Article
Chemistry, Physical
Antoine Beuque, Matthias Barreau, Elise Berrier, Jean-Francois Paul, Nuno Batalha, Alexander Sachse, Ludovic Pinard
Summary: The study on ethylene dehydroaromatisation revealed that the presence of long diffusion path lengths in micro-sized zeolite leads to mass transfer resistance, while nano-sized zeolite promotes fast formation of the active hydrocarbon pool due to shorter diffusion path length, resulting in higher activity and selectivity into benzene with significantly mitigated catalyst deactivation.
Article
Chemistry, Physical
Aurelien Bonnin, Yannick Pouilloux, Vincent Coupard, Denis Uzio, Ludovic Pinard
Summary: This study aims to identify the deactivation mechanism(s) in the aromatization of dilute ethylene on Zn/H-MFI catalyst, revealing that deactivation is mainly caused by coke deposition rather than Zn sublimation. The balance between Lewis and Bronsted acid sites plays a significant role in predicting catalyst stability, and the reduction of micropore volume serves as the best descriptor for deactivation.
APPLIED CATALYSIS A-GENERAL
(2021)
Article
Energy & Fuels
Yingkai Li, Nishu, Dominic Yellezuome, Chong Li, Ronghou Liu
Summary: This study evaluated the deactivation process and regeneration effects of bimetallic Fe-Ni/ZSM-5 catalysts in the catalytic pyrolysis of poplar sawdust. The results showed that the deoxygenation activity and hydrocarbon yield of the catalyst were influenced by the biomass/catalyst ratio. The coke resistance capacity of the catalyst was increased, and the regenerated catalyst retained deoxygenation activity with slightly reduced aromatic yield.
Article
Chemistry, Applied
Xiang Gao, Ling Zhang, Zhichao Tao, Huimin Chen, Yu Zhang, Huiyong Gong, Xiaodong Wen, Yong Yang, Yongwang Li
Summary: This study prepared three ZSM-5 samples (Z-0.1, Z-1.5 and Z-5.0) using different amounts of Silicalite-1 seed, and modified them with Zn impregnation method. The addition of seeds affected the particle size, mesopore volume, acidity and crystal surface of resulting zeolites, influencing their catalytic performance on propane aromatization. Zn impregnation improved the catalytic stability of the samples, with Z-5.0 showing the best distribution of Zn and highest BTX selectivity.
Article
Chemistry, Physical
Jonas Hedlund, Ming Zhou, Abrar Faisal, Olov G. W. Oehrman, Valeria Finelli, Matteo Signorile, Valentina Crocella, Mattias Grahn
Summary: In this study, a systematic investigation was conducted on two sets of defect-free and defective ZSM-5 crystals with controlled thickness. Their performances in methanol conversion were analyzed, and strong correlations were observed between crystal thickness and deactivation rate as well as selectivity. Thinner defect-free crystals showed superior activity and selectivity, while thicker crystals and crystals with defects exhibited faster deactivation.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Runze Jin, Haobin Hu, Jiaofei Wang, Zhuangzhuang Zhang, Chengyi Dai, Xiaoxun Ma
Summary: Dividing the traditional methanol to aromatics reaction into two steps using SAPO-34 and Zn/ZSM-5 as catalysts can significantly improve the aromatic selectivity through optimized loading methods and ratios.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Physical
Gabriel L. Catuzo, Luiz G. Possato, Maria Eugenia Sad, Cristina Padro, Leandro Martins
Summary: This study investigates the detailed aging of coke in spent H-ZSM-5 zeolites after their use in the gas-phase glycerol dehydration to produce acrolein. The carbonaceous deposits formed rapidly in the pores hampering the accessibility to active sites and the zeolite's catalytic action. The types of coke formed during the reaction and their impact on the zeolite's structure and accessibility to acid sites were also examined.
