Progress in shape-selective synthesis of 2,6-dialkylnaphthalene over zeolite

2,6-Dialkylnaphthalene is a valuable organic chemical material. The shape-selective syntheses of 2,6-dialkylnaphthalene, which use naphthalene or methylnaphthalene as reactants, are considered as the most rational technical route. Several factors that influence shape-selective synthesis of 2,6-dialkylnaphthalene over zeolite such as alkylating reagents, solvents and selection of zeolites are reviewed. It is known that acidic zeolite catalysts have several advantages such as high activity, excellent selectivity and environmentally benign catalysis, among which HY, Hβ, SAPO-5, HZSM-5 and MCM-41 are in common use. Alkylating reagents can be divided into four types which are alcohol, alkene, halogenate hydrocarbon and alkyl aromatic hydrocarbon. Compared to tetralin, carbon dioxide and isooctane, cyclohexane is the most widely used solvent.