 ppm of any metal, less than about 80 ppm of any metal, less than about 70 ppm of any metal, less than about 60 ppm of any metal, less than about 50 ppm of any metal, less than about 40 ppm of any metal, less than about 30 ppm of any metal, less than about 20 ppm of any metal, any metal, less than about 10 ppm of any metal, less than about 5 ppm of any metal, less than about 4 ppm of any metal, less than about 3 ppm of any metal, less than about 2 ppm of any metal, less than about 1 ppm of any metal, less than about 0.9 ppm of any metal, less than about 0.8 ppm of any metal, less than about 0.7 ppm of any metal, less than about 0.6 ppm of any metal, less than about 0.5 ppm of any metal, less than about 0.4 ppm of any metal, less than about 0.3 ppm of any metal any metal, less than about 0.2 ppm of any metal, less than about 0.1 ppm of any metal, less than about 0.09 ppm of any metal, less than about 0.08 ppm of any metal, less than about 0.07 ppm of any metal, less than about 0.06 ppm of any metal, less than about 0.05 ppm of any metal, less than about 0.04 ppm of any metal, less than about 0.03 ppm of any metal, less than about 0.02 ppm of any metal, or less than about 0.01 ppm of any metal.

[0127] Glycol Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcohol-based solvent; and (c) Substoichiometric amounts of alkoxides.

[0128] In some embodiments, the process further comprises forming a glycol. In some embodiments, the glycol is monoethylene glycol (MEG) (or ethylene glycol). In some embodiments, the glycol is propylene glycol. In some embodiments, the glycol is butylene glycol.

[0129] In some embodiments, the glycol is obtained in a yield of between about 80 and about 99 mol%. In some embodiments, the glycol is obtained in a yield of between about 85 and about 99 mol%. In some embodiments, the glycol is obtained in a yield of between about 90 and about 99 mol%. In some embodiments, the glycol is obtained in a yield of at least about 80 mol%. In some embodiments, the glycol is obtained in a yield of at least about 85 mol%.

[0130] In some embodiments, the glycol contains less than about 10% impurities (w / w). In some embodiments, the glycol contains less than about 9% impurities (w / w). In some embodiments, the glycol contains less than about 8% impurities (w / w). In some embodiments, the glycol contains less than about 7% impurities (w / w). In some embodiments, the glycol contains less than about 6% impurities (w / w). In some embodiments, the glycol contains less than about 5% impurities (w / w). In some embodiments, the glycol contains less than about 4% impurities (w / w). In some embodiments, the glycol contains less than about 3% impurities (w / w). In some embodiments, the glycol contains less than about 2% impurities (w / w). In some embodiments, the glycol contains less than about 1% impurities (w / w). In some embodiments, the glycol contains less than about 0.5% impurities (w / w). In some embodiments, the glycol contains less than about 0.4% impurities (w / w). In some embodiments, the glycol contains less than about 0.3% impurities (w / w). In some embodiments, the glycol contains less than about 0.2% impurities (w / w). In some embodiments, the glycol contains less than about 0.1% impurities (w / w).

[0131] In some embodiments, the glycol is less than about 250 ppm of any metal, less than about 240 ppm of any metal, less than about 230 ppm of any metal, less than about 220 ppm of any metal, less than about 210 ppm of any metal, less than about 200 ppm of any metal, less than about 190 ppm of any metal, less than about 180 ppm of any metal, less than about 170 ppm of any metal, less than about 160 ppm of any metal, less than about 150 ppm of any metal, less than about 140 ppm of any metal, less than about 130 ppm of any metal, less than about 120 ppm of any metal, less than about 110 ppm of any metal, less than about 100 ppm of any metal, less than about 90 ppm of any metal, less than about 80 ppm of any metal, less than about 70 ppm of any metal, less than about 60 ppm of any metal, less than about 50 ppm of any metal, less than about 40 ppm of any metal, less than about 30 ppm of any metal, less than about 20 ppm of any metal, metal, less than about 10 ppm of any metal, less than about 5 ppm of any metal, less than about 4 ppm of any metal, less than about 3 ppm of any metal, less than about 2 ppm of any metal, less than about 1 ppm of any metal, less than about 0.9 ppm of any metal, less than about 0.8 ppm of any metal, less than about 0.7 ppm of any metal, less than about 0.6 ppm of any metal, less than about 0.5 ppm of any metal, less than about 0.4 ppm of any metal, less than about 0.3 ppm of any metal, less than about 0.2 ppm of any metal, less than about 0.1 ppm of any metal, less than about 0.09 ppm of any metal, less than about 0.08 ppm of any metal, less than about 0.07 ppm of any metal, less than about 0.06 ppm of any metal, less than about 0.05 ppm of any metal, less than about 0.04 ppm of any metal, less than about 0.03 ppm of any metal, less than about 0.02 ppm of any metal, or less than about 0.01 ppm of any metal.

[0132] Alcohol-based solvents Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcohol-based solvent; and (c) Substoichiometric amounts of alkoxides.

