Preparation of 2,6-Diisopropylnaphthalene(2,6-DIPN) by the Shape-Selective Isopropylation of Naphthalene over Synthetic Mordenite

2,6-DIPN is a precursor of 2,6-naphthalene dicarboxylic acid (2,6-NDA) which is an important monomer for making advanced polyester materials and liquid crystalline polymers. The more advanced method for preparing 2,6-NDA is the direct oxidation of 2,6-dialkylnaphthalene (2,6-DAN). Since isopropyl group is more hindered than methyl and ethyl group, a β-selective isopropylation could be expected in case of using shape selective zeolite catalysts instead of the conventional Friedel-Crafts alkylation. A particularly preferred catalyst is synthetic Mordenite having a specific Si/Al ratio, which results in a high selectivity of 2,6-DIPN. It is more beneficial to the separation and purification of 2,6-DIPN from its isomers. In this paper the study on isopropylation of naphthalene over various zeolites and different dealuminated H-mordenites (HM) is reported.