RU2799207C2 - Co-production of monomers, including at least one bio-based monomer - Google Patents

Abstract

FIELD: chemical industry.

SUBSTANCE: invention relates to method for obtaining a composition based on a mixture of monomers containing 2,5-furandicarboxylic acid (FDCA) and terephthalic acid (TPA). The method includes the dehydration of one or more six-carbon carbohydrates to obtain furan compounds forming FDCA, and the joint supply of these compounds and para-xylene to an oxygen oxidation reactor in the presence of an oxidation catalyst containing cobalt and (or) manganese compounds.

EFFECT: method for co-processing in the form of acid dehydration of renewable hexoses or hexosans to obtain 5-hydroxymethylfurfural (HMF), further co-catalytic oxidation of HMF and fossil raw materials in the form of p-xylene to obtain a composition of a mixture of monomers containing FDCA and TPA, reducing production energy costs in such joint processing, as well as reducing the poisoning of the catalytic system by side humins.

10 cl, 5 dwg, 2 tbl

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

The present invention relates, on the one hand, to methods for producing terephthalic acid (TPA) and to polymers that can be obtained from it. On the other hand, the present invention relates to processes for the preparation of the bio-based TPA analogue, 2,5-furandicarboxylic acid (FDCA), and to polymers that can be prepared from it.

BACKGROUND OF THE INVENTION

The depletion of fossil fuels has created strong incentives to find alternative sources to petroleum carbon for the synthesis of so-called "carrier" molecules that can serve as building blocks for commercially viable products. Biomass, from which many of these high-value chemicals can be derived, is currently being considered as a potential replacement, but developing sustainable technologies to produce such chemicals from renewable resources remains a major challenge.

Biobased monomers, 2,5-furandicarboxylic acid (FDCA) and its dimethyl ester derivative, 2,5-furandicarboxylic acid, dimethyl ester (FDME), are recognized as important starting materials for the production of copolymers of alkylene and furan and dicarboxylate , which can replace their well-known, mass-produced, petroleum-derived counterparts, namely alkylene-terephthalate copolymers such as polyethylene terephthalate (PET). A notable example of alkylene-furan-dicarboxylate copolymers is the ethylene-furan-dicarboxylate copolymer, or PEF, obtained from the reaction of FDCA or FDME with ethylene glycol. The bio-based polymer PEF (bioplastic) exhibits superior properties in many respects compared to its petroleum-derived PET counterpart, especially in the field of packaging. For example, blends of PEF and PET can provide improved carbon dioxide and oxygen barrier properties, extending shelf life compared to pure PET, and providing an acceptable container for products such as beer that are susceptible to oxidative degradation. Other packaging applications for PEF include films used to produce bags, wraps and shrink materials that have high mechanical strength and recyclability.

In general, FDCA and FDME are useful carrier molecules for the production of polyamides, polyurethanes, and polyesters, which have a variety of uses as plastics, fibers, coatings, adhesives, personal care products, and lubricants. The commercial importance of these molecules is evidenced, for example, by a 2004 US Department of Energy study that named FDCA one of twelve priority chemicals for creating a green chemical industry of the future. Due to its structural similarity to terephthalic acid (TPA), the potential of FDCA as a monomer substitute for polyester synthesis was recognized at least as early as 1946, for example in GB621971A, and significant efforts have been made by a number of parties for several years to achieve a commercially viable production method. FDCA. With regard to the synthesis of FDCA from biobased starting materials, advances are described in US 10538499, according to which the raw material containing a six-carbon sugar unit (for example, fructose) is subjected to complex processing stages, the first of which is the stage of providing dehydration to obtain 5-hydroxymethylfurfural ( HMF) or certain derivatives such as its ester or ether derivatives. The dehydration product is then oxidized to the required FDCA according to an oxidation similar to that used in the mid-century oxidation of p-xylene to produce TPA using a homogeneous catalyst system containing cobalt, manganese and bromine components. Despite these massive efforts, commercial production of FDCA has not yet been realized, and improved ways to synthesize FDCA and its derivatives on a biological basis are constantly being sought in an attempt to establish economic viability on a commercial scale.

SUMMARY OF THE INVENTION

Some aspects of the present invention relate to the discovery of ways to mitigate or even eliminate the harmful effects associated with the presence of at least some types of humins, which are highly colored and usually water-insoluble by-products of carbohydrate dehydration, in methods that use such carbohydrates as starting materials. materials for the synthesis of FDCA and its derivatives on a biological basis.

For example, at least some of the humins produced by the acid-catalyzed dehydration of carbohydrates having a six-carbon sugar unit (eg, hexose sugars and their oligomers and polymers) tend to consume mid-century homogeneous oxidation catalysts or limit their utility. These catalysts are most often proposed for the oxidation of 5-hydroxymethylfurfural (HMF) and/or its derivatives (eg ester and/or ester derivatives) which are formed during the dehydration process.

In general, it has been found that when these humins from the previous dehydration step are present in the oxidation feed along with HMF and/or its derivatives, performance can be limited with respect to the use of both homogeneous and heterogeneous catalysts. In a homogeneous catalyzed oxidation, this can manifest itself in (i) the need to increase the concentration of catalyst to maintain the desired conversion and yield profiles, and (ii) a narrower "work window" or set of conditions (temperature, pressure, time in the stream) under which a favorable performance before loss of response or "blackout" (eg based on the determination of oxygen consumption). In the heterogeneous catalyzed oxidation reactions that have been proposed from time to time for the oxidation of HMF and/or its derivatives to produce FDCA, these humins are also a problem because they can lead to catalyst deactivation as a result of their precipitation on catalyst solids.

In the face of these and other disadvantages associated with the oxidation of carbohydrate dehydration products having at least certain types of humins contained therein, it has been found that some types of associated raw materials unexpectedly have a beneficial stabilizing effect (for example, a reaction stabilizing effect) that counteracts workers. the restrictions noted above. This can result in partial or complete restoration of a useful or economically viable operating window that is otherwise limited by the presence of these humins. A stabilizing effect may be indicated by a wider range of possible operating conditions, including lower bounds on catalyst concentration, temperature and/or oxygen partial pressure required to achieve favorable activity, selectivity and/or stability (time in stream during which a desired performance level is maintained) . It is important to note that these co-feedstocks can be oxidized to other valuable monomers, similar to the oxidation of HMF and/or its derivatives to FDCA. Advantageously, the oxidation of both the stabilizing co-feedstocks and the HMF can be performed under the same conditions and hence the same reactor and catalyst system, whether homogeneous or heterogeneous, can be used. A related feedstock of particular interest is para-xylene, often derived from crude oil refining, which can be oxidized to terephthalic acid (TPA). Accordingly, some embodiments are directed to the co-production of monomers via oxidation, such as in the case of the co-production of FDCA and TPA.

In the specific context of co-oxidation using mid-century oxidation catalysts, processes for co-producing FDCA and TPA include co-feeding FDCA-forming furan compounds and para-xylene into an oxidation reactor containing a homogeneous mid-century oxidation catalyst and reactive oxygen, such that FDCA-forming furan compounds and para-xylene react effectively in the same medium, where para-xylene is used in sufficient quantity to impart a stabilizing effect (e.g., improve the performance of the reaction system in terms of its the ability to oxidize FDCA-forming furan compounds in the presence of at least certain types of humic by-products resulting from prior acid-catalyzed, especially mineral acid-catalyzed, dehydration of one or more carbohydrates (e.g., fructose) having a 6-carbon sugar unit), as described above. In representative methods, the prior dehydration of carbohydrates is combined with the oxidation of both (i) the dehydration product (e.g., containing HMF and/or derivatives thereof) that forms the first monomer, and (ii) the stabilizing agent (e.g., para-xylene) that forms second monomer.

Other aspects relate to the use of a co-feedstock in the oxidation of a carbohydrate dehydration product containing at least several humins, in which the co-feedstock partially or completely restores performance (e.g., catalyst activity) compared to a comparative (or baseline) process without co-feedstock, but with the same humins removed from the dehydration product or absent in it. Advantageously, performance recovery can be performed using only a small amount of co-feedstock (e.g., on a molar basis) relative to the carbohydrate dehydration product, based on the portion of it that oxidizes to the desired monomer (e.g., accompanying furan compounds forming FDCA).

In addition to the specific beneficial aspects provided by the co-oxidation process of the present invention with respect to the effect of humins in the carbohydrate dehydration product from which FDCA is to be obtained by oxidation, those skilled in the art of polyesters will appreciate other advantages provided by this co-oxidation process using existing, commercial methods or appropriate equipment used in the production of monomers by oxidation and/or corresponding polymers (e.g. polyesters such as PET) by combining such methods or equipment with a carbohydrate dehydration step or associated elements, including a dehydration reactor . The advantage of this retrofit is the ability to co-produce and co-process both conventional and bio-based monomers with only a fraction of the capital and time required to build a new stand-alone ("cleaner") bio-based polyester manufacturing plant. A particular type of retooling could include, for example, the installation of a fructose dehydration reactor and related equipment in an underused or temporarily decommissioned TPA plant. This may allow the co-feeding of HMF and/or its derivatives (e.g. ester or ester derivatives, depending on whether a carboxylic acid solvent or an alcohol solvent is used to produce a carbohydrate solution such as fructose that is dehydrated) with para- xylene. After the co-feedstock is oxidized, FDCA and TPA can be produced together in the oxidation product, i.e. in the form of a composition based on a mixture of monomers or a co-product.

Particular embodiments of the invention, taking into account these other advantages, are thus directed to methods for preparing a composition based on a mixture of monomers containing the first and second monomers, for example, 2,5-furandicarboxylic acid (FDCA), which may be a biobased monomer, and terephthalic acid (TPA), which can be, and usually is, a petroleum-based monomer, in more specific embodiments, using existing technical, physical and commercial assets and infrastructure associated with the production of the latter, to more easily commercialize the production of the former. The methods include bringing the oxidation feed, in the presence of oxygen (eg, in the presence of an oxygen-containing gas such as air), into contact with an oxidation catalyst to form a composition based on a mixture of monomers.

The oxidation feed comprises (i) a dehydration product of one or more carbohydrates (eg, fructose) having a 6-carbon sugar unit, and (ii) para-xylene.

The ability to oxidize in a single reactor under a common set of oxidation conditions for an oxidation feedstock consisting of both a dehydration product of one or more hexoses and para-xylene to a composition based on a mixture of monomers would be of significant value in the art, both in terms of use assets, as well as in other respects, such as providing funds to provide both conventional, non-renewable resource-based monomers and renewable resource-based monomers for the same market application in the relative proportions and quantities required by customers, without significant delays, and especially without the significant capital expenditures that so often hold back the development of new monomers and new polymers.

In this regard, the authors of the present invention found that a number of oxidation catalysts, including both homogeneous and heterogeneous catalysts, can be used in the co-oxidation process according to the present invention to obtain a composition based on a mixture of monomers containing both FDCA and TPA, in an addition to mid-century type oxidation catalysts that have been used commercially for many years to produce TPA (and in turn TPA esters).

In the context of retrofitting the application just mentioned, or generally in connection with realizing the stabilization benefits mentioned previously, the dehydration and oxidation steps may optionally be combined with a number of additional steps which include color stabilization, derivatization (e.g. providing esterification), separating and obtaining a polymer. The step of obtaining the polymer may (in relation to the production of polyesters and copolyesters) itself include sub-steps (i) providing esterification or transesterification and (ii) polymerization by polycondensation. These steps and sub-steps can be carried out in accordance with a number of different process configurations, the choice of which will be apparent to one skilled in the art familiar with the present invention, and taking into account the particular types of raw materials being processed and the desired end products.

One particular embodiment, for example, may include processing the monomer mixture composition into fractions enriched in various monomers (for example, and ideally essentially free of the monomers in which they are depleted), for example, into a first fraction enriched in FDCA and a second fraction, enriched with TPA. Either or both of these cuts can then be subjected to color stabilization, for example by hydrogenation of color-producing aldehyde by-products (for example, 5-formyl-2-furoic acid (FFCA), which may be present in the enriched FDCA cut, and/or 4-carboxybenzaldehyde (4-CBA) which may be present in the enriched TPA fraction) or other recovery/purification steps prior to use in the subsequent polymer step. Another particular embodiment may involve the use of recovery/purification steps without fractionating the monomer mixture composition, for example by subjecting the entire monomer mixture composition to color stabilization, for example by hydrogenating both FFCA and 4-CBA in the same process. flow. The resulting stabilized composition (or composition based on a mixture of monomers) can then be separated into a stabilized first fraction (for example, a stabilized fraction enriched in FDCA) and a stabilized second fraction (for example, a stabilized fraction enriched in TPA), with subsequent use of these fractions in separate stages obtaining a polymer. In this way, separate copolymers can be prepared, for example one having furandicarboxylate moieties and preferably substantially free (or at least containing less) benzene dicarboxylate moieties (e.g. in the case of PEF) and another having benzene dicarboxylate (or terephthalate) moieties. and preferably substantially free of (or at least containing a smaller amount of) furandicarboxylate moieties (eg in the case of PET). Alternatively, the stabilized composition (e.g. containing FDCA and TPA oxidation products) can be used directly (e.g. without separation) in a subsequent polymer production step, e.g. to make a copolyester with one or more alcohols/polyols (e.g. ethylene glycol), such as a copolymer containing both furandicarboxylate moieties and benzene dicarboxylate moieties.

Other aspects relate to the further subsequent polymerization of one or both of these monomers or their derivatives, such as furanoate esters and terephthalate esters, to obtain polyesters either separately or together. In the first case (polymerization alone), these monomers can be separated as they are by oxidation, or they can be manipulated to facilitate their separation, for example, by forming convenient derivatives of the monomers (for example, conveniently the same (ester) derivatives , which are intended to polymerize) that are easier or more economical to separate due to the fact that they have lower boiling points and / or a large relative difference in volatility compared to their under-oxidized form. For example, furanoate ether and terephthalate ester should be easily separated by distillation. In the latter case (copolymerization), a copolymer can be obtained containing, for example, both FDCA-related moieties and TPA-related moieties.

If the subsequent polymerization concerns the formation of one or more homopolyesters or copolyesters from one or more monomers or their derivatives, either alone or in one or more combinations with each other and optionally with other comonomers or oligomers, then such FDCA-related moieties may be furandicarboxylate moieties, and such TPA-related moieties may be terephthalate moieties (or benzene dicarboxylate moieties) obtained by polycondensation after reacting FDCA and/or TPA, or alternatively, ester derivatives of FDCA and/or TPA, with a comonomer having at least two hydroxyl groups (eg diol).

In other embodiments, the subsequent step of making the polymer may include reacting, as a comonomer, a hydroxyl (alcohol) derivative of one or both of FDCA and TPA (e.g., a diol derivative of one or both of FDCA and TPA), alone or in combination, with a polyacid or its ester derivative to give a polyester having one or both of the FDCA-related moieties and the TPA-related moieties.

If the subsequent polymerization concerns the formation of one or more polyamides or copolyamides from one or more monomers or their derivatives, either alone or in one or more combinations with each other and optionally with other comonomers or oligomers, then in some embodiments, one or both of FDCA and TPA, alone or in combination, may be reacted with a comonomer having at least two amino groups (eg, a diamine) to form a polyamide having one or both of the FDCA-related moieties and the TPA-related moieties.

In additional embodiments, the subsequent step of making the polymer may include reacting, as comonomer, a hydroxyl (alcohol) derivative of one or both of FDCA and TPA (e.g., a diol derivative of one or both of FDCA and TPA), alone or in combination, with a polyisocyanate to obtain a polyurethane having one or both of the FDCA-related moieties and the TPA-related moieties.

In additional embodiments, the subsequent step of making the polymer may include reacting, as a comonomer, an amine derivative of one or both of FDCA and TPA (e.g., a diamine derivative of one or both of FDCA and TPA), alone or in combination, with a polyacid to form a polyamide. having one or both of FDCA-related fragments and TPA-related fragments.

In additional embodiments, the subsequent step of making the polymer may include reacting an acyl derivative of one or both of FDCA and TPA (e.g., a diacyl chloride derivative of one or both of FDCA and TPA), alone or in combination, with a comonomer having at least two amino groups (e.g. , diamine) to produce a polyamide having one or both of the FDCA-related moieties and the TPA-related moieties.

In additional embodiments, the subsequent step of making the polymer may include reacting an isocyanate derivative of one or both of FDCA and TPA (e.g., a diisocyanate derivative of one or both of FDCA and TPA), alone or in combination, with a comonomer having at least two hydroxyl groups ( eg diol) to form a polyurethane having one or both of the FDCA-related moieties and the TPA-related moieties.

Those skilled in the art familiar with the present invention will appreciate from the foregoing that the co-oxidation of FDCA and TPA precursors to produce the commercially desired FDCA and TPA monomers (and hence their various known derivatives) allows for a very significant number of desirable downstream polymer scenarios to be considered. one or both of FDCA and TPA, of which the embodiments described above are only an illustrative part.

Other embodiments are directed to methods for modifying a TPA plant, providing an oxidation reactor adapted to produce para-xylene and oxygen (or oxygen-containing gas) as feedstocks, as well as a downstream terephthalic acid crystallization and reduction section configured to separating the solvent from the TPA and recycling it to the oxidation reactor. The methods include retrofitting a terephthalic acid plant by connecting from an existing oxidation reactor inlet or an added oxidation reactor inlet to an upstream carbohydrate dehydration reactor.

In yet another aspect, the present invention relates to the discovery that para-xylene can be used as a co-solvent, for example for FDCA furan precursors, in an upstream carbohydrate dehydration reactor previously co-oxidized from the dehydration product of one or more hexoses and para -xylene to form a composition based on a mixture of monomers, where, for example, in the retooling scenario just given, there is a connection from the inlet of an existing oxidation reactor for converting para-xylene to TPA to such a downstream reactor for dehydration of carbohydrates. Therefore, in some embodiments, at least a portion of the para-xylene to be oxidized to form a corresponding portion of the monomer blend composition may be introduced via the product blend from an upstream carbohydrate dehydration reactor along with one or more furan compounds forming FDCA. formed in it.

Introducing at least a portion of the para-xylene to be oxidized in this way allows some significant advantages to be realized. For example, if hydrobromic acid is used in a dehydration process in addition to acetic acid, and is combined with a subsequent mid-century oxidation stage such that the dehydration product is fed directly to the subsequent oxidation stage as described in US 10538499, then at least a portion para-xylene can actually displace a significant amount of acetic acid, which is considered in US 10538499 to be optimally recovered and recycled after the oxidation step, so that the capital and operating costs associated with this recycling can be reduced. Moreover, the amount of thermal energy generated in the co-oxidation stage, compared to the amount of acetic acid that must be recycled in the integrated process carried out in accordance with US 10538499, is significantly increased, which makes it possible to at least partially offset the energy costs associated with stream of recycled acetic acid. Therefore, in some embodiments of the method according to the present invention, where the stage of providing dehydration of carbohydrates is combined with a subsequent stage of oxidation to obtain a composition based on a mixture of monomers containing FDCA and terephthalic acid, the amount of para-xylene supplied to the oxidation stage from the previous stage of providing dehydration, may significantly exceed the amount that would be stated to provide a stabilizing effect or benefit as described previously, taking into account what humins are present in the materials supplied to the oxidation stage - for example, in some embodiments, up to 20 weight percent of that part of the raw material for obtaining a composition based on a mixture of monomers in a subsequent stage of oxidation (especially using oxidation of the type of oxidation of the middle of the last century, but optionally using a different oxidation catalyst, as shown below), which is obtained at the stage of providing dehydration of carbohydrates, can be para-xylene.

All of these and other aspects, embodiments and associated advantages will become apparent from the following detailed description.

BRIEF DESCRIPTION OF GRAPHICS

A more complete understanding of exemplary embodiments of the present invention and its advantages can be obtained by referring to the following description, taking into account the accompanying figures.

In FIG. 1 shows a multi-stage process for producing a copolymer by preparing a composition based on a mixture of monomers and using it in the polymer production step.

