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Highlights in Chemical Technology

Chemical technology news from across RSC Publishing.



Microreactor's holey coat improves syntheses


04 December 2008

A thin catalytic coating on the walls of chemical reactors could make a wide range of industrial processes more efficient, say a team of European researchers.

TEM image of the porous titania thin film containing Pd nanoparticles

The pores in the titanium dioxide thin film hold the catalytic palladium nanoparticles

Many chemical syntheses, particularly those of pharmaceuticals, have hydrogenation as a key step. Scientists usually do the hydrogenation in slurry reactors, in which gas is bubbled through a suspension of solid catalyst, often palladium, in liquid. This process has drawbacks, says Angel Berenguer-Murcia, at the University of Cambridge, UK: 'The catalyst has to be filtered off and the product purified by one or more purification steps.'

Instead, Berenguer-Murcia and colleagues in Cambridge and at the Eindhoven University of Technology, The Netherlands, coated the walls of a microreactor with a thin porous film of titanium dioxide that contained palladium nanoparticles in its pores. They showed that the film catalysed the hydrogenation of phenylacetylene to styrene with comparable speed and selectivity to palladium nanoparticles in solution. They also found that the film was stable for more than a month of continuous use. 'As there is no leaching of the catalyst, separation and purification steps are not required. Thus, the overall efficiency of chemical processes can be considerably improved,' says Berenguer-Murcia.

"This method of incorporating catalysts into reactors is novel. It is evident that this elegant methodology could be used for other catalysts which would enable a greater array of reactions to be performed"
- Paul Watts, University of Hull, UK
Berenguer-Murcia used a microreactor because it has a much larger surface area to volume ratio than a batch reactor and so more of the reagents come into contact with the catalytic film. 'Microreactor technology enables the efficient synthesis of chemicals in higher yield and selectivity compared to batch reactor technology,' comments Paul Watts, an expert in miniaturisation at the University of Hull, UK. 'This method of incorporating catalysts into reactors is novel. It is evident that this elegant methodology could be used for other catalysts which would enable a greater array of reactions to be performed.'

'It is our hope that these developments will strongly impact on the nature and scale of process equipment, pilot plants, and production facilities and devices,' says Berenguer-Murcia. 'The process and chemical industry in Europe will have to at least maintain its present global position in a very competitive world by considerably strengthening its innovative power and increasing its research and development investments. This strong position relies on, among other factors, the availability and further development of innovative process equipment.'

Colin Batchelor

Link to journal article

Capillary microreactors wall-coated with mesoporous titania thin film catalyst supports
Evgeny V. Rebrov, Angel Berenguer-Murcia, Helen E. Skelton, Brian F. G. Johnson, Andrew. E. H. Wheatley and Jaap C. Schouten, Lab Chip, 2009, 9, 503
DOI: 10.1039/b815716b

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