Hydrogenated modified styrene resin

Abstract

A method for hydrogenating an aromatic-containing polymer is described. The method involves contacting a polymer solution containing an aromatic-containing polymer, a nonpolar solvent, and a polar solvent, wherein the polar solvent has a dielectric constant exceeding 7.6 at 25 °C and the nonpolar solvent has a dielectric constant of 5 or less at 25 °C, with a hydrogenation catalyst to hydrogenate the polymer, producing a polymer composition containing at least one hydrogenated aromatic ring and / or at least one partially hydrogenated aromatic ring. The volume ratio of the polar solvent to the nonpolar solvent is in the range of 10:90 to 80:20.

Description

Detailed Description of the Invention

[0001] [Cross - Reference to Related Applications] None.

[0002] [Background Art] A. Field of the Invention The present invention generally relates to a method for hydrogenating aromatic - containing polymers using a solvent system comprising a mixture of a non - polar solvent and a polar solvent. The polar solvent has a dielectric constant exceeding 7.6 at 25°C.

[0003] B. Description of Related Art By hydrogenating aromatic - containing polymers to saturated products, physical properties such as thermal and mechanical properties, and oxidation stability can be improved. Homogeneous catalysts and heterogeneous catalysts can be used in this hydrogenation process. Compared with homogeneous catalysts, heterogeneous catalysts have the advantage of being separable from the polymer solution. The heterogeneous - catalyst - based hydrogenation of aromatic - containing polymers (e.g., polystyrene) can be carried out in the liquid phase using a heterogeneous (solid) platinum (Pt) catalyst supported on a carrier such as an oxide, carbonate, or sulfate (e.g., Al 2 O 3 , SiO 2 , TiO 2 , CaCO 3 , BaSO 4 etc.). This catalyst can be dispersed in a hydrocarbon solvent such as cyclohexane or decahydronaphthalene (decalin). However, the heterogeneous - catalyst process has a problem of low reaction rate due to the limitation of mass transfer caused by the steric hindrance of bulky and long polymer chains. As a result, it becomes difficult for polymer molecules to approach the catalytic active sites.

[0004] To avoid mass transfer limitations, bimetallic catalysts dispersed in various solvents have been described. For example, Chinese Patent Application Publication No. 109482170 describes hydrogenating polystyrene by dispersing a supported bimetallic catalyst in a solution of tetrahydrofuran and hexamethylene. However, this process has the problem that the catalyst needs to use a templated support material, which can increase the cost and / or complexity of production. European Patent No. 1042374 by Wege et al. describes the use of polar solvents such as ethers having no α-hydrogen atoms adjacent to ether functional groups (e.g., methyl-t-butyl ether) as solvents suitable for hydrogenation reactions in the presence of nickel catalysts. However, this process has a problem with catalyst life. U.S. Patent No. 3,607,989 by Sonnabend describes obtaining hydrogenated polystyrene insoluble in 1,2-dichloromethane by hydrogenating polystyrene in an equal amount of 1,2-dichloromethane.

[0005] Heterogeneous catalyst processes are known, but the challenges of shortening reaction times and enhancing cost-effectiveness remain.

[0006] 〔Summary of the Invention〕 A discovery has been made that provides a solution to at least one of the problems associated with the hydrogenation of aromatic-containing polymers using a heterogeneous catalyst system. In one aspect, the solution involves the use of a solvent system (e.g., a mixture of solvents) comprising a polar solvent and a non-polar solvent. The polar solvent has a dielectric constant greater than 7.6 at 25 °C and is any solvent that is stable under hydrogenation conditions. The non-polar solvent has a dielectric constant less than 5 at 25 °C and is a solvent that is stable under hydrogenation conditions. The ratio of the polar solvent to the non-polar solvent ranges from 10:90 to 80:20. The advantage of using this type of solvent system is that, while maintaining the solubility of the hydrogenation product, the hydrogenation reaction rate can be improved by about 2 times compared to a similar reaction using only the non-polar solvent. The faster reaction rate can provide advantages such as shortening the batch time for producing hydrogenated or partially hydrogenated aromatic-containing polymers and simultaneously improving the production rate. Notably, the obtained hydrogenation product (e.g., PVCH) can be solubilized in the solvent system after cooling to ambient temperature, so there is no need to heat it for transporting the product solution for downstream processing, thus providing a more energy-efficient process. For example, in the piping connecting the hydrogenation reactor and the polymer isolation device (such as a flash chamber and a devolatilization extruder), even if the solution of the polymer product comes into contact with or is exposed to low-temperature conditions (e.g., a "cold spot"), the polymer product remains solubilized, so the piping will not be clogged by the precipitated polymer. Furthermore, the use of a volatile polar solvent facilitates solvent removal in downstream processes. These advantages can bring economic benefits in the production of hydrogenated or partially hydrogenated polymers (e.g., from polystyrene-based polymers to poly(vinylcyclohexane) (PVCH)). Additionally, with regard to PVCH, the obtained PVCH can be a fully aliphatic amorphous polymer having high heat resistance (T g = 145 °C), high heat-oxidation resistance, high resistance to polar chemicals, and / or high resistance to ultraviolet and gamma rays.

