Impact of Xylose on Dynamics of Water Diffusion in Mesoporous Zeolites Measured by NMR

Abstract

Zeolites are known to be effective catalysts in biomass converting processes. Understanding the mesoporous structure and dynamics within it during such reactions is important in effectively utilizing them. Nuclear magnetic resonance (NMR) T2 relaxation and diffusion measurements, using a high-power radio frequency probe, are shown to characterize the dynamics of water in mesoporous commercially made 5A zeolite beads before and after the introduction of xylose. Xylose is the starting point in the dehydration into furfural. The results indicate xylose slightly enhances rotational mobility while it decreases translational motion through altering the permeability, K, throughout the porous structure. The measurements show xylose inhibits pure water from relocating into larger pores within the zeolite beads where it eventually is expelled from the bead itself.

Water Confinement on Polymer Coatings Dictates Proton–Electron Transfer on Metal-Catalyzed Hydrogenation of Nitrite

“…This technique can shed light into the translational motion of molecules, namely, by biexponential fitting of the diffusion decays . This has been successfully used in the past to identify populations of confined water molecules even in small quantities. , …”

“… 14 This has been successfully used in the past to identify populations of confined water molecules even in small quantities. 15 , 16 …”

“…14 This has been successfully used in the past to identify populations of confined water molecules even in small quantities. 15,16 Diffusional motions of water were investigated herein by inverse Laplace transform to interrogate the multiple environments present in the system. In each experiment, we studied the diffusion of water at low and high temperatures.…”