Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol
The methanol–toluene alkylation process over zeolites catalysts offers a promising route for the production of <i>p</i>-xylene from low-cost feedstocks. Herein, we present a catalyst by preparing a core-shell aluminosilicate zeolite with an epitaxial silicalite-1 shell that passivates ac...
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MDPI AG
2022-11-01
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| author | Xu Pan Xin Huang Ruizhuang Wang Haiyong Zhang Hui Wei Jingyun Chen Suyao Liu Liping Sun Deping Xu Yi Liu |
| author_facet | Xu Pan Xin Huang Ruizhuang Wang Haiyong Zhang Hui Wei Jingyun Chen Suyao Liu Liping Sun Deping Xu Yi Liu |
| author_sort | Xu Pan |
| collection | DOAJ |
| description | The methanol–toluene alkylation process over zeolites catalysts offers a promising route for the production of <i>p</i>-xylene from low-cost feedstocks. Herein, we present a catalyst by preparing a core-shell aluminosilicate zeolite with an epitaxial silicalite-1 shell that passivates acid sites on the exterior surfaces. The <i>para</i>-selectivity was obviously increased due to the inhibition of the unselective isomerization of <i>p</i>-xylene over the external acid sites, and the open porous structure of the silicalite-1 shell ensured the mass transfer of reactants and products. Meanwhile, the carbon deposition was suppressed over HZSM-5@silicalite-1 catalysts, as a result of the decreased external acid sites. Furthermore, pulse chromatographic experiments revealed that the silicalite-1 coating could also improve the separation efficiency of <i>p</i>-xylene over <i>o</i>-xylene and <i>m</i>-xylene, due to the steric hindrance and extended diffusion path, resulting in a higher selectivity for <i>p</i>-xylene compared to that of the parent HZSM-5. The HZSM-5@4%S-1 catalyst showed the highest <i>p</i>-xylene selectivity (>80%) and methanol efficiency (66%), with good catalytic stability throughout the 170 h reaction time. |
| first_indexed | 2024-03-09T17:13:08Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2073-4344 |
| language | English |
| last_indexed | 2024-03-09T17:13:08Z |
| publishDate | 2022-11-01 |
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| record_format | Article |
| series | Catalysts |
| spelling | doaj.art-2a9726993af442e5ac757f16984ceaed2023-11-24T13:50:40ZengMDPI AGCatalysts2073-43442022-11-011212153810.3390/catal12121538Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with MethanolXu Pan0Xin Huang1Ruizhuang Wang2Haiyong Zhang3Hui Wei4Jingyun Chen5Suyao Liu6Liping Sun7Deping Xu8Yi Liu9School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083, ChinaNational Institute of Clean-and-Low-Carbon Energy (NICE), Beijing 102211, ChinaNational Institute of Clean-and-Low-Carbon Energy (NICE), Beijing 102211, ChinaSchool of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083, ChinaNational Institute of Clean-and-Low-Carbon Energy (NICE), Beijing 102211, ChinaNational Institute of Clean-and-Low-Carbon Energy (NICE), Beijing 102211, ChinaNational Institute of Clean-and-Low-Carbon Energy (NICE), Beijing 102211, ChinaChina Energy Technology and Economics Research Institute, China Energy Investment Corporation Ltd., Beijing 100011, ChinaSchool of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083, ChinaNational Institute of Clean-and-Low-Carbon Energy (NICE), Beijing 102211, ChinaThe methanol–toluene alkylation process over zeolites catalysts offers a promising route for the production of <i>p</i>-xylene from low-cost feedstocks. Herein, we present a catalyst by preparing a core-shell aluminosilicate zeolite with an epitaxial silicalite-1 shell that passivates acid sites on the exterior surfaces. The <i>para</i>-selectivity was obviously increased due to the inhibition of the unselective isomerization of <i>p</i>-xylene over the external acid sites, and the open porous structure of the silicalite-1 shell ensured the mass transfer of reactants and products. Meanwhile, the carbon deposition was suppressed over HZSM-5@silicalite-1 catalysts, as a result of the decreased external acid sites. Furthermore, pulse chromatographic experiments revealed that the silicalite-1 coating could also improve the separation efficiency of <i>p</i>-xylene over <i>o</i>-xylene and <i>m</i>-xylene, due to the steric hindrance and extended diffusion path, resulting in a higher selectivity for <i>p</i>-xylene compared to that of the parent HZSM-5. The HZSM-5@4%S-1 catalyst showed the highest <i>p</i>-xylene selectivity (>80%) and methanol efficiency (66%), with good catalytic stability throughout the 170 h reaction time.https://www.mdpi.com/2073-4344/12/12/1538heterogeneous catalysismethanol toluene alkylationHZSM-5silicalite-1<i>para</i>-xylene |
| spellingShingle | Xu Pan Xin Huang Ruizhuang Wang Haiyong Zhang Hui Wei Jingyun Chen Suyao Liu Liping Sun Deping Xu Yi Liu Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol Catalysts heterogeneous catalysis methanol toluene alkylation HZSM-5 silicalite-1 <i>para</i>-xylene |
| title | Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol |
| title_full | Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol |
| title_fullStr | Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol |
| title_full_unstemmed | Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol |
| title_short | Effects of Silicalite-1 Coating on the <i>p</i>-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol |
| title_sort | effects of silicalite 1 coating on the i p i xylene selectivity and catalytic stability of hzsm 5 in toluene methylation with methanol |
| topic | heterogeneous catalysis methanol toluene alkylation HZSM-5 silicalite-1 <i>para</i>-xylene |
| url | https://www.mdpi.com/2073-4344/12/12/1538 |
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