Improved reusable capture complex

Abstract

The present invention relates to the field of improved reusable capture complexes and methods of releasably capturing additives present in polymeric materials. The capture complexes comprise a catalyst entity, a magnetic nanoparticle, and a bridging moiety between only the catalyst entity and the magnetic nanoparticle. The uses and methods provide greatly reduced free additives in polymeric materials.

Description

[0001] This application is a divisional application of patent application No. 201580076798.0 filed on December 23, 2015, entitled "Improved Reusable Capture Complex". Technical Field

[0002] This invention relates to the field of improved reusable trapping complexes and methods for releasably trapping additives present in polymer materials. These uses and methods provide a significant reduction in free additives. Background Technology

[0003] A problem with many chemical processes is the interference of contaminants. Therefore, these contaminants are preferably removed before the process begins, i.e., the goal is to start with the purest possible source. However, if the contaminant is present in one of the source products to be processed, such as in a polymer material, removal is at least complex, and in some cases, almost impossible, such as when additives are present in the polymer. During the degradation of these polymers, the additives in the polymer material are released and may interfere with, for example, the degradation process and may cause side reactions. In this case, the additives are preferably removed during the degradation process, preferably continuously.

[0004] The interference from the additives under consideration involves interference with the catalyst. Generally, catalysts (especially complexes) and their function are highly sensitive to the presence of contaminants; in other words, they function properly under relatively pure and clean conditions. Because of contamination, catalysts need to be replaced periodically, and special care is usually required to avoid introducing contaminants. This may also be why catalysts are generally not considered for, for example, polymer degradation processes, as these methods almost inherently introduce contaminants in the form of additives present in the polymer material (e.g., curing agents, plasticizers, property modifiers, stabilizers, surfactants, fillers, colorants, pigments, antioxidants, antistatic agents, antifungals, bactericides, UV-blockers, UV-stabilizers, and lubricants). These additives pose a significant obstacle in the search for methods to degrade polymers.

[0005] Fine materials, such as carbon black and nanoparticles, are known to be used to remove contaminants from aqueous systems, such as wastewater. However, these small materials are generally not suitable for non-aqueous systems and are often incompatible with polymer degradation processes, for example, due to process interference, poor mixing characteristics, and non-dispersibility in commonly used solvents.

[0006] Previously published patent application WO 2014 / 209117 A1 discloses a reusable trapping complex comprising a catalyst, functionalized magnetic nanoparticles, and a bridging portion only between the catalyst body and the magnetic nanoparticles. This trapping complex can be used to degrade polymers into oligomers and / or monomers. The catalyst complex can also be used to remove additives from solvents used in the degradation process.

[0007] WO 2014 / 142661 A2 discloses functionalized magnetic particles or magnetic dispersions that are functionalized with suitable chemical groups for catalyst recovery, functionalized with active catalysts, functionalized with polyelectrolytes, functionalized with polymers, and functionalized with reactive chemical groups.

[0008] Therefore, it is still necessary to thoroughly remove contaminants, especially during polymer degradation, without interfering with the process itself.

[0009] The present invention provides an improved method for removing additives from polymer materials and an additive trap, for example, for degrading polymers, which overcomes at least one of the aforementioned disadvantages without compromising functionality and advantages. Summary of the Invention

[0010] The invention relates in a first aspect to the use of an improved, reusable capture complex according to claim 1 for the releasable capture of additives present in polymeric materials, and in a second aspect to the method according to claim 7, which exhibits several significant improvements over the prior art, for example, in terms of the use of very low amounts of the complex per quantity of additives (0.2-18 wt% to 17-80 wt% [weight catalyst / weight polymer]), insensitivity to contaminants (e.g., environmental substances), insensitivity to the composition of the feedstock (i.e., the type of polymeric material to be degraded and the type of additive), etc. In terms of quantity, the invention provides a capture agent that can be reused (more than 50 times, which is not present in prior art degradation methods), allowing for any mixture of waste polymers (unknown in the prior art, where prior art methods typically require very clean, well-separated materials of a single type / source), etc.

[0011] The trapping complex of the present invention comprises three distinguishable units: nanoparticles, bridging portions connected (e.g., via covalent bonds) to the nanoparticles, and a catalyst entity (chemically, e.g., via covalent bonds) connected to the bridging portions. The bridging portions exist only between the catalyst and the nanoparticles, and there is no "coating" or shell on the nanoparticles. The complexes of the present invention differ, for example, from complexes in which the bridging portions completely cover the nanoparticles (e.g., core-shell particles). The complexes may be ionic complexes.

[0012] The additives are typically present in small amounts, for example, in amounts <10,000 ppm (based on the total amount of polymer). The capturing complexes of the present invention are particularly suitable for capturing colored additives, especially dyes, pigments, inks, paints, and colored chemicals.

[0013] It should be noted that the trapping complexes are intended to perform various functions, such as catalyzing polymer degradation, trapping additives, etc. Considering the polymer degradation process, the complexes of the present invention are preferably poorly dispersed in water or aqueous solutions, as opposed to, for example, nanoparticles themselves.

