Wenqiang Du

Selective hydrogenation of cinnamaldehyde over Pt nanoparticles deposited on reduced graphene oxide

The selective hydrogenation of cinnamaldehyde was investigated with Pt nanoparticles deposited on reduced graphene oxide (Pt/RGO). Compared with carbon nanotubes (CNTs) or activated carbon (AC) as support, Pt/RGO showed the best activity and selectivity for the hydrogenation of CO bond.

Selective Hydrogenation of Single Benzene Ring in Biphenyl Catalyzed by Skeletal Ni

Selective catalytic hydrogenation of unsaturated compounds has been attracting worldwide attention for decades. Many interesting results have been reported on various substrates with different catalyst systems, such as chemoselective hydrogenation of nitrobenzene on supported Au, partial hydrogenation of dinitrobenzene to nitroanilines on Ru/C, and selective hydrogenation of p-phenylphenol to p-cyclohexylphenol on Pd/C. However, very limited knowledge has been accumulated on the selective catalytic hydrogenation of a single benzene ring in a molecule containing two or more equal phenyl groups. Cyclohexylbenzene (CHB) is a highly valued chemical, which is typically applied as a synthetic intermediate or an electrolyte additive for overcharge protection in lithium ion batteries. In principle, CHB can be prepared by using several methods such as alkylation of benzene with cyclohexene, hydroalkylation of benzene, cross-coupling of alkyl halides with aryl Grignard reagents, and hydrodechlorination of chlorinated biphenyl. Among these methods, the alkylation technique shows advantageous characteristics and has been applied to industry; nevertheless the CHB yield is still poor . It is important to explore an efficient and environmentally benign approach for CHB production. Selective hydrogenation of biphenyl (BP) is known to be a superior technique. Selective hydrogenation of a compound containing two benzene rings was first reported in 1949 by H. Smith et al, in which Pd/C, Ru/C, Pt/C and Rh/C were studied. Later in 1968, a patent claimed the selective hydrogenation of BP to CHB using supported Pd, Pt, Ru and Rh as catalysts. Then, the hydrogenation activity of sulfided mixed oxide of Co and Mo on Al2O3 was studied. The BP hydrogenation was also performed under different conditions, for example in dilute aqueous alkaline solution or in supercritical carbon dioxide. Although these previous efforts have been attractive in terms of catalysis, the low atom-economic efficiency needed to be improved. Herein, we present a novel and highly efficient technology for the extremely selective catalytic hydrogenation of BP to CHB over skeletal Ni (S-Ni or Raney Ni). The most active skeletal Ni catalyst was prepared from rapidly quenched Ni–Al alloys with Mo as a promoting additive. Excellent 100 % BP conversion and 99.4 % CHB selectivity were obtained in a one-pot reaction. The kinetic equation for the hydrogenation of BP to CHB was also established. Theoretically, hydrogenation of BP is a typical consecutive reaction containing at least two steps (Scheme 1). CHB is the

Quenched skeletal Ni as the effective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons

Quenched skeletal Ni is an active and selective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons (PAHs). The molecular structure of PAHs significantly dominate the hydrogenation process and furthermore, the distribution of hydrogenated products.