Recent advances in the preparation of 2,6-dimethylnaphthalene

Poly(ethylene naphthalate) (PEN) is a high-performance engineering polyester with critical applications in multiple fields such as precision packaging and aerospace systems. Nevertheless, its industrial-scale implementation remains constrained by the high production costs of its crucial precursor, 2,6-dimethylnaphthalene (2,6-DMN). This review has comprehensively summarized the preparation methods for 2,6-DMN, which are categorized into direct extraction and catalytic synthesis. Direct extraction achieved high-purity 2,6-DMN from coal/petroleum-derived oils via multi-stage purification cascades. Catalytic synthesis techniques are divided into four distinct pathways: (i) o -xylene alkenylation with butadiene, (ii) p -xylene/C 4 olefin coupling, (iii) toluene acylation, and (iv) naphthalene (NAPH)/2-methylnaphthalene (2-MN) methylation. Among these, zeolite-catalyzed alkylation of NAPH/2-MN with methanol demonstrated compelling industrial potential due to its cost-effective feedstocks and simplified process. We further highlight mechanistic insights into alkylation pathways and reactant diffusion dynamics, which have driven intensive research into the design of zeolite catalysts, particularly the regulation of acidity and pore architecture to enhance shape-selectivity. Using representative zeolites (HZSM-5, HZSM-12, SAPO-11) as model systems, we critically evaluated structure-activity relationships in catalyst modification strategies, including acid site density modulation, mesoporosity introduction and surface passivation, along with their corresponding impact on methylation performance. Finally, four strategic research priorities are proposed to advance next-generation catalysts for scalable and economically sustainable 2,6-DMN production.