Structure and dynamics of cumene and 1,2,4-trimethylbenzene mixture in NaY zeolite: a molecular dynamics simulation study

A molecular dynamics study of 1:1 mixture of the C9 isomers, isopropyl benzene (cumene) and 1,2,4-trimethylbenzene (124TMB) (pseudocumene), in zeolite NaY is reported. Structural and dynamical properties have been computed to understand possible difficulties in the separation of these isomers. Cumene exhibits a slightly higher self-diffusivity. 124TMB encounters a larger barrier as compared with cumene at the 12-ring window during migration from one supercage to another. 124TMB has a significantly larger backscattering during rotation which may be attributed to its shape and large cross-sectional diameter as compared with cumene. Cumene has a higher rotational diffusivity. Results suggest that there is larger difference between the rotational diffusivities of the two isomers and little difference in their translational diffusivity. It may be possible to exploit this difference in separating the two isomers.