[0014] The nanoparticles of this invention are magnetic. Accordingly, nanoparticles comprising magnetic materials, as well as particles that can be sufficiently magnetized under a relatively moderate magnetic field (e.g., as used in this method), are included. An advantage of using magnetic nanoparticles is that these magnetic nanoparticles can be recovered after use, for example, by magnetic attraction. Suitably, the magnetic nanoparticles contain oxides of iron, manganese, and / or cobalt. For example, but not exclusively, iron oxides in the form of Fe3O4 are preferred. Another suitable embodiment is CoFe2O4.

[0015] It has been found that nanoparticles should be small enough for the captured complex to act as a catalyst, thereby degrading the polymer of this method into smaller units, wherein the yield of these smaller units, specifically their monomers, is sufficiently high for commercial reasons. In this regard, it is noteworthy that the commercial value of the (waste) polymer to be degraded is relatively small, i.e., the degradation cost should also be low. It has also been found that nanoparticles should be large enough to enable the reuse of the complexes of this invention by recovering the captured complexes. Economically disadvantageous is that the captured complexes will be removed along with the waste or the obtained degradation products. Suitable nanoparticles have an average diameter of 2-500 nm. Nanoparticles containing iron oxides are preferred.

[0016] It should be noted that the nanoparticles of this invention are not considered as supports. Prior art supports typically involve larger entities, usually in the mm or larger range. It is noteworthy that catalysts on supports are considered unsuitable for the methods of this invention, particularly because the yields of degradation products are too low (or the same time and / or temperature required to achieve such yields is unsuitable). For example, Valkenberg et al., in “Immobilisation of ionic liquids on solid supports,” Green Chemistry, 2002(4), pp. 88-93, show ionic liquids attached to solid supports (e.g., metal oxides such as TiO2, SiO2, Al2O3, etc.). Valkenberg shows a comparison between unsupported and supported Fe-ILs in Table 3. For anisole, the conversion decreased from 90% to 6.5% (or about 30% for charcoal), and for m-xylene, from about 34% to 15% (or about 18% for charcoal). Further optimization of reaction conditions was found important. Therefore, supports are generally not considered for ionic liquids in terms of conversion.

[0017] The catalyst entity of the present invention comprises at least two parts. This has been found to contribute to at least some advantages of the invention. The first relates to an aromatic moiety having a positive charge (cation). The second relates to a moiety having a negative charge (anion), typically a salt complex. In the specification, the term "partially" referring to the catalyst entity means that a portion of the catalyst entity is charged, and therefore not typically all of the entity. The negative and positive charges are typically balanced. It has been found that, in terms of conversion and selectivity, particularly in terms of the degradation of polyesters and polyethers, the positively and negatively charged moiety have a synergistic and enhancing effect on the degradation process of the polymer.

[0018] The aromatic moiety preferably comprises a heterocycle having at least one, preferably at least two, nitrogen atoms. The aromatic moiety preferably has a stable positive charge. The heterocycle may have 5 or 6 atoms, preferably 5. Typically, the aromatic moiety carries a positive charge. If nitrogen is present, the charge is on nitrogen. Suitable aromatic heterocycles are pyridimines, imidazoles, piperidines, pyrrolidines, pyridines, pyrazoles, oxazoles, triazoles, thiazoles, methimazoles, benzotriazoles, isoquinols, and viologen-type compounds (having structures such as two coupled pyridine rings). Imidazole structures are particularly preferred, leading to imidazole-onium ions.

[0019] The negatively charged portion may involve a salt complex portion, preferably having a metal ion with two or three positive charges (e.g., Fe). 3+ Al 3+ Ca 2+and Cu 2+ ) and negatively charged counterions (e.g., halides, such as Cl-) - F - and Br - The metal salt complex portion of the compound. Alternatively, the negatively charged portion may be a negatively charged anion, such as a halide.

[0020] The catalyst entity and nanoparticles of the present invention are joined by bridging portions to attach the catalyst entity to the nanoparticles. The connection typically involves a physical or chemical bond between the bridging portion and the catalyst entity on one hand, and between the bridging portion and the nanoparticles on the other. Specifically, multiple bridging portions are connected to or bonded to the surface region of the nanoparticles of the present invention. It is important to note that maintaining the function of the catalyst complex is crucial. Not only is it important to provide suitable bridging portions (or combinations thereof), but it is also important to match several bridging portions to the surface area of ​​the magnetic nanoparticles of the present invention. In this respect, the size (diameter) of the nanoparticles of the present invention is also important.

[0021] It has been found that weak organic acids, silanols, silyl groups, and silanols attach well to nanoparticles. Therefore, more specifically, the bridging moiety comprises a functional group for bonding to the oxide of the nanoparticle and a second linking group attached to the catalyst entity. The functional group is, for example, a carboxylic acid, alcohol, silicic acid group, or a combination thereof. Other acids, such as organic sulfonic acids, are not excluded. The linking group includes, for example, a terminal olefin chain attached to an aromatic heterocyclic moiety, wherein the olefin chain is typically between C1 and C6, such as propylene and ethylene.

[0022] The bridging portion is suitably provided as a reactant, wherein the linking group is functionalized to chemically react with the catalyst entity. For example, the suitably functionalized linking group is provided as a substituted alkyl halide. Suitable reactants include, for example, 3-chloropropyltrialkoxysilane, 3-bromopropyltrialkoxysilane, 2-chloropropyltrialkoxysilane, and 2-bromopropyltrialkoxysilane. The alkoxy group is preferably ethoxy, although methoxy or propoxy are not excluded. Trialkoxysilanes are preferred, although dialkyldialkoxysilanes and trialkyl-monoalkoxysilanes are not excluded. In the latter case, the alkyl group is preferably a lower alkyl group, such as a C1-C4 alkyl group. Thus, as described above, at least one of the alkyl groups is functionalized, for example, with a halide.

