Selective Hydrogenation Of Naphthalene,Pyrene And Phenanthrene Over Modified Skeletal Ni

Polycyclic aromatic hydrocarbons (PAHs) are derived from coal tar and petroleum compounds. The hydrogenation products of PAHs can be used not only as hydrogen donor solvents in coal liquefaction but also as the intermediates for function materials and medicines. In this thesis, selective hydrogenation of naphthalene, pyrene and phenanthrene over modified skeletal Ni (MS-Ni) prepared by rapidly quenching technique was investigated. The effects of reaction parameters such as solvent type, temperature, pressure and initial concentration of the substrate were investigated. The reaction pathways of pyrene and phenanthrene hydrogenation over different catalysts were studied.The hydrogenation of naphthalene to tetralin over MS-Ni was investigated. Under optimal conditions of 50℃, 1.0MPa, both the conversion of naphthalene and the selectivity to tetralin were up to 100%. The MS-Ni catalyst was repeatedly used for 10 times, the activity and high selectivity of tetralin was maintained, indicating the excellent stability of catalyst. Moreover, the effects of reaction parameters on the hydrogenation of naphthalene to decalin were investigated over MS-Ni catalyst. Results revealed that the optimized reaction temperature was 140℃. The high reaction temperature and low reaction pressure significantly improved the mass ratio of trans-decalin to cis-decalin.Selective hydrogenation of pyrene over MS-Ni catalyst in liquid phase gave rise mainly to 1,2,3,6,7,8-hexahydropyrene. High selectivity of 1.2,3,6,7,8-hexahydropyrene was up to 76.9% under 150℃and 0.6MPa when the conversion was 100%. The reaction pathways of pyrene hydrogenation over Rh/C, Ru/C, Pd/C were studied and results showed that the main product was 4,5,9,10-tetrahydropyrene. Catalytic activity for pyrene hydrogenation was found in the order of Rh/C>Ru/C>Pd/C, which was opposite to the order of the main product selectivity.The application of MS-Ni catalyst was studied by hydrogenation of phenanthrene to 1,2,3,4,5,6,7,8-octahydropyrene. The MS-Ni catalyst showed excellent selectivity to 1,2,3,4,5, 6,7,8-octahydropyrene. Excellent 100% phenanthrene conversion and 95.1% 1,2,3,4,5,6,7,8-octahydropyrene selectivity were obtained in one-pot reaction under 150℃and 1.0MPa. The reaction pathway of phenanthrene hydrogenation over Pd/C catalysts was investigated and results showed that the main product was 9,10-dihydrophenanthrene.