Performance of Bifunctional ZnZr/ZSM-5 Catalysts in the Alkylation of Benzene with Syngas

Bai, Youhuang; Yang, Fan; Liu, Xiangyu; Liu, Chenxu; Zhu, Xuedong

doi:10.1007/s10562-018-2570-6

Cited by 20 publications

(17 citation statements)

References 38 publications

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“…We have also carried out the one-pot methylation of naphthalene over Re(1)/TiO 2 and H-β (SiO 2 /Al 2 O 3 = 40). Compared to the methylation of arenes using syngas (that is, a CO/H 2 mixture), − this process, which directly uses CO 2 , would be beneficial. In addition, our process shows greater productivity of methylated products than the methylation process using methane as a carbon source .…”

Section: Introductionmentioning

confidence: 99%

Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO₂ and H₂ over TiO₂-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

et al. 2021

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Catalytic methylation of aromatic hydrocarbons using CO2 and H2 as a methylating agent was conducted over a combination of TiO2-supported Re (Re(1)/TiO2; Re = 1 wt %) and H-β (SiO2/Al2O3 = 40) in a batch reactor. Catalytic methylation of m-xylene was performed, and this catalyst combination demonstrated excellent performance for the synthesis of methylbenzenes, giving a high yield of total methylated products (10 and 57%, as calculated on the basis of CO2 and m-xylene, respectively), while generating relatively small amounts of byproducts such as demethylated and dearomatized products as well as CO and CH4 in the gas phase under the investigated reaction conditions (p CO2 = 1 MPa, p H2 = 5 MPa, T = 240 °C, t = 20 h). Our catalysts were also found to perform well for the methylation of toluene, providing a high yield and high selectivity for methylated products compared with the other investigated catalyst combinations. In addition to conducting conventional-type catalyst research, we used a data science approach based on machine learning techniques to identify important input variables that govern the catalytic performance, enabling optimization of the catalyst for the methylation reaction. Compared with the catalysts optimized using the conventional approach, the improved Re/TiO2 catalyst with a Re loading amount of 1.8 wt %, which was optimized with the aid of ML, exhibited greater activity toward the methylation of benzene using CO2/H2.

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Section: Introductionmentioning

confidence: 99%

Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO₂ and H₂ over TiO₂-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

et al. 2021

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“…Based on the above experimental results and relevant literature records, we speculated that the reaction mechanism of the alkylation of benzene and syngas in the bifunctional catalyst is shown in Figure . The bifunctional catalyst carried out a two-step reaction by two active sites, so the reaction is made up of two steps: the first is the reaction of syngas on the ZrO 2 catalyst to form intermediate methanol; and the second is further divided into two routes, one of which is the alkylation reaction between methanol and raw benzene (route 1) and the other is the direct aromatization of methanol to form aromatics (route 2). , In route 1, methanol was dehydrated to form dimethyl ether, and the resulting dimethyl ether and the undehydrated methanol combined with the Brønsted acid sites of the zeolite to form methanol carbocation, which attacked the benzene molecule and obtained protonated toluene. When the protonated toluene returned the proton to the zeolite, toluene was formed.…”

Section: Results and Discussionmentioning

confidence: 99%

Dual Effects of Zinc Species on Active Sites in Bifunctional Composite Catalysts Zr/H[Zn]ZSM-5 for Alkylation of Benzene with Syngas

