X. Nie, M. Janik, Xinwen Guo
Feb 3, 2012
Citations
0
Influential Citations
32
Citations
Journal
Journal of Physical Chemistry C
Abstract
Methylation of 2-methylnaphthalene (2-MN) for synthesis of 2,6-dimethylnaphthalene (2,6-DMN) is an industrially important reaction because 2,6-DMN is a key precursor for the advanced polymer material polyethylenenaphthalate. Shape-selective methylation of 2-MN with methanol in an H-ZSM-5 pore was studied using the ONIOM2 model and density functional theory. Two proposed reaction mechanisms, stepwise and concerted, were considered. Computational results reveal that the stepwise path, with methanol dehydration to produce a methoxide intermediate as the rate-limiting step, is kinetically favored. Both the stepwise and concerted path indicated that methylation at the 6-position is favored over methylation at the 7-position; however, the concerted path shows a greater selectivity. 2-MN isomerization and methylation, which may occur on the catalyst external surface and decrease selectivity to the desired 2,6-DMN product were also examined. Isomerization of 2-MN to 1-MN proceeds faster on external surface sites ...