Catalysis

Using Graphene Encapsulated Ni and Pd Catalysts with Solvent Effect to Achieve Highly Chemo-Selective Hydrogenation of 4-Nitrostyrene to Different Products

Authors

  • Jianguo Liu Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, PR China. & CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China. ,
  • Jiangmin Sun CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Ener-gy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China. ,
  • Shanshan Lin CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Ener-gy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China. ,
  • Longlong Ma CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Ener-gy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China

Abstract

Chemo-selective hydrogenation of challenging nitrostyrene to the corresponding product of vinylaniline, ethylbenzenamine, and ethylnitrobenzene separately in high yield is difficult since there exists competitive activation of the C=C double bond and the –NO2 group over most supported metal catalysts. Also, the currently reported catalysts still have some disadvantages of high cost, catalyst reusability and separation problem, catalyst stability and leaching during harsh reaction conditions, waste generation, which disagree with the requirements of low cost, highly active and selective, sustainable, environmentally friendlier, and industrially applicable. Herein we report thin graphene layer encapsulated Ni and Pd nanoparticles core-shell structures as highly active, chemo-selective, and reusable catalysts for hydrogenation of 4-nitrostyrene in both batch reactor and industrially applicable flow reactor. In the standard hydrogenation of 4-nitrostyrene, the optimized catalysts Ni/[email protected] and [email protected] yield a selectivity to every single product of 4-vinylaniline 99%, 4-ethylbenzenamine 99%, 1-ethyl-4-nitrobenzene 99% through simple changing reaction conditions, the best achieved over Ni and other group metals and higher than the best result reported in the literature. In non-polar solvent toluene, in contrast to traditional catalysts, the [email protected] catalyst is inert for the C=C and is only active about the -NO2, while the N-doped [email protected] has opposite hydrogenation ability and can hydrogenate the C=C without touching -NO2 in non-polar solvent cyclohexane, which rarely reported in the previous literature. In addition, the catalysts show excellent stability and the 4-nitrostyrene’s hydrogenation can be successfully applied in industrially applicable flow reactors for each of the three product syntheses separately with excellent yield. These discoveries may extend the design of non-noble catalysts with excellent chemoselectivity for use in fine chemicals’ synthesis.

Content

Thumbnail image of Manuscript-0808-ChemRxiv.pdf