Macrocyclic polyester oligomers directly produced from diols and aromatic dicarboxylic acids, and related methods.

Abstract

Known methods for producing macrocyclic oligomers include either (i) depolymerizing a pre-prepared polymer using a highly dilution process to establish a thermodynamic equilibrium in which the cyclic compound is preferred over the polymer, or (ii) using an acid chloride and a diol in one or two solvent systems. As presented herein, by using selected compositions, moisture-resistant catalysts, suitable solvents, and limited concentration profiles, it has been found that macrocyclic oligomers can be produced directly in a one-step process without the need to first produce a polymer or perform any other additional process steps.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority and benefit of U.S. Provisional Patent Application No. 63 / 454,348, filed on March 24, 2023, the content of which is hereby incorporated by reference in its entirety.

[0002] Technical Field The present invention generally relates to polymer processing techniques at all scales, such as laboratories, pilot plants, and industrial scales. In certain embodiments, the present invention relates to directly (e.g., in a one - step process) producing macrocyclic polyester oligomers by reacting diols and aromatic dicarboxylic acids in a solvent in the presence of a catalyst.

Background Art

[0003] Background Known methods for producing macrocyclic polyester oligomers (referred to as "cyclic compounds" or "cyclic oligomers" or "macrocyclic polyester oligomers" or "MPOs") involve either (i) depolymerizing a pre - prepared polymer using a high - dilution process to establish a thermodynamic equilibrium in which the cyclic compound is favored over the polymer, or (ii) using acid chlorides and diols in one or two solvent systems.

[0004] The preparation of cyclic arylates is described, for example, in U.S. Patents 4,757,132, 4,927,904, and 5,136,018. In all of these, cyclic arylates are produced by mixing various acid dioxides in a nonpolar solvent with various bisphenol salts in an aqueous solution in a nonpolar solvent and reacting them in the presence of a phase transfer catalyst. Each of these patents describes a batch reaction in which one or both of the reactants are slowly supplied to a solvent reservoir containing the reactants and the phase transfer catalyst. These patents use a slow supply rate, solvents in the reactor, and a combination of two separate phases created using both polar and nonpolar solvents to increase the reactant concentration, thereby favoring intramolecular reactants over intermolecular reactants.

[0005] U.S. Patent No. 4,829,144 describes a method for preparing an aqueous solution of a bisphenol salt by dissolving a diacid in a nonpolar solvent. These solutions are added to a vessel containing a nonpolar solvent and an amine catalyst. In one example, the bisphenol salt is created in situ by subsequently supplying the diacid solution to a reactor containing an existing solvent reservoir.

[0006] U.S. Patent No. 4,927,904 describes how the yield can be improved by controlling the concentration and rate of addition and adding the product at an equimolar rate to a reactor containing an existing solvent. This process uses the same reactants as U.S. Patent No. 4,829,144.

[0007] U.S. Patent No. 5,136,018 discloses improved products obtained by creating low-melting-point products using two types of diacids. In all three cases described in this patent, pseudo-high dilution was identified as an improvement over simple high dilution.

[0008] Processes for producing cyclic oligomers of alkene diols using diacids are also described. For example, U.S. Patent No. 5,039,783 describes an anhydrous process using a nonpolar solvent with an amine catalyst as the diacid solvent and the solvent in the reactor, and a polar solvent as the solvent for the diol. The addition of the catalyst and diacid separately is also described. The catalyst can be added to the reactor before the reactants, separately, or simultaneously with the diol.

[0009] U.S. Patent No. 5,231,161 discloses the reasons for using both polar and nonpolar solvents when it is necessary to solubilize diols. In the process described in this patent, the diol is reacted in a separate step to produce a bis-ester oligomer, which is then dissolved in the same nonpolar solvent as the diacid, thus eliminating the need for a polar solvent. This patent also describes the use of two different amines as catalysts. The first amine is a sterically unhindered tertiary amine described in U.S. Patent No. 5,039,783. The second amine is one in which the majority of this amine is substituted with a trialkylamine containing 1 to 6 carbon atoms in an alkyl group, with triethylamine being preferred.

[0010] U.S. Patents 5,039,783 and 5,231,161 both describe a pseudo-high dilution method that prioritizes intermolecular reactions over intramolecular reactions, thereby potentially leading to the formation of high molecular weight polymers, as an improvement over high dilution.

[0011] Another method for generating cyclic compounds involves establishing highly diluted solutions in which cyclic compounds constitute the vast majority. This method is described in U.S. Patent No. 8,283,437. Many of the described methods focus on polybutylene terephthalate, using the polymer as a raw material. This allows for stoichiometric control and reduces the need to remove end groups such as water or methanol when reacting from monomers. While this method produces cyclic arylates, the resulting product has a melting point exceeding 300°C, severely limiting its commercial utility.

[0012] U.S. Patent No. 4,740,583 discloses cyclic polycarbonates and composites made therefrom. The described process for producing the cyclic compounds utilizes a two-phase system of water and an organic solid. No method for forming the composites other than using a transesterification catalyst is described.

