Pore entrance size, molecular catalysts

Encapsulating Molecular Catalyst in Nanoreactors by Reducing the Pore Entrance Size... 

These catalytic routes are associated with increased coke formation which can lead to catalyst deactivation. The preparation of Ga-containing ZSM-5 zeohte has been shown to decrease the pore size as compared to ZSM-5 (Choudhary et al., 2002) due to Ga oxides forming and depositing in channels or pore entrance (Choudhary et al., 2002 Al-Yassir et al., 2012). A decrease in pore size can explain the inhibition of polycychc aromatic hydrocarbons (eg, naphthalenes) due to their larger molecular size than monoaromatics (Jae et al., 2011). Shape-selective catalysis can continue monoaromatic hydrocarbon (eg, benzene, toluene, and xylene) production, while inhibiting the relatively larger polycychc aromatic hydrocarbons. 

A preformed molecular catalyst is first adsorbed into the nanocages of MS (SBA-16 or FDU-12), followed by finely reducing the size of pore entrance by a silylation reaction according to the molecular size and properties of the catalyst, reactants, and products, to prevent the molecular catalyst from leaching out of the nanocages (Scheme 10.9) [65]. Thereby, the molecular catalyst is confined in the mesoporous... 

---