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Recent Patents on Catalysis (Discontinued)
ISSN (Print): 2211-548X
ISSN (Online): 2211-5498
DOI: 10.2174/2211548X03666140204003651      Price:  $100

Selective Isomerization of p-Diisopropylbenzene to m-Diisopropylbenzene Over Metal Modified Hβ Zeolites

Author(s): Mahesh S. Edake and Shriniwas D. Samant
Pages 130-141 (12)
Isomerization of p-diisopropylbenzene (p-DIPB) to m-diisopropylbenzene (m-DIPB) was carried out using metal modified Hβ zeolites at high temperature and in the absence of a solvent. The metal cations used for the modification of Hβ were typical Lewis acidic cations Fe3+, Al3+, Ti4+, Sn4+ and Sb3+. The modified zeolite catalysts were heated at 120oC, and calcined at 280oC, and 550oC. They were characterized by XRD, FE-SEM, HR-TEM, FT-IR, N2-desorption (BET), NH3-TPD, Pyridine-IR and TGA techniques for structural, morphological, acidity and stability investigation. Particle size of the crystallites was determined by HR-TEM analysis and the size was in the range of 15-35 nm. At 250oC, Al- Hβ, Fe-Hβ and Ti-Hβ showed 68-75% conversion of p-DIPB and 42-54% selectivity towards m-DIPB. The calcination temperature had no effect on the activity. Isomerization increases with increased acidity. Thus, metal modified Hβ catalysts are excellent, efficient, and alternative heterogeneous catalysts for the isomerization of p-diisopropylbenzene (p- DIPB) to m-diisopropylbenzene (m-DIPB). This process is a greener alternative for the classical AlCl3 process as discussed in the article along with the relevant patents.
Diisopropylbenzene, heterogeneous catalysis, isomerization, metal modified zeolite Hβ, rearrangement of dialkylbenzenes.
Organic Chemistry Research Laboratory, Department of Chemistry, Institute of Chemical Technology, N.M. Parekh Road, Matunga, Mumbai 400 019, India.