KR20240112619A - A bimetal catalyst for aromatic polymer containing an ester group decomposition reaction and method for producing alkyl aromatic hydrocarbons in high yield and high selectivity from aromatic polymer containing an ester group using the catalyst - Google Patents

Abstract

The present invention relates to a bimetallic catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group and a method for selectively producing alkyl aromatic hydrocarbons from an aromatic polymer containing an ester functional group using the catalyst. In detail, it relates to two specific types of alkyl aromatic hydrocarbons. A bimetallic catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group capable of efficiently producing alkylaromatic hydrocarbons from an aromatic polymer containing an ester functional group using a bimetallic catalyst containing an active metal, and an ester functional group using the catalyst. It relates to a method of producing alkyl aromatic hydrocarbons with high yield and high selectivity from aromatic polymers containing the same.

Description

A bimetal catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group and a method for producing alkyl aromatic hydrocarbons with high yield and high selectivity from an aromatic polymer containing an ester functional group using the catalyst {A bimetal catalyst for aromatic polymer containing an ester group decomposition reaction and method for producing alkyl aromatic hydrocarbons in high yield and high selectivity from aromatic polymer containing an ester group using the catalyst}

The present invention relates to a bimetallic catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group and a method for producing alkyl aromatic hydrocarbons with high yield and high selectivity from an aromatic polymer containing an ester functional group using the catalyst, specifically, A bimetallic catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group capable of efficiently producing alkylaromatic hydrocarbons from an aromatic polymer containing an ester functional group using a bimetallic catalyst containing two specific types of active metals, and the catalyst It relates to a method for producing alkyl aromatic hydrocarbons with high yield and high selectivity from an aromatic polymer containing an ester functional group.

Plastics, which have been easily mass-produced from petroleum resources, are easy to control physical properties due to their structural diversity, so products made from these materials have met industrial needs and provided convenience in everyday life. However, as the amount of plastic discarded increases rapidly in proportion to the amount used, the need for recycling technology that circulates plastic into a reusable resource is emerging.

Among plastics discarded after consumption, aromatic polymers containing ester functional groups have the characteristic of being able to be returned to the raw material before synthesis through a relatively simple chemical reaction route such as decomposition or exchange of the ester functional group, and thus can be used for chemical recycling based on depolymerization. It is attracting attention as a material that can be repeatedly reused. In particular, among aromatic polymers containing the ester functional group, polyethylene terephthalate (PET) is used for a variety of purposes, from materials for electrical and electronic components and displays to disposable packaging containers, and has a diverse portfolio ranging from low-value-added products to high-value-added products, making it a valuable It is a polymer of high importance. In addition, polybutylene terephthalate (PBT), another example of an aromatic polymer containing an ester functional group, has excellent impact strength at low temperatures and can be used as a reinforcing material such as glass fiber or to manufacture reinforced composite products. It is used in electrical products because it has excellent electrical properties such as arc resistance, dielectric strength, and tracking resistance. Considering their importance, it is essential to secure recycling technology for aromatic polymers containing ester functional groups for sustainable industrial development and a virtuous cycle of resources.

To solve this problem, chemical recycling technology that decomposes plastic into monomers and then reprocesses it into polymers is being researched and developed, and is being pointed out as an ideal resource recycling technology due to the advantage of maintaining the physical properties of the repolymerized polymer. As an example of such chemical recycling, a reaction can be performed to decompose PET, a type of aromatic polymer containing an ester functional group that is widely used as a packaging material, into monomers. The PET decomposition reaction includes glycolysis, ammonolysis, methanolysis, and hydrolysis depending on the type of reactant, and is a complex process that utilizes the advantages of each process by combining them. Various chemical decomposition reactions are widely used.

Among the PET decomposition reactions listed above, methanolysis produces dimethyl terephthalate (DMT) and ethylene glycol (EG) as decomposition products, and glycolysis produces bis(2-hydroxyethylene terephthalate) (BHET) as a decomposition product. is created. Regarding the conversion technology of the decomposition product, Non-Patent Document 2 and Non-Patent Document 3 each convert cyclohexanedimethanol (CHDM) using DMT or BHET as a hydrogenation reactant in the presence of a RuPtSn/Al ₂ O ₃ catalyst. Manufacturing technology is disclosed.

In addition, hydrolysis, another type of PET decomposition reaction, generates terephthalic acid (TPA) and ethylene glycol (EG) as decomposition products. In relation to the conversion technology of TPA, in Non-Patent Document 1, Ru/Nb ₂ O ₅ catalyst A technology has been disclosed to hydrolyze PET in the presence of PET and convert it into hydrocarbons containing aromatics such as BTX. However, in the non-patent document 1, the further decomposition reaction of the hydrolysis product TPA is a rate-determining step in which hydrogenolysis and decarboxylation occur competitively, and as a result, among the hydrocarbons containing the aromatic A phenomenon showing higher selectivity for benzene and toluene than for xylene was observed.

Among the compounds belonging to hydrocarbons containing aromatics, BTX (benzene, toluene, and xylene) are important substances in the petrochemical field, but in particular, xylene is not only widely used as a solvent in the leather, rubber, and printing fields. In the case of oxidizing p-xylene, it is possible to obtain terephthalic acid (TPA), a monomer of PET, so securing technology for producing alkyl aromatic hydrocarbons such as xylene is urgently needed in terms of a virtuous cycle of resources.