In FIG. 2 shows a multi-step process in which the monomer mixture composition is fractionated prior to using one or both of the fractions in the polymer production step.

In FIG. 3 shows the use of a carbohydrate dehydration reactor for retrofitting a terephthalic acid plant.

In FIG. 4 is a table of experimental results related to the examples below.

In FIG. 5 provides a second table of experimental results related to the examples below.

In FIG. 1-3, the same reference numerals and other reference symbols are used to denote the same or similar features. These figures are to be understood as simplified overviews of the methods and associated equipment to demonstrate certain principles. The elements depicted are not necessarily drawn to scale; also, the illustrated methods and associated equipment do not preclude the addition of any preceding, intermediate, or subsequent steps, such as separation, combining, and/or reaction steps. For example, an intermediate processing step may include both separation and pooling. As will be appreciated by one of ordinary skill in the art familiar with the present invention, other methods may have alternative configurations and/or components that are governed by particular operational purposes, but these alternatives are nonetheless within the scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS

Some aspects of the invention relate to processes in which a dehydration product, such as a hexose (e.g., fructose) carbohydrate dehydration product, is oxidized in the presence of a "co-feed" that can be considered a "stabilizing co-feed" to the extent that it provides or may provide the benefits of stabilizing the oxidation reaction as described herein. This co-feed can be oxidized to provide a useful product, such as a second monomer, which is different from the monomer obtained from the oxidation of the dehydration product. Accordingly, such a "co-feed" or "stabilizing co-feed" may also be characterized in such cases as a "second monomer-forming co-feed". In any of these designations, the term "co-feed" should not be construed as imposing any limitation on the amount of addition or presence relative to the amount of the dehydration product or any part thereof, for example, part of the accompanying furan compounds forming FDCA, which is oxidized to the desired monomer such as FDCA. Accordingly, specific embodiments described herein are directed to adding co-feedstock in a substoichiometric amount, or at a molar ratio less than 1, relative to the moles of FDCA-forming furan compounds, while other embodiments are directed to adding it in an excess stoichiometric amount, or at molar ratio greater than 1. The latter case may arise, for example, in the case of retrofitting an existing plant (plant) used for the oxidation of p-xylene to produce TPA, with a relatively small addition of the dehydration product as a source of bioderivative monomer, as may be required, for example, in the early stages of FDCA commercialization.

The terms "wt.%" and "wt. ppm", used in this document, are used to refer to percent by weight and parts per million by weight, respectively. The term "mole %" is used to refer to mole percent. Unless otherwise indicated, the phrase "not containing (or containing) in essence" can mean, in various embodiments, "having (or having) less than 5 wt.%", "having (or having) less than 3 wt.%" or "having (or has) less than 1 wt.%". When referring to "by-products" such as humic by-products and color-forming by-products, they may alternatively be referred to as "contaminants" or "impurities".

This document describes methods for producing 2,5-furandicarboxylic acid (FDCA) in combination with other monomers such as terephthalic acid (TRA). Some processes explicitly include steps to "provide esterification" to produce ester derivatives of FDCA and TPA, where one or preferably both of the carboxylic acid groups of these dicarboxylic acids are ester groups such as alkyl ester groups (in the case of a mono- or dialkyl ester derivative) or ester groups. aryl ether groups (in the case of a mono- or diaryl ether derivative), with methyl ether groups, ethyl ester groups or phenyl ether groups being specific examples. In the case of methyl ester groups, the preferred FDCA ester derivative is 2,5-furandicarboxylic acid, dimethyl ether (FDME), and the corresponding preferred TPA ester derivative is dimethyl terephthalate (DMT), which can be formed by reacting FDCA and TPA, respectively, with sufficient the amount of methanol.

Those skilled in the art with knowledge of the present invention will appreciate that the methods described herein can also be used to produce a wide range of other FDCA and TPA derivatives, including, without limitation, ester derivatives other than FDME and DMT, in addition to hydroxyl (alcohol) derivatives which include hydroxyalkyl derivatives; ether derivatives, which include alkoxy derivatives; amino derivatives; acyl derivatives, which include acyl halide derivatives such as acyl chloride derivatives; isocyanate derivative; aldehyde derivatives and acetal derivatives. In the case of such derivatives, one or both of the two carboxy-substituted FDCA furan ring members or one or both of the two TPA benzene ring carboxy-substituted members may be substituted with carboxylic acid groups other than carboxy and/or these other groups, to give, for example, the corresponding diol, dialkanol (e.g. dimethanol), diamino, diacyl (e.g. diacyl chloride), diester, diisocyanate, derivatives in the form of an ether-acid complex, an ether-ester complex, an ester-acid complex, an ester- aldehyde, ether-aldehyde complex, ether-acetal complex, ester-acetal complex, acetal-acid complex, hydroxyl-acid complex, hydroxyalkyl-acid complex, hydroxyl-ester complex, hydroxyalkyl-ester complex, hydroxyl- an acetal, a hydroxyalkyl-acetal complex, a hydroxyalkyl-hydroxyalkyl complex, a diacetal and/or an aldehyde-acetal complex, wherein the "acid" substituent refers to a carboxy or a radical, such as carboxymethyl, formed from a carboxylic acid other than acetic acid.

In this regard, as will be explained in more detail below, the formation of these various derivatives from the exemplary FDCA and TPA monomers may be required in relation to the composition based on a mixture of monomers to facilitate the separation of the composition based on a mixture of monomers into a fraction rich in FDCA and preferably essentially completely depleted in TPA. , on the one hand, and a fraction rich in TPA and preferably essentially completely depleted in FDCA, on the other hand, and in general to solve the problem of the tendency of any aldehyde-containing species resulting from oxidation to undergo aldol condensation and develop color over time in the composition based on mixtures of monomers or in enriched monomer fractions containing these aldehyde-containing species. Ester derivatives are particularly suited to achieve these goals in the context of making homopolyester and copolyester polymers, in which TPA and FDCA are expected to be most commonly used commercially, but those skilled in the art of polymerization can of course imagine other FDCA derivatives and TPAs that can be used in the subsequent step of polymer formation, and the relative advantages and disadvantages of these various possible derivatives in the context of obtaining the desired polymer product or combination of polymer products.

In the case of ester derivatives of esters, like their parent carboxylic acids (eg, dicarboxylic acids), they can be used as monomers in the polymerization steps as described herein. Therefore, any such ester derivative may be equivalently referred to as "monomer ester derivative"; in accordance with the previous paragraph, however, the fact that in the following we will consider and describe predominantly "ester" derivatives and the "exercise of esterification" of diacids FDCA and TPA should not be taken as implying that other derivatives, as just described, cannot also be used as monomers in downstream polymer formation steps, but rather as only reflecting the expectation that co-produced FDCA and TPA will be most commonly targeted for use in the production of polyester products. Therefore, any subsequent reference to "ester derivatives" or "esterification" will be understood to include any other form of derivative or derivatization of FDCA and/or TPA, unless those skilled in the art understand in the context that only ester derivatives or esterification can reasonably be contemplated. .

In particular, the present document discloses methods for preparing a composition based on a mixture of monomers containing FDCA and TPA, using an oxidation step that forms both of these monomers. The methods include contacting a feedstock for oxidation in the presence of oxygen (eg, an oxygenated feedstock such as air) with an oxidation catalyst to form a composition based on a mixture of monomers. The oxidation feed may comprise (i) a dehydration product of one or more carbohydrates (eg, fructose) having a 6-carbon sugar unit, and (ii) para-xylene. Thus, component (i) of the oxidation feed may include FDCA-forming furan compounds, and representative methods may include feeding both components (i) and (ii) to an oxidation reactor containing an oxidation catalyst (e.g., a homogeneous or heterogeneous catalyst) and reactive oxygen.

A carbohydrate with a six-carbon sugar unit means a six-carbon sugar, a six-carbon sugar oligomer, or a six-carbon sugar polymer. Such carbohydrates include starch, amylose, galactose, cellulose, hemicellulose, inulin, fructan, glucose, fructose, sucrose, maltose, cellobiose, lactose, and sugar oligomers. These carbohydrates may also be referred to as hexose carbohydrates and may be derived from one or a combination of products, by-products or intermediates of the wet or dry grain milling process, such products including one or more of fructose syrup, crystalline fructose, high fructose corn syrup, crude fructose, refined fructose or molasses.

The preferred carbohydrate is fructose, which can be provided in the dehydration step in pure or purified form (eg greater than 90% or 95% pure).

Furan compounds forming FDCA refer to monomeric and dimeric molecules containing a furan ring that form FDCA by catalytic oxidation as described herein. FDCA-forming furan compounds, along with unwanted by-products (e.g., humins), can be obtained as a dehydration product by dehydrating one or more carbohydrates having a six-carbon sugar unit at elevated temperature and in the presence of an acid catalyst, which can be homogeneous or heterogeneous in nature. Furan compounds that form FDCA include 5-(hydroxymethyl)furfural (HMF) and, when prepared in the presence of a lower carboxylic acid (i.e., a C ₁ -C ₆ aliphatic carboxylic acid such as acetic acid), can include ester derivatives of HMF, such as 5-(acetoxymethyl)furfural, or, when formed in the presence of a lower alcohol solvent (i.e. C ₁ -C ₆ aliphatic alcohol, such as methanol), may include ester derivatives of HMF, such as 5-(methoxymethyl)furfural. Other FDCA-forming furan compounds may include HMF derivatives such as 2,5-diformylfuran and 5-formyl-2-furancarboxylic acid. Furan compounds forming FDCA also include the HMF dimer 5,5'-[oxybis(methylene)]di(2-furaldehyde) as well as HMF oligomers. Examples of furan compounds that do not form FDCA include, without limitation, furfural, 2-(hydroxyacetyl)furan, and 2-(acetoxyacetyl)furan. In preferred embodiments, the dehydration product may include such that the FDCA-forming furan compounds may include one or more of HMF and/or an ester or ester derivative thereof. In the case of dehydration using an acetic acid catalyst and a solvent, the FDCA-forming furan compounds may include HMF, 5-(acetoxymethyl)furfural, and HMF dimer. In one embodiment, as described in more detail below, hydrobromic acid is used in the dehydration in addition to acetic acid, and is combined with a subsequent mid-century type oxidation step such that the dehydration product is fed directly to the next oxidation step in accordance with US 10538499 , except that a stabilizing co-feedstock is also fed to the next oxidation stage. As used herein, HMF ester derivatives should be understood to mean compounds that are or are obtained by esterification of the hydroxyl group of HMF with a carboxylic acid via a condensation reaction, for example, the condensation of acetic acid and the hydroxyl group of HMF to give 5-(acetoxymethyl)furfural. As used herein, HMF ester derivatives should be understood to mean compounds which are or are obtained by esterification of the hydroxyl group of HMF, for example, esterification of the hydroxyl group of HMF under methylation conditions to give 5-(methoxymethyl)furfural.

According to processes in which the oxidation feedstock contains a dehydration product, such as a product containing FDCA-forming furan compounds, at least two processing steps can be performed, namely (i) dehydration of the six-carbon sugar carbohydrate to obtain a dehydration product, containing compounds of the furan series, forming FDCA, and (ii) the oxidation of the dehydration product in the raw material for oxidation, further comprising para-xylene, to obtain FDCA together with TPA. Such steps can be integrated as described above, providing advantages that may include the use of the same acetic acid solvent (or acetic acid and water) in both steps. Moreover, the use of a conventional solvent, in addition to the suitability of hydrobromic acid for use as an additional acid catalyst in the dehydration step, provides the additional advantage that acetic acid and optionally at least a portion of the bromine source for the mid-century oxidation step (generally in the form of hydrobromic acid) can be recycled (and preferably substantially recycled) from the oxidation stage back to the dehydration stage. This results in a significant reduction in capital and operating costs associated with the conversion of a carbohydrate with a six-carbon sugar unit to FDCA. In addition, an integrated process can be obtained by retrofitting existing equipment used in such oxidation reactions, for example, in the oxidation of p-xylene to produce TPA.

The oxidation step can be carried out by adding a co-feed, such as para-xylene, which imparts or may impart a stabilizing effect on the reaction as described above, the latter scenario being envisaged when the dehydration product is not supplied directly and without any intermediate further processing. to the oxidation step, such intermediate treatment, for example, in the form of processing or purification to remove humins from the dehydration product as a whole, or in the form of some pre-treatment of humins in the dehydration product to mitigate or at least partially mitigate the harmful effects of at least the same types of humins in it, on which the accompanying raw material has a stabilizing effect on the reaction.

Advantageously, this reaction stabilizing effect can be realized with a relatively small amount of co-feedstock (if appropriate and required given the manufacturer's desired product blend in a monomer blend formulation containing FDCA and a second monomer such as TPA) which, is known to also serve as a source of the second monomer. In some embodiments, the effect of stabilizing the reaction can be realized by adding accompanying raw materials (for example, batchwise or continuously into the oxidation reactor) in an amount of less than 50 mol. %, based on the number of moles (for example, based on the total number of moles of HMF, 5-(acetoxymethyl)furfural and HMF dimer) of oxidizable furan compounds forming FDCA. For example, the accompanying raw material may be added in a substoichiometric (submolar) amount of less than 45 mol. % (for example, from 5 mol. % to 45 mol. %) of furan compounds forming FDCA. In other embodiments, the associated feedstock (eg, para-xylene) may be added in a sub-stoichiometric amount of less than 80 mol. % (for example, from 10 mol.% to 80 mol.% or from 30 mol.% to 60 mol.%) of furan compounds forming FDCA.

However, as mentioned above, in other embodiments, it is required to add a larger amount, such as a stoichiometric equivalent (molar equivalent) amount or an excess stoichiometric (molar excess) amount, of the accompanying feed, for example, to obtain a second monomer in a larger ratio to the first monomer, as well as to provide the effect of stabilizing the reaction to produce the first monomer, and the method of the present invention has the flexibility to implement this scenario.

For example, related raw materials can be added in an amount representing more than 85 mol. % (for example, from 85 mol.% to 200 mol.%), more than 90 mol. % (for example, from 90 mol.% to 150 mol.%) or more than 100 mol. % (for example, from 100 mol. % to 125 mol. %) of furan compounds forming FDCA. In specific embodiments in which an excess stoichiometric amount of the accompanying feedstock is added, this may be an amount representing greater than 125 mol. % (for example, from 125 mol.% to 1000 mol.%), more than 150 mol. % (for example, from 150 mol.% to 500 mol.%) or more than 200 mol. % (for example, from 200 mol.% to 400 mol.% or from 300 mol.% to 400 mol.%) of furan compounds forming FDCA.

Expressed in terms of weight rather than mole ratio, in some embodiments, an oxidation feedstock containing (i) a dehydration product of one or more carbohydrates (e.g., with a six-carbon sugar unit) and (ii) a second monomer-forming co-feedstock (e.g., para -xylene), the latter may represent at least 1 wt.% of the total amount of (i) and (ii). For example, the associated raw material may be present in an amount of 1 wt.% to 75 wt.%, 2 wt.% to 45 wt.%, or 5 wt.% to 35 wt.% of the total amount of (i) and ( ii).

In the case of co-feeding (i) FDCA-forming furan compounds and (ii) para-xylene into an oxidation reactor containing an oxidation catalyst and reactive oxygen to form a monomer mixture composition containing the first and second monomers (e.g., FDCA and TPA), these feeds (i) and (ii) can be provided as separate streams (eg introduced at different locations) to the same oxidation reactor. For example, the separate streams can provide a greater degree of desired temperature profile in the oxidation reactor or otherwise provide improved control over this temperature profile, such as through positioning or manipulation of exothermic heat generation. Alternatively, feeds (i) and (ii) can be provided as a combined feed stream to the oxidation reactor, for example by combining a para-xylene stream with a dehydration reactor effluent containing FDCA-forming furan compounds. In further embodiments, portions of feedstocks (i) and (ii) may be combined before being introduced into the oxidation reactor and/or added as separate streams to the oxidation reactor, depending on process efficiency and process control goals. As described above, co-feeding can be further combined, in an integrated or non-integrated manner, with a further step to co-feeding one or more carbohydrates for dehydration to form FDCA-forming furan compounds. Such dehydration can be carried out when one or more carbohydrates (eg selected from hexose sugars) are in solution containing a lower carboxylic acid (eg acetic acid) or a lower alcohol (eg methanol or ethanol) as a solvent.

As described above, specific embodiments of the present invention are directed to processing options as well as the overall processing flexibility that comes with using a second monomer-forming co-feedstock. Particular embodiments relate to processing steps after the steps of providing dehydration and oxidation to obtain a composition containing two monomers, or a composition based on a mixture of monomers. The steps for providing dehydration and oxidation are described below, as well as additional and optional steps for removing or modifying problematic humin species, color stabilization, providing esterification (or derivatization by other means, in general), separation, and polymerization, which can be performed in a different order and in accordance with the various configurations described, with further reference to the specific orders and configurations shown in the figures. Those familiar with the present invention, one skilled in the art will easily imagine other methods having these additional steps, optionally with additional steps that are nonetheless within the scope of the present invention.

Dehydration of Carbohydrates to Obtain Furan Compounds Forming FDCA

Representative processes include a dehydrogenation step prior to the oxidation step to produce FDCA-forming furan compounds as described above, all or part of which is used in this oxidation step (eg, as a component of an oxidation feed or co-feed stream). The dehydration step may be performed batchwise, wherein the FDCA-forming furan compounds are reduced and periodically transferred to the oxidation step, but preferably the dehydration step is performed continuously with continuous transfer. In any case, the preceding step of the process may include providing for the dehydration of a dehydration feed containing one or more carbohydrates having a six-carbon sugar unit, as described above. This dehydration feedstock (e.g., aqueous fructose) may have a dry matter concentration of 5 wt.% to 50 wt.%, for example, from 10 wt.% to 30 wt.% and / or can be obtained from a purified source of six-carbon sugar, such as fructose having a purity of at least 90 wt.% (for example, 97 wt.% fructose). The dehydrogenation can take place in the presence of a source of bromine and a solvent for FDCA-forming furan compounds, and can be carried out at an elevated temperature and for a time sufficient to provide an oxidation feed containing FDCA-forming furan compounds such as HMF and/or its derivatives. Depending on the solvent, the derivative(s) may include an ester derivative, an ester derivative and/or an HMF dimer. The oxidation feed containing as a component part or all of the product obtained from the dehydration step (dehydration product) usually also contains at least a portion of the solvent. That is, all or part of the solvent, such as a mixture of acetic acid and water, that is used in the dehydration step may be transferred to the oxidation step, in addition to all or part of any water generated in that step. In other cases, the solvent may include an alcohol such as methanol, ethanol or a higher alcohol, or possibly a cyclic or heterocyclic hydrocarbon compound (eg dioxane). The solvent is preferably separated after the oxidation step to provide, in addition to the monomer mixture or co-product composition as described herein, the solvent recycle stream to be returned to the dehydration step. The solvent recycle stream may contain FDCA-forming furan compounds, so that the total amount of FDCA-forming furan compounds in the dehydration product may include a portion that was newly formed during the dehydration enabling step (i.e., on a "conversion per pass" basis). ), and the part that was recycled back from the subsequent oxidation step.

In some advantageous embodiments, the solvent used in the dehydration step may be or may contain all or part of an associated feedstock such as para-xylene. In such embodiments, all or part of the co-feedstock added to the subsequent oxidation step may be present in the dehydration product along with the FDCA-forming furan compounds. In the case where part of the co-feedstock is present, the second part can be added directly at the stage of oxidation (for example, in the oxidation reactor), while a fresh make-up part of the co-feedstock can be added directly at the stage of providing dehydration (for example, in the dehydration reactor) or otherwise to a solvent recycle that is separated from the effluent from the oxidation stage (eg, from the oxidation reactor) and fed back to the stage for providing dehydration (eg, to the dehydration reactor). Accordingly, the portion of co-feedstock present in the dehydration product may be the combined amount of the fresh make-up portion and the amount present in the solvent recycle (eg, during stationary operation). If at least a portion of the accompanying feedstock is added to the dehydration step for use as a solvent, the total material requirement and cost associated with using a conventional solvent or component (e.g., acetic acid) that does not oxidize to form a second monomer or oxidation in general are beneficially reduced or even completely eliminated. To the extent that the co-feedstock added to the dehydration step serves as an effective solvent for the FDCA-forming furan compounds and also oxidizes to the second monomer of the composition based on the mixture of monomers obtained downstream from the oxidation step, those skilled in the art, Those familiar with the present invention will appreciate that a number of operational advantages result. For example, solvent recycling work responsibilities and associated costs can be reduced or even eliminated entirely. In addition, the productivity of the oxidation stage can be significantly increased, for example, based on the molar production rate of one or more monomers (eg, one of both FDCA and TPA) per unit volume of the oxidation reactor.