[0007] A method for hydrogenating an aromatic-containing polymer is described. This method involves reacting an aromatic-containing polymer solution with a hydrogenation catalyst under conditions sufficient to produce a polymer composition (e.g., PVCH) containing at least one hydrogenated aromatic ring and / or at least one partially hydrogenated aromatic ring, in the presence of hydrogen (H 2)It includes contacting in the presence of a gas. The aromatic-containing polymer solution includes an aromatic-containing polymer, a polar solvent having a dielectric constant exceeding 7.6 at 25 °C, and a nonpolar solvent. In a preferred embodiment, the aromatic-containing polymer is a polystyrene resin, and the hydrogenated or partially hydrogenated polymer includes poly(vinylcyclohexane). Non-limiting examples of the nonpolar solvent include cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, cycloheptane, dodecane, isopentane, decahydronaphthalene, or mixtures thereof. The polar solvent has a dielectric constant of 7.6 to 11 at 25 °C (for example, at 25 °C, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, and 11). In a preferred embodiment, the polar solvent has a dielectric constant of 9 at 25 °C. Non-limiting examples of the polar solvent include dichloromethane, 1,2-dichloroethane, or mixtures thereof. In a preferred embodiment, the nonpolar solvent is cyclohexane and the polar solvent is dichloromethane. The volume ratio of the polar solvent to the nonpolar solvent is 10:90 to 80:20, preferably 30:70 to 70:30. In some embodiments, it has been found that the yield decreases due to the inclusion of an excessive amount of the polar solvent (for example, more than 30% by volume). For example, using more than 30% by volume may not result in a further significant increase in the hydrogenation rate. In some embodiments, the hydrogenation reaction rate is greater than 1-fold, preferably 2-fold, more preferably 2.5-fold, and even more preferably 5-fold increased compared to the hydrogenation reaction rate under the same reaction conditions without using the polar solvent. The contacting conditions include a temperature of 100 °C to 220 °C, a pressure of 3.4 MPa to 7 MPa, or combinations thereof. Under these conditions, the aromatic-containing polymer is completely solubilized or at least partially solubilized in the solvent. The concentration of the polymer in the polymer solution is 5% to 20% by weight, preferably 8% by weight.By hydrogenating the aromatic-containing polymer, a hydrogenated or partially hydrogenated polymer composition can be obtained, and this polymer composition can be free of or substantially free of polymer scission compositions. In some embodiments, the hydrogenation catalyst comprises platinum (Pt), palladium (Pd), ruthenium (Ru), or any combination thereof, or an alloy thereof. The hydrogenation catalyst can comprise a support (e.g., silica (SiO. 2 ), alumina (Al 2 O 3 ), or titania (TiO 2 ), or any combination thereof). Since the process of hydrogenation can disperse or suspend the catalyst in a solvent, it can be a heterogeneous catalytic hydrogenation process.

[0008] Other embodiments of the present invention are described throughout this application. Embodiments described with respect to one aspect of the present invention are applicable to other aspects of the present invention, and vice versa. Each embodiment described herein is understood to be an embodiment of the present invention applicable to other aspects of the present invention. Any embodiment or aspect described herein can be combined with other embodiments or aspects described herein, and / or can be practiced with respect to any method or composition of the present invention, and vice versa is contemplated. Furthermore, the compositions of the present invention can be used to achieve the methods of the present invention.

[0009] The following are definitions of various terms and phrases used throughout this specification.

