Selective conversion of furfuryl alcohol to 1,2-pentanediol over a Ru/MnOx catalyst in aqueous phase

The partial hydrogenation of benzene to cyclohexene is an economically interesting and technically challenging reaction. Over the last four decades, a lot of work has been dedicated to the development of an exploitable process and several approaches have been investigated. However, environmental constraints often represent a limit to their industrial application, making further research in this field necessary. The goal of this review is to highlight the main findings of the different disciplines involved in understanding the governing principles of this reaction from a sustainable chemistry standpoint. Special emphasis is given to ruthenium-catalyzed liquid phase batch hydrogenation of benzene.

Benzene partial hydrogenation: advances and perspectives

The design of an ideal heterogeneous catalyst for hydrogenation reaction is to impart the catalyst with synergetic surface sites active cooperatively toward different reaction species. Herein a new strategy is presented for the creation of such a catalyst with dual active sites by decorating metal and metal oxide nanoparticles with ultrafine nanoclusters at atomic level. This strategy is exemplified by the design and synthesis of Ru nanoclusters supported on Ni/NiO nanoparticles. This Ru-nanocluster/Ni/NiO-nanoparticle catalyst is shown to exhibit ultrahigh catalytic activity for benzene hydrogenation reaction, which is 55 times higher than Ru-Ni alloy or Ru on Ni catalysts. The nanoclusters-on-nanoparticles are characterized by high-resolution transmission electron microscope, Cs-corrected high angle annular dark field-scanning transmission electron microscopy, elemental mapping, high-sensitivity low-energy ion scattering, and X-ray absorption spectra. The atomic-scale nanocluster-nanoparticle structural characteristics constitute the basis for creating the catalytic synergy of the surface sites, where Ru provides hydrogen adsorption and dissociation site, Ni acts as a "bridge" for transferring H species to benzene adsorbed and activated at NiO site, which has significant implications to multifunctional nanocatalysts design for wide ranges of catalytic reactions.

Ultrafine Nanoparticle-Supported Ru Nanoclusters with Ultrahigh Catalytic Activity.

Ru–Zn supported on hydroxyapatite as an effective catalyst for partial hydrogenation of benzene

The hydrogenation of benzene in organic phase leads rapidly to cyclohexane. A very simple catalyst system comprising only supported ruthenium in water with the addition of the ionic liquid 1 (R=Me) in the ppm range catalyzes the extremely difficult selective hydrogenation of benzene to cyclohexene. It is not necessary to add large amounts of salt (ZnSO₄) or other metals, which is otherwise done to control selectivity.

Ruthenium-Catalyzed Selective Hydrogenation of Benzene to Cyclohexene in the Presence of an Ionic Liquid†

Progress in Ru-Based Amorphous Alloy Catalysts for Selective Hydrogenation of Benzene to Cyclohexene

Selective hydrogenation of benzene to cyclohexene on Ru-based catalysts promoted with Mn and Zn

A novel Ru-Zn catalyst was prepared by coprecipitation. The catalyst was characterized by XRF, XRD and TEM. The effects of organic additives on the performance of the Ru-Zn catalyst for benzene selective hydrogenation to cyclohexene were investigated. The results showed that the catalyst was composed of Ru and Zn in molar ratio of 33.8:1, and the most probable value of the Ru crystallite size in the catalyst was 5.1 nm. The modification of Ru with Zn and the small size effect were the main cause why the catalyst exhibited the high activity and the excellent cyclohexene selectivity. When PEG (polyethylene glycol) was used as an additive, the activity of the catalyst decreased, and the cyclohexene selectivity increased with the increase of the PEG molecular weight. With the addition of PEG-20000, a cyclohexene selectivity of 78.9% at a benzene conversion of 68.7% and a maximum cyclohexene yield of 61.4% were obtained. With diethanolamine and triethanolamine as additives, cyclohexene yields were as high as 58.9% and 58.2%, respectively.

Wei Guo

Papers

Progress in Ru-Based Amorphous Alloy Catalysts for Selective Hydrogenation of Benzene to Cyclohexene

Selective hydrogenation of benzene to cyclohexene on Ru-based catalysts promoted with Mn and Zn

Effect of Organic Additives on the Performance of Nano-sized Ru-Zn Catalyst

Monolayer Dispersed Ru-Zn Catalyst and Its Performance in the Selective Hydrogenation of Benzene to Cyclohexene

Selective Hydrogenation of Benzene to Cyclohexene over Ru-Zn Catalyst with Nanosized Zirconia as Dispersant