[0013] U.S. Patent No. 6,627,830 discloses a resorcinol-containing polyarylate composite of a certain composition and properties. Because it is difficult to incorporate fibers or other fillers into high molecular weight amorphous polymers, the upper limit for fibers is stated as 60 weight percent. In-situ polymerized thermoplastic composites are commercially available in polybutylene terephthalate, nylon 6, and polyacrylate. These have glass transition temperatures below 110°C. Few polymers have glass transition temperatures above 140°C, and all of them have high melt viscosity. This makes the incorporation of continuous or long fibers difficult. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] U.S. Patent No. 4,757,132 [Patent Document 2] U.S. Patent No. 4,927,904 [Patent Document 3] U.S. Patent No. 5,136,018 [Patent Document 4] U.S. Patent No. 4,829,144 [Patent Document 5] U.S. Patent No. 5,039,783 [Patent Document 6] U.S. Patent No. 5,231,161 [Patent Document 7] U.S. Patent No. 8,283,437 [Patent Document 8] U.S. Patent No. 4,740,583 [Patent Document 9] U.S. Patent No. 6,627,830 [Overview of the Initiative] [Means for solving the problem]

[0015] overview This specification presents macrocyclic oligomer compositions and methods for preparing them. In certain embodiments, it has been found that macrocyclic oligomers can be directly produced in a one-step process without the need to first produce polymers or perform any other additional process steps, by using selected compositions, moisture-resistant catalysts, suitable solvents, and limited concentration profiles.

[0016] Most conventional methods for generating cyclic oligomers are designed to produce oligomers that can be ring-opened and polymerized to form commercially available polyesters. While currently available polymers are produced from a wide variety of diols, they are primarily produced using terephthalic acid (TPA). The preferential use of TPA imparts improved thermal and mechanical properties compared to polymers based on isophthalic acid (IPA). This choice for improved properties presents a challenge to directly generating cyclic oligomers from monomers, as TPA is less soluble than IPA in commercially preferred solvents.

[0017] As described herein, in certain embodiments, it has been found that by using IPA as the main basis for oligomers and subsequent polymers, a lower-cost and simpler process for the production of cyclic compounds can be achieved. The cyclic oligomers thus produced can be used, for example, in thermoplastic composites. This approach can be used to produce cyclic compounds and, by focusing on the selection of diols, the final polymer properties can be extended.

[0018] In certain embodiments, one feature of the methods described herein is the ability to produce cyclic oligomers using aromatic dicarboxylic acids having at least 60% isophthalic acid and the balance terephthalic acid. In certain embodiments, the diols used may be ethylene glycol, butanediol, cyclohexanedimethanol, bisphenol A, resorcinol, or hydroquinone, which may be used separately or in combination.

[0019] In certain embodiments, another feature of the methods described herein is the use of a solvent in which each of the reactants is present in solution at a molar concentration of 0.02 to 0.3. If possible, it is preferred that the cyclic compound precipitates from the solution at a temperature below the reaction temperature. In certain embodiments, useful solvents can include dichloromethane, tetrahydrofuran, toluene, xylene, and chlorobenzene. In some embodiments, neat diol is supplied as a fluid without the use of additional solvents.

[0020] In certain embodiments, another feature of the methods described herein is the use of a moisture-tolerant catalyst. Since water is generated as a byproduct of the esterification reaction, the use of a moisture-tolerant catalyst is a preferred element of the method. These catalysts may be, for example, organic bases such as triethylamine, N,N-diisopropylethylamine (DIPEA), N-methylmorpholine, diisopropylamine, 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), 4-dimethylaminopyridine (DMAP), pyridinium p-toluenesulfonate (PPTS), triazabicyclodecene (TBD), imidazole, and / or quaternary ammonium salts (e.g., hexadecyltrimethylammonium bromide). A moisture-tolerant catalyst is a catalyst that maintains its usefulness even in the presence of a small but non-negligible amount of water, for example, an amount of water in the range of about 0.02 to 0.6 molar concentration. For example, in some embodiments, a moisture-tolerant catalyst, as the term is used herein, is a catalyst that maintains its usefulness even in the presence of a non-negligible amount of water up to 0.02 molar concentration. In other embodiments, a moisture-tolerant catalyst is a catalyst that maintains its usefulness even in the presence of a non-negligible amount of water up to 0.05 molar concentration, 0.1 molar concentration, 0.2 molar concentration, 0.3 molar concentration, 0.4 molar concentration, 0.5 molar concentration, or 0.6 molar concentration. The potential moisture tolerance of TBD is described, for example, in Jeung Gon Kim et al., ''Triazabicyclodecene: A versatile catalyst for polymer synthesis,'' Journal of Polymer Science, Vol. 62, Issue 1, January 1, 2024, pp. 42-91.

[0021] In certain embodiments, the methods described herein use a heterogeneous version of the catalyst. This enables a continuous process in which a carefully prepared, stoichiometrically balanced solution of reactants passes over a catalyst bed with a residence time sufficient to allow for complete conversion.