[0010] The term "aromatic-containing polymer" means a polymer, copolymer, or block polymer having at least one aromatic ring. Non-limiting examples of polymers include polystyrene, polymethylstyrene, and copolymers of styrene with at least one other monomer such as α-methylstyrene, butadiene, isoprene, acrylonitrile, methyl acrylate, methyl methacrylate, maleic anhydride, and / or an olefin (e.g., ethylene or propylene). Examples of suitable copolymers include those formed from acrylonitrile, butadiene, and styrene, copolymers of acrylic esters, styrene, and acrylonitrile, copolymers of styrene and α-methylstyrene, copolymers of propylene, diene, and styrene, aromatic polyethers, particularly polyphenylene oxide, aromatic polycarbonates, aromatic polyesters, aromatic polyamides, polyphenylene, polyxylylene, polyphenylene vinylene, polyphenylene ethynylene, polyphenylene sulfide, polyaryl ether ketone, aromatic polysulfone, aromatic polyether sulfone, aromatic polyimide, and mixtures thereof, and optionally copolymers with aliphatic compounds. Suitable substituents on the phenyl ring include C1-C4 alkyl groups such as methyl or ethyl, C1-C4 alkoxy groups such as methoxy or ethoxy, and / or aromatic moieties fused to the ring, including phenyl, biphenyl, and naphthyl, and aromatic moieties bonded to the phenyl ring through one or two carbon atoms. Suitable substituents on the vinyl group include C1-C4 alkyl groups such as methyl, ethyl, n- or iso-propyl, particularly methyl in the α-position. Suitable olefinic comonomers include ethylene, propylene, isoprene, isobutylene, butadiene, cyclohexadiene, cyclohexane, cyclopentadiene, optionally substituted norbornene, optionally substituted dicyclopentadiene, optionally substituted tetracyclododecene, dihydrocyclopentadiene, derivatives of maleic acid, preferably maleic anhydride, and derivatives of acrylonitrile, preferably acrylonitrile and methacrylonitrile.

[0011] The aromatic-containing polymer can have a (weight average) molecular weight Mw of 1,000 to 10,000,000, preferably 60,000 to 1,000,000, most preferably 70,000 to 600,000, and particularly 100,000 to 300,000, as determined by gel permeation chromatography (GPC) equipped with a light scattering, refractive index, and UV detector.

[0012] The aromatic-containing polymer can have a linear structure or can have branching points due to copolymer units (e.g., graft copolymers). The center of the branching can include star or branched polymers or can include other geometric forms of primary, secondary, tertiary, or optionally quaternary polymer structures. The copolymer can be a random copolymer or a block copolymer. Block copolymers include diblock, triblock, multiblock, and star block copolymers.

[0013] The term "hydrogenation activity" is intended to mean the hydrogenation rate of the polymer per hour, measured in moles of aromatic rings per gram of catalytic metal, at a specific reaction temperature, pressure, and / or polymer concentration.

[0014] The term "nanoparticle" means particles that exist on the nanometer (nm) scale with a diameter from 1 nm to 1000 nm.

[0015] The term "nonpolar" solvent is intended to mean a solvent having a dielectric constant of less than 5 (see, e.g., Brown et al., "Organic Chemistry," 8th ed., 2018, pages 389 - 390) and being stable under hydrogenation conditions. Non-limiting examples of nonpolar solvents include cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, cycloheptane, dodecane, isopentane, decahydronaphthalene, or mixtures thereof.

[0016] The term "polar" solvent is intended to mean a solvent having a dielectric constant greater than 7.6 and being stable under hydrogenation conditions. Non-limiting examples of polar solvents include dichloromethane, 1,2-dichloroethane, or mixtures thereof.

[0017] The term "stable to hydrogenation" is intended to mean a composition (e.g., an aromatic solvent) that does not react with hydrogen at 100 °C to 220 °C and at a pressure of 3.4 MPa to 7 MPa.

[0018] The terms "about" or "approximately" are defined as being close, as would be understood by one of ordinary skill in the art. In a non-limiting embodiment, such terms are defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0019] The terms "weight % (wt.%)", "volume % (vol.%)", or "mole % (mol.%)" are intended to mean, respectively, the weight percentage, the volume percentage, or the mole percentage of the component based on the total weight, the total volume, or the total number of moles of the material containing the component. As a non-limiting example, 10 g of a component in 100 g of a material is 10 weight %.

[0020] The term "substantially" and variations thereof are defined to include ranges within 10%, 5%, 1%, or 0.5%.

[0021] When used in the claims and / or the specification, "inhibit", or "reduce", or "prevent", or "avoid", or various variations of these terms include a measurable decrease or complete inhibition to achieve the desired result.

[0022] The term "effective", when such term is used in this specification and / or the claims, means sufficient to achieve the desired result, the expected result, or the intended result.