The source of bromine used in the dehydration step may be any compound that provides for the formation of bromide ions or radicals in the reaction mixture. Representative sources of bromine include hydrogen bromide, bromic acid, sodium bromide, potassium bromide, molecular bromine, benzyl bromide, and tetrabromoethane. If hydrogen bromide is used, this compound, in the presence of a dehydration feedstock and a solvent, can act as an acid catalyst in the dehydration step to form bromic acid upon dissociation. In some other embodiments, bromine sources such as 1-alkylpyridinium bromides and 1,3-dialkylimidazolium bromides may be useful as promoters in the presence of a solvent containing acetic acid and water.

Thus, the dehydration step produces a dehydration product, some or all of which can be used as a component of the subsequent oxidation step, along with a stabilizing co-feed as described herein, used to produce the second monomer. Specific dehydration processes are described, for example, in US 10538499 where both hydrobromic acid and acetic acid are provided to dehydrate especially fructose and are then fed for use in a subsequent mid century type oxidation step.

Removal of humins from the dehydration product

As described above, the dehydration step may result in the formation of humins as by-products in the dehydration product containing FDCA-forming furan compounds. Humins are highly colored, usually brown to black, amorphous or non-crystalline polymers formed from the dehydration of sugars. The concentration of humins in the dehydration product will depend at least in part on the conditions and, in particular, on the intensity of the reaction used in the stage of providing dehydration, so this concentration can be correlated with the conversion per pass.

Since humins are generally considered detrimental to the subsequent oxidation step, as well as undesirable in terms of their ability to color the final biobased polymer product, representative methods may further include the step of separating at least a portion of the humins from the dehydration product prior to the oxidation step (e.g., with obtaining raw materials for oxidation with a reduced concentration of humins compared to the dehydration product). However, as described above, the effect of stabilizing the reaction by using para-xylene or other second monomer-forming co-feedstock with the dehydration product can reduce or even eliminate the need to remove humin before the oxidation step. Therefore, in some embodiments, the dehydration product is not treated to remove humins prior to the oxidation step. For example, in particular embodiments, the humic content of the FDCA-forming furan compounds produced in the dehydration step is not reduced by filtration or other suitable means of separating at least a portion of the humins from the dehydration product prior to co-feeding the dehydration product with para-xylene to oxidation reactor. In other embodiments, however, a purified portion of the dehydration product as described herein, which includes purified HMF and/or other FDCA-forming furan compounds, and which is obtained after removal (e.g., ultrafiltration) of the contaminating humin-enriched portion of the dehydration product , however, may benefit from the addition of co-feedstock (e.g., para-xylene) in terms of mitigating reaction instability occurring under oxidizing conditions, and further in retrofit scenarios to take advantage of para-xylene's underutilized oxidative capacity.

In accordance with specific embodiments, representative methods include removing at least a portion of the humins in the dehydration product before (before) the oxidation step (eg, to provide feedstock for oxidation). If it is necessary to remove humins, the dehydration product can be subjected to filtration, for example using an ultrafiltration (UF) membrane, taking advantage of the general insolubility of humins in water. Other methods for removing humins from the dehydration product or from other intermediates in the overall bio-based polymer synthesis include distillation and sublimation. Specific methods for removing humins are described, for example, in US 10457657.

Oxidation of the oxidation feedstock to obtain an accompanying product containing comonomer

Representative methods include contacting an oxygen oxidation feedstock with an oxidation catalyst to form a composition based on a mixture of monomers or an accompanying product as described herein, which may contain FDCA and a second monomer formed using an accompanying feedstock such as para- xylene, as the second component of the raw material for oxidation. All or part of the dehydration product (eg, containing FDCA-forming furan compounds) can be used as the first component of the oxidation feed, for example, the part obtained after the removal of humins as described above. The oxidation feed may further comprise all or part of the solvent used to produce the dehydration feed and/or at least one bromine-containing species. Oxygen can be obtained using air, purified oxygen, or other oxygen-containing feedstock as a source. The oxidation step may be performed batchwise, but preferably performed continuously, wherein at least the dehydration product (or a portion thereof), the associated feedstock, and the oxygenated feedstock, and optionally the catalyst, are continuously fed into the oxidation reactor and the composition based on the mixture of monomers is continuously withdrawn from this reactor. .

Specific methods may include bringing the oxidation feed as described above into contact with a metal containing catalyst and an oxygen containing feed at an elevated temperature for a time sufficient to obtain as an oxidation product a composition based on a mixture of monomers containing FDCA and/or its derivatives, the second a monomer resulting from the oxidation of a co-feedstock (eg, TPA formed from the oxidation of para-xylene), a solvent, and a residual catalyst. The at least one bromine-containing species in the oxidation feed may provide some or substantially all of the bromine required for the oxidation step. Representative bromine species include inorganic bromides such as HBr; metal bromides such as lithium bromide, sodium bromide, potassium bromide, magnesium bromide, calcium bromide, cobalt bromide and manganese bromide; and organic bromides such as 5-(bromomethyl)furfural and its derivatives, and brominated furan oligomers. A source of bromine may be introduced into the oxidation stage (eg fed into the oxidation reactor) if necessary to supplement the bromine content provided by bromine-containing species in the oxidation feed that originate from the dehydration supply stage.

In the case of homogeneous (liquid-phase) oxidation catalysts, metal-containing catalysts, in particular, can be effective in converting HMF and/or other FDCA-forming furan compounds (e.g., HMF esters and/or HMF ethers) into oxidation feedstock ( depending on the solvent used in the dehydration step), to FDCA and/or its derivatives. Representative metal catalysts may include one or more transition metals, for example one or both of Co and Mn, optionally in combination with Zr or Ce. The metal-containing catalyst may react with bromine present in the bromine-containing species as described above to form metal bromides in situ. According to specific embodiments, the metal catalyst may be present in the reaction mixture in the oxidation reactor such that the concentrations of one or more transition metals are independently in the range of 5 wt. ppm up to 10000 wt. ppm, for example from 10 wt. ppm up to 8000 wt. ppm or from 50 wt. ppm up to 5000 wt. ppm. For example, Co may be present in the reaction mixture at a concentration of 10 wt. ppm up to 10000 wt. ppm, from 10 wt. ppm up to 8000 wt. ppm, from 59 wt. ppm up to 5900 wt. ppm or from 2000 to 4000 wt. ppm Mn may be present in the reaction mixture at a concentration of 5 wt. ppm up to 10000 wt. ppm, from 5 wt. ppm up to 8000 wt. ppm, from 55 wt. ppm up to 5500 wt. ppm or from 200 to 1000 wt. ppm Bromine from a bromine-containing species and/or source of bromine may be present in the reaction mixture in an amount ranging from 0.1 wt. ppm up to 20000 wt. ppm, from 200 wt. ppm up to 20000 wt. ppm, from 10 wt. ppm up to 10000 wt. ppm or from 1000 wt. ppm up to 2000 wt. ppm

Oxidation conditions or conditions maintained in the oxidation reactor may include a temperature from 120° C. to 250° C., for example from 170° C. to 190° C., and an oxygen partial pressure from 0.02 bar to 100 bar, from 0.02 bar to 21 bar, 0.2 bar to 100 bar or 0.2 bar to 21 bar. The total absolute pressure in the oxidation reactor may be from 1 bar to 200 bar, for example from 5 bar to 100 bar or from 10 bar to 20 bar. The molar yields of monomers in the oxidation step, for example, the molar yield of FDCA based FDCA-forming furan compounds in the oxidation feed or the molar yield of para-xylene based TPA in the oxidation feed, may be at least 60%, at least 70%, at least 80%, at least 90% or at least 95%. After the oxidation step, the resulting monomers, such as FDCA and/or TPA, can be separated from the oxidation reaction mixture, including the solvent, for further purification. At least a portion of the solvent from which these monomers are separated can then be recycled back to the dehydration reactor along with at least a portion of the unconverted FDCA-forming furan compounds. In particular embodiments, since FDCA and TPA are inherently insoluble in acetic acid or in a mixture of acetic acid and water under mild conditions, separation of FDCA and/or TPA in such embodiments can be easily accomplished by filtration and/or centrifugation after they have settled. from the oxidation reaction mixture. Specific oxidation methods are described, for example, in US 10538499.

Color stabilization of a composition based on a mixture of monomers or a separated fraction, optionally before or after derivatization (e.g. esterification)

In general, the oxidation step that is used to produce a monomer mixture composition consisting of two monomers can also, to some extent, produce color-forming by-products that contribute to the initial presence of color (preventing the desired, colorless appearance) and/or the formation of colored bodies over time, such as through aldol condensation reactions under acidic conditions, which lead to an increase in molecular weight. Particular color-forming by-products are the aldehyde derivatives of these monomers. For example, in the case of a composition based on a mixture of monomers or a co-product containing FDCA and TPA, this composition may additionally contain, in independent amounts, typically from 0.1 wt.% to 15 wt.%, typically from 0.3 wt. .% to 10 wt.% and from 1 wt.% to 3 wt.% (i) 5-formyl-2-furancarboxylic acid (FFCA), obtained by partial oxidation of FDCA and/or (ii) 4-carboxybenzaldehyde (4 -CBA), obtained as a result of the incomplete oxidation of TPA. These by-products, which are aldehyde derivatives of FDCA and TPA, respectively, are detrimental in terms of their tendency to color in both intermediates and final products. Similarly, in the case of isolated fractions enriched in certain monomers, such as FDCA (in the case of a fraction enriched in FDCA) or TPA (in the case of a fraction enriched in TPA), such fractions may contain aldehyde derivatives of the monomers with which they are enriched, such as FFCA and/ or 4-CBA, in independent amounts within the ranges above.

In addition, in some embodiments, the monomer mixture composition obtained from the oxidation step and/or the separated fractions of the monomer mixture composition enriched in either the first monomer or the second monomer may be subjected to a further derivatization step designed to prevent them. participation in reactions of aldol condensation, leading to the development of an undesirable color, for example, the step of providing esterification. However, in the case of an esterified composition based on a mixture of monomers (or an esterified co-product) containing 2,5-furandicarboxylic acid, dimethyl ether (FDME) as the main ester derivative of FDCA, and dimethyl terephthalate (DMT) as the main ester derivative of TPA , this composition may additionally contain, in independent amounts, typically from 0.1 wt.% to 15 wt.%, typically from 0.3 wt.% to 10 wt.% and often from 1 wt.% to 3 wt. .%, (i) 5-formyl-2-furancarboxylic acid methyl ester (FFME) obtained from the esterification of FFCA, and (ii) 4-carboxybenzaldehyde methyl ester (4-CME) obtained from the esterification of 4-CBA. These by-products, which are aldehyde ester derivatives of FDCA and TPA, respectively, as well as their non-esterified counterparts, are unfortunately also detrimental in terms of their tendency to color formation in both intermediates and final products. Similarly, in the case of isolated fractions enriched in certain monomer ester derivatives, such as FDME (in the case of a fraction enriched in FDME) or DMT (in the case of a fraction enriched in DMT), such fractions may also contain aldehyde-ester derivatives of the monomers with which they are enriched, such as FFME and 4-CME, in independent amounts within the ranges above.

In view of the above description, representative methods include the formation of products obtained at stages from the stage of providing dehydration to the stage of polymer formation, and these products may include one or more of: a composition based on a mixture of monomers; an esterified composition based on a mixture of monomers; the separated fraction enriched in this monomer; or an esterified separated fraction enriched in an ester derivative of such a monomer. Any of these products can be subjected to an additional color stabilization step, considering, for example, the presence even in an esterified composition based on a mixture of monomers or in esterified separated fractions enriched in monomers FFME and 4-CME, or the presence in a non-derivatized composition based on a mixture of monomers or separated monomer-enriched aldehyde fractions such as FFCA and 4-CBA, whereby the product is brought into contact with a color stabilizing medium, for example, to reduce the content of one or more color forming aldehydes and/or otherwise reduce the color of such a product or make it less susceptible to color formation .

According to one embodiment, the color stabilization step comprises bringing (i) a monomer mixture composition containing two monomers, or (ii) a separated fraction thereof, which can be enriched in this monomer (relative to the monomer mixture composition obtained in the oxidation step), (iii) an esterified monomer mixture composition containing two ester derivatives of the two monomers, or (iv) a separated fraction that can be enriched with this monomer ester derivative (relative to the esterified monomer mixture composition), in contact with hydrogen as a color stabilizing agent media for the selective hydrogenation of the color-forming aldehyde by-product, including any of the specific aldehyde by-products described above. The color-forming aldehyde by-products can be selectively hydrogenated under suitable hydrogenation conditions, converting their aldehyde groups to hydroxyalkyl groups to give the corresponding hydroxyalkyl derivatives of these by-products. In the case of a by-product which is an aldehyde derivative of FDCA or an ester derivative of FDCA, in which the aldehyde group is a formyl group, such a by-product can be selectively hydrogenated to its hydroxymethyl derivative. For example, in the case of FFCA (an aldehyde derivative of FDCA), this by-product can be selectively hydrogenated to its hydroxymethyl derivative, 5-hydroxymethyl-2-furoic acid (HMFCA). In the case of FFME (an aldehyde derivative of FDME, which is an ester derivative of FDCA), this by-product can be selectively hydrogenated to its hydroxymethyl derivative, 5-hydroxymethyl-2-furancarboxylic acid methyl ester (HMFME). In the case of 4-CBA (an aldehyde derivative of TPA), this by-product can be selectively hydrogenated to its hydroxymethyl derivative, 4-hydroxymethyl-benzoic acid (4-HMBA). In the case of 4-CME (an aldehyde derivative of DMT, which is an ester derivative of TPA), this by-product can be selectively hydrogenated to its hydroxymethyl derivative, methyl-(4-hydroxymethyl)benzoate (4-HMMB).

In the color stabilization steps comprising contacting a given monomer mixture, separated fraction or otherwise esterified monomer mixture or separated fraction composition as described herein with hydrogen, the contacting may be carried out in the presence of a hydrogenation catalyst. , usually in solid form and containing at least one noble metal, to obtain a corresponding stabilized composition (stabilized composition based on a mixture of monomers) or separated fraction, or otherwise, a stabilized esterified composition (stabilized esterified composition based on a mixture of monomers) or separated fraction . Particular hydrogenation catalysts that can selectively hydrogenate the aldehyde by-products described herein, advantageously without significant hydrogenation of the furan rings or benzene rings of the corresponding monomers or ester derivatives of the monomers, involve the noble metals Pt and Ru along with the promoter metal Sn. Other possible methods for the recovery of aldehyde by-products are described in international application PCT/US2018/041694 (published as WO 2019/014382).

In one embodiment, the color stabilization step comprises bringing (i) a monomer mixture composition containing two monomers, or (ii) a separated fraction that can be enriched in that monomer (relative to the monomer mixture composition), (iii) an esterified composition to based on a mixture of monomers containing two ester derivatives of the two monomers, or (iv) a separated fraction that can be enriched in this ester derivative of the monomer (relative to the esterified composition based on a mixture of monomers), in contact with a color stabilizing additive compound as a stabilizing environment color. Color stabilizing additives can advantageously reduce the amount of color formation during the periods (eg, long storage periods) between the synthesis of the monomer(s) and its/their use in the preparation of the biobased polymer(s) as described herein. Therefore, “contacting” with a color stabilizing additive compound can result in a monomer mixture, separated fraction or otherwise esterified monomer mixture or separated fraction composition as described herein containing one or more additives. color stabilizing compounds. Representative compositions may include, consist of, or essentially consist of a monomer(s) (for example, FDCA and TPA in combination or in separated fractions enriched in one or the other) or their ester derivative(s) (for example , FDME and DMT in combination or in separated fractions enriched in one or the other) and one or more additional color stabilizing compounds.

Since FDCA and TPA, as well as FDME, DMT and other ester derivatives are solid at room temperature, the color stabilization step may include, for example, melting the monomer(s) or ester derivative(s) of interest, dispersing the necessary additive (s) connection(s), evenly distributed(s) in the melt, and optionally curing the resulting stabilized composition (for example, through active cooling or simply allowing the composition to return to ambient conditions). Conveniently, however, the desired color stabilizing compound(s) can be added directly to (a) the oxidation feed for synthesizing a monomer mixture composition, (b) any stream of that monomer mixture composition, a separated fraction or otherwise esterified composition based on a mixture of monomers or a separated fraction as described herein that is used in the polymer formation step, and/or (c) introduced into the reaction mixture of the polymer formation step at any sub-step, such as (i) providing esterification or transesterification; and (ii) polymerization by polycondensation.

Representative color stabilizing additives include substituted phenolic compounds, which refer to compounds having at least one phenolic moiety, but possibly two or more phenolic moieties, in which the benzene ring(s) of such moiety or moieties has at least one substituent other than a hydroxyl substituent. Specific examples of such substituents are alkoxy and alkyl substituents, with methoxy and t-butyl substituents being preferred. Therefore, examples of substituted phenolic compounds include alkoxy-substituted (e.g., methoxy-substituted) and alkyl-substituted (e.g., t-butyl-substituted) phenolic compounds, which are compounds having at least one phenol moiety, but possibly , two or more phenolic moieties, with one or more alkoxy (eg, methoxy) and alkyl (eg, t-butyl) substituents, respectively. In the case of tert-butyl-substituted phenol compounds, these compounds are often referred to as "heavy phenol compounds" in view of the steric hindrance resulting from the geometry of these substituents.

Substituted phenolic compounds include butylated hydroxyanisole (BHA); 2,6-dimethoxyphenol (DMP); 2,6-di-tert-butyl-4-methoxylphenol (DTMP); pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate (PETC); 2-tert-butylhydroquinone (TBHQ); ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate); and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate. Of these compounds, (i) BHA, DMP, and DTMP are methoxy-substituted phenolic compounds, and (ii) DTMP, PETC, TBHQ, ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m -tolyl)-propionate) and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate are tert-butyl-substituted compounds of the phenol series. Other color stabilizing additive compounds include phenyl-substituted amines (eg 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (XDPA)), phosphites (eg tris(2,4-di-tert-butylphenyl)phosphite) and vitamins -antioxidants (for example, ascorbic acid). The PETC compound is commercially available as ^Irganox® 1010 (BASF) or ^Dovernox® 10 (Dover Chemical Corp.); the compound ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate) is commercially available as ^Irganox® 245 (BASF); the compound tris(2,4-di-tert-butylphenyl)phosphite is commercially available as ^Irgafos® 168 (BASF); and the compound octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate is commercially available as ^Irganox® 1076 (BASF) or ^Dovernox® 76 (Dover Chemical Corp.).

The color stabilization step may include the use of a combination of color stabilizing additive compounds as the color stabilizing medium, including a combination of any of the compounds and/or classes of compounds described above, for example a combination of one or more tert-butyl substituted phenyl series compounds and one or more phosphites. For example, a combination of 50 wt% PETC and 50 wt% tris(2,4-di-tert-butylphenyl)phosphite is commercially available under the name ^Irganox® B255 (BASF). A combination of 20 wt.% octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 80 wt.% tris(2,4-di-tert-butylphenyl)phosphite is commercially available under the name ^Irganox® B900 (BASF). A combination of 50 wt% PETC and 50 wt% tris(2,4-di-tert-butylphenyl)phosphite is commercially available under the name ^Irganox® B225 (BASF).