[0023] The reactants are then reacted with a catalyst entity. Preferably, the reaction produces a positive charge on the aromatic moiety, and more particularly on the nitrogen atom of the aromatic moiety. The reaction is, for example, a reaction of a (substituted) alkyl halide with a nitrogen-containing aromatic moiety, forming a bond between the nitrogen atom and the alkyl group. The nitrogen then carries a positive charge, and the halide carries a negative charge. The negatively charged halide can then be enhanced by adding a Lewis acid to form a metal salt complex. An example is the conversion of chlorides to FeCl4. - .

[0024] In order to carry out the method of the present invention, the above-mentioned factors need to be considered in terms of conversion, selectivity, and economic feasibility. Otherwise, effective capture of the additives cannot be achieved, resulting in degradation. The bridging portion of the present invention provides the above-mentioned characteristics (in addition to the nanoparticles of the present invention). It is worth noting that, to date, no economically feasible method for polymer degradation has been provided.

[0025] In embodiments of the complex-capturing compound of the present invention, the bridging portion (and the catalyst entity bound thereto) is 5 × 10 -10 -0.1, preferably 1×10 -7 -0.01, more preferably 2×10 -5 -10 -3 For example, 4×10 -5 -10 -4 The amount (molar bridging portion / gram of magnetic particles) is provided. For example, with regard to effective capture, a relatively large amount is preferred, while a slightly smaller amount can be used in terms of the amount of catalyst and its cost, especially since magnetic nanoparticles are considered a relatively inexpensive component for capturing complexes. Surprisingly, the method of the present invention can be carried out with very low amounts of captured complexes compared to prior art methods.

[0026] In embodiments of the captured complex of the present invention, the average diameter of the nanoparticles is 2 nm-500 nm, preferably 3 nm-100 nm, more preferably 4 nm-50 nm, for example 5-10 nm. As mentioned above, the particles are preferably neither too large nor too small. It has been found, for example, that particles of a relatively small size of 5-10 nm are optimal for the use and recycling of the captured complex. It is worth noting that the term "size" refers to the average diameter of the particles, where the actual diameter of the particles can vary slightly due to their characteristics. Furthermore, the size is determined by each individual particle. For the average value, a numberweight average can be used. In approximations, the average value can be the size of the particles with the largest number or an intermediate size.

[0027] In an alternative embodiment, the nanoparticles may have a size in the range of 50-200 nm, for example 80-150 nm, such as 100 nm. In this embodiment, the nanoparticles exist in the form of aggregates, which may be formed, for example, in solution. These aggregates typically have a size in the range of 50-200 nm, for example 80-150 nm, such as 100 nm. The particle size and its distribution can be measured, for example, by light scattering, using a Malvern dynamic light scattering device, such as the NS500 series. In a more laborious approach, typically used for smaller particle sizes and equally applicable to larger sizes, representative EM images are acquired, and the size of individual particles is measured on the images.

[0028] In the case of degradation, a solid polymer is provided in a suitable solvent. Therefore, this method can be considered a solid-liquid degradation process supported by the addition of a recyclable trapping complex. Alcohols can be used, for example. Preferred alcohols are aliphatic, such as alkanols and alkyldiols. Mixtures of alcohols and / or mixtures of water and alcohols are also considered feasible. For the claimed glycolysis, the solvent is a monool or diol, such as an alkanol or alkyldiol. Therefore, this solvent is also used as a reactant in polymer degradation.

[0029] This method can be performed intermittently, continuously, semi-continuously, or in combination.

[0030] Details of the degradation method can be found in the international applications PCT / NL2014 / 050418 and WO2014 / 142661 A2 filed by the same applicant, which are incorporated herein by reference.

[0031] Suitablely, the polymer to be degraded is a condensation polymer, including polyesters, polyethers, polyimides, and polyamides. Representative examples include PET (polyethylene terephthalate), PEF (polyethylene furanate), PTT (polypropylene terephthalate), and PLA (polylactic acid).

[0032] The advantage of this method is its relative insensitivity to contaminants, such as additives like pigments, fillers, and filter agents, which are separated during the degradation process. The inventors understand that additives adhere to the captured complex. In particular, the bridging portions and catalyst entities co-adhered to the nanoparticles appear capable of adsorbing hydrophobic colorants. After the degradation process, the captured complex can be regenerated as the additives are removed by washing. Preliminary studies have shown that several (5-20) batches of degradation treatment can be performed on the polyester bottles before a washing step is required. Therefore, the method of this invention is considered robust even under relatively suboptimal conditions (e.g., in a factory setting).

[0033] Compared to existing methods, the method of the present invention is characterized by the fact that the captured complex can be recovered. It is preferred to use the captured complex of the present invention in the method of the present invention. In one embodiment, recovery includes providing a second solvent, for example, that acts as a detergent, and separating the captured complex from any additives and / or the first solvent, for example, using an electromagnetic field. This separation and recovery is particularly necessary to separate the additives from the captured complex. Thus, the captured complex can be reused. In another embodiment, the captured complex is reused in this process without recovery. More precisely, recovery occurs only after multiple degradation stages.