Shenglu Lu et al., H2-free Plastic Conversion: Converting PET back to BTX by Unlocking Hidden Hydrogen, ChemSusChem, 2021, 14, pp.1-10 Xuefeng Li et al., One-Pot Conversion of Dimethyl Terephthalate into 1,4-Cyclohexanedimethanol with Supported Trimetallic RuPtSn Catalysts, Industrial & Engineering Chemistry Research, 2014, 53, pp.619-625 RSC Advance, 2016, 6, pp.48737-48744

The present invention provides a bimetallic catalyst suitable for the decomposition reaction of an aromatic polymer containing an ester functional group, and performs the decomposition reaction under the catalyst and optimized reaction conditions to produce an alkyl alkyl catalyst in high yield and high selectivity from an aromatic polymer containing an ester functional group. The purpose is to provide a method for producing aromatic hydrocarbons.

In order to solve the above problem, the bimetallic catalyst for aromatic polymer decomposition reaction containing an ester functional group of the present invention may be characterized by containing Pt and Sn as active metals.

The Pt-Sn active metal according to the present invention can be used while supported on an acidic support.

The molar ratio of Pt:Sn may be 1:0.05 to 1:3.0.

The amount of active metal supported in the catalyst may be 1.0 to 20 wt% based on the total weight of the catalyst.

The catalyst may be calcined at a temperature ranging from 200 to 800 °C.

In addition, the present invention relates to a method for producing alkyl aromatic hydrocarbons with high yield and high selectivity from an aromatic polymer containing an ester functional group, comprising the steps of (A) reducing a bimetallic catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group; ; (B) performing a decomposition reaction by contacting the reduced catalyst of step (A) with an aromatic polymer containing an ester functional group; and (C) obtaining an alkyl aromatic hydrocarbon from the decomposition reaction of the aromatic polymer containing an ester functional group in step (B).

In step (A), the reduction temperature of the catalyst may be in the range of 200 to 800 °C.

In step (B), the decomposition reaction of the aromatic polymer containing an ester functional group may include a hydrogenation decomposition reaction and a hydrogenation deoxygenation reaction.

The decomposition reaction of the aromatic polymer containing the ester functional group in step (B) may be performed in the range of 200 to 350 ° C.

The decomposition reaction of the aromatic polymer containing the ester functional group in step (B) may be performed at a hydrogen pressure in the range of 10 to 300 bar.

According to the present invention, an optimal bimetallic catalyst and reaction conditions for the decomposition reaction of an aromatic polymer containing an ester functional group are provided, and a high yield of alkyl aromatic hydrocarbons is selectively produced from an aromatic polymer containing an ester functional group under the catalyst and reaction conditions. It can be manufactured.

It is possible to recover highly versatile alkyl aromatic hydrocarbons from aromatic polymers containing ester functional groups using the catalyst and the method for producing alkyl aromatic hydrocarbons using the same.

In particular, when the aromatic polymer containing an ester functional group is PET, xylene can be selectively produced under the decomposition reaction conditions of the present invention, and the oxidation product of xylene is terephthalic acid (TPA), a monomer of PET. There is an advantage in that PET can be reproduced in an environmentally friendly manner without relying on petroleum-derived resources.

Figure 1 is a diagram showing the steps for manufacturing BTX from PET.
Figure 2 is a TEM measurement photo of a PtSn/Al ₂ O ₃ catalyst as an example of the present invention.
Figure 3 shows the XRD measurement results of catalysts with different types of active metals and molar ratios between active metals in the catalyst as an example of the present invention.
Figure 4 is a graph showing the PET conversion rate and BTX yield according to the type of active metal in the catalyst as an example of the present invention.
Figure 5 is a graph showing the PET conversion rate and BTX yield according to the molar ratio of Pt and Sn in the catalyst as an example of the present invention.
Figure 6 is a graph showing the PET conversion rate and BTX yield according to the metal loading amount of Pt and Sn in a PtSn/Al ₂ O ₃ catalyst with a Pt:Sn molar ratio of 1:0.5 as an example of the present invention.
Figure 7 is a graph showing PET conversion rate and BTX yield according to reaction time in the presence of catalyst in Preparation Example 4 as an example of the present invention.
Figure 8 shows an example of the present invention, showing products other than BTX (a: alkyl aromatic and cycloaliphatic other than BTX, b: benzoate and terephthalate, c: dimer product) according to reaction time in the presence of catalyst in Preparation Example 4 of the present invention. ) This is a graph showing the yield.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

Throughout the specification of the present application, when a part “includes” a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Figure 1 is a diagram showing the steps of manufacturing BTX from PET as an example of the manufacturing method according to the present invention. The chain of polyethylene terephthalate (PET), a type of aromatic polymer containing an ester functional group in the molten state, is decomposed into BHET (bis-hydroxyethyl terephthalate) and HEMBA (2-Hydroxyethyl 4-methylbenzoate) by hydrogenolysis. , ethylene glycol (EG) and water are produced as by-products. In addition, the BHET is converted into HEMBA through a hydrogenation decomposition reaction or converted into EMBA (Ethyl 4-methylbenzoate) through DET (diethyl terephthalate) through hydrogenation and deoxygenation.

