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Olefin Ring‐closing Metathesis under Spatial Confinement: Morphology−Transport Relationships
Author(s) -
Tallarek Ulrich,
Hochstrasser Janika,
Ziegler Felix,
Huang Xiaohui,
Kübel Christian,
Buchmeiser Michael R.
Publication year - 2021
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202001495
Subject(s) - mesoporous material , diffusion , chemical physics , confined space , materials science , porosity , tortuosity , chemical engineering , chemistry , nanotechnology , catalysis , organic chemistry , thermodynamics , composite material , physics , engineering
Spatial confinement effects on hindered transport in mesoporous silica particles are quantified using reconstructions of their morphology obtained by electron tomography as geometrical models in direct diffusion simulations for passive, finite‐size tracers. We monitor accessible porosity and effective diffusion coefficients resulting from steric and hydrodynamic interactions between tracers and pore space confinement as a function of λ = d tracer / d meso , the ratio of tracer to mean mesopore size. For λ =0, pointlike tracers reproduce the true diffusive tortuosities. For λ >0, derived hindrance factors quantify the extent to which diffusion through the materials is hindered compared with free diffusion in the bulk liquid. Morphology‐transport relationships are then discussed with respect to the immobilization, formation, and transport of key molecular species in the ring‐closing metathesis of an α,ω‐diene to macro(mono)cyclization product and oligomer, with a 2 nd ‐generation Hoveyda‐Grubbs type catalyst immobilized inside the mesopores of the particles.