[0133] In some embodiments, the processes described herein include an alcoholic solvent. In some embodiments, the alcoholic solvent is a straight chain alcohol, a branched alcohol, a cyclic alcohol, or any combination thereof. In some embodiments, the alcoholic solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combination thereof.

[0134] In some embodiments, the alcohol solvent is a linear C 1 -C 4 In some embodiments, the alcoholic solvent is methanol, ethanol, propanol, butanol, or a combination thereof. In some embodiments, the alcoholic solvent is methanol, ethanol, propanol, or a combination thereof. In some embodiments, the alcoholic solvent is methanol. In some embodiments, the alcohol is ethanol. In some embodiments, the alcoholic solvent is a branched C 3 -C 4 In some embodiments, the alcohol is t-butanol, s-butanol, i-butanol, i-propanol, or any combination thereof. In some embodiments, the alcohol solvent is a cyclic C 3 -C 8In some embodiments, the alcoholic solvent is cyclopropanol, cyclobutanol, cyclopentanol, cyclohexanol, cycloheptanol, cyclohexane-1,4-diyldimethanol, or any combination thereof. In some embodiments, the alcoholic solvent is cyclohexane-1,4-diyldimethanol.

[0135] In some embodiments, the alcohol-based solvent is a polyol, hi some embodiments, the alcohol-based solvent is selected from ethylene glycol, glycerol, and any combination thereof.

[0136] In some embodiments, the alcoholic solvent is selected from phenol, benzyl alcohol, and any combination thereof.

[0137] Solvent for swelling polyester Described herein are processes for converting polyesters to ester derivatives; comprising mixing the polyesters in a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcohol-based solvent; and (c) Substoichiometric amounts of alkoxides.

[0138] In some embodiments, the processes described herein include pretreating the polyester with a solvent for swelling the polyester prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 5 minutes to about 60 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 5 minutes to about 40 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 5 minutes to about 20 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 5 minutes to about 10 minutes prior to the addition of the alcoholic solvent and the alkoxide. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 5 minutes. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 10 minutes. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 15 minutes. In some embodiments, the solvent for swelling the polyester pretreatment is performed for about 20 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 25 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 30 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 35 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 40 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 45 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 50 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 55 minutes. In some embodiments, the solvent pretreatment for swelling the polyester is carried out for about 60 minutes.

[0139] In some embodiments, the processes described herein include pre-treating the polyester with a solvent to swell the polyester simultaneously with the addition of the alcohol-based solvent and the alkoxide.

[0140] In some embodiments, the solvent for swelling the polyester is selected from non-polar solvents, polar aprotic solvents, polar protic solvents, and any combination thereof.

[0141] In some embodiments, the solvent for swelling the polyester is selected from dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), acetone, halogenated solvents, n-hexane, nitrobenzene, methanol, benzyl alcohol, benzaldehyde, and any combination thereof. In some embodiments, the solvent for swelling the polyester is selected from DMSO, halogenated solvents, and any combination thereof. In some embodiments, the solvent for swelling the polyester is DMSO. In some embodiments, the solvent for swelling the polyester is a halogenated solvent. In some embodiments, the solvent for swelling the polyester is a chlorinated solvent. In some embodiments, the solvent for swelling the polyester is dichloromethane, dichloroethane, tetrachloroethane, chloroform, tetrachloromethane, trichloroethane, or any combination thereof. In some embodiments, the solvent for swelling the polyester is dichloromethane. In some embodiments, the solvent for swelling the polyester is methanol.

[0142] In some embodiments, the ratio of the solvent for swelling the polyester to the alcohol-based solvent is between about 0.1:1 and about 2:1 (w:w).In some embodiments, the ratio of the solvent for swelling the polyester to the alcohol-based solvent is between about 1:1 and about 2:1 (w:w). In some embodiments, the ratio of the solvent for swelling the polyester to the alcohol-based solvent is between about 0.1:1 and about 2:1 (w:w), or between about 0.2:1 and about 2:1 (w:w), or between about 0.3:1 and about 2:1 (w:w), or between about 0.4:1 and about 2:1 (w:w), or between about 0.5:1 and about 2:1 (w:w), or between about 0.6:1 and about 2:1 (w:w), or between about 0.7:1 and about 2:1 (w:w), or between about 0.8:1 and about 2:1 (w:w), or between about 0.9:1 and about 2:1 (w:w), or between about 1:1 and about 2:1 (w:w). or between about 1:2 and about 2:1 (w:w), or between about 1:3 and about 2:1 (w:w), or between about 1:4 and about 2:1 (w:w), or between about 1:4 and about 2:1 (w:w), or between about 1:6 and about 2:1 (w:w), or between about 1:7 and about 2:1 (w:w), or between about 1:8 and about 2:1 (w:w), or between about 1:9 and about 2:1 (w:w), or between about 0.5:1 and about 1.5:1 (w:w), or between about 0.5:1 and about 1.5:1 (w:w), or between about 0.5:1 and about 1.5:1 (w:w), or between about 1:1 and about 1.5:1 (w:w). In some embodiments, the ratio of solvent for swelling the polyester to the alcohol-based solvent is between about 0.5:1 and about 1:1 (w:w).