[0022] For example, (i) a solution of IPA (e.g., 0.1 molar concentration) in a solvent (e.g., toluene and / or xylene) and (ii) a solution of bisphenol A (BPA) (e.g., 0.01 molar concentration) and a TBD catalyst (e.g., 0.01 molar concentration) can be supplied together to a continuous reactor and brought into contact. After the reaction is complete, the catalyst can be removed via an ion exchange resin, and the by-products water and solvent can be separated from each other and from the product using known distillation methods.

[0023] For example, if the reactants are soluble within a given range and the catalyst is moisture-resistant, other product formulations, catalysts, and solvents can be used.

[0024] In one embodiment, the present invention relates to a method for producing a macrocyclic polyester oligomer, wherein the method comprises the step of reacting an aromatic dicarboxylic acid with a diol in the presence of a catalyst to form a macrocyclic polyester oligomer, and the catalyst is a moisture-resistant catalyst.

[0025] In another embodiment, the present invention relates to a method for producing a polyester (e.g., polyarylate), wherein the method comprises the step of reacting an aromatic dicarboxylic acid with a diol in the presence of a catalyst to form a polyester, the catalyst being a moisture-resistant catalyst.

[0026] In certain embodiments, the catalyst comprises an organic base selected from the group consisting of triethylamine, N,N-diisopropylethylamine (DIPEA), N-methylmorpholine, diisopropylamine, 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), 4-dimethylaminopyridine (DMAP), pyridinium p-toluenesulfonate (PPTS), triazabicyclodecene (TBD), imidazole, and quaternary ammonium salts (e.g., hexadecyltrimethylammonium bromide).

[0027] In certain embodiments, the catalyst comprises triazabicyclodecene (TBD).

[0028] In certain embodiments, the catalyst is a heterogeneous catalyst (e.g., a solid or deposited on a solid), and the method includes the step of passing a solution containing aromatic dicarboxylic acids and diols over a catalyst bed (e.g., the method is a continuous process).

[0029] In a particular embodiment, the method comprises the step of reacting an aromatic dicarboxylic acid with a diol in a solvent solution, the solvent being selected from the group consisting of dichloromethane, tetrahydrofuran, toluene, xylene, and chlorobenzene.

[0030] In a particular embodiment, the method comprises the step of reacting an aromatic dicarboxylic acid with a diol in a solvent solution, wherein the aromatic dicarboxylic acid is present at a concentration of 0.02 to 0.3 molars in the solution, and the diol is present at a concentration of 0.02 to 0.3 molars in the solution.

[0031] In certain embodiments, at least 60 wt.% of the aromatic dicarboxylic acid is isophthalic acid (IPA) (for example, the remainder, e.g., 40 wt.% or less, is terephthalic acid (TPA)).

[0032] In certain embodiments, the aromatic dicarboxylic acid is (i) isophthalic acid (IPA), or (ii) terephthalic acid (TPA), or (iii) a combination of IPA and TPA.

[0033] In a particular embodiment, the polyester is a polyarylate, and the method further includes the step of producing a macrocyclic polyester oligomer from a polyarylate by re-equilibrating the polyarylate (e.g., in solution, in the presence of a catalyst) thereby producing a macrocyclic polyester oligomer.

[0034] In a particular embodiment, the polyester is polyarylate (for example, a component made using polyarylate, which may also include a reinforcing filler or fibers), and the method further includes the step of producing a macrocyclic polyester oligomer from polyarylate by re-equilibrating the polyarylate (for example, in solution, in the presence of a catalyst) thereby producing a macrocyclic polyester oligomer (and, for example, recycling a portion made using polyarylate).

[0035] In a particular embodiment, the method further includes the step of producing a composite containing at least 60 wt.% of a reinforcing material using a macrocyclic polyester oligomer or polyester.

[0036] Elements and features of embodiments described in relation to one aspect of the present invention may be applied in relation to other aspects of the present invention.

[0037] The above and other purposes, aspects, features, and advantages of this disclosure will be made clearer and better understood by referring to the following description in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0038] [Figure 1] Figure 1 is a schematic diagram of a method for producing a macrocyclic polyester oligomer or polyester from the reaction of a diol and an aromatic dicarboxylic acid in the presence of a catalyst, according to a particular embodiment of the present invention. [Modes for carrying out the invention]

[0039] The features and advantages of this disclosure will become clearer when the following detailed description is read in conjunction with the accompanying drawings. In the drawings, similar reference letters identify corresponding elements throughout. In the drawings, similar reference numbers generally indicate identical elements, functionally similar elements, and / or structurally similar elements.

[0040] Detailed description of the invention The claimed compositions, methods, and processes of the present invention are intended to encompass variations and adaptations developed using the information of the embodiments described herein. Adaptations and / or modifications of the compositions, methods, and processes described herein may be carried out as intended by this description.

