Enhanced ethene to propene ratio over Zn-modified SAPO-34 zeolites in methanol-to-olefin reaction

Abstract

The enrichment of incorporated Zn-related species and the accommodation of facilitated aromatics impose increased diffusion restriction for bulky hydrocarbons, thus contributing to significant improvements in ethene selectivity and ethene to propene ratio over Zn modified SAPO-34 zeolites.

Methanol-to-olefins catalysis on ERI-type molecular sieves: towards enhancing ethylene selectivity

“…and reaction conditions (temperature, feed composition, methanol partial pressure/weight hourly space velocity (WHSV), etc.) that influence the MTO reaction behavior, cage topology (or simply put, choice of framework) has been recognized as an important parameter that regulates olefins product distribution [3,22,25,26,30,32,34,40,[46][47][48][49][50][51][52][53][54][55][56][57]. This is the case because a cage structure impacts/restricts the type of HP species that can be formed.…”

Metal–organic framework-assisted synthesis of Zr-modified SAPO-34 zeolites with hierarchical porous structure for the catalytic transformation of methanol to olefins

“…4 further reveal the presence of macropores inside the crystals of the hierarchically structured Zr x -SAPO-34 zeolites. The initial conversion of methanol strongly depends on the structural integrity of the catalysts; 28 the SAPO-34, Zr 0.25 -SAPO-34, Zr 0.50 -SAPO-34 and Zr 0.75 -SAPO-34 zeolites will be discussed systematically in a follow-up study.…”

“…The transformation of methanol to light olefins is an acid-catalyzed reaction; the methanol conversion and product diffusion are related to the acid natures of the zeolites. 28 Therefore, it is of vital significance to differentiate the acid properties of the SAPO-34, Zr 0.25 -SAPO-34, Zr 0.50 -SAPO-34 and Zr 0.75 -SAPO-34 zeolites. The NH 3 -TPD technique was employed to analyze the acid properties of the SAPO-34, Zr 0.25 -SAPO-34, Zr 0.50 -SAPO-34 and Zr 0.75 -SAPO-34 zeolites.…”

“…13 Also, the increase of the number of total acid sites in hierarchical SAPO-34 can contribute to prolonging the catalytic lifetime. 28…”

Modulation of SAPO-34 Property with Activated Seeds and Its Enhanced Lifetime in Methanol to Olefins Reaction

“…As such, various strategies have been developed for controlling the acid sites to obtain the highly active SAPO-34 catalyst with a long lifetime. These strategies include adjusting the silicon content [22][23][24] , metal heteroatom modification (by isomorphous substitution of heteroatoms, ion exchange, or impregnation) [25][26][27][28][29] , silanation [30][31] , seed-assisted synthe-sis [32] , and recently reported low-temperature synthesis approach [33] . Among these strategies, seed-assisted synthesis was probably the most intriguing one because the seeding approach has been proven to own a high capability of modulating the physico-chemical properties of zeolites by changing the crystallization kinetics.…”