Liquid-phase Catalytic Transfer Hydrogenation of Aromatic Nitro Compounds over Nickel-doped Carbon Catalysts

Ni-doped carbon aerogel catalysts were prepared through sol-gel polycondensation of furfural with resorcinol in the presence of nickel nitrate salts, followed by drying at ambient pressure and then carbonization in N2. The catalysts were used for catalytic transfer hydrogenation of aromatic nitro compounds with propan-2-ol as hydrogen donor and KOH as promoter, and have been found to exhibit excellent catalytic activity for transfer hydrogenation of nitrobenzene, chloronitrobenzene and nitrotoluene. The results show that the yield of the products could reach as high as 100% within 3 hours. The effect of nickel loading amount (ranging from 2.5 to 20 wt%) on the catalytic activity was also studied. It has been found that the nickel amount has little effect on the catalytic activity. The reusability of the catalysts was also addressed. It is interesting to note that the catalytic activity of the catalysts remain at the same level even after six cycles, which is evidenced by the excellent yield of the target products. The recycled catalyst can be easily recovered from the reaction medium by a magnetically separable approach.