The produced HEMBA and EMBA are converted to xylene through hydrogen decomposition reaction or converted to xylene or toluene through toluic acid. Benzene is produced through a single decarboxylation reaction from terephthalic acid, a hydrocracking product. In order to selectively produce xylene, the hydrogenation decomposition reaction of PET must be followed by the hydrogenation decomposition reaction of BHET and HEMBA. However, as the rate-determining step, the hydrogenation decomposition reaction and the hydrogenation deoxygenation reaction are performed competitively. The type of active metal in the catalyst can have an effect on the competition between the two reactions.

The present invention provides a catalyst for aromatic polymer decomposition reaction containing an ester functional group with optimal active metal species and a method for selectively producing alkyl aromatic hydrocarbons using the catalyst. The catalyst system according to the present invention is an active metal, and the Pt-Sn two-metal catalyst can selectively improve the production of alkyl aromatics compared to the catalyst having one metal of Pt or Sn or a three metal added to Pt-Sn. In addition, when the aromatic polymer containing the ester functional group is a terephthalate or isophthalate series, the production rate of xylene, which has excellent industrial utility, is significantly higher among the alkyl aromatics produced.

In addition, in the case of having the Pt-Sn dimetal, it provides optimal catalyst-related factors such as metal mixing ratio and supported amount, and also provides optimal reaction conditions when decomposing an aromatic polymer containing an ester functional group using the catalyst. You can.

Hereinafter, we will look at the bimetallic catalyst for aromatic polymer decomposition reaction containing an ester functional group of the present invention.

The bimetallic catalyst for aromatic polymer decomposition reaction containing an ester functional group of the present invention is characterized by containing Pt and Sn as active metals. Here, bi-metal means including Pt and Sn as active metals constituting the catalyst.

The catalyst of the present invention is useful in the decomposition reaction of aromatic polymers containing an ester functional group, and the aromatic polymers containing an ester functional group are dicarboxylic acids and diols (dialcohols) used as starting materials, or hydrides having both hydroxy groups and carboxylic acid groups. One or two or more oxycarboxylic acid compounds alone are used as starting materials and are produced through continuous condensation polymerization by dehydration, or they may have multiple ester bond structures in repeating units or at arbitrary positions in the polymer, where dicarboxylic acid compounds are used as starting materials. Ruboxylic acid consists of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethanedicarboxylic acid, trimellitic acid, pyromellitic acid, and combinations thereof. Di-alcohol is selected from the group, ethylene glycol, trimethylene glycol, 1,2-propanediol, tetramethylene glycol, neopentyl glycol, pentamethylene glycol, hexamethylene glycol, decane methylene glycol, dodecamethylene glycol, 1, 4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, di(tetramethylene) glycol, tri(tetramethylene) It is selected from the group consisting of glycol, polytetramethylene glycol, pentaerythritol, 2,2-bis (4-β-hydroxyethoxyphenyl) propane, and combinations thereof, and the hydroxycarboxylic acid compound is 4-hydroxybenzoic acid, 6- It may be selected from the group consisting of hydroxynaphthalene-2-carboxylic acid and combinations thereof.

Examples of aromatic polymers containing the ester functional group include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), Vectran, and combinations thereof. can be selected.

Preferably, the polymer containing the ester functional group is polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), and the starting material for producing the polymer may be terephthalic acid or a salt thereof, and alkylene glycol.

The Pt-Sn two-metal catalyst of the present invention may be used while supported on a support. The support can be any conventional support as long as it does not interfere with the decomposition of the aromatic polymer containing an ester functional group, and is preferably an acidic support, more preferably alumina.

Among the active metals, Pt is a metal precursor: (NH ₃ ) ₄ Pt(NO ₃ ) ₂ , PtCl ₂ , PtCl ₄ , (NH ₄ ) ₂ PtCl ₄ , (NH ₄ ) ₂ PtCl ₆ , K ₂ PtCl ₄ , K ₂ PtCl ₆ , Na ₂ PtCl ₆ , H ₂ PtCl ₆ and Pt(C ₅ H ₇ O ₂ ) ₂ (Pt(acac) ₂ ), Pt(NH ₃ ) ₂ Cl ₂ and Pt(NH ₃ ) ₄ Cl ₂ ·xH ₂ O, Pt(NH ₃ ) ₄ (OH) ₂ ·xH ₂ O can be used, and preferably (NH ₃ ) ₄ Pt(NO ₃ ) ₂ can be used.

In addition, SnCl ₄ ·5H ₂ O, SnF ₂ , SnBr ₄ , Sn(CH ₃ CO ₂ ) ₂ , Sn(OC(CH ₃ ) ₃ ) ₄ , SnC ₂ O ₄ can be used as the Sn metal precursor, Preferably, SnCl ₄ ·5H ₂ O can be used.

The molar ratio of Pt:Sn is 1:0.05 to 1:3.0, preferably 1:0.1 to 1:1.5, more preferably 1:0.2 to 1:1.2, and most preferably 1:0.4 to 1:1.2. It can be characterized as:

The amount of active metal supported in the catalyst may range from 1.0 to 20.0 wt%, preferably from 2.5 to 12.0 wt%, and more preferably from 3.5 to 10 wt%, based on the total weight of the catalyst.

The content of Sn in the catalyst may range from 15 to 200%, preferably from 25 to 200%, and more preferably from 50 to 200%, relative to the content of Pt.

The catalyst may be calcined at a temperature ranging from 200 to 800 °C, preferably 450 to 650 °C.

Additionally, the present invention can provide a method for producing alkyl aromatic hydrocarbons with high yield and high selectivity from an aromatic polymer containing an ester functional group using the catalyst.

