| In the present paper, the main goal is to produce ruthenium nano-particle prepared by thermal decomposition of Ru3(CO)12 in benzene solvent and supported on nanoscale silica(The TEM micrograph of the new catalyst shows the size of Ru nano-particles is about 6nm), and to investigate their activity in benzene hydrogenation to cyclohexane. It is found that these Ru/SiO2 nanoparticle catalysts exhibit excellent benzene hydrogenation activity and convenient recycle use effect. Under the condition of benzene/Ru=10000(molar ratio),2.0 MPa of H2,90℃ of reaction temperature and 2.5h of reaction time,without any solvents,the conversion and cyclohexane yield all reach to 100%,TOF is 4000 molmor-1 h-1.Catalsts can be recycled 12 times and its activity has no evident fall. And TTO reaches to 117,000. The TEM micrograph of reused catalsts shows the size of Ru nano-particles congregating to about 50nm. Then add poly(ethylene glycol) of 400 average molecular weight (PEG-400) into the catalytic system as protective solvent to stablize the Ru nano-particles,and do hydroenation reaction of benzene. Under the condition of benzene/Ru=1000(molar ratio), 1.5g of PEG-400,5.0MPa of H2,130℃ of reaction temperature and 1.5h of reaction time, the conversion and cyclohexane yield all reach to 100%,TOF is just 666 molmor'h"1. Catalsts can be recycled 20 times and its activity has no fall. The TEM micrograph of recycled catalsts show the size of Ru nano-particles is not chang evidently.At last, the nanoscale catalysts of Ru/SiO2 have be applied in hydrogenating other aromatic compounds and get good result.
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