Scientists have developed a green way to make chemicals based on sun and surfing - well, they are Hawaiian!

The floating reactor makes organic compounds using solar energy

Robert Liu, from the University of Hawaii, Honolulu, and colleagues have designed a solar reactor that floats on the ocean and synthesises organic compounds under the Sun. The reactor uses solar energy to make hindered isomers of vitamin A. While these isomers aren't particularly useful, Liu believes he can use the method to make other products.

Photochemical reactions use a molecule's ability to capture a photon from the Sun. This energy is then used for chemical reactions that cannot usually be done by heating. Liu used a method called triplet sensitisation, where light is absorbed by a coloured material and the excess energy is passed on to the reactant. 'In this way, we can tap a major portion of the visible light from the Sun,' says Liu.

The reactor does not require electricity or running water and is small enough to be fitted into a boogie-board (a small surf-board). The reactor uses the Pacific Ocean as an immense heat sink to dissipate any excess heat. The reactions can be done within half an hour, the time period of a short surfing session, says Liu.

'An appealing idea,' says Axel Griesbeck, an expert in photochemistry at the University of Cologne, Germany. 'We need to support experiments like these now and not wait for the end of all natural oil, gas and coal.'

Sarah Corcoran