Improved Sythesis Of C₆Me₆Ru(0)C₆Me₆ As A Novel Catalyst For Hydrogenation Of Arenes

The synthesis route and application of some kinds of organometallic catalysts were introduced briefly in this paper. In addition, the research background of Ruthenium complex C6Me6Ru(0)C6Me6 was elaborated. Ru based catalysts were widely researched all over the world, but arene-ruthenium complexes as catalyst for selective hydrogenation of benzene to cyclohexene were rarely reported, especially the zero value ruthenium arene complexes. I have developed a synthetic route for C6Me6Ru(0)C6Me6. Under our experimental conditions, the overall yield of C6Me6Ru(0)C6Me6 could be reached to 37% based on RuCl3 and improved 18% than Fischer synthesis. This synthesis route had been applied for patent.Experimental results indicated that the lab synthesized organometallic compound C6Me6Ru(0)C6Me6 can be used as homogeneous catalyst for hydrogenation of benzene. TOF of benzene could be reached to 338h-1 under 1Oatm of hydrogen pressure under experimental conditions used. In addition, experimental tests indicated that C6Me6Ru(0)C6Me6 had good ability of selective hydrogenation of benzene to cyclohexene. The selectivity of cyclohexene production could be 10.8% when the conversion of benzene was 5.0% under experimental conditions used. Because of high additional value of cyclohexene, C6Me6Ru(0)C6Me6 has more developed potential. This organometallic compound C6Me6Ru(0)C6Me6 was also found to catalyze the hydrogenation of various benzene derivatives in homogenous phase. Toluene was hydrogenated slower than benzene, presumably due to the steric effects which was stronger than electronic effect. Therefore the TOF decreases for the benzene derivatives with bulky substituents because of the increasing steric effects. TOF of methylbenzene,p-dimethylbenzene, ethylbenzene were 87 h-1,64 h-1 59 h-1. In addition to the hydrogenation of aromatic ring, the alkene bond was also hydrogenated. The turnover for the hydrogenation of styrene to ethylbenzene was considerably higher than expected, ca.227h-1. Methylcyclohexane was, however, not detected at all by GC. Therefore this catalyst had considerable potential in organic synthesis, used to hydrogenate aromatic compounds. In addition, this compound can be used in organic synthesis as an effective homogenous catalyst for hydrogenation of benzene derivatives.