[0023] The use of the singular form “a” or “an” in combination with any of the terms “comprising,” “including,” “containing,” or “having” in the claims or specification may mean “one,” but is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

[0024] The terms “comprising” (and any form of comprising such as “comprises,” “comprises,” etc.), “having” (and any form of having such as “have,” “has,” etc.), “including” (and any form of including such as “includes,” “include,” etc.), or “containing” (and any form of containing such as “contains,” “contain,” etc.) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0025] The methods of the present invention can “comprise,” “consist essentially of,” or “consist of” the specific components, elements, compositions, etc. disclosed throughout this specification. With respect to the transitional phrase “consist essentially of,” in one non-limiting aspect, the basic and novel feature of the methods of the present invention is the ability to increase the hydrogenation rate of aromatic-containing polymers to produce fully hydrogenated or partially hydrogenated aromatic-containing polymers. This can be done substantially without or without any polymer degradation of the hydrogenated or partially hydrogenated polymer.

[0026] Other objects, features, and advantages of the present invention will become apparent from the following drawings, detailed description, and examples. However, it should be understood that these drawings, detailed description, and examples are provided by way of illustration only and are not intended to be limiting. Further, it is contemplated that changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features derived from a particular embodiment can be combined with features derived from other embodiments. For example, features derived from one embodiment may be combined with features derived from any of the other embodiments. In further embodiments, additional features may be added to the particular embodiments described herein.

[0027] [Brief Description of the Drawings] The advantages of the present invention will become apparent to those skilled in the art by reference to the following detailed description and the accompanying drawings.

[0028] Figure 1 is an explanatory diagram of a reactor system for producing a hydrogenated or partially hydrogenated aromatic-containing polymer using the solvent system of the present invention.

[0029] Figure 2 is a photograph showing the solubility of PVCH in the solvent system of the present invention and 100% dichloromethane.

[0030] Figure 3 is an explanatory diagram of the heterogeneous catalytic hydrogenation reaction rate of polystyrene (PS) using cyclohexane as a comparative solvent and the heterogeneous catalytic hydrogenation reaction rate of polystyrene (PS) using the mixed solvent of the present invention containing cyclohexane and dichloromethane (DCM) at a volume ratio of 1:1. Both solutions had a polymer content of 8 wt%, a Pt / Al 2 O 3 catalyst content of 0.45 wt%, a PS:catalyst ratio of 10:1, a temperature of 120 °C, and a pressure of 1000 psig (6.98 MPa).

[0031] Figure 4 is a diagram showing the time until 100% conversion in the hydrogenation treatment with a heterogeneous catalyst of PS as a function of the dichloromethane concentration (8% by weight of the polymer, Pt / Al 2 O 3 catalyst 0.45% by weight, PS:catalyst ratio is 10:1, 140 °C, 1000 psig (6.98 (MPa)).

[0032] Although various modifications and alternative forms are permitted in the present invention, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be to scale.

[0033] [Detailed Description of the Invention] At least one solution to the problems associated with the hydrogenation of aromatic-containing polymers has been discovered. This solution includes a cost-effective solvent system that can increase the production amount of the hydrogenated aromatic-containing polymer. Such a solvent system includes a polar solvent having a dielectric constant of at least 7.6 at 25 °C and a non-polar solvent having a dielectric constant of less than 5 at 25 °C in a volume ratio of polar solvent to non-polar solvent of 10:90 to 80:20. Without wishing to be bound by theory, the addition of the polar solvent is thought to increase the mass transfer between the catalyst and the polymer, while the non-polar solvent solubilizes the hydrogenation product so that the hydrogenation product does not precipitate from the solution upon cooling of the reaction mixture.

[0034] These and other non-limiting aspects of the present invention will be described in more detail in the following sections.

