Ionic liquid-enhanced immobilization of biosynthesized Au nanoparticles on TS-1 toward efficient catalysts for propylene epoxidation

• Published in: Journal of catalysis 2011-10, Vol.283 (2), p.192-201
• Main Authors: Du, Mingming, Zhan, Guowu, Yang, Xin, Wang, Huixuan, Lin, Wenshuang, Zhou, Yao, Zhu, Jing, Lin, Ling, Huang, Jiale, Sun, Daohua, Jia, Lishan, Li, Qingbiao
• Format: Article
• Language: English
• Subjects: biochemical compounds; Biosynthesis; Catalysis; Catalyst; catalysts; Chemistry; Colloidal state and disperse state; Epoxy resins; Exact sciences and technology; General and physical chemistry; Gold; hydrogen; Immobilization; Ion-exchange; Ionic liquid; Ions; isoelectric point; Liquids; nanogold; Nanoparticles; oxygen; Physical and chemical studies. Granulometry. Electrokinetic phenomena; propylene; Propylene epoxidation; Special adsorption; Surface physical chemistry; temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; titanium; TS-1; Zeolites: preparations and properties
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2011.08.011

Biosynthesized gold nanoparticles (GNPs) were immobilized onto TS-1 through 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4]). [BMIM] + specially adsorbed onto the support to increase its isoelectric point, leading to the enhanced immobilization and high activity and stability for propylene epoxidation with H 2/O 2 mixture, probably attributing to enhanced interaction between the GNPs and TS-1 and the role of residual biomolecules in protecting the GNPs thereof. [Display omitted] ► The gold nanoparticles were prepared by biosynthesis method. ► Au nanoparticles were completely immobilized on TS-1 support with ionic liquid. ► Au/TS-1 catalysts exhibited high activity and stability for propylene epoxidation. ► About 4.6% of propylene conversion could be obtained. ► The isoelectric point of TS-1 could be changed by ionic liquid. The direct vapor-phase epoxidation of propylene in the presence of hydrogen and oxygen was studied at a space velocity of 7000 mL h - 1 g cat. - 1 over gold catalysts with varying gold and titanium contents prepared by ionic liquid-enhanced immobilization (ILEI) method in which biosynthesized gold nanoparticles (GNPs) were immobilized onto the titanium silicalite-1 (TS-1) supports through the assistance of a small amount of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4]). The results showed that [BMIM] + specially adsorbed onto the support to increase its isoelectric point, leading to the enhanced immobilization. The propylene conversion of 14.6% and PO formation rate of 164.4 g po K g cat. - 1 h - 1 were higher than those in any other reports, probably attributing to enhanced interaction between the GNPs and TS-1. Furthermore, the excellent activity and high selectivity of the Au/TS-1 catalysts at a relatively high reaction temperature might be attributed to the existence of residual biomolecules on the catalysts.