Preparation of 2-Methylnaphthalene from 1-Methylnaphthalene via Catalytic Isomerization and Crystallization

Hao Sun (Jiangsu Key Laboratory for Biomass Energy and Material, National Engineering Laboratory for Biomass Chemical Utilization, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Nanjing 210042)
Kang Sun (Jiangsu Key Laboratory for Biomass Energy and Material, National Engineering Laboratory for Biomass Chemical Utilization, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Nanjing 210042)
Jianchun Jiang (Jiangsu Key Laboratory for Biomass Energy and Material, National Engineering Laboratory for Biomass Chemical Utilization, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Nanjing 210042)
Zhenggui Gu (Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023)

Bulletin of Chemical Reaction Engineering & Catalysis
2018: BCREC Volume 13 Issue 3 Year 2018 (December 2018)

Large amounts of residual 1-methylnaphthalene are generated when 2-methylnaphthalene is extracted from alkyl naphthalene. In order to transform waste into assets, this study proposes a feasible process for preparing 2-methylnaphthalene from 1-methylnaphthalene through isomerization and crystallization. The 1-methylnaphthalene isomerization was carried out in a fixed-bed reactor over mixed acids-treated HBEA zeolite. The results showed that acidic properties of catalysts and reaction temperature were associated with the 2-methylnaphthalene selectivity, yield and catalytic stability. At a high reaction temperature of 623 K, the 2-methylnaphthalene yield was 65.84 %, and the deactivation rate was much lower. The separation of reaction products was then investigated by two consecutive crystallization processes. Under optimal conditions, the 2-methylnaphthalene purity attained 96.67 % in the product, while the yield was 87.48 % in the refining process.