A catalyst for preparing symmetrical octahydroanthracene by selective hydrogenation and ring-migration of phenanthrene in one step

Abstract

The application discloses a catalyst applied to a one-step method for selectively hydrogenating and ring-shifting phenanthrene to prepare symmetrical octahydroanthracene, and belongs to the fields of coal chemical industry and fine chemical industry; based on the wide industrial application range and considerable economic added value of symmetrical octahydroanthracene, a zeolite-supported noble metal bifunctional catalyst is innovatively used to design a reasonable chemical route for controllable synthesis of high-added-value symmetrical octahydroanthracene by taking phenanthrene as a raw material; under relatively mild reaction conditions, the conversion of phenanthrene and the yield of symmetrical octahydroanthracene are effectively improved. The catalyst used in the application has the advantages of simple preparation method, strong adjustability and low cost, and the reaction condition is relatively mild. Meanwhile, the upgrading route of the application can not only simplify the complex process of a traditional production process and reduce the separation and purification cost, but also can fully utilize the characteristics that aromatic hydrocarbon compounds are rich in coal tar, exert the potential value of the coal tar, and promote the high-value utilization of the coal tar.

Description

Technical Field

[0001] This invention belongs to the fields of coal chemical industry and fine chemical industry, and specifically relates to a catalyst for the one-step preparation of symmetrical octahydroanthracene by selective hydrogenation cyclotransfer isomerization of phenanthrene. Background Technology

[0002] Anthracene and phenanthrene are the main tricyclic components in high-temperature coal tar. Symmetric octahydroanthracene (sym-OHA), a selective hydrogenation product of anthracene, not only has a wide range of industrial applications as a dye, functional molecule intermediate, and pharmaceutical intermediate, but also possesses significant economic value. While phenanthrene content in high-temperature coal tar is approximately four times that of anthracene, the industrial applications of phenanthrene and its derivatives are limited. Therefore, how to convert phenanthrene into high-value-added products is a crucial issue that urgently needs to be addressed to improve the comprehensive utilization value of coal tar. Currently, the main approach to upgrading and modifying high-temperature coal tar focuses on hydrogenation to produce fuel oil. However, this conversion route not only consumes a large amount of hydrogen and requires harsh reaction conditions, resulting in high production costs, but also fails to fully utilize the structural characteristics of the components contained in coal tar, leading to a waste of coal tar resources. Based on the wide range of industrial applications and considerable economic value of symmetric octahydroanthracene, this invention proposes a promising and attractive upgrade route: selectively hydrogenating phenanthrene to symmetric octahydroanthracene and then isomerizing it into the high-value-added symmetric octahydroanthracene. This transformation and upgrading method can make full use of the characteristic of coal tar being rich in aromatic compounds, give full play to the potential value of coal tar, and promote the high-value utilization of coal tar.

[0003] The key to realizing this high-value conversion route lies in the preparation of highly efficient catalysts. Traditional metal sulfide catalysts have been widely used for the hydrogenation of polycyclic aromatic hydrocarbons (PAHs), especially phenanthrene. However, the reaction conditions are usually high temperature and high pressure, and the reaction is easily limited by thermodynamic equilibrium, which greatly restricts the hydrogenation capacity of phenanthrene. In addition, existing hydrogenation catalysts are mainly used for the selective hydrogenation of anthracene to symmetric octahydroanthracene and the saturation of PAHs in oil products and coal tar, but do not involve the highly selective direct conversion of phenanthrene to symmetric octahydroanthracene. The conversion of phenanthrene, the main component of coal-based feedstock, to symmetric octahydroanthracene involves not only selective hydrogenation but also ring shift isomerization, but there are very few studies on such catalysts in the currently published literature. Therefore, it is essential to develop highly efficient catalysts that can directionally convert phenanthrene into high-value-added symmetric octahydroanthracene. Summary of the Invention

