Conversion of methanol to hydrocarbons over zeolite ZSM-23 (MTT): exceptional effects of particle size on catalyst lifetime

Abstract

A variety of synthetic procedures have been used to obtain zeolite ZSM-23 (MTT) catalysts with crystallite sizes ranging from the micrometer to nanometer scale. When the acidic zeolite is used as a catalyst for the methanol to hydrocarbon (MTH) reaction, the catalytic lifetime is dramatically influenced by the crystallite shape and size.

Topology-dependent hydrocarbon transformations in the methanol-to-hydrocarbons reaction studied by operando UV-Raman spectroscopy

“…having multiple orders of porosity or peculiar crystal shapes) are known to improve the catalytic activity because of the better transport properties of these structures, however without deeply altering the reaction mechanism proper of a specific topology. [43][44][45][46][47] Operando experiments were conducted exploiting the features of the modified Linkam CCR1000 microreactor previously reported by the authors. 33 In brief, the catalyst samples were pressed to pellets, crushed, and sieved to obtain a particle size of 150-300 µm.…”

Recent trends and fundamental insights in the methanol-to-hydrocarbons process

“…Selectivity to propylene can be further improved by optimizing acidic properties of zeolites leading to up to 53 % of propylene selectivity at 450 o C, 86 while optimization of textural properties dramatically prolongs catalyst lifetime. 87 For zeolites with intersections, two cycles work in parallel, and propagation of one cycle over the other can be achieved by other means (Fig. 5 e,f).…”

Benzene co-reaction with methanol and dimethyl ether over zeolite and zeotype catalysts: Evidence of parallel reaction paths to toluene and diphenylmethane

“…The testing of other 10-ring zeolites with an absence of cavities, TON and MTT, which are characterized by straight channels, resulted in almost complete suppression of the arene cycle. The product effluent was dominated by C5+ aliphatics in the range of the gasoline fraction, but interestingly aromatics-free [64,[154][155][156][157]. Therefore, the specific dimensions of pore channels and cavities, inherent to every zeolitic topology, set spatial constraints that play an important role in directing the dominant catalytic cycle in MTH.…”