[0143] Alkoxide Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcoholic solvent; and (c) Substoichiometric amounts of alkoxides.

[0144] In some embodiments, the processes described herein include adding a substoichiometric amount of an alkoxide. In some embodiments, the processes described herein include adding a catalytic amount of an alkoxide.

[0145] As used herein, the term "substoichiometric amount" is used to indicate that the amount of material used is less than the stoichiometric amount. The term is used interchangeably herein with "catalytic amount." In some embodiments, the substoichiometric amount is about 95% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 90% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 85% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 80% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 75% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 70% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 65% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 60% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 55% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 50% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 45% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 40% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 35% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 30% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 25% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 20% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 15% or less of the stoichiometric amount. In some embodiments, the substoichiometric amount is about 10% or less of the stoichiometric amount.

[0146] "Stoichiometric amount," as used herein, is used to indicate that the amount of material used is equivalent to the number of ester bonds present in the polyester.

[0147] In some embodiments, the alkoxide comprising an alkoxide anion and a cation is selected from an alkali metal alkoxide, an alkaline earth metal alkoxide, a metal alkoxide, an ammonium alkoxide, and any combination thereof. In some embodiments, the alkoxide anion is C 1 -C 4 An alkoxide anion. In some embodiments, the alkoxide anion is selected from methoxide, ethoxide, n-propoxide, n-butoxide, t-butoxide, sec-butoxide, iso-butoxide, iso-propoxide, and combinations thereof. In some embodiments, the alkoxide anion is methoxide, ethoxide, or any combination thereof. In some embodiments, the alkoxide anion is methoxide. In some embodiments, the cation is lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, or ammonium. In some embodiments, the alkoxide is sodium methoxide, potassium ethoxide, or aluminum tri-n-propoxide. In some embodiments, the ammonium alkoxide is a tetraalkylammonium alkoxide. In some embodiments, the ammonium alkoxide is tetrabutylammonium alkoxide. In some embodiments, the alkoxide is sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, or tetrabutylammonium methoxide.

[0148] In some embodiments, the alkoxide is generated in situ by adding an alkali metal, alkaline earth metal, or metal to an alcohol-based solvent.

[0149] In some embodiments, the ratio of polyester to alkoxide is between about 15:1 and about 125:1 (w:w), or between about 15:1 and about 100:1 (w:w), or between about 15:1 and about 80:1 (w:w), or between about 15:1 and about 60:1 (w:w), or between about 15:1 and about 40:1 (w:w), or between about 15:1 and about 25:1 (w:w), or between about 15:1 and about 20:1 (w:w), or between about 20:1 and about 25:1 (w:w), or between about 20:1 and about 50:1 (w:w). The ratio of polyester to alkoxide is between about 0:1 (w:w), between about 30:1 and about 60:1 (w:w), between about 40:1 and about 70:1 (w:w), between about 50:1 and about 80:1 (w:w), between about 60:1 and about 90:1 (w:w), between about 20:1 and about 125:1 (w:w), between about 40:1 and about 125:1 (w:w), between about 60:1 and about 125:1 (w:w), between about 80:1 and about 125:1 (w:w), or between about 100:1 and about 125:1 (w:w). In some embodiments, the ratio of polyester to alkoxide is between about 20:1 and about 25:1 (w:w).

[0150] Reaction time Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcoholic solvent; and (c) Substoichiometric amounts of alkoxides.

[0151] In some embodiments, the polyester is mixed with the solvent, alkoxide, and alcohol-based solvent for swelling the polyester for a sufficient time. In some embodiments, the polyester is mixed with the solvent, alkoxide, and alcohol-based solvent for swelling the polyester until about 70% yield of the desired ester is reached. In some embodiments, the polyester is mixed with the solvent, alkoxide, and alcohol-based solvent for swelling the polyester until about 75% yield of the desired ester is reached. In some embodiments, the polyester is mixed with the solvent, alkoxide, and alcohol-based solvent for swelling the polyester until about 80% yield of the desired ester is reached. In some embodiments, the polyester is mixed with the solvent, alkoxide, and alcohol-based solvent for swelling the polyester until about 85% yield of the desired ester is reached. In some embodiments, the polyester is mixed with the solvent, alkoxide, and alcohol-based solvent for swelling the polyester until about 90% yield of the desired ester is reached. In some embodiments, mixing the polyester with a solvent for swelling the polyester, an alkoxide, and an alcohol-based solvent is carried out until about a 95% yield of the desired ester is reached.

[0152] In some embodiments, mixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcohol-based solvent is carried out for about 10 minutes to 5 hours, or about 10 minutes to 4 hours, or about 10 minutes to 3 hours, or about 10 minutes to 2 hours, or about 20 minutes to 2 hours, or about 30 minutes to 2 hours, or about 40 minutes to 2 hours, or about 30 minutes to 1 hour, or about 30 minutes to 1.5 hours. In some embodiments, the polyester is mixed with the solvent for swelling the polyester, the alkoxide, and the alcohol-based solvent for about 10 minutes, or about 15 minutes, or about 20 minutes, or about 25 minutes, or about 30 minutes, or about 35 minutes, or about 40 minutes, or about 45 minutes, or about 50 minutes, or about 60 minutes, or about 70 minutes, or about 80 minutes, or about 90 minutes, or about 100 minutes, or about 110 minutes, or about 120 minutes, or about 130 minutes, or about 140 minutes, or about 150 minutes, or about 160 minutes, or about 170 minutes, or about 180 minutes. In some embodiments, the polyester is mixed with the solvent for swelling the polyester, the alkoxide, and the alcohol-based solvent for about 1 hour, or about 2 hours, or about 3 hours, or about 4 hours, or about 5 hours.