According to the present invention, a method for producing an alkyl aromatic hydrocarbon with high yield and high selectivity from an aromatic polymer containing an ester functional group includes the steps of (A) reducing a catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group; (B) performing a decomposition reaction by contacting the reduced catalyst of step (A) with an aromatic polymer containing an ester functional group; and (C) obtaining an aromatic hydrocarbon containing xylene from the decomposition reaction of the aromatic polymer containing an ester functional group in step (B).

In step (A), the reduction temperature of the catalyst may be in the range of 200 to 800 °C, preferably 300 to 700 °C, more preferably 400 to 600 °C, and most preferably 400 to 550 °C.

In step (B), the decomposition reaction of the aromatic polymer containing an ester functional group includes a hydrogenation decomposition reaction and a hydrogenation deoxygenation reaction. The two reactions are performed competitively, and the catalytically active metal is generated in the competition between the two reactions. It can have an impact.

The decomposition reaction of the aromatic polymer containing the ester functional group in step (B) is carried out at 200 to 350 ° C, preferably 225 to 325 ° C, more preferably 250 to 300 ° C, even more preferably 270 to 295 ° C, most preferably Can be carried out under heating conditions ranging from 285 to 295 °C.

In addition, the decomposition reaction of the aromatic polymer containing the ester functional group in step (B) is performed at a hydrogen pressure of 10 to 300 bar, preferably 10 to 100 bar, more preferably 25 to 70 bar, as converted to pressure at room temperature. Preferably, it may be performed under pressurized conditions in the range of 35 to 60 bar.

The aromatic hydrocarbons obtained in step (C) include aromatics in which an alkyl group, such as benzene, is not substituted, and alkyl aromatic hydrocarbons in which an alkyl group is substituted. The alkyl aromatic hydrocarbons include a single aromatic benzene ring or a fused aromatic benzene ring in the structure. It is a hydrocarbon containing a compound in which at least one alkyl group is substituted in place of at least one hydrogen atom connected to the benzene ring. Examples of the alkyl aromatic hydrocarbon include monoalkylbenzene including toluene, and xylene. Including dialkylbenzene, trialkylbenzene, tetraalkylbenzene, pentaalkylbenzene, monoalkylnaphthalene, dialkylnaphthalene, but is not limited to the exemplary compounds described.

Hereinafter, a preferred embodiment of the bimetallic catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group of the present invention and a method for producing alkyl aromatic hydrocarbons with high yield and high selectivity from an aromatic polymer containing an ester functional group using the catalyst will be described. Let's take a look. For reference, the following examples are provided to illustrate one or more preferred embodiments of the present invention, but the present invention is not limited to those embodiments. Numerous changes may be made to the examples below that remain within the scope of the invention.

<Comparative Preparation Examples 1 to 6 and Preparation Examples 1 to 12: Catalyst Preparation>

The catalyst mixture containing 20 mL of degassed distilled water and 1.8 g of the metal precursor and support shown in Table 1 below was added to the catalyst mixture for 60 minutes in an ultrasonic bath at room temperature and dried on a hot plate at 80°C. . The dried catalyst composition was further dried in an oven at 120°C for 12 hours, then heated to 500°C at a rate of 5°C/min while injecting air in a tubular furnace, and then calcined at 500°C for 4 hours to ensure that the active metal was not contained in the alumina. A catalyst in this form was prepared.

number Precursor mass (g) Pt:Ru:Sn
molar ratio Metal loading amount (wt.%) Support (g) Total Pt Ru Sn type mass Pt
Precursor ^* Ru
Precursor ^** Sn
Precursor ^*** Comparative Manufacturing Example 1 0.188 - - 1:0:0 5.0 5.0 - - γ-Al ₂ O ₃ 1.8 Comparative Manufacturing Example 2 - 0.245 - 0:1:0 5.0 - 5.0 - γ-Al ₂ O ₃ 1.8 Comparative Manufacturing Example 3 - - 0.280 0:0:1 5.0 - - 5.0 γ-Al ₂ O ₃ 1.8 Comparative Manufacturing Example 4 0.124 0.084 - 1:1:0 5.0 3.3 1.7 - γ-Al ₂ O ₃ 1.8 Comparative Manufacturing Example 5 - 0.113 0.151 0:1:1 5.0 - 2.3 2.7 γ-Al ₂ O ₃ 1.8 Comparative Manufacturing Example 6 0.089 0.060 0.080 1:1:1 5.0 2.4 1.2 1.4 γ-Al ₂ O ₃ 1.8 Manufacturing Example 1 0.156 - 0.047 1:0:0.33 5.0 4.2 - 0.8 γ-Al ₂ O ₃ 1.8 Manufacturing example 2 0.085 - 0.038 1:0:0.50 3.0 2.3 - 0.7 γ-Al ₂ O ₃ 1.8 Manufacturing example 3 0.114 - 0.052 1:0:0.50 4.0 3.1 - 0.9 γ-Al ₂ O ₃ 1.8 Manufacturing example 4 0.144 - 0.065 1:0:0.50 5.0 3.8 - 1.2 γ-Al ₂ O ₃ 1.8 Manufacturing example 5 0.175 - 0.079 1:0:0.50 6.0 4.6 - 1.4 γ-Al ₂ O ₃ 1.8 Manufacturing example 6 0.190 - 0.057 1:0:0.33 6.0 5.0 - 1.0 γ-Al ₂ O ₃ 1.8 Manufacturing example 7 0.191 - 0.087 1:0:0.50 6.5 5.0 - 1.5 γ-Al ₂ O ₃ 1.8 Manufacturing example 8 0.194 - 0.176 1:0:1.00 8.0 5.0 - 3.0 γ-Al ₂ O ₃ 1.8 Manufacturing example 9 0.117 - 0.106 1:0:1.00 5.0 3.1 - 1.9 γ-Al ₂ O ₃ 1.8 Production example 10 0.085 - 0.154 1:0:2.00 5.0 2.3 - 2.7 γ-Al ₂ O ₃ 1.8 Manufacturing example 11 0.144 - 0.065 1:0:0.50 5.0 3.8 - 1.2 _ZnTiO3 1.8 Manufacturing example 12 0.144 - 0.065 1:0:0.50 5.0 3.8 - 1.2 SiO ₂ 1.8 *Pt precursor: (NH ₃ ) ₄ Pt(NO ₃ ) ₂ , **Ru precursor: RuCl ₃ ·3H ₂ O, ***Sn precursor: SnCl ₄ ·5H ₂ O