One or more additional color stabilizing compounds may be present in products such as (i) a monomer mixture composition containing two monomers, or (ii) a fraction separated from it, which can be enriched in this monomer (in relation to the composition by based on a mixture of monomers), (iii) an esterified composition based on a mixture of monomers containing two ester derivatives of the two monomers, (iv) a fraction separated from it, which can be enriched in this ester derivative of the monomer (in relation to the esterified composition based on a mixture of monomers), or (v) a biobased polymer as described herein. Such a biobased polymer may have both furandicarboxylate moieties and terephthalate moieties, or may have all or substantially all of the furandicarboxylate moieties, or all or substantially all of the terephthalate moieties. In any such product, the amount or total amount in the case of a combination may be, as a rule, from 10 wt. ppm up to 1 wt. ppm, usually from 50 wt. ppm up to 2000 wt. ppm, and often from 50 wt. ppm up to 1500 wt. ppm According to preferred embodiments, an additional amount of BHA may be present in any such product (eg, containing both FDCA and TPA to stabilize these monomers) in an amount of 100 wt. ppm up to 500 wt. ppm, or an additional amount of Irganox ^® 245 may be present in any such product (eg containing both FDCA and TPA to stabilize these monomers) in an amount of 800 wt. ppm up to 1200 wt. ppm. These and other color stabilizing additives, as well as other aspects related to their use in color stabilization of process streams to produce bio-based polymers, are described in WO 2019/246034).

In the methods described herein, the color stabilization and esterification steps are optional and may be performed in any order, depending on the intended purpose of the treatment. Accordingly, for the purposes of the present invention and with reference to the drawings, it is to be understood that any "stabilized esterified" composition (stabilized esterified composition based on a mixture of monomers) containing two monomer ester derivatives (for example, both FDME and DMT), or any The "stabilized esterified" fraction enriched in a given ester derived monomer (e.g., FDME or DMT) as described herein may be equivalent to (i) if the color stabilization step is omitted, an "esterified" composition based on a mixture of monomers containing two ester monomer derivatives (for example, both FDME and DMT), or an "esterified" fraction enriched in that monomer ester derivative (for example, FDME or DMT), or (ii) if the step of providing esterification of a "stabilized" mixture-based composition is omitted a monomer containing two monomers (eg, both FDCA and TPA), or a "stabilized" fraction enriched in that monomer (eg, FDCA or TPA). For the purposes of the present invention and with reference to the drawings, it should also be understood that the preparation of a "stabilized esterified" composition (stabilized esterified composition based on a mixture of monomers) containing two monomer ester derivatives (for example, both FDME and DMT), or "stabilized "esterified" fraction enriched in a given ester derivative monomer (e.g., FDME or DMT) can be achieved by first color stabilization and then providing esterification, by first providing esterification and then color stabilization, or by performing both steps simultaneously (e.g., by bringing the reaction mixture to esterification in contact with a color stabilizing medium as described herein).

The steps for allowing monomers such as FDCA and TPA to be esterified to give ester derivatives involve reacting these monomers with an esterifying agent such as an alcohol, such as methanol if dimethyl ether is desired, or ethanol if diethyl ether is desired, or possibly phenol. if diphenyl ether is required. The reaction of FDCA and/or TPA or other monomer(s) with an appropriate alcohol or phenol can be carried out in an esterification reaction mixture containing a high boiling point solvent (e.g. dimethyl sulfoxide, dimethylacetamide, sulfolane, FDME, γ-butyrolactone, isosorbide or its dimethyl ether, propylene carbonate, adipic acid, isophorone, ethyl phenyl ether, diphenyl ether, dibenzyl ether, aromatic 200 liquid, butylphenyl ether, methylheptyl ketone, ethyl phenyl ketone, 2'-hydroxyacetophenone, decahydronaphthalene, tetrahydronaphthalene, etc.) under suitable esterification conditions. These may include temperatures from 30°C (86°F) to 350°C (662°F) and atmospheric pressure to 3.5 megapascals (MPa), and the esterification reaction may be carried out together with distillation (according to the reactive distillation method ) to separate FDME, DMT or other ester derivative.

In preferred embodiments, the step of providing esterification of (i) a monomer mixture composition (or stabilized monomer mixture composition) consisting of two monomers, or (ii) a separated fraction (or stabilized separated fraction) that can be enriched in a given monomer ( relative to a composition based on a mixture of monomers), involves the reaction of any such composition based on a mixture of monomers or a separated fraction with methanol as an esterification agent. For example, in the case of a monomer mixture composition (or a stabilized monomer mixture composition) obtained from an oxidation step containing both FDCA and TPA, ensuring that the monomer mixture composition (or stabilized monomer mixture composition) is esterified can include reacting with methanol to form an esterified monomer mixture composition (or a stabilized monomer mixture esterified composition) containing FDME and DMT. In particular embodiments, esterification of the monomer mixture or stabilized composition is required because monomer ester derivatives such as FDME and DMT have lower boiling points than their dicarboxylic acid parent compounds and are more easily separated by distillation, considering this and their relative volatility. In the case of any(s) stage(s) providing esterification, as described herein in general and/or with respect to the embodiments illustrated in the figures, it is possible that further(s) subsequent(s) stage(s) can be applied to converting the ester derivative(s) (e.g. FDME and/or DMT) obtained from the esterification step back to the parent form of the carboxylic acid(s) (e.g. FDCA and/or TPA) , for example, to the stage(s) of the formation of the polymer, as described in this document.

In view of the processing options described herein with respect to the color stabilization, esterification and/or separation steps, it can be appreciated that representative compositions based on a mixture of monomers after oxidation may contain, as color-forming by-products, an aldehyde derivative of FDCA (for example, FFCA) and an aldehyde derivative of TPA (e.g., 4-CBA), and the methods may include selective hydrogenation of one or both of the FDCA aldehyde derivative and the TPA aldehyde derivative (e.g., reducing their concentration in a given process stream to improve the color and/or color stability of the copolymer obtained from this process flow). This step of selectively hydrogenating one or both of the FDCA aldehyde derivative and the TPA aldehyde derivative can be performed after separation of the monomer mixture composition into an FDCA-rich fraction and a TPA-rich fraction. In other embodiments wherein the monomer mixture composition comprises an aldehyde derivative of FDCA and an aldehyde derivative of TPA, the methods may further comprise the step of causing one or both of FDCA and TPA to be esterified to produce, as additional color forming by-products, one or both of the aldehyde derivative of ester. an FDCA derivative (eg FFME); and an aldehyde derivative of a TPA ester derivative (eg 4-CME). Representative methods in this case may further include selectively hydrogenating one or both of the FDCA ester aldehyde derivative and the TPA ester aldehyde derivative (e.g., reducing their concentration in a given process stream to improve the color and/or color stability of the copolymer ultimately obtained from this process flow). In the case of esterification of both FDCA and TPA, this may include allowing these materials to be esterified simultaneously in a monomer mixture composition by reaction with an esterifying agent in the presence or absence of a suitable esterification catalyst to produce an esterified monomer mixture composition containing both the aldehyde derivative an ester derivative of FDCA and an aldehyde derivative of an ester derivative of TPA. Esterification of both FDCA and TPA (for example, by combining the monomer mixture composition with an esterifier (alcohol) in the presence or absence of an esterification catalyst and under appropriate process conditions to effect esterification of FDCA and TPA in the monomer mixture composition) can be performed before separating the esterified monomer mixture composition into a first fraction enriched in the FDCA ester derivative and a second fraction enriched in the TPA ester derivative. Alternatively, in the case of esterification of one or both of FDCA and TPA, this may include esterification of one or both of the FDCA-enriched fraction and the TPA-enriched fraction by reaction with an esterifying agent after separating the monomer mixture composition into an FDCA-enriched fraction, and a fraction enriched in TPA.

Obtaining a polymer from a composition based on a mixture of monomers/oxidation product or from separated fractions enriched in monomers

Any of the monomer mixture oxidation products (e.g. containing both FDCA and TPA) or individual fractions thereof (e.g. rich in FDCA or enriched in TPA, relative to the oxidation products of the monomer mixture from which these fractions are derived) or monomer mixture esterified compositions ( containing both FDME and DMT) or their separated fractions (e.g. enriched in FDME or enriched in DMT, relative to the oxidation products of the mixture of esterified monomers from which these fractions are derived), optionally subjected to a color stabilization step, can be used to make polymers. As a result of obtaining a polymer directly from the combined oxidation product of monomers, a copolymer can be obtained having both FDCA-related fragments (for example, furandicarboxylate fragments) and TPA-related fragments (for example, terephthalate fragments), while as a result of obtaining a polymer from a separated fraction, a copolymer can be obtained , having FDCA-related moieties and substantially no (or at least having fewer) TPA-related moieties (e.g., providing an essentially bio-based copolymer, with p-xylene typically derived from petroleum), or, in other words, a copolymer having TPA-related moieties and essentially no (or at least containing less) FDCA-related moieties (which may be necessary for some practitioners given the well-developed infrastructure for PET processing and given the difficulty of users switching to a new polymer ). In general, representative polymer preparation steps may include, to obtain polyesters, (A)(i) providing an esterification of a composition based on a mixture of monomers or a separated fraction thereof, as described herein, or (A)(ii) providing an esterification of an esterified composition based on mixtures of monomers or a separated fraction thereof, as described herein, and (B) polymerization by polycondensation.

Representative steps for preparing the polyester polymer include polymerizing the monomers and ester derivatives of the monomers described herein, in particular FDCA and/or TPA monomers and ester derivatives of FDME and/or DMT monomers, with suitable comonomers such as diols. For example, ethylene glycol can be used as a comonomer to produce PEF (from FDCA or FDME) or PET (from TPA or DMT). 1,3-Propanediol as a comonomer can be used to form a polymer of trimethylene and furan and dicarboxylate (PTF) (from FDCA or FDME) or polypropylene terephthalate (from TPA or DMT).

Particular methods may include preparing a precursor composition comprising a prepolymer that is an esterified intermediate such as the reaction product of FDCA and/or TPA with comonomer, or a transesterified intermediate such as the reaction product of FDME and/or DMT with comonomer. The prepolymer, whether an esterified intermediate or a transesterified intermediate, is functionalized with alcohol terminals (for example, not TPA carboxylate terminals or FDME or DMT methyl terminals) and can therefore be polycondensed to form a copolymer as described herein, in in particular a copolymer of alkylene and furan and a dicarboxylate, a copolymer of alkylene and terephthalate, or a copolymer containing both alkylene, furan and dicarboxylate moieties and alkylene and terephthalate (or alkylene and terephthalate) moieties. Similarly, the aldehyde derivatives described herein present in monomeric compositions (e.g., FFCA in FDCA monomeric composition, 4-CBA in TPA monomeric composition, FFME in FDME monomeric composition, or 4-CME in DMT monomeric composition) that are used to obtain the precursor compositions will become esterified or transesterified under the conditions used to prepare the precursor composition. However, since the aldehyde group is retained in such by-products in the precursor composition, by subjecting the composition to the color stabilization step described herein, i.e. by contacting with hydrogen or a color stabilizing additive compound, either of which can serve as a color stabilizing medium, the color stabilizing benefits described herein can be achieved.

Therefore, methods for producing a polyester polymer (eg, a copolyester) may include both a first stage of providing esterification or transesterification to obtain an intermediate product (prepolymer), and then a second stage of polycondensation. The first step can be catalyzed by an esterification/transesterification catalyst between 150°C (302°F) and 250°C (482°F) and is carried out until the concentration of starting monomer(s) or ester(s) ) derivative(s) of the monomer(s) will not decrease to less than 3 mol. %. The catalyst may include an organotin (IV) compound present in a concentration of 0.01 mol. % to 0.2 mol. % in the reaction mixture forming the polymer, relative to the original(s) monomer(s) or ester(s) derivative(s). Therefore, the prepolymer as described herein may be the reaction product of two diol monomers and one monomer bearing either a furandicarboxylate moiety or a terephthalate (benzenecarboxylate) moiety that is ultimately present in the backbone of the resulting polymer.

Other diols of interest for the preparation of the intermediate (prepolymer) include diols such as FDCA, which can be obtained biologically, such as in the case of isohexides. These compounds are bicyclic rigid diols that differ only in the orientation of the hydroxyl groups at the C ₂ and C ₅ positions of the ring and can be obtained by cyclodehydration of hexitols. For example, isomannide can be obtained (endo-endo) from mannitol, isosorbide (exo-endo) can be obtained from sorbitol, and isoidide (exo-exo) can be obtained from iditol. Regardless of the specific diol, the resulting intermediate product (prepolymer) can optionally be isolated from the reaction mixture of the first stage of the reaction, although this is usually not necessary. The second polycondensation step can be catalyzed and carried out under reduced pressure (for example, 100 pascals (Pa) or less), at a temperature in the range from the melting point of the resulting copolymer to 30° C. (54° F) above this temperature, and preferably at a temperature of at least measure 180° C (356° F). The polycondensation catalyst may include a tin (II) compound, for example, tin (II) oxide or an organotin (II) compound. Alternatively, a titanium-based catalyst may be used, such as titanium or a titanium chelate having various ligands, which may include alkoxides, such as propoxide or tert-butoxide. Therefore, titanium(IV) propoxide and titanium(IV) tert-butoxide are representative catalysts.

As described above, FDCA and/or TPA present together or in separate fractions enriched in a given monomer can be used to form polymers other than polyester polymers. For example, polyamide polymers can be prepared by reacting one or both of FDCA and TPA, alone or in combination, with a comonomer having at least two amino groups (e.g., a diamine) to produce a polyamide having one or both of the FDCA-related moieties. and related TPA fragments. Suitable comonomers include aliphatic diamines such as hexamethylenediamine and aromatic diamines such as paraphenylenediamine. As also described above, an FDCA derivative and/or a TPA derivative present together or in separate fractions enriched in a given monomer can be used to form polyester polymers. For example, polyester polymers can be prepared by reacting, as a comonomer, a hydroxyl (alcohol) derivative of one or both of FDCA and TPA (e.g., a diol derivative of one or both of FDCA and TPA), alone or in combination, with a polyacid ( eg FDCA or TPA) or an ester derivative thereof to form a polyester having one or both of the FDCA-related moieties and the TPA-related moieties. Suitable comonomers that are hydroxyl derivatives of FDCA include furan-2,5-diol and furan-2,5-dimethanol, and suitable comonomers that are hydroxyl derivatives of TPA include hydroquinone and benzene-1,4-dimethanol.

As further described above, an FDCA derivative and/or a TPA derivative present together or in separate fractions enriched in a given monomer can be used to form polymers other than polyester polymers. For example, polyurethane polymers can be prepared by reacting, as a comonomer, a hydroxyl (alcohol) derivative of one or both of FDCA and TPA (e.g., a diol derivative of one or both of FDCA and TPA), alone or in combination, with a polyisocyanate to form a polyurethane having one or both of the FDCA-related moieties and the TPA-related moieties. Suitable comonomers that are hydroxyl derivatives of FDCA include those described above in relation to the preparation of polyester polymers. Suitable polyisocyanates include diisocyanates, in particular aromatic diisocyanates such as toluene diisocyanate, methylene diphenyl diisocyanate and polymeric methylene diisocyanates. In other embodiments, polyamide polymers can be prepared by reacting, as a comonomer, an amine derivative of one or both of FDCA and TPA (e.g., a diamino derivative of one or both of FDCA and TPA), alone or in combination, with a polyacid (e.g., FDCA or TPA) to produce a polyamide having one or both of the FDCA-related moieties and the TPA-related moieties. Suitable FDCA amino comonomers include furan-2,5-diamine and furan-2,5-dialkylamines such as furan-2,5-dimethanamine and suitable TPA amine comonomers include benzene-1,4-diamine and benzene-1,4-dialkylamines such as benzene-1,4-dimethanamine. In other embodiments, polyamide polymers can be prepared by reacting an acyl derivative of one or both of FDCA and TPA (e.g., a diacyl chloride derivative of one or both of FDCA and TPA), alone or in combination, with a comonomer having at least two amino groups ( for example, a diamine) to form a polyamide having one or both of the FDCA-related moieties and the TPA-related moieties. Suitable acyl derivatives of FDCA include furan-2,5-diformyl chloride and furan-2,5-dialkyl chlorides such as furan-2,5-diacetyl chloride, and suitable acyl derivatives of TPA include benzene-1,4-diformyl chloride and benzene-1, 4 dialkyl chlorides such as benzene-1,4-diacetyl chloride. Suitable comonomers include aliphatic diamines such as hexamethylenediamine and aromatic diamines such as paraphenylenediamine. In other embodiments, polyurethane polymers can be prepared by reacting an isocyanate derivative of one or both of FDCA and TPA (e.g., a diisocyanate derivative of one or both of FDCA and TPA), alone or in combination, with a comonomer having at least two hydroxyl groups. (eg, a diol) to form a polyurethane having one or both of the FDCA-related moieties and the TPA-related moieties. Suitable isocyanate derivatives of FDCA include furan-2,5-diisocyanate and furan-2,5-dialkylisocyanates such as furan-2,5-dimethaneisocyanate and suitable isocyanate derivatives of TPA include benzene-1,4-diisocyanate and benzene-1,4 -dialkyl isocyanates, such as benzene-1,4-dimethaneisocyanate. Suitable comonomers include diols, such as those described above for the preparation of the intermediate (prepolymer) used for the final preparation of the polyester polymer. In yet other embodiments, polycarbonate polymers can be made by reacting a hydroxyl (alcohol) derivative of one or both of FDCA and TPA (e.g., a diol derivative of one or both of FDCA and TPA), alone or in combination, with phosgene to form a polycarbonate, having one or both of FDCA-related fragments and TPA-related fragments. Suitable hydroxyl derivatives of FDCA include those described above with respect to comonomers for the formation of polyester polymers.

Exemplary embodiments of obtaining a composition based on a mixture of monomers containing FDCA and TPA

The method shown in FIG. 1 includes the steps for preparing a composition based on a mixture of monomers containing FDCA and TPA, as described above, including the steps of providing dehydration 100, oxidation 200, optional color stabilization 50, optional esterification 55, and polymer formation 300. According to this figure, a dehydration feedstock 10 containing one or more carbohydrates having a six-carbon sugar unit is dehydrated 100 to produce a dehydration product 12, all or part of which can be used as a component of the oxidation feedstock. In some embodiments, a contaminating portion of the dehydration product 12, such as the portion 11 that is concentrated in humins (eg, in a filtration retentate), may be removed to provide a purified portion 12' of the dehydration product 12 that can be used as a component or possibly of all raw materials for oxidation. The depicted method may include bringing the dehydration product 12 or its purified part 12' in the presence of oxygen, for example introduced in the oxygen-containing feed 16 (eg air), into contact with an oxidation catalyst. According to one embodiment, the second component of the oxidation feedstock, in addition to the dehydration product 12 or its purified part 12', is a para-xylene-containing feedstock 14. the purified part 12', and (ii) the TPA obtained from the oxidation of para-xylene is withdrawn from the oxidation stage 200 (eg, the oxidation reactor). All or part of the composition based on a mixture of monomers (or oxidation product) 18 can be used in stage 300 of polymer formation, optionally after color stabilization 50 to obtain a stabilized composition 20 and/or esterification 55, for example, to obtain a stabilized esterified composition 22 (if both stages). As described herein, these optional steps may be performed in any order. The monomer mixture composition 18 can be obtained in the oxidation step 200, for example in the oxidation reactor stream from which the solvent recycle 15 is separated (for example, based on the relative insolubility of the monomers in the monomer mixture composition 18 in a solvent or solvent system for furan compounds). FDCA-forming series in the dehydration product 12). All or part of the solvent recycle 15 may be fed back or recycled to the dehydration stage 100 (e.g., to the dehydration reactor), and a fresh make-up 17 of the solvent may be added to the solvent recycle 15 or otherwise directly to the dehydration stage 100.