[0153] temperature Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcoholic solvent; and (c) Substoichiometric amounts of alkoxides.

[0154] In some embodiments, the processes disclosed herein are carried out at ambient temperature. In some embodiments, the ambient temperature is 25±5° C.

[0155] In some embodiments, the processes disclosed herein are carried out without external heat. In some embodiments, the process is exothermic and the temperature of the reaction mixture is increased to at least 30° C., at least 35° C., at least 40° C., at least 45° C., at least 50° C., at least 55° C., or at least 60° C. In some embodiments, no external heat source is used to increase the temperature of the reaction mixture.

[0156] In some embodiments, the processes disclosed herein are carried out with external heat. In some embodiments, the processes disclosed herein are carried out with external heat at about 25°C to about 100°C, about 25°C to about 85°C, or about 25°C to about 80°C, or about 25°C to about 60°C, about 40°C to about 60°C, or about 40°C to about 50°C, or about 30°C to about 50°C. In some embodiments, the processes disclosed herein are carried out at about 26°C, about 27°C, about 28°C, about 29°C, about 30°C, about 31°C, about 32°C, about 33°C, about 34°C, about 35°C, about 36°C, about 37°C, about 38°C, about 39°C, about 40°C, about 41°C, about 42°C, about 43°C, about 44°C, about 45°C, about 46°C, about 47°C, about 48°C, about 49°C, about 50°C, about 51°C, about 52°C, about 53°C, about 54°C, about 55°C, about 56°C, about 57°C, about 58°C, about 59°C, about 60°C, about 61°C, about 62°C, about 63°C, about 64°C, about 65°C, about 66°C, about 67°C, about 68°C, about 69°C, about 70°C, about 71°C, about 72°C, about 73°C, about 74°C, about 75°C, about 76°C, about 77°C, about 78°C, about 79°C, about 80°C, about 81°C, about 82°C, about 83°C, about 84°C, about 85°C, about 86°C, about 87°C, about 88°C, about 89°C, about 90°C, about 91°C, about 92°C, about 93°C, about 94°C, about 95°C, about 96°C, about The reaction may be carried out at about 1°C, about 62°C, about 63°C, about 64°C, about 65°C, about 66°C, about 67°C, about 68°C, about 69°C, about 70°C, about 71°C, about 72°C, about 73°C, about 74°C, about 75°C, about 76°C, about 77°C, about 78°C, about 79°C, about 80°C, about 81°C, about 82°C, about 83°C, about 84°C, about 85°C, about 86°C, about 87°C, about 88°C, about 89°C, about 90°C, about 91°C, about 92°C, about 93°C, about 94°C, about 95°C, about 96°C, about 97°C, about 98°C, about 99°C, or about 100°C.

[0157] pressure In some embodiments, the processes disclosed herein are carried out at atmospheric pressure. In some embodiments, the processes disclosed herein are carried out at elevated pressure. In some embodiments, the processes disclosed herein are carried out at pressures between about atmospheric pressure and about 220 psi, or between about atmospheric pressure and about 200 psi, or between about atmospheric pressure and about 150 psi, or between about atmospheric pressure and about 100 psi, or between about atmospheric pressure and about 50, or between about 20 psi and about 150 psi, or between about 50 and about 100 psi. In some embodiments, the processes disclosed herein are conducted at about 14 psi, about 15 psi, about 16 psi, about 17 psi, about 18 psi, about 19 psi, about 20 psi, about 30 psi, about 40 psi, about 50 psi, about 60 psi, about 70 psi, about 80 psi, about 90 psi, about 100 psi, about 110 psi, about 120 psi, about 130 psi, about 140 psi, about 150 psi, about 160 psi, about 170 psi, about 180 psi, about 190 psi, about 200 psi, about 210 psi, or about 220 psi.

[0158] stirring Described herein is a process for converting polyesters to ester derivatives; comprising combining the polyesters with a mixture comprising: (a) a solvent for swelling the polyester; (b) an alcoholic solvent; and (c) Substoichiometric amounts of alkoxides.

[0159] In some embodiments, the processes disclosed herein are carried out without stirring. In some embodiments, the processes disclosed herein are carried out with enhanced stirring. In some embodiments, a stirred batch reactor is used to provide the stirring. In some embodiments, a continuous reactor is used to provide the stirring.

[0160] Specific Terms The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0161] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood to belong to the subject matter of the claims. In the event that there are multiple definitions for terms herein, the definition in this section shall prevail. It will be understood that the general description and the detailed description are exemplary and explanatory only, and are not intended to be limiting in any respect. In this application, the use of the singular encompasses the plural unless expressly stated otherwise. It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" encompass plural referents unless the content clearly dictates otherwise. In this application, the use of "or" means "and / or" unless expressly stated otherwise. Additionally, the use of the term "including" is open-ended, as are other forms such as "include," "includes," and "included."