<Catalyst TEM measurement results>

To evaluate the properties of the catalyst prepared in Preparation Example 4, TEM and HAADF-STEM (Titan cube G2 60-300, ThermoFisher, USA) were measured, and the results are shown in FIG. 2.

Figure 2 is a TEM measurement photo of a PtSn/Al ₂ O ₃ catalyst as an example of the present invention.

Referring to Figure 2, it can be seen that Pt and Sn are well dispersed in the Al ₂ O ₃ support. In particular, Pt was confirmed to be evenly dispersed as crystalline nanoparticles of 2-4 nm in size with a (111) plane.

<Catalyst XRD measurement results>

To evaluate the properties of the catalysts prepared in Preparation Examples 1, 4, 9, 10 and Comparative Preparation Examples 1 and 3, XRD (Aeris, manufactured by Malvern Panalytical Ltd, UK) was used from 20° to 90° (2theta, degree). The results of measurement at a speed of 1° per minute are shown in Figure 3.

Figure 3 shows the XRD measurement results of catalysts with different types of active metals and molar ratios between active metals in the catalyst as an example of the present invention.

Referring to Figure 3, it can be seen that Pt is well dispersed in the Al ₂ O ₃ support in nanoparticle size, and as the Sn content increases, Pt ₃ Sn alloy is formed. In particular, Preparation Example 1 (Pt/Sn=1/0.33) and Preparation Example 4 (Pt/Sn=1/0.50) contain both Pt and Pt ₃ Sn alloy, but Preparation Example 9 (Pt) has a Pt/Sn content ratio of 1.0 or less. /Sn=1/1) and Preparation Example 10 (Pt/Sn=1/2) confirmed that Pt was rapidly converted to Pt ₃ Sn alloy.

<Hydrogenolysis reaction of PET in the presence of a two-metal catalyst>

1.6 g of the catalyst of the comparative preparation or preparation example shown in Table 2 below was placed in a tubular furnace, the temperature was raised from room temperature to 400°C to 700°C while injecting 5% H ₂ /N ₂ , and the temperature was reduced to room temperature after reduction for 4 hours. After lowering it, air is injected to passivate it.

The passivated catalyst was placed in a 100 mL autoclave reactor (Autoclave, manufactured by Parr) with 16.0 g of polyethylene terephthalate (PET, manufactured by Lotte Chemical) and 0.5 g of hexadecane (made by Hexadecane, Internal Standard) cut into pieces of 0.5 cm × 0.5 cm. After inputting the reactor, it was pressurized using 50 bar hydrogen and purged three times to remove oxygen and moisture in the reactor.

After filling the hydrogen pressure to 20 bar to 50 bar at room temperature, the reactor was heated, and stirring was started when the temperature inside the reactor increased above 150°C. The hydrogenation reaction was performed for 12 to 24 hours starting at an internal temperature of 260 ℃ to 300 ℃ in the reactor. The hydrogen pressure in the reactor was controlled using a high-pressure MFC (Mass flow controller), and hydrogen could be supplied as much as consumed during the reaction. It was allowed to happen.

After the hydrogenation reaction is completed, the reactor is rapidly cooled, the product is separated from unreacted PET and catalyst using acetone, the mass of dried unreacted PET is measured to calculate the conversion rate, and BTX and by-products are extracted using GC. The results of calculating the yield are shown in Tables 3 to 5 and Figures 4 to 8 below.

