Solvent Free Selective Isomerization Of  p-diethylbenzene To m-diethylbenzene Using Modified Hβ Zeolites

Organic Chemistry Research Laboratory, Institute of Chemical Technology, N.M. Parekh Road, Matunga, Mumbai 400 019, India

Adv. Mater. Lett., 2014, 5 (10), pp 550-556

DOI: 10.5185/amlett.2014.2586

Publication Date (Web): Nov 09, 2014

Copyright © IAAM-VBRI Press

E-mail: samantsd@yahoo.com

Abstract

Solvent free and selective isomerization of p-diethylbenzene (p-DEB) to m-diethylbenzene (m-DEB) was carried out using metal modified zeolite Hβ at high temperature. The metal modification of Hβ catalyst was carried out by using typical Lewis acidic cations Al³⁺, Fe³⁺, Ti⁴⁺, Sn⁴⁺ and Sb³⁺. The catalysts were characterized by XRD, FE-SEM, HR-TEM, FT-IR, N₂-desorption (BET), ICP-AES, NH3-TPD, pyridine-IR, and TGA techniques for structure, morphology, acidity and stability. Particle size of the crystallites was determined by HR-TEM and the size was in the range of 15 - 35 nm. At 250oC, Al-Hβ, Fe-Hβ and Ti-Hβ catalysts showed 69 - 75% conversion of p-DEB with 43 - 51% selectivity towards m-DEB. This process is a greener alternative to the classical AlCl₃ process. Further, such an isomerization would make the styrene manufacture more economic.

Keywords

Zeolite H&beta, diethylbenzene, isomerization, heterogeneous catalysis, cation exchange