[0004] In view of the above, the purpose of this invention is to provide a catalyst for the one-step preparation of symmetrical octahydroanthracene using selective hydrogenation cyclization isomerization of phenanthrene. This is mainly to address the shortcomings of current hydrogenation and upgrading methods for polycyclic aromatic hydrocarbons (PAHs), the main components of high-temperature coal tar, which suffer from high hydrogen consumption, harsh reaction conditions, high production costs, and inability to fully utilize the structural characteristics and high-value utilization of coal tar components, as well as the high cost of separating and purifying intermediate products.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A catalyst for the one-step preparation of symmetrical octahydroanthracene via selective hydrogenation cyclization isomerization of phenanthrene is provided. The given symmetrical octahydroanthracene catalyst is a bifunctional catalyst supported on HBeta zeolite with different silica-to-alumina ratios and containing a platinum (Pt) noble metal component, denoted as Pt / HBeta catalyst. In the Pt / HBeta catalyst, the support is pretreated HBeta zeolite, and the active component is Pt. Based on mass percentage, the noble metal is either a chloride or an ammonia complex, wherein the loading of Pt is 0.3-1.0 wt%.

[0006] The HBeta zeolite refers to zeolite obtained by exchanging sodium ions in the Beta molecular sieve for hydrogen ions using ion exchange. HBeta zeolite possesses a three-dimensional twelve-membered ring cross-channel structure, suitable pore size, good thermal and hydrothermal stability, and controllable acidity, making it suitable for a wide range of applications. The silica-alumina ratio of the HBeta carrier is 23-200.

[0007] The specific steps for the symmetrical octahydroanthracene catalyst are as follows:

[0008] 1) Preparation of supported noble metal catalysts by conventional impregnation method: Precursor noble metal salts are dispersed in deionized water, and then the support is placed in the above dispersion. During this process, the catalyst is continuously stirred in a constant temperature water bath to ensure that the active components are uniformly loaded onto the supports with different silicon-to-aluminum ratios. Subsequently, the solvent is removed, and the prepared catalyst is dried, calcined, and reduced.

[0009] 2) Noble metal catalysts with different loadings were prepared by conventional impregnation method, and the prepared catalysts were dried, calcined and reduced.

[0010] The calcination and reduction temperatures of the precious metal catalyst are 300-400 ℃.

[0011] The catalyst is used in the one-step process of selective hydrogenation cyclization isomerization of phenanthrene to produce symmetrical octahydroanthracene. Phenanthrene is dissolved in an organic solvent, and the resulting solution and catalyst are then placed in a high-pressure autoclave reactor for hydrogenation reaction. The reaction pressure is 2-4 MPa and the reaction temperature is 200-300 °C.

[0012] The organic solvent is one of cyclohexane, tetrahydrofuran, and decahydronaphthalene.

[0013] The one-step method for the selective hydrogenation and ring shift isomerization of phenanthrene to prepare symmetrical octahydroanthracene involves the selective hydrogenation of phenanthrene to symmetrical octahydrophenanthrene, followed by the conversion of symmetrical octahydrophenanthrene (ring-opening, alkyl chain isomerization, and ring-closure) to symmetrical octahydroanthracene. Furthermore, the one-step preparation of symmetrical octahydroanthracene involves coupling the two sequential reactions of selective hydrogenation of phenanthrene to symmetrical octahydrophenanthrene and the conversion of symmetrical octahydrophenanthrene (ring-opening, alkyl chain isomerization, and ring-closure) into a one-pot reaction (i.e., the same reactor) or a one-step reaction (i.e., the same reactor and reaction conditions).

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: First, based on the wide industrial application range and considerable economic added value of symmetrical octahydroanthracene, the innovative use of zeolite-supported noble metal catalysts successfully achieves a one-step controllable synthesis of high-value-added symmetrical octahydroanthracene using a rationally designed chemical route with phenanthrene, the main component of coal tar, as raw material. This simplifies the complex separation process to the greatest extent, reduces the purification cost of the target product, and fully utilizes the characteristic of coal tar being rich in aromatic compounds, thereby maximizing the potential value of coal tar and promoting its high-value utilization. Second, the provided zeolite-supported noble metal bifunctional catalyst has active centers capable of selectively hydrogenating polycyclic aromatic hydrocarbons and directional isomerization of selectively hydrogenated products. Under relatively mild reaction conditions, this catalyst exhibits suitable activity, effectively reducing the occurrence of cracking and excessive hydrogenation side reactions while increasing the yield of ring-isomer products. This enables a one-step upgrade of phenanthrene selective hydrogenation (symmetrical octahydrophenanthrene) to high-value-added symmetrical octahydroanthracene, effectively ensuring the conversion rate of phenanthrene and the yield of symmetrical octahydroanthracene. Attached Figure Description