[0162] Unless otherwise required by context, throughout this specification and the claims which follow, the terms "comprise" and variations thereof, such as "comprises" and "comprising," are to be construed in their open, inclusive sense, i.e., "including but not limited to." Moreover, the headings provided herein are for convenience only and do not interpret the scope or meaning of the invention as claimed.

[0163] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless expressly stated otherwise. It should also be noted that the term "or" is generally utilized in its sense including "and / or" unless the context clearly dictates otherwise.

[0164] As used herein, the term "about" or "approximately" means within 10%, preferably within 10%, and more preferably within 5% of a given value or range.

[0165] As used herein, ambient temperature is a colloquial expression for a typical or preferred indoor (air-conditioned) temperature, the temperature to which people are generally accustomed. It represents a small range of approximately 21°C, the temperature of air that does not feel hot or cold. In some embodiments, the ambient temperature is 25±5°C. In some embodiments, the ambient temperature is 18°C. In some embodiments, the ambient temperature is 19°C. In some embodiments, the ambient temperature is 20°C. In some embodiments, the ambient temperature is 21°C. In some embodiments, the ambient temperature is 22°C. In some embodiments, the ambient temperature is 23°C. In some embodiments, the ambient temperature is 24°C. In some embodiments, the ambient temperature is 25°C. In some embodiments, the ambient temperature is 26°C. In some embodiments, the ambient temperature is 27°C. In some embodiments, the ambient temperature is 28°C. In some embodiments, the ambient temperature is 29°C. In some embodiments, the ambient temperature is 30°C.

[0166] As used herein and in the appended claims, depolymerization refers to a process that breaks down a polymer into its starting materials. Depolymerization is essentially the opposite of polymerization. In some embodiments, depolymerization is accomplished by glycolysis, methanolysis, or hydrolysis, which are classified according to the depolymerization reactants used, such as glycol, methanol, or water, respectively.

[0167] Definitions of standard chemistry terms may be found in reference sources, including, but not limited to, Carey and Sundberg "ADVANCED ORGANIC CHEMISTRY 4TH ED" Vols. A (2000)and B (2001), Plenum Press, New York.

[0168] As used herein, the following terms have the following meanings unless otherwise specified.

[0169] "Alkyl" refers to a straight or branched hydrocarbon chain radical attached to another part of the molecule by a single bond. For example, a straight chain alkyl containing up to four carbon atoms is a straight chain C 1 -C 4 Similarly, straight-chain alkyls containing up to three carbon atoms are called straight-chain C 1 -C 3 A straight chain alkyl is a straight chain C 1 -C 4 Alkyl, linear C 1 -C 3 Alkyl, linear C 1 -C 2 Alkyl, linear C 2 -C 3 Alkyl and linear C 2 -C 4 Representative alkyls include methyl, ethyl, propyl, and butyl. Branched alkyls containing 3 and 4 carbon atoms are referred to as branched C 3 -C 4 Representative branched alkyl groups include, but are not limited to, t-butyl, sec-butyl, isobutyl, and isopropyl. Unless otherwise specifically stated in the specification, alkyl is not limited to oxygen, halogen, -CN, -CF 3 , OH, -OMe, NH 2 , or -NO 2 In some embodiments, alkyl is optionally substituted with oxygen, halogen, -CN, -CF 3, OH, or -OMe. In some embodiments, the alkyl is optionally substituted with halogen.

[0170] "Halo" or "halogen" refers to bromo, chloro, fluoro, or iodo. In some embodiments, the halogen is fluoro or chloro. In some embodiments, the halogen is fluoro.

[0171] "Haloalkyl" refers to an alkyl radical as defined above substituted with one or more halo atoms as defined above, for example, trifluoromethyl, difluoromethyl, fluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl, 1,2-difluoroethyl, 3-bromo-2-fluoropropyl, 1,2-dibromoethyl, and the like.

[0172] As defined above, "hydroxyalkyl" refers to an alkyl radical that is substituted with one or more --OH groups, such as hydroxymethyl, hydroxyethyl, hydroxypropyl, propanediol, and the like.