According to another embodiment, all or part of the para-xylene added in the subsequent oxidation step 200 may be present in the dehydration product 12 or its purified portion 12'. If a portion of the para-xylene is present, the para-xylene-containing feedstock 14 may be a second charge that is added directly to the oxidation stage 200 (e.g., an oxidation reactor), while the fresh solvent make-up 17 may be a fresh make-up of steam -xylene, which is added to the solvent recycle 15 or otherwise directly to the dehydration stage 100 (eg, to the dehydration reactor). Accordingly, the para-xylene present in dehydration product 12 may be the combined amount of fresh make-up 17 and the amount present in solvent recycle 15 (eg, during stationary operation). By adding at least a portion of the para-xylene required in the process to the dehydrogenation step for use as a solvent, a number of advantages can be obtained in terms of various operating efficiencies as described above.

Representative methods may include (A) stabilizing 50 the color of the monomer mixture (or oxidation product) composition 18 by adding (or bringing into contact with) a color stabilizing medium 19 to obtain a stabilized composition 20 containing FDCA and TPA; and (B) optionally after (A) providing an esterification 55 of the stabilized composition 20 by reaction with an esterifier 21 to obtain a stabilized esterified composition 22 containing ester derivatives of FDCA and TPA (eg, diesters of FDME and DMT). Following (A), the method for the purpose of producing a copolyester from FDCA and TPA may further comprise reacting the stabilized composition 20 containing FDCA and TPA with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a stabilized coesterified intermediate. (prepolymer) composition comprising (i) a first esterified intermediate which is the reaction product of FDCA and comonomer, and (ii) a second esterified intermediate which is the reaction product of TPA and comonomer, and polymerization of the stabilized coesterified intermediate composition by polycondensation of the first and second esterified intermediates to give copolymer product 26 comprising a copolymer having furandicarboxylate moieties and terephthalate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 300 . After (B), the method may further comprise reacting the stabilized esterified composition 22 containing the FDCA and TPA ester derivatives with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a stabilized co-esterified intermediate (prepolymer) composition containing (i) a first interesterified intermediate, which is the reaction product of the FDCA ester derivative and comonomer 24, and (ii) a second interesterified intermediate, which is the reaction product of the TPA ester derivative and comonomer 24, and polymerization of the stabilized co-esterified intermediate composition by polycondensation of the first and second interesterified intermediates products to obtain a copolymer product 26, providing a copolymer having furandicarboxylate fragments and terephthalate fragments. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 300 .

In the case where esterification and color stabilization are performed in reverse order, then the method may include (A) providing esterification of the monomer mixture composition 18 by reacting with the esterification agent 21 to obtain an esterified monomer mixture composition containing ester derivatives of FDCA and TPA , and (B) optionally after (A) stabilizing the color of the esterified monomer mixture composition (or ester mixture composition) by adding color stabilizing medium 19 to obtain a stabilized composition 22 containing stabilized ester derivatives of FDCA and TPA. After (A), the method for the purposes of producing a copolyester may further comprise reacting an esterified mixture of monomer composition containing both FDCA and TPA ester derivatives with comonomer 24 having at least two hydroxyl groups (e.g., a diol), with obtaining a co-transesterified intermediate (prepolymer) composition containing (i) a first transesterified intermediate product, which is the reaction product of an ester derivative of FDCA and a comonomer, and (ii) a second transesterified intermediate, which is a product of the reaction of an ester derivative of TPA and a comonomer, and polymerization of the co-transesterified intermediate composition by means of polycondensation of the first and second esterified intermediates to form a copolymer product 26 comprising a copolymer having furandicarboxylate moieties and terephthalate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 300 . After (B), the method may further comprise reacting the stabilized esterified composition 22 containing both FDCA and TPA ester derivatives with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a stabilized co-esterified intermediate (prepolymer) a composition comprising (i) a first interesterified intermediate, which is the reaction product of an FDCA ester derivative and a comonomer, and (ii) a second interesterified intermediate, which is a reaction product of a TPA ester derivative and a comonomer, and polymerizing the stabilized co-esterified intermediate composition by polycondensation of the first and second interesterified intermediate products to obtain a copolymer product 26, providing a copolymer having furandicarboxylate fragments and terephthalate fragments. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 300 .

The method shown in FIG. 2 includes the steps shown in FIG. 1 to produce a monomer blend or companion product composition containing FDCA and TPA, including the steps of dehydration 100, oxidation 200, optional color stabilization 50, and optional esterification 55. In this figure, all or part of the monomer blend formulation 18 , optionally stabilized composition 20, or optionally stabilized esterified composition 22 is used in separation step 60, for example, to obtain fractions that can be enriched in one monomer or relative to another monomer or ester derivatives of one monomer relative to ester derivatives of another monomer. As used herein, "rich" refers to a higher concentration of a given monomer or ester derivatives of that monomer compared to the product prior to separation. The fraction enriched in a given monomer or ester derivatives of that monomer (e.g., FDCA, TPA, mono- and di-ester derivatives of FDCA, and mono- and di-ester derivatives of TPA) may contain at least 50% by weight, at least 75 wt.% or at least 90 wt.% of this monomer or ester derivatives of this monomer. Therefore, a fraction enriched in a given monomer or in ester derivatives of a given monomer may also be "lean" (have a lower concentration) in a given monomer or in ester derivatives of a given monomer which is also present in the product prior to separation. For example, the FDCA-enriched fraction may be depleted in TPA such that the fraction may be substantially free of TPA (eg, may contain less than 5 wt%, less than 3 wt%, or less than 1 wt%) of the compound. The TPA-rich fraction may be depleted in FDCA such that the fraction may be substantially free of FDCA (eg, may contain less than 5 wt%, less than 3 wt%, or less than 1 wt%) of this compound. The FDCA ester-enriched fraction (or FDCA-enriched esterified fraction) may be depleted in TPA esters such that the fraction may be substantially free of these mono- and di-ester derivatives (e.g., may contain less than 5 wt.%, less 3% by weight or less than 1% by weight of TPA ester derivatives. The TPA ester-enriched fraction (or the TPA-rich esterified fraction) may be depleted in FDCA ester derivatives such that the fraction may be substantially free of these ester derivatives (e.g., may contain less than 5 wt.%, less than 3 wt.%, or less than 1 wt.%) mono - and di-ester derivatives of FDCA.

Separation step 60, according to the embodiment of FIG. 2 may be made according to any of a number of techniques such as fractional solidification (based on melting point difference); crystallization, optionally after extraction in an aqueous or organic medium (based on solubility difference); adsorbent or chromatographic methods, including simulated moving bed (SMB) chromatography (based on molecular size/structure difference); and distillation, optionally with off-gas or extractive solvent (based on relative volatility difference). In one embodiment, the resulting esterification step 55 produces resultant ester monomers more suitable for separation by distillation. Accordingly, separation 60 may include distillation of the esterified monomer mixture composition (or esterified oxidation product) 22 (optionally after color stabilization step 50) into a first fraction 251 enriched in FDCA esters (e.g., FDME) and a second fraction 252 enriched in esters. TPA derivatives (eg DMT). In particular embodiments, separation step 60 can be used to separate monomer mixture composition 18 (optionally after color stabilization 50) into a first fraction 251 enriched in FDCA and a second fraction 252 enriched in TPA. After the separation step 60, the optional color stabilization steps 501/502, the optional esterification steps 551/552 and the polymer formation steps 301/302 can be performed on the separated fractions, in the manner described above.

According to the possible embodiments shown in FIG. 2, the methods may further comprise (A) color stabilizing the first FDCA-enriched fraction 251 by adding color stabilizing medium 19 to obtain an FDCA-enriched stabilized fraction 201, and (B) optionally after (A) providing esterification of the FDCA-enriched stabilized fraction 201 , by reacting with the esterification agent 21 to obtain a stabilized FDCA-enriched esterified fraction 221 containing an ester derivative of FDCA. After (A), the method may further comprise reacting the stabilized FDCA-enriched fraction 201 with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to obtain a stabilized esterified intermediate (prepolymer) composition comprising (i) the first esterified an intermediate that is the reaction product of FDCA and comonomer and is substantially free of (ii) a second esterified intermediate that is the reaction product of TPA and comonomer, and polymerization of the stabilized esterified intermediate composition by polycondensation of the first esterified intermediate to give polymer product 261, comprising a polyester having furandicarboxylate moieties and substantially free of terephthalate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 301 . After (B), the method may further comprise reacting the FDCA-enriched stabilized esterified fraction 221 containing an FDCA ester derivative (particularly a diester) with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to obtain a stabilized interesterified an intermediate (prepolymer) composition containing (i) a first transesterified intermediate, which is the reaction product of a mono- and/or di-ester derivative of FDCA and a comonomer, and essentially does not contain (ii) a second transesterified intermediate, which is the reaction product of an ester derivative of TPA and a comonomer, and polymerizing the stabilized interesterified intermediate composition by polycondensing the first interesterified intermediate to form a polyester product 261 comprising a polyester having furandicarboxylate moieties and substantially free of terephthalate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 301 .

According to other possible embodiments shown in FIG. 2, the methods may further comprise (A) causing the first FDCA-enriched fraction 251 to be esterified by reacting with the esterification means 21 to obtain an esterified FDCA-enriched fraction containing the FDCA ester derivative, and (B) optionally after (A) stabilizing the color of the esterified FDCA enriched fraction by adding color stabilizing medium 19 to obtain a stabilized esterified FDCA enriched fraction 221. Following (A), the methods may further comprise reacting the esterified FDCA-enriched fraction containing the FDCA ester derivative with comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a transesterified intermediate (prepolymer) composition comprising (i ) a first interesterified intermediate, which is the reaction product of a mono- and/or di-ester derivative of FDCA and a comonomer, and substantially free of (ii) a second interesterified intermediate, which is the reaction product of a TPA ester derivative and a comonomer, and polymerizing the interesterified intermediate composition by means of polycondensation of the first transesterified intermediate to give copolymer product 261, comprising a copolymer having furandicarboxylate moieties and substantially free of terephthalate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 300 . Following (B), the methods may further comprise reacting the stabilized esterified fraction 221 with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a stabilized transesterified intermediate (prepolymer) composition comprising (i) a first transesterified intermediate, which is the reaction product of a mono- or di-ester derivative of FDCA and a comonomer, and is substantially free of (ii) a second transesterified intermediate product, which is a reaction product of a TPA ester derivative and a comonomer, and the polymerization of the stabilized interesterified intermediate composition by polycondensation of the first interesterified intermediate product to obtain a copolymer product comprising a copolymer having furandicarboxylate moieties and substantially free of terephthalate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 301 .

According to other possible embodiments shown in FIG. 2, the methods may further comprise (A) color stabilizing the second TPA-rich fraction 252 by adding color stabilizing medium 19 to obtain a stabilized TPA-rich fraction 202; and (B) optionally after (A) providing esterification of the stabilized TPA-rich fraction 202 by reaction with the esterifier 21 to obtain a stabilized esterified TPA-rich fraction 222 containing a TPA ester derivative. After (A), the methods may further comprise reacting the stabilized TPA-enriched fraction 202 with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a stabilized esterified intermediate (prepolymer) composition comprising (i) the first esterified an intermediate that is the reaction product of TPA and comonomer and is substantially free of (ii) a second esterified intermediate that is the reaction product of FDCA and comonomer, and polymerizing the stabilized esterified intermediate composition by polycondensing the first esterified intermediate to form a 262 polyester product comprising a polyester having terephthalate moieties and essentially free of furandicarboxylate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 302. After (B), the methods may further comprise reacting the stabilized TPA-enriched esterified fraction 222 containing a TPA ester derivative (particularly a diester) with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a stabilized, a transesterified intermediate (prepolymer) composition comprising (i) a first transesterified intermediate which is the reaction product of a mono- and/or di-ester derivative of TPA and a comonomer. and essentially free of (ii) a second interesterified intermediate product, which is the reaction product of an ester derivative of FDCA and a comonomer, and polymerization of the stabilized interesterified intermediate composition by polycondensation of the first interesterified intermediate product to obtain a polyester product 262, providing a polyester having terephthalate fragments and essentially not containing furandicarboxylate fragments. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 302.

According to other possible embodiments shown in FIG. 2, the methods may further comprise (A) causing the second TPA-rich fraction 252 to be esterified by reacting with the esterification agent 21 to produce an esterified TPA-rich fraction containing a TPA ester derivative, and (B) optionally after (A) stabilizing the color of the esterified fraction enriched in TPA by adding color stabilizing medium 19 to obtain a stabilized esterified fraction 222 enriched in TPA. Following (A), the methods may further comprise reacting the TPA-rich esterified fraction containing the TPA ester derivative with comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a transesterified intermediate (prepolymer) composition comprising (i ) a first interesterified intermediate, which is the reaction product of a mono- and/or di-ester derivative of TPA and a comonomer, and essentially free of (ii) a second interesterified intermediate, which is the reaction product of an ester derivative of FDCA and a comonomer, and polymerization of the interesterified intermediate composition by means of polycondensation of the first transesterified intermediate to form a polyester product 262 comprising a polyester having terephthalate moieties and substantially free of furandicarboxylate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 302. After (B), the methods may further comprise reacting the stabilized esterified fraction 222 with a comonomer 24 having at least two hydroxyl groups (e.g., a diol) to form a stabilized transesterified intermediate (prepolymer) composition comprising (i) a first transesterified intermediate, being the reaction product of a mono- and/or di-ester derivative of TPA and a comonomer, and essentially free of (ii) a second interesterified intermediate product, which is the reaction product of an ester derivative of FDCA and a comonomer, and polymerization of the stabilized interesterified intermediate composition by polycondensation of the first interesterified intermediate product to provide a polyester product 262 comprising a polyester having terephthalate moieties and substantially free of furandicarboxylate moieties. The steps of reacting with comonomer 24 followed by polymerization via polycondensation are sub-steps of polymer formation 302.

In FIG. 3 shows embodiments of the present invention relating to methods for modifying (eg retrofitting) a technical installation or plant for the production of monomers and resulting apparatus/equipment. For example, a representative plant for the production of TPA may be built earlier and may, for example, operate below design capacity or be taken out of service altogether. The modification step can be used to restore overall profitability, or it can be used to improve the economics of the process as a result of the additional possibility of co-processing of the second accompanying monomer-forming feedstock, and in particular feedstock derived from renewable sources, in addition to para-xylene. In particular embodiments, the retrofitted TPA plant may include an oxidation reactor 205 configured to produce, as feedstocks, (i) para-xylene, such as in para-xylene-containing feedstock 14, and (ii ) oxygen, such as in the oxygenated feedstock 16. The TPA plant may also include a downstream TPA crystallization and recovery section 210 that is configured to separate and recycle the solvent 45 from this section back to the oxidation reactor 205. The modification may include retrofitting a TPA plant with a connection to an upstream carbohydrate dehydration reactor 100, such as using an existing oxidation reactor 205 inlet, such as a para-xylene containing feed 14 inlet, in accordance with the dotted arrows in FIG. 3, with the connection of the dehydration product 12 or its purified part 12' (eg after removal of humins) to this inlet. Otherwise, the connection may be provided by an additional input, according to the solid arrows in FIG. 3 connecting the dehydration product 12 or its purified part 12' directly to the oxidation reactor 205. The outlet of the oxidation reactor 205 may be configured to supply (eg, flow) an oxidizing effluent 18', such as containing FDCA and TPA and/or other monomers, to the TPA crystallization and recovery section 210, which, after retrofitting, may be configured to provide ( for example, flow) composition based on a mixture of monomers 18, as described above, with a reduced amount of solvent compared to the drain 18' or essentially free of solvent. The modification may further include configuring the TPA plant to provide (eg, stream or recycle) the solvent 45 or at least a portion of it 45' back to the dehydration reactor 100.

Where reference is made herein to the use of particular transition metal salts in the metal catalysts used in the process of the present invention, then said salts may be used in their hydrated, hemihydrate or unhydrated form in the formation of the metal catalysts. For example, in cases where cobalt (II) acetate is used, then the form of cobalt (II) acetate used in the preparation of the metal-containing catalysts used in the process of the present invention may be Co(OAc) 2 (non-hydrated), Co(OAc) 2.xH2O (semihydrated), Co(OAc)2.4H2O (hydrated). This also applies to other cobalt(II) salts that may be used, such as, for example, cobalt(II) bromide, cobalt(II) oxalate and other cobalt(II) salts known to those skilled in the art for use in such oxidation processes. For example, the form of manganese (II) acetate used in the preparation of the metal-containing catalysts used in the process of the present invention may be Mn(OAc)2 (non-hydrated), Mn(OAc)2,.xH2O (semi-hydrated), Mn(OAc) 2.4H2O (hydrated). This also applies to other manganese(II) salts known to those skilled in the art for use in such oxidation processes. This applies equally to additional metal compounds present in metal-containing catalysts (for example, cerium (III) acetate, zirconium (IV) acetate, etc.).

The following examples are presented as representative of the present invention. These examples are illustrative and should not be construed as limiting the scope of the present invention as defined in the appended claims.

EXAMPLES

Influence of Small Amounts of Associated Raw Materials on the Oxidation of Furan Compounds Forming FDCA

Experiments were carried out to evaluate the effect of xylenes as co-feedstock species for the oxidation of furan compounds forming FDCA, namely furan "co-compounds" HMF, 5-(acetoxymethyl)furfural (AcMF) and HMF dimer, which are the products obtained as a result of the dehydration of fructose in the presence of a solvent system of acetic acid and water. The dehydration product used in each experiment contained 8.5% by weight of these compounds in solution with this solvent system. The oxidation reactor used for the experiments was loaded in each case with a homogeneous catalyst composition containing cobalt, manganese and bromine in concentrations of 4740 wt. ppm, 885 wt. ppm and 1475 wt. ppm, respectively. Oxidation reaction conditions provided for a temperature of 180° C. and a total pressure of 15.2 bar (220 psi, 1.52 MPa), while the values of the dehydration product and air feed into the oxidation reactor were maintained at 0.9 milliliters per minute (ml/min) and 550 standard cubic centimeters per minute (sccm), with a target reaction time of 60 minutes. This target reaction time was precisely the maximum time that the reaction was carried out in each experiment, with the potential for shorter reaction times to result in "light out" events as indicated by a drop in oxygen consumption. After each reaction, the oxidation reactor contents were analyzed to determine the amounts of FDCA present as well as the amounts of FDCA-forming intermediates such as 5-hydroxymethyl-2-furoic acid and 5-formyl-2-furoic acid, which nevertheless are valuable reaction products in terms of their ability to undergo further oxidation to form FDCA.

The specific reaction protocol used was as follows.

A 300 ^cc titanium batch reactor equipped with a gas dispersion impeller supplied by Parr was charged with 70 g of acetic acid, 3.75 g of water, 0.233 g of HBr solution (48 wt% HBr in water), 0.888 g of Co (OAc) ² ⋅4H2O and 0.175 g Mn(OAc) ² ⋅4H2O, then sealed and pressurized with nitrogen to about 100 psi (0.69 MPa) before heating to 180°C with stirring at 1200 rpm. The reactor was pressurized with a back pressure regulator (BPR) set at 220 psi (1.52 MPa). After the temperature had been reached, air was introduced into the reactor at a rate of 550 standard cubic centimeters per minute (SCCM) and the effluent gas from the BPR was monitored to determine when the oxygen content of the dry gas in the reactor stabilized. When oxygen stabilized, furan was fed into the reactor at a rate of 0.9 ml/min to initiate the reaction. Waste oxygen was monitored throughout the process, and if oxygen consumption abruptly stopped, the feed was stopped and the reaction was quenched by rapidly cooling the reactor in an ice bath. Otherwise, the reaction was allowed to proceed for 60 minutes, after which the supply of raw materials was stopped and immediately extinguished. After the reaction, the furan species in the liquid and solid products were analyzed by UPLC.

The furan feedstock used in the above procedure was obtained by slightly modifying the crude liquid product of the fructose dehydration reaction. In particular, a mixture of 19 wt.% fructose, 0.6 wt.% glucose, 7.7 wt.% water and 2 mol. % HBr (relative to total sugar) in acetic acid was fed into a continuous reactor with an internal average temperature of 160° C. and a liquid residence time of 1.695 minutes. System pressure was maintained at 200 psig (1.38 MPa, gauge) with a back pressure regulator. The dehydration product was collected and stored until used as a raw material for oxidation.