[0041] Throughout this description, where a composition is described as having, including, or comprising certain components, or where a process and method is described as having, including, or comprising certain steps, it is intended that there are further compositions of the present invention that are essentially composed of or comprise the described components, and that there are processes and methods according to the present invention that are essentially composed of or comprise the described processing steps.

[0042] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operable. Furthermore, two or more steps or actions can be performed simultaneously.

[0043] Any reference in this specification to any publication, for example, in the background section above, does not constitute an admission that such publication serves as prior art with respect to any of the claims presented herein. The background section is provided for clarity and is not intended to describe prior art relating to any claim. Any documents referenced in this specification, for example, in the background section above, are incorporated herein by reference in their entirety. In the event of any inconsistency in the meaning of any particular term, the meaning provided in the text of this specification that is not incorporated by reference shall prevail.

[0044] Headings are provided for the convenience of the reader, and the presence and / or placement of headings is not intended to limit the scope of the subject matter described herein.

[0045] As used herein, “macrocyclic” or “macro-cyclic” means a cyclic molecule having at least one ring in its molecular structure, wherein the molecular structure contains five or more atoms that covalently bond to form a ring.

[0046] As used herein, “oligomer” is understood to mean a molecule containing one or more identifiable structural repeating units of the same or different formulas.

[0047] As used in this application, the terms “macro-cyclic polyester oligomer,” “cyclic compound,” “cyclic oligomer,” “macrocyclic polyester oligomer,” and “MPO” are used synonymously. These terms are understood to mean macrocyclic oligomers containing structural repeating units having ester functional groups. A macrocyclic polyester oligomer typically refers to multiple molecules of one specific repeating unit formula. However, macrocyclic polyester oligomers may also include multiple molecules of different or mixed formulas having varying numbers of the same or different structural repeating units. Therefore, the terms “macrocyclic polyester oligomer” and “macrocyclic polyester oligomers” are interchangeable. Similarly, the terms “macrocyclic polyester oligomer” and “macrocyclic oligoester” are used interchangeably herein. A macrocyclic polyester oligomer may be a copolyester or multicomponent polyester oligomer, i.e., an oligomer having two or more different structural repeating units having ester functional groups within a single cyclic molecule.

[0048] General information relating to macrocyclic polyester oligomers can be found in International (PCT) Patent Application Publication No. 2016126757, titled "Methods for preparation of macrocyclic polyester oligomer from linear polyester," the contents of which are incorporated herein by reference.

[0049] Macrocyclic polyester oligomers that can be prepared or used using the methods described herein include formula [ka] This includes, but is not limited to, macrocyclic poly(alkylenedicarboxylate) oligomers having a repeating structural unit [wherein A is an alkylene, cycloalkylene, monooxyalkylene, or polyoxyalkylene group, and B is a divalent aromatic group or alicyclic group].

[0050] Macrocyclic polyester oligomers include, but are not limited to, macrocyclic poly(1,4-butylene terephthalate) (cPBT), macrocyclic poly(1,3-propylene terephthalate) (cPPT), macrocyclic poly(1,4-cyclohexylenedimethylene terephthalate) (cPCT), macrocyclic poly(ethylene terephthalate) (cPET), macrocyclic polytrimethylene terephthalate PTT (cPTT), and macrocyclic poly(1,2-ethylene 2,6-naphthalenedicarboxylate) (cPEN) oligomers, as well as copolyester oligomers containing two or more of the repeating units described above.

[0051] The methods described herein can be used to produce macrocyclic homopolyesters and copolyester oligomers. In one embodiment, the macrocyclic ester homooligomers and cooligomers produced by the methods described herein include the formula [ka] This includes oligomers having a general structural repeating unit of [wherein A' is an alkylene, cycloalkylene, or monooxyalkylene or polyoxyalkylene group, and A' may be substituted, unsubstituted, branched, and / or linear]. Examples of macrocyclic polyester oligomers of this type include butyrolactone and caprolactone with a degree of polymerization of 1, and 2,5-dioxo-1,4-dioxane and lactide with a degree of polymerization of 2. The degree of polymerization may be 3, 4, 5, or higher. The molecular structures of 2,5-dioxo-1,4-dioxane and lactide are shown below, respectively. [ka]

[0052] In general, macrocyclic polyester oligomers (MPOs) produced by the methods described herein contain species with different degrees of polymerization, but in certain embodiments, MPOs containing high concentrations of specific species may be produced. Here, the degree of polymerization (DP) for MPO refers to the number of identifiable structural repeating units in the oligomer backbone. The structural repeating units may have the same molecular structure or different molecular structures. For example, MPOs may contain dimers, trimers, tetramers, pentamers, and / or other species. In certain embodiments, MPOs are primarily dimers, trimers, tetramers, and / or pentamers (e.g., essentially composed of them). In certain embodiments, MPOs are primarily trimers, tetramers, and / or pentamers (e.g., C3+C4+C5) (e.g., essentially composed of them).

