Influence of temperature inhomogeneity on product profile of reactions occurring within zeolites

Abstract

In zeolites, diffusion is often accompanied by a reaction or sorption which in turn can induce temperature inhomogeneities. Monte Carlo simulations of Lennard-Jones atoms in zeolite NaCaA are reported for the presence of a hot zone presumed to be created by a reaction or chemi-or physi-sorption site. These simulations show that the presence of localized hot regions can alter both kinetic and transport properties such as diffusion. Further, we show that enhancement of diffusion constant is greater for systems with larger barrier height, a surprising result that may be of considerable significance in many chemical and biological processes. We find an unanticipated coupling between reaction and diffusion due to the presence of a hot zone in addition to that which normally exists via concentration. Implications of this coupling for the product profile of a reaction are discussed. We also propose a mechanism by which mobility of ions or diffusion of molecular species within biomembranes may take place.

Propene Adsorption-Chemisorption Behaviors on H-SAPO-34 Zeolite Catalysts at Different Temperatures

“…In general, low-temperature conditions were found to be helpful in inhibiting the chemisorption of propene on the highly acidic H-SAPO-34 catalysts, which can facilitate propene separation and allow for reliable monitoring of kinetic parameters. issues related to this product, including separation of propene from its mixture [7-9] and design of new catalytic materials to increase its production yield, stability, and recyclability [9][10][11][12][13][14][15][16]. To understand and cope with these issues, researchers are exploring different strategies.…”

“…Such studies require experimental data free of any coupling or oligomerization reactions. Some literature have shown that propene reacts with zeolites [13,[17][18][19][20][21]. However, exact conditions of propene-zeolite reaction remain unclear, that is, whether propene reacts with every zeolite or whether there are exceptional circumstances is unknown.…”