Unifying Principles in Zeolite Chemistry and Catalysis

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

“…In the literature one can find many other types of shape selectivity, such as the "concentration" or "solvent" effect, 435,436,[438][439][440][441] the "confinement" or "solvent" effect, 444,445,500,501 molecular traffic control, 467,502 secondary shape selectivity, 466 inverse shape selectivity, 469 and the "cage" or "window" effect. 357,359 …”

“…In the late 1970s, Rabo recognized that the activity is remarkably high because FAU-type zeolites adsorb and thereby concentrate reactants relative to the gas phase. 435 Although the (radical) reaction that Rabo ended up choosing to illustrate this "concentration effect" [435][436][437][438][439][440][441] is a source for dispute, 442 the concept itself was successfully extended to other reactions and zeolites by Derouane, who renamed it the "confinement effect". 363,443 For more than two decades, this concept was developed not as an instance of shape selectivity but as an instance of a "confinement effect" 444 or "solvent effect".…”

Effect of different levels and particle sizes of perlite on serum biochemical factors of broiler chicks

“…In addition, perlite having ion exchange properties and the ability of bivalent cations absorption, increases blood Mg. Meanwhile, Rabo (1976) stated that aluminosilicates are thermodynamically unstable and tend to generate insoluble aluminate and soluble silicate in acidic and water environments and this transformation easily occurs in chicks' gastrointestinal tract with pH 5. It seems that in the condition of increasing dietary perlite level to 5%, silicate produced in the gastrointestinal tract, combines with Mg ions and prevents their absorption.…”

Surface Active Sites of Modified Zeolites and Zirconia in the Conversion of Nitrogen(I, II) Oxides

“…To identify the nature of acid centres, some catalyst samples were studied by IR spectroscopy using pyridine as the molecular probe. -1 which appears in the spectrum of sample 3 can also be attributed to proton Brönsted acid centres (Rabo 1980;Little 1980). Comparison of the data on catalyst activity in reactions involving nitrogen(I) oxide decomposition and reduction by light alkanes and carbon monoxide (also in excess oxygen) with the acid properties of the catalyst surface demonstrates the existence of a definite correlation between the strength of the Brönsted acid centres and the activity of the catalyst in the SCR of N 2 O. Iron-containing catalysts based on Y zeolite which contained only weak Lewis and Brönsted acid centres desorbed ammonia at 220 o C and were, consequently, less activity in the reactions studied relative to catalysts based on other zeolite structural types.…”