[0035] A. Solvent System The solvent system of the present invention includes a polar solvent and a nonpolar solvent. The polar solvent has a dielectric constant of at least 7.6 at 25 °C, preferably 7.6 to 11 at 25 °C. Non-limiting examples of dielectric constant values include 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, and any value or range therebetween. Non-limiting examples of polar solvents include dichloromethane and 1,2-dichloroethane. Dichloromethane has a dielectric constant of 8.93 at 25 °C. 1,2-Dichloroethane has a dielectric constant of 10.36 at 25 °C. The polar solvent does not include tetrahydrofuran or methyltetrahydrofuran. Non-limiting examples of nonpolar solvents include cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, cycloheptane, dodecane, isopentane, decahydronaphthalene, or mixtures thereof. The volume ratio of the polar solvent to the nonpolar solvent is 10:90 to 80:20, or 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, or any value or range therebetween. The solvent system includes any mixture of the nonpolar solvent and the polar solvent as long as the volume ratio of the nonpolar solvent to the polar solvent is maintained and / or the polar solvent has a dielectric constant exceeding 7.6 at 25 °C. Non-limiting examples of the solvent system include a mixture of dichloromethane and cyclohexane, a mixture of dichloromethane and methylcyclohexane, a mixture of dichloromethane and ethylcyclohexane, a mixture of dichloromethane and cyclooctane, a mixture of dichloromethane and cycloheptane, a mixture of dichloromethane and dodecane, a mixture of dichloromethane and isopentane, or a mixture of dichloromethane and decahydronaphthalene.In another example, the solvent system includes a mixture of 1,2-dichloroethane and cyclohexane, a mixture of 1,2-dichloroethane and methylcyclohexane, a mixture of 1,2-dichloroethane and ethylcyclohexane, a mixture of 1,2-dichloroethane and cyclooctane, a mixture of 1,2-dichloroethane and cycloheptane, a mixture of 1,2-dichloroethane and dodecane, a mixture of 1,2-dichloroethane and isopentane, or a mixture of 1,2-dichloroethane and decahydronaphthalene. Other combinations of solvents (e.g., combinations of 3, 4, 5, 6, 7, 8, 9, 10, 15, 20 solvents, etc.) are also within the scope of the present invention. When using the solvent system of the present invention, the hydrogenation reaction rate can be increased by 1 time, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times or more compared to the hydrogenation reaction rate of the same reaction using only a non-polar solvent. The solvent system of the present invention completely solubilizes or at least partially solubilizes an aromatic-containing polymer, a hydrogenated aromatic-containing polymer, a partially hydrogenated aromatic-containing polymer, or a combination thereof. The solvent system does not contain a solvent that is not stable to the hydrogenation reaction. For example, aromatic solvents such as benzene, toluene, naphthalene, xylene, or mixtures thereof. Usually, the polymer concentration in the solvent system of the present invention is 5 wt% to 20 wt%, or 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt% or any range or value therebetween.

[0036] B. Method for Hydrogenating Aromatic-Containing Polymers Figure 1 shows a schematic diagram of a process for hydrogenating an aromatic-containing polymer using the solvent system of the present invention. In some embodiments, the process is a heterogeneous reaction. Reactor 100 has an inlet 102 for polymer reactant supply, H 2It may include an inlet 104 for reactant supply, an inlet 102, a reaction region 106 configured to be in fluid communication with inlets 102 and 104, and an outlet 108. The outlet 108 may be configured to be in fluid communication with the reaction region 106 and to remove a product stream from the reaction region. The reactor 100 may be any reactor suitable for carrying out the hydrogenation of the polymer (e.g., a batch reactor or a continuous reactor). The reaction region 106 can contain any catalyst capable of hydrogenating the aromatic-containing polymer. The feed polymer reactant can enter the reaction region 106 via inlet 102. The feed reactant can be a mixture of the solvent system of the present invention and the aromatic-containing polymer. In one aspect, the solvent system is dichloromethane and cyclohexane, and the aromatic-containing polymer is a polystyrene-based resin. The mass ratio of the solvent to the polymer can be 4:1, 9:1, 19:1, or any range or value therebetween. Feed H 2 The reactant can enter the reactor 100 after purging the reactor with nitrogen through inlet 104. In the reaction region 106, the hydrogenation catalyst can be dispersed in the solvent system, and the aromatic-containing polymer can be completely solubilized or at least partially solubilized in the solvent system. The pressure of the reactor 100 is H 2It can be maintained by the supply of reactants. The product stream can be removed from the reaction zone 106 via the product outlet 108. The product stream can be sent to other processing units, stored, and / or transported. The product stream contains at least one hydrogenated aromatic ring, at least one partially hydrogenated aromatic ring, or both, or a mixture thereof. For example, by hydrogenating polystyrene, poly(vinylcyclohexane) can be produced. There is no low molecular weight polymer due to the decomposition of the polymer in the produced polymer product. The hydrogenation activity can be at least 10 moles of aromatic rings per gram of catalyst metal (e.g., Pt, Pd, and / or Ru) per hour at a reaction temperature of 120 °C to 140 °C, a pressure of 6.9 MPa, and a polymer concentration of 8 wt%. The hydrogenation level can be at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or any range or value in between.

