Configurational-Bias Monte Carlo (CB-MC) calculations of n-alkane sorption in zeolites RHO and FER

A newly-developed Monte Carlo method is used to simulate the energetics, location and conformation of n-alkanes from butane to decane inside all-silica polymorphs of zeolites rho and ferrierite. Sorption in ferrierite yields far larger heats of adsorption than in rho. In rho, the alkanes adopt highly coiled conformations within the alpha-cages of the structure, whereas in ferrierite they are confined to all-trans conformations within the 10-ring channel. Only butane is distributed over both the 8-ring and 10-ring channels of ferrierite in the approximate ratio of 1:2. An increase in temperature to 498 K has little effect on the heats of adsorption, locations or conformations of the alkane