[0053] As described herein, in certain embodiments, aromatic dicarboxylic acids are used. Examples of aromatic dicarboxylic acids include, for example, phthalic acids, isophthalic acids and terephthalic acids, as well as their ortho, meta and para isomers.

[0054] As described herein, terephthalic acid (TPA) is an organic compound having the chemical structure represented by the formula C6H4(CO2H)2, either or both of the following: [ka]

[0055] As described herein, isophthalic acid (IPA) is an organic compound having the formula C6H4(CO2H)2. IPA is an isomer of phthalic acid and terephthalic acid. IPA has the following chemical structure: [ka]

[0056] Where a method described herein refers to the use of terephthalic acid (TPA), certain embodiments of those methods are intended to include variations in which a dialkyl terephthalate, such as dimethyl terephthalate (DMT), may be used instead of at least some of the TPA. For example, a method described herein in which a reaction is carried out using TPA and a diol is intended to include embodiments / variations in which DMT is used instead of at least some of the TPA.

[0057] As used herein, “substantially absent” means that the composition does not contain in significant amounts any of the substances described as substantially absent (e.g., water and / or methanol). In some embodiments, the composition may contain less than 20%, 10%, 5%, 2%, 1%, 0.5%, 0.1%, or 0.01% of the substances described as substantially absent.

[0058] Various organic solvents may be used to carry out the methods described herein. In some embodiments, the solvent includes at least one member selected from the group consisting of dichloromethane, tetrahydrofuran, toluene, xylene, and chlorobenzene. In some embodiments, the organic solvent includes at least one member selected from the group consisting of tetradecane, hexadecane, octadecane, toluene, xylene, trimethylbenzene, tetramethylbenzene, ethylbenzene, propylbenzene, naphthalene, methylnaphthalene, biphenyl, triphenyl, diphenyl ether (or its halogenated derivatives), anisole, methylene chloride, dimethyoxybenzene, chlorobenzene, dichlorobenzene, trichlorobenzene, chloronaphthalene, dichloronaphthalene, and / or perfluorocarbons. In some embodiments of the methods and processes described herein, the organic solvent includes a high-purity hydrocarbon solvent (e.g., Drakesol 165, e.g., manufactured by Orica Chemicals, composed of acid-treated diesel distillates). In some embodiments, the organic solvent comprises one or more components selected from the group consisting of oDCB (ortho-dichlorobenzene), toluene, o-xylene, pyridine, triethylamine, heptane, dibutyl ether, decane, and trichlorobenzene (TCB). In some embodiments, the organic solvent is xylene or contains xylene. In some embodiments, the organic solvent comprises perfluoro compounds such as perfluoro(tri-n-butylamine) and perfluoro(tri-n-pentylamine). The organic solvent used preferably has a boiling point of about 110°C or higher. As used herein, the term “solvent” refers to a solvent added to the reaction mixture, but does not include substances that may become part of the reaction mixture as byproducts of the reactions described herein.

[0059] As described herein, preferred embodiments utilize moisture-resistant catalysts. Such catalysts may include, for example, one or more organic bases such as triethylamine, N,N-diisopropylethylamine (DIPEA), N-methylmorpholine, diisopropylamine, 1,8-diazabicyclo(5.4.0)undeca-7-ene (DBU), 4-dimethylaminopyridine (DMAP), pyridinium p-toluenesulfonate (PPTS), triazabicyclodecene (TBD), imidazole, and quaternary ammonium salts (e.g., hexadecyltrimethylammonium bromide). Moisture-resistant catalysts are those that maintain their usefulness in the presence of small but significant amounts of water, for example, water at concentrations of about 0.02 to 0.6 molars. For example, in some embodiments, a moisture-resistant catalyst is, as used herein, a catalyst that maintains its usefulness in the presence of significant amounts of water up to a concentration of 0.02 molars. In other embodiments, a moisture-resistant catalyst is one that maintains its usefulness in the presence of a non-negligible amount of water up to a concentration of 0.05 molars, 0.1 molars, 0.2 molars, 0.3 molars, 0.4 molars, 0.5 molars, or 0.6 molars. The potential of moisture resistance of TBD is described, for example, in Jeung Gon Kim et al., "Triazabicyclodecene: A versatile catalyst for polymer synthesis," Journal of Polymer Science, Vol. 62, Issue 1, January 1, 2024, pp. 42-91. In certain embodiments, the method uses a heterogeneous version of the catalyst. This facilitates a continuous process in which, for example, a stoichiometrically balanced solution of reactants passes over the catalyst bed with a residence time sufficient to allow for satisfactory (e.g., complete or near-complete) conversion.

[0060] Other catalysts that may be used in the methods described herein (in addition to or instead of the moisture-resistant catalysts described herein) include, but are not limited to, members selected (or derived) from the group consisting of organotitanates and / or organotin compounds, such as 2-ethylhexyl titanate, tetrakis-(2-ethylhexyl) titanate, tetrabutyl titanate, tetraisopropyl titanate, alkoxy titanate, titanium methoxide, titanium ethoxide, diisopropoxide bis(2,4-pentanedione), triethanolamine titanium in an alcohol solvent, and butanediol titanate, or heterogeneous derivatives thereof.

