RSC Advances Blog

Graphene is one of the most exciting and promising materials to have emerged into the laboratory in recent years. Among its many possibilities it can be used as a support for various catalysts, such as the highly-dispersed ultrafine platinum nanoparticles synthesised by Baoqiang Sheng and colleagues at Key Laboratory of Organic Synthesis of Jiangsu Province in China.

The group used their graphene-supported platinum catalysts to reduce various unsaturated compounds, including not only C-C double and triple bonds but also nitroarenes. These could be selectively converted to their corresponding functionalized anilines – important intermediates in the preparation of polymers, urethanes, dyes, pharmaceuticals, and other industrially-important chemical products.

They claim  excellent yields (over 99% in most cases) under mild conditions, with the ability to accelerate the reaction rate by increasing the pressure to 4 atm, giving complete hydrogenation products in ten minutes.

The paper provides details of the preparation and characterisation of the supported catalysts, and lists the experimental procedures together with results of the reductions that were carried out.

This article is currently free to access through the RSC Advances website:

Highly-dispersed ultrafine Pt nanoparticles on graphene as effective hydrogenation catalysts, Baoqiang Sheng, Lei Hu, Tingting Yu, Xueqin Cao and Hongwei Gu, RSC Adv., 2012, 2, 5520–5523

Being green is very important these days: and yet it’s important not to compromise on the activity and selectivity of our catalytic reactions. A quick look through recent issues of RSC Advances shows that chemists are not sleeping on their laurels when it comes to recyclable and reusable catalysts which are nevertheless active for a whole range of reactions.

Just to take some examples: Subhankar Santra and colleagues from India have developed a simple process for decorating palladium nanoparticles onto single-walled carbon nanotubes – those versatile carbon-based supports – and tested the resulting catalyst in a copper-free acyl Sonogashira reaction. Most importantly they were able to recycle the catalyst up to seven times; it is to be hoped that further optimisation would increase this number still further.

Meanwhile also from India, Mithu Saha et al. have been working on a ligand-free palladium(0) nanoparticle-catalysed reaction that works in water. They tested the catalyst for the synthesis of bis(heterocyclyl)methane derivatives. They report good yields and reused the catalyst four times.

A novel approach to catalyst separation was taken by Zhijie Wu et al. in China, who made a magnetic core–shell nanocomposite, Fe3O4@SiO2@Pd-Au, for liquid-phase hydrodechlorination of 4-chlorophenol – an important reaction for the disposal of chlorophenol waste. They optimised the catalyst preparation and composition and, after magnetic separation, could reuse the catalyst at least eight times.

All these articles are available through the RSC Advances website, and are free to access so now is a good time to read about this fascinating research.

Anchored palladium nanoparticles onto single walled carbon nanotubes: Efficient recyclable catalyst for N-containing heterocycles, Subhankar Santra , Priyadarshi Ranjan , Parthasarathi Bera , Prasenjit Ghosh and Swadhin K. Mandal, RSC Adv., 2012, 2, 7523-7533

Pd(0) NPs: a novel and reusable catalyst for the synthesis of bis(heterocyclyl)methanes in water, Mithu Saha , Amarta Kumar Pal and Shibaji Nandi, RSC Adv., 2012, 2, 6397-6400

Fe3O4@SiO2@Pd-Au: a highly efficient and magnetically separable catalyst for liquid-phase hydrodechlorination of 4-chlorophenol, Zhijie Wu , Chongxia Sun , Yan Chai and Minghui Zhang, RSC Adv., 2011, 1, 1179-1182

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By Sara Coles