A comparative molecular dynamics study of diffusion of n-decane and 3-methyl pentane in Y zeolite

作者：Pazzona F G^*; Borah B J; Demontis P; Suffritti G B; Yashonath S

来源：Journal of Chemical Sciences, 2009, 121(5): 921-927.

DOI：10.1007/s12039-009-0109-5

• Hydrocarbon
• diffusion
• levitation effect
• zeolite
• separation

Molecular dynamics simulations are reported on the structure and dynamics of n-decane and 3-methylpentane in zeolite NaY. We have calculated several properties such as the center of mass-center of mass rdf, the end-end distance distribution, bond angle distribution and dihedral angle distribution. We have also analysed trajectory to obtain diffusivity and velocity autocorrelation VACF). Surprisingly, the diffusivity of 3-methylpentane which is having larger cross-section perpendicular to the long molecular axis is higher than n-decane at 300 K. Activation energies have been obtained from simulations performed at 200 K, 300 K, 350 K, 400 K and 450 K in the NVE ensemble. These results can be understood in terms of the previously known levitation effect. Arrhenious plot has higher value of slope for n-decane (5 center dot 9 kJ/mol) than 3-methylpentane (3 center dot 7 kJ/mol) in agreement with the prediction of levitation effect.

• 出版日期2009-9