[0061] In some embodiments, the provided method utilizes a catalyst-containing solid (e.g., a support or substrate). In certain embodiments, the catalyst-containing solid is a member (or includes such member) selected from the group including catalyst-coated glass beads, catalyst-coated glass fibers, catalyst-coated silica gel, catalyst-coated melamine-formaldehyde solids (e.g., solids, beads, etc.), and magnetic iron oxide to which the catalyst is attached. In some embodiments, the catalyst-containing solid is or includes catalyst-coated glass beads pre-treated with a diol. While not bound by any particular theory, pre-treating the solid catalyst with a diol may be advantageous because it replaces the OH groups on the solid catalyst with OR groups (i.e., ether groups derived from the diol), thereby avoiding the formation of water. In some embodiments, the catalyst-containing solid is catalyst-coated glass beads pre-treated with 1,4-butanediol.

[0062] In certain embodiments, the method described herein uses catalyst-coated glass beads over which the reaction solution passes. In other embodiments, catalyst-coated silica gel may be used, or another catalyst-coated (or otherwise catalyst-containing) solid may be used, for example, in a packed bed or column.

[0063] In some embodiments of the methods and processes described herein, the reaction mixture includes a diol. In certain embodiments, the diol is ethylene glycol, butanediol, cyclohexanedimethanol, bisphenol A, resorcinol, and / or hydroquinone, or includes ethylene glycol, butanediol, cyclohexanedimethanol, bisphenol A, resorcinol, and / or hydroquinone. In certain embodiments, the diol is polyethylene glycol, polypropylene glycol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethylpropane-1,3-diol, 2-butyl-2-ethylpropane-1,3-diol, 1,5-hexanediol, 1,6-hexanediol, 1,8-octanediol, The diols include, but are not limited to, 1,10-decanediol, 1,12-dodecanediol, 2,2,4,4-tetramethylcyclobutane-1,3-diol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and / or 1,4-cyclohexanediethanol. In some embodiments, the diol is polyethylene glycol. In some embodiments, the diol is butanediol. In some embodiments, the diol is 1,4-butanediol. In some embodiments of the methods and processes described herein, the reaction mixture contains phenol. In certain embodiments, the phenol is resorcinol. In other embodiments, the phenol is hydroquinone.

[0064] As described herein, the method can be used to produce either cyclic oligomers or polymers by direct esterification. For example, polyarylates (PARs) can be produced. Polyarylates are a family of aromatic polyesters made from aromatic dicarboxylic acids and bisphenols.

[0065] The methods, systems, and processes described herein are intended to encompass scale-ups, modifications, and adaptations developed using information from the embodiments described herein. For example, the methods described herein include pilot plant and plant-scale manufacturing processes whose feasibility has been demonstrated by laboratory-scale experiments described herein. The chemical reactions described herein can be carried out using reactors known to technicians in the field of polymer manufacturing and processing, such as, but are not limited to, batch reactors, plug-flow reactors, continuous stirred-tank reactors, packed-bed reactors, slurry reactors, fluidized-bed reactors, and columns. The chemical reactions described herein can be carried out in batch, semi-continuous, and / or continuous operations.

[0066] Scaling up systems from laboratory scale to plant scale can be carried out by engineers in the field of polymer manufacturing and processing. For example, engineers in this field can select reactor types, design experiments to acquire dynamic data, develop and apply models for reactor design, develop economically optimal reactor designs, and / or validate reactor designs through pilot plant and / or large-scale reactor experiments. General information on the design of reactor systems for reactor and product manufacturing can be found, for example, in "Kinetics and Reaction Engineering," John L. Falconer, editor, in The Engineering Handbook, Section X, Richard C. Dorf, editor-in-chief, CRC Press, Inc., ISBN 0-8493-8344-7, pp. 785-829 (1995).

[0067] Any suitable techniques for the separation, isolation, and purification of materials, such as distillation, extraction, reaction extraction, adsorption, absorption, stripping, crystallization, evaporation, sublimation, diffusion separation, adsorption bubble separation, membrane separation, and / or techniques for fluid particle separation, can be adapted for application in manufacturing processes encompassed in various embodiments of the methods described herein. General information on separation processes and their design can be found, for example, in "Separation Processes," Klaus Timmerhaus, editor, in The Engineering Handbook, Section VIII, Richard C. Dorf, editor-in-chief, CRC Press, Inc., ISBN 0-8493-8344-7, pp. 579-657 (1995).

[0068] The methods, systems, and processes described herein may also include pumps, heat exchangers, and apparatus for handling gaseous, liquid, and / or solid-phase materials, which are known to technicians in the field of polymer production and processing.

[0069] The embodiments described herein may be carried out as part of a continuous, semi-continuous, or batch process. The reactor may be single-stage or multi-stage. The methods of the present invention may be combined with reactors, systems, or processes known in the art, and the methods of the present invention may be supplemented with reactors, systems, or processes known in the art.