division catalyst hydrogen
enter
(bar) reaction
temperature
(℃) Catalyst (production example) restoration
temperature
(℃) Pt:Ru:Sn
molar ratio Metal loading amount (wt.%) Total Pt Ru Sn Comparative Example 1 Pt/Al ₂ O ₃ (Comparative Manufacturing Example 1) 500 1:0:0 5.0 5.0 - - 50 270 Comparative example 2 Ru/Al ₂ O ₃ (Comparative Manufacturing Example 2) 500 0:1:0 5.0 - 5.0 - 50 270 Comparative Example 3 Sn/Al ₂ O ₃ (Comparative Manufacturing Example 3) 500 0:0:1 5.0 - - 5.0 50 270 Comparative example 4 Pt-Ru/Al ₂ O ₃ (Comparative Manufacturing Example 4) 500 1:1:0 5.0 3.3 1.7 - 50 270 Comparative Example 5 Ru-Sn/Al ₂ O ₃ (Comparative Manufacturing Example 5) 500 0:1:1 5.0 - 2.3 2.7 50 270 Comparative Example 6 Pt-Ru-Sn/Al ₂ O ₃ (Comparative Manufacturing Example 6) 500 1:1:1 5.0 2.4 1.2 1.4 50 270 Example 1 Pt-Sn/Al ₂ O ₃ (Production Example 9) 500 1:0:1.00 5.0 3.1 - 1.9 50 270 Example 2 Pt-Sn/Al ₂ O ₃ (Production Example 1) 500 1:0:0.33 5.0 4.2 - 0.8 50 270 Example 3 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 50 270 Example 4 Pt-Sn/Al ₂ O ₃ (Production Example 10) 500 1:0:2.00 5.0 2.3 - 2.7 50 270 Example 5 Pt-Sn/Al ₂ O ₃ (Production Example 2) 500 1:0:0.50 3.0 2.3 - 0.7 50 270 Example 6 Pt-Sn/Al ₂ O ₃ (Production Example 3) 500 1:0:0.50 4.0 3.1 - 0.9 50 270 Example 7 Pt-Sn/Al ₂ O ₃ (Production Example 5) 500 1:0:0.50 6.0 4.6 - 1.4 50 270 Example 8 Pt-Sn/Al ₂ O ₃ (Production Example 6) 500 1:0:0.33 6.0 5.0 - 1.0 50 270 Example 9 Pt-Sn/Al ₂ O ₃ (Production Example 7) 500 1:0:0.50 6.5 5.0 - 1.5 50 270 Example 10 Pt-Sn/Al ₂ O ₃ (Production Example 8) 500 1:0:1.00 8.0 5.0 - 3.0 50 270 Example 11 Pt-Sn/ZnTiO ₃ (Production Example 11) 500 1:0:0.50 5.0 3.8 - 1.2 50 270 Example 12 Pt-Sn/SiO ₂ (Production Example 12) 500 1:0:0.50 5.0 3.8 - 1.2 50 270 Example 13 Pt-Sn/Al ₂ O ₃ (Production Example 4) 400 1:0:0.50 5.0 3.8 - 1.2 50 270 Example 14 Pt-Sn/Al ₂ O ₃ (Production Example 4) 600 1:0:0.50 5.0 3.8 - 1.2 50 270 Example 15 Pt-Sn/Al ₂ O ₃ (Production Example 4) 700 1:0:0.50 5.0 3.8 - 1.2 50 270 Example 16 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 50 260 Example 17 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 50 280 Example 18 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 50 290 Example 19 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 50 300 Example 20 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 20 270 Example 21 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 30 270 Example 22 Pt-Sn/Al ₂ O ₃ (Production Example 4) 500 1:0:0.50 5.0 3.8 - 1.2 40 270

<PET conversion rate and BTX yield calculation results according to the type of active metal in the catalyst>

division Catalyst (production example) PET
Conversion rate (%) benzene
transference number(%) toluene
transference number(%) p-xylene
transference number(%) BTX
transference number(%) Comparative Example 1 Pt/Al ₂ O ₃
(Comparative Manufacturing Example 1) 45.2 0.02 0.03 0.25 0.30 Comparative example 2 Ru/Al ₂ O ₃
(Comparative Manufacturing Example 2) 37.5 0.04 0.03 0.01 0.08 Comparative Example 3 Sn/Al ₂ O ₃
(Comparative Manufacturing Example 3) 36.7 0.02 0.02 0.10 0.14 Comparative example 4 Pt-Ru/Al ₂ O ₃
(Comparative Manufacturing Example 4) 49.5 0.01 0.05 0.09 0.15 Comparative Example 5 Ru-Sn/Al ₂ O ₃
(Comparative Manufacturing Example 5) 35.8 0.04 0.03 0.00 0.07 Comparative Example 6 Pt-Ru-Sn/Al ₂ O ₃
(Comparative Manufacturing Example 6) 73.5 0.00 3.94 44.0 47.94 Example 1 Pt-Sn/Al ₂ O ₃
(Production Example 9) 99.8 0.44 2.55 68.2 71.19

Referring to Table 3 and Figure 4, Example 1 uses a catalyst containing Pt and Sn as the active metal, and Comparative Example 1 uses any one of Pt, Ru, and Sn as the active metal instead of the two active metals. Compared to Comparative Examples 4 to 5, which used Pt-Ru or Ru-Sn rather than Pt and Sn as the active bimetal of ~3 and the catalyst, the BTX yield was improved by at least 230 times, and the p-xylene yield was at least 270 times. It was found to have increased by more than twofold.

In addition, Example 1 using a two-metal catalyst had a BTX yield of 48% and a p-xylene yield of 55% compared to Comparative Example 6 using the catalyst of Comparative Preparation Example 6, which is a three-metal catalyst containing Ru in Pt and Sn. It was confirmed to be improved.

<PET conversion rate and BTX yield calculation results according to the molar ratio of Pt and Sn in the catalyst>

division catalyst hydrogen
enter
(bar) reaction
temperature
(℃) PET
conversion rate
(%) benzene
transference number
(%) toluene
transference number
(%) p-xylene
transference number
(%) BTX
transference number
(%) Catalyst (production example) Pt:Sn
molar ratio Example 2 Pt-Sn/Al ₂ O ₃
(Production Example 1) 1:0.33 50 270 99.3 0.69 5.30 59.30 65.29 Example 3 Pt-Sn/Al ₂ O ₃
(Production Example 4) 1:0.50 50 270 100 0.67 4.37 72.25 77.29 Example 4 Pt-Sn/Al ₂ O ₃
(Production Example 10) 1:2.00 50 270 92.2 0.69 1.32 61.25 63.26

Referring to Table 4 and Figure 5, it was confirmed that there is an optimal Pt:Sn molar ratio, and that the optimal molar ratio is 1:0.5.