As analyzed, the dehydration product, prior to the addition of additional solvent or related feedstock, contained 4.77 wt% HMF, 3.89 wt% 5-(acetoxymethyl)furfural (AcMF), 0.15 wt% HMF dimer, 13.63 % water and 1542 ppm Br (as HBr) with the remainder as acetic acid and other fructose dehydration by-products. To obtain raw materials based on compounds of the furan series for oxidation, aromatic accompanying raw materials (if present - see below), acetic acid and water were added so that the final total content of accompanying furan compounds was 8.5 wt.%, the concentration of water was 14.75 wt.%, and the content of associated raw materials (if present) was 1.77 wt.% of the total weight of the raw materials based on compounds of the furan series.

An initial experiment was conducted using a dehydration product feedstock ("furan feedstock") containing no aromatic co-feedstock as described above, and three (3) separate further experiments were conducted using this feedstock but with added quantities of co-feedstock species. (i) para-xylene, according to experiment A, (ii) ortho-xylene, according to experiment B, and (iii) mixed xylenes, according to experiment C. The amounts added in each case were about 40 mol. % of the total number of furan compounds forming FDCA. Compared to the initial experiment, in which the selectivity of the converted furan compounds forming FDCA in FDCA was about 60 mol. %, in experiments A-C, this selectivity was increased to 65-69 mol. %. In addition, the overall selectivity for FDCA and FDCA-forming intermediates in the initial experiment was just over 80 mol %. %, while in experiments A-C this selectivity was increased to 84-87 mol. %. Accordingly, the addition of each of the three co-feedstocks resulted in an improvement in the performance of the homogeneously catalyzed oxidation of FDCA-forming furan compounds to FDCA.

Importantly, however, the initial experiment was run for only about 52 minutes, after which the reaction light was turned off and no further conversion occurred. In contrast, in Experiment B, the reaction can be maintained up to the target reaction time of 60 minutes, and in Experiments A and C, the light out/oxygen consumption continued even after this target reaction time had elapsed. Accordingly, each of the three co-feedstocks, and para-xylene and mixed xylenes in particular, advantageously exhibited a stabilizing effect on the oxidation of FDCA-forming furan compounds to FDCA.

Co-oxidation of n-xylene and FDCA-forming furan compounds with Co, Mn, Br catalysts. A solution of the accompanying furan compounds was prepared by heating 218 gm of a mixture of 33 wt.% corn syrup (containing 76.25 wt.% fructose, 0.96 wt.% dextrose and 22.71 wt.% water), enough water to the total water content was 7.53 wt.%, with 2.0 mol. % HBr relative to the total amount of fructose and glucose and the rest in the form of acetic acid up to 155 deg. With a titanium reactor with a volume of 300 ml was subjected to a pressure of 220 psig (1.52 MPa, excess) nitrogen. Immediately after reaching a temperature of 155 degrees. The reaction was quenched in an ice bath to stop the reaction. This dehydration product was diluted with acetic acid, water and p-xylene and used to dissolve the oxidation catalyst components comprising cobalt acetate tetrahydrate, manganese acetate tetrahydrate and hydrobromic acid so that the feed composition met the targets listed in Table 1.

The oxidation reactions were carried out on a semi-batch basis using a 300 ml titanium batch reactor equipped with a gas dispersion impeller supplied by Parr. The reactor was initially charged with 75 gm acetic acid, water, cobalt acetate tetrahydrate, manganese acetate tetrahydrate, and hydrobromic acid such that the feed composition met the target initial concentrations listed in Table 1. It was then sealed and injected with nitrogen at a pressure of approximately 100 psi ( 0.69 MPa) before heating to 180°C with stirring at 1200 rpm. The reactor was pressurized with a back pressure regulator (BPR) set at 220 psi (1.52 MPa). After the temperature had been reached, air was introduced into the reactor at a rate of 550 standard cubic centimeters per minute (SCCM) and the effluent gas from the BPR was monitored to determine when the oxygen content of the dry gas in the reactor stabilized. When the oxygen was stabilized, a furan compound feedstock was injected into the reactor at a predetermined ml/min rate to initiate the reaction. The reactions were allowed to proceed for the target time shown in Table 1, after which the feed was stopped and the reaction was allowed to proceed without additional substrate for the target time after oxidation shown in Table 1. Reactions with "light out" as described in the previous section , did not have. After the reaction, the furan species in the liquid and solid products were analyzed by UPLC. For reactions with 20% p-xylene in the feed, the furan compounds and p-xylene were fed by two separate pumps with a total flow rate as shown in the diagram.

Obtaining accompanying compounds of the furan series in a solvent containing acetic acid, p-xylene, water

The preparation of accompanying furan compounds in a mixture of acetic acid, p-xylene and water was also demonstrated. Replacing part of the acetic acid solvent in the sugar dehydration reaction with p-xylene facilitates the simplification of the integrated process for the production of terephthalic acid and FDCA and reduces the cost of acetic acid. In these examples, 207 g of a mixture of 33 wt.% corn syrup (containing 76.25 wt.% fructose, 0.96 wt.% dextrose and 22.71 wt.% water), enough water to have a total water content of 7 .53 wt.%, 2.36 mol. % HBr relative to the total content of fructose and glucose, specified wt.% p-xylene, as in table 2, and the rest in the form of acetic acid up to 155 deg. With a titanium reactor with a volume of 300 ml was subjected to a pressure of 220 psig (1.52 MPa, excess) nitrogen. Immediately after reaching a temperature of 155 degrees. The reaction was quenched in an ice bath to stop the reaction. The reaction products were analyzed by UPLC and the overall yields of the accompanying furan compounds were as indicated. p-Xylene appears to have little effect on dehydration at 2 wt.% and 5 wt.%, and possibly beneficial at about 20 wt.%.

Co-oxidation of p-xylene and HMF using different catalyst systems

Various catalyst systems were evaluated for their ability to simultaneously oxidize HMF and p-xylene to FDCA and terephthalic acid, respectively. All reactions were carried out with 0.2 M p-xylene and 0.2 M HMF. The various catalysts and additives and their amounts are shown in Figures 4 and 5, which show Tables 3 and 4. Reactions were carried out in glass vials placed in a 24-well, common head space plate reactor originally supplied by Freeslate. After all solids/liquids were added to the vials, the reactor was sealed, pressurized to 1000 psi (6.9 MPa) 5% oxygen in N2, then heated to 100 deg. C for 16 h with shaking. After cooling and depressurizing, the contents of the vials were dissolved in excess DMSO and analyzed for TPA and FDCA by HPLC. Reactions with a yield of more than 1 mol. % TPA or FDCA under these conditions were found to be active in oxidizing p-xylene or HMF to the corresponding carboxylic acids. Figure 4 shows a table. In the table in figure 4, OAc means acetate, acac means acetylacetonate, NHPI means N-hydroxyphthalimide, and mol. % refers to the combined moles of HMF and p-xylene. Figure 5 also shows a table. The table in Figure 5 lists the heterogeneous catalysts that were typically purchased from Johnson Matthey and are identified by catalog number, except for Au/TiO, which was provided by STREM and ground to a fine powder.

ITEMS

1. A method for preparing a composition based on a mixture of monomers containing 2,5-furandicarboxylic acid (FDCA) and terephthalic acid (TRA), wherein the method includes bringing the raw material for oxidation, in the presence of oxygen, into contact with an oxidation catalyst to obtain a composition based on mixtures of monomers, where

the feedstock for oxidation comprises (i) a dehydration product of one or more carbohydrates having a 6-carbon sugar unit, and (ii) para-xylene.

2. The method according to paragraph 1, where para-xylene is at least 1 wt.% of the total amount of (i) and (ii).

3. The method according to any of the preceding paragraphs, where para-xylene is from 1 wt.% to 75 wt.% of the total amount of (i) and (ii).

4. The method according to any of the preceding paragraphs, where para-xylene is from 2 wt.% to 45 wt.% of the total amount of (i) and (ii).

5. The method according to any one of the preceding paragraphs, where para-xylene is from 5 wt.% to 35 wt.% of the total amount of (i) and (ii).

6. The method according to any of the preceding paragraphs, where the specified (ii) para-xylene is present in an amount of less than 50 mol. %, preferably less than 45 mol. %, relative to 100 mol. % of said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

7. The method according to any of the previous paragraphs, where the specified (ii) para-xylene is present in an amount of 5 mol. % up to 45 mol. % relative to 100 mole % of said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

8. The method according to any of the previous paragraphs, where the specified (ii) para-xylene is present in an amount of 10 mol. % up to 80 mol. % relative to 100 mol. % of said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

9. The method according to any of the preceding paragraphs, where the specified (ii) para-xylene is present in an amount of 30 mol. % up to 60 mol. % relative to 100 mol. % of said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

10. The method according to any of the previous paragraphs, where the specified (ii) para-xylene is present in an amount of 85 mol. % up to 200 mol. % relative to 100 mol. % of said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

11. The method according to any of the previous paragraphs, where the specified (ii) para-xylene is present in an amount of 90 mol. % up to 150 mol. % relative to 100 mol.% of the specified (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

12. The method according to any of the previous paragraphs, where the specified (ii) para-xylene is present in an amount ranging from 100 mol. % up to 125 mol. % relative to 100 mol. % of said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

13. The method according to any one of the preceding claims, wherein said (ii) para-xylene is present in a molar amount greater than said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

14. The method according to any one of the preceding claims, wherein said (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit is present in a molar amount greater than said (ii) para-xylene.

15. The method according to any of the preceding paragraphs, wherein said one or more carbohydrates having a 6-carbon sugar unit is selected from the group consisting of starch, amylose, galactose, cellulose, hemicellulose, inulin, fructan, glucose, fructose, sucrose, maltose , cellobiose, lactose, sugar oligomers and any combination thereof.

16. The method according to any one of the preceding claims, wherein said one or more carbohydrates having a 6-carbon sugar unit is selected from hexose sugars.

17. The method according to any one of the preceding claims, wherein said one or more carbohydrates having a 6-carbon sugar unit is fructose.

18. The method according to any one of the preceding claims, wherein the dehydration product comprises 5-hydroxymethylfurfural (HMF) and/or an ester or ether derivative thereof.

18a. The process according to any one of the preceding claims, wherein the dehydration product is 5-hydroxymethylfurfural (HMF) and/or an ester or ether derivative thereof.

19. The method according to any one of the preceding claims, wherein the dehydration product comprises 5-hydroxymethylfurfural (HMF).

19a. The method according to any one of the preceding claims, wherein the dehydration product is 5-hydroxymethylfurfural (HMF).

20. The method according to any one of the preceding claims, wherein the dehydration product comprises an ester derivative of 5-hydroxymethylfurfural (HMF).

20a. The method according to any one of the preceding claims, wherein the dehydration product is an ester derivative of 5-hydroxymethylfurfural (HMF).

21. The method according to any one of paragraphs 18, 18a, 20 or 20a, wherein said 5-hydroxymethylfurfural (HMF) ester derivative is 5-(acetoxymethyl)furfural.

22. The method according to any one of the preceding claims, wherein the dehydration product comprises an ether derivative of 5-hydroxymethylfurfural (HMF).

22a. The method according to any one of the preceding claims, wherein the dehydration product is an ether derivative of 5-hydroxymethylfurfural (HMF).

23. The method according to any one of paragraphs 18, 18a, 22 or 22a, wherein said 5-hydroxymethylfurfural (HMF) ester derivative is 5-(methoxymethyl)furfural.

24. The method according to any one of the preceding claims, wherein said dehydration product of one or more carbohydrates having a 6-carbon sugar unit is obtained in a preceding process step, said preceding process step comprising providing a dehydration feed comprising said one or more carbohydrates having 6-carbon sugar unit, and dehydration of said one or more carbohydrates having a 6-carbon sugar unit.

25. The process of claim 24, wherein said dehydration feed has a dry solids concentration of 5 wt% to 50 wt%, preferably 10 wt% to 30 wt%.

26. The method according to any one of paragraphs 24 or 25, wherein said dehydration feedstock is an aqueous solution of fructose.

27. The method according to any one of paragraphs 24-26, where the specified raw material for dehydration is an aqueous solution of fructose containing from 5 wt.% to 50 wt.%, preferably from 10 wt.% to 30 wt.% fructose, based on total weight specified raw material for dehydration.

28. The process according to claim 26 or 27, wherein said fructose has a purity of at least 90% by weight, preferably at least 97% by weight.

29. The method according to any one of paragraphs 24-28, where the specified stage of providing dehydration is carried out in the presence of a source of bromine.

30. The method of claim 29, wherein said bromine source is selected from the group consisting of hydrogen bromide, hydrobromic acid, sodium bromide, potassium bromide, molecular bromine, benzyl bromide, tetrabromoethane, 1-alkylpyridinium bromides, and 1,3-dialkylimidazolium bromides.

31. The method according to any one of paragraphs 29 or 30, wherein said source of bromine is hydrogen bromide.

32. The method according to any one of items 24-31, wherein said dehydration step is carried out in a solvent containing acetic acid.

33. The method according to any one of items 24-32, wherein said step of providing dehydration is carried out in a solvent containing water.

34. The method according to any one of items 24-33, wherein said dehydration step is carried out in a solvent containing acetic acid and water.

35. The method according to any one of paragraphs 24-34, where the specified stage of providing dehydration is carried out in a solvent containing alcohol.

36. The method of claim 35, wherein said alcohol is selected from the group consisting of methanol, ethanol, dioxane, and any combination thereof.

37. The method according to any one of paragraphs 24-36, where the specified stage of providing dehydration is carried out in a solvent containing (ii) p-xylene.

38. The process according to any one of the preceding claims, wherein the oxidation feed further comprises one or more humins.

39. A method according to any one of the preceding claims, wherein the oxygen source contacted by the oxidizing feedstock is air.

40. A process according to any one of the preceding claims, wherein the source of oxygen contacted by the oxidizing feedstock is purified oxygen.

41. The method according to any one of the preceding claims, wherein the oxidation catalyst is a homogeneous oxidation catalyst.

42. The method according to any one of the preceding claims, wherein the oxidation catalyst is a metal-containing catalyst.

43. The method according to any one of the preceding claims, wherein the oxidation catalyst comprises one or more transition metals.

44. The process according to any one of the preceding claims, wherein the oxidation catalyst comprises Co.

45. The process according to any one of the preceding claims, wherein the oxidation catalyst comprises Mn.

46. The process according to any one of the preceding claims, wherein the oxidation catalyst comprises Co and Mn.

47. The method according to any one of the preceding claims, wherein the oxidation catalyst provides Co in the form of Co(II).

48. The method according to any of the preceding claims, wherein the oxidation catalyst provides Co in the form of cobalt (II) acetate.

49. The process according to any one of the preceding claims, wherein the oxidation catalyst provides Co in the form of cobalt(II) bromide.

50. The method according to any one of the preceding claims, wherein the oxidation catalyst provides Co in the form of cobalt (II) oxalate.

51. The method according to any one of the preceding claims, wherein the oxidation catalyst provides Mn in the form of Mn(II).

52. The method according to any one of the preceding claims, wherein the oxidation catalyst provides Mn in the form of manganese(II) acetate.

53. The method according to any one of the preceding claims, wherein the oxidation catalyst provides Mn in the form of manganese (II) bromide.

54. The method according to any one of the preceding claims, wherein the oxidation catalyst provides Mn in the form of manganese (II) oxalate.

55. The method according to any one of paragraphs 44-54, where the oxidation catalyst further provides Zr.

56. The method according to item 55, wherein said Zr is Zr(IV).

57. The method according to item 56, wherein said Zr(IV) is Zr(IV) acetate.

58. The method according to any one of items 44-57, wherein the oxidation catalyst further provides Ce.

59. The method of claim 58 wherein said Ce is Ce(III).

60. The method according to item 59, wherein said Ce(III) is Ce(III) acetate.

61. The method according to any one of paragraphs 44-60, where the oxidation catalyst further provides Br.

62. The method according to any one of the preceding claims, wherein the oxidation feed comprises at least one bromine-containing material.

63. The method according to paragraph 62, where the specified at least one bromine-containing material is selected from the group consisting of inorganic bromides such as HBr; metal bromides such as lithium bromide, sodium bromide, potassium bromide, magnesium bromide, calcium bromide, cobalt bromide and manganese bromide; organic bromides such as 5-(bromomethyl)furfural and its derivatives and brominated furan oligomers; and any combination of any of them.

64. The method according to any one of items 62-63, wherein at least one bromine-containing material in the oxidation feed comes from a dehydration providing step.

65. The method according to any one of items 62-64, wherein the oxidation step introduces an additional source of bromine in addition to the bromine-containing material species present in the oxidation feed.

66. The method according to paragraph 65, where the specified additional source of bromine is selected from the group consisting of inorganic bromides such as HBr; metal bromides such as lithium bromide, sodium bromide, potassium bromide, magnesium bromide, calcium bromide, cobalt bromide and manganese bromide; organic bromides such as 5-(bromomethyl)furfural and its derivatives and brominated furan oligomers; and any combination of any of them.

67. The method according to any one of paragraphs 43-66, where the values of the concentration of one or more transition metals in the oxidation catalyst are independently in the range of 5 wt. ppm up to 10000 weight, ppm, based on the total weight of the oxidizing reaction mixture.

68. The method according to any one of paragraphs 43-67, where the values of the concentration of one or more transition metals in the oxidation catalyst are independently in the range from 10 wt. ppm up to 8000 wt. ppm based on the total weight of the oxidizing reaction mixture.

69. The method according to any one of paragraphs 43-68, where the values of the concentration of one or more transition metals in the oxidation catalyst are independently in the range of 50 wt. ppm up to 5000 wt. ppm based on the total weight of the oxidizing reaction mixture.

70. The method according to any of the previous paragraphs, where Co is present in the oxidizing reaction mixture at a concentration of 10 wt. ppm up to 10000 wt. ppm based on the total weight of the oxidizing reaction mixture.

71. The method according to any of the previous paragraphs, where Co is present in the oxidizing reaction mixture at a concentration of 10 wt. ppm up to 8000 wt. ppm based on the total weight of the oxidizing reaction mixture.

72. The method according to any of the previous paragraphs, where Co is present in the oxidizing reaction mixture in a concentration of 59 wt. ppm up to 5900 wt. ppm based on the total weight of the oxidizing reaction mixture.

73. The method according to any of the previous paragraphs, where Co is present in the oxidizing reaction mixture at a concentration of 2000 wt. ppm up to 4000 wt. ppm based on the total weight of the oxidizing reaction mixture.

74. The method according to any of the previous paragraphs, where Mn is present in the oxidizing reaction mixture in a concentration of 5 wt. ppm up to 10000 wt. ppm based on the total weight of the oxidizing reaction mixture.

75. The method according to any of the previous paragraphs, where Mn is present in the oxidizing reaction mixture in a concentration of 5 wt. ppm up to 8000 wt. ppm based on the total weight of the oxidizing reaction mixture.

76. The method according to any of the previous paragraphs, where Mn is present in the oxidizing reaction mixture in a concentration of 55 wt. ppm up to 5500 wt. ppm based on the total weight of the oxidizing reaction mixture.

77. The method according to any of the previous paragraphs, where Mn is present in the oxidizing reaction mixture in a concentration of 200 wt. ppm up to 1000 wt. ppm based on the total weight of the oxidizing reaction mixture.

78. The method according to any of the previous paragraphs, where Br is present in the oxidizing reaction mixture in a concentration of 0.1 wt. ppm up to 20000 wt. ppm based on the total weight of the oxidizing reaction mixture.

79. The method according to any of the previous paragraphs, where Br is present in the oxidizing reaction mixture in a concentration of 200 wt. ppm up to 20000 wt. ppm based on the total weight of the oxidizing reaction mixture.

80. The method according to any of the previous paragraphs, where Br is present in the oxidizing reaction mixture in a concentration of 10 wt. ppm up to 10000 wt. ppm based on the total weight of the reaction mixture.