[0034] Therefore, the present invention provides a solution to at least one of the above-mentioned problems. Various embodiments and implementations of the present invention can be combined.

[0035] The advantages of this instruction are explained in detail. Detailed Implementation

[0036] The present invention relates, in a first aspect, to the capture complex according to claim 1 and its use therein.

[0037] In embodiments of the captured complex of the present invention, the nanoparticles are at least one of ferromagnetic particles, antiferromagnetic particles, ferrimagnetic particles, synthetic magnetic particles, paramagnetic particles, and superparamagnetic particles, for example, particles containing at least one of Fe, Co, Ni, Gd, Dy, Mn, Nd, and Sm, and preferably particles containing at least one of O, B, C, and N, such as iron oxides, like ferrites, such as magnetite, hematite, and maghematite. Magnetite and maghematite are preferred magnetic particles in terms of capturing capacity. Considering cost, relatively inexpensive particles, such as particles containing Fe, are preferred even when the captured complex of the present invention is fully or largely recovered. Furthermore, non-magnetic nanoparticles can be used, typically particles containing oxides (e.g., Al2O3, CaO, and clays, such as TOT clay and TO clay). Preferably, the nanoparticles are selected to be substantially insoluble in (alcohol) solvents and also insoluble at higher temperatures above 100°C. One oxide that tends to dissolve in alcohols (such as ethylene glycol) at higher temperatures is, for example, (amorphous) SiO2. It is worth noting that some fine workmanship may be required.

[0038] In embodiments of the capture complexes of the present invention, the bridging portion comprises functional groups for adhesion or binding to nanoparticles and linking groups connected to heteroatoms of the catalyst entity, particularly the aromatic portion. Suitable functional groups are, for example, weak organic acids (e.g., carboxylic acids or dicarboxylic acids) and silanols (including silanediols and silanetriols). Linking groups are, for example, alkyl groups such as ethyl, propyl, butyl, pentyl, and hexyl. When forming the complexes of the present invention, the bridging portion can be introduced as a reactant in the form of a silyl group (e.g., silyl ethers, such as triethoxysilylpropyl halides (e.g., triethoxysilylpropyl-3-chloride)). For weak organic acids, Ka is typically in the range of 1.8 × 10⁻⁶. -16 The value varies between 55.5 and 55.5. It has been found that even with negative expectations, these bridging groups do not lead to unacceptable performance degradation of the catalyst entity, such as reduced catalytic performance.

[0039] In embodiments of the capture complex of the present invention, the aromatic portion has at least one tail. This tail refers to a tail-like portion. The at least one tail preferably has a C1-C6 length, such as C2-C4, and the at least one tail is attached to at least one nitrogen atom. It has been found that a slightly longer tail can yield slightly higher yields for optimal polymer degradation. Regarding the quality of the captured complex provided, a slightly shorter tail has been found, and for the capturing additive, an excessively long tail limits capture.

[0040] In embodiments of the captured complex of the present invention, the magnetic nanoparticles comprise (each particle) at least one bridging portion and a catalyst entity, preferably 2-10. 4 Each bridging portion and catalyst entity (BC per particle), more preferably 10-10 3 Each bridging component and catalyst entity (BC per particle) is used. In principle, as many catalyst entities as possible can be provided. However, the amount of catalyst entities and their function are slightly less than the achievable amount. Furthermore, when larger particles are chosen, a certain amount of more catalyst entities can be present.

[0041] In embodiments of the captured complex of the present invention, the amount of the bridging portion and the catalyst (entity) attached thereto is 0.03-99 wt%, preferably 0.1-75 wt%, more preferably 0.2-25 wt%, and even more preferably 0.3-10 wt%, relative to the total weight of the captured complex. Also as mentioned above, under other boundary conditions (e.g., applied temperature), a relatively low amount of catalyst entity of 0.1-5 wt%, for example 0.6-3 wt%, is found to be optimal. The amount of catalyst and / or bridging portion can be determined by TGA. It should be noted that the catalyst and bridging portion of the present invention can form a single (mono) layer or a portion of a monolayer that does not completely cover the nanoparticles. The captured complex of the present invention can be washed before application in the method of the present invention. The above weight percentages are relative to the total weight of the (dry) captured complex.

[0042] In a second aspect, the present invention relates to the method according to claim 7. In this method, an additive is provided that is typically released from the polymer during polymer degradation. It has been found that the method and the capturing complex of the present invention are also applicable to methods for degrading natural polymers. The additive is preferably captured under conditions where an excess (in terms of capturing capacity) of the capturing complex is added. The excess is determined on a molar basis. The additive is typically hydrophobic.

[0043] In embodiments of the method of the present invention, the additive and the complex are present in a hydrophilic solution (e.g., ethylene glycol and water). The method may further include the steps of precipitating the complex and the additive, for example by lowering the temperature; removing the hydrophilic solution, for example by decantation; adding a detergent (e.g., CH2Cl2); dissolving the additive in the detergent; and recovering the complex. Alternatively, the complex can be captured by filtration. Using this relatively simple method, most or almost all additives can be captured and released from the captured complex.

[0044] In embodiments involving pigments in depolymerized PET (monomer / BHET), for example by... 1 ¹H NMR showed no residual pigment was detected.

