n - Hexane 개질반응을 위한 HY 제올라이트 담지 Pt 및 Pt - Re 이원금속 촉매의 활성도 , 선택도 및 안정성에 관한연구

Abstract

Pt and Pt-Re bimetallic clusters supported on HY zeolite were prepared and their catalytic activities, selectivities and stabilities were evaluated in the n-hexane reforming reaction. The mole ratio of H₂/n-hexane was 5 and the reaction temperature and calcination temperature were varied in the range of temperature between 300 and 500℃, respectively. The selectivity of the HY zeolite supported catalyst towards C_6 isomers was 2 times higher than that of the alumina supported catalyst. The catalytic activity and selectivity of Pt-Re/HY are dependent on the temperature of calcination and the higher selectivity to C₁-C_5 products was obtained with Pt-Re/HY catalyst. The value of hydrogen chemisorption (H/M) of Re/HY is negligible and H/M value of Pt(0.5)Re(0.5)/HY is about one over third of that of Pt(0.5)/HY. These results indicate that Pt-Re bimetallic clusters were formed on HY zeolite. The addition of Re on Pt caused the deactivation rate to be decreased to one half of deactivation rate of Pt/HY catalyst. The selectivity of Pt-Re/HY towards C_6 isomers is lower than that of Pt/HY, while the selectivity to cracking products is higher than that of Pt/HY.