81. The method according to any of the previous paragraphs, where Br is present in the oxidizing reaction mixture in a concentration of 1000 wt. ppm up to 2000 wt. ppm based on the total weight of the reaction mixture.

82. The method according to any one of items 78-81, wherein said Br is derived from said bromine-containing material species and/or said bromine source.

83. The method according to any of the previous paragraphs, where the amount of Co in the oxidizing reaction mixture is from 1 to 50 mol. % relative to 100 mol. %

(i) a dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

84. The method according to any of the previous paragraphs, where the amount of Co in the oxidizing reaction mixture is from 2 to 30 mol. % relative to 100 mol. % (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

85. The method according to any of the previous paragraphs, where the amount of Co in the oxidizing reaction mixture is from 10 to 20 mol. % relative to 100 mol. % (i) dehydration product of one or more carbohydrates having a 6-carbon sugar unit.

86. The method according to any one of the preceding claims, wherein the molar ratio of Co:Mn in the oxidizing reaction mixture is from 1:1 to 100:1.

87. The method according to any one of the preceding claims, wherein the molar ratio of Co:Mn in the oxidizing reaction mixture is from 1:1 to 10:1.

88. The method according to any one of the preceding claims, wherein the molar ratio of Co:Mn in the oxidizing reaction mixture is from 3:1 to 6:1.

89. The method according to any one of the preceding claims, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:100 to 10:1.

90. The method according to any one of the preceding claims, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:50 to 5:1.

91. The method according to any one of the preceding claims, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:20 to 1.5:1.

92. The method according to any one of the preceding claims, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:5 to 1:1.

93. A method according to any of the preceding paragraphs, wherein said bringing the oxidation feed, in the presence of oxygen, into contact with an oxidation catalyst to obtain a composition based on a mixture of monomers is carried out at a temperature of from 120 ° C to 250 ° C.

94. The method according to any one of the preceding paragraphs, wherein said bringing the oxidation feed, in the presence of oxygen, into contact with an oxidation catalyst to obtain a composition based on a mixture of monomers is carried out at a temperature of from 170 ° C to 190 ° C.

95. The method according to any one of the preceding claims, wherein the oxygen partial pressure in said contact of the oxidation feedstock, in the presence of oxygen, with an oxidation catalyst to form a composition based on a mixture of monomers is from 0.02 bar to 100 bar.

96. The method according to any one of the preceding claims, wherein the oxygen partial pressure in said bringing the oxidation feed, in the presence of oxygen, into contact with an oxidation catalyst to form a composition based on a mixture of monomers is from 0.02 bar to 21 bar.

97. The method according to any one of the preceding claims, wherein the partial pressure of oxygen in said bringing the oxidation feed, in the presence of oxygen, into contact with an oxidation catalyst to form a composition based on a mixture of monomers is from 0.2 bar to 100 bar.

98. The method according to any one of the preceding claims, wherein the partial pressure of oxygen in said bringing the oxidation feed, in the presence of oxygen, into contact with an oxidation catalyst to form a composition based on a mixture of monomers is from 0.2 bar to 21 bar.

99. A process according to any one of the preceding claims, wherein the total absolute pressure for said bringing the oxidizing feed, in the presence of oxygen, into contact with an oxidizing catalyst to form a composition based on a mixture of monomers is between 1 bar and 200 bar.

100. The method according to any one of the preceding claims, wherein the total absolute pressure for said bringing the oxidizing feed, in the presence of oxygen, into contact with an oxidizing catalyst to form a composition based on a mixture of monomers is from 5 bar to 100 bar.

101. The method according to any one of the preceding claims, wherein the total absolute pressure for said bringing the oxidizing feedstock, in the presence of oxygen, into contact with an oxidizing catalyst to form a composition based on a mixture of monomers is between 10 bar and 20 bar.

102. The method according to any one of the preceding claims, wherein said bringing the oxidation feed, in the presence of oxygen, into contact with an oxidation catalyst is carried out in the presence of a solvent.

103. The method according to item 102, wherein said solvent comprises acetic acid.

104. The method according to any one of paragraphs 102 or 103, wherein said solvent comprises water.

105. The method according to any one of paragraphs. 102-104, wherein said solvent comprises acetic acid and water.

106. The method according to any of the preceding paragraphs, where the specified bringing the raw material for oxidation, in the presence of oxygen, in contact with the oxidation catalyst to obtain a composition based on a mixture of monomers is carried out for a time sufficient to obtain a composition based on a mixture of monomers containing FDCA and TPA .

107. The method according to any one of the preceding claims, wherein said bringing the oxidation feed, in the presence of oxygen, into contact with an oxidation catalyst to form a composition based on a mixture of monomers is carried out over a period of time ranging from 15 minutes to 24 hours.

108. The method according to any one of paragraphs 1-107, further comprising

(A) color stabilization of the monomer mixture composition by adding a color stabilizing medium to the monomer mixture composition to obtain a stabilized composition containing FDCA and TPA; And

(B) optionally after (A) providing esterification of the stabilized composition by reacting the stabilized composition with an esterifying agent to obtain a stabilized, esterified composition containing ester derivatives of FDCA and TPA.

109. The method according to item 108, wherein the esterifying agent is methanol and the ester derivatives FDCA and TPA are 2,5-furandicarboxylic acid, dimethyl ether (FDME) and dimethyl terephthalate (DMT), respectively.

110. The method according to item 108 or item 109, further comprising the following (A)

reacting a stabilized composition containing FDCA and TPA with a comonomer having at least two hydroxyl groups to form a stabilized co-esterified intermediate composition containing (i) a first esterified intermediate resulting from the reaction of FDCA and comonomer, and (ii) a second an esterified intermediate which is the reaction product of TPA and comonomer, and

polymerizing the stabilized co-esterified intermediate composition by polycondensing the first and second esterified intermediates to form a copolymer product comprising a copolymer having furandicarboxylate moieties and terephthalate moieties,

or next (B)

reacting a stabilized esterified composition containing ester derivatives of FDCA and TPA with a comonomer having at least two hydroxyl groups to obtain a stabilized co-esterified intermediate composition containing (i) a first transesterified intermediate, which is the product of the reaction of an ester derivative of FDCA and a comonomer, and (ii) a second transesterified intermediate which is the reaction product of a TPA ester derivative and a comonomer, and

polymerizing the stabilized co-transesterified intermediate composition by polycondensing the first and second transesterified intermediates to form a copolymer product comprising a copolymer having furandicarboxylate moieties and terephthalate moieties.

111. The method according to any one of paragraphs 1-107, further comprising

(A) causing the monomer mixture composition to be esterified by reacting the monomer mixture composition with an esterifier to form an esterified monomer mixture composition containing ester derivatives of FDCA and TPA, and

(B) optionally after (A), stabilizing the color of the esterified monomer mixture composition by adding a color stabilizing medium to the esterified monomer mixture composition to form a stabilized esterified composition containing ester derivatives of FDCA and TPA.

112. The method according to item 111, wherein the esterifying agent is methanol and the ester derivatives FDCA and TPA are 2,5-furandicarboxylic acid, dimethyl ether (FDME) and dimethyl terephthalate (DMT), respectively.

113. The method according to item 111 or item 112, further comprising the following (A)

separating, by distillation, the esterified composition based on a mixture of monomers into a first fraction enriched in the ester derivative FDCA and a second fraction enriched in the ester derivative TPA,

or next (B)

separating, by distillation, the stabilized esterified composition into a first fraction enriched in the FDCA ester derivative and a second fraction enriched in the ester derivative TPA.

114. The method according to item 111 or item 112, further comprising the following (A)

reacting an esterified composition based on a mixture of monomers containing ester derivatives of FDCA and TPA with a comonomer having at least two hydroxyl groups to obtain a co-interesterified intermediate composition containing (i) a first transesterified intermediate, which is the reaction product of an ester derivative of FDCA and a comonomer, and (ii) a second transesterified intermediate which is the reaction product of a TPA ester derivative and a comonomer, and

polymerizing the co-transesterified intermediate composition by polycondensing the first and second esterified intermediates to form a copolymer product comprising a copolymer having furandicarboxylate moieties and terephthalate moieties,

or next (B)

reacting a stabilized esterified composition containing ester derivatives of FDCA and TPA with a comonomer having at least two hydroxyl groups to obtain a stabilized co-esterified intermediate composition containing (i) a first transesterified intermediate, which is the product of the reaction of an ester derivative of FDCA and a comonomer, and (ii) a second transesterified intermediate which is the reaction product of a TPA ester derivative and a comonomer, and

polymerizing the stabilized co-transesterified intermediate composition by polycondensing the first and second transesterified intermediates to form a copolymer product comprising a copolymer having furandicarboxylate moieties and terephthalate moieties.

115. The method according to any one of paragraphs 1-107, further comprising separating the composition based on a mixture of monomers into a first fraction enriched in FDCA, and a second fraction enriched in TPA.

116. The method according to paragraph 115, further comprising

(A) color stabilization of the first FDCA-enriched fraction by adding a color-stabilizing medium to obtain a stabilized FDCA-enriched fraction; And

(B) optionally after (A) providing esterification of the stabilized FDCA-enriched fraction by reaction with an esterifying agent to obtain a stabilized esterified FDCA-enriched fraction containing an ester derivative of FDCA.

117. The method according to item 116, wherein the esterifying agent is methanol and the FDCA ester derivative is 2,5-furandicarboxylic acid, dimethyl ether (FDME).

118. The method according to any one of paragraphs 116 or 117, further comprising the following (A)

reacting the stabilized FDCA-enriched fraction with a comonomer having at least two hydroxyl groups to produce a stabilized esterified intermediate composition containing (i) a first esterified intermediate resulting from the reaction of FDCA and comonomer, and substantially free of (ii) a second esterified intermediate which is the reaction product of TPA and comonomer, and

polymerizing the stabilized esterified intermediate composition by polycondensing the first esterified intermediate to form a copolymer product comprising a copolymer having furandicarboxylate moieties and substantially free of terephthalate moieties,

or next (B)

reacting a stabilized FDCA-enriched esterified fraction containing an FDCA ester derivative with a comonomer having at least two hydroxyl groups to obtain a stabilized transesterified intermediate composition containing (i) a first transesterified intermediate, which is the product of the reaction of the FDCA ester derivative and the comonomer, and substantially free of (ii) a second transesterified intermediate which is the reaction product of a TPA ester derivative and a comonomer, and

polymerizing the stabilized interesterified intermediate composition by polycondensing the first interesterified intermediate to form a copolymer product comprising a copolymer having furandicarboxylate moieties and substantially free of terephthalate moieties.

119. The method according to paragraph 115, further comprising

causing the first FDCA-rich fraction to be esterified by reacting with the esterifying agent to obtain an esterified FDCA-rich fraction containing the FDCA ester derivative, and

(B) optionally after (A) color stabilization of the esterified FDCA-enriched fraction by adding a color stabilizing medium to obtain a stabilized esterified FDCA-enriched fraction.

120. The method according to item 119, wherein the esterifying agent is methanol and the FDCA ester derivative is 2,5-furandicarboxylic acid, dimethyl ether (FDME).

121. The method according to any one of paragraphs 119 or 120, further comprising the following (A)

reacting an FDCA-enriched esterified fraction containing an FDCA ester derivative with a comonomer having at least two hydroxyl groups to obtain a transesterified intermediate composition comprising (i) a first transesterified intermediate, which is the reaction product of the FDCA ester derivative and the comonomer, and essentially not containing (ii) a second interesterified intermediate product, which is the product of the reaction of an ester derivative of TPA and a comonomer, and

polymerizing the interesterified intermediate composition by polycondensing the first interesterified intermediate to form a copolymer product comprising a copolymer having furandicarboxylate moieties and substantially free of terephthalate moieties,

or next (B)

reacting a stabilized esterified FDCA-enriched fraction with a comonomer having at least two hydroxyl groups to obtain a stabilized interesterified intermediate composition containing (i) a first interesterified intermediate that is the product of the reaction of an ester derivative of FDCA and a comonomer, and essentially free of (ii) a second transesterified intermediate which is the reaction product of a TPA ester derivative and a comonomer, and

polymerizing the stabilized interesterified intermediate composition by polycondensing the first interesterified intermediate to form a copolymer product comprising a copolymer having furandicarboxylate moieties and substantially free of terephthalate moieties.

122. The method according to paragraph 115, further comprising

(A) color stabilization of the second TPA-rich fraction by adding a color-stabilizing medium to obtain a stabilized TPA-rich fraction; And

(B) optionally after (A) providing esterification of the stabilized TPA-rich fraction by reaction with an esterifier to obtain a stabilized esterified TPA-rich fraction containing a TPA ester derivative.

123. The method according to item 122, wherein the esterifying agent is methanol and the TPA ester derivative is dimethyl terephthalate (DMT).

124. The method according to item 122 or item 123, further comprising the following (A)

reacting the stabilized TPA-enriched fraction with a comonomer having at least two hydroxyl groups to form a stabilized esterified intermediate composition containing (i) a first esterified intermediate resulting from the reaction of TPA and comonomer, and substantially free of (ii) a second esterified intermediate which is the reaction product of FDCA and comonomer, and

polymerizing the stabilized esterified intermediate composition by polycondensing the first esterified intermediate to form a copolymer product comprising a copolymer having terephthalate moieties and substantially free of furandicarboxylate moieties,

or next (B)

reacting a stabilized esterified fraction enriched in TPA containing an ester derivative of TPA with a comonomer having at least two hydroxyl groups to obtain a stabilized interesterified intermediate composition containing (i) a first interesterified intermediate, which is the product of the reaction of an ester derivative of TPA and a comonomer, and substantially free of (ii) a second transesterified intermediate which is the reaction product of an ester derivative of FDCA and a comonomer, and

polymerizing the stabilized interesterified intermediate composition by polycondensing the first interesterified intermediate to form a copolymer product comprising a copolymer having terephthalate moieties and substantially free of furandicarboxylate moieties,

125. The method according to paragraph 115, further comprising

causing a second TPA-rich fraction to be esterified by reaction with an esterifier to obtain an esterified TPA-rich fraction containing a TPA ester derivative, and

(B) optionally after (A) color stabilization of the TPA-rich esterified fraction by adding a color stabilizing medium to obtain a stabilized TPA-rich esterified fraction.

126. The method according to item 125, wherein the esterifying agent is methanol and the TPA ester derivative is dimethyl terephthalate (DMT).

127. The method according to item 125 or item 126, further comprising the following (A)

reacting an esterified TPA-rich fraction containing a TPA ester derivative with a comonomer having at least two hydroxyl groups to obtain a transesterified intermediate composition comprising (i) a first transesterified intermediate which is the reaction product of the TPA ester derivative and the comonomer, and essentially not containing (ii) a second interesterified intermediate product, which is the product of the reaction of an ester derivative of FDCA and a comonomer, and

polymerizing the interesterified intermediate composition by polycondensing the first interesterified intermediate to form a copolymer product comprising a copolymer having terephthalate moieties and substantially free of furandicarboxylate moieties,

or next (B)

reacting the stabilized TPA-enriched esterified fraction with a comonomer having at least two hydroxyl groups to obtain a stabilized interesterified intermediate composition containing (i) a first interesterified intermediate, which is the product of the reaction of an ester derivative of TPA and a comonomer, and essentially free of (ii) a second transesterified intermediate which is the reaction product of an ester derivative of FDCA and a comonomer, and

polymerizing the stabilized interesterified intermediate composition by polycondensing the first interesterified intermediate to form a copolymer product comprising a copolymer having terephthalate moieties and substantially free of furandicarboxylate moieties,

128. The method according to any one of items 108-114 or 116-127, wherein said color stabilizing medium comprises one or more substituted phenols.

129. The method according to paragraph 128, where the specified one or more substituted phenols are selected from the group consisting of methoxy-substituted phenols (for example, butylated hydroxyanisole (BHA); 2,6-dimethoxyphenol (DMP); 2,6-di-tert- butyl-4-methoxyphenol (DTMP)), tert-butyl-substituted phenols (e.g. pentaerythritol-tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate (PETC); 2-tert-butylhydroquinone (TBHQ ); ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate); octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)- propionate) and any combination of any of them.

130. The method according to any one of paragraphs 108-114, 116-127, 128, or 129, wherein said color stabilizing medium comprises one or more phenyl-substituted amines (e.g., 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (XDPA) ), one or more phosphites (eg, tris(2,4-di-tert-butylphenyl)phosphite), antioxidant vitamins (eg, ascorbic acid), or any combination thereof.

131. The method according to any one of items 108-114, 116-127 or 128-130, wherein said color stabilizing medium comprises a combination of one or more mpem-butyl-substituted phenols and one or more phosphites.

132. The method according to any one of items 108-114, 116-127, or 128-131, wherein said color stabilizing medium comprises 50% by weight of PETC and 50% by weight of tris(2,4-di-tert-butylphenyl)phosphite.

133. The method according to any one of paragraphs 108-114, 116-127 or 128-131, where the specified color stabilizing medium provides 20 wt.% octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 80% by weight tris(2,4-di-tert-butylphenyl)phosphite.

134. The method according to any one of paragraphs 110, 114, 117, 119, 124, 127, or 128-133, wherein said comonomer having at least two hydroxyl groups is a diol.

135. The method according to item 134, wherein said diol is selected from the group consisting of ethylene glycol, 1,3-propanol, isomannide, isosorbide, isoidide, furan-2,5-diol, furan-2,5-dimethanol, hydroquinone, benzene- 1,4-dimethanol and any combination thereof.

136. The method according to paragraph 134 or 135, where the specified diol provides an isoidide.

137. The method according to any one of items 134-136, wherein said diol is an isoidide.

138. A method for producing a composition based on a mixture of monomers containing 2,5-furandicarboxylic acid (FDCA) and terephthalic acid (TRA), while the method includes the joint supply of (i) compounds of the furan series forming FDCA, and (ii) para-xylene into an oxidation reactor containing an oxidation catalyst and reacting oxygen to form a composition based on a mixture of monomers.

139. The method according to paragraph 138, where para-xylene is from 1 wt.% to 75 wt.% of the total amount of (i) and (ii).

140. The method according to any one of paragraphs 138-139, where para-xylene is from 2 wt.% to 45 wt.% of the total amount of (i) and (ii).

141. The method according to any one of paragraphs 138-140, where para-xylene is from 5 wt.% to 35 wt.% of the total amount of (i) and (ii).

142. The method according to any one of paragraphs 138-141, where the specified (ii) para-xylene is present in an amount of less than 50 mol. %, preferably less than 45 mol. %, relative to 100 mol. % of the specified (i) compounds of the furan series, forming FDCA.

143. The method according to any one of paragraphs 138-142, where the specified (ii) para-xylene is present in an amount of 5 mol. % up to 45 mol. % relative to 100 mol. % of the specified (i) compounds of the furan series, forming FDCA.

144. The method according to any one of paragraphs 138-143, where the specified (ii) para-xylene is present in an amount of 10 mol. % up to 80 mol. % relative to 100 mol. % of the specified (i) compounds of the furan series, forming FDCA.

145. The method according to any one of paragraphs 138-144, where the specified (ii) para-xylene is present in an amount of 30 mol. % up to 60 mol. % relative to 100 mol. % of the specified (i) compounds of the furan series, forming FDCA.

146. The method according to any one of paragraphs 138-145, where the specified (ii) para-xylene is present in an amount of 85 mol. % up to 200 mol. % relative to 100 mol. % of the specified (i) compounds of the furan series, forming FDCA.

147. The method according to any one of paragraphs 138-146, where the specified (ii) para-xylene is present in an amount of 90 mol. % up to 150 mol. % relative to 100 mol. % of the specified (i) compounds of the furan series, forming FDCA.

148. The method according to any one of paragraphs 138-147, where the specified (ii) para-xylene is present in an amount of 100 mol. % up to 125 mol. % relative to 100 mol. % of the specified (i) compounds of the furan series, forming FDCA.

149. The method according to any one of items 138-148, wherein said (ii) para-xylene is present in a molar amount greater than the molar amount of said (i) FDCA-forming furan compounds.