[0045] In one embodiment, when a detergent (i.e., an organic solvent, preferably a hydrophobic solvent) is added, the method of the present invention further includes the step of adding a hydrophilic solution. This establishes a two-phase system. Therefore, the hydrophobic additive is separated from, for example, the reaction product.

[0046] In embodiments of the method of the present invention, the polymer provides additives upon degradation, wherein the polymer is a mixture of waste polymers, which optionally contains at least one coloring polymer. Using the method of the present invention, most additives, particularly colorants, can be captured. The capture process is highly efficient because no residual additives can be detected, for example, visually; for example, a completely transparent (uncolored) solution or monomer / dimer product is obtained. Specific wavelengths absorbed by UV-Vis are largely lost.

[0047] Therefore, the method of the present invention can process waste polymers, and even mixtures of polymers with different properties (e.g., different colors). It has been found that degradation yield and capture efficiency are not significantly affected. In a further step, an active compound, such as carbon black, can be added to capture and remove residual additives.

[0048] It should be noted that existing technological methods can only process relatively pure waste polymers at best, and even then, the results are disappointing.

[0049] In embodiments of the method of the present invention, the polymer may be selected from natural polymers, bio-based polymers, biodegradable polymers, polymers formed directly or indirectly from fossil fuels, and combinations thereof. The polymer is polyester, polyether (such as polyoxymethylene (POM)), polyamide, polyamine, condensation polymer, preferably polyester, such as polycarboxylate, wherein the polycarboxylate is preferably selected from at least one or more of polyethylene terephthalate (PET), polyethylene furanate (PEF), polybutylene terephthalate (PBT), polypropylene terephthalate (PTT), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyethylene adipate (PEA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene naphthalate (PEN), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and condensation polymers of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid (VECTRAN). In other words, a wide variety of polymers that are claimed to be protected can be degraded by the method of the present invention. For example, some adjustments may be necessary regarding the catalyst used, the temperature employed, and the solvent used. The method of the present invention is best suited for degradation using hydrolysis or glycolysis, for example, the degradation of polyesters and polyethers, particularly PET and PEF.

[0050] After degradation, the resulting mixture is cooled to a temperature of 50-85°C. At this temperature, magnetic separation can be performed. Similarly, optional separation techniques such as filtration and centrifugation can be used. The mixture can then be further cooled, for example, to 1-10°C, to precipitate, for example, monomers or dimers. The resulting precipitate can be further dried, for example, at 50-75°C.

[0051] In embodiments of the method of the present invention, the amount of catalyst complex relative to the total weight of the provided polymer is 0.1-35 wt%, preferably 0.5-20 wt%, more preferably 1-10 wt%, and even more preferably 2-7 wt%, for example (wt / wt) 1ABC:15PET(:45EG, ethylene glycol). A higher amount of catalyst results in a shorter reaction time, while a lower amount results in a longer reaction time. The amount of catalyst can be varied depending on other boundary conditions.

[0052] In embodiments of the method of the present invention, the additives have an average size of 1-100 nm and a molecular weight of 10-5000 Daltons. Specifically, the following additives can be captured: organic pigments (e.g., acridine dyes, anthraquinone dyes, arylmethane dyes, diarylmethane dyes, triarylmethane dyes, azo dyes, diazo dyes, nitro dyes, nitroso dyes, phthalocyanine dyes, quinone imine dyes, azin dyes, eurhodin dyes, safranin dyes, indamin, indophenol dyes, oxazine dyes, oxazone dyes). Pigments include: thiazide dyes, thiazolium dyes, xanthan dyes, fluorene dyes, quinine dyes, fluorescent ketone dyes, rhodamine dyes and their derivatives; bio-pigments (e.g., alizarin, deep alizarin, gamboge, carmine, alizarin rose, indigo, Indian yellow and Tyrolean purple); non-bio-organic pigments (e.g., quinacridone, magenta, phthalocyanine green, phthalocyanine blue, pigment red 170, benzidine yellow); metallic pigments (e.g., cadmium pigments, chromium pigments, cobalt pigments, copper pigments, iron oxide pigments, lead pigments, manganese pigments, mercury pigments, titanium pigments and zinc pigments); and other inorganic pigments (e.g., carbon pigments, clay inorganic pigments and ultramarine pigments and their salts) and combinations thereof. Depending on, for example, the properties of the pigment, the capture efficiency can vary from 25% to >99.99%. Furthermore, released additives can also be captured by other compounds (e.g., carbon black).

[0053] One embodiment of the method of the present invention further includes a step of recovering the catalyst attached to the magnetic particles using an electromagnetic field gradient in a magnetic field preferably from 0.1 to 5 T, preferably from 0.3 to 2 T, more preferably from 0.5 to 1.5 T, for example from 0.8 to 1.3 T, for example 1 T. This is because such a relatively small magnetic field has been found sufficient to recover the captured complex of the present invention. This is advantageous, for example, in terms of reactor design. In one embodiment, water is provided to separate the complex of the present invention from the present solvent. It has been found that removing the complex of the present invention from the aqueous phase is much easier than removing it from the present solvent phase. By providing a suitable captured complex, such as the complex of the present invention, the catalyst (complex) can be recovered. It has been found that typically 95% of the captured complex can be recovered, and typically even 98-99%. Therefore, the captured complex of the present invention can be reused 20-100 times, thus saving costs, for example. It has been found that the recovered captured complex functions just as well as the fresh (unused) complex.