[0015] Figure 1 This is the XRD pattern of the catalyst. Implementation

[0016] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only for a more comprehensive description of the present invention to facilitate understanding by those skilled in the art, but should not be construed as limiting the scope of the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0017] The symmetrical octahydroanthracene catalyst provided in this invention is prepared by the following specific method:

[0018] 1) Preparation of supported noble metal catalysts by conventional impregnation method: The precursor noble metal salt is dispersed in deionized water, and then the support is placed in the above dispersion. During this process, the catalyst is continuously stirred in a constant temperature water bath to ensure that the active components are uniformly loaded on the supports with different silicon-to-aluminum ratios. Subsequently, the solvent is removed, and the prepared catalyst is dried, calcined, and reduced.

[0019] 2) Noble metal catalysts with different loadings were prepared by conventional impregnation method, and the prepared catalysts were dried, calcined and reduced.

[0020] like Figure 1 As shown, the prepared catalyst is a bifunctional catalyst supported on HBeta zeolite with a silica-to-alumina ratio of 23-200 and containing a platinum (Pt) noble metal component. It is referred to as the Pt / HBeta catalyst. The support in the Pt / HBeta catalyst is pretreated HBeta zeolite, and the active component is Pt. Based on the mass percentage, the loading of Pt is 0.3-1.0 wt%. Example 1

[0021] Selective hydrogenation cyclization isomerization of phenanthrene was tested in a high-pressure autoclave reactor using Pt / HBeta-23. The reaction conditions were as follows: reaction temperature 250 °C, reaction pressure 3.0 MPaH2, catalyst / reactant ratio 0.5, solvent cyclohexane, reaction time 2 h. After cooling, the catalyst was separated, and the product was analyzed by chromatography-mass spectrometry. The conversion rate was 100%, and the selectivity for symmetric octahydroanthracene was 39.4%. Example 2

[0022] Selective hydrogenation cyclization isomerization of phenanthrene was tested in a Pt / HBeta-32 autoclave reactor. The reaction conditions were as follows: reaction temperature 250 °C, reaction pressure 3.0 MPaH2, catalyst / reactant ratio 0.5, solvent cyclohexane, reaction time 2 h. After cooling, the catalyst was separated, and the product was analyzed by chromatography-mass spectrometry. The conversion rate was 91.2%, the selectivity for symmetric octahydroanthracene was 33.2%, and the primary hydrogenation products dihydrophenanthrene and a small amount of tetrahydrophenanthrene were detected. Example 3

[0023] Selective hydrogenation cyclization isomerization of phenanthrene was tested in a Pt / HBeta-200 autoclave reactor. The reaction conditions were as follows: reaction temperature 250 °C, reaction pressure 3.0 MPaH2, catalyst / reactant ratio 0.5, solvent cyclohexane, reaction time 4 h. After cooling, the catalyst was separated, and the product was analyzed by chromatography-mass spectrometry. The conversion rate was 67.9%, the selectivity for symmetric octahydroanthracene was 11.2%, and the major product was dihydrophenanthrene.

[0024] Comparative Example 1

[0025] Selective hydrogenation cyclization isomerization of phenanthrene in Pt / Al₂O₃ was tested in a high-pressure autoclave reactor. The reaction conditions were as follows: reaction temperature 250 °C, reaction pressure 3.0 MPaH₂, catalyst / reactant ratio 0.5, solvent cyclohexane, reaction time 2 h. After cooling, the catalyst was separated, and the product was analyzed by chromatography-mass spectrometry. Symmetrical octahydroanthracene was not detected in the product.