Ding

Wang

et al. 2019

J. Phys. Chem. C

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Bifunctional composite catalysts Zr/H[Zn] x Z with different Zn contents were prepared by combining the impregnation and physical mixing method. The effect of zinc species on two active sites in bifunctional composite catalysts Zr/H[Zn]ZSM-5 for alkylation of benzene with syngas has been investigated. The results indicated that the introduction of Zn greatly improves the catalytic performance and the selectivity of target products and changed with the change of Zn content. The sample Zr/H[Zn]3Z exhibited the highest total selectivity of toluene and xylene of 91% and the benzene conversion of 18% at 400 °C under 3.3 MPa; nevertheless, the sample Zr/H[Zn]5Z showed the highest benzene conversion and xylene selectivity, which reached 31 and 27%, respectively. The acidic properties and state of Zn species of H[Zn] x Z zeolites have also been explored. All evidence suggested that most of Zn introduced into HZ zeolite existed in the catalyst as Zn(OH)+, forming new Zn-Lewis acid at the expense of Brønsted acid. The Zn species plays a role in three aspects in the alkylation reaction between benzene and syngas. First, the Zn species can provide H species for ZrO2 activation of CO by promoting H2 activation, thus generating more methanol; second, Zn(OH)+ species formed in zeolite can inhibit the side reactions of methanol so as to promote the alkylation of benzene and methanol; finally, the Zn-Lewis acidic sites can inhibit the cracking reaction of C6+ olefins and further promote the dehydrogenation aromatization reaction.

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“…Catalyst screening using various combinations of supported metal catalysts and zeolites having a wide range of SiO 2 /Al 2 O 3 ratios showed that this combination provided the best performance for the methylation reaction. Although the methylation of arenes, including benzene, using syngas (that is, CO/H 2 ) has been reported, the direct use of CO 2 would be beneficial. In addition, while the direct synthesis of aromatic hydrocarbons, including methylated benzenes, from CO 2 /H 2 mixtures that do not contain benzene has been realized, these processes typically require harsh conditions .…”

Section: Figurementioning

confidence: 99%

Catalytic Methylation of Aromatic Hydrocarbons using CO₂/H₂ over Re/TiO₂ and H‐MOR Catalysts

et al. 2020

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A combined catalyst comprising TiO 2 -supported Re (Re(1)/TiO 2 ; Re = 1 wt%) and H-MOR (SiO 2 /Al 2 O 3 = 90) was found to promote the methylation of benzene using CO 2 and H 2 . This catalytic system exhibited high performance with regard to the synthesis of methylated benzenes and gave high yields of total methylated products (up to 52 % benzene-based yield and 42 % CO 2based yield) under the reaction conditions employed in this study (p CO2 = 1 MPa; p H2 = 5 MPa; T = 250°C; t = 20 h) in a batch reactor. Catalyst screening demonstrated that a combination of Re(1)/TiO 2 and H-MOR (SiO 2 /Al 2 O 3 = 90) exhibited superior performance compared to other combinations of supported metal catalysts and zeolites in terms of both yield and selectivity for methylated benzenes.

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Performance of Bifunctional ZnZr/ZSM-5 Catalysts in the Alkylation of Benzene with Syngas

Cited by 20 publications

References 38 publications

Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO₂ and H₂ over TiO₂-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO₂ and H₂ over TiO₂-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

Dual Effects of Zinc Species on Active Sites in Bifunctional Composite Catalysts Zr/H[Zn]ZSM-5 for Alkylation of Benzene with Syngas

Catalytic Methylation of Aromatic Hydrocarbons using CO₂/H₂ over Re/TiO₂ and H‐MOR Catalysts

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Performance of Bifunctional ZnZr/ZSM-5 Catalysts in the Alkylation of Benzene with Syngas

Cited by 20 publications

References 38 publications

Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO2 and H2 over TiO2-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO2 and H2 over TiO2-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

Dual Effects of Zinc Species on Active Sites in Bifunctional Composite Catalysts Zr/H[Zn]ZSM-5 for Alkylation of Benzene with Syngas

Catalytic Methylation of Aromatic Hydrocarbons using CO2/H2 over Re/TiO2 and H‐MOR Catalysts

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Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO₂ and H₂ over TiO₂-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

Catalytic Methylation of m-Xylene, Toluene, and Benzene Using CO₂ and H₂ over TiO₂-Supported Re and Zeolite Catalysts: Machine-Learning-Assisted Catalyst Optimization

Catalytic Methylation of Aromatic Hydrocarbons using CO₂/H₂ over Re/TiO₂ and H‐MOR Catalysts