[0054] One embodiment of the method of the present invention further includes a step of cyclically capturing the complex. After recovery, the complex of the present invention can be recycled or removed and, for example, stored for later use.

[0055] In one embodiment of the method of the present invention, the polymer is polyethylene terephthalate (PET) or PEF, the solvent is ethylene glycol, and the catalyst includes butylimidazole or butylmethylimidazole and FeCl4. - The bridging portion is triethoxysilylpropyl or trihydroxysilylpropyl, and the nanoparticles are magnetite and / or maghemite. The nanoparticles preferably have a size of 5-10 nm. The bridging portion preferably has a size of 10 nm. -4 -10 -2 Molar bridging fraction per gram of nanoparticles, for example, 2 × 10⁻⁶. -4 -10 -3 The amount of molar bridging portions per gram of nanoparticles is present. Assuming that a predetermined amount (moles) of bridging portions is connected to a predetermined amount (grams), then virtually all bridging portions are connected to the nanoparticles and remain substantially connected during the method of the present invention. Given the large amount of available waste PET, exceeding hundreds of thousands of tons annually, this is a particularly preferred embodiment.

[0056] The captured complex of the present invention can be used, for example, in a complex-to-PET ratio (weight / weight) ranging from 1:5 to 1:500, such as 1:10 to 1:15. Additionally, the amount of ethylene glycol to PET can vary from 1:2 to 1:20, such as 1:3 to 1:5. The waste polymer can involve a single type of polymer, such as PET, PEF, PA, etc., or a mixture thereof. It typically contains 50-99.9% by weight of a specific polymer, such as PET, with the remainder being impurities, other polymers, other compounds, etc.

[0057] The present invention will be further described in detail with reference to the accompanying drawings and embodiments, which are exemplary and illustrative in nature and do not limit the scope of the invention. It will be apparent to those skilled in the art that various modifications, whether obvious or not, may be considered to fall within the scope of protection defined by the claims of this invention. Attached Figure Description

[0058] Overview of the attached figures

[0059] Figures 1a-e illustrate the chemical reactions and the trapping complexes.

[0060] Detailed description of the attached figures

[0061] Figure 1a illustrates the chemical reaction in which poly(ethylene terephthalate) is degraded in 1,2-ethylene glycol. Similar results were obtained using the capture complex of the present invention; in one embodiment, bim was used as the aromatic catalyst entity. The result is the formation of bis(2-hydroxyethyl) terephthalate (BHET). Furthermore, it is shown that BHET can be converted into dimers and oligomers (typically having 3-12 monomers).

[0062] Figure 1b A schematic diagram of the complex of the present invention is shown. A represents nanoparticles, such as magnetite; B is a bridging portion directly connected to the nanoparticles, such as trisilanolpropyl; C is a catalyst entity directly connected to the bridging portion, wherein C1 is the positive catalyst portion, such as bim, and C2 is the negative catalyst portion, such as Cl. - If present (and therefore not shown), the tail will extend away from the nanoparticle.

[0063] Figure 1c Nanoparticle A is shown, which is surrounded by a number of bridging portions and catalyst entities attached to the nanoparticle.

[0064] Figure 1dAn example of preparing a capture complex according to one embodiment of the present invention is shown. In a first step, 3-chloropropyltriethoxysilane is reacted with 1-butylimidazole overnight under heating to form a BC subcomplex; here, the butyl group forms the tail. The temperature is from 320 to 360°K, and the reaction time is from 30 to 360 minutes, depending on the temperature. The reaction produces almost 100% BC subcomplex. The BC subcomplex is then grafted onto nanoparticles containing iron oxide. In this embodiment, it is understood that the grafting leads to linkage due to the presence of the carboxylic acid group. Alternatively, in the presence of the silanol group, the grafting can be in the form of chemical bonding.

[0065] Figure 1d and 1e The reaction equation for forming the captured complex of the present invention according to a preferred embodiment is shown. In the first step ( Figure 1d In this process, 3-chloropropyltriethoxysilane reacts with 1-butylimidazole overnight under heating to form a BC subcomplex; here, the butyl group can be referred to as the tail. Temperatures range from 320 to 470 K, and reaction times vary from 30 min to overnight, depending on the temperature. This reaction produces almost 100% BC subcomplex. The resulting intermediate is a combination of a positively charged N-[3-(triethoxysilyl)propyl]-butylimidazole and a negatively charged chloride. Subsequently, a Lewis acid, such as FeCl3, can be added. However, this is not considered necessary. In the second step, as... Figure 1e As shown, the ethoxy groups of the reaction product are converted into hydroxy groups to form silanol groups. In the third step, which is carried out, for example, in water or ethanol or an aqueous solution of ethanol, preferably in the presence of an acid, the silanol reacts with the surface of the nanoparticles. The resulting captured complex can then be (re)dispersed in a solvent required for polymer degradation, such as a diol.

[0066] Example

[0067] Colored PET was tested, and colorless PET was tested beforehand. The results were on the same order of magnitude in terms of both conversion and selectivity for BHET. Therefore, the inventors conclude that coloring additives have little or no effect in this respect. Furthermore, additives (e.g., pigments) can be readily removed from the degradation products.