[0026] Comparative Example 2

[0027] Selective hydrogenation cyclization isomerization of phenanthrene was performed on Pt / SiO2 in a high-pressure autoclave reactor. The reaction conditions were as follows: reaction temperature 250 °C, reaction pressure 3.0 MPaH2, catalyst / reactant ratio 0.5, solvent cyclohexane, reaction time 2 h. After cooling, the catalyst was separated, and the product was analyzed by chromatography-mass spectrometry. Symmetrical octahydroanthracene was not detected in the product.

[0028] Comparative Example 3

[0029] Selective hydrogenation cyclization isomerization of phenanthrene was performed on Pt / Al-MCM-41 in a high-pressure autoclave reactor. The reaction conditions were as follows: reaction temperature 250 °C, reaction pressure 3.0 MPaH2, catalyst / reactant ratio 0.5, solvent cyclohexane, reaction time 2 h. After cooling, the catalyst was separated, and the product was analyzed by chromatography-mass spectrometry. Symmetrical octahydroanthracene was not detected in the product.

[0030] Comparative Example 4

[0031] Selective hydrogenation cyclization isomerization of phenanthrene was tested in a high-pressure autoclave reactor using Pt / HZSM-5. The reaction conditions were as follows: reaction temperature 250 °C, reaction pressure 3.0 MPaH2, catalyst / reactant ratio 0.5, solvent cyclohexane, reaction time 4 h. After cooling, the catalyst was separated, and the product was analyzed by chromatography-mass spectrometry. Symmetrical octahydroanthracene was not detected in the product.

[0032] In summary, the proposed zeolite-supported noble metal bifunctional catalyst possesses active centers capable of selective hydrogenation of polycyclic aromatic hydrocarbons (PAHs) and directional isomerization of the selectively hydrogenated products. Under relatively mild reaction conditions, this catalyst exhibits suitable activity, effectively reducing cracking and over-hydrogenation side reactions while increasing the yield of cyclic isomerization products. This enables a one-step process to upgrade phenanthrene selective hydrogenation (symmetric octahydrophenanthrene) to high-value-added symmetric octahydroanthracene via cyclic isomerization, effectively ensuring both phenanthrene conversion and symmetric octahydroanthracene yield.

Claims

1. An application of a zeolite-supported noble metal bifunctional catalyst, Pt / HBeta, for the one-step preparation of symmetric octahydroanthracene via phenanthrene-selective hydrogenation cyclization isomerization, characterized in that: The Pt / HBeta catalyst is supported by pretreated HBeta zeolite, and the active component is Pt; based on mass percentage, the loading of Pt in the Pt / HBeta catalyst is 0.3-1.0 wt%. The HBeta zeolite refers to the HBeta zeolite obtained by exchanging the sodium ions of the Beta molecular sieve itself for hydrogen ions through ion exchange. The silica-alumina ratio of the carrier HBeta zeolite is 23-200.

2. The application according to claim 1, characterized in that: The HBeta zeolite has a three-dimensional twelve-membered ring cross-channel structure, suitable pore size, good thermal and hydrothermal stability, and controllable acidity.

3. The application according to claim 1, characterized in that: The Pt / HBeta catalyst was used in the one-step process of selective hydrogenation cyclization isomerization of phenanthrene to prepare symmetrical octahydroanthracene. Phenanthrene was dissolved in an organic solvent, and the resulting solution and catalyst were then placed in a high-pressure autoclave reactor for hydrogenation. The reaction pressure was 2-4 MPa and the reaction temperature was 200-300 °C. The one-step process of selective hydrogenation cyclization isomerization of phenanthrene to prepare symmetrical octahydroanthracene is a two-step sequential reaction of selective hydrogenation of phenanthrene to symmetrical octahydrophenanthrene and conversion of symmetrical octahydrophenanthrene to symmetrical octahydroanthracene coupled into a one-step reaction.

4. The application according to claim 3, characterized in that: The organic solvent is one of cyclohexane, tetrahydrofuran, and decahydronaphthalene.

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