A scanning pulse reaction technique for transient analysis of the methanol-to-hydrocarbons reaction

Ca Cations Impact the Local Environment inside HZSM-5 Pores during the Methanol-to-Hydrocarbons Reaction

“…To study the effect of Ca 2+ on the composition of molecules, confined inside the zeolite pores, we used the scanning pulse gas chromatography (SP-GC) method described previously. 15 We modified this method, so that the strength of the interaction of water and hydrocarbons with the catalyst can be gauged, providing quantitative information on the amount of mobile hydrocarbons and water retained in the zeolite pores during the reaction. The experiments consisted of identical periodic switches between a flow containing methanol and Ar tracer balanced by He to a dry He flow ( Figures 5 , S5–S6, and S10 ) followed by GC analysis.…”

“…In a previous work, we used a transient pulse reaction technique to show that HZSM-5 and Ca/ZSM-5 contain different amounts of different hydrocarbon pool intermediates. While HZSM-5 mainly contained aromatic hydrocarbons, aliphatics were predominant in the pores of Ca/ZSM-5 . In addition to hydrocarbons, water is another MTH product ofthat might affect the reaction. , Recent reports by the group of Lercher emphasize that tighter confinement in zeolite pores, induced by adsorbed water clusters, strongly influences alcohol dehydration activity. − Inspired by these findings, we hypothesize that the particular catalytic properties of alkaline earth-modified zeolites can be linked to the modification of the microporous space by strongly adsorbed molecules.…”

“…Step-Response Reaction Experiments. We adapted the scanning pulse-gas chromatography method describe previously 15 for periodic step-response experiments. The approach is schematically illustrated in Figure S5.…”

“…While HZSM-5 mainly contained aromatic hydrocarbons, aliphatics were predominant in the pores of Ca/ZSM-5. 15 In addition to hydrocarbons, water is another MTH product ofthat might affect the reaction. 16 , 17 Recent reports by the group of Lercher emphasize that tighter confinement in zeolite pores, induced by adsorbed water clusters, strongly influences alcohol dehydration activity.…”

Role of Strontium Cations in ZSM-5 Zeolite in the Methanol-to-Hydrocarbons Reaction

“…A total of 5 zeolite catalysts were synthesized, namely, HZSM-5, 0.1Sr/ZSM-5, 0.2Sr-ZSM-5, 0.4Sr/ZSM-5, and Na/ZSM-5. The proton form HZSM-5 was obtained by calcining a commercial NH 4 ZSM-5 powder (Alfa Aesar) at 550 °C for 5 h. x Sr/ZSM-5 catalysts (where x is the Sr content, i.e., 0.11, 0.22, and 0.44 mmol g –1 ) were prepared by incipient wetness impregnation of the calcined zeolites in their proton form with aqueous solutions of Sr­(NO 3 ) 2 (Alfa Aesar, 99.0%), following a procedure described elsewhere . The targeted Sr contents were 1, 2, and 4 wt %.…”