Separation of Diisopropylnaphthalene Isomers: Advances and Challenges in the Petrochemical Industry

Owing to the use of a more rigid naphthalene ring instead of a benzene ring in its structure, polyethylene naphthalate (PEN) has better engineering properties than polyethylene terephthalate (PET). The industrial production of PEN is limited by the inability to obtain enough high-purity synthetic raw materials, and 2,6-diisopropylnaphthalene (2,6-DIPN) as a competitive raw material product has gradually become popular. Besides the synthesis protocol, the purification of 2,6-DIPN is of great significance due to the complex composition of the liquid products. In this paper, the technical methods for purifying 2,6-DIPN from naphthalene isopropylation products are reviewed. The current state of the development, merits, and drawbacks of each kind of technical method (distillation, crystallization, and adsorption) that is feasible for industrial production in this field are discussed to achieve efficient 2,6-DIPN synthesis and purification.