[0173] "Cycloalkyl" refers to a stable, partially or fully saturated, monocyclic or polycyclic carbocyclic ring, which may contain fused or bridged ring systems. Representative cycloalkyls are those containing 3 to 15 carbon atoms (C 3 -C 1 5 cycloalkyl), 3 to 10 carbon atoms (C 3 -C 1 0 cycloalkyl), 3 to 8 carbon atoms (C 3 -C 8 Cycloalkyl), 3 to 6 carbon atoms (C 3 -C 6 Cycloalkyl), 3 to 5 carbon atoms (C 3 -C 5 cycloalkyl), or 3-4 carbon atoms (C 3 -C 4In some embodiments, the cycloalkyl is a 3- to 6-membered cycloalkyl. In some embodiments, the cycloalkyl is a 5- to 6-membered cycloalkyl. Monocyclic cycloalkyls include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Polycyclic cycloalkyls or carbocycles include, for example, adamantyl, norbornyl, decalinyl, bicyclo[3.3.0]octane, bicyclo[4.3.0]nonane, cis-decalin, trans-decalin, bicyclo[2.1.1]hexane, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, bicyclo[3.2.2]nonane, and bicyclo[3.3.2]decane, and 7,7-dimethyl-bicyclo[2.2.1]heptanyl. Partially saturated cycloalkyl includes, for example, cyclopentenyl, cyclohexenyl, cycloheptenyl, and cyclooctenyl. Unless specifically stated otherwise in the specification, cycloalkyl includes oxo, halogen, methyl, ethyl, -CN, -CF 3 , OH, -OMe, NH 2 , or -NO 2 In some embodiments, cycloalkyl is optionally substituted with oxo, halogen, methyl, ethyl, -CN, -CF 3 , OH, or -OMe. In some embodiments, cycloalkyl is optionally substituted with halogen.

[0174] "Aryl" refers to a radical derived from a hydrocarbon ring system containing hydrogen, 6-30 carbon atoms, and at least one aromatic ring. The aryl radical may be a monocyclic, bicyclic, tricyclic, or tetracyclic ring system, which may include fused or bridged ring systems. In some embodiments, the aryl is a 6-10 membered aryl. In some embodiments, the aryl is a 6 membered aryl. Aryl radicals include, but are not limited to, aryl radicals derived from anthrylene, naphthylene, phenanthrylene, anthracene, azulene, benzene, chrysene, fluoranthene, fluorene, as-indacene, s-indacene, indane, indene, naphthalene, phenalene, phenanthrene, pleiadene, pyrene, and triphenylene hydrocarbon ring systems. In some embodiments, the aryl is phenyl. Unless specifically stated otherwise in the specification, aryl can be optionally substituted with, for example, halogen, amino, nitrile, nitro, hydroxyl, alkyl, alkenyl, alkynyl, haloalkyl, alkoxy, aryl, cycloalkyl, heterocycloalkyl, heteroaryl, etc. In some embodiments, aryl can be optionally substituted with halogen, methyl, ethyl, -CN, -CF 3 , OH, -OMe, NH 2 , or -NO 2 In some embodiments, aryl is optionally substituted with halogen, methyl, ethyl, -CN, -CF 3 , OH, or -OMe. In some embodiments, the aryl is optionally substituted with halogen.

[0175] As used herein, the term "mol," when referring to PET, is the number of moles and is calculated using the molecular weight of the "PET" unit, which is 192.17 g / mol. EXAMPLES

[0176] The following examples are intended to illustrate, but not limit, the disclosed embodiments.

[0177] Example 1: Polyethylene terephthalate (1000 g) was introduced into the reactor. Dichloromethane (500 g) was added and the mixture was stirred at room temperature and atmospheric pressure for about 40 minutes. Sodium methoxide and methanol were then added to the reaction mixture and stirred and heated for 120 minutes (see table below for details of amounts, times, and temperatures).

[0178] The reaction mixture was then filtered and the filter cake was washed with methanol. The filter cake was then melted at 140° C. and filtered to remove any unreacted material. The filtered dimethyl terephthalate was then distilled under vacuum at 200° C. The liquid recovered from the filtration was distilled to recover the solvent and monoethylene glycol.

[0179] [Table 1]

[0180] Example 2: Polyethylene terephthalate (1000 g) was introduced into the reactor. DMSO (500 g) was added and the mixture was stirred at room temperature and atmospheric pressure for about 40 minutes. Sodium methoxide (45 g) and methanol (550 g) were then added to the reaction mixture, which was stirred and heated at 55° C. for 120 minutes.

[0181] The reaction mixture was then filtered and the filter cake was washed with methanol. The filter cake was then melted at 140° C. and filtered to remove any unreacted material. The filtered dimethyl terephthalate was then distilled under vacuum at 200° C. The liquid recovered from the filtration was distilled to recover the solvent and monoethylene glycol.

[0182] Dimethyl terephthalate was obtained in 89% yield.

[0183] Example 3: PET (10000 g) was treated with methanol (6000 g) at 60° C. for 1 hour. The methanol was then drained. After draining, the reactor was heated up to 60° C.-70° C. and sodium methoxide (25 wt. % in methanol) was added. Thirty minutes after the sodium methoxide addition, the remaining amount of methanol was added. The reaction was stopped 3 hours after the sodium methoxide addition. The reaction mixture was then cooled at room temperature and filtered to separate the MEG, sodium methoxide, and residual methanol from the DMT and unreacted materials. Trials 1 and 2 were not filterable using different solid-liquid separation methods (centrifugation, press filter, vacuum filter, or pressure filter), but filtration was successful for trials 3-5. As filtration was not possible, distillation of methanol was followed by distillation of MEG, and then distillation of DMT from the reaction mixture was attempted in a rotary evaporator. After recovery of methanol, the reaction mixture turned into a paste from which distillation of MEG and DMT was not possible due to side reactions with impurities.