Article
Thermodynamics
Bruno J. B. Silva, Lenivaldo V. Sousa, Lais R. A. Sarmento, Ana C. S. Melo, Deidiane S. Silva, Paulo H. L. Quintela, Soraya L. Alencar, Antonio O. S. Silva
Summary: The study found that the micro/mesoporous structures in zeolite catalysts help inhibit the loss of crystallinity and maintain acidity, resulting in better stability and activity during catalyst regeneration. Hierarchical ZSM-23 zeolites showed lower deposited coke amounts and activation energy values for the thermal oxidation process, providing superior performance and lower energy levels for regeneration compared to microporous zeolites.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Chemistry, Multidisciplinary
Juan Gancedo, Laura Faba, Salvador Ordonez
Summary: The condensation reaction between alkylated furans and alkenes using ZSM-5 zeolite catalyst in gas phase showed improved aromatic production and stability.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Shinya Kokuryo, Koji Miyake, Yoshiaki Uchida, Shunsuke Tanaka, Manabu Miyamoto, Yasunori Oumi, Atsushi Mizusawa, Tadashi Kubo, Norikazu Nishiyama
Summary: Plastic waste is causing severe environmental problems, and catalytic cracking is a promising solution. This study successfully synthesized a Zr- and Al-incorporated Beta zeolite catalyst, which showed enhanced efficiency in decomposing plastic waste. The findings contribute to the practical application of plastic waste treatment.
Review
Chemistry, Multidisciplinary
Eelco T. C. Vogt, Donglong Fu, Bert M. Weckhuysen
Summary: Hydrocarbon conversion catalysts can suffer from deactivation due to deposition or formation of carbon deposits, which is thermodynamically favored above 350 degrees C. Different mechanisms, such as carbenium-ion based mechanism, metal-induced soft coke formation, radical-mediated mechanism, and fast-growing carbon filament formation, contribute to the deactivation. The deactivation is caused by the blocking of pores and active sites by carbon deposits. Proper catalyst and process design can mitigate the effects of deactivation, and new analytical tools allow for direct observation of coke-type species distribution as a function of catalyst structure and lifetime.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Alessia Cesarini, Sharon Mitchell, Guido Zichittella, Mikhail Agrachev, Stefan P. Schmid, Gunnar Jeschke, Zeyou Pan, Andras Bodi, Patrick Hemberger, Javier Perez-Ramirez
Summary: Operando PEPICO spectroscopy distinguishes the mechanisms of hydrocarbon generation in the zeolite-catalysed conversions of methanol and methyl chloride. The study reveals different pathways and reaction products in the methanol-to-hydrocarbons and methyl chloride-to-hydrocarbons reactions. Additionally, variations in the formation of coke precursors have an impact on the catalyst's lifespan.
Article
Chemistry, Physical
Jose Valecillos, Hector Vicente, Ana G. Gayubo, Andres T. Aguayo, Pedro Castano
Summary: This study develops a spectro-kinetic approach to investigate the methanol to hydrocarbons reaction over a ZSM-5 zeolite catalyst. By combining in situ spectroscopic techniques and online product analysis, the time-and space-resolved evolution of the reaction media is obtained. The study focuses on the effect of space time and the tuning of other parameters to elucidate the reaction and deactivation mechanisms.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Physical
Mingyu Jin, Myungwon Oh, Minkee Choi
Summary: This study synthesized a hierarchical BEA zeolite with trimodal porosity and found that it exhibited remarkable catalytic performance and deactivation resistance in the isobutane/butene alkylation reaction, reducing the operating costs of the reaction.
Article
Chemistry, Physical
Mingyu Jin, Myungwon Oh, Minkee Choi
Summary: This study investigates the effect of molecular transport on selectivity and deactivation in isobutane/butene alkylation using different BEA zeolites. The results show that the hierarchical BEA zeolite with trimodal porosity exhibits enhanced selectivity and catalytic lifetime, reducing operating costs.
Article
Chemistry, Analytical
Guanshuai Zhang, Shanjian Liu, Dongmei Bi, Zhisen He, Jia Liu, Yinjiao Liu
Summary: Hydrogen peroxide pretreatment was applied for fast pyrolysis of corn stalks, and it was found that the pretreatment effectively promoted lignin depolymerization and decreased the reaction activation energy. The pretreatment also increased the cellulose content and removed alkali and alkaline earth metals from the biomass. The pH of the hydrogen peroxide solution affected the removal of lignin and ash by the pretreatment, and the composition of bio-oil changed significantly, with a significant increase in the relative content of levoglucosan after pretreatment.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2024)