Pore mouth versus intracrystalline adsorption of isoalkanes on ZSM-22 and ZSM-23 zeolites under vapour and liquid phase conditions.

Methylbranched C5-C9 alkanes do not adsorb in the intracrystalline void space of ZSM-23, neither from the vapour nor the liquid phase, but are adsorbed in ZSM-22, if only from the liquid phase, and this despite the small difference in pore size.