[0184] After solid-liquid separation, for runs 3-5, the residual methanol and MEG were recovered from the liquid phase into two different fractions using a rotary evaporator. DMT was successfully recovered from the solid phase using a thin film evaporator.

[0185] The table below shows the recovery of DMT and MEG using different amounts of sodium methoxide.

[0186] [Table 2]

Claims

1. 1. A process for converting a polyester selected from the group consisting of polyethylene terephthalate and poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) to a terephthalate of formula (I): 【Chemistry 1】 R １ and R ２ is hydrogen, C １ -C ６ Alkyl, C １ -C ６ Haloalkyl, C １ -C ６ Hydroxyalkyl, optionally substituted C ３ -C ８ Cycloalkyl, optionally substituted (C １ -C ６ Alkyl) (C ３ -C ３ cycloalkyl), optionally substituted aryl, and optionally substituted (C １ -C ６ independently selected from the group consisting of (alkyl)(aryl); However, R １ Or R ２ is not hydrogen; The process comprises: (d) a solvent for swelling the polyester; (e) an alcohol-based solvent; and (f) combining a substoichiometric amount of an alkoxide into a mixture comprising:

2. R １ Or R ２ 2. The process of claim 1 , wherein is methyl.

3. 3. The process according to claim 1 or 2, characterized in that the alcoholic solvent is selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combination thereof.

4. 4. The process according to claim 3, characterized in that the alcoholic solvent is methanol.

5. 5. The process according to any one of claims 1 to 4, characterized in that the solvent for swelling the polyester is selected from the group consisting of non-polar solvents, polar aprotic solvents, polar protic solvents and any combination thereof.

6. 6. The process according to any one of claims 1 to 5, characterized in that the solvent for swelling the polyester is selected from the group consisting of DMSO, DMF, acetone, halogenated solvents, n-hexane, nitrobenzene, methanol, benzyl alcohol, benzaldehyde, and any combination thereof.

7. 7. The process according to claim 1, wherein the solvent for swelling the polyester is a halogenated solvent.

8. 7. The process according to claim 1, wherein the solvent for swelling the polyester is methanol.

9. 9. The process according to any one of claims 1 to 8, characterized in that the ratio of the solvent for swelling the polyester to the alcohol-based solvent is between about 0.1:1 and about 2:1 (w:w).

10. 10. The process according to any one of claims 1 to 9, characterized in that the ratio of the solvent for swelling the polyester to the alcohol-based solvent is between about 0.5:1 and about 1:1 (w:w).

11. 11. The process of any one of claims 1 to 10, wherein the alkoxide is selected from the group consisting of alkali metal alkoxides, alkaline earth metal alkoxides, metal alkoxides, ammonium alkoxides, and any combination thereof.

12. 12. The process according to any one of claims 1 to 11, characterized in that the alkoxide is selected from the group consisting of sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, and tetrabutylammonium methoxide.

13. 13. The process according to any one of claims 1 to 12, characterized in that the alkoxide is sodium methoxide.

14. 14. The process according to any one of claims 1 to 13, characterized in that the alkoxide is generated in situ by adding an alkali metal, an alkaline earth metal, or a metal to an alcohol-based solvent.

15. 15. The process of any one of claims 1 to 14, characterized in that the ratio of polyester to alkoxide is between about 15:1 and about 125:1 (w:w).

16. 15. The process of any one of claims 1 to 14, characterized in that the ratio of polyester to alkoxide is between about 20:1 and about 25:1 (w:w).

17. 15. The process of any one of claims 1 to 14, characterized in that the ratio of polyester to alkoxide is between about 15:1 and about 60:1 (w:w).

18. 15. The process of any one of claims 1 to 14, characterized in that the ratio of polyester to alkoxide is between about 20:1 and about 50:1 (w:w).

19. 19. The process according to any one of claims 1 to 18, characterized in that the process is carried out until a yield of about 80% of the terephthalate of formula (1) is achieved.

20. 20. The process according to any one of claims 1 to 19, characterized in that the process is carried out without external heat.

21. 20. The process according to any one of claims 1 to 19, characterized in that the process is carried out at a temperature between about 25°C and about 85°C.

22. 20. The process according to any one of claims 1 to 19, characterized in that the process is carried out at a temperature between about 25°C and about 80°C.

23. 23. The process according to any one of claims 1 to 22, characterized in that the process is carried out at atmospheric pressure.

24. 24. The process according to any one of claims 1 to 23, characterized in that the polyester is polyethylene terephthalate.

25. 25. The process of any one of claims 1 to 24, characterized in that the process further comprises the step of recovering monoethylene glycol (MEG).

26. 26. The process of any one of claims 1 to 25, characterized in that the polyester is in the form of polymer flakes and is part of the feed material.

27. 27. The process of claim 26, characterized in that the average polymer flake particle size is between 1 mm and 20 mm.

28. The process according to any one of claims 26 or 27, characterized in that the average polymer flake particle size is between 1 mm and 5 mm.