[0037] The temperature and pressure can be changed according to the reaction to be carried out. The temperature can range from 100 °C to about 220 °C, from 120 °C to 190 °C, from 150 °C to 180 °C, 190 °C, 200 °C, 210 °C, or 220 °C, or any value or range in between. The pressure (e.g., the pressure of H 2 ) can range from about 2.1 MPa to 7 MPa, from 3.45 MPa to 7 MPa, or 2.1, 2.5, 3.0, 3.1, 3.2, 3.3, 3.4, 3.45, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0 or any range or value in between. The pressure of the reaction can be maintained by the pressure of hydrogen.

[0038] The reactor 100 can include one or more heating and / or cooling devices (e.g., insulation, electric heaters, jacketed heat exchangers) or control devices (e.g., computers, flow valves, automation valves, etc.) that can be used to control the reaction temperature and pressure of the reaction mixture. Only one reactor is shown, but it should be understood that multiple reactors can be housed in one unit or multiple reactors can be housed in one reactor unit. In some embodiments, a series of physically separated reactors equipped with inter-stage cooling / heating devices including heat exchangers, furnaces, firing heaters, etc. can be used.

[0039] C. Catalyst The catalyst of the present invention can include commercially available catalysts that can catalyze the hydrogenation of aromatic-containing polymers. Non-limiting examples of the catalyst include Sigma-Aldrich® (USA), Unicat (USA), BASF (Germany), Johnson Matthey (UK), Evonik (Germany), Clariant (Switzerland), etc. The catalyst includes one or more catalyst metals. In some aspects, the catalyst includes platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rd), or any combination thereof. In some embodiments, the catalyst is a bimetallic catalyst or a trimetallic catalyst. The bimetallic catalyst can include Pt, Pd, Ru, Rd combined with nickel (Ni), iridium (Ir), iron (Fe), copper (Cu), silver (Ag) metal or a combination thereof. The catalyst may or may not be supported. Non-limiting examples of the support include silica (SiO 2 ), alumina (Al 2 O 3 ), or titania (TiO 2 ), or a combination thereof. In some aspects, the catalyst is Pt / Al 2 O 3 , Pt / SiO 2 , or Pt / Al 2 O 3It is a catalyst. The percentage of the total weight of the metal in the supported catalyst can range from 40% by weight to 50% by weight, or 41% by weight, 42% by weight, 43% by weight, 44% by weight, 45% by weight, 46% by weight, 47% by weight, 48% by weight, 49% by weight, or 50% by weight.

[0040] In one embodiment, the catalyst comprises 0.05% by weight to 0.9% by weight of Pt nanoparticles and 99.1% by weight to 99.95% by weight of TiO based on the total weight of the catalyst. 2 0.20% by weight to 0.60% by weight of Pt nanoparticles and 99.4% by weight to 99.8% by weight of TiO. 2 Or, 0.25% by weight to 0.50% by weight of Pt nanoparticles and 99.5% by weight to 99.75% by weight of TiO. 2 It may contain. Such a catalyst has a pore volume of 0.01 cm 3 / g to 0.35 cm 3 / g, preferably 0.03 cm 3 / g to 0.30 cm 3 / g, more preferably 0.05 cm 3 / g to 0.25 cm 3 / g, a surface area of 5 m 2 / g to 80 m 2 / g, preferably 5 m 2 / g to 40 m 2 / g, more preferably 5 m 2 / g to 20 m 2 / g, and / or a median pore diameter of less than 300 microns, preferably less than 100 microns.

[0041] In one embodiment, the catalyst comprises 0.05% by weight to 0.9% by weight of platinum nanoparticles and 99.1% by weight to 99.95% by weight of SiO based on the total weight of the catalyst. 2 0.20% by weight to 0.60% by weight of platinum nanoparticles and 99.4% by weight to 99.8% by weight of SiO. 2 Or, 0.25% by weight to 0.50% by weight of platinum nanoparticles and 99.5% by weight to 99.75% by weight of SiO. 2 It contains. Such a catalyst has a pore volume of 0.01 cm 3 / g to 0.35 cm 3 / g, preferably 0.03 cm 3 / g to 0.30 cm 3 / g, more preferably 0.05 cm 3 / g to 0.25 cm 3 / g of pore volume, 5 m 2 / g to 80 m 2 / g, preferably 5 m 2 / g to 40 m 2 / g, more preferably 5 m 2 / g to 20 m 2 / g of surface area and / or has a median pore diameter of less than 300 microns, preferably less than 100 microns.