[0070] Figure 1 is a schematic diagram of a method for producing a macrocyclic polyester oligomer or polyester from the reaction of a diol and an aromatic dicarboxylic acid in the presence of a catalyst, according to an exemplary embodiment.

[0071] In certain embodiments, the catalyst comprises an organic base, such as triethylamine, N,N-diisopropylethylamine (DIPEA), N-methylmorpholine, diisopropylamine, 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), 4-dimethylaminopyridine (DMAP), pyridinium p-toluenesulfonate (PPTS), triazabicyclodecene (TBD), imidazole, and / or a quaternary ammonium salt (e.g., hexadecyltrimethylammonium bromide).

[0072] In certain embodiments, the catalyst comprises triazabicyclodecene (TBD). In certain embodiments, the catalyst is a heterogeneous catalyst (e.g., solid or deposited on a solid), and the method comprises the step of passing a solution containing aromatic dicarboxylic acids and diols over a catalyst bed (e.g., the method is a continuous process).

[0073] In a particular embodiment, the method comprises the step of reacting an aromatic dicarboxylic acid with a diol in a solvent solution, the solvent being selected from the group consisting of dichloromethane, tetrahydrofuran, toluene, xylene, and chlorobenzene.

[0074] In a particular embodiment, the method comprises the step of reacting an aromatic dicarboxylic acid with a diol in a solvent solution, wherein the aromatic dicarboxylic acid is present at a concentration of 0.02 to 0.3 molars in the solution, and the diol is present at a concentration of 0.02 to 0.3 molars in the solution.

[0075] In certain embodiments, at least 60 wt.% of the aromatic dicarboxylic acid is isophthalic acid (IPA) (for example, the remainder, e.g., 40 wt.% or less, is terephthalic acid (TPA)).

[0076] In certain embodiments, the aromatic dicarboxylic acid is (i) isophthalic acid (IPA), or (ii) terephthalic acid (TPA), or (iii) a combination of IPA and TPA.

[0077] In a particular embodiment, the method further includes the step of producing a composite containing at least 60 wt.% of a reinforcing material using a macrocyclic polyester oligomer or polyester. [Examples]

[0078] Experimental Examples The following are experimental examples illustrating embodiments described herein.

[0079] Example 1 A 250 ml round-bottom flask was fitted with a stirring bar, a Dean-Stark trap, a reflux column, and a heating mantle. 1.66 g of isophthalic acid (IPA), 1.10 g of resorcinol (RS), and 125 ml of toluene were added to the flask. The flask was brought under reflux. Undissolved IPA particles were observed for more than 5 minutes during reflux. Next, 0.14 g of 1,5,7-triazabicyclo[4.4.0]deca-5-ene (TBD) was added. Fifteen minutes after TBD addition, the solution was clarified, held for a further hour, then cooled, and the solid was filtered. After drying, the solid was gum-like and resinous. Differential scanning calorimetry showed a broad, shallow peak at approximately 239°C, consistent with the product being a low molecular weight linear oligomer. The published melting point of RS-IPA polymer is 245°C.

[0080] High molecular weight polymers can be obtained by using known methods to improve yield, such as increasing the reaction concentration and / or increasing the time or temperature. These can then be used in a wide variety of commercial processes to produce components, or the polymers can be re-equilibriumized to cyclic oligomers in a highly dilution reactor using a suitable catalyst.

[0081] By carrying out the reaction at a higher dilution ratio, cyclic compounds can be directly produced.

[0082] The fact that the solution was only clarified after the addition of TBD indicates that the reaction can proceed independently of the solubility of the diacitor in the solvent, and that the catalytic action on the diacitor is sufficient to introduce it into the reaction. This makes it possible to incorporate either or both IPA and TPA into the reaction product.

[0083] Surprisingly, it was found that the reaction proceeded and the mixture was clarified when toluene, resorcinol, and TBD were used together. While not bound by any particular theory, it is thought that TBD acts on IPA, incorporating it into the solution, where it reacts with the diol.

[0084] Example 2 Example 1 was repeated with half the concentration, i.e., 0.837 g of IPA, 0.552 g of RS, 0.073 g of TBD, and 125 ml of toluene. Fifteen minutes after reflux was reached, the reaction solution was found to be clear and no suspended solids remained. Upon stopping heating, a white free-flowing powder precipitate formed immediately and was filtered off while still hot. Upon cooling the filtrate, further free-flowing powder precipitated. Both samples were dried without further heating and then weighed. The thermally filtered sample yielded 0.926 g, and the dried thermally filtered sample yielded 0.450 g. Assuming that the thermally filtered sample contained any crystallized cyclic oligomers and unreacted IPA, and the filtrate contained any unreacted RS and TBD, this indicates that 32% of the RS was consumed. DSC was performed on the thermally filtered sample. The thermally filtered sample showed distinct peaks at 310°C, 317°C, and 339°C. The published melting point of RS-IPA polymers is 245°C. The peaks actually observed indicate that they are crystalline cyclic oligomers.