29. 1. A process for converting polyethylene terephthalate to dimethyl terephthalate, comprising: (d) a solvent for swelling the polyethylene terephthalate; (e) methanol; and (f) combining a substoichiometric amount of an alkoxide into a mixture comprising:

30. 30. The process of claim 29, wherein the solvent for swelling the polyethylene terephthalate is selected from the group consisting of halogenated solvents, DMSO, benzyl alcohol, methanol, and any combination thereof.

31. 30. The process of claim 29, characterized in that the solvent for swelling the polyethylene terephthalate is a halogenated solvent.

32. 30. The process according to claim 29, characterized in that the solvent for swelling the polyethylene terephthalate is methanol.

33. 33. The process of any one of claims 29 to 32, characterized in that the ratio of polyethylene terephthalate to alkoxide is between about 20:1 and about 25:1 (w:w).

34. 33. The process of any one of claims 29 to 32, characterized in that the ratio of polyester to alkoxide is between about 15:1 and about 60:1 (w:w).

35. 33. The process of any one of claims 29 to 32, characterized in that the ratio of polyester to alkoxide is between about 20:1 and about 50:1 (w:w).

36. 36. The process according to any one of claims 29 to 35, characterized in that the alkoxide is selected from the group consisting of sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, and tetrabutylammonium methoxide.

37. 37. The process according to any one of claims 29 to 36, characterized in that the alkoxide is sodium methoxide.

38. 38. The process according to any one of claims 29 to 37, characterized in that the ratio of the solvent for swelling the polyethylene terephthalate to methanol is between about 0.5:1 and about 1:1 (w:w).

39. 39. The process of any one of claims 29 to 38, characterized in that the process is carried out until a yield of about 80% of dimethyl terephthalate is achieved.

40. 40. The process according to any one of claims 29 to 39, characterized in that the process is carried out without external heat.

41. 40. The process according to any one of claims 29 to 39, characterized in that the process is carried out at a temperature between about 25°C and about 85°C.

42. 40. The process according to any one of claims 29 to 39, characterized in that the process is carried out at a temperature between about 25°C and about 80°C.

43. 43. The process according to any one of claims 29 to 42, characterized in that the process is carried out at atmospheric pressure.

44. 44. The process of any one of claims 29 to 43, characterized in that the process further comprises the step of recovering monoethylene glycol (MEG).

45. 45. The process of any one of claims 29 to 44, characterized in that the polyethylene terephthalate is in the form of polymer flakes and is part of the feed material.

46. 46. ​​The process of claim 45, characterized in that the average polymer flake particle size is between 1 mm and 20 mm.

47. The process according to claim 45 or 46, characterized in that the average polymer flake particle size is between 1 mm and 5 mm.

48. 48. Dimethyl terephthalate (DMT) prepared using the process of any one of claims 1 to 47.

49. 48. Monoethylene glycol (MEG) prepared using the process of any one of claims 1 to 47.

50. 1. A reaction mixture comprising: (e) a polyester selected from polyethylene terephthalate and poly(ethylene glycol-co-1,4-cyclohexanediyldimethanol terephthalate); (f) a solvent for swelling the polyester; (g) an alcohol-based solvent; and (h) a reaction mixture comprising a substoichiometric amount of an alkoxide.

51. 51. The reaction mixture of claim 50, wherein the alcoholic solvent is selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combination thereof.

52. 52. The reaction mixture of claim 50 or 51, characterized in that the solvent for swelling the polyester is selected from the group consisting of non-polar solvents, polar aprotic solvents, polar protic solvents, and any combination thereof.

53. 53. The reaction mixture of any one of claims 50 to 52, wherein the solvent for swelling the polyester is a halogenated solvent.

54. 53. The reaction mixture of any one of claims 50 to 52, wherein the solvent for swelling the polyester is methanol.

55. 55. The reaction mixture according to any one of claims 50 to 54, characterized in that the alcoholic solvent is methanol.

56. 56. The reaction mixture of any one of claims 50 to 55, wherein the ratio of the solvent for swelling the polyester to the alcoholic solvent is between about 0.5:1 and about 1:1 (w:w).

57. 56. The reaction mixture of any one of claims 50 to 55, wherein the ratio of polyester to alkoxide is between about 15:1 and about 30:1 (w:w).

58. 56. The reaction mixture of any one of claims 50 to 55, wherein the ratio of polyethylene terephthalate to alkoxide is between about 20:1 and about 25:1 (w:w).

59. 59. The reaction mixture of any one of claims 50 to 58, wherein the ratio of polyester to alkoxide is between about 15:1 and about 60:1 (w:w).

60. 60. The reaction mixture of any one of claims 50 to 59, wherein the ratio of polyester to alkoxide is between about 20:1 and about 50:1 (w:w).

61. 61. The reaction mixture according to any one of claims 50 to 60, characterized in that the alkoxide is selected from the group consisting of sodium methoxide, potassium ethoxide, aluminum tri-n-propoxide, and tetrabutylammonium methoxide.

62. 62. The reaction mixture according to any one of claims 50 to 61, characterized in that the alkoxide is sodium methoxide.

63. 63. The reaction mixture of any one of claims 50 to 62, characterized in that the polyester is polyethylene terephthalate.

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