Skeletal isomerisation of oleic acid over ferrierite: Influence of acid site number, accessibility and strength on activity and selectivity

Large Ferrierite Crystals as Models for Catalyst Deactivation during Skeletal Isomerisation of Oleic Acid: Evidence for Pore Mouth Catalysis

“…[49] With the 10-MR extremities occupied and blocked by the "coke" species, the observed fluorescenced istribution is clearly consistent with the alkyl iso- Figure 8. Polarised 2D wide-fieldfluorescence micro-spectroscopy images recorded for af lat spent model H-FER crystal collectedf rom experiment 8( non-distilled EA reactant with 1.0 wt.…”

“…The synthesis of the large H-FER crystalsr equired for such studies has been reported in the literature [43,44] and these model catalysts have been used in an umber of fundamentaldiffusion studies. [45][46][47] In this work, we build on our recent results on ferrierite deactivation obtained with bulk characterisationt echniques [18,49] and study the deactivation of H-FER during the skeletal isomerisationo fO Au sing large zeolite crystals as model catalysts, in order to seek additional evidences upporting the concept of pore mouth catalysis, as illustrated in Figure 1. To further substantiate and confirmt his hypothesis at the molecular level, the precised istribution of carbonaceous deposits in individual zeolite crystalsh as been investigated.…”

Molecular behaviour of phenol in zeolite Beta catalysts as a function of acid site presence: a quasielastic neutron scattering and molecular dynamics simulation study

“…3 This is emphasised by the observed reduction in diffusion in going from an all-silica to acidic zeolite and highlights the need of a thorough optimization of the Si/Al ratio in order to maximise yield and selectivity, and decrease coke formation. 91 The reduction of molecular diffusion as a consequence of agglomeration is stronger in the all-silica structure, but less significant in the acidic structure, as long as the acid sites are not oversaturated by the number of phenol molecules. In the all-silica zeolite, the diffusion coefficients are reduced on average by 26 and 43% when the loadings are increased from 1 to 2 mpuc and from 2 to 4 mpuc, respectively.…”

The role of external acidity of meso-/microporous zeolites in determining selectivity for acid-catalyzed reactions of benzyl alcohol

“…The textural properties of HLBM zeolite samples, however, are not influenced obviously by changing Si/Al ratios in the synthesis, as indicated by similar surface areas and pore volumes of the HLBM-3/36 samples with different Si/Al ratios in Table S1 of the Supplementary Information. The external acidity commonly results from acid sites located on the external surface and at the pore mouth region of the hierarchical zeolite catalysts [36][37][38]. The creation of mesoporosity or delamination in HLBM zeolites increases the number of acid sites both in the pore mouth region and on the external surface compared to the microporous MFI zeolite.…”