[0085] In the above version of the experiment, TBD, IPA, and solvent were added and held for 5 minutes, during which no clarification was observed. Then, upon adding RS, clarification was observed. While not adhering to any particular theory, this is considered to demonstrate that the reaction is proceeding, rather than simply demonstrating the property of either TBD or RS to be solvated with toluene.

[0086] Example 3 Example 2 was repeated, except that bisphenol A (BPA) was used as the diol. 0.834 grams of IPA, 1.141 grams of BPA, and 0.074 grams of TBD were added with 125 ml of toluene. In this case as well, the mixture appeared clear after 15 minutes, and there were no suspended solids. When heating was stopped, precipitation was observed again. This was filtered off while still hot, and both the filtered hot solid and filtrate were dried. The filtered thermal product yielded 1.046 grams, compared to 1.039 grams in the second sample. This corresponds to a conversion of 15% of the diol. The DSC of the filtered thermal sample showed peaks at 288°C, 336°C, and 343°C. The published melting point of the BPA-IPA polymer is 270°C. IPA has a melting point of 343°C.

[0087] Equal portions While this disclosure has been described in conjunction with a detailed explanation, please understand that the above explanation is illustrative of the claims and not limiting them. Other aspects, advantages, and modifications are also within the scope of the claims.

[0088] This written description uses examples to disclose the present invention, including its best mode, and to enable those skilled in the art to carry out this embodiment, including the fabrication and use of any device or system, and the execution of any method incorporating it. The patentable scope of this embodiment is defined by the claims and may include other embodiments that a person skilled in the art could conceive. Such other embodiments shall be within the scope of the claims if they include structural elements that are not different from the language of the claims, or equivalent structural elements that are not substantially different from the language of the claims.

Claims

1. A method for producing a macrocyclic polyester oligomer, wherein the method comprises the step of reacting an aromatic dicarboxylic acid with a diol in the presence of a catalyst to form the macrocyclic polyester oligomer, the catalyst being a moisture-resistant catalyst.

2. A method for producing a polyester (e.g., polyarylate), the method comprising the step of reacting an aromatic dicarboxylic acid with a diol in the presence of a catalyst to form the polyester, wherein the catalyst is a moisture-resistant catalyst.

3. The method according to claim 1 or 2, wherein the catalyst comprises an organic base selected from the group consisting of triethylamine, N,N-diisopropylethylamine (DIPEA), N-methylmorpholine, diisopropylamine, 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), 4-dimethylaminopyridine (DMAP), pyridinium p-toluenesulfonate (PPTS), triazabicyclodecene (TBD), imidazole, and quaternary ammonium salts (e.g., hexadecyltrimethylammonium bromide).

4. The method according to claim 1 or 2, wherein the catalyst comprises triazabicyclodecene (TBD).

5. The method according to any one of the claims, wherein the catalyst is a heterogeneous catalyst (for example, a solid or deposited on a solid), and the method comprises the step of passing a solution containing the aromatic dicarboxylic acid and the diol over a catalyst bed (for example, the method is a continuous process).

6. The method according to any one of the claims, wherein the method comprises the step of reacting the aromatic dicarboxylic acid with the diol in a solvent solution, the solvent being selected from the group consisting of dichloromethane, tetrahydrofuran, toluene, xylene, and chlorobenzene.

7. The method according to any one of the claims, comprising the step of reacting the aromatic dicarboxylic acid with the diol in a solvent solution, wherein the aromatic dicarboxylic acid is present in the solution at a concentration of 0.02 to 0.3 molars and the diol is present in the solution at a concentration of 0.02 to 0.3 molars.

8. The method according to any one of the claims, wherein at least 60 wt.% of the aromatic dicarboxylic acid is isophthalic acid (IPA) (for example, the remainder, for example, 40 wt.% or less, is terephthalic acid (TPA).

9. The method according to any one of the claims, wherein the aromatic dicarboxylic acid is (i) isophthalic acid (IPA), or (ii) terephthalic acid (TPA), or (iii) a combination of IPA and TPA.

10. The method according to claim 2, wherein the polyester is a polyarylate, and the method further comprises the step of producing the macrocyclic polyester oligomer from the polyarylate by re-equilibrating the polyarylate (for example, in solution, in the presence of the catalyst) thereby producing the macrocyclic polyester oligomer.

11. The method of claim 2, wherein the polyester is a polyarylate (for example, a component made using the polyarylate, the component may also include a reinforcing filler or fibers), and the method further comprises the step of producing the macrocyclic polyester oligomer from the polyarylate by re-equilibrating the polyarylate (for example, in solution, in the presence of the catalyst) thereby producing a macrocyclic polyester oligomer (and, for example, recycling the component made using the polyarylate).

12. The method according to any one of the claims, further comprising the step of producing a composite containing at least 60 wt.% of a reinforcing material using the macrocyclic polyester oligomer or the polyester.

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