Tuning Morphology of Zn/HZSM‐5 for Catalytic Performance in Methanol Aromatization

Abstract

Catalytic performance is influenced by the morphology and assembly of catalyst particles. Therefore, Zn ion‐doped HZSM‐5 zeolite with different morphological structures is prepared using post‐treatments of selective dissolution and recrystallization, causing silicon components to migrate from the interior to the exterior in the different template etching processes. The core–shell, hollow, and hierarchical core–shell Zn/HZSM‐5 microspheres with weak acid sites on the external surfaces are successfully synthesized. Hierarchical core–shell‐structured Zn/HZSM‐5 microspheres with a silicon‐rich surface layer are prepared using an etching method in n‐butylamine solution. Their catalytic activity is investigated in methanol aromatization. The functionalized morphological Zn/HZSM‐5 catalysts show good catalytic performance and the silicon‐rich surface layer improves selectivity of p‐xylene in the reaction of methanol to aromatics.

Methods for Preparing Hierarchical Zeolites by Chemical Etching and Their Catalytic Applications: A Review

“…It is speculated that the strong coordinating effect of the C 2 O 4 2À group may be one of the reasons for the degradation of the framework. The analysis of zeolites treated with oxalic acid using 29 Si and 27 Al MAS NMR revealed that the 29 Si spectra of the oxalic acid-treated samples closely resembled those of the precursors. However, the 27 Al MAS NMR spectra exhibited a new peak at À 10 ppm due to the presence of frameworkisolated hexacoordinated aluminum.…”

Realization of rapid synthesis of H-ZSM-5 zeolite by seed-assisted method for aromatization reactions of methanol or methane

“…8 shows the performance of 6%Mo/H-ZSM-5-SAS-1 h and 6%Mo/H-ZSM-5-seed catalyst in the MTB reaction under 700℃ and 0.1 MPa, total flow rate is 25 mL/min and 0.4 g catalysts. All curves of CH 4 conversion shows an induction period, 40,41 it is due to the active sites (Mo 2 C and MoO x C y ) were formed at the beginning of the reaction, which is important for the aromatization activity of the catalyst. 40 The conversion of CH 4 reached a maximum value at 6 min, but then declines gradually with time on stream.…”

“…All curves of CH 4 conversion shows an induction period, 40,41 it is due to the active sites (Mo 2 C and MoO x C y ) were formed at the beginning of the reaction, which is important for the aromatization activity of the catalyst. 40 The conversion of CH 4 reached a maximum value at 6 min, but then declines gradually with time on stream. The yield of benzene reached a maximum value at 21 min, but then declines gradually with time on stream.…”

Energy‐Efficient Methanol to Dimethyl Ether Processes Combined with Water‐Containing Methanol Recycling: Process Simulation and Energy Analysis

“…DME has been regarded as an excellent alternative clean fuel to liquefied petroleum gas (LPG) and diesel because of its similar physicochemical properties as LPG and high cetane number with very low soot formation in the exhausted gas of diesel engines. [3] In general, the DME synthesis process can be divided into two: a Methanol-to-DME (MTD) process and a Syngas-to-DME (STD) process. [2] In addition, DME not only can be used as a clean fuel, but also as a starting material or an intermediate to produce various chemical products such as aromatics, methyl acetate, and formaldehyde.…”

“…[2] In addition, DME not only can be used as a clean fuel, but also as a starting material or an intermediate to produce various chemical products such as aromatics, methyl acetate, and formaldehyde. [3] In general, the DME synthesis process can be divided into two: a Methanol-to-DME (MTD) process and a Syngas-to-DME (STD) process. [1] In the MTD process, DME is synthesized by methanol dehydration using solid acid catalysts such as γ-Al 2 O 3 , zeolites (HZSM-5, HZSM-22), and composite oxides (SiO 2 /Al 2 O 3 , WOx/TiO 2 ).…”