Synthesis of Beta zeolite for isomerization of Hexane

Abstract

Isomerization of n-hexane on zeolite Beta was studied. Zeolite Beta was synthesized from appropriate gels and crystallized under the controlled temperature and pressure contitions. Zeolite Beta can be synthesized within a wide range of silica-to-alumina ratio (30-80). Techniques including XRD, XRF, BET, SEM AND NH3-TPD have been used for the characterization of zeolite Beta. Platinum ion-exchanged Beta zeolite exhibited high activity and selectivity for 2,2-Dimethylbutane (2,2-DMB), 2,3-Dimethylbutane (2,3-DMB), 2-Methylpentane (2-MP) and 3-Methylpentane (3-MP). As high as 72% of n-hexane conversion and 98% of product selectivity were obtained at 250°C, 1600 h⁻¹ for 20 min on stream. The influences of various reaction parameters such as reaction temperature, space velocity, amount of platinum leading, and stability of the catalyst were also studied. Pt/H-Beta zeolite was recommended as one of the promising catalyst for n-hezane isomerization due to its high activity and stability. The combined effect of the higher amount of strong acid site possessed by H-Beta and the dehydrogenation role played by Pt was believed to be responsible for the good catalytic performance of Pt/H-Beta.