Shape-selectivity in 2,6-dimethylnaphthalene synthesis over ZSM-5: Computational analysis using density functional theory

In this work, we performed a computational analysis of the molecular dimensions of the dimethylnaphthalene (DMN) isomers and the reactivity difference of different carbon atoms in 2-methylnaphthalene (MN) by using density functional theory. Calculation results indicated that 2,7-DMN is slightly smaller than 2,6-DMN in molecular dimension, which can easily explain the unusual 2,6-/2,7-DMN ratio observed in experiment, that is, the 2,6-/2,7-DMN ratio decreases when the pore of ZSM-5 is narrowed. Besides, the calculation of reactivity descriptors show the position 6 in 2-MN is more reactive than position 7, which suggests that formation of 2,6-DMN is electronically more favored than that of 2,7-DMN.