Enhancing the Catalytic Properties of Mordenites via an Alkali–Acid Treatment and by Loading Nickel–Cerium during o‑Ethyltoluene Isomerization

• Published in: ACS omega Vol. 6; no. 35; pp. 22688 - 22699
• Main Authors: Cao, Xiaoyan, Wang, Ruiyun, Wang, Kaijun, Gu, Zhenggui, Wang, Fang
• Format: Journal Article
• Language: English
• Published: American Chemical Society 07.09.2021
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.1c02809

The catalytic performance of the selective isomerization of o-ethyltoluene (O-ET) is crucial to increasing the m-ethyltoluene (M-ET) and p-ethyltoluene (P-ET) yields. During the isomerization of O-ET, traditional (commercial) mordenites (HM) are generally limited by a high reaction temperature (235 °C), as well as a low yield of the isomerization product (49.0%). In this study, micro-mesoporous mordenites were obtained by treating commercial mordenites with NaOH, NaOH–HNO3, and NaOH–mixed acid (HNO3–oxalic). Thereafter, their structure, porosity, and acidity were investigated via X-ray diffraction, transmission electron microscopy, inductively coupled plasma, N2 sorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy of pyridine, temperature-programmed desorption of ammonia, and nuclear magnetic resonance. Among the various treated samples, the accessibility of the acidic sites and the B/L value of the alkali–mixed HNO3–oxalic one were enhanced, achieving the highest yield (53.6%) and lowest reaction temperature (165 °C), thus significantly reducing the energy consumption of the reaction process. Furthermore, Ni and Ce were successfully loaded via the incipient wetness impregnation of the micro-mesoporous mordenite to significantly prolong the catalytic life. This study affords a new strategy for obtaining high M-ET and P-ET yields from the isomerization of O-ET in mixed C9 aromatics on an industrial scale.