<PtSn/Al ₂ O ₃ PET conversion rate and BTX yield calculation results according to the metal loading amount of Pt and Sn in the catalyst>

division catalyst PET
conversion rate
(%) benzene
transference number
(%) toluene
transference number
(%) p-xylene
transference number
(%) BTX
transference number
(%) Catalyst (production example) Pt:Sn
molar ratio Metal loading amount (wt.%) Total Pt Ru Sn Example 3 Pt-Sn/Al ₂ O ₃
(Production Example 4) 1:0.5 5.0 3.8 - 1.2 100 0.67 4.37 72.25 77.29 Example 5 Pt-Sn/Al ₂ O ₃
(Production Example 2) 1:0.5 3.0 2.3 - 0.7 90.3 0.40 3.85 58.67 62.92 Example 6 Pt-Sn/Al ₂ O ₃
(Production Example 3) 1:0.5 4.0 3.1 - 0.9 95.1 0.44 4.26 67.53 72.23 Example 7 Pt-Sn/Al ₂ O ₃
(Production Example 5) 1:0.5 6.0 4.6 - 1.4 99.6 0.39 5.54 70.13 76.06

Referring to Table 5 and Figure 6, it appears that the yield of BTX and p-xylene of the catalyst of Example 3 with a metal loading amount of Pt and Sn of 5 wt% is the best, indicating that there is an optimum point in the molar ratio of Pt:Sn. Could know.

<PET conversion rate and BTX yield calculation results according to the metal loading amount of Sn in a bimetallic catalyst with a fixed Pt content of 5 wt%>

division catalyst PET
conversion rate
(%) benzene
transference number
(%) toluene
transference number
(%) p-xylene
transference number
(%) BTX
transference number
(%) Catalyst (production example) Pt:Sn
molar ratio Metal loading amount (wt.%) Total Pt Ru Sn Example 8 Pt-Sn/Al ₂ O ₃
(Production Example 6) 1:0.33 6.0 5.0 - 1.0 99.0 0.54 1.10 56.94 58.58 Example 9 Pt-Sn/Al ₂ O ₃
(Production Example 7) 1:0.50 6.5 5.0 - 1.5 99.5 0.35 1.16 59.45 60.96 Example 10 Pt-Sn/Al ₂ O ₃
(Production Example 8) 1:1.00 8.0 5.0 - 3.0 99.4 0.23 1.36 62.77 64.36

Referring to Table 6, it can be seen that the BTX yield increases as the Sn content increases, and it was confirmed that Example 10 with a Pt/Sn content ratio of 1:1 had the highest p-xylene yield and BTX selectivity. .

<PET conversion rate and BTX yield calculation results according to catalyst support type>

division catalyst hydrogen
enter
(bar) reaction
temperature
(℃) PET
conversion rate
(%) benzene
transference number
(%) toluene
transference number
(%) p-xylene
transference number
(%) BTX
transference number
(%) Catalyst (production example) Pt:Sn
molar ratio Example 3 Pt-Sn/Al ₂ O ₃
(Production Example 1) 1:0.50 50 270 100 0.67 4.37 72.25 77.29 Example 11 Pt-Sn/ZnTiO ₃
(Production Example 11) 1:0.50 50 270 99.4 0.23 1.36 62.77 64.36 Example 12 Pt-Sn/ _SiO2
(Production Example 12) 1:0.50 50 270 95.5 0.07 0.30 25.9 26.27

Referring to Table 7, the BTX and p-xylene yields differed depending on the type of catalyst support, and were found to be highest in that order: alumina, zinc titanium composite metal oxide, and silica. In particular, the Preparation Example 4 catalyst using an alumina support was confirmed to have a 2.9-fold increase in BTX and p-xylene yield compared to the Preparation Example 12 catalyst using silica.

<PET conversion rate and BTX yield calculation results according to reaction time>

Figure 7 is a graph showing the PET conversion rate and BTX yield according to reaction time in the presence of the catalyst in Preparation Example 4 as an example of the present invention.

Referring to Figure 7, the PET conversion rate and the yield of p-xylene increase rapidly until the reaction time is 6 hours, but then the increase rate gradually decreases. The PET conversion rate is achieved at 100% during the reaction time of 12 to 30 hours, and p -It was confirmed that the xylene yield converged to about 70%.

<Yield calculation results of by-products according to reaction time>

Figure 8 is an example of the present invention, showing products other than BTX (a: alkyl aromatic and cycloaliphatic other than BTX, b: benzoate and terephthalate, c: dimer product) according to reaction time in the presence of catalyst in Preparation Example 4. ) This is a graph showing the yield.

Referring to Figure 8, it can be seen that EG present in PET is rapidly removed by the hydrogen decomposition reaction at the beginning of the PET decomposition reaction, and is produced by hydrogen decomposition (Hydrogenolysis) rather than a reaction by-product generated by decarboxylation. It was confirmed that more reaction by-products were produced.

