Effects of channel structure and acidity of molecular sieves in hydroisomerization of n-octane over bi-functional catalysts

• Published in: Catalysis letters 2005-03, Vol.100 (1-2), p.59-65
• Main Authors: Yunfeng, Hu, Xiangsheng, Wang, Xinwen, Guo, Silue, Li, Sheng, Hu, Haibo, Sun, Liang, Bai
• Format: Article
• Language: English
• Subjects: Acids; Ammonia; Catalysis; Chemistry; Exact sciences and technology; Flat panel displays; General and physical chemistry; Isomerization; Materials selection; Molecular sieves; Molecular structure; Pore size; Porosity; Selectivity; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-004-3086-9

SAPO-5, −11, −31, −41, −34, ZSM-5, −22 and −23 were synthesized by using the hydrothermal method and characterized by various methods such as XRD, SEM, XRF and TPD of NH3. They are representative of large-pore, medium-pore, small-pore, weak acid, strong acid, monodimensional channel and zigzag channel type of molecular sieves. Effects of pore size, the number of acid sites over medium-pore SAPOs, acid strength and shape of medium-pore channel on hydroisomerization of n-octane were examined over Pt-loaded corresponding molecular sieves. These results indicate that the selectivity to isomerization in hydroisomerization of n-octane is highly influenced by channel structure in molecular sieves and the conversion activity of n-octane is dependent on acidity of molecular sieves. Monodimensional medium-pore molecular sieves are ideal catalytic materials for higher isomerization selectivity in hydroisomerization of n-octane regardless of acid strength, such as SAPO-11, −31, −41, ZSM-22 and −23.