A novel Ru@GIS catalyst via interzeolite transformation for nylon 5X key monomer cadaverine synthesis

• Published in: Microporous and mesoporous materials 2024-03, Vol.368, p.113026, Article 113026
• Main Authors: Ma, Zhanling, Xin, Zongwu, Huang, Yuhong
• Format: Article
• Language: English
• Subjects: Decarboxylation; Interzeolite transformation; l-lysine; Oxygen vacancies
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2024.113026

l-lysine decarboxylation with zeolite-confined ruthenium (Ru) nanoparticle is a green and potential route to produce the new nylon 5X material key monomer cadaverine due to the low cost and overcapacity of l-lysine. Effect of zeolite frame-structure on decarboxylation performance is still an issue for effective synthesis of cadaverine. Through an inter-zeolite transformation strategy with Ru@FAU as crystal seed, Ru@GIS was synthesized and evaluated in l-lysine decarboxylation to clarify effect of channel size. FAU and GIS eutectic morphology (FAU/GIS) was also obtained by adjusting concentration of citric acid and crystallization time. Ru@GIS performed much better than Ru@FAU in l-lysine decarboxylation at 10 min with cadaverine productivity of 1120 g/L/h/mmol cat., which was triple than that in Ru@FAU (480.3 g/L/h/mmol cat.). Isothermal kinetics showed that conversion of l-lysine exhibited a typical characteristic of a first-order reaction with Ru@FAU and Ru@GIS. Abundant oxygen vacancies in Ru@GIS were supposed to play a vital role in stabilizing intermediate 2,6-diamino-1-hexanal, facilitating generation of target product cadaverine. The limited space in GIS can effectively inhibit side-reactions of cadaverine. The efficient performance of Ru@GIS provides a new route for efficient synthesis of nylon 5X key monomer cadaverine. Ru@GIS was synthesized through an inter-zeolite transformation strategy using Ru@FAU as crystal substrate for silicon and aluminum sources for GIS. Compared to Ru@FAU catalyst, Ru@GIS performed much better in l-lysine decarboxylation for cadaverine with a productivity of 1120 g/L/h/mmol cat. At 10 min, which was as high as triple that in Ru@FAU (480.3 g/L/h/mmol cat.). [Display omitted] •Ru@GIS was synthesized through an inter-zeolite transformation from Ru@FAU.•Initial selectivity of cadaverine was five times higher than that of Ru@FAU.•High productivity of cadaverine was reached to 1120 g L/h/mmol cat.