Purification of 2,6-Diisopropylnaphthalene by Static Melt Crystallization from a Mixture Containing Diisopropylnaphthalene Isomers

• Published in: Chinese journal of chemistry Vol. 25; no. 1; pp. 108 - 112
• Main Author: 田正华 贾宏敏 赵桂利 胡伟琪
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 2007; WILEY‐VCH Verlag
• Subjects: 2,6-二异丙基萘; 2,6‐diisopropylnaphthalene; 6-diisopropylnaphthalene; crystallization rate; eutectic temperature; static melt crystallization; sweating rate; 共晶温度; 同分异构体; 混合物; 静态熔化结晶
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.200790002

2,6-Diisopropylnaphthalene （2,6-DIPN）, as the precursor of important monomer 2,6-naphthalene dicarboxylic acid, could be produced by the shape-selective isopropylation of naphthalene with propene resulting in an isomeric mixture having different alkylation levels. Since the boiling points of DIPNs were very close and the differences of melting points in-between isomers were quite distinctive, the static melt crystallization was applied to separate and purify 2,6-DIPN from its isomers. 2,6-DIPN with purity ≥99% was produced through a process of three stages： crystallization→sweating→melting. The phase diagram of 2,6-DIPN-2,7-DIPN binary system was plotted to opti- mize the temperature control of crystallization. By repeated crystallization of melts with different concentration levels, the yield of pure 2,6-DIPN could be enhanced to 87%. No solvent was necessary. Keywords 2,6-diisopropylnaphthalene, static melt crystallization, crystallization rate, sweating rate, eutectic temperature