Abstract: A highly dispersed Ru-containing catalyst (5%Ru/C) was prepared and characterized byX-raydiffraction,X-rayphotoelectron spectroscopy, and high resolution transmission electron microscopy. The results showed that ruthenium was reduced to zero valence, and the average particle diameter of Ru crystallites was smaller than 5 nm. The ruthenium-based catalyst exhibited the highest activity for the hydrogenation of quinoline compared with other activated carbon-supported catalyst. Under the optimum reaction conditions of 100 ℃,p(H2)=3.0 MPa, and Ru/quinoline molar ratio of 4/1000, the main product obtained was the partially hydrogenated1,2,3,4-tetrahydroquinoline, and the selectivity was up to 98.5%. The decahydroquinoline was not found in the products. However, after the fresh 5%Ru/C catalyst was added,1,2,3,4-tertrahydroquinoline was completely transformed to decahydroquinoline. The mechanism of quinoline hydrogenation was also discussed.

Key words: ruthenium, activated carbon, catalytic hydrogenation, quinoline, 4-tetrahydroquinoline, decahydroquinoline