[0068] Similar tests, as described above, have been conducted on a wide range of virgin (PET) materials, such as polyester clothing, PET carpets, PET materials used in the automotive industry, recycled PET, and multilayer PET trays containing other polymers (such as PE and PP). The results are on the same order of magnitude. Therefore, the inventors conclude that the process is highly insensitive to different virgin (PET) materials and is also robust.

[0069] In one embodiment, the inventors used 1g of Figure 1e The captured complex and 5g of PET were used. Experiments showed that all colorants were removed by the complex, i.e., no color could be detected in the obtained BHET / ethylene glycol (EG) / aqueous phase.

[0070] It has been found that the complex of the present invention is capable of removing at least 2.5 mg of colorant / g complex in a single use; examples show removal of 25 mg of colorant / g complex in a single run. When used consecutively, for example, five times, the complex has been found to remove at least 12.5 mg of colorant / g complex. When used multiple times (e.g., up to 50 times), no decrease in efficiency was found; therefore, it is considered that the complex is capable of removing at least 125 mg / g complex. This capability is considered sufficient for most applications considered.

[0071] In a preferred embodiment, the washing step is performed to remove the captured compounds. Advantageously, this washing only needs to be performed after a series of runs or cycles. If the amount of additive is large relative to the amount of captured complex, the captured complex can be washed; as mentioned above, the complex typically has a relatively large ability to capture the additive, and the complex only needs to be washed after 5-10 cycles.

[0072] Other embodiments

[0073] Examples of biodegradable polymer construction:

[0074] Polyesters: PET, PEF, PTT, PLA, polycarbonate

[0075] Polyethers: Cellulose

[0076] Polyamides: Nylon 6

[0077] The ionic liquid being tested:

[0078] Imidazolium-functionalized acids, piperidinium-functionalized acids, pyridinium-functionalized acids, pyrrolidine-functionalized acids, sulfonium-functionalized acids with an additional side group R3, ammonium-functionalized acids with additional side groups R3 and R4, and phosphonium-functionalized acids with additional side groups R3 and R4; all of which have at least side groups R1 and R2 and a counterion X. - X can be selected from F, Cl, Br, I, dicyandiamide, bis(trifluoromethylsulfonyl)imide, preferably Cl.

[0079] Functional group R1 can be a (mono or poly, 1-4) carboxylic acid, while functional group R2 can be an alkane, typically a straight-chain or branched alkane. Functional groups R3 and R4 can be selected from H, CH3, and R1 and R2. Functional groups R1-R4 are chosen independently and can be (partially) the same or different. Side group R2 can have m or o carbon atoms and can be branched, while side group R1 having n (typically 4-20) carbon atoms is preferably unbranched.

[0080] Therefore, in summary, aromatic and non-aromatic moieties, typically containing heteroatoms (N, S, O, P) with a positive charge on (or one of) the heteroatoms, have been tested, and various side groups have been tested. The most promising have been claimed, namely aromatic compounds containing nitrogen atoms.

[0081] Metal salts:

[0082] Various metal salts containing metal ions with two or three positive charges and counterions with negative charges have been tested, especially Fe, Ca, Co, Mn and the aforementioned counterions.

[0083] Bridge connection section:

[0084] For the bridging component, weak acids and functionalized acids, such as carboxylic acids and oxysilanes, such as methoxysilanes or ethoxysilanes, have been tested.

[0085] Nanoparticles:

[0086] Various nanoparticles have been tested, including those with O as a counterion, Fe, Co, and Mn as metal ions, and some combinations thereof. All of these have demonstrated excellent functionality.

[0087] The size is typically relatively small, so nanoparticles have a lower limit of 2 nm and an upper limit of 500 nm. Both have some minor advantages and disadvantages.

[0088] Catalyst recovery:

[0089] Most or all of the catalyst can be easily recovered, depending on the recovery method. After 30 cycles, magnetic recovery yielded over 98% of the initial amount, so there was virtually no loss. If filtration is used, even higher amounts can be recovered.

[0090] Example 2: Depolymerization Method

[0091] The reference standard for laboratory experiments is 50g of ethylene glycol (EG) in a 100mL flask. The reference mass ratio for the reaction is 1g of dry catalyst complex particles : 5g of PET : 50g of EG. The reference trapping complex includes 5nm magnetite nanoparticles, trisilyl propyl as a bridging moiety, and (bim)FeCl4 or (bmim)FeCl4 as an ionic liquid. The reference reaction is carried out as follows:

[0092] The catalyst complex dispersion was homogenized by manual shaking for 5 minutes. 41g of EG was added to 10g of the captured complex dispersion, and the liquid was briefly mixed by hand to homogenize the dispersion. Then 5g of PET flakes was added, and the round-bottom flask was placed in a heating device. The PET flakes were obtained from... It is prepared from commercially available colored PET bottles, for example (the blue in the blue PET bottle) and (Red in the red PET bottle). Heating was initiated, and after 20 minutes, the reaction mixture reached a reaction temperature of 150-200°C. The reaction was tracked in real time by measuring the concentration of BHET as a function of time using control samples during the process. The concentration of BHET was determined by HPLC. The results are listed in Table 1. It was found that the reaction conditions (temperature, concentration of the trapped complex, type and size of nanoparticles) could be varied over a sufficiently wide range.

[0093] Table 1: PET to BHET conversion as a function of time, serving as a reference for PET depolymerization.