<PET conversion rate and BTX yield calculation results according to catalyst reduction temperature>

division catalyst hydrogen
enter
(bar) reaction
temperature
(℃) PET
conversion rate
(%) benzene
transference number
(%) toluene
transference number
(%) p-xylene
transference number
(%) BTX
transference number
(%) Catalyst (production example) reduction temperature
(℃) Example 3 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 50 270 100 0.67 4.37 72.25 77.29 Example 13 Pt-Sn/Al ₂ O ₃
(Production Example 4) 400 50 270 99.7 0.35 3.20 68.08 71.63 Example 14 Pt-Sn/Al ₂ O ₃
(Production Example 4) 600 50 270 99.5 0.41 2.64 56.23 59.28 Example 15 Pt-Sn/Al ₂ O ₃
(Production Example 4) 700 50 270 99.4 0.29 2.56 53.85 56.70

Referring to Table 8, there is an optimum temperature for the reduction temperature of the catalyst, and the optimum temperature was found to be 500°C.

<PET conversion rate and BTX yield calculation results according to reaction temperature in the presence of catalyst>

division catalyst hydrogen
enter
(bar) reaction
temperature
(℃) PET
conversion rate
(%) benzene
transference number
(%) toluene
transference number
(%) p-xylene
transference number
(%) BTX
transference number
(%) Catalyst (production example) reduction temperature
(℃) Example 3 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 50 270 100 0.67 4.37 72.25 77.29 Example 16 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 50 260 93.5 0.35 2.00 61.74 64.09 Example 17 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 50 280 100 0.96 6.88 75.4 83.24 Example 18 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 50 290 100 2.26 8.49 77.09 87.84 Example 19 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 50 300 100 1.69 9.65 71.25 82.59

Referring to Table 9, it was found that there was an optimal temperature for the hydrogenation cracking reaction in the presence of the same catalyst in Preparation Example 4, and the optimal temperature was found to be 290°C.

<PET conversion rate and BTX yield calculation results according to hydrogen pressure>

division catalyst hydrogen
enter
(bar) reaction
temperature
(℃) PET
conversion rate
(%) benzene
transference number
(%) toluene
transference number
(%) p-xylene
transference number
(%) BTX
transference number
(%) Catalyst (production example) reduction temperature
(℃) Example 3 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 50 270 100 0.67 4.37 72.25 77.29 Example 20 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 20 270 59.8 0.03 0.32 7.43 7.78 Example 21 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 30 270 82.2 0.26 3.62 37.25 41.13 Example 22 Pt-Sn/Al ₂ O ₃
(Production Example 4) 500 40 270 90.3 0.26 3.48 54.15 57.89

Referring to Table 10, it was found that the yields of BTX and p-xylene improved as the hydrogen pressure introduced into the hydrocracking reaction in the presence of the same catalyst in Preparation Example 4 increased from 20 bar to 50 bar.

Above, the present invention has been described with reference to the embodiments described in the specification or shown in the accompanying drawings, but these are merely illustrative, and various modifications and equivalents can be made by those skilled in the art. It will be appreciated that other embodiments are possible. Therefore, the scope of technical protection of the present invention should be determined by the scope of the patent claims below.

Claims (10)

A bimetallic catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group, characterized in that it contains Pt and Sn as active metals.
According to paragraph 1,
A two-metal catalyst for the decomposition reaction of an aromatic polymer containing an ester functional group, wherein the active metal is supported on an acidic support.
According to paragraph 1,
A bimetallic catalyst for aromatic polymer decomposition reaction containing an ester functional group, wherein the molar ratio of Pt:Sn is 1:0.05 to 1:3.0.
According to paragraph 2,
A bimetallic catalyst for aromatic polymer decomposition reaction containing an ester functional group, characterized in that the amount of active metal supported in the catalyst is 1.0 to 20 wt% based on the total weight of the catalyst.
According to paragraph 1,
The catalyst is a bimetallic catalyst for aromatic polymer decomposition reaction containing an ester functional group, characterized in that the catalyst is calcined at a temperature in the range of 200 to 800 ° C.
(A) reducing the bimetallic catalyst for aromatic polymer decomposition reaction containing the ester functional group of any one of claims 1 to 5;
(B) performing a decomposition reaction by contacting the reduced catalyst of step (A) with an aromatic polymer containing an ester functional group; and
(C) obtaining an alkylaromatic hydrocarbon from the decomposition reaction of the aromatic polymer containing an ester functional group in step (B); method.
According to clause 6,
A method for selectively producing an alkyl aromatic hydrocarbon from an aromatic polymer containing an ester functional group, characterized in that the reduction temperature of the catalyst in step (A) is in the range of 200 to 800 ° C.
According to clause 6,
In the step (B), the decomposition reaction of the aromatic polymer containing an ester functional group is characterized in that it includes a hydrogenation decomposition reaction and a hydrogenation deoxygenation reaction. method.
According to clause 6,
A method for producing alkyl aromatic hydrocarbons with high yield and high selectivity from an aromatic polymer containing an ester functional group, characterized in that the decomposition reaction of the aromatic polymer containing an ester functional group in step (B) is carried out in the range of 200 to 350 ° C. .
According to clause 6,
The decomposition reaction of the aromatic polymer containing an ester functional group in step (B) is performed at a hydrogen pressure range of 10 to 300 bar, and produces an alkyl aromatic hydrocarbon in high yield and high selectivity from an aromatic polymer containing an ester functional group. How to.