Methane aromatization on Zn-modified zeolite in the presence of a co-reactant higher alkane: How does it occur?

Recent progress in methane dehydroaromatization: From laboratory curiosities to promising technology

“…However, Liu et al [203] did observe C 1 incorporation via mass spectral analyses of aromatic fragments produced from the reaction of 13 CH 4 with propane as co-reactant. Recently, Stepanov et al [4,23,214] demonstrated the incorporation of 13 C-label in the products of coaromatization of 13 CH 4 with propane over a Zn/H-BEA catalyst at 550−600 • C, using 13 C solid-state NMR spectroscopy and GC-MS analysis.…”

Investigation of the stability of Zn-based HZSM-5 catalysts for methane dehydroaromatization

“…Most of the existing Zn-based HZSM-5 catalysts are reported for dehydroaromatization of light alkanes (C 3+ ) with a reaction temperature ranging between 500 and 600 • C [26][27][28]. The main drawback of light alkanes dehydroaromatization over Zn/HZSM-5 include the high yield of methane, which is a side product formed during reactant cracking.…”

“…the economic value of the process. A second issue is the rapid coke formation from these light alkanes compared to MDA, which deactivate the catalyst rapidly, even at lower reaction temperatures [26][27][28]. Finally, the stability of Zn-based catalysts represents another challenge, where Zn oxide can get reduced into Zn metal and vaporized under the reductive environment of the reaction [29,30].…”

Non-oxidative methane aromatization by bimetallic (La, Co, Pd and Pt) M-Zn/HZSM-5: Impact of propane addition

“…15%) over Zn-or Gapromoted zeolite catalysts [7,8]. It was recently found that 13 CH 4 can be converted into aromatics in the presence of C 3 H 8 at moderate temperatures (ca. 823 K) over an HZSM-5 catalyst impregnated with Ga, Re, Zn, Cu-Zn, Mo-Zn, Pt-Zn, and La-Zn [9].…”

“…Subsequent dimerization of the CH 2 species results in ethylene which, upon oligomerization and dehydrocyclization, converts into aromatics [6]. More recently, Luzgin et al [13] used 13 C labeled methane and found that methane was not involved in the aromatization reaction, but it was involved in methylation of aromatics that formed exclusively from propane in a temperature range of 823-873 K. Subsequent intramolecular rearrangements resulted in the involvement of methane carbon in the aromatic ring. The role of ZnO is to provide methoxy groups.…”