Vapor‐ and liquid‐phase adsorption of alcohol and water in silicalite‐1 synthesized in fluoride media

Abstract

In this work, batch-adsorption experiments and molecular simulations are employed to probe the adsorption of binary mixtures containing ethanol or a linear alkane-1,n-diol solvated in water or ethanol onto silicalite-1. Since the batch-adsorption experiments require an additional relationship to determine the amount of solute (and solvent) adsorbed, as only the bulk liquid reservoir can be probed directly, molecular simulations are used to provide a relationship between solute and solvent adsorption for input to the experimental bulk measurements. The combination of bulk experimental measurements and simulated solutesolvent relationship yields solvent and solute loadings that are self-consistent with simulation alone, and allow for an assessment of the various assumptions made in the literature. At low solution concentrations, the solute loading calculated is independent of the assumption made. At high concentrations, a negligent choice of assumption can lead to systematic overestimation or underestimation of calculated solute loading.

The Shape of Water in Zeolites and Its Impact on Epoxidation Catalysis

“…[5][6][7][8][9] Water (H 2 O) molecules within microporous environments form intricate structures through hydrogen bonds (HB) that impact the stability of adsorbates, intrapore diffusion coefficients, and surface reactions. Decades of work have shown that HBs among aqueous solvents and polar surfaces can affect the adsorption of alcohols within microporous solids, [8][9][10][11][12][13][14] transport of H 2 O through carbon nanotubes, [15][16][17] and the stability of reactive surface intermediates within zeolites. 5,6,[18][19][20][21] The role of confined water in biocatalysis, however, is more clearly understood due to the successful characterization of water structures within the catalytic clefts of enzymes.…”

The Shape of Water in Zeolites and Its Impact on Epoxidation Catalysis

“…The presence of silanol defects ((SiOH) x ; i.e., the hydrophility of a material) stabilizes H 2 O within zeolite pores and impacts adsorption energies for H 2 O within BEA and MFI zeolites. 6,7,10,14,19,20,31,[36][37][38] The literature, however, lacks an understanding for how the structures that H 2 O forms depends on the combination of zeolite topology and (SiOH) x densities. Moreover, the thermochemical properties of these H 2 O structures will likely exhibit a complex dependence on the pore diameter and (SiOH) x density, because the importance of SiOH functions may change as H 2 O loses opportunities to hydrogen bond via spatial constraints.…”

“…[5][6][7][8][9] Water (H 2 O) molecules within microporous environments form intricate structures through hydrogen bonds (HB) that impact the stability of adsorbates, intrapore diffusion coefficients, and surface reactions. Decades of work have shown that HBs among aqueous solvents and polar surfaces can affect the adsorption of alcohols within microporous solids, [8][9][10][11][12][13][14] transport of H 2 O through carbon nanotubes, [15][16][17] and the stability of reactive surface intermediates within zeolites. 5,6,[18][19][20][21] The role of confined water in biocatalysis, however, is more clearly understood due to the successful characterization of water structures within the catalytic clefts of enzymes.…”

Smart Molecular Recognition: From Key-to-Lock Principle to Memory-Based Selectivity

“…In solid state, this phase transition is observed if the initial host is non-porous (Gorbatchuk et al, 2002). If the host has a permanent porosity combined with flexible structure, like that of some metal organic frameworks (MOFs) (Hiraide et al, 2016;Engel et al, 2017) or silicalites (DeJaco et al, 2019), the initial part of sorption isotherm may have the shape of Langmuir isotherm followed by a sigmoidal step. This step is called the gate-opening or breathing (Afonso et al, 2012;Lee et al, 2019).…”