Hydroisopropylation of refined naphthalene for preparing 2,6-diisopropylnaphthalene

ORGN 950

Zheng-Hua Tian, cghtzh@mail.asptt.ln.cn, Hong-Min Jia, Gui-Li Zhao, jhongmin@sohu.com, Ben Li, lib_en@126.com, and Wei-Qi Hu, jhongmin@sohu.com. School of Chemical Engineering, Anshan University of Science & Technology, Qianshan Zhonglu, Greenland IT City G-1, 221, Anshan, Liaoning Province, 114044, China
2,6-Diisopropylnaphthalene (2,6-DIPN), the precursor of important monomer 2,6-naphthalene dicarboxylic acid, was prepared by the hydroisopropylation of refined naphthalene with propene over shape-selective catalyst-steam-dealuminated H-mordenite (SDHM) in a 0.5 l autoclave, which resulted in an average value of naphthalene conversion, 2,6-DIPN selectivity and 2,6-DIPN yield as high as 92 %, 64 % and 35 % respectively. The deactivation of SDHM could be slackened under H2 atmosphere. Modification of SDHM with mixed rare earth further increased the selectivity and the yield of 2,6-DIPN. The static melt crystallization was applied to separate and purify 2,6-DIPN from its isomers. 2,6-DIPN with purity ≥99 % was produced. The phase diagram of 2,6-DIPN—2,7-DIPN binary system was plotted to optimize the temperature control of crystallization. The other DIPN and polyisopropylnaphthalene (PIPN) were converted into monoisopropylnaphthalene (MIPN) through the intermolecular transalkylation with naphthalene. MIPN reacted with propene to form 2,6-DIPN once again.