Catalyst of Palladium Supported on H-Beta Zeolite with Nanosized Al₂O₃ for Isomerization of n-Hexane

Abstract

Synthesis isoparaffins from light naphtha was studied using n-hexane conversion. The main target products were multi-branched isoparaffins. Which are harder to form than mono-branched isoparaffins in the zeolitic pores. Nano-technology was applied to form composites of zeolites and nano-sized (defined as 5-50 nm, and here called ns) oxides, to improve the state of metal species for isomerization into multi-branched isoparaffins. Skeletal isomerization of n-hexane was advanced, based on catalyst optimization with 0.1-2 wt% Pt or Pd on 35 wt% ns Al₂O₃ or ns SiO₂ and 65 wt% H-BEA zeolite (SiO₂/Al₂O₃ = 16-39). The presence of ns Al₂O₃ in the catalyst increased the mechanical strength of the shaped zeolite catalyst and reformed the surface acidity of the zeolite to milder acid suitable for skeletal isomerization without cracking. X-ray photoelectron spectroscopy showed that the nano-alumina dispersed and combined to the anisotropic surface of BEA zeolite to form an ionic and highly developed surface for palladium dispersion to improve the catalyst activity and selectivity.