[0094]

[0095] Example 3

[0096] Following the depolymerization reaction, water is added in a 1:1 ratio, and the captured complex is separated from the monomer-containing liquid stream by magnetic separation. The liquid phase is decanted, leaving a slurry layer of the captured complex at the bottom of the beaker. The captured complex can be readily redispersed in ethylene glycol. To release the colorant from the captured complex, an organic solvent is added; in this example, CH2Cl2 is added and the mixture is stirred vigorously. The captured complex is magnetically precipitated, leaving a clear red or blue supernatant, depending on the type of bottle used for the flakes. The supernatant can be decanted, and the captured complex can be redispersed in ethylene glycol.

[0097] Example 4

[0098] Examples 2 and 3 were repeated using a white PET bottle containing a white pigment (apparently TiO2). However, when magnetic sedimentation was performed in the presence of an organic solvent to release the pigment, the liquid phase remained along with the precipitated trapped complex. After being left to stand overnight, a layer of white pigment particles settled overnight on top of the trapped complex precipitate.

[0099] Example 5: Preparation of catalyst-captured complexes

[0100] Preparation of linker-catalyst complexes (bridge-catalysts)

[0101] Alkyl imidazole and halosilane were mixed at a molar ratio of 1:1 and stirred at a slightly higher temperature for 8 hours.

[0102] Preparation of catalyst complexes

[0103] Nanoparticles were prepared based on the method first described by Massart et al. in 1981:

[0104] Fe(II) solution and Fe(III) solution were mixed at a molar ratio of 1:2. Iron oxide nanoparticles were formed by co-precipitation in an alkaline medium under stirring. Subsequently, the resulting iron oxide particles were washed with water and ethanol.

[0105] Next, a sufficient amount of the linker-catalyst complex diluted with ethanol was thoroughly mixed with the dispersion of iron oxide particles, and then ammonia was added. The reaction mixture was stirred for 15 hours. The amount of linker-catalyst per nanoparticle can be varied depending on the ratio between the linker-catalyst and the nanoparticles.

[0106] The particles were washed with acetone before being redispersed in ethylene glycol.

[0107] Although described in detail in an illustrative context, the invention can be best understood in conjunction with the accompanying embodiments and drawings.

[0108] It should be understood that for commercial applications, using at least one variant of the system of the present invention is preferred, as it is similar to those disclosed in this application and is within the spirit and scope of the invention.

Claims

1. A method for capturing an additive that can be released from a polymeric material, wherein the polymeric material is one or more of polyester, polyamide, polyamine, condensate, and polyether, the method comprising providing the additive, and capturing the additive in the presence of a capturing complex, wherein the polymeric material releases the additive upon degradation, and wherein the polymeric material is a mixture of waste polymers, the method comprising the steps of: - Provides improved, reusable capture complexes; - Provides a mixture of waste polymer in solid form in a solvent, wherein the solvent is a monohydric alcohol or a dihydric alcohol; - The polymer material is degraded by glycolysis, wherein the solvent is used as a reactant, and wherein the captured complex catalyzes the degradation of the polymer material, wherein the additive is released from the polymer material, and wherein a mixture is obtained; - Use the capturing complex to capture the additive; - Separation is performed to separate the captured complex and the captured additive from the mixture; The captured complex is non-dispersible in water and comprises a catalyst entity, magnetic nanoparticles, and a bridging portion only between the catalyst entity and the magnetic nanoparticles, wherein the catalyst entity is connected to the bridging portion, and wherein the bridging portion is connected to the magnetic nanoparticles. The catalyst entity comprises an aromatic heterocyclic moiety having at least one nitrogen atom and a positive charge, and a negatively charged moiety, wherein the negative charge is on a metal salt complex moiety having two or three positively charged metal ions or negatively charged counterions. The magnetic nanoparticles described herein have an average diameter of 2 nm to 500 nm, and The bridging portion is 5×10 -10 Up to 0.1 moles of bridging portion per gram of magnetic nanoparticles are present.

2. The method of claim 1, wherein water is provided to the obtained mixture to separate the captured complex from the solvent.

3. The method according to claim 1 or 2, wherein an active compound is added to capture and remove residual additives.

4. The method according to claim 1 or 2, wherein the captured additive is hydrophobic.

5. The method according to claim 1 or 2, wherein the captured complex is regenerated by washing to remove the additive.

6. The method according to claim 1 or 2, wherein the polymer material is polyester.

7. The method according to claim 1 or 2, wherein the bridging portion is one or more of a weak organic acid, a silyl group, and a silanol.

8. The method according to claim 1 or 2, wherein the magnetic nanoparticles are at least one of ferromagnetic particles, antiferromagnetic particles, ferrimagnetic particles, synthetic magnetic particles, paramagnetic particles, and superparamagnetic particles.

9. The method of claim 8, wherein the magnetic nanoparticles comprise iron oxide.

10. The method according to claim 1 or 2, wherein the polymer material is polyethylene terephthalate or polyethylene furanate, the solvent is ethylene glycol, and the catalyst entity comprises imidazolium and FeCl4. - or Cl - The bridging portion is triethoxysilylpropyl or trihydroxysilylpropyl, and the magnetic nanoparticles are at least one of magnetite, hematite, and maghematite.

11. The method of claim 10, wherein the catalyst entity comprises butylimidazolium.

12. The method according to claim 1 or 2, wherein at least one additive is an organic pigment or a metal-based pigment.

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