150. The method according to any one of items 138-149, wherein said (i) FDCA-forming furan compounds are present in a molar amount greater than said (ii) para-xylene.

151. The method according to any one of items 138-150, wherein said (i) FDCA-forming furan compounds provide 5-hydroxymethylfurfural (HMF) and/or an ester or ester derivative thereof.

152. The method according to any one of items 138-151, wherein said (i) FDCA-forming furan compounds provide 5-hydroxymethylfurfural (HMF).

153. The method according to any one of items 138-152, wherein said (i) FDCA-forming furan compounds provide an ester derivative of 5-hydroxymethylfurfural (HMF).

154. The method of item 153, wherein said 5-hydroxymethylfurfural (HMF) ester derivative is 5-(acetoxymethyl)furfural.

155. The method according to any one of items 138-154, wherein said (i) FDCA-forming furan compounds provide an ester derivative of 5-hydroxymethylfurfural (HMF).

156. The method according to item 155, wherein said 5-hydroxymethylfurfural (HMF) ester derivative is 5-(methoxymethyl)furfural.

157. The method according to any one of items 138-156, wherein one or more humins are also present in the oxidation reactor.

158. The method according to any one of items 138-157, wherein the source of reactive oxygen is air.

159. The method according to any one of items 138-158, wherein the source of reactive oxygen is purified oxygen.

160. The method according to any one of items 138-159, wherein the oxidation catalyst is a homogeneous oxidation catalyst.

161. The method according to any one of items 138-160, where the oxidation catalyst is a metal-containing catalyst.

162. The method of any one of items 138-161, wherein the oxidation catalyst comprises one or more transition metals.

163. The method according to any one of items 138-162, where the oxidation catalyst provides Co.

164. The method according to any one of items 138-163, where the oxidation catalyst provides Mn.

165. The method according to any one of items 138-164, where the oxidation catalyst provides Co and Mn.

166. The method according to any one of items 138-165, where the oxidation catalyst provides Co in the form of Co(II).

167. The method according to any one of items 138-166, wherein the oxidation catalyst provides Co in the form of cobalt (II) acetate.

168. The method according to any one of items 138-167, wherein the oxidation catalyst provides Co in the form of cobalt (II) bromide.

169. The method according to any one of items 138-168, wherein the oxidation catalyst provides Co in the form of cobalt (II) oxalate.

170. The method according to any one of items 138-169, where the oxidation catalyst provides Mn in the form of Mn(II).

171. The method according to any one of items 138-170, wherein the oxidation catalyst provides Mn in the form of manganese (II) acetate.

172. The method according to any one of items 138-171, where the oxidation catalyst provides Mn in the form of manganese (II) bromide.

173. The method according to any one of items 138-172, where the oxidation catalyst provides Mn in the form of manganese (II) oxalate.

174. The method according to any one of items 163-173, where the oxidation catalyst further provides Zr.

175. The method according to paragraph 174, where the specified Zr represents Zr(IV).

176. The method of item 175 wherein said Zr(IV) is Zr(IV) acetate.

177. The method according to any one of items 163-176, where the oxidation catalyst further provides Ce.

178. The method of claim 177 wherein said Ce is Ce(III).

179. The method according to item 178, wherein said Ce(III) is Ce(III) acetate.

180. The method according to any one of paragraphs 138-179, where the oxidation catalyst further provides Br.

181. The method according to any one of items 138-180, where the source of bromine is fed into the reactor for oxidation.

182. The method according to paragraph 181, where the specified source of bromine is selected from the group consisting of inorganic bromides such as HBr; metal bromides such as lithium bromide, sodium bromide, potassium bromide, magnesium bromide, calcium bromide, cobalt bromide and manganese bromide; organic bromides such as 5-(bromomethyl)furfural and its derivatives and brominated furan oligomers; and any combination of any of them.

183. The method according to any one of paragraphs 162-182, where the values of the concentration of one or more transition metals in the oxidation catalyst are independently in the range of 5 wt. ppm up to 10000 wt. ppm based on the total weight of the oxidizing reaction mixture.

184. The method according to any one of paragraphs 162-183, where the values of the concentration of one or more transition metals in the oxidation catalyst are independently in the range from 10 wt. ppm up to 8000 wt. ppm based on the total weight of the oxidizing reaction mixture.

185. The method according to any one of paragraphs 162-184, where the values of the concentration of one or more transition metals in the oxidation catalyst are independently in the range of 50 wt. ppm up to 5000 wt. ppm based on the total weight of the oxidizing reaction mixture.

186. The method according to any one of paragraphs 138-185, where Co is present in the oxidizing reaction mixture at a concentration of 10 wt. ppm up to 10000 wt. ppm based on the total weight of the oxidizing reaction mixture.

187. The method according to any one of paragraphs 138-186, where Co is present in the oxidizing reaction mixture at a concentration of 10 wt. ppm up to 8000 wt. ppm based on the total weight of the oxidizing reaction mixture.

188. The method according to any one of paragraphs 138-187, where Co is present in the oxidizing reaction mixture at a concentration of 59 wt. ppm up to 5900 wt. ppm based on the total weight of the oxidizing reaction mixture.

189. The method according to any one of paragraphs 138-188, where Co is present in the oxidizing reaction mixture at a concentration of 2000 wt. ppm up to 4000 wt. ppm based on the total weight of the oxidizing reaction mixture.

190. The method according to any one of paragraphs 138-189, where Mn is present in the oxidizing reaction mixture at a concentration of 5 wt. ppm up to 10000 wt. ppm based on the total weight of the oxidizing reaction mixture.

191. The method according to any one of paragraphs 138-190, where Mn is present in the oxidizing reaction mixture at a concentration of from 5 wt. ppm up to 8000 wt. ppm based on the total weight of the oxidizing reaction mixture.

192. The method according to any one of paragraphs 138-191, where Mn is present in the oxidizing reaction mixture at a concentration of 55 wt. ppm up to 5500 wt. ppm based on the total weight of the oxidizing reaction mixture.

193. The method according to any one of paragraphs 138-192, where Mn is present in the oxidizing reaction mixture at a concentration of 200 wt. ppm up to 1000 wt. ppm based on the total weight of the oxidizing reaction mixture.

194. The method according to any one of paragraphs 138-193, where Br is present in the oxidizing reaction mixture at a concentration of from 0.1 wt. ppm up to 20000 wt. ppm based on the total weight of the oxidizing reaction mixture.

195. The method according to any one of paragraphs 138-194, where Br is present in the oxidizing reaction mixture at a concentration of 200 wt. ppm up to 20000 wt. ppm based on the total weight of the oxidizing reaction mixture.

196. The method according to any one of paragraphs 138-195, where Br is present in the oxidizing reaction mixture at a concentration of 10 wt. ppm up to 10000 wt. ppm based on the total weight of the reaction mixture.

197. The method according to any one of paragraphs 138-196, where Br is present in the oxidizing reaction mixture at a concentration of 1000 wt. ppm up to 2000 wt. ppm based on the total weight of the reaction mixture.

198. The method according to any one of paragraphs 138-197, where the amount of Co in the oxidizing reaction mixture is from 1 to 50 mol. % relative to 100 mol. % (i) compounds of the furan series, forming FDCA.

199. The method according to any one of paragraphs 138-198, where the amount of Co in the oxidizing reaction mixture is from 2 to 30 mol. % relative to 100 mol. % (i) compounds of the furan series, forming FDCA.

200. The method according to any one of paragraphs 138-199, where the amount of Co in the oxidizing reaction mixture is from 10 to 20 mol. % relative to 100 mol. % (i) compounds of the furan series, forming FDCA.

201. The method according to any one of paragraphs 138-200, where the amount of Co in the oxidizing reaction mixture is from 1 to 50 mol. % relative to 100 mol. % (i) compounds of the furan series, forming FDCA.

202. The method according to any one of items 138-201, wherein the molar ratio of Co:Mn in the oxidizing reaction mixture is from 1:1 to 100:1.

203. The method according to any one of items 138-202, wherein the molar ratio of Co:Mn in the oxidizing reaction mixture is from 1:1 to 10:1.

204. The method according to any one of items 138-203, wherein the molar ratio of Co:Mn in the oxidizing reaction mixture is from 3:1 to 6:1.

205. The method according to any one of items 138-204, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:100 to 10:1.

206. The method according to any one of items 138-205, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:50 to 5:1.

207. The method according to any one of items 138-206, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:20 to 1.5:1.

208. The method according to any one of items 138-207, wherein the molar ratio of Br:(all metals) in the oxidizing reaction mixture is from 1:5 to 1:1.

209. The method according to any one of paragraphs 138-208, where the oxidation reactor is operated under oxidizing conditions, including at a temperature of from 120 ° C to 250 ° C.

210. The method according to any one of paragraphs 138-209, where the oxidation reactor is operated under oxidizing conditions, including at a temperature of from 170 ° C to 190 ° C.

211. The method according to any one of items 138-210, wherein the oxidation reactor is operated under oxidizing conditions, including an oxygen partial pressure of 0.02 bar to 100 bar.

212. The method according to any one of items 138-211, wherein the oxidation reactor is operated under oxidizing conditions, including an oxygen partial pressure of 0.02 bar to 21 bar.

213. The method according to any one of paragraphs 138-212, where the oxidation reactor is operated under oxidizing conditions, including an oxygen partial pressure of 0.2 bar to 100 bar.

214. The method according to any one of paragraphs 138-213, where the oxidation reactor is operated under oxidizing conditions, including an oxygen partial pressure of 0.2 bar to 21 bar.

215. The method according to any one of paragraphs 138-214, where the oxidation reactor is operated under oxidizing conditions, including at a total absolute pressure of from 1 bar to 200 bar.

216. The method according to any one of paragraphs 138-215, where the oxidization reactor is operated under oxidizing conditions, including at a total absolute pressure of 5 bar to 100 bar.

217. The method according to any one of paragraphs 138-216, where the oxidation reactor is operated under oxidizing conditions, including at a total absolute pressure of from 10 bar to 20 bar.

218. The method according to any one of paragraphs 138-217, where the specified oxidation reactor additionally provides a solvent.

219. The method according to item 218, where the specified solvent provides acetic acid.

220. The method according to item 218 or item 219, where the specified solvent provides water.

221. The method of any one of items 218-220, wherein said solvent comprises acetic acid and water.

222. The method according to any one of items 138-221, wherein the oxidizing reactor is operated under oxidizing conditions for a time sufficient to produce a composition based on a mixture of monomers containing FDCA and TPA.

223. The method according to any one of items 138-222, where the oxidation reactor is operated under oxidizing conditions for a period of time ranging from 15 minutes to 24 hours.

224. The method according to any one of paragraphs 138-223, where the composition based on a mixture of monomers contains, as color-forming by-products, an aldehyde derivative of FDCA and an aldehyde derivative of TPA,

the method further comprising selectively hydrogenating one or both of the FDCA aldehyde derivative and the TPA aldehyde derivative.

225. The method according to item 224, wherein the aldehyde derivative of FDCA is 5-formyl-2-furancarboxylic acid (FFCA) and the aldehyde derivative of TPA is 4-carboxybenzaldehyde (4-CBA).

226. The method according to item 224 or item 225, wherein said selective hydrogenation of one or both of the FDCA aldehyde derivative and the TPA aldehyde derivative is performed after separation of the monomer mixture composition into an FDCA-rich fraction and a TPA-rich fraction.

227. The method according to any one of paragraphs 138-223, where the composition based on a mixture of monomers contains, as color-forming by-products, an aldehyde derivative of FDCA and an aldehyde derivative of TPA,

wherein the method further comprises, in the step of providing esterification of one or both of FDCA and TPA, obtaining, as additional color forming by-products, one or both of the aldehyde derivative of the ester derivative of FDCA and the aldehyde derivative of the ester derivative of TPA, and

the method further comprising selectively hydrogenating one or both of the FDCA ester aldehyde derivative and the TPA ester aldehyde derivative.

228. The method of claim 227 wherein the aldehyde derivative of the FDCA ester derivative is 5-formyl-2-furoic acid methyl ester (FFME) and the aldehyde derivative of the TPA ester derivative is 4-carboxybenzaldehyde methyl ester (4-CME).

229. The method according to item 227 or item 228, where the method includes providing esterification of FDCA and TPA at the stage of providing esterification of the composition based on a mixture of monomers by reacting the composition based on a mixture of monomers with an esterifying agent to obtain an esterified composition based on a mixture of monomers containing an aldehyde an ester derivative of FDCA; and an aldehyde derivative of an ester derivative of TPA.

230. The method of claim 229 wherein both FDCA and TPA are esterified before separating the esterified monomer mixture composition into a first fraction enriched in the FDCA ester derivative and a second fraction enriched in the TPA ester derivative.

231. The method according to item 228, where the esterification of one or both of FDCA and TPA is carried out at the stage of providing esterification of one or both of the FDCA-enriched fraction and the TPA-enriched fraction by reaction with an esterification agent after separating the composition based on a mixture of monomers into a fraction enriched in FDCA; and a fraction enriched in TPA.

232. The method according to any one of items 224-231, wherein said selective hydrogenation step comprises contacting said monomer mixture composition with hydrogen in the presence of a hydrogenation catalyst.

233. The method according to paragraph 232, where the specified hydrogenation catalyst provides Pt, Ru and Sn.

234. The method according to any one of items 138-233, wherein the co-feed includes providing FDCA-forming furan compounds and para-xylene as separate feed streams to the oxidation reactor.

235. The method of any one of items 138-233, wherein the co-feed comprises combining FDCA-forming furan compounds and para-xylene into a combined feed stream and providing the combined feed stream to an oxidation reactor.

236. The method according to any one of items 138-233, further comprising, prior to said co-feed, dehydrating one or more carbohydrates to form FDCA-forming furan compounds.

237. The method according to item 236, where the specified stage of providing dehydration is carried out in the presence of a source of bromine.

238. The method according to item 237, wherein said bromine source is selected from the group consisting of hydrogen bromide, hydrobromic acid, sodium bromide, potassium bromide, molecular bromine, benzyl bromide, tetrabromoethane, 1-alkylpyridinium bromides, and 1,3-dialkylimidazolium bromides.

239. The method according to any one of paragraphs 237 or 238, where the specified source of bromine is hydrogen bromide.

240. The method according to any one of paragraphs 237 or 238, where the specified source of bromine is hydrobromic acid.

241. The method according to any one of items 236-240, wherein said dehydration is carried out with said one or more carbohydrates in a solution containing a lower carboxylic acid or a lower alcohol.

242. The method of item 241 wherein said lower carboxylic acid is acetic acid.

243. The method of item 241 or item 242, wherein said alcohol is selected from the group consisting of methanol, ethanol, and any combination thereof.

244. The method according to any one of items 241-243, where the solution further provides para-xylene.

245. The method of item 244, wherein at least a portion of the para-xylene used in the dehydration step is unconverted para-xylene recovered from the monomer mixture composition after the oxidation step and reused in the dehydration step.

246. The method according to any one of items 236-245, wherein the dehydration is carried out with said one or more carbohydrates in a solution containing para-xylene and in the presence of an acid to catalyze the dehydration.

247. The method of item 246, wherein said dehydration catalysed acid is different from said lower carboxylic acid.

248. The method according to any one of paragraphs 246 or 247, where the specified acid to catalyze the dehydration is hydrobromic acid.

249. The method of item 246, wherein at least a portion of the para-xylene used in the dehydration step is unconverted para-xylene recovered from the monomer mixture composition after the oxidation step and reused in the dehydration step.

250. The method according to any one of items 236-249, wherein the oxidation catalyst comprises Co, Mn, and Br, and wherein, in addition, at least a portion of the Br is recovered, recycled, and fed to the dehydration providing stage.

251. The method of item 250 wherein at least a portion of the Br supplied to the dehydration step is in the form of hydrogen bromide.

252. The method according to item 251, wherein after said dehydration and before said co-feeding, the humic content of said FDCA-forming furan compounds is not reduced.

253. The method according to item 236, wherein after said dehydration and before said co-feeding, the humic content of said FDCA-forming furan compounds is not reduced.

254. The method according to any one of paragraphs 236-253, where one or more carbohydrates are selected from hexose sugars.

255. The method of any one of items 236-254, wherein said one or more carbohydrates is fructose.

256. The method according to any one of items 236-255, wherein said one or more carbohydrates is an aqueous solution of fructose.

257. The method according to any one of paragraphs 236-256, where the specified one or more carbohydrates is an aqueous solution of fructose containing from 5 wt.% to 50 wt.%, preferably from 10 wt.% to 30 wt.%, fructose, based from the total weight of the solution.

258. The method according to any one of paragraphs 255-257, where the specified fructose has a purity of at least 90 wt.%, preferably at least 97 wt.%.

259. A method for modifying a terephthalic acid (TPA) plant, wherein the production plant provides an oxidation reactor adapted to produce para-xylene and oxygen as feedstocks and further provides a subsequent section for crystallization and reduction of TPA, made with the possibility of separating solvent from TPA and recycling the solvent to the oxidation reactor,

the method comprising retrofitting said TPA plant with a compound from an existing oxidation reactor inlet or an additional oxidation reactor inlet to a downstream carbohydrate dehydration reactor.

Claims (16)

1. A method for preparing a composition based on a mixture of monomers containing 2,5-furandicarboxylic acid (FDCA) and terephthalic acid (TPA), the method comprising dehydration of one or more six-carbon carbohydrates to form FDCA-forming furan compounds, and co-feeding (i) FDCA-forming furan compounds and (ii) para-xylene to an oxidation reactor containing an oxidation catalyst and reacting oxygen to form a monomer mixture composition; Where said oxidation catalyst contains a Co or Mn compound, or a Co and Mn compound or compounds. 2. The method according to claim 1, where the composition based on a mixture of monomers contains, as color-forming by-products, an aldehyde derivative of FDCA and an aldehyde derivative of TPA, the method further comprising selectively hydrogenating one or both of the FDCA aldehyde derivative and the TPA aldehyde derivative. 3. The method of claim 2, wherein said selective hydrogenation of one or both of the FDCA aldehyde derivative and the TPA aldehyde derivative is performed after separating the monomer mixture composition into an FDCA-rich fraction and a TPA-rich fraction. 4. The method according to claim 1, where the composition based on a mixture of monomers contains, as color-forming by-products, an aldehyde derivative of FDCA and an aldehyde derivative of TPA, wherein the method further comprises, in the step of providing esterification of one or both of FDCA and TPA, obtaining, as additional color forming by-products, one or both of the aldehyde derivative of the ester derivative of FDCA and the aldehyde derivative of the ester derivative of TPA, and the method further comprising selectively hydrogenating one or both of the FDCA ester aldehyde derivative and the TPA ester aldehyde derivative. 5. The method of claim 4, wherein the method comprises providing esterification of both FDCA and TPA in a step of providing esterification of the monomer mixture composition by reacting the monomer mixture composition with an esterifying agent to produce an esterified monomer mixture composition containing an aldehyde. an ester derivative of FDCA; and an aldehyde derivative of an ester derivative of TPA. 6. The method of claim 4, wherein the esterification of one or both of FDCA and TPA is performed in the step of causing one or both of the FDCA-enriched fraction and the TPA-enriched fraction to be esterified by reacting with an esterifier after separating the mixture-based composition monomers per FDCA-enriched fraction and TPA-enriched fraction. 7. The method according to any one of paragraphs. 1-6, where co-feeding includes providing FDCA-forming furan compounds and para-xylene as separate feed streams to the oxidation reactor. 8. The method according to any one of paragraphs. 1-6 wherein co-feeding comprises combining FDCA-forming furan compounds and para-xylene into a combined feed stream and providing the combined feed stream to the oxidation reactor. 9. The method according to any one of paragraphs. 1-8, further comprising, prior to said co-feeding, providing dehydration of one or more carbohydrates in a solution containing a lower carboxylic acid or a lower alcohol to obtain FDCA-forming furan compounds in a mixture of crude dehydration products and providing FDCA-forming furan compounds, directly to the oxidation reactor along with para-xylene in a separate feed stream or in a combined feed stream. 10. The method of claim 9, wherein the solution further comprises para-xylene.

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