Promotion of Ni/MCM-41 Catalyst for Hydrogenation of Naphthalene by co-Impregnation with Polyols

The activities of nickel supported on MCM-41 catalysts, prepared by co-impregnation with polyols （ethylene glycol, glycerol, xylitol, sorbitol and glucose）, were investigated by hydrogenation of naphthalene. Compared with the conventional wetness impregnation, addition of moderate polyols into the metal nitrate support surface, resulting in formation of persion of the active phase and significant aqueous solution could enhance interaction with very small NiO particle size （〈5 nm）, high discatalytic activity. Particle size of Ni^0 decreased from 36.1 nm to below 5 nm; meanwhile the complete hydrogenation of naphthalene was dependent on the Ni^0 particle size. The hydrogenation activities of the catalysts prepared by co-impregnation with polyols were very high with 100% conversion even at iow temperature of 55 ℃.

Thermodynamics and kinetics insights into naphthalene hydrogenation over a Ni-Mo catalyst

Hydrocracking represents an important process in modern petroleum refining industry,whose performance mainly relies on the identity of catalyst.In this work,we perform a combined thermodynamics and kinetics study on the hydrogenation of naphthalene over a commercialized NiMo/HY catalyst.The reaction network is constructed for the respective production of decalin and methylindane via the intermediate product of tetralin,which could further undergo hydrogenation to butylbenzene,ethylbenzene,xylene,toluene,benzene,methylcyclohexane and cyclohexane.The thermodynamics analysis suggests the optimum operating conditions for the production of monoaromatics are 400℃,8.0 MPa,and 4.0 hydrogen/naphthalene ratio.Based on these,the influences of reaction temperature,pressure,hydrogen/-naphthalene ratio,and liquid hourly space velocity(LHSV)are investigated to fit the Langmuir-Hinshelwood model.It is found that the higher temperature and pressure while lower LHSV favors monoaromatics production,which is insensitive to the hydrogen/naphthalene ratio.Furthermore,the high consistence between the experimental and simulated data further validates the as-obtained kinetics model on the prediction of catalytic performance over this kind of catalyst.

Chelators to assist the high dispersion of Ni_(2)P particles over mesoporous silica nanospheres for hydrogenating reaction

NizP supported catalysts exhibit high catalytic activities in hydrogenation reaction,of which the particle sizes of Ni_(2)P active phases are the key influential factor.This research focus on the effect of chelators on the size of Ni_(2)P particles over wrinkle silica nanoparticles(WSNs)by introducing chelating agents EDTA and NTA during impregnation process.The characterization results show that chelators modified cata-lysts possess smaller size of Ni_(2)P particles than the unmodified Ni_(2)P catalysts.Among all the synthesized catalysts,the EDTA modified Ni_(2)PE(1.5)/WSNs catalyst possesses smallest average particle size of Ni_(2)P,only 2.6 nm.Moreover,the Ni_(2)P catalysts with the assistance of EDTA exhibits better catalytic activity than that of NTA under high reaction temperature,which can be ascribed to the strong bonding between EDTA and Ni.And the EDTA modified Ni_(2)PE(1.5)/WSNs catalyst shows highest hydrogenation ability,almost reaching 100%decalin selectivity.