[0042] In one embodiment, the catalyst comprises 0.05 wt% to 0.9 wt% of Pt nanoparticles and 99.1 wt% to 99.95 wt% of Al 2 O 3 based on the total weight of the catalyst, 0.20 wt% to 0.60 wt% of platinum nanoparticles and 99.4 wt% to 99.8 wt% of Al 2 O 3 or 0.25 wt% to 0.50 wt% of platinum nanoparticles and 99.5 wt% to 99.75 wt% of Al 2 O 3 It contains. Such a catalyst has a pore volume of 0.01 cm 3 / g to 0.35 cm 3 / g, preferably 0.03 cm 3 / g to 0.30 cm 3 / g, more preferably 0.05 cm 3 / g to 0.25 cm 3 / g, 5 m of pore volume 2 / g to 80 m 2 / g, preferably 5 m 2 / g to 40 m 2 / g, more preferably 5 m 2 / g to 20 m 2 / g of surface area and / or has a median pore diameter of less than 300 microns, preferably less than 100 microns.

[0043] 〔Examples〕 The present invention will be described in more detail with reference to the following specific examples. The following examples are provided for illustrative purposes only and are not intended to limit the present invention in any way. Those skilled in the art will readily recognize various non-essential parameters that can be changed or modified to obtain essentially the same results.

[0044] Examples 1 - 5 (Hydrogenation reaction of polystyrene using the solvent system of the present invention) Pt / Al prepared according to International Publication WO2022 / 013751 by Wu et al. 2 O 3 catalyst (0.45 wt% platinum, polystyrene / catalyst ratio 10:1) was placed in a stainless steel reactor (Parr Series 5000 Multiple Reactor System, Parr Instrument Company, 100 mL) together with the desired volume of cyclohexane and dichloromethane (total 30 mL, solvent) and polystyrene (PS - 155, SABIC® (Saudi Arabia), weight average molecular weight M w = 235,000, 8 wt%). The reactor was first purged three times with N 2 and then three times with H 2 to remove air and moisture, and then filled with high - pressure H 2 to the desired reaction pressure, about 500 and 1000 psi (3.4 MPa - 6.9 MPa). After reaching the desired pressure, the contents of the reactor were heated at a rate of 1 °C / min to the set temperature of 120 °C and maintained at the final set temperature for several hours. After the reaction was completed, the reactor was cooled to room temperature, the pressure was discharged to atmospheric pressure (101 kPa), the contents of the reactor were recovered, and the solid catalyst was separated from the polymer solution using centrifugation or filtration. The time until the conversion rate reached 100% was 1 hour.

[0045]

Table 1

[0046] Examples 6 - 10 (Hydrogenation of Polystyrene Using the Solvent System of the Present Invention) The procedure of Example 1 was used except that the reaction temperature was raised to 140 °C and the desired volume ratio of cyclohexane to dichloromethane was used. Table 2 summarizes the amounts of dichloromethane and cyclohexane used and the time to reach 100% conversion and produce poly(vinylcyclohexane) (PVCH).

[0047] [Table 2]

[0048] The solubility of PVCH reported for Examples 13 and 14 was determined by physically blending PVCH with dichloromethane and cyclohexane at a suitable volume ratio. Based on the data of Examples 12 and 15, one skilled in the art of hydrogenation would expect the reaction time to be similar to that of Examples 12 and 15. As shown in Figure 2, and Tables 1 and 2, the solubility of the PVCH product was a function of the solvent composition. When the reaction mixture was cooled to room temperature, it was observed that the product PVCH was insoluble in 100% DCM solvent. Referring to Figure 2, when the DCM solvent concentration exceeded 80% by volume, the PVCH product became insoluble when cooled to ambient temperature or near it.

[0049] Comparative Example A (Hydrogenation of Polystyrene Using Cyclohexane) The procedure of Example 1 was followed except that cyclohexane was used as the solvent (i.e., no polar solvent was used). In Comparative Example A, the polystyrene conversion was 100% after 3.28 hours at 120 °C.

[0050] Comparative Example B (Hydrogenation of Polystyrene Using Cyclohexane) The procedure of Examples 6 to 10 was followed except that cyclohexane was used as the solvent (i.e., no polar solvent was used). In Comparative Example B, the polystyrene conversion rate was 100% after 1.33 hours at 140°C.

[0051] Figure 3 is a graph of the hydrogenation rates of Example 3 and Comparative Example A. The upper line is the hydrogenated polystyrene conversion rate (PS conversion rate %) versus time for the cyclohexane / dichloromethane solvent system of Example 3. The lower line is the hydrogenated polystyrene conversion rate (PS conversion rate %) versus time for Comparative Example A using only cyclohexane as the solvent. As shown in Figure 2, when the solvent system of the present invention (for example, Example 3 with a volume ratio of cyclohexane to dichloromethane of 1:1) was used in the hydrogenation process of polystyrene, a significant increase in the reaction rate (i.e., a significant decrease in the time to reach 100% conversion (2.1 times)) was observed compared to the case using cyclohexane (Comparative Example B). Notably, due to the increase in activity, the hydrogenation reaction using the solvent system of the present invention was completed in less than 2 hours at a temperature of 120°C.

[0052] Figure 4 shows the time-dependence of the achievement of 100% conversion of polystyrene to PVCH during the hydrogenation process based on the volume concentration of dichloromethane in the solvent system of the present invention (a mixture of cyclohexane and dichloromethane) at 140°C. A sharp decrease was observed from 1.33 hours at 0 vol.% dichloromethane (pure cyclohexane, Comparative Example B) to 0.85 hours at 50 vol.% dichloromethane (Example 8). Notably, due to the increase in activity, the hydrogenation reaction using the solvent system of the present invention was completed in less than 1 hour at a temperature of 140°C.

[0053] Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of the embodiments defined by the appended claims. Further, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, products, compositions of matter, means, methods, and steps described herein. As will be readily understood by those skilled in the art, from the above disclosure, processes, machines, products, compositions of matter, means, methods, or steps that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein, whether currently existing or later developed, can be utilized. Accordingly, the appended claims are intended to include such processes, machines, products, compositions of matter, means, methods, or steps within their scope.

Brief Description of the Drawings

[0054]

Figure 1

Figure 2

Figure 3

Figure 4

Claims

1. A method for hydrogenating an aromatic-containing polymer, The method comprises contacting an aromatic polymer solution and a hydrogenation catalyst in the presence of hydrogen (H ２ 2) gas at a temperature of 100 °C to 220 °C, a pressure of 3.4 MPa to 7 MPa, or a combination thereof, to produce a polymer composition comprising at least one hydrogenated aromatic ring and / or at least one partially hydrogenated aromatic ring. wherein the aromatic polymer solution contains an aromatic-containing polymer, a polar solvent having a dielectric constant exceeding 7.6 at 25°C, and a non-polar solvent having a dielectric constant of 5 or less at 25°C, and the volume ratio of the polar solvent to the non-polar solvent is in the range of 10:90 to 80:

20.

2. wherein the aromatic-containing polymer is polystyrene, and the hydrogenated or partially hydrogenated polymer contains poly(vinylcyclohexane), the method according to claim 1.

3. The method according to any one of claims 1 to 2, wherein the non-polar solvent is cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, cycloheptane, dodecane, isopentane, decahydronaphthalene, or a mixture thereof.

4. The method according to any one of claims 1 to 3, wherein the polar solvent has a dielectric constant of 7.6 to 11, preferably 9.

5. The method according to any one of claims 1 to 4, wherein the polar solvent is dichloromethane, 1,2-dichloroethane, or a combination thereof.

6. The method according to any one of claims 1 to 5, wherein the non-polar solvent is cyclohexane and the polar solvent is dichloromethane.

7. The method according to any one of claims 1 to 6, wherein the volume ratio of the polar solvent to the non-polar solvent is 20:80 to 80:20, more preferably 30:70 to 70:

30.

8. The method according to any one of claims 1 to 7, wherein the hydrogenation reaction rate is more than 1-fold, preferably 2-fold, more preferably 2.5-fold, and even more preferably 5-fold higher than the hydrogenation reaction rate under the same reaction conditions without using the polar solvent.

9. The method according to any one of claims 1 to 8, wherein the contact conditions include a temperature of 120°C to 140°C and a pressure of 3.4 MPa to 6.9 MPa.

10. The method according to any one of claims 1 to 9, wherein the hydrogenation catalyst contains platinum (Pt), palladium (Pd), ruthenium (Ru), or any combination thereof, or an alloy thereof.

11. The method according to any one of claims 1 to 10, wherein the hydrogenation catalyst contains a carrier.

12. The carrier is silica (SiO ２ ), alumina (Al ２ O ３ ), or titania (TiO ２ ), or any combination thereof, the method according to claim 11.

13. The method according to any one of claims 1 to 12, wherein the hydrogenated or partially hydrogenated polymer composition does not contain or substantially does not contain a polymer scission composition. **Claim 14** The method according to any one of claims 1 to 13, wherein the aromatic polymer is completely solubilized or at least partially solubilized in a solvent. **Claim 15** The method according to any one of claims 1 to 14, wherein the concentration of the polymer in the polymer solution is 5% by weight to 20% by weight, preferably 8% by weight.

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